NAT'L INST. OF STAND & TECH

AlllOb flbE7flS

NBSIR 75-935

WIST

PUBUCAUONS

The National Measurement System

for Electricity

Norman B. Belecki

Bernadine L. Dunfee

Oskars Petersons

Electricity Division

Institute for Basic Standards

National Bureau of Standards

Washington, D.C. 20234

Issued September 1978

7 ^ ^TMENT OF COMMERCE

. tC6 ^ JREAU OF STANDARDS

NBSIR 75-935

THE NATIONAL MEASUREMENT SYSTEM

FOR ELECTRICITY

Norman B. Belecki

Bernadine L. Dunfee

Oskars Petersons

Electricity Division

Institute for Basic Standards

National Bureau of Standards

Washington, D C. 20234

Issued September 1978

U.S. DEPARTMENT OF COMMERCE, Juanlta M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
1
PREFACE

The National Measurement Systeni for Electricity is that systerr of people, organizations,

standards, apparatus, and software which performs the function of providing quantitative inforination on materials, manufactured items, and processes through the measurement of their

physical properties or parameters. This report is one of a series of similar reports produced by the Institute for Basic Standards (IBS) of the National Bureau of Standards to provide a complete description of that system, of which IBS is the foundation. The format of

this report is common to the series and was chosen to provide uniformity and completeness.

The authors would like to express their appreciation to their many colleagues who supplied information and perceptions for inclusion in this study. Special appreciation goes to those who arranged or hosted visits at private and government organizations for the authors

and others of the Division staff. We would like to also acknowledge the v/ork of Denise

Prather, who assisted in the production of the final draft. Finally we are most indebted

for the efforts of Sylvia Ramboz, who was responsible for the production of the manuscripts

for two interim reports as well as this document; and for her comments, suggestions, and

encouragement.
CONTENTS

Page

PREFACE i

EXECUTIVE SUMMARY 1

1. INTRODUCTION 3

2. STRUCTURE OF THE ELECTRICAL MEASUREMENT SYSTEM 4 2.1 Conceptual System 4 2.2 Basic Technical Infrastructure 7 2.2.1 Documentary Specification System 7 2.2.1.1 Standardization Institutions 7 2.2.1.2 Survey of Documentary Standards 9 2.2.2 Instrumentation System 10

2.2.2.1 Measurement Tools & Techniques 10

2.2.2.2 The Instrumentation Industry 14 2.2.3 Reference Data 16 2.2.4 Reference Material 16 2.2.5 Science and People 17 2.3 Realized Measurement Capabilities 18

2.4 Dissemination and Enforcement Network 22 2.4.1 Central Standards Authorities 22 2.4.2 State and Local Offices of Weights

and Measures 22 2.4.3 Standards & Testing Laboratories & Services 22 2.4.4 Regulatory Agencies 25 2.5 Direct Measurements Transactions Matrix ..... 26 2.5.1 Analysis of Suppliers and Users 26 2.5.2 Highlights re Major Users 26

3. IMPACT, STATUS AND TRENDS OF the MEASUREMENT SYSTEM 35 3.1.1 Functional, Technological, and Scientific

Applications 35

3.1.2 Economic Impact - Costs and Benefits 36 3.1.3 Societal and Human Impacts 37 3.2 Status and Trends of the System 37

4. SURVEY OF NBS SERVICES 43

4.1 The Past 43

4.2 The Present Scope of NBS Services 43

4.2.1 Description of NBS Services 43

4.2.2 Users of NBS Services 50 4.2.3 Alternate Sources 50 4.2.4 Funding Sources for NBS Services 51 4.2.5 Mechanisms for Supplying Services 51 4.3 Impact of NBS Services 51 4.3.1 Economic Impact of Major User Classes 51 4.3.2 Technological Impact of Services 52 4.3.3 Pay-off from Changes in NBS Services 52 4.4 Evaluation of NBS Programs 54 4.5 The Future 55

5. SUMMARY AND CONCLUSIONS 57

i i
Page

APPENDIX A - The Measurement System Study 59

APPENDIX B - NBS Primary and Working Electrical Standards 63

APPENDIX C - "Critical Electrical Measurement Needs and Standards

for Modern Electronic Instrumentation" - Workshop

Report Abstract, Forward, and List of Attendees 67

APPENDIX D - Standards and Calibration Laboratories 71

APPENDIX E - Typical Measurement Support Structures 75

REFERENCES ^ 79

BIBLIOGRAPHY

LIST OF FIGURES

Figure 1. The derivation of the electrical units 6 Figure 2. Traceability of voltage measurements 12 Figure 3. Traceability of energy measurements 13 Figure 4a. Uncertainties of measurements 19 Figure 4b. Uncertainties of measurements 20

Figure 5. Typical corporate support structure 24 Figure 6. Organizational transactions matrix 27 Figure 7. Code for transactions matrix 28

LIST OF TABLES

Table K Electrical quantities and units . . » . , o „ » o » » » o , . o o . o o » 4 Table 2 Characteristics of the basic legal units o oo o o 7 Table 3. lEC cormii ttees affecting the

Electrical Measurement System „ . . „ o » o . . „ o „ o » o » . » „ ^ « 8 Table 4o OIML Pilot Secretariat 13 . o » oo oo o o o. o » o „ 8 Table 5^ Voluntary standards sponsoring organizations ^ „ o o o » o „ o « o o o o . 9 Table 6, Basic units and industrial standards , o oo o o „o. o.„.„ 11 Table 7o List of common instruments . . o . . „ . . o . o . . . „ » o o » . „ . . „ 1

5

Table 8. List of electrical standards manufacturers o ..... o .. o o o . 15 Table 9. Sample sources of reference data for engineers o.. o » o 17 Table 10. Regulatory agencies and agency categories „ . . . . . . „ . . o . . . . . 25 Table lU Representative heavily measurement-dependent

products o ^ 36 Table 12. Electricity Division technical outputs . . . . . . „ „ . . . » . . . . „ o 47

Table 13. Dissemination services of the

Electricity Division ^ ^ ^ ^ „„„ 48

Table 14. Users of NBS Services ...... ..o .... „„o ... o. o.o„„ 50

Table 15. Electricity Division user classes . ................... 51

i i 1

THE NATIONAL MEASUREMENT SYSTEM FOR ELECTRICITY

Norman B. Belecki

Bernadine L. Dunfee

Oskars Petersons

Electricity Division

Institute for Basic Standards

June 1976

EXECUTIVE SUMMARY

Electrical measurements are of critical

imoortance due to the universal use of electricity as the primary means for the trans- mission and control of energy and data. The

National Measurement System for Electricity

is that set of laboratories, organizations,

documents and people which make possible

and are responsible for all electrical mea- surements made in the U.S. at all levels of

accuracy. This document summarizes the results of a four-year study of that system.

The structure of the system may be con- ceived as having a number of components,

each serving a particular sector of society

and each having distinct characteristics re- flecting differing requirements. Two major

components exist: the industrial electronics

component and the electric power industry

component. There are a number of minor

parts in each.

Electrical measurements in the system's

industrial electronics component are used to ensure quality and reliability of materials

and manufactured products, to provide for

interchangeabil ity of components and parts,

and to control meanufacturing processes.

This component can also be further subdivided into two general areas: the measure- ment-intensive industry segment and the general industry segment. Measurement-intensive industry and its measurement system are characterized by high technology and the need

for a very high degree of product reliability.

Included in this portion of the defense, com- munication, computer, and electronic component

industries. Measurement accuracy withi n this

segment is ensured by a hierarchical laboratory system in each organization. Test equipment used for quality and process control is calibrated periodically using precision instruments which are in turn calibrated by

comparison with primary standards in the cor- porate standards are then periodically calibrated at the National Bureau of Standards or

i ntercompared regularly with standards which

have been so calibrated. This system, which

in large organizations can have a complex

hierarchy of laboratories, is primarily the

result of the quality control requirements

of DoD, OSA, and NASA procurement contracts,

the reouirements of regulatory agencies such

as EPA and OSHA and logistics constraints.

In the general industry segment of the

system. Quality control requirements are usually less stringent than in the high

technology segment; accuracies are generally

lower; and the manufacturing processes are

less affected by absolute accuracy of measurements. Thus, organizations in this

portion of the system are inclined to buy

calibration and repair services from instrumentation manufacturers, large corporate

laboratories in the aerospace industry, or companies specializing in calibration and

repair work. As previously noted, each of

these generally maintains a rigid, well-defined measurement support system.

There appears to be a number of problems

and shortcomings in the industrial electronics component of the system. Among the most

important are a lack of standards (written

and artifact) for the support of dynamic,

high-speed electrical measuring instruments

and automated test systems; the non-availability in certain areas of procedures and

test techniques of guaranteed reliability;

a potential future shortage of competent

measurement personnel; a failure on the part

of some people in the system to perceive

that calibration is not always a sufficient

condition for assurance of measurement Quality; and an inherent rigidity in the government contractural requirements which stifles

innovative approaches to measurement prob1 ems.The electric power industry segment of

the National Measurement System for Electricity can also be divided into two parts:

operational and research for improved electric power transmission and distribution.

Electrical measurements play an important

role in the day-to-day operation of the na- tion's electric power systems. They are

used to control the generation and trans- mission of electricity, to provide a basis

for equitable exchange (energy metering),

and for testing machinery and equipment sup- plied to the power companies.
Measurement support for both of these areas is generally provided by the measurement laboratories of power companies and

those of the electrical eauipment manufacturers. In the energy metering area, many

of the state and local public utility com- missions which regulate the power companies

require acceptance testing of watthour meters as well as retesting of older meters.

NBS calibration of physical standards and

electrical apparatus, both at NBS and in the

power companies' and manufacturers' laboratories, ensures the overall integrity of the

system.

Most of the industry - both utilities and

manufacturers - is adequately equipped to measure traditional quantities such as current and voltage at levels up to 15 kilovolts. Fewer companies, especially in the

utility sector, have capabilities above 100

kilovolts. At extra-high voltage (EHV) and

ultra-high voltage (UHV), the utility companies, with rare exceptions, have little

measurement and calibration capability.

Such capability, however, does exist with

the manufacturers of large electrical equipment. With respect to nontradi tional quantities, such as transient high voltages and

currents, measurement capability is generally

available only with the large equipment manufacturers.

The quality and consistency of electric

power system-related measurements, including

traceability to NBS-maintained standards,

follow the above pattern of measurement ca- pability. Whenever the calibrations are relatively simple and inexpensive, and if

there is also regulatory incentive to do

adequate work, the system is in excellent

condition. A good example is watthour meter

calibrations. But for higher voltage, and

especially for non-conventional measurements

where the calibrations are difficult to perform and reliable methods are not always

readily available, the system has deficiences. Included in this category and EHV and UHV steady-state measurements, and transient measurements in general.

Electricity will become the predominant

form of energy in use before the end of the

century. Consequently, a large research and

development effort funded by the Energy Re- search and Development Administration and

the Electric Power Research Institute is being directed at ways to increase the transmission capability and efficiency of the

country's electric power systems. New high

voltage and electrical-related measurements

are required as transmission technology ad- vances. Examples of new technologies include cryogenic transmission systems, UHV overhead lines, compressed-gas insulated

substations, and high-voltage directcurrent transmission systems. Each is a relatively measurement-intensive, emergingtechnology area. While some older types of

measurement methodologies can be adapted

for these new areas, generally they cannot

and some significant deficiencies now exist including measurements for accelerated

aging tests of electrical insulation, and

traceability to national standards for impulse measurements.

Two important additional components of

the National '"'easurement System for Electricity are associated with the scientific

community and consumer electronics. Measure

ments made in laboratories not under DoP or

NASA contract are generally supported by

local instrumentation shops. In contrast

with the usual practice in the industrial

electronics component, periodic recalibration is unusual - calibration is generally

performed only before and after a crucial

experiment, or as part of a special maintenance effort. Measurements in support of consumer electronics, such as TV, stereo sys tems, citizen band and amateur radio, auto

electronics, and general electrical work are usually of low accuracy. Consequently, manu

facturers' claims of test equipment accuracy

are accepted until malfunction occurs. This

portion of the system has few, if any, serious measurement problems.

In summary, the Electricity Division of

NBS provides the basis for that uniform sys- tem of electrical measurement in the U.S. . which permits equity in trade, interchangeability of components, the transmission and

distribution of electric power, a means of

maintenance for electronic equipment, the

ability to control the quality of production, and the general advance of science

and technology. This is achieved by developing improved means for realizing, maintain

ing, and disseminating the basic electrical

units; by calibrating electrical standards,

instruments, and systems for industry, government, and the academic community, by

developing new instrumentation and measurement methods; by obtaining basic data and

determining fundamental constants related

to the electrical units; by ensuring that

electrical measurements carried out in the

U.S. are consistent with those made in other

countries; and by providing advisory and con sultative services.

2
1 . INTRODUCTION

The National Electrical Measurement System began to assume its present form around

the beginning of this century. At that tirne the uses of electricity were limited to the

easy transmission and use of energy in manufacturing and transportation and for lighting and primitive means of communication

(telephone and telegraph). The establishment in 1901 of the National Bureau of Standards led to the foundation of a uniform

system of electrical measurement v/here none

had existed before; a foundation v;hich permitted and expedited the development of

electrotechnology v;hich has made our present

way of life possible. Since then the mea- surement system has continuously grown in magnitude and scope along with the industries

it supports [1].

Today the system pervades every aspect of

modern life. The electric power industry is the largest in the United States [2]. The

electronics industry is one of the larger

industries as well, and its products make

possible the inexpensive production of goods

and services throughout the rest of industry. Our present level of electrotechnology

is only possible because a uniform system of

electrical measurement exists. This system

provides scientists, electrical engineers,

and quality control engineers with a common language and thereby minimizes the need for

trial -and-error approaches to design by permitting the existance of necessary data

bases and allowing the meaningful communication of technical information in quantified

detail. It is also true that the level of

sophistication and general quality of all electrical -electronic products as well as many others are predicated, among other factors, on the state of the measurement system. The stability with time of the units

of measure, the compatibility of measurements throughout the system, and the effectiveness with which new requirements are anticipated and dealt with are key factors

which establish bounds on the level and rate of advance of technology. The system permits interchangeabil ity, at affordable cost,

of parts with very high levels of precision,

a vital part of modern manufacturing technology.

The study of the National Electrical Measurement System, the results of which are summarized in this report, is intended to provide a complete picture of the system at the present time, and to forecast its future

posture, needs, and shortcomings. The present intensive study -is also to provide a data base for program planning within the

National Bureau of Standards, a data base

which will be expanded over the years as the

result of a continuous surveillance of the

system. The study v/as carried out primarily

in two parts. Technical data were gathered

as the result of visits to companies, corres- pondence with colleagues, interviews with

visitors to the NBS, and interactions' with

fellow members of standards committees by

Electricity Division personnel. Economic

data were gleaned primarily from the literature. Because of the nature of the Electrical Measurement System, separate studies

were not conducted on each measurement area. Rather, the system was observed as consisting of tv/o uniaue sets of users, the electric power industry and the electronics industry. The term "electronics industry" as used here refers not only to the manufacturers of electronic components, modules,

instruments, and systems, but to the users

of these as well. Each of these will be

further subdivided as the report progresses.

Since the system is so large and pervasive,

no attempt was made to define its size exactly. Recurring structural features make

sampling an effective means of viewing the

system.

As a result of the study, it was determined that:

(a) the system is adequately equipped and

manned to support most measurements of a static nature;

(b) although most new instruments are designed and specified for use under computer

control, there is virtually no capability in

the system as a whole to support dynamic measurements; i.e., measurements in which time

is a factor;

(c) there are expected to be increasing

pressures from government regulatory agencies and from industrial firms engaged in

international commerce for the establishment

of a system for accrediting standards, calibration, and testing laboratories of various

types

(d) future sophisticated instrumentation,

if not designed for computer control, will

contain small control and logic units called

microprocessore, creating a need for methods

of verification of measurement implementation softv/are;

(e) there exists a need, whose urgency is

being determined, for improved measurements

of electrical conductivity for application

to non-destructive materials testing;

(f) because of the energy crisis, there

is a need for new measurement methodologies

for the support of energy-related research,

especially in the areas of electric power;

(g) there is a lack of capability within

the electric power industry to perform ultrahigh voltage measurements;

(h) the exchange of technical information

takes place in the system at an unacceptably

1 ow 1 evel

.

3
It must be noted that consideration in

this study was not given to those electrical

measurements associated with the processing

of semiconductor materials. Such measurements are addressed in depth by the impact

study of the Electronic Technology Division

of NBS.

2. STRUCTURE OF THE ELECTRICAL

MEASUREMENT SYSTEM

2.1 Conceptual System

The system provides the capability for measurement of electrical quantities shown in table 1 below in the frequency range between

dc and 1 MHz.

Table 1. Electrical quantities and units

Quantj_ty_ Uni ts

Capacitance (C) Farad

Current (I) Ampere

Charge (Q) Coul omb

Potential Difference (E) Volt

Inductance (L) Henry

AC-DC difference. vol tage (Uni tl ess)

AC-DC difference, current (Uni tl ess

)

AC-DC difference, resi stance (Unitless

)

Power Watt

Energy Watthour

or Joule

Ratio, resistive (Unitless)

Ratio, dc voltage (Unitless)

Ratio, ac voltage (Unitless

)

Ratio, current (Unitless)

The above are measured in terms of the so- called legal units, those embodied in physical standards maintained by the National

Bureau of Standards or defined by them as a function of physical constants. These units are - to the degree practical - compatible

with the SI (Syst&me International) units.

The Syst&me International de'Unites provides the internationally accepted theoretical basis for the metric units of measure.

In it, seven base units - the metre, the

kilogram, the second, the kelvin, the mole,

the candela, and the ampere - are regarded

as being dimensional ly independent and all other units stem from them, either through

known physical relationships or defining

equations [1]. In practice a set of four

independent equations is available to define

the six basic electrical quantities given at the top of table 1 with their symbols. They

are E=IR (Ohm's Law); Q=It (t is time);

C=Q/E; and L=E/-^. These can serve to define only four of these Quantities. The

system is completed by requiring the unit of

electrical energy to be equal to the unit of

mechanical energy and devising electromechanical experiments - absolute experiments - involving force and length (whose product is energy) and corresponding electrical quantities to realize in practice two of the

electrical units.

Absolute experiments are very complex and

time-consuming, require the most meticulous

approach, and involve the design and con- struction of special apparatus. Moreover,

in the case of the ampere and volt, the un- certainties of the results are very large by

comparison with those attainable using

either artifacts, such as standard resistors

or capacitors, or physical phenomena (e.g.,

the Josephson effect) to carry forth defined

units. It is for these reasons our system

of legal units exists. Figure 1 shows in detail the derivation of assigned values for

the legal electrical units. In the past,

absolute experiments have been performed to realize the ampere by comparing the force

between current-carrying coils of known geometry to that exerted by the earth's gravitational field on a known mass. This was done most recently at NBS in 19F7 using a Pellat-type electrodynomometer. The result

was the determination that the ratio of the

NBS ampere (derived from the legal units) to the SI ampere equals 1.^000105 with a probable error of 7 parts in a million.

These results as well as those of four

other experiments formed the basis for an eleven part per million adjustment in 1969

to the value of the ampere as derived from

the units maintained in Sevres by the Bureau

International des Poids et Mesures - the In- ternational Bureau of Weights and Measures,

which by the treaty of the Metre maintains

electrical and physical units to promote international measurement uniformity. In con- sequence of this adjustment and drifts in

the U.S. volt measured with respect to the BIPM volt, the U.S. legal volt was changed

by 8.^ parts in a million on January 1, 1969.

U.S. laboratories were informed of this

change and advised to make the appropriate

adjustments to the assigned values of their

standard cell emfs through correspondence

and technical publications in the media.

The ohm has in the past been determined

in absolute measure using a specially con- structed coil system of known geometry. The

mutual inductance of such a system may be

determined from its geometry and dimensions

using electromagnetic theory. A commutated

dc method may then be used to obtain the

4
value of a resistance as a linear function

of the mutual inductance (length) and the rate of commutation (time). The resulting

overall uncertainty of the last experiment

of this type performed at NBS in 19^8-19^9

was 10 parts per million [2] - rather large

especially when compared to the precision

with which resistance standards may be intercompared ("0.01 ppm) and their drift rates relative to one another ('^0.05 ppm/year).

More recently, it has been determined using

a calculable cross capacitor. This device

is based upon the theorem of Thompson and

Lampard which describes geometric conditions

for the construction of a device whose ca- pacitance is a known function of the displacement of a moveable electrode and hence

can be calculated if the displacement can be

measured. A quadrature bridge is then used

to effect a calibration of resistance in terms of capacitance. This experiment thus

establishes both the farad and the ohm in absolute measure. This is a much more ac- curate experiment than either the previouslydescribed ohm determination or the ampere determination, having an uncertainty of 0.06

ppm [3].

The volt may also be obtained in absolute

measure. Experiments are now underway at NBS and in the national laboratories of

several other countries. The MBS experiment

involves the measurement of the dc voltage

applied to concentric cylindrical capacitors

in terms of the electrostatic force generated between them as a function of their

relative displacement and the charge In ca- pacitance resulting from the displacement.

The target accuracies of these experiments

is of the order of 1-3 ppm. When completed,

these determinations will not only provide

the difference between the maintained and SI units of voltages, but when coupled with the

results of the Farad-Ohm determination, will

constitute an indirect determination of the

SI ampere for comparison with previous directly-obtained values.

The legal units are maintained at MBS in

the form of assigned values to groups of

artifact standards. The legal farad is

embodied in a group of'ten, very stable,

fused-silica capacitors [4]. The mean ca- pacitance of the group has been assigned

from absolute capacitance determinations.

The legal ohm is the mean 4-terminal re- sistance of a group of Thomas-type standard

resistors immersed in oil at 25°C under a power dissipation of 0.01 watts. This value

is slightly inconsistent with the results of

absolute experiments and will be adjusted

after further work. It is not anticipated

that this adjustment will he as large as one part per mil 1 ion.

The ampere, however, cannot be conveniently maintained using a physical standard.

Instead, the absolute measurements of resistance and current are used to derive an absolute volt from which a legal unit of voltage may be assigned. Until 1972, the volt was maintained via a group of saturated

standard cells in a temperature-controlled

enclosure. Since July 1, 1972, use has been

made of the ac Josephson effect to maintain

the legal unit. The ac Josephson effect is

a superconducting, pair-tunneling phenomenon

- the discovery of which has permitted the

construction of a linear f reouency-to-vol t- age converter whose proportionality constant

is invariant with respect to time and other

factors at the part in 10^ level [5]. Figure 1 depicts the derivation of the basic

electrical units. It does not show an ex- periment for the direct absolute determination of the volt presently underway. Table

2 gives characteristics of the artifacts

embodying the legal units. Appendix B con- tains a description of both the primary

electrical standards and the working stan- dards used to provide for the dissemination

of the electrical units.

The other quantities listed in Table 1 are derivable at various levels of accuracy

over their ranges. Accuracies of calibrations of standards in each of these areas are more than adequate to meet most static

measurement requirements except the following :(a) Capacitance between 30 kHz and 1 MHz,

needed to support measurements resulting

from increasing carrier frequencies in com- munications systems.

(b) AC voltage from 0.1 Hz to 100 Hz at millivolt levels and below for the support

of vibration measurements aboard helicopters.

(c) DC conductivity measurements in fer- rous and nonferrous metals for the support

of nondestructive testing of airframes and

other structures.

The standards and capabilities mentioned

to this point apply only to static measurements, i.e., those measurements for which

the time of measurement is not a constraint.

The advent of integrated circuits and the

resulting enormous increase in complexity of

electronics has resulted in requirements for

many more measurements in industry to ensure

the quality of products and for maintenance

purposes. Manual measurement methods are totally inadequate to the demand. Fortunately this same new technology has provided

the system with the tools needed to perform

measurements at very high speeds - fast settling instrumentation to convert analog electrical parameters to encoded digital signals,

high-speed data handling equipment for routino digital and analog signals, and readily

available inexpensive digital computers to control experiments, collect data, direct it
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Table 2. Characteristics of the basic legal units.

iNonii na 1 rial ritcilaiH-c A Ken 1 1 1^ o Unit Artifact Value Accuracy Accuracy

Ohm Thomas-type resistor 1 ohm 0.08 ppm .06 ppm

Volt Josephson apparatus 10 mV 0.1 ppm 7.8 ppm

Farad Fused-sil ica capacitor 10 pF 0.4 ppm 0.034 ppm

Henry Maxwell -Wein bridge 200 ppm 200 ppm

^Maintenance accuracy is that with which a perfect standard of equal

magnitude could be calibrated.

Absolute accuracy is the accuracy with which the difference between

the SI and legal units has been reported.

to storage devices, and perform the mathematical manipulations necessary to put it in useful form.

Unfortunately, standards to provide a basis of accuracy for these high-speed or dynamic measurements simply do not exist.

There is no common, well-defined terminology

for describing the performance of these modern measurement tools, nor are there ac- cepted test methods or artifact standards

for verifying their accuracy under use conditions. There is no reliable way of precisely determining the trade-off between

speed of measurement and accuracy. Presently, dynamic measurements are supported

through the rapid measurement of static standards, a practice which does nothing to verify the capability to measure the rapidlyvarying parameters characteristic of modern

electronics. Other time-related properties

of the measurement instrumentation such as the rate at which they should sample, the

frequency of the measurements made, or delay

times after switching are determined on a trial -and-error basis. Such standards as do

exist are the intracomnriny standarr's o-^ each

of the instrumentation and module companies

and, while they serve to achieve a degree of

uniformity within each company's product

line, are not directly relatible on an intercompany basis and certainly not available to the customers of the companies. In fact,

such standards are considered proprietary in that they seriously af-'^ect product development in one of the most competitive marketplaces in existance.

This lack of standards and measurement

verification capability results in undue

costliness of measurement equipment, in hard- ware, testing and design costs, and in un- fulfilled measurement capabilities. Undue

cost accrues as the result of overspecif ication of components and modules at design

time. In addition, validation procedures

must be developed by trial -and-error techniques where adquuate standards do not exist.

A program for the development of standards

and test techniques to support the dynamic

measurement of electrical parameters has re- cently been initiated within the NBS. It is visualized that the hardware and written

standards developed in this program will be

made available to manufacturers and users of

electronic measurement equipment in the form

of calibration services, measurement assurance programs, and publications. As such

they will provide the basis needed for uniform and compatible dynamic measurements

throughout the country in the same way that

existing standards now do for manually-made

measurements

.

2.2 Basic Technical Infrastructure

2.2.1 Documentary Specification System

2,2.1.1 Standardization Institutions

There are 'basically two major international standardizing organizations impacting

the Electrical Measurement System. The In- ternational Electrotechnical Commission (lEC)

is concerned with the production of standards, terminology, and specifications in support of el ectrotechnol ogy . It has ap- proximately 75 technical committees to perform this function. A list of those technical committees most affecting the system is given in table 3. In this country, a delegate to each committee of interest is ap- pointed by the chairman of the national com- mittee. The delegate, in the case of each

proposed standard, attempts to develop a consensus U.S. position by getting technical

support from interested parties in industry

and government. The work of the lEC is very

important to U.S. foreign trade activities.

If standards which are essentially incompat7
ible with common American practice are developed, they could be used against the U.S.

in restraint of trade. More importantly,

standards developed overseas tend to be re- strictive in two other ways. In many cases, methodology is stressed rather than performance. This tends to inhibit technological

advancement in some product areas. Furthermore, the level of technology reflected in some standards is low by comparison to that

in the U.S. These two factors can readily

couple to close foreign markets to U.S. manufacturers.

Tanle ,1. lET committees affecting the

Electrical Mea surement System

Copimi ttee Title -

,

.

1 , Terminol ogy

Graphical Symbols

13 Measuring Instruments

25 Quantities and Units, and

their Letter Symbols

38 Instrument Transformers

42 High Voltage Testing Techniques

45 fJuclear Instrumentation

sn Environmental Testing

56 Reliability and Maintainability

62 Electrical Equipment in Medical

Practice

66 Electronic Measuring Equipment

The International Organization for Legal

Metrology (OIML) is a recently-formed group

concerned with legal aspects of metrology,

such a-s weights and measures, k'ithin OIML

is a pilot secretariat. Secretariat 13, for

the measurement of electric and magnetic

quantities which is concerned with the provision of traceability for those kinds of

measurements presently legally required.

Secretariat 13 is held by the U.S. and has

the subcommittees listed in table 4. Within the U.S., there are a wide variety

of legal and regulatory standards which impact the Electrical Measurement System. In the electronics world, traceability reauirements for suppliers are made mandatory

through contract by the federal government's

largest consumers: the Department of Defense,

the Department of Transportation, and the

National Aeronautics and Space Administration. The Department of Energy requires

that all contractors running installations

for them have a stylized quality control system, and they provide for the servicing of

those systems through their laboratory in Albuquerque, NM, run by the Sandia Corporation.

Table 4. OIML Pilot Sec retariat 1 3

Mieasureinent of Electric and

flagnetic Quantities

Subcommi ttee Title

13.1 International Compatibility

of Primary Etalons

13.2 Power Meters (wattmeters)

13.3 Energy Meters for Direct

Connecti on 13.4 Energy Meters Designed to

be Used With Measurement

Transformers

13.5 Mieasurement Transformers

13.6 Indicating Instruments for

Voltage, Current and

Frequency

13.7 Recording Instruments for

Voltage, Current and

Frequency

The Department of Defense contractually

requires of its suppliers compliance with

military specifications MIL-Q-9859A, Quality

Program Requirements; f1IL-I-45208A, Inspection System Requirements; and Vll-t-^bFfZ^,

Calibration System Requirements. By doing

so, it forces manufacturers to set up calibration and quality control systems which

require periodic calibration of all measurement equipment, traceability to national

standards in the case of all such calibrations, complete documentation of the calibration system including test procedures and

traceability, and any instrument undergoing

calibration to be tested using standards at least four times more accurate than it is. NASA has a similar but more rigid set of

regulations - MPC 200-lA, Quality Assurance

Provisions for Space Contractors. The De- partment of Transportation requires traceability in its highway safety test programs

by specifying compliance with provisions of

the Society of Automotive Engineers' Standard J211b.

Of great potential impact are new and

forthcoming requirements of the Occupational

Safety and Health Administration (OSHA).

That organization has proposed that all industrial electronic and electrical equipment

comply with certain minimum safety standards.

Furthermore, it is proposed that all devices

be tested for compliance in certified testing laboratories and that tests must be con- ducted in a laboratory not belonging to the

manufacturer of the item being tested. At present these proposals are being appealed

by industrial groups.

8
The electric power industry subset of the

measurement system is also affected by the

mandatory safety requirerrents of the Occupational Safety and Health Administration.

Safety testing will be required of apparatus

used in work environments. Once again it is

likely that all testing will be done by ac- credited laboratories.

At present, the Food and Drug Administration fosters safety standardization in the

manufacture of medical devices and instrumentation by sponsoring and promoting the

generation and adoption of standards with

the voluntary cooperation of industrial concerns, medical experts, and their own experts. Recently (May 1976) enacted and

signed into law is The Medical Device Safety

Amendment to the Food, Drug and Cosmetic

Act, which will set up control mechanisms

for medical instrumentation administered by

the Food and Drug Administration. These

mechanisms will range from having to obtain

approval before marketing to simply having

to register products in such a v/ay as to enable an effective recall process in the

event defects are found. In addition, manufacturers will be subject to a number of

standards called f?ood f-'anufacturina Practices. These Pood ''anufacturing Practices,

about to be promulgated, will require the

existence of formal Quality control procedures (in many cases where none exist now)

and, in some areas of critical application,

the establishment of formal calibration

support systems with measurements required

tn be accurate in tern's of national standards. This will result in the creation of

nev/ standards laboratories and perhaps in

recognition of new types of measurement

appl fcations.

The bulk of the regulations affecting the

electric power industry come from state

utility regulatory comriissions. These com- missions have broad powers in regulating the

operations of electric utility companies.

They approve rates and siting of power plants

and major transmission lines; to some extent

they have a jurisdiction over the ouality of

electric power service—occasionally they

prescribe tolerances for the supply voltage';

they regulate the accuracy of watthour meters and the quality control systems which

have been set up to test both newly-acouired

and previously-installed meters.

There are a large number of voluntary

standards organizations impacting the Electrical ''easurerent System. The majority are

listed in table S. Those organizations

whose titles are starred have the greatest

impact since they produce standards which

have affect on the higher accuracy measurement processes, instruments, and artifact

standards which support the system. f'ES

personnel participate in the activities of a number of committees sponsored by each of

these organizations.

Table z. Voluntary standards sponsoring

orcanizations

Aerospace Industries Association

American Home Lighting Institute

*American National Standards Institute

American Society for Quality Control

American Society for Testing and Materials

American Welding Society

Association of American Battery

'anufacturers

Association of Edison Illuminating

Companies

Audio Engineering Society

*Edison Electric Institute

Electric Apparatus Service Association

*Electronic Industries Association

*Institute of Electrical and Electronic

Engineers

Institute of High Fidelity

Institute of Printed Circuits

*Instrument Society of America

National Association of Relay f^anufacturers

*National Electrical [Manufacturers

Association

Radio Technical Commission for Aeronautics

Resistance I'elder Manufacturers Association

*Scientific Apparatus Manufacturers

Association

Society of Automotive Engineers

Undenvriters Laboratories

Variable Resistive Components Institute —nOrganizations having major inpect

2.2.1.2 Survey of Documentary Standards

A survey on documentary standards affecting the electrical measurement system was performed. Consideration of documentary

standards in the electrical area shows that

the documents may he divided into six categories: safety specifications and testing

methods, terminology, dimensional requirements for compatibility, testing methods to determine electrical properties, performance

parameter specifications and testing, and

reliability assurance procedures. It is ap- parent that all except dimensional requirements involve or affect electrical measurements in some fashion. Since there v;as no evident valid means of ranking or nuantifying these various effects, and since any

document directly concerning etalons (artifact standards), measurement apparatus, and

instrumentation would be more likely to have

a large impact on the measurement system,

those documents were consider-^d separately.

9
Investigation of documents sanctioned by

the International El ectrotechni cal Commission

showed that, of the population of 759 standards and supplements, 45 referred directly

to etalons, instrumentation, and precision

measuring equipment. Most of these specify

moderate accuracy instrumentation. Of the

remainder, perhaps ten percent deal v/ith

terminology and symbols and another ten percent with dimensional specifications. As has been pointed out, the remainder have a bearing on the segment of the system dealing

with the testing of export products for com- pliance with these standards to assure ac- ceptance abroad. And, although a third or more of the remaining documents refer to radio frequency measurements above 1 MHz and

therefore outside the scope of this study,

measurements at those frequencies require a degree of low frequency measurement support

[6].

A similar investigation of standards issued by the American National Standards In- stitute and having bearing on electricity and

electronics, revealed that, of standards,

supplements, and handbooks issued, 2n provided definitions, specifications of performance, and test and verification methodology

for standards, instrumentation, and precision measurement apparatus. Terminology is

largely concentrated in 042.100, the Institute of Electrical and Electronic Engineers

(IEEE) Standard Dictionary of Electrical

Terms. About ten percent of the documents

in this study specify dimensions for compatibility. The remainder specify or outline

tests or measurements of various electrical

parameters. The standards sanctioned by

this institute are perhaps the most universally accepted in this country. A very high

percentage of them have been adopted directly from the work of other groups such as the

IEEE, the National Electrical Manufacturers

Association, and the American Society for

Testing and Materials [6]. mary standards

General ly speaking, IEEE standards dealing directly with measurement apparatus,

instrumentation, and etalons have been

adopted by the American National Standards

Institute and, hence, are covered above.

Standards and recommended practices produced

by the Instrument Society of America deal

primarily with the application of instrumentation to industrial processes and with the use and measurement of transducers. There

are 18 such procedures involving electronic

instrumentation. Standards produced by the

Electronic Industries Association deal primarily with electrical testing of components

and with electronics in the manufacturing

process

.

The Edison Electric Institute, the As- sociation of Edison Illuminating Companies,

and the National Electrical Manufacturers

Association have contributed to standards

for electric power systems, either through

sponsorship of, or participation in, ANSI

committees. In the measurements field three

standards are very prominent: ANSI C12

(watthour meters, electricity metering; com- mittee is chaired and co-sponsored by NBS);

ANSI C57.13 (instrument transformers); ANSI

C93.2 (coupling capacitor voltage transformers) [7]. The IEEE is a very important

contributor to the measurement and test stan- dards for electric power systems through the

Power System Instrumentation and Measurements (PSIM) Committee and its subcommittees

and working groups. This committee is re- sponsible for about 10 standards, most of

which have been adopted by ANSI.

There are two areas in which the standards reviewed have little or no impact.

The first is the area of the dynamic mea- surement of electrical processes in which

timing is a significant factor. With the

increasing use in this country of computerdriven measurement equipment, standardization of terminology and specification of

valid timing test methods are necessary to relieve the chaos which presently exists in

the marketplace for that type of equipment

[6]. (See also Appendix C.)

Methodology for testing the measurement

system is not well documented as such. Although documentation of tests on certain

types of instruments is available, techniques for the verification of the measurements are not documented. No mention is

made in published standards of the type of

system-output sampling that is employed in many of the Measurement Assurance Programs

being carried out by the NBS. The importance of these voluntary standards is reflected by the support given to their generation by industry and the government. Most standards committees meet at least biannually and the meetings are generally well attended even though the participants are from various parts of the country.

And, although the use of these standards in this country is on a voluntary basis, their

generation oives a solid technical base for

U.S. input for international standards work,

the results of which may carry the force of

law in other countries. Heavy and successful U.S. activity in that area is needed to enhance our export trade posture.

2.2.2 Instrumentation System

2.2.2.1 Measurement Tools and Techniques

Practical (end use) measurements in the

Electrical Measurement System are supported

by a hie>"archical structure resembling an Inverted pyramid with the National Bureau of

10
standards as its base. At NBS, the legal

electrical units, which have been determined

in terms of the theoretical (SI) units, are maintained and disseminated to the standards

and calibration laboratories of the community. (See Appendix E for a list of NBS primary and working electrical standards.) The

units are transferred there from standards

to a class of instrumentation commonly known

as test equipment. It is this test equipment which provides the means for the calibration and maintenance of virtually all electronic and electrical equipment in the

country, regardless of its nature.

A few basic types of standards, used in

corporate standards and calibration laboratories and supported by NBS, are used to tie

the units embodied in test equipment to the

legal units. Table 6 lists these basic standards. Standards are arranged in descending

order of performance capabilities where more

than one are listed. Approximate accuracy

capabilities are expressed in parts per million (0.0001%) in parentheses.

In parallel with the hierarchical organization mentioned above, there are similar

technical chains of measurement traceability

from NBS standards to the end uses. Examples of these are to be seen in figures 2 and 3 which depict the traceability of ap- plied voltage measurements in the electronics industry and applied energy measurements

in the electric power area, respectively.

The dissemination of electrical units is generally accomplished in one of two fashions. In the traditional calibration method, the standard to be calibrated is taken

to the laboratory in which the standard used

to calibrate it is kept. It is then calibrated, and returned. Although this ap- proach has the merit of being easily managed

and is generally adequate in most situations,

it has a number of technical flaws. The

standard is not calibrated in the environment in which it will be used. Hence possible environmental effects tend to be overlooked. The same holds for the electrical

conditions of use. Checks are not made on the veracity of the measurement made in the

use of the standard; and no assessment of

the stability of the standard during the

physical transfer is generally made. Alternatively, the units may be disseminated by

using suitably tested transport devices to sample the quality of measurements being

made in the measurement chain. This latter

Table 6. Basic units and industrial standards

Unit of

DC voltage

DC resistance

DC resistance

ratio

Capacitance

Starting

Level

1.02 V

lO"* ohm

1/1

10 pF

Standards

Inductance 100 mH

AC voltage ratio N/A

AC-DC voltage N'/A difference

Power N/A

Energy N/A

AC current ratio N/A

Saturated standard cell enclosures . (0. 5) ; solid state reference devices (5), unsaturated standard cells (50)

Primary standard resistors (0.1-1); Rosa-type and other

intermediate standard resistors (1-15); resistance

transfer boxes and precision decade resistors (10-250);

resistive shunts (50) Hamon devices (0.02); precision resistive dividers (0.05);

standard volt boxes (5); potentiometers (10)

Fused-silica dielectric capacitors (0.4); gas dielectric

capacitors - 3-terminal (3-100); gas dielectric capacitors

- 2-terminal (50-1 ,000)

Air core standard inductors (200-2,000)

Inductive voltage dividers (0.1); instrument transformers

(100-300); high voltage transformers (100-3,000)

Mul ti junction thermal voltage converters (5-10);

Hermach-type thermal voltage converters (5-100)

Wattmeters (100-10,000)

Watthour meters (200-1,000)

Current transformers (100-300)

Numbers in parentheses are approximate uncertainties in ppm,

n can be any whole number between -4 and 14.

n
>>

T3

Q)C

01

to

«/) 03

(O

4-> $-o

CO c 0 (O 0 *l

Q_ 000(t3 'rJ (/I 10 1_ 4->

r <T

I/)

C

(_) c 0

<U (J 1_

d Q. 0 0 (O QJ

fO to <U 4-> 4J -a -o -a J- 0

00 c sl 0 (O >> (O O) >^+J 5-

C7> 0 4-> 0 (O (O c fo s- jr U 0 <a

s- Z3 -r- s- 0 -M 0 r- s: 0 0 <u 0 fO >

IS cC E 0 ct 0 Q

CO E +-> Q.

S- CL

(U + 1 I o

CM+ 1 ooI o o

LOo oI o+ 1 c

O)E

(U

s-

«o

(O

4-> ooo

to -o

-t-> t/1

DCo

(O • $- JU to

to co

•r—

fO

S- JH JD (O EOo o

-M (U O C

13 •!- TD —I O

SO>O

>»

4-> u

10

S- o

-a

to -a

i~fO oc

rO 0

4J

(O

$- XI •4->

•1

O)

(O E 0 CL

•1

s_«3 UJ

•r—

"r—X

13 <:

<u 0 od +-> 0 •r— s- S- Q 0

(O 0 >

-0 $- c

rO

-)-> IT)

M o

-a

10

+->

t- "o

<u > — -M I (O OJ o +-> E O •r- +J CDi— 1—

•rO I O >• O

CM

<U

s-

:3cn

•1- <uu . O) c: O to

i~ -o n -r- O =3 CO C3

Q to

S- >> >>

(U 1— O)

+-> CLi—

0) Q- 1-

X E Z3 to eC 0 0 CO to > '-^ X> •r— J- $- -0 M 0 -0 $- C O) 0 4-> C 0 <U -1- "O

SZ r— 0) x: 5 > •--

+-> 0 -M »-> 0 1— >

<1> >• 0 0) a. <u 5: Q. 2; —

Q

12
Electricity Division

Time & Frequency

Division

Time

1. Standard Cells

2. Potentiometer

3. Standard

Resi stors

4. Volt Boxes

5. Vol tmeter

Primary Energy Std.

(3 watt-hour meters)

Current Transformer

Voltage Transformer

Transport

Watt-hour

Meter

Field Standard

(Rotating watthour meter)

Instal led

meter

(sampl ing

Figure 3. Traceability of energy measurements
method is ioinewhat more complicated in terms

of data analysis and management and more

costly in labor, but gives a more realistic

picture of system performance. This approach

is now being used more and more for dissemination purposes, especially where high ac- curacy is desired for the dissemination of

the basic units between primary laboratories,

or in cases where a suspicion exists that a measurement process is in trouble.

Technical information is disseminated

throughout the system in the following ways:

(a) written calibration procedures,

(b) manufacturers' instruction manuals

and user newsletters,

(c) informal contacts between colleagues,

(d) technical papers published in the

open literature, and

(e) voluntary standards (previously discussed).

Most information is probably disseminated

through the use of published procedures.

Most government quality control contractual

requirements demand the establishment of a library of written procedures covering everything from data handling to instrument calibration. Such procedures are exchanged

throughout the segment of industry supporting the government through GIDEP, the Government Industry Data Exchange Program. Par- ticipation in this data-bank program is now mandatory for Defense Department contractual

suppliers. Procedures must be submitted at

a given rate by each participant for inclusion in a giant data bank. The bank is ac- cessible to all participants. (GIDEP is not confined to calibration information. Other

aspects include reliability data, instrumentation applications, etc.)

Many manufacturers include calibration

instructions as well as application instructions in the user manuals supplied with instrumentation. This is probably the second

major source of technical information in the

system. The others seem to be less signifi cant.

2.2.2.2 The Electronic and Electrical

Instrumentation Industry

The instrumentation industry [8,9] is the

only source of those measurement tools which

provide the foundation for the quality of

all manufactured products and, in some cases, provide the enabling means of their manufacture. Instruments are manufactured to measure every electrical parameter with accuracies ranging from those to be found in

standards laboratories (parts per million)

to five percent for analog panel meters.

Their use with transducers enables the mea- surement of other physical parameters, such

as temperature, strain, force, pressure,

resistance, etc., as well. Instruments can

be as simple as the dwel 1 -tachometer used to tune an automobile or as complicated as a system for the checkout of inertial navigators, employing dozens of separate pieces of

test equipment, capable of 0.005% accuracy

in some cases and completely under the control of a computer.

Measurement instrumentation and control

equipment enable the large volume, high

quality, and low cost mass production which

has made our high standard of living

possible. The ready availability of digital

computers as well as of reliable, accurate

instrumentation capable of being computerdriven has led to the increasing use of electronic process control systems in areas such

as the petrochemical industry to replace ex- isting pneumatic, hydraulic, or manual systems. Electronic systems have the virtue of

being able to respond much more rapidly - nearly instantaneously - to process changes

than mechanical systems and offer greater

flexibility in that process modifications

may be readily brought about through soft- ware rather than hardware changes. In addition, the use of digital logic makes

availabile a capability for decision-making

of a complex nature. Electrical measurements are necessary to the maintenance of this type of electronic

equipment as well as all others of a durable

nature

.

A representative list of electronic instruments used for calibration, maintenance,

testing, and analysis is given in table 7. Table 8 is a list of the major manufacturers

of basic standards and primary calibration

equipment in common use in standards laboratories in the U.S. It is not exhaustive.

14
Table 7. List of common instruments Table 8. List of electrical standards

manufacturers

Acoustic noise generators

Admittance meters

Ammeters

Amplifiers (over 30 types)

Analog-to-digital converters

Audio frequency analyzers

Audio mixers

Audio test oscillators

Automotive test systems

Bridges (17 types)

Calibrators (current, voltage,

oscil loscope)

Current sources

Data recorders

Decade boxes (capacitance, resistance)

Digital comparators

Digital filters

Digital-to-analog converters

Digital voltmeters

Distortion analyzers

Electronic integrators

Electronic micrometers

Electrostatic voltmeters

Fl uxmeters

Function generators

Harmonic analyzers

Hysteresis plotters

Interferometers

Instrument transformers

Multitester meters

Operational power supplies

Oscil loscopes

Peak power meters

Potentiometers

Reflectometers

Sampl ing vol tmeters

Tachometers

Telemetry modulators

Vibration meters

Voltage-to-frequency converters

Volt ratio boxes

Watthour meters

Wattmeters

Beckman Instruments, Inc. James Biddle Co. Electro Scientific Industries

Engelhard Industries

Eppley Laboratories

Peneral Electric Company

RenRad

Guildline Instruments Ltd.

Hewlett-Packard Company

John Fluke Manufacturing Company

Julie Research Laboratories

Keithley Instruments

Knopp Inc. Leeds and Northrup Company

Penn Airborne Products

Sangamo Electric Company

Ti ttex Victoreen

Western Electric Company, Inc. Yokaqawa Electric Works

Test equipment and instrumentation manu- facturers constitute a much larger segment

of industry (SIC Codes 3811, 3821, 3822, and

3825). Total estimated sales in these cate- gories for 1976, according to the Domestic

and International Business Administration,

U.S. Department of Commerce, were in excess of S7.7 billion [10]. Domestic customers

included every segment of industry using

high technology.

Electrical measuring instruments shipments were estimated to value $2.1 billion

in 1975 and are expected to increase to $2.4

billion in 1976 [10]. Test instrumentation

accounts for 60 percent of the output of

this SIC (3825). Low accuracy meters, used

in panels and switchboards, and portable

meters constitute 28 percent, and watthour

and other integrating meters make up the re- mainder. The test equipment industry is a high technology industry which is noted for

rapid exploitation of technological advances.

Some manufacturers spend as much as ten per- cent of their annual sales on research and

development [91.

The growing semiconductor market, in- creases in the complexity of components, and

their growing application to consumer products has generated an expanding market for

automatic test equipment for production line

quality testing and adjustment. Automatic

test equipment is increasingly being used by

semiconductor device users as well as manu- facturers. Digital instruments are rapidly

replacing analog equipment due to substantial cost reductions and the minimization of

reading error.

15
The instrumentation market is expected to expand over the next few years as manufacturers are spurred by the need to conserve

energy and costs and reduce pollution.

In the category of Engineering and Scientific Instruments (3811), navigational and

guidance instruments, and automatic pilots

for ships, aircraft, and space vehicles com- prised nearly one half of the industrial output. Thirty percent was composed of laboratory instruments and equipment. The remainder was composed of engineering apparatus for

meteorological, hydrological , geological,

civil, and mechanical engineering purposes.

Production of measurement and control instrumentation was expected to reach $2.8 billion

in 1976 [10]. The process control portion

of this industry is the portion to be con- sidered part of the electrical instrumentation industry. There is a high degree of

activity in this area spurred by manufacturers' demands for processes which are more

economical or efficient and which have re- duced energy consumption and environmental

impact.

Exports of all instrumentation are presently at the $60.1 million level [10], having risen sharply over the last two years.

Although the U.S. holds a strong lead in the most advanced instrumention, foreign competition is increasing. The recent increase

in exports is expected to moderate somewhat

in the future and imports are expected to increase slightly [9]. .

2.2.3 Reference Data / -

•

Some reference data, i.e., physical con- stants and other similar data, are generated

in the NBS and the academic portion of the

measurement system and used primarily by re- search scientists seeking to test and improve

physical theory. Examples of such data are measured values for Yp, the gyromagnetic

ratio of the proton, and e/h, the ratio of

electronic charge to Planck's constant [5,

11], both obtained experimentally at NBS. Recent accurate measurements of the speed of

light have made more accurate determinations

of the absolute ohm possible [3,11].

Although their use throughout the bulk of

the measurement system is limited, their determination has a fundamental impact on the

values of the basic maintained electrical

units and as a source of improved methodology

for monitoring the stability of those units.

Furthermore, much work has been done at NBS to supoly least-squares adjusted values

for the fundamental physical constants [12].

These values, internationally sanctioned by

CODATA, the Committee on Data for Science

and Technology of the International Council

of Scientific Unions, tie together all of

the remote branches of physics and are universally used by theoretical and research

physicists. Data of this type are disseminated by publication in the scientific literature.

A more widely used type of reference data

is that of electrical performance characteristics used by all design engineers. This

type of data is disseminated by publication

in various engineering and scientific handbooks, prepared by technical institutions

and private corporations, such as those given

in table 9. Data in these handbooks range from con- ductivity of wire, breakdown characteristics

("volt-time curves") for sphere gaps, and

Kerr electro-optical coefficients to recom- mended circuits for various applications.

The most universal of them are obtained as the result of experiments done in national

laboratories such as NBS, and in universities. Others, such as transistor perfor- mance characteristics, are published by semiconductor device manufacturers. All are es- sential to the efficient functioning of the

design engineer and the experimentalist. It is apparent that if these data were not generally available, each new advance in technology and each design of a new circuit would

come only after a long period of trial and error, measurement and experimentation.

2.2.4 Reference Materials

The direct role of reference materials in the Electrical Measurement System is limited

to two areas: those of eddy-current measurements of the conductivity of non-ferrous

metals and measurements of resistivity of

silicon used in the semiconductor industry.

The eddy-current technique is widely used in the aircraft industry and its metals suppliers as a non-destructive means of determining the heat treat of alloys, notably

those of aluminum and titanium. Such mea- surements are commonly made using eddy-current conductivity meters which actually mea- sure the change of inpedence of a probe,

driven at a certain frequency, caused by its

coupling with a conducting material. Such

meters are calibrated using small standard

samples (coupons) of metals manufactured

either by Boeing Aircraft Corporation or the

manufacturers of the meters. The conductivity of the coupons is generally determined

in terms of the legal unit of resistance

using dc measurement methods performed on rather large samples of materials which are

then cut up. However, dc measurements thus made are of

the average conductivity through the entire

metal piece and in one direction only. Eddycurrent measurements are localized in a small

16
Table 9. Sample sources of reference data for engineers

Source

Reference Data for Radio Enghieers

Handbook of Chemistri! and Thvsics

The Semicoyiductor Data Book

Formulas for Computing Capacitance and

Inductance, NBS Circular 594

Ajrierican Institute of Physics Handbook

Digital Logic Handbook

The Transistor anud Diode Data Book

Publ 1 sher

International Telephone and Telegraph

Corporation, New York, NY Chemical Rubber Publishing Co.,

Cleveland, CH Motorola Semiconductor Products,

Phoenix, AZ National Bureau of Standards,

Washington, DC American Institute of Physics, New York, NY Digital Equipment Corp., Maynard, MA Texas Instruments, Dallas, Yx

volume in contact with the probe and usually

limited to a shallow depth. Because of the

structure of most metal samples, (grain orientation, impurities, local strain, etc.)

the local conductivity can vary widely and

intercomparisons of eddy-current meters and

conductivity coupons have revealed some ra- ther large discrepancies in measurements

being made. Accordingly, NBS has been approached by a number of aircraft companies

to establish material standards in order to eliminate these discrepancies and to remove

the confusion which exists in this area. In 1977, NBS held a workshop in this area to identify the problems associated with these

measurements and identify other areas where

standards are needed. Plans have been made

and work is underway to establish national

standards of conductivity in the range be- tween 1?^ and lOO/r of the conductivity of

copper. Based upon this v/ork, eddy-current

conductivity standards or coupons of various metals will be made available through

the Standard Reference f^'aterials Program.

Standard reference samples of silicon are available through the Standard Reference

Materials Program to support the measurement

of the resistivity of semiconductor materials. This SRM results from work done by

the NBS Electronic Technology Division and

will be reported in that Division's impact

report.

2.2.5 Science and People

Electrical metrology involves the direct

application of principles of physics and

electrical engineering to the solution of

measurement problems. The role of physics

is most evident in basic metrology work; the

development of instrumentation and the as- sembly of sophisticated instruments into mea- surement systems. The major contribution of

the measurement system to its undergirding

science and technology is to provide a com- mon means of communication, a universal

technical language without which the transfer of knowledge and technology within the

system would be impossible. Without such

data transfer, the advanced technological

society we find in the United States would

not be possi bl e. There is heavy involvement of professional societies in the Electrical Measurement System. They provide a means of informal and formal communication of knowledge

throughout the system through their meetings

and publications. The following is a list

of these societies:

1. Institute of Electrical and Electronic

Engineers; f^roup on Instrumentation

and Measurement

2. Instrument Society of America; Metrology

Division

3. Precision Measurements Association

4. National Conference of Standards

Labora tories

5. American Society for Quality Control

6. American Society for Testing and

Material

s

7. American Physical Society

8. IEEE Groups on

a. Automatic Control

b. Biomedical Engineering

c. Circuits ?i Systems

d. Communications

e. Industrial Electronics and Control

Instrumentation

f. Reliability and Maintainability

9. IEEE Power Engineering Society

The first four of these are groups dealing directly with electrical metrology and

its applications. Their members produce

document standards, engage in measurement

activities, such as round-robins, and, most

importantly, communicate and encourage com- munications by means of meetings, colloauia,

conferences, seminars, and oroducing various

17
publications. The rernaining are rrore peripherally involved in that their activities

are supported Hy the system and they provide

the system with backup technology and information.

The major electrical metrology publications commonly used in the U.S. are:

Metro login

IEEE Trancaations on Inc fomentation

and Measurement

IEEE I'l-ayisactions on Power Apparatus ami

i^l-j stems

Measurements and Data

Instrumentation Teahnology

Review of Scientific Instruments

All feature technical papers on metrology

in various application areas or sectors of

the measurement system. More specific, detailed information on specific calibration

problems is disseminated through documented

calibration procedures as discussed previously.

Measurements people generally fall into one of five categories; physicist, electronic engineer, electrical engineer, statistician, or electronic technician. Those in the

first four receive their professional training in universities and colleges. Electronics technicians generally receive their education as the result of military service and

occasionally through correspondence or technical schools. All can improve or augment

their background through the many seminars

and short courses in metrology and electronics offered around the country. The

field of metrology is fortunate in having a very high degree of dedication on the part

of its workers.

2.3 Realized Measurement Capability

The graphs on the following two pages

represent measurement accuracies available

throughout the measurement system. It must

be understood that they represent an over- simplification of an extremely complex interacting set of parameters. For example, the

question of a specified time frame in which

a measurement is made has been ignored. En- vironmental and power line effects have been

likewise ignored. The fact that a good me- trologist can coax performance far in excess of manufacturers ' specifications from

measurement instrumentation, given appropriate resources or complete freedom of

choice regarding methodology, is not represented. In essence, the graphs represent a compilation of manufacturers' specifications

and known behavior traits of populations of

standards in common usage. In the interest

of brevity, ac quantities have been shown

at one freauency, 1 ODD Hz in the case of capacitance and inductance, 60 Hz in the case of

energy and current ratio, and 10 kHz in the case of rms ac voltage.

The instrumentation available is adequate

for the fulfillment of static measurement

needs at the present time in most cases. Re- cent evidence, however, indicates the possible existance of a hitherto unsuspected

loss of measurement accuracy as a result of

high accuracy electronic instruments having

been physically transported, either to be

calibrated or for use elsewhere. The problem is presently being investigated.

Another problem area, whose importance is emphasized in liaht of present economic con- ditions, is the cost of maintaining an instrument in calibration. Many new instruments

are being designed with self-checking features

to permit extension of calibration intervals

or the elimination of periodic calibrations.

A method of testing the verity of self-test

features is desperately needed.

More and more measurements are being made

by automatic test systems; assemblies of offthe-shelf commercial instruments, customized

apparatus, and interconnecting circuitry,

all controlled by computer. Generally such

systems have some self-test capability which

provides a functional check and perhaps a limited calibration using an internal standard as a reference. The self-test capability must be periodically augmented by

calibrations. Usually this is accomplished

by removing critical pieces of apparatus to

a remote laboratory for individual calibrations which are assumed valid when the

system is reassembled. Rarely are systems

calibrated as systems, despite the fact that,

because of temperature, interface, and electrical grounding and shielding problems,

they tend to be somewhat more than the sum

of their parts. The major restraining factors of systems calibration seem to be lack

of acceptance of the approach by military

and other government inspectors and the

nonavailability of hardware specifically

designed for the purpose. There does at present seem to be a growing awareness of

the advantages of this methodology.

There are a few areas in which present

measurement technology has fallen behind re- quirements. There is a problem, previously

discussed, regarding the use of samples of

nonferrous metals as conductivity standards

for nondestructive testing purposes. An- other area is that of ac voltage measurements throughout the audio frequency range.

Improved measurements in this area are needed to support modern ac voltage measurement

equipment. A third area is that of the mea- surement of impedance (capacitance) in the

frequency range between 10 kHZ and 100 kHz.

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18
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The communications industry is in a trend

toward increasing carrier frequencies into

this range and have requested calibration

data there.

The energy crisis has created some high

voltage measurement problem areas. Because

of the limited supplies of petroleum, electric energy will comprise an increasingly

larger share of all energy consumed. Efforts

are underway, sponsored by the Department of

Energy and the Electric Power Research Institute, to develop more efficient and safer

ways to transmit electric power. These efforts require new or improved methods and

standards for measurements of impedance,

ratio, voltage, and current at voltages as high as 1.2 million volts. They are needed

for the evaluation of dielectric losses in

insulators at cryogenic temperatures under

high voltage conditions, for measurement of

electric fields caused by ultra-high voltage

transmission lines (to test biological effects), and for the measurement of high voltage transient signals to test their effects

on lines, measurement apparatus, switchgear,

etc.

As noted, the entire section thus far has

concerned only static measurements, measurements in which time is not a critical factor.

However, the timing of a measurement is increasingly important for two reasons. Be- cause of the ever-increasing complexity of

electronic modules, components, instruments,

and systems, more and more testing is re- quired for quality control purposes. As testing is the factor which limits the production rate of electronic goods, increasing

emphasis is being placed on "thruput".

Secondly modern electronic circuitry is more usefully characterized in terms of

transient responses to changing input con- ditions. This leads naturally to the need

to measure rapidly varying parameters, to be concerned with wave shapes as well as integrated energy content. This can only be

done by "sampling" or measurements at high

speed.

In order to increase the speed at which

measurements are made, a whole new world of

automatic testing has evolved. Analog-todigital converters with microsecond measurement times are computer-controlled and

switched in systems which permit thorough

testing of complicated circuits in relatively

short time.

Along with this evoluation has come a degree of chaos. The conclusions of a re- cently-held workshop on "Critical Electrical

Measurement Meeds and Standards for N'odern Electronic Instrumentation" ri3] are:

(a) There is a need to introduce time as

a measurement parameter as a result of re- quirements of automatic test and control

systems.

(b) A host of new parameters have re- sulted from the application of automated

systems to the production line, parameters

for the measurement of which there are no standards, techniques, or even a common

terminology.

(c) A need for a new or higher accuracy

measurement has resulted from recent work

at the leading edge of measurement technology in electronics.

From these, a number of critical, specific areas needing immediate attention were

indicated. Among them were:

(1) capacitor and resistor characterization under pulsed conditions;

(2) dynamic performance characterization

for modern signal conditioning and data con- version devices, such as aperature times of

sample-hold amplifiers, resolution-time

product for analog comparators, iitter error of digital-to-analog converters, etc.;

(3) characterization of settling times

for precision sources and measurement devices, for example digital voltmeters and

programmable power supplies;

(4) transport standards for system performance validation to be used as a basis

for Measurement Assurance Programs;

(5) effects of dynamic loading on sources

(6) prediction of long-term performance

of components and devices from short-term

behavior, for example, relating output noise

and device reliability;

(7) improved transportable dc standards

based upon solid state technology which would

be immune to short-circuit or loading damage,

not materially effected by temperature fluctuation, and perhaps at more useful levels

of voltage, current, or resistance than are present standards;

(8) measurement of dielectric hysterisis

in capacitors and other components; and

(9) generation of nonsinusoidal , high

crest factor precision signals for true rms

cal ibrations.

The workshop was attended by 2^ participants who represented a variety of industrial

and government organizations. The abstract,

preface, and list of participants from the

final report of the workshop (published as DBS Technical Note 865) are appended [Appendix C].

21
2.4 Dissemination and Enforceirent Network

2.4.1 Central Standards Authorities

The Bureau International des Poids et Mesures (BIPM) is the supranational authority

of the electrical measurements world. In its

laboratories are housed artifacts embodying

international standards of voltage and resistance. At three-year intervals, BlPf undertakes the i ntercompari son of transportable

standards of voltage and resistance from the

major national laboratories of the world and

its own international standards. The published results of these intercomparisons are generally accepted as quantifying the differences among the units of the participating

countries. BIPI^ also sponsors international

exchanges, such as a present round-robin intercomparison of transportable capacitance

standards. Such devices are measured at various national laboratories and the results

submitted to BIP!^. At the conclusion of the

experiment the results are published.

The Consultative Committee on Electricity,

to which the Chief of the Electricity Division, NBS, is a delegate, advises and re- commends courses of action to BIPM in matters dealing with electrocal metrology.

The National Bureau of Standards is the

delegated legal authority for electrical mea- surements in the United States. Public Law

617, 81st Congress (21 July 1950), states in

Section 12:

"It shall be the duty of the Secretary

of Commerce to establish the values of

the primary electric and photometric

units in absolute measure, and the

legal values for those units shall be

those represented by, or derived from

national reference standards maintained

by the Department of Commerce."

Most nations with modern technological ca- pabilities have organizations performing the

function of maintaining legal electrical

units. Aside from minimizing the effects of

discrepancies between legal electrical units

on export trade, the major interaction be- tween these laboratories and the Electrical

Measurement System is to provide an international redundancv in the realization of the

absolute electrical units. Parallel experiments, perhaps with differing approaches and

performed under different roofs, offer the

best opportunity to eliminate the effects of

unidentifiable systematic errors from experimental results. Since adjustments to units are made as the result of these experiments,

redundancy in them is of great importance.

2.^.2 State and Local Offices of Heights

and Measures

The Electrical Measurement System only

interacts with the weights and measures

field to the extent of providing the basis

for design and maintenance of any electronic

equipment used in that field.

2.^.3 Standards and Testing Laboratories

and Services

Three kinds of laboratories provide mea- surement services to the Electrical Measurement System. Standards laboratories are those laboratories which can provide for the

calibration of electrical standards with

accuracies within an order of magnitude of

those offered by MBS, They may well be, and

usually are, capable of providing calibration services for nearly any type of instrument over any range of parameters and at any accurac.v level up to those of the basic

standards. A calibration laboratory, on the other hand, calibrates and repairs test equipment and production-line equipment of more moderate accuracy. The third type of

laboratory is a testing laboratory. Although it may offer services similar to the

other two, it is characterized by facilities

for environmental, safety, and performance

testi ng

.

The first two types can be either the

basic measurement laboratory of a large

corporation, the service repair department

of an instrument manufacturer, or a small

private company dealing only in those services mentioned. Standards laboratories

tend to be of the first two varieties,

whereas calibration laboratories tend to be

of the third.

Within the electric power industry one

can make a distinction between the utility

and manufacturing sectors. The major utility companies each operate a kind of laboratory which can be characterized as a mixture of the standards and calibrating

laboratory with some functions of a testing

laboratory, l^'ith respect to accuracy, the

most demanding requirement is for watthour

meter and instrument transformer calibration. For these functions the laboratory

maintains high quality standards, with ac- curacies within an order of magnitude of

those of MBS standards. The same laboratory usually also calibrates and repairs

test instruments for the company. Finally,

the laboratory may have jurisdiction over

the acceptance tests of all incoming and

in-service watthour meters and instrument

transformers. The latter is a function of

a testing laboratory.

22
Within the nanufacturing sector, the typical laboratory can be classified as a testing facility employed in Quality control and

performance testing of a company's products.

This laboratory rray obtain standards services

from a standards laboratory elsewhere within

the company, may occasionally ask for fiBS help, or may rely on traceability through the

supplier of the measuring instruments.

Appendix D contains a list, drawn from the sources indicated, of standards and calibration laboratories v/hose services are available to extra-company organizations. It is not exhaustive. The 13P laboratories listed,

along with others of their kind and the major

military and corporate laboratories supplying

services only within their own and subcontracting organizations, provide the traceability skeleton supporting the body of electrical measurements in this country.

Of federal laboratories other than NBS,

apparently only three offer electrical calibration services on a fee basis. They are:

Ca) U.S. Army Electronics Comand,

Ft. Monmouth, NJ

(b) Naval Air Rework Facility,

Norfolk, VA

(c) Navy Eastern Standards Laboratory,

Washington, DC

Other military and NASA laboratories will

generally provide a contractor with services

if they are not elsewhere available, or if

it is to the advantage of the government.

All the above-mentioned and those included

in the referenced appendix are laboratories

having services available to outside organizations on a fee basis. No mention has been

made to this point of the remaining group,

namely, those laboratories which provide services only internally, to their own organization. Of the 222 standards laboratories

listed in A Directory of Standards Laboratories [14], 164 have dc and low frequency

capability, and only 65 choose to make that

service available to outside firms or organizations.

An analysis v/as made in 1973 of NBS calibration clientele for the purpose of determining, among other things, the general magnitude of the Electrical N'easurenent System.

A representative sample of clients' names was classified by prim.ary SIC code by Dun and

Bradstreet. The resulting list of code numbers was filtered to remove obvious measurement-void categories. Dun and Bradstreet 's data base, which contains information on over

3 million I'.S. companies, was then searched

to provide information on all companies in

the relevant group with numbers of employees

in excess of 25. Information was provided

on 12,865 companies. Even though this figure

is not an accurate count of measurement-i nt ensive organizations due to the way the individual SIC code numbers are assigned, it

is a good protrayal of the extensi veness of

the measurement system. In fact, the figure

is on the low side because companies engaged

in routine measurements without rigid traceability reauirements are not included. Efforts to sample this grey area of the sys- tem have been minimal due to financial constrai nts

.

For companies not having rigid traceability reauirements, the measurement system may

flow through the company via the electronic

maintenance shop or the outside organization

which performs this function for them. Many

of the laboratories in Appendix C also perform repair functions.

For organizations which must maintain

traceability because of contractual or legal

reauirements, the flow of electrical units

through the system becomes more stylized.

The flow of the electrical units through

such an organization is depicted in figure

5. The corporate or primary laboratory may

receive its units from NBS or from any outside laboratory. It is repsonsible for the

most accurate standards in the organization.

The actual organizational relationship of

these various components varies from corporation to corporation. An extremely large

corporation, such as Boeing Aircraft, may

have a corporate standards laboratory which

serves as a single tie betiveen NBS and all

of its calibration laboratories. Other

large companies such as Honeywell and IBf

have a standards laboratory at each location

and many such laboratories have standards

calibrated by NBS. Other corporations such

as 3f' and Peneral Electric do not make the

use of any particular structure mandatory.

Each operating division is autonomous and

may pursue its ouality assurance program

quite independently.

In smaller organizations the standards

and calibration facilities are usually combined. Occasionally even the maintenance

shop is in the same organization, if not in

the same room. These basic elements are

alv/ays present, however, even if not struc- turally distinct. Take the case, for ex- ample, of a small company employing about

ppo persons, which is concerned with the

manufacture of temperature and air speed

transducers and allied instrumentation.

They have need of extremely accurate re- sistance standards because of their temperature work. However, their dc voltage re- ouirements are not as stringent. They have

their resistance standards calibrated at

NBS, but their corporate voltage standard is

a digital voltmeter calibrator which is caliPrcted for t'lem periodically another com- pany in the area.
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24
Representative organizational charts for

two large corporations and the U.S. Air

Force are to be found in Appendix E. The specific structure of any given part

of the [feasurement systerr, is a function of

the technical requirerrents of the end product, the legal ot 1 ir-ations of the orranization, the financial resources available, and

the standards, apparatus, and test enuiprrent

available to meet the ultimate measurement

renui rements

.

2.4.4 Regulatory Agencies

Table 10 gives the titles of regulatory

agencies and agency categories impacting the

Electrical Measurement System.

Table 10. Regulatory agencies and agency

categories

Federal Government

1. Nuclear Regulatory Comnission

2. Environmental Protection Agency

3. Federal Aviation Administration

4. Food and Drug Administration

5. National Highv/ay Traffic Safety

Administration

6. Occupational Safety and Health

Administration

State Governments

State Public Utility Commission

The Nuclear Regulatory Comnission (NPC)

has the function of being Federal v/atchdog over radioactive materials in this country

for both security and safety purposes. They

have issued regulations v/hich compel the formation of quality assurance programs in nu- clear power plants and fuel reprocessing facilities. Regulation 10CFR50, "Licensing of

Production and Utilization Facilities" has

an Appendix B entitled "Quality Assurance

Criteria for Nuclear Power Plants and Fuel

Reprocessing Plants." This Appendix and

corresponding Regulatory Guides call for

periodic calibration of all measuring equipment. The result of such regulations is the

establishment of standards and calibration

laboratories at all nuclear use and processing sites to ensure the quality of measurements at such sites.

The Commission is presently in the process

of revising these regulations to improve

their clarity. The National Bureau of Standards is anticipated to be called upon to provide technical assistance in this activity.

The Environmental Protection Agency (EPA)

has an indirect effect on the Electrical

Measurement System. The instrumentation,

which is required by the agency and by industry to jnonitor pollution, is used mostly

for analytical and accoustic measurements.

Sales of such instruments are increasing at

a rapid rate, sparked by large increases in

federal and private research and development

in this area ro]_ jh-js equipment is basically electronic in nature and, as such, re- quires maintenance, if not electrical calibration.

The Federal Aviation Administration (FAA)

is responsible for all air travel safety in

the U.S. It regulates the communications

and navigation ecuipment used in the air

travel system. A measurement laboratory facility is maintained in Atlantic City, NJ,

which supports a network of navigation aids

such as radar systems, landing systems, and

beacons at airports throughout the country,

in addition to a test facility for avionics

on the Atlantic City site. In addition, the

FAA is now in the process of implementing a program for the periodic recall and calibration of all test equipment in its system.

This new calibration structure may be ultimately supported by the standards laboratory

of the FAA maintenance and repair depot in

Oklahoma City.

The Food and Drug Administration, as was pointed out previously, is expanding into

the regulation of medical devices. Aside

from the proposed reaulatory program for new products described in Sec. 2.2.1.1, they are involved in a program to ensure safety

through the proper level of application of

voltage to x-ray tubes. It was found as a result that the voltage dividers used for

measurement of cathode voltages were poorly

calibrated at best and improper x-ray dosages resulted. Bureau of Radiological

Health support resulted in the establishment

of a calibration service for such dividers

at NBS. The National Highway Traffic Safety Administration is responsible for enforcement

of the application of safety standards to automobiles. The group monitors the whole

field of automobile safety testing. Use is made of Society of Autmotive Engineers'

specifications to detail methods to be followed in the testing and to prescribe reouirerr.ents for quality assurance. Periodic

test and calibration of measurement instrumentation using standards traceable to NBS

are features of SAE Standard J21b. Manufacturers are required to abide by its provisions . The Occupational Safety and Health Administration generates job-related safety reg- ulations. Its major impact on the Electrical

25
Measurement System is its requirement that

certain devices be safety-tested in accredited laboratories. That requirement is ex- pected to be the forerunner of many future

requirements for laboratory accreditation

programs. None of the methodologies yet

proposed embodies a valid scheme to ensure

the proper behavior of standards, instruments, and systems on a continuous basis,

either through careful monitoring or any

other means. A real need exists for a technically-valid scheme for accreditation.

State Public Utility Commissions, in addition to regulating the rates charged consumers of electric power, regulate the sys- tem by which energy transfer is monitored

to determine total user costs. Watthour measurements are used to quantify

energy distributed within the power system

for metering purposes. The electric power

companies are generally required by the

Public Utility Regulatory Commisions in individual states to supply users with watthour meters accurate to within Tl.. Refunds

are required for overcharges if the meter

regulation is found to be in error — faster

than nominal — by more than 2°-. While power

companies are entitled to recompense from

users should the meter err in their favor,

they generally do not bill such users be- cause of the bad publicity which could result. Because of this situation, power companies typically calibrate new watthour meters with an uncertainty of 0.1-0.2 %. [Measurements at this relatively high level of

accuracy also permit new meters to be inspected using sampling techniques, thus

avoiding the large amount of work required

to inspect 100% of the incoming lot. Be- cause this practice is common in the power

industry, meter manufacturers must also use strict measurement tolerances.

Installed meters are generally recalibrated throughout the industry. However,

there is no industry-wide established interval between calibrations. This interval

ranges generally from five to fifteen years

and in most instances is done on a sampling

basis with 100°/ recal i bration only being

performed on the basis of poor results from

an initial group of tests. These measurements are made with the same uncertainty as are those on new meters.

Of all quasi-regulatory activities, procurement regulations governing suppliers of

the Department of Defense and the National

Aeronautics and Space Administration have

the greatest impact on the measurement system. The present hierarchical system of

laboratories, accuracy needs at the primary

standards level, and the generation of use

of detailed calibration procedures all stem from the enforced application of flL-C-

^5662a, MIL-Q-9P59a, NIL-I-45208a , and the

equivalent TASA regulations, all detailed

previously.

2.5 Direct Measurement Transactions Matrix

2.5.1 Analysis of Suppliers and Users

The organizational input-output matrix in

Figure f is a portrayal of the present magnitude and importance of measurement tran- sactions among various segments of the economic system. Each entry in the array gives

the magnitude, role of changes, import, adequacy, and type of transaction according to the code in Figure 7. An "X" as a particular entry indicates that the transaction was excluded from the study for some reason. Entries of "0", "X", or "?" require no further information for that transaction. It must be remarked that the matrix is only a qualitative portrayal. The uncertainties

in each ranking factor are high (±2) as it

is difficult to quantify relationships such

as quantity or volume in the context of various sizes and technical contents of industries. The general approach taken was that

a measurement capability could not cease to exist, since in that sense, the "Importance"

entry would be 4 by any rational consideration for each transaction. In addition,

those industries which require measurements,

instrumentation, and standards closest to the state-of-the-art" naturally are more familiar to the authors and received more attention during the course of the study as they are the most likely source of measurement problems.

2.5.2 Highlights re Major Users

Although virtually every segment of man- ufacturing depends to some extent on the

ability to make electrical measurements,

major users of the measurement system have

a very stringent need for an accurate mea- surement capability. These are the aero- space industry, the calibration and repair

industry, civilian agencies of the Federal

government, electronic component manufacturers, computer manufacturers, the De- partment of Defense, the instrumentation

industry, the power industry, and research

institutes. It should be understood that

technical measurement problems to be found

in this system are generally not unique to

a specific segment of industry in the SIC

sense. Rather they are generally associated with a broad class of activity such

as instrument maintenance or quality control of electronic products and accordingly

are not belabored in this section. Pressing

problems which are industry-peculiar are mentioned

.

26
DIRECT MEASUREMENTS

TRANSACTIONS

MATRIX FOR

Electrical Quantities

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Documentary

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Figure 6. MATRIX

27
A

A. Volume or quantity of transaction

0 - Trivial (other entries not needed)

1 - Minor

2 - Moderate

3 - Above average

4 - Major

X - Excluded from study

B. Importance

1. Convenience; not essential

2. Economically important

3. Legally required; no alternative source

4. Absolutely essential

C. Adequacy of Transaction

1 . Under control

2. Marginally adequate

3. Deficient, but useful

4. Out of control; totally inadequate

D. Rate of change of transactions

1. Declining volume (negative)

2. Stable (0)

3. Growing (+)

4. Explosive growth (very +)

E. Type of transaction

A. End use measurement data (specifications, etc)

B. Other measurement services (calibrations, etc.)

C. Measurement instrumentation and software

D. Measurement "How to" information

E. Measurement requirements information

F. Legal performance specifications

Figure 7. Code for transaction matrix

28
Aerospace (SIC Codes 3721 , 3724, 3728, 3761,

37P4, 3769, and 36P2). The aerospace industry is that segment of manufacturing which

produces space vehicles and aircraft and

their supporting electronics systems for

both military and civilian applications. It is a high technology industry (engineers and

scientists employed, 161,000) which makes ex- tensive use of electronics in the develop

ment and manufacture of its products, and es- pecially, for their weapons and guidance

systems. The industry is a large one, with

estimated sales of products and services in

1974 of $20.9 billion of aircraft and parts,

$9.6 billion of electronic systems support

equipment, and S5.8 billion of guided missiles and space vehicles [9]. Estimated total sales (1976) are $35.7 billion with an estimated electronics content in excess of

$20 billion. The estimated exports value of

aerospace equipment for 1976-is '^7.6 billion,

the third consecutive year that this industry's exports have exceeded $7 billion. This

industry embodies 2,107 establishments and

employs about 928,000 workers [10].

The primary impact of this industry is upon our national defense. Slightly over

ten percent of the aircraft produced were

sold to the Department of Defense as were

all guided missiles. These products are vital to the national security. Important sec- ondary benefits have come from this source. Consumer electronic products have been revo- lutionized by such spin-offs from the aerospace industry as monolithic large-scale integrated circuits whose low cost, reliability, and small size per unit function have

permitted the production of quartz crystal

watches, pocket calculators, and miniature

radio sets at exceedingly low cost.

An increasing portion of the output of

the electronic systems component (SIC Code

3662) of this industry is being consumed by

civilian-oriented commercial and industrial

firms. This is due to the need in industry

to make more use of digital data transmission, automated process and quality control,

and telecommunications to offset rising labor

costs and lower profit margins. Such areas

as satellite communications systems, data net- works, land-mobile radio communications, and

interactive, broadband cable communications

systems contribute heavily to this increase.

The electronic systems component is an area in which exports are expected to rise

sharply, 23'/, from 1Q75 to 1976. This is largely due to increased consumption in the

developing nations and, particularly, the

oil-producing nations of the P'iddle East. These countries, particularly Iran, Saudi

Arabia, and Indonesia, are attempting to develop their industrial bases in the avionics,

industrial, electronics, and communications

areas, in addition to increasing their military sophistication [10]. Exports in this area are expected to increase for the next

five years.

Electrical measurements in the aerospace

industry are used to characterize electronic

circuitry of all types, both for the assurance of quality and compatibility in manufacture and for maintenance while in service.

Accuracy requirements for so-called end mea- surements are quite high (as high as 10 ppm,

in some cases) due to the sophistication and

precision of guidance and weapons systems.

Since nearly all companies in this category

are contractors or subcontractors to the De- partment of Defense or to the National Aeronautics and Space Administration, the industry is subject to the provisions of the regulations used by these government agencies to assure quality in the systems and vehicles

procured. The concepts there outlined are instrumental in making the accuracies re- quired of an individual corporate calibration

support structure quite high.

Measurement problems faced by the aero- space industry are as follows:

(a) to reduce the cost of quality control

efforts in the face of a slightly deflated

market while adhearing to DoD and NASA re- quirements and regulations [10,13,15]; and

(b) measurement problems inherent in the

use and support of automatic test equipment,

such as those resulting from failure to calibrate under use conditions (e.g., making dynamic use of A-D converters which have been

calibrated statically) [15,16].

Calibration and repair of test equipment

(SIC Code 7393) . There is a small industry

in the U.S. having to do solely with the

calibration and repair of instruments, test equipment, and standards. Most companies

involved in this activity are quite small,

having annual incomes of less than $500,000

and employing less than 25 people. These

companies supply calibration and repair ser- vices to a variety of industries, such as small component manufacturers, transducer

makers, small electronic job shops, and

other companies whose calibration needs are

so modest that the establishment of an internal capability would be unduly costly.

(Such service is provided also on a fee basis by the corporate standards laboratories

of many large corporations. See Appendix D.

)

Equipment used by such companies ranges

from state-of-the-art standards and calibration equipment to older test equipment of

relatively poor accuracy. This results in a wide range of capabilities being available,

from the state-of-the-art to meter accuracies, that is, three to five percent. In

29
most cases the capability is equal to the

job performed. Problems related to electrical measurements in this industry seem to be

logistical in nature. Lack of facilities

for training, poor communications of technical data, increasing costs of publications,

and an increasing shortage of experienced

technicians are a few examples.

Civilian agencies of the Federal government

(SIC Div. 1). Those civilian agencies which

have or support (as opposed to require) an electrical measurements capability are as follows: Federal Aviation Administration,

Bureau of Reclamation, Energy Research and

Development Administration, National Aeronautics and Space Administration, Tennessee

Valley Authority, and National Oceanic and

Atmospheric Administration. FAA activity

was covered in Sec. 2.4.4. The Bureau of

Reclamation operates Hoover Dam and leases

power generated thereby to five regional

power companies. The organization has a standards laboratory that supports all of

the maintenance and power monitoring equipment on the site.

The Department of Energy (DOE) has a con- tracted primary standards laboratory in Albuquerque, NM, run by the Sandia Corporation, which is responsible for supporting and

assuring quality of measurements and contractural compliance with calibration requireemnts at each of the DOE field sites. The

National Aeronautics and Space Administration

(NASA) maintains a large number of standards

laboratories, one at each of its major centers and tracking facilities. NASA has an extremely large test equipment inventory

which is used to support space electronics,

its computer network, communications equipment, tracking systems, and aircraft. Many

of these laboratoies are staffed by contractors but the agency owns all of the equipment.The Tennessee Valley Authority laboratory

at Chickamauga Dam, TN, supports the power

monitoring equipment and electronic maintenance areas at that facility. The National

Oceanic and Atmospheric Administration supports the test and measuring equipment it uses in its investigation of undersea and

atmospheric phenomena by maintaining a standards and calibration facility at the Navy

Yard Annex in Washington, DC,

The social impacts of these agencies are wide-ranging. The Department of Energy

plays an ever more important role in the

search for means of alleviating our enerqy

shortage. Since it is a highly technical en- deavor, the use of measuring apparatus is heavy, and electrical measurements, especially those at high voltages, are of prime

importance. NASA is concerned not only with

space ventures but also with air transportation problems. Technical spin-offs of its

programs have resulted in the creation of

whole new technologies such as integrated

circuit technology.

Electronic components (SIC Code 3P7). The

industry employs about 359,000 people in about 2,500 establishments. The industry's

gross sales were 510 billion in calendar

year 1975, and are projected to exceed Sll billion in 197P [10]. Exports in this field

are at the Si billion mark and increasing

rapidly; up 23"' from 1974 to 1975. It produces such components of electronic equipment as resistors, capacitors, inductors,

diodes, transistors, integrated circuits,

tubes, and rheostats. By doing so, the industry provides versatility and cost effectiveness for every electronics-intensive industry such as those involving the production of automotive electronics, communications equipment, instrumentation and process

control equipment, etc.

['"easurements are vital to this industry

for both product Quality control and development of new products. The biggest measurement problems faced here are those concerned

with the proper calibration of very highspeed component testers. Such equipment is used to test large numbers of resistors, ca- pacitors, or other components at a high rate

of test. Even more importantly, complex integrated circuits must be thoroughly tested

in a short time frame. The time taken per

measurement is generally much shorter than

the time per measurement allowed in the calibration process, and for that reason the

calibration data may not be valid when the

tester is used on the production line.

There are a few problems having to do

with the state-of-the-art in measurements.

For example, solid-state device manufacturers are generally convinced that some of the

voltage reference devices they produce have

stabilities in the sub part-per-mi 1 1 ion (ppm)

range over the short-term and long-term (a few weeks) may be as stable as 1 or 2 ppm.

Few, if any, of these same manufacturers,

however, have a measurement capability adequate to determine this. Such capability

would mean a cost savings to industry as a whole because if these devices are indeed

capable of such stabilities, more accurate

instruments could be built and instruments

being built at present accuracies would re- quire less frequent calibrations and possibly less maintenance. Even if the refer- ence devices were not found to be as stable,

an improved measurement capability would re- sult in the ability to determine their sta- bility with fewer measurements taken over a shorter time span. Manufactured devices

30
could thus be much more easily categorized

and sorted. Similar problems exist in the

scaling processes for other units such as resistors.

Computer manufacturers (SIC Code 3573).

Sales of the computer industry were SIO.^

billion for 1975 and are estimated to in- crease to 51 2.1 billion in 1976 TlO]. This

rapidly growing industry (current growth

rate is about 14 per year) is estimated to have 179,000 employees. Its output products,

computers, large and small, and peripheral

equipment, are being used more and more throughout our society. They are used as ac- counting machines, problem solvers, process

controllers, navigation aids, machinery con- trollers, and in nearly every other situation where decisions trust be made and action

taken on the basis of numerical data. The

advent and continuing improvement of the

ipinicomputer, a small, inexpensive, and re- liable computer, and the microprocessor, a computer on a chip, have made the tremendous

power and capability of the computer available to virtually every segment of industry.

Small scale processes are being automated at

a very rapid rate, thus providing some offset to the ever-rising cost of labor in this

country.

Since most computers are electronic, electrical measurements play an important role

in their manufacture. Each component that

is received is checked to its specification

at most companies. Testing is done at each

stage of the assembly of such a device. The

equipment used for all such testing must be

maintained and calibrated and m.ost large com- puter companies have corporate standards and

calibration laboratories to perform this

function. Electrical measurement problems

in the computer industry are related to the

use and support of the automatic test sets which perform the quality assurance function.

Some problems result from applying static

calibration data to dynamic testing situations. A particular problem of great current interest results from the giant number

of measurements required to test a digital

circuit to an adequate degree. Even if it

is solved, however, there will be increasing

need, as semiconductor components become

faster responding and more complex, to make

measurements of both digital signal response

and dielectric properties of components at higher speeds and with greater reliability.

The state of technology is pushing the few

standards which do exist in this area. An- other problem area is the measurement of imoedances, especially inductors, in the frequency range between 10 kHz and 1 MHz.

The Department of Defe-'se. The Department

of Defense is very heavily involved with

electronics in communications, weapons, guidance, and navigational systems. The Department will have spent S2.6 billion for re- search, development, testing, and evaluation

of such eauipment and Si. 61 billion for the

procurement of electronics systems for FY 75. Total spending for FY 75 on electronics products as estimated by the Department of De- fense is $9.6 billion [9,10]. Assuming a five-year lifetime of electronics equipment

in the military, using marketing data for

the past five years such as surveys performed annually by Electronics magazine, one

can calculate a S6 billion inventory of

equipment which must be maintained. This is

done with a huge inventory of test equipment

supported by a hierarchical laboratory sys- tem in each of the four services. To illustrate the magnitude of the problem, the 1972

edition of Air Force Technical Order

33K-l-inn lists by part number over 28,500

individual items in the inventory requiring

calibration periodically. In excess of sixty percent of this inventory requires electrical measurements [17] for its support.

The Department of Defense is the largest

single consumer in the country and, accordingly, wields a trememdous impact on the marketplace. Technical spin-offs from its programs, much as is the case with NASA - who,

for example, are credited for the accelerated development of large-scale integrated

circuit technology - have served to advance

the technology base of our society.

The Department maintains a system of inspectors in various organizations (Defense

Contract Administration Service; Air Force,

Navy, Army Plant Representative Offices;

etc.) to ensure compliance with the calibration and quality assurance providions of the

procurement specifications listed in Sec. 2.2.1.1. In this way, it influences the na- ture of the measurement system in a large

segment of industry.

As mentioned before, the main use of electrical measurements vn'thin the Department of

Defense is to maintain its extremely large

inventory of electronic systems and equipment and the test equipment used to support

it. The major current problem areas are:

(a) the support of automatic test and

checkout eauipment [13,16];

(b) the support of eauipment at remote

locations; and

(c) in the face of decreased defense

spending, to optimize the entire calibration and maintenance structure [13,15].

Problems in each of these areas have two aspects. The first is the need for dynamic

standards and methods for their use to support or verify measurements made under time

31
constraint with automatic test equipment, es- pecially that under computer control. Such

standards simply do not exist and their ab- sence both prevents direct verification of

the quality of individual measurements made

by present equipment and limits the advance

of automatic testing by confining its application to the measurement of those parameters for which static standards exist. For example, the so-called third generation ATE system makes measurements using sampling

techniques and arrives at final results

through harmonic or Fourier analysis software. System capabilities are given, how- ever, only in terms of derated rms or average voltage measurement specifications as lack of knowledge of the information content

of a single sample and a lack of arbitrary

wave form standards precludes the precise

calibration of such a system. (Specifications are derated relative to the potential

accuracy of the sampling device.)

The second aspect has to do with the

achievement of adequate measurement accuracy

at acceptable cost. Accuracy requirements

for the support of end items in the military

inventory are gradually becoming more stringent as electronic components and systems

increase in quality and sophistication and

improved reliability is sought for strategic

or economic reasons. At the same time budget decreases result in reduced resources

for measurement support and quality activities. Support equipment for new systems

and test equipment used in development and

repair activities include new instruments

with performance characteristics rivaling

the best measurement capabilities of the

typical DoD calibration laboratory.

These factors result in the need for the

development of new calibration procedures,

better training of technicians and, in some instances, exhancement of calibration and

measurement accuracies through new standards

or more sophisticated measurement experiments. Automated systems for the calibration of general purpose test equipment, the

use of MAP techniques for the support of

line calibration laboratories, and in situ

tests of both ATE systems and electronics

in aircraft, field installations and sur- face vessels are all being employed to deal

with these problems.

Detailed technical problems within the

system are dealt with by the professional

staffs of the Air Force, Army, and Navy metrology engineering centers. Specific, longterm problems are dealt with by these people.

In those instances where the advancement of

measurement science or new standards are re- quired, the DoD enlists the help of NBS through the sponsorship of engineering projects. Typical objectives of such projects

are the development of an al 1 -cryogenic voltage standard accurate at the part in 1 n8 level; the design of a low-frequency, lowvoltage measurement instrument to enhance vibration measurement capabilities; and the

development of an automated capacitance

bridge with which DoD primary laboratories

can provide improved service at reduced cost.

In addition to providing this measurement

science support, the NBS serves as a basis of

measurement uniformity for the DoD system by

supportinq the four primary standards laboratories through calibration services and MAP

acti vi ti es

.

The instrumentation industry. This industry

was covered in Sec. 2.2.2.2.

Electric power industry (SIC 3825, 3511, 361,

362 , and ^9 1 . The electric power industry

has two components, the generation and distribution of power (SIC 491) and the manufacture of equipment for the generation and mon- itoring of electric power.

The generation, distribution, and sale of

electric energy is the largest single business in the U.S. Approximate sales in 1973 were $31.7 billion and in 1974 were $39. 1 billion. In 1975 the industry sold over 1.7

trillion kilowatthours to nearly 82 million

customers for an estimated revenue of $47.9

billion [18,19].

The production of turbines and turbine

generator sets produced shipments valued at $2.^ billion in 1975. Shipments for 1976 are expected to increase by about eight percent

to $2.5 billion. Seventy-three businesses

employ 47,000 workers in the production of

this equipment [18]. Production of transformers, switch gear, and industrial controls for

power distribution (SIC Codes 3612, 3613,

3622) totaled $6.7 billion in 1975 and is ex- pected to reach $7.1 billion in 1976. More

than 2on firms are engaged in the production

of transformers alone and employ over 50,000

people T'^JO]. Electrical measurements are required by this segment of the industry for

quality control purposes. The levels of ac- curacy to be found are generally lower than

those at the state-of-the-art and readily

achievable with off-the-shelf instrumentation, but they are required to enable quality of these goods. No major metrology

problems are evident here.

In addition to being one of the key industries in the U.S., the electric power industry supplies most of the rest of industry

with motive energy. This is done through a system of interlocking grids of independent

power companies. Electrical measurements

are necessary for the monitoring and control of the power flow in the grid as well

32
as for energy metering by both power companies and their customers. Measurement problems include:

(a) the determination of transformer

ratios at high voltages;

(b) the characterization of high voltage

capaci tors

(c) the measurement of the dissipation

factor of high voltage capacitors;

(d) the accurate calibration of watthour

meters

(e) the development of techniques for

measurements in support of research to improve the transmission and distribution of

electric power;

(f) the measurement of transient signals

at high voltages; and

(g) the development of time-of-day metering techniques to enable the use of a rate

scale in which the price of electricity in- creases during periods of peak demand.

NBS is involved in each of the above

areas. The High Voltage Measurements Section is engaged in research and development

programs generally supported by the Electric

Power Research Institute and the Department

of Energy designed to achieve the measurement capabilities at high voltages needed to support both basic research and power system

operations. Examples of such projects are those to provide capability for measurement

of pulses and transients of up to several

million volts, to develop systems for the 7'?' situ calibration of coupling capacitor voltage transformers at voltages up to megavolt

levels, and to improve the standards used

for the measurement of current and power at power line frequencies.

In addition, NBS calibration services

provide the basis for uniform measurement

of electrical parameters necessary to dayto-day power company operations. NBS calibrations of standard cells, resistors, and

watthour meters stand behind all measurements made for metering purposes, including

those using the watthour meters found on every home in the U.S. Companies rely on

NBS calibrations of high voltage capacitors,

transformers and shunt reactors to maintain

the efficiency of the power distribution system throughout the country. These services

could not be provided without a strong, on- going research effort in high voltage measurement technology such as exists in NBS

today

.

Research

.

In this category fall all independent research organizations, universities,

and national laboratories. Since much of

the research done in every field is experimental, the ability to make accurate electrical measurements is a necessity. An example

of how precise measurements are needed is seen in a program at the University of Penn- sylvania for the study of the electrical

properties of solid-state, cryogenic

Josephson junctions. The purpose of this

work was to determine an experimental value

for the quantity e/h with sufficient accuracy to enable its use in the verification of

quantum el ectrodynamic theory. To do this,

a measurement of its voltage output had to be made with the maximum available accuracy,

that is 0.1 ppm relative to the legal volt.

This necessitated the construction of a special instrumentation and the initiation of a special effort, both at NBS and the University of Pennsylvania, to verify the accuracy

of the University's voltage standards.

A second example is to be found at Argonne National Laboratory, where extremely

precise calorimetry work requires that voltage and resistance measurements be made with

accuracies in the part per million realm.

The experimenter is compelled to keep his own set of standards which are calibrated at

NBS

.

The energy crisis and the resulting perception that electricity will become the dominant means of energy utilization has fostered research, sponsored primarily by the De- partment of Energy (DOE) and the Electric

Power and Research Institute (EPRI), for the

increased generation and improved transmission of electric power. This research is being carried out in industry, at universities, and in various national laboratories,

such as Brookhaven and Oak Ridge. Typical

projects are the investigation of the use of < superconducting transmission lines, ultrahigh voltage overhead lines, direct current

transmission, solar energy, and cryogenic

motors and generators. Approximately $14.3

million has been invested in FY 76 for trans- mission and distribution research by DOE and

$2^.6 million by EPRI for calendar year

1976 ri9].

The success of such research hinges on the ability to make accurate measurements at high voltages and under difficult environmental conditions and in many cases adequate

techniaues and standards for such measurements do not exist. As mentioned in the previous section, NBS is undertaking a number of

research projects to establish the reauired

measurement methodology. Examples of projects specifically bearing on energy-related

research are those of applying the Kerr effect to map electric fields, the design and

construction of pulsed current and voltage

generators and associated measurement apparatus to enable calorimetric determinations

of thermal /physi cal properties of materials

used in nuclear reactors, and the development of calibration techniques in support

of instrumentation used to determine the

33
effects of fields associated with voltage

transmission lines on plant and animal life.

In other areas, NBS work in the fundamental constants field provides data contributing to the verification of physical theory,

such as quantum el ectrodynami c theory. NBS

has ongoing efforts in areas requiring precise electrical measurements. Determinations of the ampere, volt, Faraday, ohm, and

the gyromagnetic ratio of the proton are presently underway. NBS has participated in

the most recent (1973) least-squares adjustment of fundamental physical constants published by CODATA, the Committee on Data for

Science and Technology. Another such adjustment is to be carried out in 1980.

As has been shown, the National Electrical Measurement System pervades most of the

major industries and government agencies to

a larger extent. As might be expected, mea- surement problems and requirements stem from

two sources, the use of electronics as an implementor of manufacturing quality and

process control, computations, and communications and the electric power industry and its

needs for efficient power generation, distribution, and metering, ^Measurement technology

in the former instance covers the ranae from

dc to 1 megahertz at modest levels of voltage and power whereas in the second case mea- surements are generally of electrical parameters at dc and FO Hz and high power and

voltage levels.

Through its calibration and research ac- tivities, NBS provides the measurement system with its base, thereby ensuring needed

stability and accuracy in terms of SI units.

High-technology industries with the most

stringent accuracy requirements provide the

interface with NBS needed to enable virtually all electrical measurements made in the

U.S. to be expressed in terms of the national

units. Measurement accuracy in areas of more

than modest requirement is ensured by systems

in which the instruments used to make the

measurements are calibrated periodically us- • ing standards or test equipment with accuracy

capabilities from four to ten times better

in each case. A chain composed of such calibration links reaches from most commercial instrumentation back to standards supported by

NBS. The system remains viable due to mea- surement research performed at NBS and in the

instrumentation industry.

34
3. IMPACT, STATUS, AND TRENDS

OF THE MEASUREMENT SYSTEM

3.1.1 Functional, Technological, and

Scientific Applications

The use of electrical measurements generally falls into one of four categroies - the

production of reference data, setting and

testing to specifications, maintenance and

reliability activities, or the control of

manufacturing processes. Reference data, including physical and engineering data covered

in Section 2.2.3, is vital to designers of

virtually all high-technology products. The

Electrical Measurement System ensures that

such data have universal meaning by providing common reference bases in the electrical

units, both for those experimentalists who

produce the data and for those designers who

must use the characteristics of materials,

circuits, etc. in an engineering application.

The next major use of electrical measurements is in vendor determination of performance characteristics of manufactured products and customer testing of those same devices to ensure that their specifications or

the manufacturers claims are actually being

met. Most commercial electronics and electrical merchandise is traded in this fashion.

Electronic components, modules, instruments,

devices and systems are generally tested,

sometimes on a sampling basis, to specifications prior to their acceptance. The mea- surement system is the foundation for all aspects of this type of activity. The

availability of universal units of measure

permits i nterchangeabi 1 i ty of electronic

components and modules (a must for the mass production and subsequent maintenance of complex electronics) and multiple manufacturers

of commonly used circuit elements. These

factors, coupled with inexpensive production

techniques, enable all electronics products

to be produced inexpensively and to function

with a high degree of reliability.

Electrical measurements are vital to maintenance and reliability functions throughout

the electronics user community. Test equipment is used both to ensure the proper operation of functional electronic equipment, such

as radar sets, inertial guidance units, etc. used in critical applications (i.e., space

and weapons systems) on a periodic basis and

as a means of trouble-shooting and repairing

nonfunctional electrical and electronic equipment. This test equipment is generally

checked or calibrated periodically using more accurate standards and equipment through

the echelon system of standards and calibration laboratories which exists throughout industry and most government agencies involved

with technology.

The final major use of electrical measurements is for the control of industrial manu- facturing processes. Early automatic control of manufacturing processes was achieved

through pneumatics and electro-mechanical

servomechani sms . Besides being a prime source of power for the process itself, pneumatics gave the design engineer the ability

to implement various control algorithms tending to optimize the process. The advent of

electronic amplifiers enabled the implementation of these same functions electrically

with many control adjustments difficult or impossible to achieve pneumatically. Also over the years the development of transducers,

devices which produce electrical signals of

a known relationship to the magnitude of a particular physical quantity, has gradually

extended the versatility of electronic control. The advent of the inexpensive digital

computer along with electronic instrumentation with digital data outputs has hastened

the application of electronics in the control

field. Control systems based on digital com- puters have the advantages of speed of res- ponse, economy, and software signal conditioning. Not only does the latter make possible the use of exceedingly complex control

algorithims, but it also permits extreme

flexibility of modification without extensive hardware changes.

The most stringent measurement requirements come from the instrumentation industry,

the aerospace industry, and the Department

of Defense. The DoD and the NASA generate

stringent requirements for the accuracy and

reliability of guidance, weapons, and navigation systems. Accuracy requirements of

better then 0.0017: for various electrical

parameters exist in some of the new operational equipment itself. This level of re- quirement places a burden on the instrumentation industry which is called upon to provide the test equipment and support stan- dards necessary to the development, production, testing, and maintenance of the operational equipment. Further the test equipment

and standards themselves must he verified and

maintained in all three of these areas of

the economy. NBS plays a vital role in this

function by providing calibrations of stan- dards. Measurement Assurance Program ser- vices, reference data, and training services.

Less accurate — but in some cases no less

stringent — requirements come from the electric power and the semiconductor industries.

In addition to the routine measurements of

electric power for revenue purposes, the

power industry requires many difficult mea- surements under field conditions for both

operational and research purposes. Examples

of these are given in the previous section.

Large scale integration techniques have per35
mitted a great growth in complexity of circuit elements. Meanwhile, the ever-decreasing cost of these same products has lead to their use in many applications in which re- liability is critical, such as electronic

control of automobile brakes, medical life

support systems and instrumentation, and aircraft navigation systems. Testing of these

circuit elements must be done, therefore,

accurately and rapidly to achieve utility

and low cost. This simple factor has lead

to a surge of interest in automated testing

and requirements for support of electrical

measurements made "on the fly". There is a plethora of dynamic data conversion devices

on the market with which such measurements

may be made. Lacking are the standards

which form the means fay which a translation

may be made from traditional standards and

measurements, which involve no time constraints, to the new requirements for dynamic measurements.

On the other end of the measurement spectrum lie those electrical measurements which

are part of the day-to-day experience of the

typical man on the street. Examples are those made in the course of tuning an automobile; for repairing television, radio, or high-fidelity audio equipment; to maintain

home consumption of electric power; and to provide for the safe navigation of commercial airlines. Instruments used in the for- mer two cases are generally only supported by

the measurement system upon their failure.

The accuracies required in support of most consumer services are readily obtainable

since they lie in the 1 to 5 percent range.

Electrical measurements are used to control the quality of any item manufactured

by an automatic process. The use of transducers, which convert other physical parameters into electrical parameters, coupled

with electrical instruments with digital outputs enable any physical or chemical production process to be run under computer control. Thermocouples, strain gages, tachometers, and fluid level meters are examples

of transducers. Table 11 lists some articles whose production is made possible by

electrical reasurements.

3.1.2 Economic Jrpacts - Costs ?inH Beppfits

The costs incurred by the economy annually

for electrical measurements are very low by

comparison with benefits received. A survey

of the manpower available in the calibration

laboratories listed in the NCSL Directory of

Standards Laboratories shows a total of P7R

engineers and 3208 technicians for all mea- surement areas [14]. A conservative estimate

was made that there are roughly 1000 measurement engineers and 5000 technicians in that

Table IT. Representative heavily

measurement-dependent products

Electronic

Components (resistors, capacitors, etc)

Computers

Digital watches

Electronic calculators

Frequency standards

Guidance systems

Navigation equipment

Stereo receivers

Other

Engine blocks

Oil , gasol ine

Plastics

Ravon, nylon fabric

Steel

Synthetic rubber

portion nf the measurement s.^'Stem i/'hich nrovides standards and calibration support to the remainder of the system. Approximate

labor and overhead costs for that number of

people are estimated to total no more than

$130 million per year. The remainder of the

system is many hundred times larger and difficult to quantify. The degree of capital

i ntensi veness of the measurement system is illustrated by the annual expenditure of over $5.6 billion for new measurement instrumentation, of which $1.3 billion is test equipment Fgi.

The above manpower figures are totally

exclusive of test engineers and technicians

whose functions are not primarily concerned

with calibration measurements. Virtually

every electronics engineer (except digital

logic designers) must rely on electrical

measurements as a tool necessary to the

performance of his function.

Over the past ten years, in excess of

$9^ billion worth of electronic systems and

communications equipment were sold in the

U.S. no, 20]. All of this eouipment re- quires maintenance support, and much re- quires periodic calibration to insure its

proper operation. During the same period

over $11 billion worth of electronic test equipment was sold for that purpose [9,10];

All of this apparatus requires periodic

calibration. The scientific apparatus inventory is estimated at $12 billion for that same 10-year period [9].

The electronics market as a whole is supported by this measurement capability. Rross

sales for the industry were forecast at $64.9

billion in 1977 [21]. New automated systems

developed explicitly for testing integrated

3C
circuits, v/hich are becoming more and more

complex, enabled achievement of this sales

figure. This represents about a

9"' growth,

despite materials shortages and a general

economic decline.

3.1.3 Social and Human Impacts

The largest social impacts of the electrical measurements system lie in the medical

field and the public safety areas. Modern

instrumentation has made possible great

strides in diagnostic medicine. The bodies

of patients in intensive care units are monitored on a twenty-four hour basis by com- puter-controlled instrumentation systems.

These systems not only alert medical staff

members to impending crises, but provide a powerful tool in the analysis of the patient's condition. There are under development automated systems which would give physical examinations to individuals without

requiring a doctor in attendance. Electronic

measurement eauipment and computers form the

basis for new systems to perform internal

scans via ultrasonics or x-rays.

In the safety area, measurements are vital to ensure the reliability of electronic

equipment such as braking and Ignition systems for automobiles and navigation and landing systems for aircraft. The failure of any

of these systems could be calamitous, whether

due to component failure or electrical interference. Reliable measurements are necessary

to avoid failures from either cause.

3.2 Status and Trends of the System

The electronics sec::!-. At the present

time the National Electrical Measurement System is capable of handling nearly all of the

traditional measurement needs of our economy.

The accuracies available within the system

for so-called static electrical measurements,

i.e., those in which the measurement is not constrained to take place within a particular

time interval, far exceed any technical accuracy requirements. The common practice of

insisting upon accuracy ratios in calibrations of betv-'een three- and ten-to-one, a practice fostered by the Department of De- fense and NASA, generally ensures that specified accuracies are delivered within the

calibration traceability chain. However, the

system does have a serious fault which is not entirely technical in nature and which is being increasingly recognized and dealt with.

This fault is the lack of redundancy or feedback in the rigidly stylized, hierarchical

calibration/traceability structure to ensure

that the applied measurements supported by

the system are in fact appropriate and adequate and their quality has not been adversely affected by such factors as environment,

electromagnetic interference, or poor power

lines. Commercial and government organizations are slowly recognizing the need for

periodic sampling of measurements being made

on the production line, in the aircraft, or

at the power substation.

There are several areas in which traditional measurements needs are, at present,

unfulfilled. The most urgent of these are:

(a) characterization and specification

of power line properties. There have been

failures and erroneous data from instrumentation caused by spikes or hash in the power

line. The medical profession and medical

instrumentation industry are most severely

affected by this problem due to the seriousness of potential consequences. A committee

dealing with the problem has been formed un- der the auspices of the National Committee

for Clinical Laboratory Standards. The es- tablishment of specifications and measurement

techniques for interfering signals on power

lines will enable the design of better instruments and provide a basis for settling

the issue of legal liability for consequences of error. This issue arises from

the fact that instrument makers do not specify the limitations of their equipment in that regard and hospitals are not legally

bound to ensure a specified purity of content of the power mains.

(b) measurement of ac voltages at low

amplitudes (<5n mV) and frequencies (<50 Hz).

This measurement capability would be used

with transducers to make measurements of low

frequency vibrations such as those characteristic of trucks and helicopters. The De- partment of Defense and the transportation

industry require the ability to test the sus- ceptibility of various items of critical na- ture to damage by truck or air transportation.

(c) impedance measurements in the upper

ends of the low radio frequency range (20

kHz to 1 MHz). These impedances measurements are needed to support an increase in

carrier frequencies in some communications

systems. Increases in carrier frequency

will result in nroportional increases in

message capability.

(d) studies relating to reliability and

the predicition of long-term performance of

components and assemblies based on shortterm, high-precision data needed by the electronics industry for general improvements

in their product line.

(e) measurements of phase angle in the

frequency range from 1 Hz to 30 kHz. Phase

angle measurements are important to the testing of components, solid state circuits, and test equipment used in and to support com- munications and weapons systems. In the lat37
ter, some of the more precise measurements

are required for testing synchro's and re- solvers used to position the antenna of

search and target acquisition radar.

There are two other perceived problems

which affect the system. Technical information is disseminated primarily by word-ofmouth (between colleagues), through sales

efforts of instrument companies, and by technical publications in such journals as IEEE Transactions on Instrumentation and Measurement , Instrumentation Technology , f'etrol ogia , and Measurements and Data . Articles in the

above tend to be academic in nature. De- spite the existence of the Povernment Industry Data Exchange Program, which has a library of calibration procedures, and the

above-mentioned means of communication, useful technical information on a how-to-do-lt

level does not reach the bench-level metrologists and those outside the precise measurements field (i.e., quality control or automatic test equipment engineers). In many instances there is conflict instead of cooperation fostered by ignorance and no means of

communication. NBS is planning a series of

publications and seminars to help meet this

need.

The second is in the area of manpower.

Many of the highly-skilled technicians and

engineers in the field are on the verge of

retirement. New people in the field tend

to remain there only temporarily. Metrology

may in the future be caught in a three-way

trap between the lack of communications and

informal education opportunities, the decline of the armed forces as a source of ex- perienced people, and the Increasing sophistication of new instrumentation, which

requires a higher level of education and appreciation for its proper support.

Two major factors presently affect the

system and will apparently do so for the

foreseeable future. These are the revolution taking place In the electronics Industry, and the energy crisis. Advances In semiconductor fabrication technology and the

application of new semiconductor structures

to circuit design are resulting in the availability of very complex digital and analog

circuits in small, component-sized packages.

As a result an increasing number of standard

circuits, such as amplifiers, computer processing units, power supplies, digital multipliers, analog-to-digital converters, etc., are as available to the designer as resistors, transistors, and tubes have been in

the past. Because of this ready availability, electronic equipment has Increased —

and will continue to Increase - in functional

complexity and sophistication, while Its cost has dropped.

The solid state revolution has fostered

a parallel phenomenon in the computer field.

Minicomputers, which have only readily been

available for about the past 10 years, have

so improved that new models offer sophistication which could be found only on large

systems costing hundreds of thousands of

dollars not long ago. Yet a system with a fair-sized memory, reasonable software, and

a mass-storage peripheral can be purchased

for well under $15,000 at the present time.

And, now available are microprocessors, central processing units on a chip, with fairly

comprehensive capabilities. These devices

are inexpensive enough to permit their inclusion in electronic equipment to replace the

hand-wired logic circuitry normally used

there for controlling operations and trans- mitting data.

The above considerations have had and

will continue to have a major Impact on both

measurement requirements and the tools or means by which measurements can be made.

The increasing complexity of components,

sub-assemblies, equipment items, and electronics systems have resulted In increasingly

complex tests necessary to ensure quality in

the manufacture of such equipment, proper

performance while in use, and affordable

maintenance for it in the event of malfunction. Typically, tests may be comprised of

hundreds or thousands of measurements.

The only way that such tests can be performed In a reasonable time and with cost puter to control the measurements, acquire

and process the data, and analyse the re- sults. Cost effectiveness Is Increased by

running the system at a higher rate of speed.

Therefore, the thrusts of the instrumentation Industry are in the direction of In- creased accuracy of measurement at increasing speeds, and of making the instruments

as compatible as possible with computers.

The Impact of this industry on the measurement system is heightened by the fact that

the designers of automatic test equipment

(ATE) systems for both military and commercial applications design these systems using

the specifications for off-the-shelf test Instruments as building blocks in the design.

This leads to performance problems if the

instruments used do not perform as expected

because of environmental noise, or ground

problems. It may also lead to calibration

support problems requiring high-grade portable standards.

The future will bring even more complexity. The Department of Defense now requires

testability. Many new prime systems will

have the functional capability to test themselves. Most circuits will be designed with

testability in mind, that is, with special

input and output lines with the sole function of expediting testing. Some digital

38
devices will actually contain t;-;o similar

circuits with auxiliary circuits to compare

their behavior. Much is being done to lay

the foundation for the development of system testers, portable devices which can exercise a test system under use conditions

by simulating a typical units under test

[13,15,16].

The industrial and commercial sector tends

to have less stringent accuracy requirements

for electrical measurements than the military/aerospace sector. This results from the

lower technology level found in general industry. On the other hand, measurements are required to be made under severe ambient conditions. Because of this factor and the need

for a means of coping with a general decline

in productivity, the use of automatic test

and control systems will increase rapidly in

this sector over the foreseeable future.

Much effort is being expended in development

of computer-aided manufacturing (CAM) technology, the use of robots, and application

of computer-aided design (CAD) techniques in

various areas of industry, as well as in the use of automatic test equipment and transducers for quality assurance. Automatic test equipment as used in the

commercial sector differs in another way

from that developed for the military/aerospace complex. Military and space operations

have a critical nature due to the high potential for loss of life, property, and national

existence. This fact and the often unique

nature of the equipment employed in those

programs leads to the procurement of specially-designed or "custom" measurement instruments and automatic test systems suited for

testing of a specific prime system. In the

commercial sector cost considerations tend to force the use of off-the-shelf commercial instrumentation for automatic testing purposes.

This practice is expected to be positively affected by the recent adoption of standards

(IEEE 488 and American National Standards

Institute CAMAC standards) whose conventions

for interfacing instruments and other devices to computers are beginning to be adopted in the instrumentation industry.

The improvements of semiconductor technology have had a significant impact on the

instrumentation industry in a variety of

ways as shown above. Perhaps the greatest

impact is the growing use of microprocessors

within instruments. Not only are these

small computers used to perform calculations

on raw data to enable the display of useful

information (such as temperature instead of

voltage for thermocouple applications), but

in a more basic function, that of controlling

the internal operation of the instrument.

Contemporary voltmeters and other electronic

measurement instruments function using dedicated logic circuits to control timing.

range changing, and the conversion of analog

signals to digital information. Changes in

the mode of operation can only be made by

circuit modification. Use of microprocessors will permit modification of the instrument's operation through software, resulting in more flexibility of design and lower

production costs. Most instrumentation com- panies are actively engaged in the application of microprocessors to their product

line. At this point in time, announcements

have been made of new voltmeters, counters,

oscilloscopes, and multi-channel scanning

systems, all based on microprocessors.

At the present time, artifact standards,

apparatus and standard measurement techniques to support dynamic measurements of

electrical quantities simply are non-existent. Details of state-of-the-art dynamic

measurement techniques are the proprietary

secrets of the manufacturers of instruments

and signal-conversion devices. As a result,

manufacturers and users of automatic test equipment and systems attempt to ensure the

quality of performance of such systems

through the manual calibration of system

components or the measurement of known static quantities by the system. Neither process gives valid assurance of adequacy of

performance. Such assurance is virtually

impossible without appropriate standards.

The lack of standards also affects the

development of new systems. The designer

may now use published equipment specifications (which in many cases are not uniform

in meaning) to achieve an approximation of

his design goal and then use measurement

results to "fine tune" the system because

standards are not available as design tools.

He may alternatively over-specify in speed

and accuracy to ensure good results. Un- needed accuracy and speed are costly and may

lull the designer to believe he has no analog measurement problems when in fact

one may be created by external considerations, such as the impedance characteristics

of the interface betv^een the system and the

unit under test. That the development and establishment

of standards for dynamic measurements of

electrical quantities are a necessity to ease future growth of technology was one of

the conclusions reached during a v/orkshop

held at NBS in September 1974. The workshop,

which had 24 participants, representative of

bpth manufacturers and users, was convened

to identify critical measurement needs and

discuss standards for modern electronic instrumentation. A whole host of standards

and measurement techniques whose need re- sults from the semiconductor and computer

revolutions were identified [13]. They are best summarized in the abstract of the workshop report, NBS Technical Note 865, given

39
in Appendix C of this report.

The need for a static measurement capability will not diminish in the future. This

is true as static standards must form the basis for uniformity and stability of perfor- mance with time for all dynamic instrumentation. The present electrical standards which

provide the basis for accuracy for static

measurements are of materials and combinations of materials inherently more stable

than are semiconductor devices.

In addition, automated equipment is not yet capable of trouble-shooting and repairing

electronics equipment. Although automatic

fault diagnosis for both digital and analog

circuitry is a rapidly expanding area, the

techniques and philosophy are as yet primitive. The construction of present day equipment is such that machine repair would be

prohibitively costly. General purpose maintenance instrumentation must be calibrated

and repaired itself.

Consumer electronics is another rapidly

growing field which will have an effect on

the measurement system. At present, the

main function of the measurement system in

the consumer's market is to enable the maintenance and repair of equipment. However,

the use of electronics for both safety and

energy conservation purposes is growing rapidly in the automobile industry. The potential for disaster due to failure of electronic ignition or braking systems will lead

to more measurements for reliability or quality control either voluntarily, as the

result of government regulation, or as the

economic consequence of successful litigation by crash victims or their survivors.

Another area of consumer electronics

which will increasingly impact the system

is that of medical instrumentation, both by

increasing the amount of support required

and by generating new measurement problems.

Not only is this use of instrumentation in

hospitals and medical research facilities

on the increase, but the summer of 1976 will

mark the beginning of regulation in this

field by the Food and Drug Administration.

Manufacturers of analytical instrumentation

are aware of their liabilities resulting

both from government action and from malpractice suits. A major problem at the present time is the electrical environment in

which instrumentation must function. A means of quantifying the "purity" of the

6n-Hz power line is needed, both to optimize

the design of instrument power supplies and

to enable hospitals to have proper electrical configurations.

The most important needs for the future

generated by the electronics portion of the

National Electrical Measurement System may

thus be summarized as:

(a) the need for standards for the dynamic measurement of electrical quantities

such as voltage, impedance, and power;

(b) the measurement methodology which

must be used with the above standards;

(c) the education of systems designers

in the necessity for and the use of the above,

before maintenance and failure costs escalate

to render system use impractical;

(d) the establishment of methods and ap- paratus to test computer-driven systems as systems, under conditions of actual use;

(e) the development of a theory to minimize the number of points requiring testing

in a complex system;

(f) a standard and measurement method by

which to assess the quality of ac power

available from the mains;

(g) the characterization of long-term

reliability and stability of electronic

components on the basis of short-term mea- surements (perhaps of parameters such as noise)

(h) standards for phase measurements and

for impedance measurements in the frequency

range from 20 kHz to 1 MHz;

(i) the development of improved switches

and relays;

( j ) better mechanisms for the communication of technical and management information throughout the system;

(k) a mechanism to ensure that regulatory and other government agency requirements 0 n the system are technically, economically, and logistically relaistic; and

(1) standardization in the computer soft- ware used for systems implementation of

measurements

.

The electric power industry. This subset

of the National Electrical Measurement Sys- tem requires a considerable measurement

capability, both to carry out its day-to-day

operations, and in support of research, the

urgency for which has been created by the

energy crisis. Support of operations re- quires a capability to perform measurements

of voltage, current, and impedance at voltages as high as 765,000 volts, a means of

measuring energy accurately at 60 Hz, mea- surements of transient (lightning impulse,

switching surges) voltages at levels in ex- cess of 2 MV, and the characterization of

diel ectrics.

Line-to-line voltages for bulk power

transmission in use or under consideration

by the industry are generally grouped in one of three categories. The high voltage

(HV) group extends from 69 kV (69,000 volts)

to 230 kV. Overhead lines are used for both

short and long distance movement of power

while underground cables are restricted to short distances. A considerable amount of

40
very long distance power transfer (e.g.,

between power companies) takes place on overhead lines at extra high voltages (EHV), some at 345 kV, but most at 500 kV. EHV lines at 765 kV are operational but under

somewhat limited use. One option for power

transfer in the future is by UHV (ultra-high

voltage) lines. Voltages ranging from 1.1 to 1.5 million volts are being considered.

For distribution of electric power, moderately high voltages between 200 and 45,000

volts are employed.

Measurements of voltage and current at these transmission and distribution voltage

levels are performed by means of voltage and

current transformers which reduce the magnitude of these parameters to a level where

they may be handled using conventional low

voltage meters. Both at HV and EHV levels,

inductively coupled transformers are used,

but at EHV there is a trend to use capacitive voltage transformers. Measurement

capability for the calibration of transformers for the HV range is generally adequate

throughout the industry. For the EHV range

the capability of calibrating current and

voltage transformers is generally limited

to the manufacturers of high voltage equipment. The capability of calibrating capacitive transformers (coupling capacitor

voltage transformers — CCVT's) in the place

of installation has recently been developed

at NBS with the support of the Electric

Power Research Institute. The use of high

voltage reactors and capacitors to reduce

circulating quadrature currents in transmission systems, and thus, reactive power,

leads to a need for the accurate measurement

of impedance and phase angle for this type

of device. This capability is generally

available only with the manufacturers.

Energy measurements are widely made by

the electric power industry for billing

purposes. This is a very well-established

area; it relates ultimately to the accuracy

of simple, residenti al -type watthour meters

and to more complicated industrial, commercial, and inter-utility metering systems.

There are over 80 million watthour meters

in the U.S., practically all of them rotating, induction-type devices. State utility

commissions legally require that such meters

do not exhibit a certain maximum error, usu- ally 2°'. The systems by which these meters

are calibrated are detailed in Sec. 4.2.1.

That this portion of the Measurement System

is under adequate control has been demonstrated by means of a round-robin experiment performed jointly by NBS and the

Edison Electric Institute [22].

Testing of the integrity of insulation

of equipment is an important part of the

quality control process of the electric

voltage equipment is subjected to very high

steady state and transient overvoltages

which must be measured with accuracies in

the 3 to 5°- range. Such accuracies are difficult to achieve as present instrumentation capable of handling the high voltages required has a poor pulse response

characteristic. A commonly used transient is the standard lightning impulse

(1.2 microsecond front, 50 microsecond tail)

which, for existing transmission voltages,

can be in excess of two million volts.

Another specialized test for the quality

of insulation is that for the level of partial (corona) discharges. The problems here are the complexity of instrumentation needed and the necessity to isolate the measured

phenomenon from interference. The basic ac- curacy is not a particular problem. Problems

do arise, nonetheless, due to the sophistication of the measurement operation and the

interpretation of data.

The following is a list of representative

measurement problems presently being identified in day-to-day power industry operations:

1. Stability of EHV capacitive transformers is unknown. Hence, their usefulness in

monitoring extra-high voltage is limited.

2. Means for calibrating impulse voltage

measuring systems are insufficient. Traceability is usually only through the manufacturer of the equipment. Periodic rechecking

is not widely practiced.

3. There is a lack of convenient and re- liable instrumentation to measure the power

of loads with very low power factors.

4. Measurement and test procedures to predict the life of insulation systems are

i nadequate.

5. Interpretation of data from corona and

partial discharge measurements requires additional research.

6. There are problems associated with the

very limited market of high voltage instruments. Often they are one of a kind; there

is little opportunity to obtain enough experience to optimize the design,

7. There is need for more in-service testing since many equipment types cannot be re- moved from use for test purposes. In- service measurement methods and instruments

are needed.

8. The industry could benefit from more

training of personnel in measurement and test techniques.

The above problems must be resolved by the

electric power sector in order to identify

components of optimum systems for the future.

The NBS role in solving these is to ensure

that the required measurement capability ex- ists and is available where these problems

are addressed.

41
The energy crisis, the rapid depletion of

petrochemical fuel reserves, and the future

promise of thermonuclear energy have spurred

a diversity of energy-related research efforts [19,23-26]. The effectiveness of many

of these efforts depends on the availability

of appropriate electrical measurement capabilities. In some areas, the key measurements are those generally associated with

the electronics community. For example, the

reliability of control and other auxilliary

electronic systems is recognized as a problem area. The operation and security of

future electric power networks are foreseen

to be more heavily computer-based, and contain large amounts of sophisticated instrumentation for monitoring and control of various parameters [26].

Work is going on in energy storage and

intermittent generation facilities to enable

the main power system generators to handle

only the base loads. Batteries are under

development for storage of energy generated

during off-peak hours for eventual peak-time

consumption. Measurements must be made to characterize the discharge of prototype batteries, as well as to determine their behavior under rapidly varying conditions of

use. Other areas dependent on electrical

measurement are those involving magnetohydrodynamics and fuel cells [26,27].

By observing the current developments in electric energy measuring devices and in

metering practices, one may expect early introduction of all-electronic metering systems. This meter may be a more sophisticated device combining the functions of watthour, demand, and power factor meters. It may be coupled to telemetry and computer

systems for automatic reading and time-ofthe-day metering. The accuracy requirements may be similar to those of conventional instruments, but the calibration procedures may be different.

Requirements for measurements at high

voltages come largely from R&D efforts to improve the capacity and efficiency of the

nation's system for the transmission of electric power from generating sites to areas of

use and the distribution of that power within

each area. In discussing these measurement

requirements, the development of future

electric power systems must be considered.

The principal driving forces appear to be:

(1) a continuing increase in the consumption

of electric power, requiring expanded transmission facilities; and (2) concern for us- able systems. The right-of-way available for

overhead transmission will be limited, re- quiring an increase in voltage to transmit

more power. However, there are some doubts

whether further increases will be permitted

because of potentially adverse environmental

effects. There will be pressures to put more transmission lines underground.

Some potential systems, for which re- search and development is underway or under

consideration, are outlined below [23-29]:

Transmission Systems

Overhead

UHV 60 Hz up to 1500 kV EHV and UHV dc up to 1200 kV Underground

Higher voltage tape cables

(765 kV ac)

Higher voltage extruded cables

(to 138 kV and 230 kV ac)

DC cables

SF5-insulated systems

Cryogenic systems

Substations (SFg-insulated)

Underground cables (improve reliability

and efficiency, reduce cost)

Transformers (improve efficiency)

Metering (time-of-day metering, remote

reading, all-electronic meters).

There will be requirements for many new types of measurement techniques at high

voltages occasioned by the above. A few of

these are the capability of making accurate

dielectric loss measurements under cryogenic

and other adverse conditions, the measurement

of transient voltages at UHV, the perfor- mance of needed calibrations (transformers,

reactors, capacitors) in an atmosphere of

SF5, and accurate measurements of electric

fields in non-uniform regions for environmental safety purposes. In addition, new calibration techniques will probably be needed

for such new types of measurement apparatus

as electronic wattmeters, capacitive voltage

transformers, and the electro-optical devices which may replace conventional current

transformers at EHV and UHV levels.

In conclusion, the power industry subset

of the NEMS generally functions well, although in several instances the industry

could benefit from improved measurements and

tests. The difficulty lies not so much in

the accuracy which can be achieved under

laboratory conditions and in the traceability

to basic standards, but in the very hostile

environment in which the measurements have

to be performed. Many tests are difficult

and expensive to stage because of high voltage considerations and the size of the equipment. Often, measurements are made to elucidate physical processes, e.g., those responsible for insulation aging and deterioration.

In such a case, the problem is frequently

associated with trying to relate the measurement results with the physical processes, a research problem on what to measure, not necessarily one of accuracy. Most of the

42
above problems are dealt with by the industry itself or appropriate agencies in the

Federal and state governments. NBS' res- ponsibility is for the development of mea- surement techniques and standards needed to solve these problems. NBS has neither the

mission or resources to tackle these problems directly itself.

Looking into the future, one sees great

activity in the development of new and improved electric transmission and distribution systems. There Is and will be a need

for new measurements to facilitate the development and to enable the operations of new

systems.

4. SURVEY OF NBS SERVICES

4.1 The Past

Calibration services for basic electrical

standards have gradually improved in accu- racy over the past twenty years. During

that period, the concept of measurement as- surance became the basis for new services as described later in this section. In the

high voltage measurements area some reduction in capability within the NBS facility

resulted from the loss of the Van Ness Street

facility. In 1967, work was begun on a new method of dissemination, utilizing the mea- surement transfer approach. Spurred on by

problems in the area of dc voltage measurements in standards and calibration laboratories, the effort culminated with the establishment in 1970 of the Volt Transfer Pro- gram as an alternative to standard cell calibrations at NBS. In this program, use is made of specially-tested transport standards

to monitor the ability of the client laboratory to make measurements of high accuracy

and precision, as well as to transfer the

unit. The Program has proven to be a powerful tool for the diagnosis of measurement

problems as well as a means for disseminating the volt at improved accuracies. Since

then similar programs in capacitance, resistance, energy, and voltage ratio have been

put into operation.

A new area of in situ high voltage mea- surements stemmed from the loss of fIBS inhouse measurement capability above 100 kV

and the development of portable bridges

based on the current comparator principle.

NBS equipment and personnel calibrate transformers, shunts, and capacitors at the actual site and under the conditions of use.

A similar approach is being taken for the

calibration of high current transformers.

Over the years, the Electricity Division

has contributed a wealth of new standards

and equipment to the measurement industry.

A partial list includes the Wenner bridge

and magnetometer, the' Rosa and Thomas-type

standard resistors, the Hermach thermal

transfer ac-dc voltage converter, the

Cutkosky ac thermometer bridge and the

Cutkosky fused silica dielectric capacitor.

All of these have been adopted for commercial manufacture, or provided significant

contribution to other products.

4.2 The Present - Scope of NBS Services

4.2.1 Description of NBS Services

Structure of the Electricity division. Th.e Electricity Division's goal is to provide

within the U.S. the central basis of a com43
plete and consistent system of electrical

measurements, standards, and related data

required by industry, commerce, government,

and the scientific community in their efforts

to advance science, technology, and equity

in trade for the public good. To achieve

this goal the Division has set the following

objecti ves

(a) to realize, with continuing improvement, the electrical units and to develop

improved means for their maintenance and

dissemination;

(b) to maintain and disseminate the electrical units and to test and calibrate electrical standards, instruments, and systems;

(c) to develop methods and instrumentation for the solution of problems requiring

electrical measurement;

(d) to determine essential data and constants requiring or related to electrical

measurements when not available with sufficient accuracy elsewhere;

(e) to serve actively in organizations

which set standards for electrical measurements and devices and to otherwise disseminate the Division's specialized knowledge;

and

(f) to evaluate the U.S. system of electrical measurements and to coordinate it

with the systems of other countries to achieve international compatibility.

The basic responsibilities of the

Absolute Eleatrical Measurements Section are

to relate the U.S. legal electrical units,

the ampere, farad, ohm, and volt, to the

absolute or SI (Systeme International)

units; to develop new and improved reference

standards for the SI units; to develop means

for maintaining surveillance of such referance standards; and to develop improved

means for disseminating the electrical units.

Until recent years, the legal electrical

units have been maintained by NBS using artifact (physical) standards, the stability of

which depended upon materials whose properties are generally affected by environmental

changes (temperature, physical shock, etc.)

and impurities, either physical or chemical.

For example, the value of a standard resistor, in addition to being sensitive to tem- perature changes, may undergo a long-term

drift as the result of changes in the intermolecular structure of the wire of which it

is made due to a physical shock and conse- quent deformation. This structure would in

time tend to slowly return to that of an annealed state and the wire resistivity

would reflect this slow change by its drift.

Although so-called absolute experiments,

which relate the electrical units to the

mechanical units, are performed from time

to time, they cannot because of their very

nature be performed often enough nor, for

most parameters, accurately enough to be of

use in ascertaining the drift rates of the

artifact standards in which are embodied

the legal units.

It is natural, therefore, that a significant portion of the Section's activity is

taken to exploit processes whose propeties

depend upon fundamental physical constants

for use as primary electrical standards. For example, the U.S. legal volt has been defined

since 1972 in terms of e/h, the ratio of the

electronic charge to Planck's constant. This

is done by the use of Josephson junctions,

weakly coupled junctions of superconductors

which act as precise, linear, frequency-tovoltage converters for which e/h is a con- version factor. Section work currently

includes the development of all cryogenic instruments based on the Josephson effect and

dc current transformer techniques to improve

the quality of the volt (reduce random error)

by an order of magnitude to one part in 10^

and the exploitation of the Josephson effect

for commercially-available laboratory voltage standards at the one part per million

level. Because of the nature of the process,

such a device would never need calibration.

Work in this area and on related voltage

measurements has led to a number of "spinoff" advancements in measurement technology.

Examples include the development of high ac- curacy, sub-millivolt potentiometric methods,

new techniques for the dissemination of the

volt (map's), application of sophisticated

statistical techniques to standard cell intercompari sons and other measurements, development of automation techniques, and the

design of the world's "cleanest" automated

switching systems.

Present activity in the area of absolute

measurements includes the determination of

the farad and ohm from the unit of length via

the calculable capacitor. This device is ca- pable of producing a change in capacitance

very precisely related to the displacement of

its guard electrodes. After a development

period of a decade, a preliminary measurement of the ohm has been made with an ac- curacy of 0.05 parts in a million [3], Perhaps equally significant are the developments which were required to achieve the ca- pabilities of maintaining the farad at the

commensurate level of stability and of making

the translation between the unit of capacitance at 5 picofarads, as measured using ac techniques, and the unit of dc resistance at one ohm. New capacitance standards based on the use of a deposited, fused silica dielectric were developed. Although they are inherently quite stable (less than 0.1 ppm per

year drift), their large temperature coef44
ficient required development of temperature

control and measurement techniques at the

microkelvin level of precision. These were

later successfully applied in the construction of a new type of standard cell enclosure. More sensitive amplification and

bridge techniques developed for the necessary

scaling from 0.5 to 1000 pF (10^ ohms at 1592 Hz) are now being employed in the development of automated equipment for impedance

intercomparisons.

Other measurement activities currently un- derway in the Absolute Electrical Measurements Section include measurements of the

proton gyromagnetic ratio, using the lowfield method; the measurement of the Faraday,

using the silver coulometer; the planning of new experiments of the ampere and y using

the high-field method; and the exploitation

of cryogenic techniques for the measurement

of resistance standards.

The equipment and facilities available

cover the range from cryogenic and microwave

apparatus to precision dc potentiometers and

ac bridges^. The NBS nonmagnetic facility,

under the jurisdiction of the Section, is available for research requiring a wellcharacterized and controllable magnetic en- vironment. A sputtering laboratory is presently being set up as a tool for cryogenic

and solid state thin film research.

The Absolute Electrical Measurements Section provides the technical base for all of

the measurement activities of the Division.

It disseminates the units of capacitance and

voltage to the Electrical Reference Standards

Section which, in turn, passes needed units

to the other two sections. The latter three

provide the majority of direct technical

services to the National Measurement System,

The Electrical Instrument.'? Section is

responsible for the development of standards

and measurement methodology to support modern, high-speed, electronic instrumentation.

Efforts are underway to provide for the determination of the accuracy of modular ana- log-to-digital and digital-to-analog converters under both static and dynamic conditions. The characterization of high-speed

sampling devices will also be investigated.

Time and speed-related properties which re- quire standards for measurement are risetime,

dynamic or instantaneous input impedance,

settling curve characterization, aperature

time (length and start point), etc. It is expected that the techniques discovered will

"spill over" into the lower speed, high ac- curacy instrumentation area. Previous work

done in the Section on measurements of rms

ac voltage using thermal converter techniques

is being applied to the development of improved ac voltage standards, needed for the

support of modern instrumentation.

Experience gained from earlier work on the development of a sampling wattmeter will

be used to solve two critical problems. The

sampling techniques and mathematical theory

with which to compute the phase angle difference between two alternating signals are

known. Their application to the actual mea- surement situation is being made. The feasibility of using sampling techniques for

the measurement of the power of irregular

waveforms is being studied as well.

The High Voltage Measurements Section

provides measurement support for the electric power industry and its suppliers and users, in addition to conducting research

and development in measurement techniques

and instrumentation for use at voltage and

power levels which exceed those normally

encountered in a standards laboratory.

Calibration services are provided for current, voltage, and energy measurements at power line frequencies and voltages, as well

as for high voltage devices, such as trans- formers, dc and ac voltage dividers, and

impulse dividers. Typically, the Section is concerned with measurements at voltages in

the range from several hundred volts to several hundred kilovolts; reactive power

levels are frequently of the order of

several hundred megavolt-amperes.

The scope of the Section activities is

illustrated by the following current re- search and calibration projects:

(a) alternating voltage measurements - voltage (potential) transformers and other

types of high voltage dividers; bridges and

comparators for calibrating voltage transformers and dividers;

(b) direct voltage measurements - resistive dividers; generating voltmeters; electrostatic voltmeters;

(c) measurement of transient voltages - electro-optic techniques (utilization of Kerr cell); resistive pulse dividers;

(d) impedance measurements at high voltage - high voltage standard capacitors;

standards for power factor correction ca- pacitors; high voltage capacitance bridges;

self-balancing bridges for measuring losses

in shunt reactors; and

(e) measurement of current in high voltage lines - optical telemetry techniques.

The Electrical Eeference Standards Section is primarily responsible for the dissemination of the basic U. S. legal electrical units (capacitance, inductance, resistance, and voltage). These units are disseminated through the calibration in NBS laboratories of standard resistors, capac45
itors, inductors, and voltage cells owned by

organizations from all segments of industry

and government. The units are extended

through the calibration of potentiometers,

bridges, volt ratio standards, inductive

voltage dividers, and other ratio devices.

The units of capacitance, resistance, and

voltage are disseminated additionally by means of cooperative (Measurement Assurance

Program (MAP) services for those laboratories

requiring the ultimate in accuracy or desiring to characterize their measurement pro- cesses. These programs employ the use of

extremely accurate transportable standards

and carefully designed experiments to determine the uncertainty with which the client

continues the dissemination process.

The Section also engages in applied re- search work to advance the state-of-the-art

of both the maintenance and dissemination

processes. One example of such work is the

development of the (Measurement Assurance

Program for capacitance. The measurement

assurance concept leads to determination of

an all-embracing uncertainty statement, the

product of characterizing the capability of

a client's laboratory to make a specific

measurement. This is done by regarding the

total calibration, maintenance, and dissemination process to any point as a system and

statistically sampling the output of that

system on a basis dictated by the measurement needs of the system. Through the use of NBS transport standards, all random and

systematic errors are determined, including

effects of time, transportation, operators,

equipment, grounding, and ambient conditions.

After satisfactory performance has been documented, information from the system is used

as feedback to reassign the values of the

client's standards to agree with the legal

units. The pursuit of a MAP service for ca- pacitance entailed a study of the transport

and temperature characteristics of commercial capacitors at the 1000-pF level and, as

a result, the design, construction, and testing of a new transport standard.

The Division also serves the National

Measurement System through its committee

activities, consulting efforts, outside-sponsored research and development work, and by

publishing the results of its research and

development work, including that done to support NBS measurement services. Table 12 shows the various technical outputs of the

Division and the approximate level of effort

expended in each. It must be noted that,

because of overlap, the percentages add to more than one hundred.

External sources of program guidance direction are the Office of the Director, IBS; Office of Measurement Services, IBS; the

U.S. Army; the U.S. Navy; the Department of

Defense Calibration Coordination Group (CCG);

Department of Energy (DOE); the Electric

Power Research Institute; the National Conference of Standards Laboratories; the

NAS/NAE/NRC Evaluation Panel; and colleagues

in industry. Since we work in close cooperation on a day-to-day basis with counterparts

in the primary laboratories of the three DOD services, we are kept keenly aware of measurement needs in those laboratories. The CCG

funds projects of joint interest to the

Division and the military calibration structure. Recently, relations have been formalized with the National Conference of

Standards Laboratories which represents the

largest part of the Division's constituency.

Thus, the Electricity Division realizes,

maintains, and disseminates the electrical

units and related quantities to the Electrical Measurement System. These parameters

are disseminated through the Measurement

Assurance Programs and through the calibration of electrical standards and instruments.

The quantities disseminated by the Division

are all derived from three basic maintained

units, those of resistance, capacitance, and

voltage, and the unitless electrical quantities of resistance ratio, impedance ratio,

and ac-dc current difference. The units and

related quantities disseminated and the means

of their dissemination are shown in table

13, page ^P. The technical infrastructure has two com- ponents. One is created as a result of the

measurement support requirements of the electronics field and the other is the result of

requirements of the electric power industry.

The requirements of the electronics industry

are of higher accuracy and over a more limited range of voltage and current than those

of the power industry. They cover a wider

frequency range, however, going up to 1 MHz

in some cases. Power companies are generally concerned only with dc, 60 Hz, and

pulse measurements, but at voltage and cur- rents as high as 2 million volts and 50,000

amperes, respectively.

Measurements for Electronics.

(a) DC Measurements.

Voltage measurements of signals ranging

from a few millivolts (thermocouple outputs)

to 100 volts (power supplies for cathode ray

and other tubes) are required by the electronics field. The basic unit of dc voltage

is disseminated by the Electricity Division

in two ways. The more accurate is the Volt

Transfer Program in which an NBS transport

standard is used to determine the difference

between the client's unit of voltage and the

legal unit. The uncertainty of this process

46
Table 12. Electricity Division technical outputs

Results and Reports from Sponsored Research and Development 20%

1. DoD CCG (71 .5k$)

2. DOE (262. 7k$)

3. Health, Education, and Welfare (FDA/BRH)

4. Navy (36k$)

5. Electric Power Research Institute (148k$

6. DoD (20k$)

7. DoD (Army (7.5k$)

(5k$)

- over several years)

Committee Activities 5%

1. lEC (International Electrotechnical Commission)

2. ANSI (American National Standards Institute)

3. IEEE (Institute of Electrical and Electronics Engineers]

4. OIML (International Organization for Legal Metrology)

5. Internal NBS activities

Consul ting

1. Army

2. Navy

3. Air Force

4. NBS

78%

5. Aerospace Industry

6. General Industry

7. Electronics Industry

8. Standards Producers

Calibratiofis and Testing (Estimated 377k$ FY76 Income) 78%

Industry

(80%)

Aerospace

El ectronics

Instrumentation

General

Power

Other NBS - Heat Division

Physical Chemistry Division

Office of Weights and Measures

Applied Radiation Division

Optical Physics Division

Electronic Technology Division

Government - Navy

(15%) Army

Air Force

NASA

Interior (Bureau of Re- clamation)

NOAA

FAA

FDA (HEW)

Bonneville Power Administration

Public Health Service (HEW) EPA TVA

Measurement Assurance Programs (Estimated 45k$ FY76 Income) 12%

1. NASA 4. 2. DOE 5, 3. Aerospace Industries 6.

Publication of NBS-Supported Research and Development

Power Industry

DoD Instrumentation Industry

40%

1. Metrologia

2. IEEE Transactions

3. IEEE Proceedings

47
Table 13. Dissemination services of the Electricity Division

Quantity Disseminated Means

DC Volt

Resistance

Capacitance

Inductance

Ratio

AC-DC Difference

Power

Energy

Volt Transfer Program

Standard Cell Calibrations

Solid State Voltage Reference Device

Cal ibrations

Resistance Transfer Service

Standard Resistor Calibrations

Shunt Calibrations

Capacitance Transfer Service

Standard Capacitor Calibrations

Calibration of Power Factor Capacitors

Standard Inductor Calibrations

Inductive Voltage Divider Calibrations

Current & Voltage Transformer Calibrations

HV Transformer Calibrations

Pulse Divider Calibrations

Volt Ratio MAP Volt Box Calibrations

Resistive Apparatus Calibrations

Resistive Voltage Divider (HV) Calibrations

Thermal Voltage & Current Converter

Cal ibrations

Wattmeter Calibrations

Watthour Meter Calibrations

is about 0.42 ppm. The other way is through

the calibration of saturated standard cells

submitted by the client to the Division for

test. The uncertainty of the test is 0.4

ppm, but transportation effects can raise

that to 1.0 ppm in any context of use. Resistance measurements are used for a large variety of purposes in the electronics

industry. The most stringent requirements

come from the instrumentation industry where

precision resistance components are used in

ratio applications such as ladders (resistive scaling networks) for analog-to-digital

converters and in operational amplifier circuits to provide accurate gain factors. The

unit of resistance is disseminated in two ways from the Division. The Resistance Pro- gram service in which, like the Volt Transfer Program, a set of transport standards is used to determine the difference between the

unit as disseminated by the client and the

legal unit. The Division also provides for

the calibration of standard resistors of decade values between 10"^ and 10'^ ohms. The

uncertainty associated with the Resistance

Transfer Service depends upon the nominal

value of resistors used and the capability

of the client. Transfers at the one- ohm

level have been made with a total uncertainty

of 0.2 ppm. The uncertainty of a regular

calibration is 0.08 ppm at that level, but

transportation effects and errors incurred

in the client's laboratory are not included.

Resistance ratio measurements are used

primarily as tools to scale or subdivide the

units of voltage and resistance. They are

used in the calibration of test equipment

such as digital voltmeter calibrators and

digital multimeters and in the calibration

of other resistive apparatus such as resistance bridges, potentiometers, volt boxes,

and ratio sets. The types of devices used for such mea- surements are potentiometers, volt boxes,

voltage dividers, universal ratio sets, and

Kel vin-Varley dividers. Of these, the last

two are the least specialized. They may be

used to calibrate any of the others. They

can also serve as instruments for two and

four-terminal resistance measurements and

voltage measurements.

Resistance ratios have the useful quality

that they can be established to very high

accuracies without the use of standards.

Consequently, measurements of ratio quantities are not legally required to be trace- able to national standards. However, the

Division calibrates ratio measuring devices

since the facilities for doing so, with very

high accuracies and with a minimum of diffi48
culty, are available. Calibration uncertainties for these devices are generally related

to the resolution of the device (except for

volt boxes) and range from 0.02 ppm to several hundred ppm. The Division also offers the Volt Ratio

Measurement Assurance Program. It is similar in concept to both the Volt Transfer

Program and the Resistance Transfer Service

except that, if measurement difficulties are encountered, a transportable measuring instrument can be sent to the client to be

used as a trouble-shooting device. The un- certainty, due to transportation and measurement, of such a transfer is 1.5 ppm and it

embraces uncertainties due to transportation

and measurement errors at the client's laboratory, as well as at NBS.

(b) AC Measurements.

The unit of capacitance is disseminated

mainly through the calibration of standard

capacitors with values of 10, 100 and 1000

pF at 50, 60, 400 and 1000 Hz. The uncer- tainties of these measurements are 0.5, 0.6

and 5.0 ppm, respectively. The large in- crease in uncertainty for the 1000-pF capacitor is due to the different construction of

the standards used at that level. A typical

standards laboratory should be able to use these standards to make measurements of ca- pacitance in that range of magnitude with no large increase in uncertainty. Such a laboratory would usually have a group of 1000-pF

capacitors as a standard and with normal

equipment should be able to make measurements with a total uncertainty of less than

ten parts per million. This has been borne

out experimentally in tests with military

laboratories.

Inductance measurements are primarily

used industrially for testing of component

chokes and for quality checking of magnetic

recording heads during production. Accuracies required and available in this area are

low. Bridges used to make inductance mea- surements on the production line are accurate to 1% at best, and the capability of

the Electricity Division to report the values of standard inductors with an accuracy

of 200 ppm is apparently adequate for cur- rent and known future needs.

AC voltage measurements are made primarily with digital voltmeters at the applications level. Accuracies of such meters can

be as high as 0.05% over a range of voltages

from 0 to 1000 volts. They are calibrated

using commercially available calibrators

which are accurate to about 0.02%. These

devices are calibrated by using an ac-dc

thermal voltage converter to permit comparison between their outputs and those of very

wel 1 -cal i brated dc sources, known as calibrators. The dc calibrators are then verified using standard cells and resistive

ratio devices. The ac-dc thermal voltage

converter is the critical element in this

chain since it permits the determination of

rms values of ac voltage using dc voltage

standards. These devices are calibrated by

the Electricity Division with ranging be- tween 5 and 200 ppm accuracies.

AC impedance ratio measurements are primarily used as calibration tools. The most

commonly used device in the electronics field

is the inductive voltage divider. This device is used to subdivide input voltages with

amplitudes as great as 100 volts with a mini- mum adjustment of 10"'^ of the input voltage.

Such devices are calibrated by the Division

with accuracies of 0.5 ppm of input voltage

(in phase) and 5 ppm of input voltage (quadrature).

Measurements for the Fewer Indrustr-^ . The

power industry used electrical measurements

in the control and monitoring of power. The

main quantities measured are energy, voltage,

voltage and current ratio, and capacitance.

Energy measurements are used to meter en- ergy distributed within the power system for

billing purposes. As stated previously, the

power companies are required by the various

state regulatory power commissions to supply

users with watthour meters accurate to 2'r with a 98% probability. Meter accuracies

are checked by sampling. Higher accuracy in

such measurements can result in smaller sam- ple sizes, leading to considerable savings.

Typically, power companies prefer to make

such measurements to 0.5% to minimize the

probability of fiscal loss by carrying out

tests at higher levels of confidence. A sam- pling of several utility companies revealed

that new meters were well within ±0.5%; old

meters, retested in sampling operations, were within 1%. Meter manufacturers must

accordingly use strict measurement tolerances . There are two routes whereby a utility

can obtain electric energy standards from

NBS. The most direct one is via a client's

rotating watthour meter standard which is sent to NBS for calibration. A variation of

this route is the Measurement Assurance Pro- gram (MAP) whereby an NBS-owned meter is

shipped to the client, who calibrates it as

an unknown item in his test circuit. This

procedure is preferable since it permits

testing of the client's entire system.

The second, or the dc calibration route,

consists of the client obtaining from NBS

the standards of resistance, voltage, (both

dc) and frequency. In addition, the ac-dc

49
difference of the client's special wattmeter

is also determined by NBS. The standards of

resistance and voltage provide the client

with the standard for the dc power. Utilizing the ac-dc difference of his wattmeter,

he can produce a known ac power. This is integrated using standard time (obtained from

standard frequency signals) to produce the

ac energy. See figure 3. In the past, the dc standards were considered more stable and more easily transferable

than the rotating watthour meter. Establishing an ac energy standard in this manner re- quires more work on the client's part. Until recently, the rotating standard was con- sidered as too fragile a device for transport,

unless hand-carried. During the past four

years, NBS has successfully shipped rotating

standards within the Measurement Assurance

Program without adverse effects. It should

be added that while most of the largest utilities get their standards directly from NBS,

there are utility companies, particularly the

small ones which rely on the standards of

other utility companies.

High voltage measurements are used for the

monitoring of energy flow in high voltage

lines. This is done by using transformers

to reduce voltages and currents in transmission lines to a level at which they may be

measured by low voltage instrumentation such

as watthour meters.

The accuracy requirements for transformers

in metering service are specified in American

National Standards Institute publications.

The Standard C12-1975, Code for Electricity

Metering, states that corrections for transformer errors do not have to be applied if

the transformers are of the 0.3% accuracy

class (correction less than 0.3%). Another

standard, C57. 13-1968, Requirements for In- strument Transformers, requires that the

equipment for calibration of metering transformers be accurate to 0.1%. No standards

exist for the higher echelon devices - the

reference transformers. The NBS-reported

accuracy of 0.03% for transformers above 100

kV has not resulted in any complaints; nevertheless, a desirability for 0.01% or even 0.002% accuracy has been mentioned by various individuals in the industry.

High voltage impedance measurements are used to measure the capacitance and loss an- gle of power factor correction capacitors,

and the impedance and phase angle of shunt

reactors. These devices are used to reduce

the reactive power in a transmission system.

Failure to do so would result in power circulating uselessly through the system. Such

devices are calibrated by the manufacturer

using as a standard a gas dielectric capacitor. The manufacturer's measurement system

may be checked out by an on-site calibration

of his standard and bridge using an NBS bridge

and standard. Calibrations of capacitors

rated up to 1000 yF and 100 kVA ratings can

be done at NBS. Appendix B contains a list of primary and

working standards used at NBS in support of

the measurement system.

4.2.2 Users of NBS Services

The users of the services made available

by the Electricity Division fall into the same general categories as do the major com- ponents serviced by the Measurement System.

The major categories are given below.

Table 14. Users of NBS services

Instrumentation Industry

Department of Defense

Aerospace Industries

Communications Systems Manufacturers

Electric Power Industry

Electrical Component Manufacturers

General Manufacturing Industries

Independent Calibration and

Testing Laboratories

Civilian Government Agencies

Uni versi ti es

User categories are listed roughly in

order of their dependence upon the services

offered. As has been stated previously, the

services provide the basis for accuracy of

all measurements which are in turn used to assure the quality, volume, and advancing

technology of produced goods.

4.2.3 Alternate Sources

There are no alternate sources for the

most important service that the Electricity

Division renders the Electrical Measurement

System. The Division provides the research

and development effort necessary to enable

the system to fulfill its needs in a timely

fashion. Other organizations are wellequipped, have competent staffs, and are able to supply calibrations of standards at accuracies approaching those available at

NBS for certain parameters. But none are motivated to make the magnitude of investment required for, nor have the responsibility for providing for, the research and

development in basic metrology needed to support the entire system. No one organization matches the breadth of the NBS capability and none match its capacity for fu- ture improvements or for responding to changing needs. For the measurement system

50
to function in an optimum way, services and

research must go hand in hand.

Commerce and industry today, even more

than at the turn of the century, require

traceability of measurements to a single

source as a necessity for accuracy, without

which interchangeabi lity of parts, ready re- pair, compatibility of electronic devices,

and ease of design would all be impossible.

In addition, because of its role as the premier source of standards for electro-technology and the fact that it is funded publicly

and represents no special interest, the Electricity Division is able to act as a neutral

third party - an arbiter in areas of technical dispute involving measurements.

Scenarios have been proposed to consider

what would be the results of turning the

bulk of the metrology dissemination and calibration work over to state or private calibration laboratories. To do so would result

in isolation of the Electricity Division from

the bulk of its user community and hence render it less, rather than more, responsive to

the needs of the system. The difficulty of

moving technology out to the system would

increase due to this isolation.

4.2.4 Funding Sources for NBS Services

The development of new services and the

improvement of existing calibration services

are supported by congressional ly-appropri ated

funds (NBS budget), augmented by funding from

private and government agencies outside NBS

on a contractural basis. Typically, the Division has about 20:-- of its budget provided

in this manner. Most of this comes from the

Department of Defense, to augment v/ork in

support of its measurement systems; and from

EPRI, the Electric Power Research Institute,

and the Department of Energy, for energy-related work. In addition, federal law requires the complete recovery of the costs of

providing calibration, measurement transfer,

and other routine services from the users of

such services. Revenue from this source con- stitutes approximately 14'- of the Division's

budget.

4.2.5 Mechanisms for Supplying Services

Dissemination services take place through

three mechanisms: the calibration of client

standards at NBS; Measurement Assurance Pro- gram services, which involve the use of NBS

transport standards to sample the measurement process output at a given place; and in

s'.tr^. calibrations of such devices as high

voltage transformers and capacitors by NBS

personnel using NBS apparatus and standards.

Dissemination of metrology information is

provided for by sponsorship of Division seminars and workshops, publications in the

scientific literature, participation in standards committee activities by staff members,

publication of tutorial articles such as Technical Notes, and by individual personal

interaction with members of the metrology

fraternity at large.

4.3 Impact of NBS Services

4.3.1 Economic Impact of Major User Classes

Although no accurate quantitative assessment of leverage is possible, an appreciation

of the potential impact of NBS services may

be gained by a consideration of the gross annual sales figures of those segments of industry it supports as shown in table 15. The Defense Department, of course, is vital to the well-being of our nation. It depends on measurements to ensure weapons

system reliability, and indirectly through

the aerospace and electronics industries,

Table 15, Electricity Di vision user classes

Number of Value of Shipments Number of

SIC Code People (bil 1 ions of S) Comipanies

CY 75

Electronic Systems 3662 330,000 9.6 86

Components 367 412,000 10.6 1420

Computers 3573 175,000 9.7 610

Engineering & Scientific

Instrumentation 3811 43,000 1.4 721 Measuring & Control

Instrumentation 3821 72,000 2.1 817 Test Equipment 3825 70,000 2.2 622

Power Equipment 351 44,000 2.4 74

Transformers 34433 18,000 .9 40

Electric Power 491 317,000 47.9 225

Aerospace 372,376 615,000 26.2 1225

51
superiority through technical sophistication.

All of these industries, with the exception

of the electric power industry, produce high

technology products and contritDute heavily

to our high standard of living. The power

industry applies research and uses high technology to provide us with the means to utilize energy conveniently and is responsible

in large measure for the industrial base of

the country.

4.3.2 Technological Impact of Services

Calibration and MAP services of the Electricity Division provide both the electronic

and electrical power industry segments of

the measurement system with the stable, basic electrical units upon which the accuracy

of measurements throughout the system depends. This support is vital to the development of new, sophisticated instrumentation

and to the maintenance and continuing effective use of the very large existing national

inventory of test equipment and measurement

instrumentation. This inventory of electrical measurement apparatus is the only

viable means of providing quality control

for manufacturing processes throughout industry, ensuring operational readiness of our sophisticated weapons systems, enabling

the high degree of reliability of electronics

and equipment vital to our manned space operations, making possible the reliable and

smooth functioning of the nation's communications and transportation networks, and

providing for the efficient and effective

distribution of electric power to industrial

and domestic consumers throughout the country. The importance of instrumentation and

the measurements it makes is borne out by two factors. The expected increase in test and measuring equipment for electrical quantities alone is 11% between 1975 and 1976

and that growth rate is expected to continue

through 1985, by which time $6.5 billion in

instruments will be produced annually [11].

This growth rate, especially in times of

economic hardship, is an indication of the

need for measurements. Secondly, to this

mu:>t be coupled the fact that the measurement capability per unit cost of instrumentation is rising dramatically due to the

semiconductor revolution and the inclusion

of microprocessors in individual instruments

[30]. Standards maintained by the Electricity Division and used to disseminate the

electrical units allow measurements made by

this instrumentation to be consistent

throughout the country and stable over time.

NBS services, such as consultative and

committee activities and publication of me- trology research and development work, are aimed at promulgating measurement technology

so that measurements may be made more efficiently, effectively, and accurately throughout the system. NBS representation is most

widespread on those technical committees of

the Institute of Electrical and Electronics

Engineers, the American National Standards

Institute, and the International Electrotechnical Commission which deal with electrical measurements. Literally hundreds of

inquiries per year about various electrical

measurements problems are handled by staff

members

.

Publications concerning measurement techniques have a heavy impact on the measurement community. Over 3000 copies of NBS

Technical Note 430, Designs for Survei 1 lance

of the Volt Maintained by a Small Group of

Saturated Standard Cells by Eicke and

Cameron have been distributed. The measurement techniques set forth in this document

were at the time of publication virtually

unknown in the electrical measurements field

outside of NBS and have since been adopted

by a significant number of metrology laboratories. This has resulted in general improvement in the quality of voltage measurements in standards laboratories as well as permitted the identification of potentially

serious measurement problems.

Some of the areas of technology and industry heavily supported in both development

and operational phases by the measurement

system are semiconductors, discrete electronic components, instrumentation (a user

as well as an implementor) ; communication;

navigation; chemistry; metals; and computers.

Electrical measuring instruments provide the

basic tools for physical, biomedical and

chemical research as well.

4.3.3 Pay-off from Changes in NBS Services

Two notable changes have occurred in re- cent years in services offered by the Electricity Division. The first is the increasing use of Measurement Assurance Program

services, starting with the Volt Transfer

Program, for the dissemination of the electrical units. In the case of all of these

services there have been two immediate technical effects: the units have been transferred with higher accuracy; and invalid

measurement techniques at users' locations

have been identified and their use curtailed

due to NBS analysis of data.

In a number of cases, there has been a third payoff. The techniques used in the

process have been successfully applied to the users' individual measurement systemo

The most definitive economic benefit has

been the extension of the interval between

calibrations for the clientele using these

services. This is made possible by the

52
improved accuracy of the transfer and the

methodology by which the data are reduced,

in comparison with usual methods used to ensure measurement traceabil ity. The

greatest measurable economic impact of this

type of service will most likely result from

the application of these specific techniques

to effect a reduction in cost of supplying

measurement support to production lines and

throughout quality control systems.

For a group of five California companies,

the availability of MAP services has meant a completely new method of establishing traceability. In the past, each company sent standards of voltage and resistance annually

to NBS for intercomparison. Now, each year

only one of the companies becomes involved

in an NBS voltage or resistance transfer.

During the same period of time, the group

undertakes a five-way intercomparison of the

appropriate units for each company, using

measurement transfer techniques. They have

reduced the cost of traceabil ity significantly in this fashion and each now has con- fidence in the standards of the others

should a failure occur in his own [31].

The second major change in the Division's

services occurred as a result of closing the

old NBS high voltage (HV) laboratory in

Washington, DC. In 1970, a decision was made and implemented to move the low and intermediate voltage support facilities and

offices of the High Voltage Measurements

Section to the Gaithersburg site. The HV laboratory was intended to be retained as a field station and used whenever the need arose for voltage levels above 50 kV. However, in 1971, the General Services

Administration, the owner of the laboratory

and site, asked NBS on short notice to va- cate the facilities in order to make the

land available for the Washington Technical

Institute. NBS abandoned the laboratory and

transferred the equipment for a nominal sum

to another government agency. Thus, NBS

gave up, and the Division lost, a facility

whose replacement cost today would range

from $5 to $10 million.

The basic reasons for this closing were

complex: low calibration workload, a lack of

funding of high voltage research by other

agencies; its vulnerable position as an isolated facility away from the main NBS campus; and NBS program priority decisions.

To retain some capability for calibrations and research in the high voltage measurements area, especially for measurements

required in revenue metering, a new mode of

operation was begun. Instead of doing all

HV work in-house at NBS, measurement services

above 100 kV are offered as on-site calibrations. Division staff members go either to customers' high voltage laboratories or to

one which belongs to an acceptable third

party. The NBS instruments and standards

used are designed with portability in mind.

For calibrations and research below 100 kV,

and intermediate voltage in-house facility

has been established at the NBS Gaithersburg

(MD) location.

This change in NBS facilities extensively

affected the electric power industry. While

retaining an acceptable calibration capability, it reduced the Division's capability

and flexibility to contribute to the research

requirements of electric power transmission

systems. The level of power industry support in the sixties, when the future of the

NBS high voltage laboratory was debated, may

not have indicated the need for it. However, the situation changed significantly in

the past few years.

The principal reason is the energy crunch

and the associated emphasis on energy-related R&D. Electric power R&D in industry has

been focused by the formation of the Electric Power Research Institute (EPRI), which

is the R&D arm of the power industry; and

the Department of Energy, which controls the

public funds related to energy research.

The combined transmission and distribution (T&D) budget for these organizations is about $40 million annually. The size of the

measurements component is difficult to assess exactly since it is diffused throughout

the entire program, but a safe estimate,

based on the problems of which NBS is aware, would be at least 1% of this or $400k an- nually.

In the past two years, power systems re- lated OA work in the Electricity Division

has increased from a negligible amount to about $250k annually. Further increases

still could be made if facilities and man- power were available.

In summary, the potential need for mea- surements R&D related to electric power systems is at least $400k annually. Even if

other constraints were removed, we could not undertake such a program fully without having access to our own or a closely located

HV laboratory. It also must be added that

T&D research (including measurements R&D)

relates to a projected capital investment of

$150 to $200 billion over the next 15 years.

53
4.4 Evaluation of NBS Program

The Electricity Division program is generally consistent with the needs of the electrical measurement system but inadequate in

several areas, such as the dynamic electrical standards area, due for the most part to limited resources, both of personnel and

funding. The most powerful tool for determining the needs of the measurement system

for the Division's services and output is the expertise of the technical staff of the

Division. By keeping current with trends

and advances in instrumentation and electronics, staff members identify potential

areas where NBS measurement support will be

needed as well as up-to-date tools to help

supply that support.

Other agency sponsors constitute a powerful means of identifying needs. In the electrical power area, responsibility for the

development of nearly all future technology

is in the hands of the Division's two major

sponsors, the Department of Energy (government) and the Electric Power Research Institute (private sector). Widespread Division

contacts within these two organizations en- sure early recognition of needs I'-ithin the

power industry.

State-of-the-art advancements in electronics, systems, and instrumentation generally

result from fulfillment of the new weapons

requirements of the Department of Defense.

The Division has a very close coupling with

the Defense Department through its Calibration Coordination Group. This DoD group,

which over the years has sponsored a large

amount of metrology development work in the

Division, apprises NBS staff members of fu- ture measurement requirements in the military system.

The National Conference of Standards Laboratories is a management-oriented organization comprised of companies and government

agencies with metrology interests. This

group is highly representative of the Electricity Division's clientele as there is

greater than a 80% overlap of NCSL member

companies and the Division's calibration ser- vices users. Recently, the Executive Board

of that organization approved a plan to con- stitute an NCSL liaison board to the Electricity Division. This board will serve both

to provide inputs for future planning in the

Division and as a vehicle for the dissemination of technical and management information

from NBS to NCSL member companies.

The National Academy of Sciences/Iiational

Academy of Engineering/National Research Council Evaluation Panel for the Electricity Division reviews the programs in the Division,

generally on an annual basis, and provides

valuable input for the determination of future program directions. The most recent

such panel had eight members representing

the viewpoints of the power industry, the

Federal energy research program, the Department of Defense, the academic community, the

electronics industry, the research community,

and the instrumentation industry. The Panel 's reports contain comments and recommendations on technical, managerial, and administrative matters as well as suggestions for

new directions. The annual meetings between

the Panel and staff members, although perhaps too brief, are very beneficial for the

exchange of technical information and views

too detailed to be of use in management re- ports . The most recent Panel was in full support

of the Division's ongoing programs, and es- pecially highlighted the need for work to be

done in the areas of measurements in support

of high voltage research and development and

high-speed dynamic standards for modern electronic instrumentation. The Panel identified

communications between the Division and its

constituency as being a major problem and

commented on the process of setting longterm development goals in the rapidly developing area of modern instrumentation.

As needs are identified, program priorities must be established. These priorities

are the result of careful consideration of

the degree to which response to the need

falls within the NBS mission, the magnitude

of the need, the resources (including expertise) available to deal with the problem,

and the likelihood of success in an appropriate time frame.

Major needs of the system for NBS services

include those for:

(a) basic standards to maintain stable na- tional electrical units;

(b) means of disseminating the units;

(c) "how-to-to-it" metrology information;

(d) dynamic measurement standards for modern instrumentation;

(e) techniques for the measurement of impedance, voltage, current, and dielectric

properties at high voltages; and

(f) the determination of fundamental physical constants, such as the Faraday and 2e/h.

The Electricity Division has on-going programs to respond to each of these areas of

need. Because of the widespread need of

these services and the need for an impartial,

technically competent organization to deliver

them, it is clear that they can be performed

only by a federal government agency. NBS is

the only agency with the expertise and stat- utory responsibility for providing them.

54
^.5 The Future

Activities in the Electricity Division

are at present undergoing a period of change.

Advantage has been taken of the completion

of a large number of projects in traditional

areas to effect reprogramming to bring effort

to bear on the solution of problems in new measurement areas. The Electricity Division's

capability to provide support for static mea- surements in the general instrumentation are generally more than adequate to meet present

needs. However, similar support is lacking

for the dynamic measurements (i.e., those

made under a time constraint) of electrical

quantities such as are made under computer

control. Hence a considerable effort is being devoted to a program to establish measurement methodology and standards in support of

modern, high-speed instrumentation. Investigations are proceeding to establish standards

and instrumentation to investigate high-speed

analog- to-digital and digital-to-analog con- version modules. A program to establish methodology for the proper support and implementation of electronic test equipment of high

accuracy is underway on a modest scale. The

Division is midway in the development of a system to provide an accurate measurement

base for the semiconductor industry at the

10-volt level

.

All of this activity is in response to the

needs perceived by Division personnel which

led to a workshop in September of 1974 to identify and quantify Critical Electrical Measurement Needs and Standards for Modern Electronic Instrumentation. The Workshop was attended by 24 engineers and scientists representing a variety of industrial viewpoints.

Automatic test equipment users, instrument

manufacturers, systems users and manufacturers, and the semiconductor module industry were represented, mostly at the engineering

manager, or vice-president level. The general conclusion of the Workshop supported the

Electricity Division's perception of needs

in this area. Other hitherto unidentified

needs were made known, most notably in the areas of pulse responses of components, dielectric hysteresis, and the characterization of ac line voltage with respect to transients, dynamic impedance, etc. [see Appendix

C].

In the area of dissemination of information, a program has been started to generate

a series of tutorial publications covering

various aspects of electrical metrology useful to the personnel of a typical standards

or calibration laboratory. An effort is being made to establish an Electricity Division newsletter in one technical journal and

to publish overview articles in other, more

generally based, periodicals, in order to

expose Division programs to the scientific

and engineering community and thus engender

feedback.

In discussing the measurements for electric power systems this report implicitly

and explicitly recognizes two areas: (1) the areas related to the "traditional" quantities

such as voltage, current, impedance and, es- pecially, power and energy; and (2) that area related to research and development of new apparatus and systems, primarily for transmission and distribution. In the latter area are also included those specialized and difficult measurements employed in the design

and quality control of present systems.

The delineation between the two areas is not very rigid and the term "traditional"

must be tempered since it does not imply lack

of need for research and development activity

As the instrumentation and transmission technologies change, NBS must meet the changing

measurement requirements for these basic

electrical quantities. As discussed elsewhere in this report, a very important item

in this first category is the measurement

of electric energy. Although currently this area is well in control, new instrumentation

and metering practices will be introduced

within the next five years which will place

additional requirements on the NBS services.

Electronic watthour meters are appearing in

interutility and large commercial and industrial metering installations. Load management based on variable rates for electric

energy is being considered. A more sophisticated instrument combining the functions

of a watthour meter and a demand meter has

been suggested. As with the conventional induction-type watthour meters, not only will

the accuracy and reliability be of concern,

but also the ease of remote reading and control and interfacing with a central computing

facility. Although its role is not entirely

clear at the moment, NBS will be required to provide rather different kinds of supportive

measurement services in the future in addition to the present routine calibrations and

t^AP services. New developments in this area

will be closely watched.

In measuring the traditional steady state

quantities, problems exist in calibrations

at higher voltages, where relatively few or- ganizations have a capability of calibrating

voltage transformers. Traceability to the

fundamental NBS-maintained standards is weak.

The Electricity Division will try to alleviate this situation by promoting field calibration services and through specific projects such as the development of the system

for calibration of coupling capacitor voltage transformers in substations.

With respect to the other area concerned

with R&D and specialized measurements, there

55
are numerous unresolved problems now and cer- tainly more will become evident as the R&D

in new transmission systems progresses. The

weakest area now is concerned with the mea- surement of high voltage transients, especially at extra high voltage (EHV) and ultrahigh voltage (UHV) levels. NBS will continue

to work in impulse measurements with particular emphasis on transferring our capabilities to the power industry. Contingent upon

the availability of resources, work should

be done on devices for measuring voltage,

current and power in high voltage dc transmission systems.

The Division will follow the developments

of new transmission systems and provide its

expertise for solving measurements -rel ated

problems. This area is proper for extra-NBS

support. An example is the development of

a superconducting ac transmission system.

High voltage measurements research related

to the insulation of superconducting cables

is already being performed. Superconducting

systems will have very high current capabilities. New methods will be needed to measure these currents.

Another new transmission system under

development uses SF5-insulated conductors.

Nonconventional measuring methods appear to offer cost and accuracy advantages in these

systems. This entire area is ripe for ex- ploration.

If overhead transmission enters the UHV region, electro-optical current transformers

will become very attractive. The NBS will

be in the best position to evaluate their ac- curacy capabilities by virtue of measurement

techniques in the UHV region developed here.

Potentially adverse effects on environment due to high electric fields, audible

noise and electromagnetic interference are

of great concern in connection with new EHV and UHV overhead systems. The Division will

offer measurement assistance to the agencies

primarily concerned with this problem.

Reprogrammi ng efforts to respond to all of these needs made evident a serious weakness in the Division. The Division simply

lacks the proper resources, people, and

funding to mount a comprehensive program in

each area without seriously eroding the supporting basic measurement program - there is concern that a proper job cannot be done

without ignoring clear responsibilities in

the traditional areas.

On the other hand, there would be a large

negative impact if the Division were to fail

to meet the needs being addressed by these

various activities. The state of the electronic marketplace is one of chaos with re- spect to high-speed electronics. Lack of common terminology and universally accepted

test procedures makes procurement by specification a difficult and hazardous procedure.

Since the definitions of temporal parameters

are nebulous, different interpretations are

used by different manufacturers and the buyer

has no means of evaluation except in terms of a specific application. The net result

is that much money is wasted on useless purchases and the over-specification of components to ensure adequate performance. The

presence of an authoritative, technically

competent, neutral "third party" such as NBS,

is urgently needed in the area to establish

commonal i ty

.

Why should NBS be involved in any of

this? The Federal government is the only or- ganization that can afford to look past to- morrow to the future in the area of measurement science and standards. Industrial con- cerns must have staying-in-business as a first consideration. That generally means a minimum of long-range (10-20 year) research

programs, and a great deal of motivation for

keeping potential profit-making results of

such research secret.

The National Bureau of Standards is the

only government organization with the base,

the expertise, and the legislative charter

to perform these functions. No other government laboratory has appropriate facilities or staff. Research in measurement methodology

would not be the primary concern where other

national needs such as national defense are

the responsibility of the organization. The

country needs one organization in which mea- surement activities and standards are the

primary concern as at NBS.

56
5. SUMMARY AND CONCLUSIONS

The National Measurement System for Electricity has two major components; those of

electronics and the electric power industry.

These are separately identified because of

the distinctly different nature of the n surements required in each. The former is comprised of the electronics and instrunentation industries and their users, while the

power subset of the system is comprised of

the electric utilities, manufacturers of

generating, transmitting and distributing

apparatus and, to some extent, the users of

electric energy.

The present measurement capability of the

electronics subset is more than adequate to support traditional measurements (those madf

manually or without time constraint) except

in a very few limited cases such as, low ' .— quency, low amplitude ac voltage measurements

and upper audio and lower radio frequency impedance measurements. However, due to the

impact of advances in semiconductor technology on the instrumentation, computer, and

electronics industries, and the resultant

increases in complexity of components, devices, and systems, a larger and larger percentage of measurements is being made by

electronic instrumentation under computer

control and under conditions in which time is

a constraining factor. This leap forward in

measurement technology has not been matched

by the development of appropriate standards

of measurements. Designers of automatic

test systems and equipment do not have the

benefits of either physical or written standards for dynamic electrical measurements as tools. Common terms, such as aperature and

settling time, used to describe dynamic p>^' erties of measurement equipment, do nc' universally accepted definitions. A _ physical standards, analogous to standard resistors, capacitors, and cells, for the quantification of dynamic properties do not exist.

Designers and users of modern test equipment

and instrumentation must use costly trial

and error or "overkill" methods for both the

development and maintenance of such equipment. Development of future, more accurate

and faster systems will be hampered by lack

of such standards.

In the electric power industry subset,

which deals basically with energy, voltage,

current, and impedance measurements at 60 Hz, some at very high voltage and impulse measurements at high voltages, the present ca- pabilities are generally adequate to support

today's operational requirements. However,

the electric power industry is beginning an

era of great change. The main forces for

change are the energy crisis and the appreciation of the small size of the remaining

supply of petroleum. Research efforts to improve the capacity and efficiency of elecpower generation, transmission, and distribution have been expanded greatly over the

past few years. New measurement methods

and standards are drastically needed to en- able this research to reach fruition and to support and maintain the new power systems

expected to result. Measurement methods

are needed for such things as calibration of

capacitive coupled voltage transformers

(CCVT's) for use at 500 kV and above; evaluating various types of prototype distributions systems, such as underground dc and gas insulated, cryogenic, or extruded insulation

systems, and overhead systems ranging as high

as 1.5 million volts; evaluation of environmental and interference effects of ultra-high

voltage overhead lines; and development of

tests to ensure that equipment on such lines

can withstand transient overvoltage and surge

currents caused by lightning and switching.

Energy metering, done largely at the present

time using rotating electrodynamic meters,

will require new measurement support with the

advent of electronic meters which will be

used for demand and time of day metering purposes and may eventually employ telemetry

techniques for instant transmission of con- sumption information to the utilities.

There are a few common problems with widespread effects on the entire system. Among

them are:

(a) a lack of availability of "how-to-doit" measurement information throughout the

system;

(b) a shortage of manpower with specific

metrology training and a resulting widespread

lack of sophistication in measurement technology as practiced;

(c) heavy emphasis on "traceabil ity",

largely fostered by Department of Defense

quality requirements, which causes much attention to be focused on equipment specifications

and calibrations rather than measurement technology. This tends to slow the development

of new and improved methods of providing mea- surement support where it counts, on the production line or at the weapons system; and

(d) a lack of recognition of the formal

metrology structure as an asset rather than

a required artifact in a large percentage of

industry.

Specific recommendations resulting from

this study are:

57
General In support of the power industry

Develop a mechanism to foster and support

the use of Measurement Assurance philosophy

and techniques within industry to provide subsistence to measurements made for quality control, manufacturing, or maintenance purposes.

Develop more formal contact between the

Electricity Division and the instrumentation

industry, perhaps through the aegis of the

Scientific Apparatus Manufacturers Association.

Establish national standards and improved

measurement methodologies for the ac measurement of conductivity in metals in support of

non-destructive testing in industry.

In support of electronics

Investigate new technology for providing

measurement support for automatic test systems, perhaps in conjunction with Defense

Department efforts in this area.

Examine microprocessor technology and the

applications of microprocessors to instrumentation to lay the foundation for support for

future generations of sophisticated "smart"

instruments.

Provide improved methods for the measurement of ac voltages at low amplitudes in the

sub-audio frequency range and the measurement

of impedance in the upper audio range for the

support of vibration and communications instrumentation respectively.

Provide for development of measurement

methodologies for the characterization of the

insulating properties of various materials

and systems at high voltages and under various conditions and configurations (such as for superconducting cables).

Contribute to the development of electronic

watthour meters to develop the new standards

and measurement techniques necessary to their

support.

Promote the use of field calibrations and

measurement assurance programs in the area

of high voltage.

Continue research in high voltage impulse measurements and develop mechanisms

to disseminate the resulting technology to industry.

Develop new approaches and devices for the

measurement of voltage, current, and power in

high voltage dc transmission systems.

Investigate methods for measurement of the

extremely high currents which will be carried

by superconducting cables.

Develop methods for the precise measurement of electric fields in regions of extreme

nonlinearity for environmental protection and

safety testing purposes.

58
APPENDIX A

THE MEASUREMENT SYSTEM STUDY

The starting point in efforts to date has

been the group of organizations constituting

our calibration clientele. The general plan

for this study is outlined below:

a. Identify calibration clients and

associated economic data.

b. Classify clients by industry or major

product(s)

.

c. Select sample of clients to visit to determine measurement needs, technical problem areas, and organizational structure.

d. Identify corporations and industries

who are not clientele but who are engaged

in the same kinds of endeavors.

e. Sample non-client organizations of

maximum economic, social, and political importance to determine the methods employed

to achieve product quality -surance in

those organizations.

f. Garner detailed it. cion about

specific needs via intervie. , workshops,

etc.

Using information supplied by the Office

of Measurement Services (NBS), a listing of

all users of our calibration services in FY

72 has been compiled. The clients on this

list were then classified in one of the categories shown subsequently. Each organization was assigned up to three numbers

representing one primary and two secondary

activities. These v/ere based on personal

knowledge and on descriptions found in Standard arid Fear's IrAex. In addition, annual income figures from either the Starndjord

and Poor's Index or the Dun and Bradstreet

Million Dollar and Middle Market Indicies

were gathered for each customer. This information was added to that supplied on punch

cards by the Office of Measurement Services

and sorted. There were three sorts made, one by each of the primary and secondary

activities of each company. As a result of

the first sort, 52 companies are unclassified; 17 are in the aerospace industry;

49 manufacture instrumentation; 21 manufacture components; 43 are power industry-related; 7 are universities; 9 are other

Federal government agencies; and 32 are in

general manufacturing, for a total of 230

companies. A meeting of the study authors

was held on the receipt of these printouts

and a number of pertinent decisions were

made.

It was decided that a separate substudy

should be made of the power industry in view

of the percentage of the Division's clientele

it represents, the annual income it has, the

role it plays in our society, and the energy

crisis. The chief of the High Voltage Section undertook this substudy because of the

mission of the Section and his personal contacts within the electric power industry. A minimum sample size for each of several

categories was decided upon, based upon the

perception of the degree of impact NBS has

on each category and knowledge of the uniformity of measurement technology within the

category. The table below gives each of

these categories and the sampling size

chosen.

SAMPLE SIZE FOR CLIENTS

Category Sample Size

201 Precision Apparatus 100%

212 DC-LF Test Equipment 100%

100 Aerospace Industries 25%

209 Systems 10%

600 Other Agencies 100%

300 Component Manufacturers 2 of each subcategory

800 Calibration Laboratories As many as possible

The type of information which would be

sought of each sample was also discussed.

Answers to the following questions would be

sought:

a. What are the corporate quality control

organizational and technical structures?

b. Do you perform calibrations for other

organizations? How Much? For whom?

c. What is the name of the key researcher

in your company (Chief Scientist, perhaps)?

d. What is the annual expenditure on electrical measurements in your company?

How is it spent?

e. What measurement areas are most critical to your final product?

f. What measurement or measurementrelated problems do you have? Can NBS help?

g. What products are most critically

affected by measurements?

h. Would you be aided by improved or new

NBS services? What areas? Why?

i. What are the desired accuracies of

measurements at the end item? Who determines

these? Why are they what they are? What are

the consequences of not supplying the desired

accuracies?

j. Are you a military contractor? Are you subject to any regulatory agency policies?

59
It also seemed desirable to inform our contact, in advance of a visit by Division

personnel, of the capabilities of the NBS and

especially of the Division. Accordingly, an effort has been made to inform him by letter

or telephone of the specific purpose of the

visit so he could be prepared. It would be

difficult, otherwise, to qet past the cor- porate standards laboratory into the ap- plied areas of the system.

In gathering information from Standard

and Poor's Index and from the two publications of Dun and Bradstreet, it became

apparent that NBS has direct contact with

only a small percentage of the electrical

measurement system. It had been originally

decided that the Division must sample that

part of NEMS it does not normally interact

directly with. To do that the services of

Dun and Bradstreet were enlisted. The list

of clients previously mentioned was expanded

to include FY 73 clients and each plant location served. The local office of Dun and

Bradstreet determined the primary Standard

Industrial Classification (SIC) Code for

each company of a large sample. After discarding 17 of the 35 SIC codes thus obtained

due to obvious lack of relevance, a contract

was issued to Dun and Bradstreet to supply

the Division with Dun's Market Identifiers

for each of the companies in their file

having one of the 16 primary SIC codes and more than 20 employeeSo Information has been

supplied for 12,865 companies in the United

StateSo

We hope to obtain additional samples by

interrogating people who visit the Division.

In the past four years over 90 plant locations have been visited by Electricity Division personnel. Before this study was formally initiated, the purpose of most

visits was the discussion of measurement

problems. The next pages contain a representative list of locations visited.

Technical forecasting is always involved

in program planning, whether explicitly or implicitly. In the past, technology forecasting for this Division has been done by

two groups of experts, one (unorganized)

within the Division and the other outside

of the Division, the NAS/NRC/NAE Advisory

Panel.

The technology forecasting portion of

this study has been accomplished by doing a formal review of trends and forecasts already published for the electrical field by

trade and industrial associations, professional societies, and other government

agenci es

.

SAMPLE LIST OF PLACES VISITED

Associated Engineering Company

Matthew, NC 29105

Autonetics

Rockwell International

3370 Miraloma Avenue

Anaheim, CA 92803

Ball Brothers Research Corporation

P. 0. Box 1062

Boulder Industrial Park

Boulder, CO 80302

Baltimore Gas and Electric Company

531E Madison Street

Baltimore, MD 21203

Beckman Instruments, Inc. 2500 Harbor Boulevard

Fullerton, CA 92634

Bendix Environmental Science Division

1400 Taylor Avenue

Baltimore, MD 21204

Boeing Company

Aerospace Division

P. 0. Box 399

Seattle, WA 98124

Brookhaven National Laboratory

Brookhaven, NY

Dickson Electronics Corporation

P. 0. Box 1390 Scottsdale, AZ 85252

Duke R3wer Company

P.O. Box 2178

Charlotte, NC 28201

Fairchild Semiconductor

4300 Redwood Highway

San Rafael , CA 94902

Ford Motor Company

21500 Oakwood Boulevard

P. 0. Box 1704

Dearborn, MI 48121

General Electric Company

Ordnance Systems

100 Plastics Avenue

Pittsfield, MA 02101

Global Associates

Mississippi Test Facility

Bay St. Louis, MS 39520

Hewlett Packard Company

815 SW 14th Street

Loveland, CO 80537

50
Hewlett Packard Company

Automatic Testing Division

Mountain View, CA

Hewlett Packard Company

Microwave Division

Palo Alto, CA

Honeywell Industries

5558 Port Royal Road

Springfield, VA 22151

Honeywell, Inc. Government & Aeronautical Products Div.

2600 Ridgway Parkway

Minneapolis, MN 55413

Honeywell, Inc. Test Instruments Division

4800 East Dry Creek Road

Denver, CO 80217

Honeywell, Inc. 5303 Shilshole Ave., NW Seattle, WA 98107

Hughes Aircraft Company

Centinela & Teale Streets

Culver City, CA 09230

IBM Systems Manufacturing Division

Monterey & Cottle Roads

San Jose, CA 95193

Jet Propulsion Lab

California Institute of Technology

4800 Oak Grove Drive

Pasadena, CA 91103

John Fluke Manufacturing Co.

P. 0. Box 7428

Seattle, WA 98133

Julie Research Laboratories

211 West 61st Street

New York, NY 10023

Leeds & Northrup Company

Sumneytown Pike

North Wales, PA 19454

Linde Corporation

Tarrytown, NY

Lockheed Missiles & Space Company

P.O. Box 504

Sunnyvale, CA 94088

Martin Marietta Corporation

Denver Division

P. 0. Box 179

Denver, CO 80210

Mel par

Division of LTV El ectrosystems

7700 Arlington Boulevard

Falls Church, VA 22046

3M Company

3M Center

Bldg. 216-lS

St. Paul, MN 55101

Newark Aerospace Guidance & Metrology Center

Newark Air Force Station, OH 43055

Optimation Industries

Northridge, CA

Patuxent Naval Air Station

Patuxent River, MD 20670

Oak Ridge National Laboratory

Oak Ridge, TN

Philadelphia Electric Company

2301 Market Street, N4-1

Philadelphia, PA 19103

Rosemount Engineering Company

12001 West 78th Street

Eden Prairie, MN 55343

Shallcross Manufacturing

Preston Street

Selma, NC 27576

Sperry Rand Corporation

UNIVAC Division

Univac Park

P.O. Box 3525

St. Paul, MN 55101

TRW Systems Group

One Space Park

Redondo Beach, CA 90278

United Air Lines

San Francisco International Airport

San Francisco, CA 94128

Westinghouse Electric Corporation

P. 0. Box 1637

Bal ti more- Washington International

Ai rport

Baltimore, MD 21303

Westinghouse Electric Corporation

Astronuclear Laboratory

P. 0. Box 10864

Pittsburgh, PA 15236

Westinghouse Electric Comp^'Ty

Raleigh, NC

61
CATEGORIES OF CALIBRATION CLIENTELE

100 Aerospace Industry

101 Prime Contractors (Airframe)

102 Subcontractors (Miscellaneous)

103 Subcontractors (Propulsion)

104 Subcontractors (Guidance)

105 Consultants

200 Instrumentation

201 Precision Apparatus Manufacturers

202 DC-LF Test Equipment Manufacturers

203 Analog-to-Digital , Digital-to-Analog

Conversion Equipment

204 Medical Instrumentation

205 Process Control Computer and Data Acquisition Products

206 Nuclear Instrumentation

207 Communications Equipment

208 Recording Equipment

209 Systems

210 Chemical Instruments

211 Pollution Monitoring Equipment

212 Microwave Test Equipment

213 Temperature Measuring Equipment

300 Component Manufacturers

301 Resistors

302 Capacitors

303 Inductors

304 Solid State Reference Devices

305 Integrated Circuits

306 Switchgear

307 Electron Tubes

308 General

309 Batteries

400 Power Industry Related

401 Transmission Monitoring Equipment

402 Generating Equipment Manufacturing

403 Power Measuring Equipment

404 Power Generation

405 Consultants

500 Universities

600 Other Government Agenices

601 Army

602 Navy

603 Air Force

604 NASA

605 Bonneville Power Administration

606 Public Health Service

607 FDA 608 NOAA

609 FAA 610 EPA

611 TVA

612 Bureau of Mines

613 ERDA

700 General Industry

701 Automobile Industry

702 Waste Management

703 Electric Motors

704 Electric Generators

705 Metals Products

706 Nuclear Research

707 General Research

708 Computer Manufacturing

709 General Manufacturing

710 Chemicals

711 Consumer Products

712 Services

713 Sales

800 Calibration Laboratories

62
APPENDIX B

NBS PRIMARY AND WORKING ELECTRICAL STANDARDS

The following identifies the number and type of standards used to maintain the various

electrical units and working standards for the dissemination processes. The term "primary"

as used below refers not only to those standards used to maintain the basic electrical

units, but to those which enable measurements to be made under conditions differing from

those under which the basic units are maintained. Examples of the latter are standard

resistors especially designed for stable characteristics at very high currents. The list

does not contain measurement apparatus (except when such apparatus embodies a unit), or intermediate standards used for scaling, or the check standards used to maintain statistical

control over the various measurement processes.

Sec. 1. RESISTANCE

Primary Standards

5 Thomas (NBS) One-ohm Standard Resistors

Working Standards used at Low Currents (0.01 W or less]

10

1010

101010

101010

10

10

1010

10

10

10^

10^

ohm 4 Rei chsanstal

t

4 Reichsanstalt

4 Reichsanstalt

4 Reichsanstalt

[comme rcial

[commercial

[commercial

[commercial

Standard Resistors

Standard Resistors

Standard Resistors

Standard Resistors

5 Thomas (NBS) One-ohm Standard Resistors (The

15 Thomas (commercial and NBS) One-ohm Standard

4 Rosa (commercial) Standard Resistors

Primary Group)

Resistors (MAP)

2 Special

2 Special

2 Special

2 Special

ial

10'

10

10

10

10

10

10

10

11

1213

14

15

high-stability (commercial) Standard

high-stability (commercial) Standard

high-stability (conunercial ) Standard

high-stability (commercial) Standard

4 Special, high-stabil ity (commercial ) Standard

4 Special, high-stability (commercial) Standard

4 Rosa (commercial) Standard Resistors

4 Rosa (commercial) Standard Resistors

2 Wirewound (commercial) Standard Resistors

2 Film (commercial) Standard Resistors

2 Series/parallel (NBS) Resistance Boxes

2 Wirewound (commercial) Standard Resistors

2 Film (commercial) Standard Resistors

2 Series/parallel (NBS) Resistance Boxes

2 Film (commercial) Standard Resistors

1 Series/parallel (NBS) Resistance Boxes

1 Series/parallel (NBS) Resistance Box

1 Series/parallel (NBS) Resistance Box Scott (NBS) Capacitive Discharge Apparatus

Scott (NBS) Capacitive Discharge Apparatus

Scott (NBS) Capacitive Discharge Apparatus

Scott (NBS) Capacitive Discharge Apparatus

Scott (NBS) Capacitive Discharge Apparatus

Resi stors Resistors (MAP)

Resistors

Resistors (MAP)

Resistors

Resistors

Primary Standards for Resistance at High Currents

lO"-" ohm

4 10

10

-3

1010

10^

-2

-1

1 Wolfe (commercial) High Current

1 Reichsanstalt (commercial) High

1 Wolfe (comnercial ) High Current

1 Reichsanstalt (commercial) High

1 Wolfe (commercial) High Current

1 Reichsanstalt (commercial) High

3 Reichsanstalt (commercial) High

3 Reichsanstalt (commercial) High

2 Reichsanstalt (commercial) High

1 Thomas (NBS) Standard Resistor

Standard

Current

Standard

Current

Standard

Current

Current

Current

Current

Standard

Standard

Standard

Standards

Standards

Standards

All except Primary Low Current Standards are also Working Standards

63
Sece 2. PRECISION APPARATUS

Primary Standards

Primary Low Current Resistance Standards (Sec. 1)

2 NBS-specified (commercial) Universal Ratio Sets

1 Dunfee-Dziuba (NBS) Primary Volt Ratio Standard

Two-stage (NBS) Inductive Voltage Divider

One-stage (commercial) Inductive Voltage Divider

Working Standards

2 NBS-specified (commercial) Universal Ratio Sets (same as above)

1 Dunfee-Dziuba (NBS) Primary Volt Ratio Standard (same as above)

2 Dziuba (NBS) Portable Volt Ratio Standards

1 Wheatstone (commercial) Bridge

1 Direct Reading Ratio Set (commercial)

1 Direct Reading Ratio Set (NBS)

12 Rosa (commercial) 100-k ohm Resistors

1 Two-stage (NBS) Inductive Voltage Divider (same as above)

1 One-stage (commercial) Inductive Voltage Divider (same as above)

Sec. 3. IMPEDANCE MEASUREMENTS

Primary Standards

1 Cutkosky (NBS) Valculable Capacitor

, 10 Cutkosky Fused-Silica Dielectric Capacitors (10 pF)

Primary Low Current Resistance Standards (See Sec. 1) Working Standards for Measurements of Capacitance

1 Cutkosky (NBS) Fused-Silica lO-pF Capacitor

1 Type-12 (commercial) Capacitance Bridge

5 Nitrogen Dielectric (commercial) Standard Capacitors

Working Standard for Measurement of Inductance

1 Maxwell -Wei n (NBS) Bridge

Sec. 4. VOLTAGE

Primary Standard

Denenstein-Finnegan (NBS) AC Josephson Effect Apparatus

Working Standards

2 Cutkosky (NBS) Standard Cell Enclosures

1 NBS Oil Bath (NBS 11)

8 (commercial) Standard Cell Enclosures (MAP)

SeCo 5. AC-DC TRANSFER STANDARDS

Primary Standards

12 NBS-specified (commercial) Singl e- junction Evanohm Thermoelements

;

, 2 NBS-specified (commercial) Multi-junction Evanohm Thermoelements

Working Standards

2 sets (NBS) Coaxial Voltage Converters

2 sets NBS-specified (commercial) Thermal Current Converters

1 (NBS) Wattmeter

1 Yokagawa (commercial) Wattmeter

64
Sec. 5. TRANSFORMERS

Voltage

Primary & Working Standards

Petersons (NBS) High Voltage Current Comparator Bridge

Current

Primary Standards

2 Souders (NBS) Two-stage Transformers

Working Standards

3 Compensate'd (NBS) Current Comparators

Sec. 7. HIGH VOLTAGE & ENERGY

DC Voltage Dividers

Primary Standards

Primary Resistance Standards (Sec. 1)

3 Park (NBS) High Voltage Dividers

Working Standards

3 Park NBS High Voltage Dividers (same as above)

10 Rosa (commercial) Standard Resistors

DC Kilovol tmeters

Primary Standards

Primary Resistance Standards (Sec. 1)

Primary Voltage Standards (Sec. 4)

3 Park (NBS) High Voltage Dividers

Working Standards

3 Park (NBS) High Voltage Dividers (same as above)

1 (commercial) Digital Voltmeter

AC Voltage Dividers

Primary & Working Standards

Petersons (NBS) High Voltage Current Comparator Bridge

AC Kilovol tmeters

Primary Standards

Primary Voltage Standards (Sec. 4)

Petersons (NBS) High Voltage Current Comparator Bridge

Working Standards

Petersons (NBS) High Voltage Current Comparator Bridge (same as above)

1 (commercial) Electrostatic Voltmeter

65
Sec. 7. HIGH VOLTAGE & ENERGY (Continued)

Capacitors (High Voltage)

Primary Standards

Primary Capacitance Standard (Sec. 3)

Hillhouse (NBS) High Voltage Capacitor

Working Standards

2 Nitrogen Dielectric (commercial) Standard Capacitors

Watthour Meters

Primary Standards

Primary Voltage Standards (Sec. 4)

Primary Resistance Standards (Sec. 1) Primary Time Interval Standards

Working Standards

Lentner (NBS) Current Comparator Energy System

4 Rotating (commercial) Watthour Meters

Impulse Dividers

Primary Standards

Primary Resistance Standards (Sec. 1)

Primary Voltage Standard Resistive Divider (Sec. 4)

Working Standard

Kerr Cel 1 Apparatus

66
APPENDIX C

"CRITICAL ELECTRICAL MEASUREMENT NEEDS AND STANDARDS FOR MODERN ELECTRONIC INSTRUMENTATION"

WORKSHOP REPORT ABSTRACT, PREFACE, AND LIST OF ATTENDEES

Abstract

Recognizing the proliferation of sophisticated modern electronic instrumentation in

the field of electrical measurements, the

Electricity Division of the National Bureau

of Standards recently initiated a new prog- ram in the general area of dynamic measurements and standards in support of such instrumentation. Recognizing further that the

vastness and complexity of the field v;ould require, at the earliest stages of the program, identification of the most critical

problem areas, the Electricity Division held

a workshop on 23 and 24 September 1974, at

the Bureau's Gaithersburg site, to assist it

in ascertaining just what these areas in fact

were. The basic idea of the Workshop was to bring together a broadly representative group

of some 25 leading manufacturers and prime

users, working in a free and open atmosphere,

in order to have them delineate the present

and future critical support needs in the

field of dynamic electrical measurements for

modern electronic instrumentation, v/ith em- phasis on physical standards, standardized

measurement methods, new calibration and

measurement assurance services, relevant

data, and, most important, new measurement

methodologies. The overall objectives of

the Workshop were generally met, and a num- ber of significant specific programs and

projects consistent with the mission of the

Electricity Division were identified. Three

categories broadly cover the needs as defined

at the Workshop:

1. The need to introduce time as a measurement parameter has resulted from the re- quirements of automatic test and control

systems. Specific areas considered critical

are:

a. Pulsed component measurements.

b. Dynamic performance characterization

for modern signal conditioning and data con- version devices: Digital-to-analog and

analog-to-digital converters, sample-andhold amplifiers, comparators, etc. Required

measurements include settling, aperture and

acquisition times. Basic new capabilities

will be needed, including precision, non- sinusoidal waveform generation and "standard"

digital-to-analog converters.

c. Methodologies and techniques for

characterizing precision ac and dc sources

and measurement devices with respect to settling time.

2. The emergence of measurements into the

"real world" or the production line via the

automatic system has introduced a host of new parameters. Areas requiring significant

effort include:

a. Investigation of transportable stan- dards for \el idation of static and dynamic

system performance: ac and dc voltage, impedance, pulses, settling times.

b. Techniques for characterizing sources

and measurement devices with respect to switched or dynamic loading.

c. Prediction of long-term performance,

reliability and lifetime from short-term

evaluation for a host of passive components,

semiconductors, and signal sources.

d. Noise standards and methodologies.

e. Continuing effort to improve trans- portable dc standards and dissemination at higher voltage levels.

f. Characterization of the ac line voltage-waveforms, under- and over-voltages,

transients, dynamic impedance, etc.

g. Inclusion of a capability for environmental control and variation for devices

and instruments under calibration, in all work undertaken by the Bureau.

h. Extension of Measurement Assurance

Programs (MAP's), especially into the above

new areas.

3. Recent work at the leading edge of mea- surement technology in electronics has

resulted in the need for new, or higher

accuracy, measurements. For example:

a. Increased dependence on capacitors as storage devices has m.ade dielectric hysteresis a parameter of importance. Significant

measurement work should be started in this area.

b. Phase difference measurements to ex- tremely high accuracies are needed to calibrate industrial instrumentation.

c. Higher accuracy power measurements,

particularly for non-sinusoidal waveforms,

are needed to calibrate instrumentation in

the field.

67
d. Non-sinusoidal, high crest-factor

precision signals are needed to calibrate

true RMS converters and meters.

e. High accuracy electronic instrumentation requires reduction in ac calibration

uncertainties to 10 ppm, at least over the

audio range.

Longer-term, "frontier" areas in each of

the above groups were also identified. They

are not specified in the above listings since

they involve work at still more basic levels,

on ground that is presently terra incognita.

Nevertheless, they furnish insight into the

overall technical/philosophic climate, and

are useful for that reason. Items in this

category include:

1. Measurement problems in systems, including effects of history, measurement interactions, self-calibration, etc.

2. Evaluation and standardization of system

software.

3. Calibration of medical equipment.

4. Replacement of standard cells.

5. Replacement of thermal ac/dc converters.

6. Non-swept but broad-response measurements

- impulse, noise, other.

7. Basic work on the physics of dielectric

absorption; component drift; device noise;

failure mechanisms; switches; and relays.

8. Provision of improved measurement accuracy for virtually all dynamic measurements,

at the wafer probe level.

In addition to the identification of these

specific and general needs, the Workshop provided strong evidence that both the manufacturing and user communities in the electronic

instrumentation field look to the Electricity

Division to provide the technological leadership in these newer areas that it has previously furnished in the more traditional

electrical measurement areas. Indeed, there

was a good deal of support for the idea of

keeping the electronics community informed

of Division work-in-progress, with emphasis

on projects targeted by the Workshop.

Keywords: Data conversion; dynamic measurements; electrical measurements;

electronic instrumentation; signal

conditioning; system; time domain.

Preface

It is apparent that the continued, or- derly growth of the electronics industry is increasingly hampered by a lack of standards

and methodologies in a number of crucially

important electrical measurement areas.

The explosive growth of electronics during the last decade has brought with it a host of unsolved measurement problems. Yet . at this critical historical juncture, electronics is a key technology in the prospective solutions to some of society's major

outstanding concerns including energy,

pollution, and productivity, to name but

three. It is, therefore, mandatory that a responsible, capable organization without

specific industrial affiliation, assume a leadership role in providing the necessary

measurement standards and methodologies, as well as in establishing new electrical mea- surement programs for which need is both

broad and identified, but whose implementation by specific industrial organizations

would be impractical.

The Electricity Division of the National

Bureau of Standards has traditionally dealt

with the measurement and generation of electrical signals in the dc to 30 kHz range, as well as with the properties of electrical

components in that range. In effect, with

the one possible minor (philosophical) ex- ception of phase, the Division has devoted

itself to ampl i tude or magni tude measurements for the various electrical parameters.

Some of these have been generated and/or

transmuted by mechanical and electro-mechanical means, others more recently by electronic, and others in future undoubtedly by

light, but the electrical (usually amplitude)

parameters have had similar properties and

required the same disciplines for measurement.

Now, automatic systems for test, process

control, medical applications, and so forth

are using electrical quantities at higher

speeds than heretofore. Ten years ago a precision dc, dialable 6- or 7-digit source did

not need a settling time specification; to- day, "programmable" sources have such specifications, since the system architect must

know how long it will take for this stimulus

to settle to within a given accuracy. In many instances total system speed, hence

all-important throughput, dollar payback

and/or justification, will be limited by

such settling times.

Thus, tD precision electrical measurements

has been added the temporal parameter. In a manner analogous to the changeover from frequency to time domain work in filter synthesis in the early sixties, measurement must

now turn from exclusive attention in the

68
frequency domain, to characterization involving time as well, e.g., settling time to x microvolts in y microseconds is an electrical, analog, amplitude measurement with the

time factor added.

The Workshop which this report describes

and summarizes, is the means chosen by the

Electricity Division to establish direct

communication with key elements of the electronics industry among both manufacturers

and users, for the purpose of ascertaining

the industry's electrical measurement needs,

both general and specific. The enthusiasm

engendered by the Workshop itself attests to the fact that the time has come for leadership and action: In spite of difficult times

and severe cost pressures, 24 outstanding

organizations were willing to send top personnel to the 2-day Workshop, disrupting

busy schedules, and at considerable financial

expense.

This report on the Workshop results must

inevitably reflect some of the author's technical biases, developed over the course of

25 years of varied design, management and

consulting experience in the fields of electronics, measurements and standards. During

that interval the technology has made tre- mendous advances, so that in many areas it

is virtually unrecognizable in comparison

with its major jumping-off point directly

following the Second World War. Indeed, some of those advances are the direct result

of work accomplished at or backed up by programs of the Electricity Division of the NBS,

notably during what might be termed the mea- surement "explosion" of the decade of the

sixties.

By the same token, it is hoped that the

author's general breadth of design and mea- surement exposure during those same years of

experience, plus long-standing and continuing interactions with the Bureau, have provided a balanced view of the Workshop results

in this report. If this has been accomplished, the Division programs resulting

from the Workshop can form the basis for new

and crucially-important electrical measurement technology for electronics in the forthcoming decade.

It is impossible to convey here the ex- citement felt by virtually all participants

during the Workshop which helped to make the

author's task as moderator both rewarding

and enjoyable. The excitement was undoubtedly due in part to the professional challenge offered by the opportunity for open,

free-swinging exchange among the outstanding

group of participating engineers and scientists. But it clearly reflected, as well,

the participants' recognition of the large

and important work that so critically needs

to be done, and their enthusiastic reception

of the role of the Electricity Division in

grasping the initiative to establish rele- vant new programs on a priority basis.

There was, in short, the excitement result

ing from the pervasive feeling of being part

of an undertaking that was both significant

and effective.

I should like to express my thanks to the Electricity Division and to Dr. Barry N. Taylor in particular, for giving me the opportunity to contribute to this important

work. I should also like to add my own personal thanks to the participants and their

organizations, as it is they who are truly

responsible for the Workshop's tuccess.

Peter Richman

Consulting Engineer

69
WORKSHOP

Mr. Loyle E. Baltz

Principal Test Engineer

Ford Motor Company

Allen Park, MI

Mr. Eduard F. Boeckmann

Chief Engineer

Angstrohm Precision, Inc. Hagerstown, MD

Mr. Warren C. Collier

Manager, TM 500 Design, Engineering

Tektronix, Inc. Beaverton, OR

Mr. Thomas J. Coughlin

Product Engineering Manager

Component Systems

General Radio Company

Concord, MA

Mr. Jack D. Dougherty

Chief, DC & Low Frequency Standards

Laboratory

Newark Air Force Station, OH

Mr. George W. Herron

Senior Engineer

Keithley Instruments, Inc. Cleveland, OH

Mr. Donald E. Lawrence

Project Manager

Hewlett-Packard Company

Sunnyvale, CA

Mr. David R. Ludwig

Vice President

Advanced Development and Planning

Teledyne Phil brick

Dedham, MA

Mr. Edward P. Mueller

Biomedical Engineer

Food and Drug Administration

Rockville, MD

Mr. William A. PI ice

Senior Project Staff Engineer

Honeywell, Inc. St. Louis Park, MN

Mr. Robert C. Raybold

Head, Institute for Basic Standards

Automation Group

National Bureau of Standards

Washington, DC .

"

Mr. Bruce A. Renz

Head, Systems Measurement Section

American Electric Power Service Corp. New York, NY

ATTENDEES

Mr. David B. Schneider

Calibration Product Specialist, ATE John Fluke Manufacturing Co., Inc. Seattle, W\

Mr. Frederick B. Seeley

Chief, Electromagnetics Engineering Branch

U. S. Army Metrology and Calibration Center

Redstone Arsenal , AL

Mr. Robert M. Shaw

Fellow Engineer

Westinghouse Electric Corporation

Baltimore, MD

Mr. Lewis R. Smith

Engineering Manager

Analog Devices, Inc. Norwood, MA

Mr. Douglas C. Strain

President

Electro Scientific Industries, Inc. Portland, OR

Mr. Robert P. Talambiras

Corporate Director of Advanced Development

Analogic Corporation

Elmwood Park, NJ

Mr. David S. Terrett

General Manager, Research & Development

ADT Security Systems

New York, NY

Mr. James C. Tripp

Engineering Supervisor

Linear Test Development Group

National Semiconductor Corporation

Santa Clara, CA

Mr. Robert H. Verity

Manager, Standards Laboratory

Leeds & Northrup Corporation

North 1^1 es, PA

Mr. Wil 1 iam R. Wal ters Chief Engineer

Codi Semiconductors

Fairlawn, NJ

Mr. F. Mansfield Young

Director of Engineering

Teradyne, Inc. Boston, MA

Mr. Ray A. Zuck

Director of Operations

Geometric Data Corporation

Wayne, PA

70
APPENDIX D

STANDARDS AND CALIBRATION LABORATORIES

CODE: Type of Service

Type of Organization;

S - Primary standards

C - Calibrations

B - Both

T - Testing

C - Corporate laboratory

I - Instrument manufacturing

P - Calibration & metrology lab solely or mostly

No code indicates exact nature of service not known to authors.

Laboratory

AEL, Colmar, PA AEL Communications, Lansdale, PA AIL Technological, City of Industry, CA AVCO Corporation, Charleston, SC AVCO Corporation, Lycoming Div., Stratford, CT

AVCO Corporation, Richmond, IN Aerojet Nuclear, Idaho Falls, ID Ailtech Cutler Hammer Co., Farmingdale, NY Airtron Div., Litton Systems, Morris Plains, NY

Al-1 Systems, Morristown, NJ Allis Chalmers Mfg. Co., Milwaukee, WI American Electronic Labs, Lansdale, PA American Geophysical & Instrumentation, Gardena, CA American Instrument Service, Philadelphia, PA Ark Electronics, Willow Grove, PA B&K Instruments, Cleveland, OH BLH Electronics, Waltham, MA Ballantine Laboratories, Boonton, NJ Ball Brothers Research, Boulder, CO Bath Iron Works Corporation, Bath, ME Beckman Instruments, Fullerton, CA Beech Aircraft Corporation, Wichita, KS Bell Aerospace Co., Buffalo, NY Bendix Corporation, Teterboro, NJ James G. Biddle Co., Plymouth Meeting, PA Blake Electronics, Inc., Greendale, WI Boeing, Wichita, KS Boeing Aerospace Group, Seattle, WA Brunswick Engineering, Inc., Northbrook, IL Burroughs Corporation, Paoli, PA Calibration Central, Alexandria, VA Certified Calibration Labs, Inc., Philadelphia, PA Collins Radio Co., Cedar Rapids, lA Communications Satellite Corp., Clarksburg, MD Computer Diode Co., Fairlawn, NJ

Member

NCSL

Type of

Service

Code

Type of

Organization

Code

Sources: A Directory of Standards Laboratories, 1974 Edition, National Council of

Standards Laboratories, Washington, DC, 1974.

Electronics '75 Buyers' Guide, McGraw-Hill, New York, NY, 1975. eem 75/76, electronic engineers master catalog. United Technical Publications,

Garden City, NY, 1975.

Electronic Design's Gold Book, Hayden Publishing Company, Rochelle Park, NJ, 1975.

71
Laboratory

Comtel Corporation, Detroit, MI Cox & Co., New York, NY DBA Systems, Melbourne, FL Dalmo Victor, Belmont, CA Davidson Optronics, West Covina, CA Dayton T. Brown, Inc., Bohemia, NY Detroit Edison Co., Detroit, MI Dillon, W. C. & Co., Van Nuys, CA Douglas Instrument Lab, Boston, MA

Dow Chemical Co., Rocky Flats, CO EG&G, Albuquerque, NM '

' " EG&G, Las Vegas, NV

E. I. DuPont de Nemours, Aiken, SC EIL Instruments, Timonium, MD Electrical Instrument Service, Mt. Vernon, NY Electrical Science Services, Cambridge, MA Electrical Testing Labs, Inc., New York, NY Electro Scientific Industries, Portland, OR Electronic Marketing Associates, Kensington, MD Eppley Laboratories, Newport, RI E-Systems, Dallas, TX Fairchild Space & Electronics, Germantown, MD Fischer/Porter Co., Warminister, PA John Fluke Mfg. Co., Seattle, WA Foxboro Co., Foxboro, MA Gage Corp., Philadelphia, PA General Dynamics, Groton, CT General Dynamics, Quincy, MA General Dynamics, San Diego, CA

General Electric, Bay St. Louis, MS General Electric, Dallas, TX General Electric, Pittsfield, MA

General Electric, Schenectady, NY General Electric, Seattle, WA General Electric, Syracuse, NY General Electric Instrumentation, Inglewood, CA

General Environments Corp., Morton Grove, IL GENRAD, West Concord, MA Greentron, Inc., Greenville, SC Guildline Instruments, Inc., Larchmont, NY H-B Instrument Co., Philadelphia, PA Hamilton Technology, Lancaster, PA Harris Intertype, Melbourne, FL Hercules Inc., Magna, UT Hewlett-Packard Co., Palo Alto, CA Hewlett-Packard, Santa Clara, CA Hoffman Engineering Corp., Old Greenwich, CT

Honeywel

1

, Inc., Aerospace Div., St. Petersburg, FL Honeywel

1

, Inc., Annapolis, MD Honeywel

1

, Inc., Burlington, MA Honeywel

1

, Inc., Chicago, IL Honeywel

1

, Inc., Cleveland, OH

Honeywel

1

, Inc., Denver, CO Honeywel

1

, Inc., Detroit, MI Honeywel

1

, Inc., Downey, CA Honeywel

1

, Inc., Hazelwood, MO Honeywel

1

, InCo, Fairborn, OH Honeywel

1

, Inc., King of Prussia, PA Honeywel

1

, Inc., Minneapolis, MI

Type of Type of

Member Service Organization

NCSL Code Code

c

X B C

c

X B C

c P

X B P X B C

B P

X C C

C C

X C C

X B c

X B p

X B p C

X B,T P

X B I C

B I X B c

C c

C

X B I X B c X C P X B c

C c

X B c X B c

C c

X B c X B c

C c X B c

S c

c P

X B I C P

X S I C I C c

X B c

X C c

C I B I C X C p C p C P

C p

C P

X B p

C P C P C P

C P

C P

B c

72
Laboratory

Member

NCSL

Type of

Service

Code

Type of

Organization

Code

Honeywell, Inc., San Diego, CA Honeywell, Inc., Springfield, VA Honeywell, Inc., Sunnyvale, CA

Honeywell, Inc., Westfield, NJ Hy-Cal Engineering, Sante Fe Springs, CA Hughes Aircraft, Culver City, CA Hughes Aircraft, Fullerton, CA

IIT Research Institute, Chicago, IL Incal Service Corp., Stanford, CT Infinite, Inc., Cape Canaveral, PL Inland Testing Labs, Inc., Morton Grove, IL Instrument Labs Corp., Chicago, IL Intergalactic Corporation, Salt Lake City, UT Julie Research Labs, New York, NY

KC Calibration Lab, Kansas City, KS Kahl Scientific Instr. Corp., El Cajon, CA Keithley Instruments, Cleveland, OH Key Instruments, Gardena, CA

LTI Research Foundation, Lowell, MA

Lab Instrument Service, Campbell, CA Lear Siegler, Santa Monica, CA Leeds & Northrup, North Wales, PA Lehighton Electronics, Lehighton, PA Librascope, Div. of Litton, Glendale, CA Lockheed Aircraft Service, Ontario, CA Lockheed-California, Burbank, CA Lockheed Electronics, Houston, TX Lockheed-Georgia, Marietta, GA Lockheed Missiles & Space Co., Sunnyvale, CA

3M Corp., St. Paul , MN Main Electronics, Wichita, KS Mancib Co., Burlington, MA Martin Marietta, Denver, CO Martin Marietta, Marietta, GA McDonnell Aircraft Co., St. Louis, MO McDonnell Douglas Astronautics, Long Beach, CA McDonnell Douglas Astronautics,

West Huntington Beach, CA Micro-Radian . Instruments , Seal Beach, CA JR Miles Corporation, Elk Grove Village, IL Montedoro-Whitney , San Luis Obispo, CA National Astro Labs, Burbank, CA National Camera, Inc., Englewood, CO New Era Products, Cleveland, OH Newport News Ship Building & Drydock, Newport News, VA New York Testing Labs, Westbury, NY North American Rockwell, Anaheim, CA North American Rockwell, Rocketdyne Div., McGregor, TX Nucleus Corp., Madison Heights, MI Ogden Technology Labs, Fullerton, CA Optronic Labs, Silver Spring, MD Ormond Inc., Sante Fe Springs, CA

PTS Electronics, Inc., Bloomington, IN Penn Airborne Products, Southampton, PA Pioneer/Instrumentation, Cleveland, OH QVS Inc., East Orange, NJ RCA, Gov't Services, Moorestown, NJ RCA International Service Corp., Camden, NJ RCA International Service Corp., Patrick AFB, FL

C C

C P

C P

C P

S P

B C

C C X B P

C P

C P X S P

C P

C

B I C

S P

B I C P X B P

cc c

X B I C

C C

C C X B C X B C

B C X B C X B C

C P

C P X B C

X B C

X B C X B C

X B C

C P

C

B P

B P

C

C P

c c

C P X B C

B C

C P

B P

C

C P

c

B I B P

C

B C

B C X B C

73
Type of Type of

Member Service Organization

Laboratory NCSL Code Code

Ram

Ramsey

Meter,

Engineering,

Inc., Ferndale,

Anaheim,

MI CA

' CCPP Raytheon Submarine Signal, Portsmouth, RI • X B C Reliance Electric Co., Cleveland, OH . C P Robertshaw Controls Co., Richmond, VA C

SSCO

Sanders

Rockwell

Rutherford

Standards

Associates,

Engineering

Research

Laboratory,

Products,

Nashua,

Co., Indianapolis,

Detroit,

NH

Rutherford,

MI

IN NJ

X CPCPBPB C Scientific Leasing Services, Lake Success, NY C

Simpson

Sensitive

Electric

Research

Co.,

Instruments,

Elgin, IL Mt. Vernon, NY CPC Singer Co., Kearfott Div., Little Falls, ND - X B C Sperry Electronic Tube Div., Gainesville, FL B C Stabro

States

Labs,

Electronic

Salt

Corp.,

Lake City,

Blundworth

UT Marine, Linden, NJ BPC C

Sweetman

Sunshine Scientific

Calibration

Instruments,

Services, Pennsauken,

Inc., Philadelphia,

NJ PA

X BBPP Systron Donner, Concord, CA . X S C TRW Systems, Redondo Beach, CA X B C Taylor Instrument, Process Control Div., Rochester, NY B C Technicians Unlimited, Lexington, MA _ C Teledyne Brown Engineering, Huntsville, AL • C C Teledyne McCormick Selph, Hollister, CA C C Teledyne Systems Co., Northridge, CA . X B C Texas Instruments, Houston, TX C P Thwing-Albert

Transducers, Whittier,

Instrument,

CA Philadelphia, PA CPC UNIVAC, Utica, NY ' ' X S C Union Carbide, Oak Ridge, TN X B C Varian, Palo Alto, CA X ' / S I Viking Labs, Sunnyvale, CA ' B C Westinghouse Electric Co., Baltimore, MD X B C Westinghouse Electric Co., Pittsburgh, PA X B C Weston Instruments, Newark, NJ . X B I

This listing of calibration and standards laboratories is not to be taken as an endorsement

by the National Bureau of Standards of laboratories included, or as an indication of the

quality of calibrations available from either listed or unlisted organizations.

74
APPENDIX E

TYPICAL MEASUREMENT SUPPORT STRUCTURES

On the following pages are representative functional diagrams of two corporations and

their measurement support structures. On the following page is depicted the structure by

which the U.S. Air Force, through a network of over 140 calibration facilities, provides

world wide measurement support for over $400 million worth of electronic test equipment

with which maintenance and operational support for weapons, communications, navigation,

guidance and medical systems are supplied.

75
-<

r- C

4-> O

S_ >-> _Q- 1^ r— QJ

It) O)

r

o

-O JD

O i- i- "D fO _l O) J3 CL SI— O O oO ->-

A

U1 C O Ol

z: Q

O O)

phera

ces sion

ri

can s

Group

S- > >

OJ OJ C- Q Q

A

th

Ame

-atioH'

1 u Y c

<U I/I o o cx o

input visi O >>•'- O 1/1 Q

Ol

S-

=J

t-J

(_)

O) s_

+-> -l-J fO oo

i_o +-) Q. sS- o

o Q.

(_) Q.

fT3 O -l-J Q- OJ h- CD

s-

(/I (0

0) 2:

A 4\ 4>

oo

o

Ol

1- on

•r- CO

o o

Q. CL

76
—> —>

r

zr

r QJ Hi c = s- O O

<u

s~

+-> u

S-

+-> -M

fO tn o

o o Q.

Q.

03o -i-J o. OJ >, E

1— (US-

(/) <o(U

—> >

•4-> O

^ o c ^

77
Measurement Tools from Instrument Industry

Federal Government

Legal Requirements

Naval Observatory

Washington, DC

Measurement Services from NBS Electricity Division - 211.00 Mechanica Division - 213.00

Heat Division - 221.00

Optical Physics Division - 232.00 Electromagnetics Division - 272.00 Time and Frequency Division - 273.00

Principles of Physics and Technical Literature

AIR FORCE MEASUREMENT

STANDARDS LABORATORY

(Operating Budget $4.^165.000)

Army Standards Laboratory

Redstone, AL

Over 140 Precision Measurement

Equipment Laboratories

(Operating Budget - $43,000,000)

Foreign Government Laboratories

Ethopia Korea Greece Malaysia

India Nat. China Indonesia Phillipine Islands

Iran Spain

Israel Thai land Jordon Turkey

Maintenance and Repair Depots

All Aircraft, Missile

Ground Test Equipment

Other U.S. Government,

Army, Navy, FAA Test

Equi pment

_ Jl

' TOTAL AIR FORCE BUDGET FOR FY 73:

I =^ $23,737,000,000

Air Force Metrology Structure - FY 73

78
REFERENCES

The International System of Units (SI), Nat. Bur. Stand. (U.S.), Spec. Publ . 330,

4Q pages (1972).

Thomas, J. A., Peterson, C, Cooter, I. E. , and Kotter, F. R., An Absolute Measurement

of Resistance by the Wenner Method, J. Res. NBS (U.S.), 43, No. 4 (1949) RP2025.

Cutkosky, R. D., New NMS Measurements of the Absolute Farad and Ohm, IEEE Trans.

Instrum. Meas. IM-23 , No. 4, 305-309 (Dec. 1974).

Cutkosky, R. D. and Lee, L. H. , Improved Ten-picofarad Fused-silica Dielectric

Capacitor, J. Res. NBS (U.S.), 69C (Engr. & Instr.), No. 3, 173-179 (July-Sept. 1965).

Field, B. F., Finnegan, T. F., and Toots, J.-, Volt Maintenance at NBS via 2e/h: A New Definition of the NBS Volt, Metrologia 9, No. 4, 155-156 (1973).

American National Standards Institute 1976 Catalog (Am. Nat. Stand. Inst., NY, 1974).

Harvey, G. F., editor, Standard and Practices for Instrumentation - Fourth Edition

(Instr. Soc. Amer. , Pittsburgh, PA 1974).

Electronic Engineers Master (United Technical Publications, Garden City, NY, 1974),

U.S. Industrial 1975 Outlook with projections to 1980, Department of Commerce,

432 pages (1975).

U.S. Industrial 1976 Outlook with projections to 1985, Department of Commerce,

465 pages (1976).

Evenson, K. M. , Wells, J. S., Peterson, F. R., Danielson, B. L. , Day, G. W. , Barger,

R. L., and Hall, J. L., Speed of Light from Direct Frequency and Wavelength Measurements of the Methane-Stabilized Laser, Phys. Rev. Lett. 29^, 1346 (1972).

Cohen, E. R. and Taylor, B. N., The 1973 Least-squares Adjustment of the Fundamental

Constants, Journal of Physical and Chemical Reference Data, 2^, No. 4, 663 (1973).

Richman, P., editor. Critical Electrical Measurement Needs and Standards for Modern

Electronic Instrumentation, Nat. Bur. Stand. (U.S.), Tech. Note 865, 74 pages (May

1975) . A Directory of Standards Laboratories - 1975 Edition (National Conference of Standards Laboratories, Washington, 1975).

Use of off-the-shelf electronic test equipment to reduce costs, shorten leadtimes, assure reliability, and simplify logistics, Report of the Task Force on Science Board,

Department of Defense, Washington (Feb. 1976).

Minutes of Automatic Test Equipment Conference and Workshop (April 1976) by Industry

Ad Hoc Automatic Test Equipment Project for the Navy, National Project for the Navy,

National Security Industrial Assn., Washington, DC, to be published late 1976.

Technical Manual - Calibration Technical Orders, Responsibilities and Calibration

Measurement Areas, TO 33K-1-100, U.S. Air Force (March 1972).

1975 Annual Statistical Report, Electrical World 183 , No. 6, 44-75 (March 1975).

A Summary of Program Emphasis for 1976, Electric Power Research Institute, Palo Alto,

CA (1976).

U.S. Industrial Outlook 1974 with projections to 1980, Department of Commerce,

385 pages (1974).

U.S. Markets Forecast 1977, Electronics, Vol. 50, No. 1, p. 90 (Jan. 6, 1977).

Houghton, S., Transfer of the Ki lowatthour, IEEE Trans, on Power Apparatus and Systems,

Vol. P94, No. 4, 1232 (Jul. /Aug. 1975).

A National Plan for Energy Research, Development and Demonstration: Creating Energy

Choices for the Future, ERDA 48, Vol. 2, Energy Research and Development Agency

(June 1975).

IEEE Power Engineering Society Proceedings of Conference on Research for the Power

Industry, IEEE, NY (1973).

Underground Power Transmission, Electric Research Council, NY (1971).

Electric Utilities Industry Research and Development Goals through the Year 2000,

Electric Research Council, NY (1971).

EPRI Transmission and Distribution Division Report, EPRI Journal, Vol. 3, 28 (April 1976)

EPRI Transmission and Distribution Division Report, EPRI Journal, Vol. 1, 40 (February

1976) . EPRI Transmission and Distribution Division Report, EPRI Journal, Vol. 2, 34 (March 1976)

Allen, R., Instrumentation: smaller and smarter, IEEE Spectrum, Vol. 13, No. 1, 68

(Jan 1976).

Eicke, W.G., Jr., and Auxier, L. M. , Regional Maintenance of the Volt Using NBS Volt

Transfer Techniques, IEEE Trans. Instrum. Meas., IM-23 , No. 4, 290-294 (Dec. 1974).

79
BIBLIOGRAPHY

1. Cochran, R. D., Measures for Progress, Nat. Bur. Stand. (U.S.) Misc. Publ . 275,

703 pages (1966).

2. Coombs, C. F. Jr., Editor, Basic Electronic Instriment Handbook (McGraw-Hill,

New York, NY, 1972).

3. Department of Commerce, Current Industrial Reports: Selected Instruments and Related

Products (U.S. Department of Commerce, Washington, DC, 28 pages, 1973).

4. Driscoll, R. L., Measurement of Current with a Pellat-type El ectrodynamometer, J. Res. NBS (U.S.), 60, No. 4, 287-296 (April 1958).

5. Driscoll, R. L. and Cutkosky, R. D., Measurement of Current with the National Bureau

of Standards Current Balance, J. Res. NBS (U.S.), 60, No. 4, 297-305 (April 1958).

6. Dun and Bradstreet, Million Dollar Directory, 1974, (New York, NY, 1974).

7. Harris, F. K., Electrical Measurements (John Wiley & Sons, New York, NY, 784 pages,

1952). _ ,.

8. Hermach, F. L. and Dziuba, R. F., Editors, Precision Measurement and Calibration - Electricity - Low Frequency, NBS (U.S.) Spec. Publ. 300, Vol. 3, 489 pages (Dec. 1968).

9. Lerner, W., Statistical Abstract of the U.S. - 1975, (Department of Commerce, Washington,

DC, 1028 pages, 1974).

10. Office of Management and Budget (U.S.), Standard Industrial Classification Manual,

1972 (U.S. Government Printing Office, 150 pages, 1972).

11. Olsen, P. T. and Williams, W. E., A More Accurate Determination of y' Through Im- proved Techniques, IEEE Trans. Instrum. Meas., IM-23 , No. 4, 302-305P(Dec. 1974).

12. Perry, John, The Story of Standards, (Funk & Wagnells, New York, NY, 271 pages, 1955).

13. Terman, F. E. and Pettit, J. M., Electronic Measurements, 2nd Edition (McGraw-Hill,

New York, NY 707 pages, 1952).

80
NBS-1 14A IREV. 7-73)

' U .S. DE PT . OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. ITHl.K ATION OR RI-PORT NO. NBSIR 75-935

2. Oov't Accession

No.

3. Recipient's Acces.sion No.

.4. TITl.l- ANl^i Sl H l l l I 1 Electricity Division Study of the National Measurement System

5. Publication Date

6. Performing Organization ( ode

7. AT I IIORiS) Norman B. Belecki, Bernadine L. Dunfee, and Oskars Petersons

8. Performing Organ Rmort No. NBSIR 75-935

9. l^KKKORMINC; ORC. AN' 1/ATlON NAMK ANP ADDRHSS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Proiect/Task/Work Unit No.

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Same as No. 9

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C ov e r e d Final

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16. .Ali,'^TRA("^ (A 200-v.oTd or less factual summary of most signilicant information. If document includes a significant

bibliography or literature survey, mention it here.)

The National Electrical Measurement System, by which all measurements of electrical quantities are made in the U.S., is reviewed. This overview, based on the

results of a four-year study, details the organizational structure of the system;

the technical aspects of realizing, maintaining, dissemination and using the units

for measurements; and the economic characteristics of its basic industry, the

instrumentation industry, and the system's user constituency. Documentary standards

and the organizations producing them are discussed, concluding with a survey of

presently adopted documents. Its two major components, the electronics subset and

the electric power subset, are defined, described, and contrasted. Major technical,

management, and logistics problems facing the system are delineated. An in-depth

view of the Electricity Division, which supplies the measurement base of the system,

is given. Finally, recommendations for technical and management action by NBS in a number of areas are given.

17. KHY VIOROS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) Calibrations; Di s s eml na t i on of units; Electrical measurements;

Electric power measurements; El ectrotechnol ogy ; Impact of measurements; Measurement

technology assessment; National Measurement System; Standards.

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