s
A -znclosure (1)

su Paper for the Distr

ibution Transformers Test Procedures Workshop February 10, 199
The Department is interested in receiving information and statements to help resolve the following issues: a. Adoption of nation al and international consensus standards in the test procedures for determining ene rgy eff iciency of distribution transformers. The Department is considering incorporating by reference six standards as the test procedures. The two primary test standards have been approved by the American National Standards fintitute (ANSI) and prepared by the Institute of Electrical and Electronics Engineers (IEEE): ANSI C57.12.90-1993, "IEEE Standards Test Code for Liquid -Immersed Distribution, Power and Regulating Transformers and IEEE Guide for Short Circuit Testing of Distribution and Power Transformers," and ANSI C57.12.91-1995, "IEEE Standard Test Code for Dry-Type Distribution and Power Transformers." Two other standards , ANSI C57.12.00-1993, "IEEE Standard General requirements for Liquid -Immersed Distribution , Power and Regulating Transformers," and ANSI C57.12.01-1989, "IEEE Standard General Requirements for Dry-Type Distribution and Power t ransformers, Including Those with Solid Cast and/or ResinEncapsulated Windings ," specify reference temperatures and joss tolerances for the transformers being tested and recommend preferred continuous power ratings for transformers . C57.12.00 also specifies accuracy tolerances of the measuring systems. The Department is also considering incorporating by reference .a guide prepared by the 

# , ( ·)!.;nelosure (1) b,ua Paper for the Distribution Tnmlformers Tat Procedures Workshop 011 February 10, 1991


### The Department is interested in receiving information and statements to help resolve the following issues:

. a. Adoptioll of national and international consensus standards in the tat procedures for**detemlJinin~** energy efficiency of distribution transformers. 

### The Department is co;'lsidering incoIpOrating by reference six 

### standards as the test procedures ..The two primary test**~dards** 

### have been approved by the American National Standards Institute (ANSI) and prepared by the Institute ofElectrical and Electronics Engineers (IEEE): ANSI CS7:12.90-1993, "IEEE Standards Test Code for Liquid-Immersed Distribution, Power and Regulating**T~ormers** 

### and IEEE Guide,for Short Circuit Testing ofDistribution and Power Transformers." and ANSI CS1.12.91-199S. "IEEE Standard Test Code for Dry-Type Distribution and Power Transformers." Two other standards, ANSI CS7.12.OO-1993, "IEEE Standard General**requirement~** 

### for Liquid -Immersed Distribution, Power and Regulating Transformers." and ANSI CS7.12.01-1989, 

### "IEEE Standard General Requirements for Dry-Type Distribution 

### and Power tfansformers, Including Those with 

### Solid Cast andlor ResinEncapsulated Wmdings," specify reference temperatures and Joss tolerances for the transformers being tested and recommend preferred continuous power ratings for tran,sformers. CS7.12.oo also specifies accuracy toieranees ofthe measuring systems. The Department is also**~~id~ring** 

### incorporating by reference.a guide**~repared** 

### by theNational Electrical Manufacturers Association (NEMA), 1-1996, "Guide for Determining

Efficiency for Distribution Transformers," with respect to ref erence temperatures and measures ofenergy tion. Finally, the Department is consid ering incorporating by refererice a single clause, 4.11.1 , in a standard prepared by the Interna tional Standards Organiza tion (ISO), ISO Standard 9001-1993 , "Quality Systems - Model for quality assurance in design, development, production, installation, and icing," regarding quality assurance of the test and measuring equipment. All of the above-m tion( ®d stagy. dards contain more information than that applicable to loss or efficiency testing. Hence, the Department only intends to incorporate by reference the applicable clauses in the proposed test procedures . Such requirements as reference temperatures, measures ofenergy consumption, measurement accur acy requirements are not fully consistent among the cited standards. DOE intends to use uniform test requirements in the proposed test procedures for both the liquid-immersed and dry-type transformers . Certain items, such as the sampling plan and the concept of a basic model , are not addressed by the referenced standards but are required in the DOE test procedures. The Department is aware of an effort by NEMA to produce a standard (TP 2, a companion to TP 1) on test procedures for efficiency determination of distr ibution transformers. DOE will examine this document for possible incorporation by reference in the proposed DOE test procedures, once the standard has been approved and finalized. Questions and Request for Comments (1) Are the six consensus standards appropriate for ref erencing as the DOE-required test practice? 4


### - 

# . National Electrical Manufacturers Association (NEMA). TP 1-1996,. "Guide for Determining Energy**Effi~ency** 

### for Distribution Transformers," with respect to reference temperatures and measures ofenergy cOnsumption. Finally, the Department is considering incorporating by reference a single clause, 4.11.1,_ 

### in a standard prepared by the International Standards Organization (ISO), ISO Standard 9001-1993, "Quality Systems
- Model for quality assurance in 

### design, development. production, installation, and servicing,"**regar~ing** 

### .quality assUrance ofthe test 

### and measuring equipment. All 

### ofthe above-mentionl%l stru.dards contain more information than that applicable to loss or efficiency testing.**Hen~,** 

### the Departl.nent only intends to incorporate by reference the applicable clauses in 

### the proposed test pl'l.lcedures. Such requirements as reference temperatures, measures ofenergy consumption,**m~surement** accuracy 

### requirements are not fully consistent among the cited standards. DOE intends to 

# use uniform test requirements in the proposed test procedures for both the liquid-immersed and dry-type 

### transformers. Certain items, such as the sampling plan and the concept ofa basic**mode~** 

### are not addressed by the referenced standards but are required in the DOE test procedures. The Department is aware ofan effort by NEMA to produce a standard (TP 2, a

. companion to TP 1) on test 

### procedures for efficiency determination ofdistnDution transformers.

DOE will 

### examine this document for possible incorporation by reference in the proposed DOE test procedures, once the standard has been approved and 

### finalized. Questions 

### and Regpest for Comments (I) 

### Are the six consensus standards appropriate for referencing as the DOE-required test**pra~ce'l**(2) Is the clause-by-clau se ref erencing of ANSI standards in draft 5 of "Test Procedure for on Transformers,' pp. 16.20, too detailed? Should such referencing 

### escribing dc resistance, no-l loss, and to loss measurements-and by alluding to the abbreviated by referencing only the appropriate sections in the two test codei-those
c clauses where qxceptions are made?
(3) Should additional relevant ds now in preparation and approval stages, such as IEEE PC57.123/D1.1 "Draft Guide for Transformer Loss Measurement" and NEMA -2 considered as additional or alternative references? Will such standards add to the knowledge base of the already existing consensus standards and enhance the user convenience? b. Burden imposed on industry, especially small manufacturers, by additional testing and data processing During the information gathering, and preparation of the draft, several items have caused concern and prompted debate during visits and presentations to interested parties. There was a general concern about additional and excessive burdens imposed on manufacturers as a result of new regulations, standards and testing requirements. Small manufacturers with limited test facilities were apprehensive about E's test requirements. The Department strives to base the proposed test procedures as much as possible on the existing standards . The actual tests and measurements in the NISI' draft test procedures are the 'The National Institute of Standards and Technology has developed a set of draft test procedures for distribution transformers which DOE is distributing to stakeholders in preparation for the public workshop. 

### (2) Is 

### the clause-by-clause**referencln~** 

### ofANSI standards in draft 

### 5 of "Test Procedure for**Distri~on** 

### Transformers;" PI'. 16
- 20, too detailed? Should mch referencing be abbreviated by 

### referencing only the 

### appropriate sections in 

### the two test code&-those describing dc resistance,**n~IQad** 

### loss, and lpad 

### loss measurements-and by alluding to the specific clauses where**~ceptions** 

### are made?

. (3) Should additional relevant standards now in 

### preparation and approval stages, such as IEEE peS7. 1231D

### 1.1 "Draft Guide for Trannormer Loss Measurement" and NEMA TP-2 be 

### considered as additional or alternative references? Will such standards add to the 

### knowledge base ofthe already existing consensus standards and enhance the user convenience?
b. Burden imposed on industry, especiaUy smaD manufadurers, by additional testing and data processing 

### During the infc;>nnation gathering and preparation ofthe draft, several items have**caus~** 

### concern and prompted debate during visits and presentations to interested parties. There was a general concern about additional and excessive burdens imposed on manufacturers as a result of new regulations, standards and 

### testing requirements. Small manufacturers with limited test facilities were apprehensive about DOE's test requirements. The Department strives to base the proposed test procedures as much as possible on the

. . 

### existing standards. The actual tests and 

### measurements**~** 

### the NIST1 draft 

### test procedures are the

. lThe National Institute ofStandards and Technology has 

### developed a set ofdraft test .' procedures for distnDution transfomiers whic:h DOE is distributing to stakeholders in 

### preparation

for the public workshop. .same as in the existing p ce. Ile draft test procedures include new requirements for sampling

and data Processing involving adjustment to now reference temperatures and calculation of efficiency from the loss data. DOE would ' e comments from manufacturer s about eir specific situations and anticipated difficulties, and suggestions to how problems can be solved and burdens minimized. Qusafians and It oast for Comments (1) Wha

t specific requirements in the NIS T draft test pr sire are causing concern about significant additional burden impo sed by testing requrements? Please cite difficulties anticipated.
c. Definition of "basic model" for distribution transformers. It is common for a single transformer manufacturer to make numerous models of transformers covered by EPCA. Often, several models are essentially the same transformer but with each model having some refinement that does not affect energy efficiency or ormance. A manufacturer may determine which models have electrical and mechanical characteristics that are essentially identical . Each such group of models may be categorized into a family , and only representative samples within each family, or "basic model ", would be tested. With regard to the residential appliance programs, 10 CFR 430.2 , the term " basic model" is defined as follows : "Basic model means all units of a given type of covered product (or class thereof) manufactured by one manufacturer and [with respect to dishwashers, for example] which do not have any differing physical and functional characteristics that affect energy consumption." DOE is considering a similar definition for transformers: "Basic model means all units of a • A 

### 'lame as in the exiSting**practice~** The 

### draft test 

### procedures include new requirements for sampling ad data 

### processing involvirig adjustment to 

### new reference temperatures and calculation of efficiency from the loss data.

. DOE would like comments from manufacturers about their specific situations and anticipated .difficulties,**an~** 

### suggeStions as to how problems can be 

### solved and burdens minimized. 

### "Questions 

### and Request 

### for Comments (l) 

### What specific requirements in the NIST draft test 

### pr:>eedut'e are causing concern about significant additional burden imposed 

### by testing requir"ments? Please cite difficulties anticipated.



### c. Definition of "basie model" for distribution transformers. 

### It is common for a single transformer manufacturer to make numerous models of transformers coveted by EPCA Often, several models are essentially the same transformer but

. with each model having some refinement that does not affect energy efficiency or performance. A



### manufacturet may determine which models have electrical and mechanical characteristics that are essentially id,entical. Each such group ofmodels may be categorized into a family, and only representative samples within each family, or "basic model", would be 

### tested. With regard to the 

### residential appliance programs, 10 CPR. 430.2, the term "basic model" ·is 

### defined as ,fonows: "Basic mOdel means all units 

### ofa given type 

### ofcovered product (or class "


### . ' 

### thereof) manufactured by**on~** 

### manufacturer and [with respect to dishwashers. for example] which do not have any differing physical and functional characteristics that 

# affect energy consumption." DOE is considering a similar definition for**transform~s:** 

### "Basic model means all units ofa®® Blven type of covered equipment (or class thereof) manufactured by, a single ' er and,



### ith raped to. distribution which have the same ratim have electrical eristics that are essentially identical, and do not have any differing physical or electrical 'stirs which affect 4 ion or efficiency." For the purpose of this definition, 68rating" would mean standard output power rating , such as one of those tabulated in NEMA TP 1, tables 4- 1 and 4®2. Questions and Request for Comments (1) In view of such a definition for a "basic model," do you anticipate significant difficulties in grouping your products into basic models? (2) For those manufacturers having only a few items per model, would it be possible to combine a number of models into families of basic models, e.g.,,grouping many actual production models of the same nominal kVA rating in one family of models? d. Sampling plan for units, to be test ed. The Code ofFederal Regulations (CFR), in 10 CFR Part 430 §430.23 outlines sampling plans for compliance testing. For example, under §430.23.(q)(1), "For each basic model of fluorescent lamp ballasts, as defined in p aragraph ( 14) of §430.2, a sample of sufficient size, no less than four, shall be tested to insure that ... (ii) Any represented value of the ballast efficiency ,factor or other measure of energy consumption of a basic model for which consumers would favor a higher value sno grea ter than the lower of(A) the mean of the sample or (B) the lower 99 percent confidence limit of the true mean divided by 0.99." • 4 

### given type 

### ofcovered**~pment** 

### (or class thereof) manufactured by a single manufacturer and)



### .

### ·wi~ respect 

### to. distribution transformers, which have the 

### same 

### rating, have 

### eleCtrical

·dw'aderistics that 

### are essentially identical, and do not have any differing physical or 

### electrical characieristics which affect energy 

### consUmption or efficiency." For the purpose ofthis definition, "rating" would mean standard· output power rating, such as one ofthose tabulated, in NEMA TP 1, 

### tables 4 - 1 

### and 4 - 2. 

### Questions 

### and ReQuest. for Comments (1) In 

### view ofsuch a definition for a "basic**mode~** tI 

### do you**anticipat~** 

### significant difficulties in 

### grouping your products into basic models? (2) For those manufacturers having only a few items per 

### model, would it be 

### possible to combine a number ofmodels into families ofbasic models, e.g., grouping many actual production models ofthe same nominal kVA rating in 

### one family ofmodels?
d.**Sa~piing** 

### plan for units.to be 

### tested. The Code ofFederal Regulations (CFR). in 10 CFR Part 430 §430.23 outlines. sampling plans for compliance testing. For**~ample.** 

### under §43().23.(q)(1). "For each basic model 

## , oftluorescent lamp ballasts. as defined in 

### paragraph (14) of §430.2. a sample ofsufficient size, no

. less than four. shall be 

### tested to insure 

### ihat ... (li) 

### Any represented value ofthe ballast efficiency**~or** 

### or other measure ofenergy consumption ofa basic model for which consumers would

&vor a higher value shall be 

### no greater than the lower of(A) the mean ofthe sample or (B) 

### the

. lower 99 percent confidence limit ofthe true mean, divided by 0.99."

. .The sampling for enf orcement testing is pr

ovided in 10 CFR P 430 §430.70, ip ' plan is f a determination of co 

### applicable standard.
of distribution transf

ormers : on the sta

tisti cal t-test yiel ding 97.5 percent probability liance when the true mean efficiency is equal to the
this time the Department is considering one of two sampling plans for compliance 1) TIM plan in §430.23, using the lower 95 percent confidence limit, but without specifying the minimum num ber ofunits in the sample (A minimum of two units is implicitly required to estimate the confidence limit.) The "IC" factor, b ased on the six percent lots tolerance specified in ANSI C57. 12.00 and C57 . 12.01, is selected to be 0.999. 2) A modifi ed version of the proposed sampling plan for enforcement testing of motors as outlined in 61 60474
- 60475, Appendix B to Subpart 'G.of Part 431, "Sampling Plan for Enforcement Testing," is considered for compliance testing of distribution transformers. The considered modification consists of replacing the factor (120 - 0.2 SFE)/SFE(20 - 0.2 SFE) in equation (5) by the new factor (106 - 0.06 SFE)/SFE(6
- 0.06 SFE). This plan yields a 90 percent probability of obtaining a determination of compliance when the true mean is equal to the standard. For the enforcement testing of tformers the Department is considering a plan similar to 2) above but changing the probability of det ermination of the compliance from the 10th

-percentile to the 2 . 5th percentile. Qu estions and R equest for Comments (1) Please provide comments on the two sampling plans DOE is considering for compliance 

## .. 

# . • "'.1' ••



### . The 

### san;tpling 

### plan for enforcement testing is provided in 10 CFR Part 430 §430.70, 'Appendix 

### B. This. sampling plan is 

### baSed on the 

### statistical t-test yielding 97.5**~cent** 

### probability ofobtaining 

### a determination ofcompliance when the 

### trUe mean efficiency is equal to the



### . appliCable standard.



### . Ai this time the 

### Department is considering one oftwo sampling plans for compliance**t~** 

### ofdistribution transformers:

1) The 

### plan described in 1430.23. using the lower 95 percent confidence limit. but without specifying the minimum number ofunits in the sample (A minimum oftwo units is 

### implicitly required to estimate the confidence limit.) The "K" 

### factor, bued on the six percent lOGS 

### tolerance specified in ANSI C57.12.00 and C57.12.01. is 

### selected to be 0.999.

.2) A modified version ofthe proposed sampling plan for enforcement testing ofmotars as outlined in 

### 61 F.R 

### 60474
- 60475, Appendix B to Subpart G.ofPart 431, "Sampling Plan for

. , . 

### Enforcement Testing," is considered for compliance testing ofdistnbution transformers. The

. considered modification consists ofreptaeing the factor (120**~** 

### 0.2 SFE)/SFE(20
- 0.2 SFE) in

equation (5) by 

### the new factor (106
- 0.06 SFE)lSFE(6
- 0.06 SFE). This 

### plan yields a 90 percent

. .



### . probability ofobtaining a determination ofcompliance when the true mean is equal to the

standard. For the enforcement testing oftransformers the Department is considering a plan similar to 2) above but changing the probability ofdeiermination ofthe 

### compliance from the 10th .percentile to the 2.Sth percentile. Questions and Request 

### for Comments (1) Please provide comments on the two sampling plans DOE is considering for compliance

. ' 

### .(2) Please describe other appr oaches you believe DOE should consider.
Selection ofa measure of energy consumption for distribution transformers. DOE considers efficiency as the preferable measure of energy consumption . The industry ce, as required by the cited ANSI standards, has been to mand report transformer losses. DOE believes tha

t for ener gy conservation purposes =111 ciency is a better measure as it presents a unified and normalized measure allowing manufacturing trade-offs between the two types oflosses . -(Transformer losses would still be measured to determine efficiency.) The Department would like to obtain comments on this measure of energy consumption and the practicality of its use for the DOE test procedures. Questions and BQ]jj9 for Comments (1) Are there any strong reasons why efficiency should not be used? (2) Should other measures of energy consumption be considered : e.g., loss, power normalized relative to output kVA, either on per unit basis or percentage basis? (3), Is reporting ofefficiency and losses at reduced loading levels appropriate for an energy conservation standard? 

### 10 . fSelection of reference temperatures the reference temperatur es in consensus standards lack unifo rmity. 

### testing. 

### (2) Please descrlDe other approaches you believe DOE should consider.

eo Selection of" measure ofeneray consumption for distribution transformers. DOE**co~ders'**

### efficiency 

### as the 

### preferable measure ofenergy consumption. The industry 

### practice, as required by the cited ANSI standards, bas 

### been to**m~e** 

# and**~eport** 

### transformer losses. DOE 

### believes that for energy conservation purposes efficiency is 

### a better measure 

### as it presents a unified and normalized measure allowing· manufacturing trade-offs between the two types oflosses. '(Transformerlosses would 

## still be measured to determine efficiency.) The Department would like to'obtain comments on this measure ofenergy consumption and the practicality ofits use for the DOE test procedures. Questions 

### and Request for 

### Comments (1) Are there any strong reasons why efficiency should not be used? (2) Should other measures ofenergy consumption be considered: e.g., loss. power normalized relative to output kVA, 

### either on per unit basis or percentage basis? (3). Is 

### reporting ofefficiency and losses. at .reduced loading levels appropriate for an energy conservation standard?
f. Selection ofreference temperatures - the reference**temper~tures** 

### in consensus**standar~s** 

### lack uniformity.C57.12.00 specifies reference temperatures for liquid immersed o : 20°C for

no-load losses 85°C for load lo on 20°C dent temperature and 65 °C temperature rise at the rated full load. 057. 12.01 s es five, reference temperatures for load losses load: 80, , 135, 150, and 170°C based on 20°C ambient temperature and temperature rises of five insulation classes; no reference temperature is specified for no-load losses. I specifies reference temperatures of 20°C for no-load losses of both types of tranArmers, 85 °C for load losses of liquid- immersed transformers, and 75 °C for load-losses of all dry-type transformers. 1 specifies efficiency at less than the rated full load-S0 % of the rated load for all liquid- immersed and medium voltage dry-type transformers, 35% of the rated load for the low voltage dry-type transformers. NIST calculated the temperature rises for reduced loading per TP 1. After examination, these data suggest that 75 °C represents an approximate average of the ten conditions involving two loading levels and five temperature rises. A similar calculation was ormed for the liquid

-immersed transformers, yielding a temperature rise of 35 °C and consequently a " new reference temperature " of 55°C. DOE is considering using 20°C as the reference temperature for no-load losses of alltransformers, 75°C for load losses of dry type transformers, and 55°C for load losses of liquidimmersed transformers, should the future DOE energy conservation standard require loading levels as in 1 . DOE 'eves these ref erence temperatures would make representations of test data for both types of transformers more consistent.
estions and Request for Com is Please provide comments , especially if there are in your view strong reasons for or against the following modifications in reference temperatures from the values established in ANSI 

### '0 .'
,CS7.12.00 specifies reference temperatUres for liquid immersed transformers: 20 0 

### e for no-load losses and 8S·C 

### fur load losses, 

### based on 200 

### e ambient'temperature and 6Soe

. . 

### temperature riSe at 

### the rated fiillload. CS7.12.01 specjfies five,**r~ference** 

### temperatures for load

- ' ' I 

### losses at the 

### rated full 

### load: 80, 100, 13S, lS0, 

### and 1700 

### e based 

### on loDe ambient temperature and**tempera~e** 

### rises offive insulation classes; no rd'erence temperature is specified for no-load losses. TP 1 

### specifies reference temperatures of20°C for no-lOad lQsses ofboth types of transformers, 8SoC for load losses ofliquid-immersed transformers, and 'SoC for load-losses of 

## an dry-type transformers. TP 1 specifies efficiency at less than the rated full load-SO % 

### ofthe

, 

### rated load for all liquid-immersed transformers and medium voltage dry-type transformers, 3S% 

### ofthe rated load for the low voltage dry-type 'transformers. NIST calculated the temperature rises for reduced loading per TP 1. 

### After examination, these data 

### suggest that 7SoC represents an approximate average ofthe ten conditions involving two loading levels and five temperature rises. A similar calculation 

### was performed for the 

### liquid-immersed transformers, yielding a temperature rise of3SoC and**conseque~tly** 

### a 

# "new reference temperature" ofSSoC. DOE is 

### considering using lOoe as the reference temperature for**no-loa~** 

### losses ofall transformers, 1SoC for load losses ofdry-type**transform~rs.** 

### and SSoC for load losses ofliquid-**~ersed** 

### transformers. should the future 

### DOE energy conservation standard require loading

, , 

### levels as in 

### TP 1. DOE believes these reference teniperatures would make representations oftest data for both types 

### oftransformers more consistent.
Ouestions and**~eguest** 

### for Comments Please provide**comments.especiallyif~ere** 

### are in your view strong reasons for ()r against the following modifications in**ref~ence** 

### temperatUres from the values established in ANSIStandards C57.12. 00 and C57.12.01:



### ( 1) reference temperature of 20°C for no-load losses of dry-type transformers (also

by TP 1).
(2) Specifying a single reference temperature of 75°C for load losses of dry-type transformers ha ving all five insulation ses . two loading levels (also required by 1), in effect 10 temperature rise conditions are approximated by one. Calculation of the actual temperature rises indi tes that for four conditions the reference temperature rise is underestimated (the actual temperature will be higher than 75 °C), for five it is overestimated, and for one the calculated temperature is 75°C. (3). Specifiling a ref

erence temperature of55°C for load losses of liquid-immersed transformers at 50% load.
g. Requirement for applying corrections to measurement data of both liquidimmersed and dry-type types of tsformers. C57.12. 90 requires corrections for the phase angle error of m easuring instruments when measuring load lo sses ha

ving a low power factor. An algorithm is provided in C57.12.90 to calculate this correction and a table summarizing conditions under which this correction should be applied or can be neglected. This standard also specifies corrections for the no-load loss data if measurements are performed otherthan the specified reference temperature of 200C. Again, an algorithm is provided . Such corrections are not required in C57. 12.91 for dry-type

I T o· 

### Standards

### CS7:12.00~ CS7.12.oi:

I (l) 

### Speclfying reference temperature of20°C for no-load losses ofdry-type transformers (also 

### required by TP 1). 

### (2) SpecifYing a single reference temperature of7SoC for load**l~sses** 

### ofdry-type transformers baving all 

### five insulation clusesand two loading levels**(aI~** 

### required by 

## TP 1), in effect 

### 10 temperature rise conditions are approximated by one. Calculation ofthe actual temperature rises mdicates**~t** 

### for four conditions the reference temperature rise is underestimated (the actual temperature will 

### be higher than 7S0C), for five it is 

### overestimated, and for one the calculated temperature is 7SoC. (3) Specifying a reference temperature ofSSoC for load losses ofliquid-immersed transformers at 

### SOOIO load.


### I. Requirement for applying corrections to measurement data ofboth liquidimmersed and dry-type types oftransformers•. 

### C57 .12.90 requires corrections**fo~** 

### the phase**an~e** 

### error ofmeasuring instruments when

·measuring load losses having 

### a low' power factor. An 

### algontbm is provided in CS7.l2.90 to Calculate this correction and a table summarizing Conditions under which this correction should be applied or can be neglected. This standard also specifies corrections (or the no-load loss data if 

### measurements are performed at 

### other than 

### the specified reference temperature of20°C. Again, 

### an algorithm is provided. Such corrections are not tequired in CS7.12.91 for dry-type .brmen DOE is considering applying corrections to both

estions It uest for r o

.. . corrections, if required, to memrement data of dry.

is already done for liquid immersed transformers? Requirement for quality assumnce in testing. C57.12.00 provides a table of u.ncertainty'limits of vari ous measurements required in loss or efficiency determination. DOE believes that this table should be applicable to dry-type

T o ensure compliance with the requirements in this table, DOE is considering including ' for guidance the following ' partial clause (4.11.1) from ISO. d 9001-1993: " e supplier shall establish and maintain documented procedures to control, calibrate and maintain inspection, measuring and test equipment (including test software) used by the supplier to demonstrate the conformance of product to the specified requirements. Inspection, measuring and test equipment shall be u sed in a manner which ensures that measurement uncertainty is known and is consistent with the required measurement capability." Questions and Request for Comments (1) Are there concerns about applying measurement accuracy requirements to dry-type

o is now done for liquid
-immersed transformers, and about inclusion for guidance of a clause from ISO 9001 -1993 on measurement quality assurance procedures? 

# ..

, '**transformers~** 

### DOE is 

### considering applying corrections to both 

### tnmsformer types.'

, 

### Ouestions apd 

### ReQuest for 

### Comments (I) 

### Are·there concerns 

# .oout applyfug corrections. ifreqwred, to**~rement** 

### data ofdrytype 

### transformers as is already 

### done, for liquid 

### immersed transformers?
Ia. Requirement for quality u.urance in testing. 

### CS7.12.00 provides a table of

### uncertainty' limits ofvarious mtuurements required in loss or efficiency determination.' DOE believes that this table should be applicable to dry-type 

### transformers. To ensure compliance with the requirements in 

### this table, DOE is considering including for guidancetbe following partial clause (4.11.1),from ISO standard 9001-1993:

. , 

### "The supplier shaII.establish and maintain 

### documented procedures to controt calibrate and 

### .maintaiIl inspection,.measuring and test equipment (mcluding test software) used by the supplier to demonstrate the conformance ofproduct to the**speci~ed** 

### requirements. Inspection, measuring and test equipment 

### shall be 

### used in a 

### manner which 

### ensures that .

,measurement 

### uncertainty is known and is consistent with the required measurement 

### capability." .

. Questions and Request for**C~ts** 

### .(1) Are there conceins about applying measurement 

### accuricy requirements to dry-type transformers as is DOW 

### done for liquid-immersed transformers, and about inclusion for guidance ofa clause from ISO 

## 900 1 ': 1993 on measuremeni

### q~tY assurance procedures?

. " 

### . .427 P02 JAN 12 '• 98 16:00 Nation al l Stand ards a Ta , b G a i t h u r g , Maryland 9 1.

Telephone; (301)975-2431 fra*Na.! (301)948-5796 Mall: Room B344, Building 220 January 12, 1998 Ms. Kathi Epping Program Manager Office of Codes and Standards, EE 43 Department of Energy 1000 Independence Ave. S.W. Washington, D.C. 20585 Dear Ms. Epping: Enclosed is a copy of a report "Energy Conservation Program for Consumer. Products; Test Procedure for Distribution Transformers," draft 5, prepared by the Electricity Division, National Institute of Standards and Technology (NIST) for inclusion in the Department ' s notice of proposed rulemaking for test procedures. This draft is submitted to DOE for distribution to prospective attendees of the Department's workshop on distribution transformer test procedures, scheduled for February 10, 1998, and to other interested parties to stimulate discussion at the workshop and submission of peer review comments. The material including recommendations in the submitted draft is preliminary and. may differ from that in the final report. Since the draft report is of a preliminary nature and has not received full review byNIST, it may, n.ot be cited and referenced for the purpose other than those stated in this letter.
arues K. Oltboff;.Leader Electrical Systems Group' Electricity Division cc: J. Hill Enclosure 427 P02 . JAN 12 '·98 1/?:00 UlamED STATEB DEPAMMENT 

### oF COMMERCII! N.Ukmal**.~** of Btandllllrds .nd Technology .

.**~ithenburg.** Maryland 2QB99aJO'I· .
January**12~** 1998 

## Ms.**~tbi** Epping Program Manager. . " . Office ofCodes and Standatds, EE 43

Department 

## ofEnergy· 1000 Independence Ave. S.W..**Washington~** D.C. 20585 Dear 

### Ms. Epping: .. Telaphon.; (lOI )11'15-2431 pal( Wo.: ·(SOI)!I4S.S7!16 1'4&11: ltpom**B3"'~.** BlIlJdins**~:ZO**

Enclosed is a copy Qf a report "Energy Conservation Program for Consumer Products; Test procedure for Distrihution Transformers." draft 

### 5, prepared 

### by the Electricity Divisi6n, National InStit)J.te ofStandards and Technology (NIST) for inclusion in the Department'snotice of" . proposed rulemaking for test proccdw:cs. This ¢aft is submitted to DOE'fo! distribution to prospective attendees**ofth~** Department's workshop on distribution transformer test procedures, scheduled for February 10, 1998, arid to other interested parties to stimulate discussion at the 'Workshop and 'submission ofpeer review comments. The material including recommendations in the**submitt~** draft is 

### preliminary. arid may differ from that 

### in the .tiDal report. . . .. Since the draft report is of a preliminary nature and has not received full revievv by.NIST. it may· . not be cited and referenced. for the purpose other 

# than: those stated in this letter. . 

### .• SinoerOly,t!

### ~.

# ~lIbOfl;Leadei ..

Electrical Systems Group'! Electricity Di,vision '

. cc: J. 

### :fiill

, Enclosure , .



# NISiINIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

**************************************************************************** Energy Conservation Program for Consumer Products; Test Procedure for Distribution Transformers Draft 5 January 12, 1998 Preamble (Note: introductory administrative material teen delete 'this draft) Discussion The Department of Energy proposes to adopt tes rocedure for distribution transformers. This test procedure would apply to those pr s covered section 325(g)(5) of the Act ( The Energy Policy and Conservation Act (SPCA)
1. Test Procedure The Departme' s consi 'ng incorporate by reference six standards, as referenced in section 323(b)(5) of the , as a est procedure in Appendix S to Subpart B of 10 CFR part 430. Four of these, constitute the primary references, are national standards prepared by the Institute of Electrical and Electronics Engineers (IEEE) and approved by the American NationalStandards Institute (ANSI): ANSI C57.12.90-1993, "IEEE Standards Test Code for LiquidImmersed Distribution, Power and Regulating Transformers and IEEE Guide for Short Circuit Testing of Distribution and Power Transformers," ANSI C57.12.91-1995, "IEEE Standard Test Code for Dry-Type Distribution. and Power Transformers," ANSI C57.12.00-1993, "IEEE Standard General requirements for Liquid-Immersed Distribution, Power and Regulating i NIST DRAFT OF NOPR FOR DISTRmUTION TRANSFORMER TEST PROCEDURE 

### ****************************************************************************

Energy Conservation Program for Consumer Products; Test Procedure for Distribution Transformers . Draft 5 January 12, 1998 Preamble (Note: introductory administrative material . I Discussion The Department ofEnergy proposes to adopt te cedure for distribution transformers.

. This test procedure would apply, to those pr section 325(g)(5) ofthe Act (The

Energy Policy and Conservation Act (EPCA)


### 1. Test Procedure
The Departme· incorporate by reference six standards, as referenced in section 323(b)(5) of the as a est procedure in Appendix S to Subpart B of 10 CFR part the primary references, are national standards prepared by the Institute ofElectrical and Electronics Engineers (IEEE) and approved by the American National Standards Institute**(ANSI)~** ANSI C57.12.90-1993, "IEEE Standards Test Code for LiquidImmersed Distribution, Power and Regulating Transformers and IEEE Guide for Short Circuit Testing ofDistribution and Power Transformers," ANSI C57.12.91-1995, "IEEE Standard Test Code fot Dry-Type Distribution and Power Transformers," ANSI C57.12.00-1993, "IEEE Standard General requirements for Liquid-Immersed'**Distributi~n, ~ower**  and RegulatingNIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

**************************************************************************** Transformers ," ANSI C57. 12.01-1989 , " IEEE Standard General Requirements for Dry-Type Distribution and Power Transformers , Including Those with Solid Cast and /or ResinEncapsulated Windings ." The Department also considers incorporating by reference a guide prepared by the National Electrical Manufacturers Association TP 1-1996, " Guide for Determining Energy Efficiency for Distribution Transformers ,' i t spect to reference temperatures and measures of energy consumption . Fina he Depart t considers incorporating by reference a single clause , 4.11.1, in tan rd prepared by the International Standards Organization (ISO), ISO Standard 9001
- 1993, Quality Systems - Model for quality assurance in design , development, productio tallation ,servicing," regarding quality assurance of the test and measuring equipmen All previously mentioned st ds cons ore information than that applicable to loss or efficiency testing . Hence, o e a abl causes are incorporated by reference in the draft DOE test procedure . Any subseque endment to these standards by the standard
- setting organizations (ANSI, E, I ) will not affect the DOE test procedure, which can be. amended only by DOE. test ocedure will provide results suitable for determining whether the products comply with the dard levels which may be established by the Act. Additionally, the Department specifies in the proposed test procedure the following requirements which either are not found in the cited references or may differ among these references , but are needed to comply with the Act: ( 1) using transformer efficiency at specified loading levels as the preferred measure of energy consumptiod ; (2) using the same reference temperature of 20 ° C for reporting the no
-load losses of liquid
-immersed and dry-type transformers ; (3) if the efficiency is selected at lower than the rated loading , using the reference 2 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** Transformers," ANSI CS7.12.01-1989, "IEEE Standard General Requirements for Dry-Type Distribution and Power Transformers, Including Those with Solid Cast and/or ResinEncapsulated Windings." The Department also considers incorporating by reference a guide prepared by the National Electrical Manufacturers Association , TP 1-1996, "Guide for Determining Energy Efficiency for Distribution Transformers,' temperatures and measures ofenergy consumption. Fina t considers incorporating by reference a single clause, 4.11.1, in d prepared by the International Standards Organization (ISO), ISO Standard 9001-1993, assurance in design, development, productio . servicing," regarding quality assurance ofthe test and measuring equipmen

, All previously mentioned st ore iriformation than that applicable to loss or efficiency testing. Hence, 0 organizations (ANSI, amended only by DOE. the products comply with the causes are inporporated by reference in the draft endment to these standards by the**stand~d-setting** ) will not affect the DOE test proc,edure, which can**b~.** ocedure will provide results suitable for determining whether dard levels which may be established by the Act. Additionally, the Department specifies in the proposed test procedure the following requirements which either are not found in the cited references or may 'differ among these references, but are needed to comply with the Act: (1) using transformer efficiency at specified loading levels as the preferred measure 

### ofenergy consumptiorl; ,(2) using the same reference temperature of20°C for reporting the no-load losses ofliquid-immersed and dry-type transformers; (3) ifthe efficiency is selected at lower than the rated loading, using the reference 2NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

temperature for load losses that approximates the temperature rise at new loading conditions (as opposed to using temperature rises as in ANSI standards for rated nameplate loading); for example, if loading levels such as those in NENIA TP 1 are selected, reporting of efficiency of liquid-immersed transformer at 50% of the rated load and the refe temperature 55'C for load losses; reporting of efficiency of dry-type transformers ra \ ** d fo . edium voltages, 1201 volts and above, at 50% of the rated load and the reference to ature of 7 for load losses; reporting of efficiency of dry-type transformers rated r 1 voltages, up to 1200 volts, at 35% of the rated load and the reference temperature of 75 ° C load losses; (4) correcting the measured load loss data of dry-type transfo for phase le errors in the measuring equipment as required in ANSI standards for significant relative to required meas data of dry-type transformers t liquid-immersed transformers , if such accuracy; ( 6) measurin sed transformers, if such errors are pnt acc ; (5) correcting the measured no-load loss erature of 20°C as required in ANSI standards for correction is significant relative to required measurement t e transformers to the same accuracy as specified for The test procedure inv es the measurement of electric power consumed by the transformer in the form of no-load and load losses, as well as'determination of certain other quantities . needed to establish the test conditions : temperature of the windings and the core; current, voltage, frequency and waveform of voltage, and direct current resistance of the windings. Certain quality assurance procedures necessary to ensure reliable test data'are available. in ISO. 9001- 1993 and are recommended as examples in this DOE test procedure. In summary, the considered DOE test procedure retains the same measurements of losses , NISI DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE*************************************************************************~******

temperature for load losses that approximates the temperature rise at new loading conditions (as opposed to using temperature rises as in ANSI standards for rated nameplate loading); for example, ifloading levels such as those in NEMA TP 1 are selected, reporting ofefficiency of

, 

### . liquid-immersed transformer at 50% ofthe rated load and the refl temperature 55°C for load losses; reporting ofefficiency ofdry-type transformers ra and above, at 50% ofthe**rat~dload** and the reference te for load losses; reporting ofefficiency ofdry-type transformers rate voltages, up to 1200 volts, at 35% ofthe rated load and the reference temperature of75°C ad losses; (4) correcting the measured load loss data ofdry-type transfo e errors in the measuring equipment as required in ANSI standards for I sed transformers, if such errors are sigQificant relative to required meas ; (5) correcting the measured no-load loss data ofdry-type transformers t erature of20 cC as required in ANSI standards for liquid-immersed transformers" if sucH orrection is significant relative to required measurement**~ccuracy;** (6) measuri e transformers to the same accuracy as specified for liquid-immersed transfo es the 'measurement ofelectric power consumed by the transformer in the form ofno-load and load losses, as well as'determination of certain other quantities ,needed to establish the test conditions: temperature ofthe windings and the core;

- current, voltage, frequency and waveform ofvoltage, and direct current resistance ofthe

windings. Certain quality assurance procedures necessary to ensure reliable test data 'are available in ISO 9001- 1993 and ar:e recommended as examples in this**DO~** test procedure. In summary, the considered DOE test procedure retains the same measurements oflosses 3 'NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

***********************************k*********** *************** ************** as specified in the current versions of the previously cited ANSI standards, but requires some harmonization of requirements for the two types of transformers; additional computation is required to convert the data to reference temperatures consistent with reporting of efficiency at lower than the rated loading. 2. Reference Conditions DOE is considering to establish certain reference nditions for reporting the test results. For the purpose of this DOE test procedure iency of li id-immersed transformers is reported at 50% of the rated load and the refe n e rature of 20°C for no-load losses and 55°C for load losses ; efficiency of and above, is reported 'at 50% load losses and 75°C for load losses; up to 1200 volts, is re no-load losses and 75°C computation should be adjust ers operated at medium voltages, 1201 volts and the reference temperature of '20°C for nociency of dry-type transformers operated at low voltages, e rated load and the reference temperature of 20°C for sses' . The measured no-load and load losses used in efficiency to the stated reference conditions, if such adjustments are significant relative to the required measurement accuracy. Under the current industrial practice, the load losses of liquid-immersed transformers are reported at the rated load and the reference temperature of 85°C, as specified by ANSI 'Establishing of specific, loading levels belongs to the energy conservation standard, but correction of measurement data to new reference conditions is a part of the test procedure. The loading levels of the NEMA. TP i are used here . only as examples. NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** as specified in the current versions ofthe previously cited ANSI standards, but requires some harmonization ofrequirements for the two types oftransfonners; additional computiltion is required to convert the data to reference temperatures consistent with reporting ofefficiency at, lower than the rated loading.

, 2. 

### Reference Conditions
DOE is considering to establish certain reference ·tions for reporting the test results. For the purpose ofthis DOE test procedure Id-immersed transformers is reported at 50% ofthe rated load and the refe rature of20°C for no-load losses and 55°C for load losses; efficiency of ers operated at medium voltages, 1201 volts and above, is reported at 50% ad and the reference temperature of'20°C for noload losses and 75°C for load losses; iency ofdry-type transformers operated at low voltages, up to 1200 volts, is re e rated load and the reference temperature of20°(: for no-load losses and 75°C sses 1 • The measured no-load and load losses used in efficiency computation should be adjust to the stated reference conditions, ifsuch adjustments are significant relative to the, required measurement accuracy. Under the current industrial practice, the load losses ofliquid-immersed transformers are

.reported at the rated load and the reference temperature, of 85°C, as specified by ANSI lEstablishing of specific, loading levels belongs to the energy conservation standard, but correction ofmeasurement data to new reference conditions is a part ofthe test procedure. The, loading levels ofthe NEMA TP.l are used here,only as examples.

4'NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

**************************************************************************** 057.12.00. This reference temperature is based on ambient temperature of 20°C and the temperature rise of 65°C. The load losses of dry-type transformers are reported at the rated load and, based on the insulation system used, at one of five specified temperature rises in addition to ambient temperature of 20°C, as specified by ANSI 057.12.01. T ultant reference temperatures are: 80, 100, 135, 150, and 170°C., ANSI stand s .12.90 and C57.12.91 provide an identical algorithm for converting the measur ad loss va to specified reference temperatures. For no-load losses of liquid-immersed transforms ANSI 057.12. 00 specifies the reference temperature of 20°C, thus approxi ftg ambient nditions . Additionally, ANSI 057.12.90 provides an algorithm for converti temperature to that at the reference erature `.No reference temperature is specified for the no-load losses of the dry-type t The NEMA Guide TP 1, 199 ecommends minimum efficiencies and the following reference conditions fo istribut tra formers: for liquid- immersed transformers the reference loading is 50% of rated to and t reference temperatures are 20°C and 85°C for no-load and load losses , respectively; fort medium-voltage dry-type transformers, the reference loading is 50% of the rated load and the reference temperatures are 20°C for no-load losses and 75°C for load losses ; for the low-voltage dry-type transformers, the reference loading is 35% of the rated load and the reference temperatures are 20°C for no-load losses and 75°C for load losses. The previous examples illustrate considerable diversity in the reference conditions as specified in the existing consensus standards . To enhance uniformity in requirements and facilitate comparison of products using liquid-immersed and dry-type insulations , the Department is NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

###  .** ************* ••****************************************************** CS7.12.00. This reference temperature is based on ambient temperature of20°C and the temperature rise of 65°c. The load losses of dry-type transfonners are reported at the rated load and, based on the insulation system used, at one offive specified temperature rises in addition to ambient temperature of20°C, as specified by ANSI CS7.12.01. temperatures are: 80, 100, 13S, ISO, and 170°C.. ANSI stand provide an identical algorithm for converting the measur to specified reference temperatures. For no-load losses ofliquid-immersed transfonn SI CS7.12.00 specifies the reference temperature of20°C, thus appro' nditions. Additionally, ANSI CS7.12.90 provides an algorithm for converti loss value measured at another temperature to that at the reference reference temperature is specified for the no-load losses ofthe dry-type t 

# . . commends minimum efficiencies and the following reference conditions fc fonners: for liquid-immersed transfonners the reference loading is SO% ofrated 1 reference temperatures are 20°C and 8SoC for no-load and load losses, respectively; for t medium-voltage dry-type transformers, the reference**l~ading** is SO% ofthe rated load and the reference temperatures are 20°C for no-load losses and 75°C for

. load losses; ror the low-voltage dry-type transformers, the reference loading is 35% ofthe rated

load and the reference temperatures are 20°C for no-load losses and 75°C for load losses. The previous examples illustrate considerable diversity in the reference conditions as' specified in the existing consensus standards. To enhance unifonnity in requirements and facilitate comparison ofproducts using liquid-immersed and dry-type insulations, the Department is 5KIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

considering 20°C as the reference temperature for no
-load losses of both transformer types, 55°C as the reference temperatures for load losses of liquid-immersed. transformers operating at 50% of the rated load, and 75°C as the reference temperature for load losses of dry-type transformers operated at 50% and 35% of the rated load. Three considerations influenced the selection of these ere a temperatures : to obtain' uniformity in reference conditions, to have the reference itions that reflect the actual operating conditions , to maintain consistency with th ra es of the current consensus standards as much as possible . Satisfying all three state nditions was not practical or even possible , because of the previously mention ersity in th xisting practice. The proposed reference temperature for no -load losses of bo es ransformers is 20°C which is consistent with C57.12. 00 and TP 1, but not O 57.12. hich does not specify the reference temperature for no-load losses ry- an formers. This . reference temperature is close to the ambient temperature, readily avai le for loss measurement when the transformer is cold, but does not represent ope ing con ion However, the changes in the core losses due to temperature are small , q'u d as x 10' per unit per °C,' and will have small effect on the resultant calculated efficiency., If the measure of transformer energy consumption in a potential future energy conservation standard is efficiency at less than full-rated or nameplate loading , it is proper to adjust the reference temperature for load losses as done in TP-1 for dry-type transformers. It is proposed that in the DOE test procedure the reference temperature be lowered also for the load losses of liquid-immersed transformers from 85 °C to 55°C to better approximate the conditions of the actual use and extend the same approach to both types of transformers . The conversion of 6 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** considering 20°C as the reference temperature for no-load losses ofboth transformer types, 55°C as the reference temperaiures for load losses ofliquid-immersed. transformers operating at 50% of the rated load, and 75°C as the reference temperature for load losses ofdry-type transformers operated at 50% and 35% ofthe rated load. Three considerations influenced the selection ofthese to obtain' uniformity in reference conditions, to have the reference reflect the actual operating conditions, to maintain consistency with th ,s ofthe current consensus standards as much as possible. Satisfying all three state ditions was not practical or even possible, because ofthe previously mention xisting practice. The proposed reference temperature for no-load losses ofbo ransformers is 20°C which is consistent with C57.12.00 and TP I, but not hich does not specify the reference temperature for no-load losses ormers. This reference temperature is close to the ambient temperature, readily avat e for loss measurement when the transfornier is cold, but does not represent op However, the changes in the core losses due to temperature are small, qu" x 10-4 per unit per °C,' and will have small effect on the resultant calculated efficiency**Ift~e** measure oftransformer energy consumption in a potential future energy

, , conservation standard is efficiency at less than full-rated or nameplate loading, it is proper to

. adjust the reference temperature ror load losses as done in TP-l for dry-type transformers. It is '

proposed that in the DOE test**proced~re** the reference temperature be lowered also for the load 'losses ofliquid-immersed transformers from 85°C to 55°C to better approximate the conditions of the actual use and extend the same ap'proach to both types oftransformers. The coilVersion of ' 6NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

load losses to a different reference temperature is a computational operation using a well established algorithm published in ANSI C57,12.90 and ANSI C57.12.91. For load losses of dry-type transformers, TP-1 recommends a single reference temperature of 75°C as a substitute for five temperatures at the rated load corr p ding to five insulation classes . To assess soundness of such a selection, reduced ope tin mperatures were calculatedat 50% and 3S% of rated load for all five temperature cla of dry-typ ' sulation and for liquidimmersed insulation. The relationship whereby the t per re rise (AT) is proportional to the 0.8th power of the dissipated power (W) was used fort calculation. Thus, AT = kW-, where k is a constant. The assumption was made t the rated d 75% of dissipated power is the load loss , the remainder no-load (core) loss. The results are summarized ' ble 1-A both the 50% and 35% of the rated loads. It is instructive to note that for d e tr ormers out of 10 estimated reference temperatures five are below 75°C, four are above one exactly on. Thus, the selected value in TP-1 represents a reasonable compromise , eeciallf each of the 10 groups were to have similar installed kVA capacity. It should be noted that alternative choices for reference temperatures are feasible, for example, to retain the same reference temperatures for the load losses as in ANSI C57.12.00 and ANSI 057.12. 01, but to make an allowance in the minimum efficiency requirement for the possible overestimation of the magnitude of losses using the temperature corresponding to the rated load . We invite comments by the interested groups and individuals on this matter.

7 

### I NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** load losses to a different reference temperature is a computational operation using a well established algorithm published in ANSI C57.12.90 and ANSI C57.12.91. For load losses ofdry-type transformers, TP-l recommends a single reference temperature 6f75°C as a substitute for five temperatures at the rated load corr ing to five insulation classes. To assess soundness of such a selection; reduced ope at 50% and 35% ofrated load for all five temperature cl ulation and for liquidimmersed insulation. The relationship whereby the t re rise (6.T) is proportional to the 0.8th power ofthe dissipated power (W) was used for t culation. Thus, 6.T = kWO· 8, where k is a constant. The assumption was made t d 75% ofdissipated power is the load loss, the remainder no-load (core) loss. The results are summarized . both the 50% and 35% ofthe rated loads. 

### It is mstructive to note that fbr d ers out of 10 estimated reference temperatures five are below 75°C, four are above Thus, the' selected value in TP-l represents a reasonable compromise, f each ofthe 10 groups were to have similar installed kVA capacity. It should be noted that alternative choice.s for reference temperatures are feasible, for example, to retain the same reference temperatures for the load losses as in ANSI C57.12.00 and ANSI C57.12.01, but to make an allowance in the minimum efficiency**requi~ement** for the possible overestimation ofthe**~agnitude** oflosses using the temperature corresponding to the

, " rated load. We invite comments by the hiterested groups and individuals on this matter.

7KIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

3. Basic Model With regard to the residential appliance programs, 10 CFR 430.2, the term "basic model" is defined as follows: "Basic model means all units of a given type of covered product (or class thereof) manufactured by one manufacturer and [with respect to hers, for example} which do not have any differing physical and functional characteristi tha ect energy consumption." DOE is considering a similar definition for transfo rs: "Basic del means all units of a given type of covered equipment (or class thereof) ufa ured by a single manufacturer and, with respect to distribution transformers, which have the a rating, have electrical characteristics that are essentially identical, o not have y differing physical or electrical characteristics which affect energy consumpti " For the purpose of this definition, "rating" means standard output po ting, sui,s one of those tabulated in NEMA TP 1, tables 4
- 1 and 4-2, reproduced as s 1 and 2 . These power ratings are also the preferred ratings from ANSI C57.12. 00-1993 liquid
-immersed transformers and ANSI C57.12. 01-1989 for dry-type transform The Department cipat that this definition will separate the various types of transformers according to the ominal power (kVA) rating, insulation type (liquid-immersed. or dry-type), number of phases ( single or three) and the voltage rating range (medium-voltage and low-voltage for dry-type transformers).
4. Measures of Energy Consumption DOE is proposing in today's notice three interrelated measures of energy consumption: 8 

### Ti NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE*************************************************************~****************** 

### 3. Basic Model With regardto the residential appliance programs, 10 CFR 430.2, the term "basic model" is defined as follows: "Basic model means all units of a given type ofcovered product (or class thereof) manufactured by one manufacturer and [with respect to hers, for example] which do not have any differing physical and functional'characteristi DOE is considering a similar definition for trans:fi del means all units ofa given type ofcovered equipment (or class thereof) red by a single manufacturer and, with respect to distribution transformers, which have the rating, have electrical characteristics that are essentially identical, y differing physical or electrical characteristics which affect energy consumpti cy." For the purpose ofthis definition, "rating" means standard output POWfillllflilt one ofthose tabulated in NEMA TP 1, tables 4-1 and 4-2, reproduced 1 and 2. These power ratings are also the preferred ratings from 

### ANSI CS7.12.00-1993 i tiid-imrnersed transformers and**AN~I** CS7.12.01-1989 for dry-type transform that this definition will separate the**vario~s** types of transformers according to the ominal power (kV A) rating, insulation type (liquid-immersed. or dry-type), number ofphases (single or'three) and the voltage rating range (medium-voltage and low-voltage' for dry-type transformers).


### 4. Measures of Energy Consumption
DOE**i~** proposing'in today's notice three interrelated measures**ofener~** consumption:. 8NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

(a) total transformer losses , (b) transformer efficiency, and (c) estimated annual energy consumption (EAEC). All these measures are tentatively considered using loading parameters of NEMA TP 1 at 50% of the-rated load for liquid-immersed and medium-voltage dry-type transformers and at 35% of the rated load for low-voltage dry-typ r sformers. DOE considers efficiency as the preferable measure of energy consumption . in stry practice, as required by the cited ANSI standards , has been to measure and repo nsformer 1 s. DOE believes that for energy conservation purposes efficiency is a bett ea re as it is a normalized measure and allows trade
- offs between the two types of losses . The artment would like comments on this measure of energy consumption and the pra ty of its us or the DOE test procedures.

The Code of Federal Re tions (CFR), in 10 CFR Part 430 §430. 23 outlines in general terms the sam g plan co Hance testing. For example , under §430.23 (q)(1), "For each basic model of fluor ent -la p ballasts , as defined in paragraph (14) of §430 .2, a sample of sufficient size, no less than fo shall be tested to insure that ... (ii) Any represented value of the ballast efficiency factor or other measure of energy consumption of a basic model for which consumers would favor a higher value shall be no greater than the lower of (A) the mean of the sample or (B) the lower 99 percent confidence limit of the true mean divided by 0.99." The sampling plan for enforcement testing is provided in 10 CFR Part 430 §430.70, Appendix B. This sampling plan is based on the statistical t-test yielding 97.5 percent probability of obtaining a determination of compliance when the true mean efficiency is equal to the 9 . NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE



### *****.*****************.*.**.************** ••••••** •••********************** (a) total transformer losses, (b) transformer efficiency, and (c) estimated annual energy consumption (EABe). All these measures are tentatively considered using loading parameters of NEMA TP 1 at 50% ofthe· rated load for liquid-immersed and medium-voltage dry-type transformers and at 35% ofthe rated load for low-voltage dry-ty sformers. DOE considers efficiency as the preferable measure ofenergy consumption. try practice, as required by

. the cited ANSI standards, has been to measure and repo s. DOE believes that

for energy conservation purposes efficiency is a bett 

# e as it is a normalized measure and allows trade-offs between the two types oflosses. The ment would like comments on this measure ofenergy consumption and the pra or .the DOE test procedures.


### 5. Number ofUnits to be Tested
'ons (CFR), in 10 CFRPart 430 §430.23 outlines in Hance testing. For example, under §430.23 (q)(l), "For p ballasts, as defined in paragraph (14) of §430.2, a sample Of sufficient size, no less than fo hall be tested to insure that ... (ii) Any represented value ofthe ballast efficiency factor or other measure ofenergy consumption of a basic model for which consumers would favor a higher value shall be no greater than the lower of(A) the mean ofthe sample or (B) the lower 99 percent confidence limit ofthe true mean divided by 0.99." The sampling plan for enforcement testing is provided in lOCFR Part 430 §430.70, Appendix B. This sainpling plan is based on the statistical t-test yielding 97.5 percent probability ofobtaining a determination ofcompliance when the true mean efficiency is equal to the 9NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

applicable standard. At this time the Department is considering one of two sampling plans for compliance testing of distribution transformers:. 1) The plan described in §430.23, using the lower'95 perc dence limit, but without s p e c i f y i n g the minimum number of units in the sample (a mini fm .two units is implicitly required to estimate the confidence limit.) "A sample shall be selected and tested camp o nits which are production units, or are representative of production units of the basi odel being tested and shall meet the following applicable criteria. For ea is model istribution transformers, as defined in §430.2, a sample of sufficient size s t to insure that any represented value of transformer efficiency shall greate h t the lower of (A) the mean of the sample or (B) the lower 95% co ce of the estimated true mean divided by 0.999. The divisor, 0.999, is based on the s ercent loss tolerance specified in Table 19, ANSI C57.12.00 and in an id ical tab in SI C57.12.01. 2) A modified ver oft sampling plan for enforcement testing as in 10 CFR Part 430 §430.70, Appendix B. This s pling plan outlined below is based on the statistical t-test yielding 90 percent probability of obtaining a determination of compliance with the target efficiency when. the true mean efficiency is equal to the target efficiency. "A sample of no fewer than five units shall be selected. at random and tested. The measured mean efficiency of the sample shall be in compliance with the mandated minimum efficiency applicable. to the basic model. The compliance shall be demonstrated by the following sampling plan and analysis. 

### 10 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** applicable standard. At this time the Department is considering one oftwo sampling plans for compliance testing ofdistribution transformers: 1) The plan described in §430.23, using the lower'95 per dence limit, but without specifying the minimum number ofunits in the sample (a mini . required to estimate the confidence limit.) "A sample shall be selected and tested comp . "ts which are production units, or are representative ofproduction units ofthe basi el being tested and shall meet the following applicable criteria. For ea istribution transformers, as ddined in §430.2, a sample of sufficient size s to insure that any represented value of transformer efficiency shall t the lower of(A) the mean ofthe sample ot (B) the lower 95% co " ofthe estimated true mean divided by 0.999." The divisor,**0~999,** is based on the s ercent loss tolerance specified in Table 19, ANSI C57.12.00 and in an id sampling plan for enforcement testIng as in 

## 10 CFR Part 430 piing plan outlined below is based on the statistical t-test yielding • 90 percent probability ofobtaining a determination ofcompliance with the target efficiency when the true mean efficiency is equal to the target efficiency. "A sample**of~o** fewer than five units shall be selected.at random and tested. The measured mean efficiency ofthe sample shall be in compliance with the mandated minimum efficiency applicable. to the basic model. The compliance shall be demonstrated by the following sampling plan and analysis. 10MIST DRAFT OF NOI R FOR DIS TRIBUTION TRANSFORMER TEST PROCEDURE

Step 1. Step 2. The first .

sample size (n,) must be 5 or more units. Compute the mean (Xj) of the ured efficiency of the nl units in the first

Step 3: Compute the sample standar ation (SI).the measured efficiency, of the nl

units in the first sample as folio

or (SE(X))'ofthe mean efficiency of the first sample as

SE(X )= , nl
Step 5'. Compute the lower control limit (LCL,) for the mean of the first sample using the

applicaple mandated efficiency (ME) as the desired mean as follows:

11 

# --

.. -'

.. NIST DRAFT OF. NOPR FOR DISTRlBUTION TRANSFORMER TEST PROCEDURE



### .••$* ••

# "''''**'''.''''*.'''••••***••* ••••'''****'''Ii<*'''*'''*''''''••••••.•'''*"''''''''''******•••*'''**'''**''''''* The first Sample size (111)

### m~st be 5 or more units. 

# ,. . 

### Step 1.. 

### Step 2. Compute the mean (X J ) 

### ofthe 

### measured efficiency ofthe 

# "1 urnts in the first

.\ 

### Sample 

# as follows: .where X; 

### is the efficiency ofunit i.



### . Step 3.' Compute the sample standar the**m~asured** 

### efficiency ,ofthe n l



### . Step 4.. de or (SE(X1»ofthemea,n efficiency ofthe first sample as .' '. '. 

### follows: 

# ..

'" . ./


### Step 5. ,Compute the lower control limit (tCL 1) 

### for the mean ofthe first sample using the



## . . applicapJe mandated efficiency (ME) 

### as the desired mean as follows: \ .11 

### .,. - ... ,NIST DRAFT OF NOPR. FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE
LCL I =ME-tSE(XI). Here t is the 10th percentile of a t
-distribution for a sample size of . n, and yields a 90 percent confidence level for a one
-tailed t test. Step 6. Compare the mean of the first sample (X) wit he er control limit (LCL) to

determine one of thefollowing: (i) If the mean of the first sample el the lower control limit , then the, basic model is in noncompliance testing is at an end. (ii) If the mean is equal t eater tha a lower control limit , no final determination of compl c r compliance can be made; proceed to Step 7. Determine the r. a sample size (n) as follows:

where S , and t ve the values used in steps 3 and 5, respectively . The factor 106 - 0.06ME ME(6 - 0.06ME) is based on a 6 percent tolerance in the total losses . Given the value of n, determine one of the following: (i) If the value of n is less than or equal to ni and if the mean efficiency of the first sample ( X,) is equal to or. greater than the lower control limit (LCL) , the basic
12


### T NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

## ********************************************'********************************

Step 6.

Step 7. 

### LC1:1**=ME-tSE(~).** Here t is the lOth percentile ofa t-distribution for a sample size or .n] and yields a 90 percent confidence level for a one-tailed t test. Compare the mean ofthe first sample (X]) wit determine one ofthefollowing: (i) Ifthe mean ofthe first sample' the lower**controllimit~** then the. (li) Step 7. Determine the r e lower control limit, no final compliance can be made; proceed to

1(106

# ~ 0.06ME)f "ME(6
- 0.06ME)

ve the values used in steps' 3 and 5, respectively. The factor ' 106
- 0.06"ME ME(6
- 0.06ME) is based ona 6 percent tolerance in the total losses. Given the value of

### n, determine one ofthe following: (i) Ifthe value ofn is less than or equal to n 1 and ifthe mean efficiency ofthe first sample 

## (X) is equal to 

### or

### gr~ater than the lower control limit (LCL 1) , the basic 12 .NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE model is in compliance and testing is at an
- end. (ii) If the value of n is greater than n,, the basic model is in noncompliance. The size of a second sample n2 is determined to be the t integer equal to or greater than the difference n - n,.: If the value n2 . , calculated is greater than 20

- n,, set n2 equal to 20 - nl. Step S. Compute the combined mean (X2) of el ency of the n, and n2 units of the

combined first and second samples as foil +"2
)) of the mean efficiency of the n, and n2 units in the combined first 04 second samples as follows:

(Note that S, is the value obtained above in Step 3.) Step 10. Set lower control limit (LCL2) to, LCL2 = ME-tSE(X2), where t has the value obtained in Step 5 and compare the combined sample mean 13 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### ****************************************************************************

Step 8.

Step 9.

Step 10. model is in compliance and testing is at an end. (ii) If the value ofn is greater than nb the basic model is in noncompliance. The size ofa second sample 

### n2 is determined to be the t integer equal to or greater than tbe difference 

### n - n l . Ifthe value**~ompute** the combined mean (X 2) of "combined first and second samples as foIl iency ofthe n 1 and 

### n2 units ofthe

Compute the st 

## 2» ofthe mean efficiency ofthe n 

## 1 and 

### n2 units in the combined first

(Note that' SI is the value obtained above in Step 3.)

,Set lower control limit**(LC~)** to,

## wh~r~ t has the value obtained"in Step 5 and compare the combined sample 

# mean 13KIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE (X2) to the lower conmtrol limit (LCL2) to fine one of the following:

(i) If the mean of the combined sample (X2) is less e lower control limit (LCL,2), the basic model is in noncompliance tes is at an end.. (ii) If the mean of the combined sample (X equal to o eater than the lower control limit (LCL2), the basic model ' c pliance and testing is at an end." For the enforcement testing of transformers the artment is considering a. plan similar to 2) above but changing the probability of nation of a compliance from the 10th percentile to the 2.5th percentile. While most distribution trap ers are l tested for losses , as a contractual purchase requirement , ANSI standards d t re su h testing . ANSI 057: 12.00 does not require load loss measurements on routine basis transformers rated for 500 kVA and smaller; only design tests are required . AN C.57. 1 1 d s not require no
-load and load loss measurements on routine basis for transfos rate for 500 kVA and smaller ; sampling approach is required for no-load loss measurements aniffiesign tests for load loss measurements. Manufacturers who produce fewer than 5 units of a basic model during a 180 calendar day period may use the actual measured mean of all transformers of a particular basic model tested during that period as the representative value. In lieu of analyzing data that are based on sampling , manufacturers who measure losses of all transformers of a particular basic model may use mean value of all units of a particular basic model during the previous 180 day period as the representative value. . 14 . NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE



### ****************************************************************************

, . (X 2 ) to the lower conmtrollimit

### (LC~) to fine one ofthe following:

(i) Ifthe mean ofthe combined sample (X;) is less (LCLJ, the basic model is in noncompliance e lower control limit (ii) Ifthe mean ofthe combined sample(X eater than the lower control limit (LCL2), the basic model' pliance and testing is at an end." For the enforcement testing oftransformers the ment is considering a. plan similar to 2) above but changing the probability of e compliance from the 10th percentile to the 2.5th percentile. tested for losses, as a contractual purchase requirement, ANSI standards d h testing. ANSI C57:12.00 does not require load loss measurements on routine basis ansformers rated for 500 kVA and smaller; only design s not require no-load and load loss measurements on routine basis tor transfo for 500 kVA and smaller; sampling approach is required for no-load loss measurements esign tests for load loss measurements. Manufacturers who produce

### fewe~ than 5 units ofa basic model during a 180 calendar day period may use the actual measured mean ofall transformers ofa particular basic model tested during that period as the representative vwue .. In lieu of analyZing data that are based on

### sampli~g, manufacturers who measure losses 

## ?fall transformers ofa

### particu~ar basic model may use mean value of

### all units ofa particular**basi~** model during the previous 1,80 day period as the. representative value. 14NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE TEST PROCEDURE PART 430-ENERGY CONSERVATION PROGRAM FOR CONS UMER PRODUCTS 1. The authority citation for Part 430 continues to. read as Authority: Energy Policy and Conservation Act, Title III, Pa , ended by the National Energy Conservation Policy Act, Title IV, Part 2 by the nal Applia Energy Conservation Act of 1987, and by the National Appliance Conserv on .nendments of 1988 (42 U.S.C. 6291- 6309). 2. Section 430.2 is amended by adding transformers, as follows: § 430.2 D efinitions. del" definition for distribution

"Basic model me s all 'ts of a given type of covered equipment (or class thereof)manufactured by a single man cturer andWith respect to distribution transformers, which have the same rating, have electrical characteristics that are essentially identical , and do not have any differing physical or electrical characteristics which affect energy consumption or efficiency." For the purpose of this definition, "rating" means standard output power rating, such as one of those tabulated in NEMA TP 1, tables 4-_1 and4-2. . 15 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

## ••••••••••••••••••••••••••••••••••••••••••••• *.,'*',•••••• ,""',•••• " ••••• TEST PROCEDURE PART 430-ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS
1. .The authority citation for Part 430 continues to. read as Authority: Energy Policy and Conservation Act, Title TIL, Paended by the National Energy Conservation Policy Act, Title IV, Part 2 by the Energy Conservation Act of 1987, and by the National Appliance Conse endments of 1988 (42 U.S.C. 6291- 6309).
2. Section 430.2 is amended by adding del" definition for distribution transformers, as follows: § 430.2 Definitions. 

## • * * * • ts ofa given type of covered equipment (or class thereof) manufactured by a single ma 

## * * • * • With respect to distribution transformers, which have the same rating, have electrical characteristics that are essentially identical, and do not have any differing physical or electrical characteristics which affect energy consumption or efficiency." For the purpose ofthis definition, "rating" means standard output power rating, such as one ofthose tabulated in NEMA TP**~,** tables 4 -.1 and 4 - 2. 15NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

Distribution transformer means a transformer for transferring electrical energy from a primary distribution circuit to a secondary distribution circuit, or to consumer's service circuit, or between circuits on the consumer's premises. For the purpose of As OE test procedure, the transformers with the following ratings are included : primary to f 480 V to 35 kV, secondary voltage of 120 V to 480 V, rated load for Iiqu' ersed tr. ormers from 10 WA to 2500 WA, for dry- type transformers from 10 kV ; o 20 kVA. Efficiency of a transformer means j ib o of the u output power to the total input power. In practice, the useful output powsubtracting the total losses of the transformer from its input.power. ntransformer varies with the output power as a result of varying load losses. Dry-type transf er m Is a ansformer in which the core and coils are immersed in a gaseous or dry-compoun sulati medium. Liquid-immersed transformer means a transformer in which the core and coils are immersed in an insulating liquid.. . Load losses of a transformer mean those losses which are incident to the carrying of a specified load. Load losses include ohmic (12R) loss in the windings due to load and eddy currents; stray loss due to leakage fluxes in the windings, core clamps, and other parts and the 16
Li NIST DRAFT, OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

## ****************************'*****************************************"'****** * 

## * '" >I< 

## * Distribution transjormer means a transformer for transferring electrical energy from a primary distribution circuit to a secondary distribution circuit, or to consumer's service circuit, or , 'between circuits on the consumer's premises. For the**purpo~e** of , " I OE test procedure, the tranSformers with the following ratings are included: primary secondary voltage of 120 V to 480 V, rated load for liqu,· .... "'UH .. I' onners from 10 kVA

, to 2500 k V A, for dry-type'transformers from 10k V 

## * '" >I< >I< >I< 

### EffiCiency of a transformer means t output power to the total input power. In practice, the useful output power i subtracting the total losses ofthe transformer from its input ,power." .....**~** sformer varies with the output power as a result ofvarying load losseS.
>I< >I< 

## * *' 

## * ansformer in which the core and coils are immersed in 

## a gaseous or dry-compoun medium.
>I< '" 'iI< >I< >I< 

### 'Liquid-immersed transformer means a'transformer in which the core and coils are immersed in an insulating liquid,. '" '" *. '" '" 

### Loadlosses of a transformer mean those losses which are**inciden~'** to the carrying ofa

, . ' specified load. Load losses include ohmic (I2R) loss in the windings due to load and eddy currents; stray loss due to leakage fluxe,s in the windings,' core clamps, and**oth~r** parts and the 16MIST DRAFT OF NOPR. FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

**************************************************************************** loss due to circulating currents in parallel windings or in parallel winding strands . Load losses vary quadratically with the output current and, hence, with the output power. * * * * * Low-voltage dry-type transformer means a transformer jh rimary voltage rated at 1.2 kV and below. * * * * * Medium-voltage dry-type transformer meaqffi trasformer with a primary voltage rated above 1.2 kV.
* * * * * No load (

excitation ) losses ansfo er mean those losses which are incident to the excitation of the transformer. oad s i c ude core loss, dielectric loss, conduction . loss in the windings due to exciting current , d conduction loss due to the circulating currents in parallel windings . These losse ary wit he e itation voltage. * * ,* * * Total losses of a trans er mean the total of the no-load and load losses, excluding losses due to accessories, such as cooling fans. * * * * * Transformer means a static electromagnetic device consisting of a winding, or two or more coupled windings, with a magnetic core for introducing inductive coupling between electric circuits . Transformers are extensively used in electric power systems to transfer power by electromagnetic induction between circuits at the same frequency , usually to change the 17 NIST DRAFT OF NOPR. FOR DISTRlBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** loss due to circulating currents in parallel windings or in parallel winding strands. Load losses vary quadratically with the output Current and, hence, with the output power. 

## * * 

## * * 

## * Low-voltage dry-type transfonner means a transformer 1.2 kV**~d** below. 

### * * * ... ... Medium-voltage dry-type transformer ormer with a primary voltage rated above 1.2 kV. 

## * ... * * 

## * No-load (excitation) losses mean those losses which are incident to the excitation ofthe transformer. . c ude core loss, dielectric loss, conduction, loss in . the windings due to excitin conduction loss due to the circulating currents in parallel windirigs. These losse



## ... * ,II< II< 

## * er mean the total ofthe no-load and load losses, excluding losses due to accessories, such as cooling fans.



## ... ... * * * Transfonner means a static electromagnetic device consisting ofa winding, or two or more coupled windings, 

### with a magnetic core for introducing inductive coupling between electric circuits. Transformers are extensively used in electric power systems to transfer power by electromagnetic induction between

### ~ircuits at the same :frequency, usually to ·change the 17NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

**************************************************************************** amplitudes of the voltage and current. * * * * 3. Section 430.22 is amended by adding new paragraph(s) ows: § 430.22 Test procedures for measures of energy con tion. * * * * * (s) Distribution Transformers. (1) Total power losses ; a ressed in kilowatts, of a liquidimmersed or medium-voltage dry-type trans fftr operated 50% ofthe rated load, or a lowvoltage dry-type transformer operated at 35% clause 5.2.3 of Appendix S to this sk%W for licid; immersed transformers, and clause 5.3.3 for dry-type transformers. (2) Efficiency of a transforme perated continuously at 50% or 35% of rated output power, as appropriate, tenmin in a ordance with clause 5.4 of Appendix S to this Subpart. (3) The estimated V

ual ergy consumption (EAEC), expressed in kilowatthours. per year, for distribution tranperati ng continuously at 50% or 3 5%, of rated output power, as appropriate, shall be the product of (i) the total transformer losses in kilowatts as determined in (s)(2) above, and (ii) the representative use cycle of 8766 hours per year. * * * 4. Section 420.23 is amended by adding new paragraph (s) as follows: § 420.23 Units to be tested. * * * * *. 18 NIST DRAFT OF NOPR FOR DISTRlBUTION TRANSFOFJv.1ER TEST PROCEDURE 

### **********"'*"'************"'*"'************************************************ amplitudes ofthe voltage and Current. 

## '" 

# '" '" '" '"
3. Section 430.22 is amended by adding new paragraph(s) § 430.22 Test procedures for measures of energy con 

### '" '" '" * '" (s) Distribution, Transformers. (1) Total power losses; immersed or medium-voltage dry-:type trans 50% of the rated load, or a lowvoltage dry-type transformer operated at 35% load, determined in accordance with clause 5.2.3 ofAppendix S to this s . -immersed transformers, and clause 5.3.3 for dry-type transformers. (2) Efficiency ofa transform erated continuously at 50% or**~5%** ofrated output

.power, as appropriate, ordance with-clause 

### 5.4 ofAppendix S to this Subpart. ergy consumption (BAEC), expressed in kilowatthours per year, for distribution transfo s operating continuously at 50% or 35%, ofrated output power, 

### , as appropriate, shall be the product of: (i) the total transformer**l~sses** in kilowatts as determined in (s)(2) above, and (ll) the representatiye use**cycl~** of 8766 hours per year. 

## '" 

# '" '" '" 

# '" 4. Section 420.23 is**am~nded** by adding new paragraph (s) as follows: § 420.23 Units to be tested•. 

# '" '" '" 

# '" '" 18KIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE.

(s) (1) [Editorial note: first alternative considered] For each basic model of distribution transformers , as defined in §430.2, a sample of cient size sh be tested to insure that any represented value of transformer efficiency shall be no greater that the lower of (A)'the mean of the sample 'or (B) the 95 % confidence limit of the estimated true mean divided by 0.999. [Editorial note: second alternative considered] A sample of no.fewer than five units shall be sel efficiency of the sample shall be in compliance witli to the basic model. The compliance sa demonstra analysis. Step 1. The first sample Step 2. Compute th

sample as folio random aid tested . The measured mean mandated minimum efficiency applicable by the following sampling plan and
be 5 or more units. measured efficiency of the n, units in -the first

.Step 3 . Compute the sample standard deviation ( S1) of the measured efficiency of the n,

units in the first sample as follows: E&I(X; -X1)2 n1-1

19 •• '["' mST DRAFT OF'**~OPR** FOR DISTRIBUTION l'RANSFORMER TEST PROCEDURE.******************************************~***********************************.** . ,**~.** .'

. /" . . (8) (1) 

### [Editorial note: first ·alternative considered] For each basic model ofdistribution transfonners, as defined in §430.2, 

### a sample of "sufficient size shall be tested to insure that any represented value oftransfonner efficiency shall be 'no greater that the lower of(A )'the mean ofthe sample or (B) 

### the 95% confidence limit**~fthe**

" '.' . . " / . 

### "estimated-true mean divided by 0.999. ' [Editorial note: second alternative considered] , A 

### sample ofnoiewer than five uints shall be sel

efficiency ofthe sample shall be in 

### cOmpliance witH to the basic model. analysis.**St~p** 1. 

### The measured mean

. dated minimum efficiency applicable I I \ ' 

### by the following sampling plan and' .
Step 2. meaSured efficiency ofthe n 1 

### units in·the first

·Step3.· e effiCiency ofunit i. 

### Compute the sample standard deviation (SI) 

### ofthe measured efficienCy ofthe n 1 

### units in .the first ,sample as**follow~:**

19 , I,'MIST DRAFT OF NOPR FOR DISTRIBUTION. TRANSFORMER TEST PROCEDURE

Step 4 . - Compute the standard error (SE(X)) of the mefficiency of the first sample as

follows:

Step 5. Compute the lower control limit (LCI,forie mean of the first sample using the applicaple mandated efficiency (ME) as t desired mean as follows:

Here t is the 10th pe ile of a i tribution for a. sample size of ' n, and yields a 90 percent confi ce le or one-tailed t test. Step 6. Compare the mean o e first sample (X1) with the lower control limit (LCL) to

determi one of foll ng. If t mean f the first sample is below the lower control limit, then the basic rnlff e! is in noncompliance and testing is at an end.

Step 7. (ii) If the mean is equal to or greater than the lower control limit , no final

determination of compliance or noncompliance cap be made ; proceed to Step 7. Determine the recommended sample size (n) as follows:

n 1S1(106 - 0.06ME) = ME(6 0.06M&)

20

1 

### . 

# .,'

..**'~** \ 

# ..

'. ", "

, 'NIST DRAFT OF ,NOPR FOR DISTRIBUTION. TRANSFORMER TEST PROCEDURE

### ********************************'*************************"'*************~. 

Step 4.



### Step 5.



### Step 6,



### Step 

## i Compute the standard error 

### (SE(X 1

# »ofthe mean efficiency ofthe first sample as follows:

'- S' SE(X)=_l " 1 . 

# ,Ft: Compute the lower control limit (Le 

### e mean ofthe first' sample using the

, applicaple mandated efficiency (ME)** ~** 

### ,t

(i) i 

### tribution 'for a sample size of, 

### n 1 

### "and yields a

e first sample (XI) 

### with the lower controllimit (LCL) 

### to
f 

### the first sample is below the lower control limit, then the, el is in noncompliance and testing is at an end. '(ii), If

### the mean is equal to or greater than the lower cont'rollimit, no final determination ofCompliance or noncompliance cap 

### \>e made; proceed to Step 7. Determine the recomn:tended sample size (n) 

### as follows:
n

# ~.{tSl(106**~** o.06ME)f '

'. ME(6,;, O.06ME) 20. .-.FIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE Step 7. Step 7. Determine the recommended sample size (n) as follows:

n= tS,(106 - 0.06ME) ME(6 - 0.06ME) where S, and t have the values used in ste and 5, res ively. The factor

is based on a 6 percent toler the total 09ses. Oven the value of n, determine one of the following' (i) If the value o 's les nor equal to n, and if the mean efficiency of the first sample (X) is equal t r greater than the lower control limit (LCL,) , the basic model i comp ce d testing is at an end. (ii) If the value n is greater than n,, the basic model is in noncompliance. The size of a second sample n2 is determined to be the smallest integer equal to or greater than the difference n - n,. If the value of n2 so calculated is greater than 20 - n,, set n2 equal to 20 - n,. Step 8. Compute the combined mean (X2) of the efficiency of the n, and n2 units of the

combined first and second samples as follows: 21 · NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE



### **************************************************************************** Step 7.

Step 8. Step 7. Determine the recommended sample size (n) as follows:

where SI and t have the values used in ste The factor

is based on a 6 percent toler**G~ven** the value of

### n,

(i) Ifthe value 0 or equal to nt and ifthe mean efficiency ofthe first r greater than the lower control limit (LCL 1) , the basic 

### model i i:l testing is at an end.



### n is greater than 

### nt, the basic model is in noncompliance. The size of a second sample 

### n2 is determined to be the smallest integer equal to or greater than the difference 

### n - nt . Ifthe value ofnz so calculated is greater than 20
Compute the

### combi~ed mean

### ~)ofthe efficiency ofthe n 1 and

### ~2 units ofthe combined first**~d** second samples as follows: 21NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE
_ ni+n2X2 Xin] + n2 i =1 Step 9. , Compute the standard error (SE(X2)) of the meanncy of the n1 and n2 units

in the combined first and second samples as fol

(Note that S1 is the value obt above in Step 10. Set lower control limit (LCL2)

twined in Step 5 and compare the combined sample mean onmol limit (LCL) to fine one of the following:
(i) If the mean of the combined sample (X2) is less than the lower control limit (LCL2), the basic model is in noncompliance 'and testing is at an end. (ii) If the mean of the combined sample (X2) is equal to or greater than the lower control limit (LCLZ), the basic model is in compliance and testing is at an end. (2) Selection of units to be tested -involving basic models having fewer than six units and basic 22
ft NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDuRE 

### ****************************************************************************

Step 9.

Step 10. _Compute the standard error (SE(X 2

## » ofthe mean

;- 

### in the combined first and second samples as fol

(Note that Slis the value obt Set lower control limit**(LC~)**



### . ned in Step 5 and compare the combined sample mean oI,limit**(LC~** 

### to fine one ofthe following:

(i) If

### the mean ofthe combined sample 

# (.r 2

### )is less than the lower control limit (LCLJ, the basic model is in noncompliance'and testing is at an end. (ii) Ifthe mean ofthe combined sample (.X2) 

### is equal to or greater than the lowercontrol.limit(LCL0, the basic model is in compliance and testing is at an end. ,

.(2) Selection ofunits to be testedinvolving basic models having fewer

### th~ six units and basic 22NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

models for which all units are tested . (i) For those basic models of distribution transformers, as defined in §430.2, for which fewer than six units have been produced over the preceding period of 180 calendar days, all transformers produced over that period shall be tested and any represented value of transformer losses, transformer efficiency, annual energy n . mption, or other measure of energy consumption for a basic model shall be the mean v o e tested transformers. (ii) In lieu of using the sampling approach of § 43 (s)(1), all s of a basic model produced during the preceding 180 calendar days ca e t ed and any represented value of transformer losses, transformer efficiency, annual energy nsumption, or other measure of energy consumption for a basic model shall mean val of the tested transformers.

5. Subpart B of Part 43( ame byyaading Appendix S consisting of sections 1, 2, 3, 4, and 5 as follows: Appendix S to Subpart f Pa 430--Uniform Test Method for Measuring the Energy Consumption of Distributio ransformers. 1. Definitions
1.1 ANSI Standard means a standard approved by a committee accredited by the American National Standards Institute. 1.2 IEEE Standard means a standard developed and approved by the Institute of
23


### IT NlST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** models for which all units are tested. (i) For those basic models ofdistribution transformers, as defined in §430.2, for which fewer than six units have been produced over the preceding period of 180 calendar days, all transformers produced over that period shall be tested and any represented value oftransformer losses, transformer efficiency, annual energy mption, ,Or other measure ofenergy consumption for a basic model shall be the mean v (ii) In lieu ofusing the sampling· approach of § 43 s of a basic model**produce~** during the preceding 180 calendar days ca d and any represented value of transformer losses, transformer efficiency,**~ual** energy umption, or other measure of energy consumption for a basic model shall ofthe tested transformers. 

## '"
... 

# '" '" 

# '"
5. Subpart B ofPart 43 a ding Appendix S consisting of sections I, 2, 3, 4, and 5 as follows: Appendix S to Subpart 430-Uniform Test Method for Measuring the Energy Consumption ofDistributio
1. Definitions
1.1· ANSIStandard means a standard approved by a committee accredited by the American National Standards Institute. 1.1' IEEE Standard means a standard "developed and approved by the Institute of 23NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

Electrical and Electronics Engineers . All IEEE standards referenced in Appendix S have been approved or recognized by ANSI. 1.3 ISO Standard means a standard developed and approved by the International Standards Organization. 1.4 NEMA Standard means a standard developed anipp ved by National Electrical ' Manufacturers Association. 1.5 Phase angle error means a measuremen rro introduced by phase angle displacement between voltage and current phasors in the st equipment. Phase angle error, if significant, can introduce errors in measured former los, 1.6 Phase angle correction.' means negate the effects of phase angle err (correction) of measurement data to 1.7 Reference teniperat me he J,einperature , specified in standards , to which the transformer losses shall be corrected d reported. 1.8 Temperatu correc m s Y the adjustment (correction) of measurement data obtained with the transfo r and test at a temperature that is different from the reference temperature to values that wo lffi have been obtained with the transformer at the reference temperature. . 1.9 Test voltage, current , and frequency . mean voltage, current, and frequency of the electric power supplied to the transformer under test. 2.0 Waveform correction means the adjustment (correction) of measurement data obtained with a test voltage that is non
- sinusoidal (distorted) to values that would have been obtained with sinusoidal voltage.
24

11 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### *.* •••************~** 

### ••*** ••••••••* ••************.**.~.*.*** 

### •••****.*.*.****.***.**~.*** Electrical and Electronics Engineers. All IEEE standards referenced in Appendix S have been approved or recognized by ANSI. 1.3 ISO Standard means a standard developed and approved by the Intemation81 Standards Organization. 1.4 NEMA Standard means a standard developed an Manufacturers Association. 1.5 Phase angle error means a measuremen roduced by phase angle displacement between voltage and current phasors in the equipment. Phase angle error, if . significant, can introduce errors in measured 1.6 Phase angle correction 'means th (correction) of**m~asurement** data to negate the effects ofphase angle e 1. 7 Reference temperat e emperature, specified in standards, to which the transformer losses shall be corrected s the adjustment (correction) ofmeasurement data test at a temperature that is different from the reference temperature to values that wo. have been obtained with the transfornier at the reference temperature.

. . . t 1.9 Test voltage, current, andfrequency. mean voltage, current; and frequency ofthe electric power supplied to the transformer under test. 2.0 Waveform correction means the adjustment**(corre~tion)** ofmeasurement data obtained with a test voltage that is non-sinusoidal .(distorted) to values that would have been obtained with sinusoidal voltage, 24NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

2. References. 2.1 ANSI Std . C57.12. 90-1993, "IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers and IEEE Guide for Short-Circuit Testing of Distribution and Power Transformers." 2.2 ANSI Std. C57 . 12.00-1993, IEEE Standard Gen R ' rements for LiquidImmersed Distribution , Power, and Regulating Transfo 2.3 IEEE Std . C57.12.91-1995, IEEE Stand T Code for Dry

- Type Distribution and Power Transformers . • This Standard specifies test metho and certain test conditions for drytype distribution transformers. 2.4 ANSI Std. C57.12. 01-1989, "IEE S eneral Requirements for Dry-Type Distribution and Power Transforms luding use With Solid Cast and/or Resin
-Encapsulated Windings." 2.5 NEMA Standards Public 'on , TP 1-1996, "Guide for Determining Energy Efficiency for Distribution Trans 2.6 ISO Standar 01-1 3, "Quality Systems-Model for quality assurance in design, development, production, inst ation, and servicing." 2.7 Note : specific parts of standards C57.12 . 00-1993 , C57.12 . 01-1989, and C57.12.91- 1995 are designated in their original publications by the term "Section ," similar parts in standards C57.12. 90-1993 and ISO 9002 : 1987 ( E) are designated by the term "Clause ." The use of these terms is retained in.this DOE test procedure. record keeping of calibration data of test and measuring instruments.

25 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** 2. References. 2.1 ANSI Std. C57.12.90-1993, "IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers and IEEE Guide for Short-Circuit Testing of Distribution and Power Transformers. " 2.2 ANSI Std. C57.12.00-1993, IEEE Standard Gen Immersed Distribution, Powet:, and Regulating Transfo 2.3 IEEE Std. C57.12.91-1995, IEEE Stand Code for Dry-Type Distribution and Power Transformers ..This Standard specifies test metho d certain test conditions for dry-

. type distribution transformers. eneral Requirements for Dry-Type

Distribution and Power Transform.efal!ib\C. e With Solid Cast and/or Resin-Encapsulated Windings."

. n, TP 1-1996, "Guide for Determining Energy Efficiency for Distribution Transft 3, "Quality Systems-Model for quality assurance in design, development, production, 

### inst ation, and servicing." 2.7 Note: specific parts of standards C57.12.00-1993,·C57.12.01-1989, and C57.12.91- 1995 are designated in their original publications by the term "Section,'; similar parts in standards C57.12.90-1993 and ISO 9002: 1987(E) are designated by the term "Clause." The use ofthese terms is retained in this DOE test procedure. record keeping ofcalibration data oftest and**~e!lsuring** instruments.

25.KIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

. 3. Test Conditions.

3.1 No-load losses, liquid-immersed transformers. The test conditions for measuring the no-load losses shall be those specified in ANSI Std. 057.12.90-19 a test voltage and frequency given in Clause 8.2.4; the waveform correction giv in use 8 .3; and the temperature correction given in Clause 8.4. ANSI Std. A2.00=199 ecifes in Section 5.9 the reference temperature for reporting the measure
3.2 Load losses, liquid immersed tr rmers . Th est conditions for measuring load losses shall be those specified in ANSI Std. C .1 3 and in ANSI Std. C57.12.00-1993. ANSI Std. C57.12.90-1993 specifie therma gpditions of the transformer under test in Clause 5.1 (includingJits Subcla ) Clause 9.3; the test frequency, the maximum value of correction to the measured load. loss ue to the test system phase angle error, and the minimum size of the conductors d for s rt-ci uiting the terminals in Clause 9 . 3; the magnitude of.the test current in Clause 9 . 3 . ; the mperature correction to the measured load losses in Clause 9.4.2; and the phase angle co ion to the measured load losses in Clause 9.4.1. ANSI Std. C57.12. 00-1993 specifies the reference temperature for reporting the measured load losses at. the rated load in Section 5.9.
3.2.1 For the purpose of this DOE test procedure the load losses of liquid-immersed transformers shall be corrected to 50% of the rated , load value and the reference temperature of 55°C. 26 ,NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE ' 

# •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 3. Test Conditions.
3.1 No-load losses, liquid-immersed transformers. The test conditions for measuring the no-load losses shall be those specified in ANSI Std.**C57.12.90~19** . e test voltage and. frequency given in Clause 8.2.4; the waveform correction giv temperature correction given in Clause 8.4. ANSI Std. ecifies in Section 5.9 the reference temperature for reporting the measure


### 3.2 Load losses, liquid-immersed fr, Th est conditions for measuring load losses shall be those specified in ANSI Std. C 3 and in ANSI Std. C57.12.00-1993. ANSI Std. C57.l2.90-1993 specifi ditions ofthe transformer under test in Clause 5.1 (including"its Subcla . CI use 9.3; the test frequency, the maximum value of**correc~ion** to the measured load, loss ue to the test system phase angle error, and the minimum size ofthe conductors iting the terminals in Clause 9.3; the magnitude ofthe test current in Clause 9.3. mperature correction to the measured load losses in Clause 9.4.2; and the phase angle co ion to the measured load losses in Clause 9.4.1. ANSI Std. C57. 12.00-1993 specifies the reference temperature for reporting'the measured'load**losse~** at the rated loa,d in Section 5.9,

! 3.2.1 For the purpose ofthis DOE test procedure the load

### 10sse~ pfliquid-immersed transformers shall be corrected to 50% of.the rated, load value and the reference temperature of

26KIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

3.3 No-load losses, dry-type transformers. The test conditions for measuring no-load losses of dry-type distribution transformers shall be those specified in ANSI Std. C57.12.91-1995: the rated voltage and frequency are specified in Section 8.2.4; the A horm correction to sinusoidal conditions is specified in Section 8.3.
3.3.1 In addition, during the measurement of -loll losses , the average temperature of the core shall be measured or determined from ambient c ditions. 3.3.2 For the purpose of this DOE to pr e , the no-load losses shall be measured at or corrected to the reference tem ure of 3.4 Load losses, dry- ans ers The test conditions for measuring the load losses of dry-type distribution transformers all be those specified in ANSI Std. C57. 12.91-1995 and in ANSI Std. 057.12. 01- 9: St 057.12:91-1995 specifies the conditions for determining the temperature of the wi ngs i ections 5.2 and 9.3; the size of conductors and precautions for short- circuiting the wind ' are given in Section 9 . 3; and the test frequency is specified in Section 9.3. ANSI Std. C57.12 .01-1989 specifies in Section 5.9 that-the load losses shall be based'on a reference temperature equal to the rated average winding temperature rise plus 20°C. The rated average winding temperature rises for five insulation system temperatures are listed in Table 4A of ANSI Std. C57.12.01-1989.
3.4.1 For the purpose of this DOE test procedure ,. the load losses of dry-type
27 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### ***************************.************************************************
3.3 No-load losses, dry-type transformers. The test conditions for measuring no-load losses ofdry-type distribution transformers shall be those specified in ANSI Std. C57.12.91-1995:

. _ the rated voltage and frequency are specified in Section 8.2.4; the sinusoidal conditions is specified in Section 8.3 .. 3.3.1 In addition, during the measurement of losses, the average temperature of the core shall be measured or determined from ambient c
3.3.2 For the purpose ofthis DOE te , the**no~load** losses shall be measured .' at or corrected to the reference tern

. 3.4 

### Load losses, dry- he test conditions for measuring the load losses ofdry-type distribution transformers I be those specified in ANSI Std. C57.12.91.. 1995 and in ANSI Std. CS7.12.01- 57.12;91-1995 specifies**~he** conditions for determining ections 5.2 and 9.3; the size ofconductors and precautions for short-circuiting the wind' are given in Section 9.3; and the test frequency is specified in Section 9.3. ANSI Std. C57.12.01-1989 specifies'in Section 5.9 thatthe load losses shall be based'on a reference temperature equal to the rated average winding temperature rise plus 20°C. The rated average winding temperature rises for five insulation system temperatures are listed in Table 4A of ANSI Std. C57.l2.01-1989.
3.4.1 For the purpose ofthis DOE test procedure, the load losses ofdry-type 27.KIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

transformers shall be corrected to 50% of the rated load for medium-voltage transformers, to 35% ofthe rated load for low-voltage transformers , and to the reference temperature of 75°C.
4. Test Methods and Instrumentation, 4.1 No-load losses, liquid-immersed transformer he test me d and instrumentation shall be those specified in ANSI Std. 057.12.90-199 laie 8 .2 and all its Subclauses. 4.2 Load losses, liquid-immersed tr rmers. Th est methods and instrumentation shall be those specified in ANSI Std . C57.12. - 1 use 9.3 and all its Subclauses. Resistance and temperature measur ts, ge n for measurement of load losses, shall be performed according to Clause , 5. d 5 3 (including all Subclauses) of ANSI Std: C57.12.90-1993. 4.3 No-load lose e transformers. The test method and instrumentation shall be those specified in ANSI Std. 12.91-1995, Sections 8.2.1, 8.2.2, and 8.2.3. 4.4 Load losses, dry-type transformers. The test method and instrumentation shalt be those specified in ANSI Std. C57.12.91-1995, Sections 9.3.1, 9,3.2, and 9,3.3.4. Resistance and temperature measurements, germane for the measurement of load losses , shall be performed according to Sections 5.4 (including all Subsections) of ANSI Std. C57.12.91-1995.

28 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** transformers shall be corrected to 50% ofthe rated load for medium-voltage transformers, to 35% ofthe rated load for low-voltage transformers, and to the reference temperature of75°C.


### 4. Test Methods and

### Instrumentation.
4.1 No-Iocld losses, liquid-immersed transformer. 

### aand instrumentation shall be those specified in ANSI Std. C57.l2.90-199


### 4.2 Load losses, liquid-immersed tr est methods and instrumentation

, shall be those specified 

### in ANSI Std. C57.12.
- use 9.3 and all its Subclauses. Resistance ,and temp·erature·measur for measurement oflQad losses, shall be performed according to Clause 5 3 (including all Subclauses) ofANSI Std. C57.12.90-1993.



### e transformers. The test method and instrumentation shall be those specified in ANSI Std. .12.91':'1995,**Secti~ns** 8.2.1,8.2.2, and 8.2.3.


### 4.4 Load losses, dry-type transformers. The test method**~d** instrumentation shall be those specified in ANSI Std. C57.12.91-1995, Sections 9.3.1, 9.3.2, arid 9,3.3.4. Resistance and temperature measurements, germane for the measurement ofload losses, shall be performed according to Sections 5.4 (includIng all Subsec,tions) ofANSI Std. C57.12.91-199S.

28NIST DRAFT OF NOPR FOR. DISTRIBUTION TRANSFORMER. TEST PROCEDURE

4.5 Accuracies required for measuring no-load and load losses of liquid

-immersed and dry-type distribution transformers shall be those specified in ANSI Std. C57.12.00-1993, Section 9.4. 4.6 Test equipment and measuring instruments shall ained and calibrated, calibration records maintained to ensure compliance with previous c e 4.5
. Guidance of general quality assurance procedures in testing is ava ' le ' the following cited Clause 4.11.1 of ISO Standard 9001-1993, "Quality Systems-Model for ity assurance in design, development , production , installation, and s "The supplier shall establish and mat and maintain inspection, in ented procedures to control, calibrate equipment (including test software) used by the supplier to demons the armance of product to the specified requirements. Inspection, measurin and to qulpment shall be used in a manner which ensures that measurement u ertain kn n and is consistent with the required measurement capability. "
5. Measurements and Calculations.
5.1 Measure the no load and load losses of a transformers according to test methods in Clause 4 of this .Appendix. 5.2 Calculate the load losses of liquid -immersed transformers based on operation at 50% 29 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** 4.5 Accuracies required for measuring no-load and load losses ofliquid-immersed and dry-type distribution transformers shall be those specified in ANSI Std. CS7.12.00-1993, Section 9.4.
4.6 Test equipment and measuring instruments shall

.calibration records maintained to ensure compliance withe4.5. Guidance of general quality assurance procedures in testing is ava' the following cited Clause 4.11.1 of ISO Standard 9001-1993, "Quality Systems-Model for development, production, installation, and s "The supplier shall establish and mai ented procedures to control, calibrate and maintain inspection, mequipment (including test software) used by the supplier to demons ance of product to the specified requirements. ipment shall be used in a manner which ensures that measurement u and is consistent with the required measurement capability. "
5. Measurements and Calculations.
5. J Measure the no-load and load losses ofa transformers according to test methods in· Clause 4 ofthis Appendix.
5.2 Calculate the load losses ofliquid-immersed transformers based on operation at 

## sq% 29MST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

of the rated output power.
5.2.1 Correct the measured no-load loss data of liquid-immersed transformers to sinewave basis according to-ANSI Std. C57.12.90-1993, Clause
5.2.2 Correct the measured load loss data of ersed t formers for phase angle errors in measuring instruments , if significant, rd g to 'ANSI Std. 057.12.90-1993, Clause 9.4.1.
5.2.3 Correct the no-load and load 1o v e Clauses 5.2.1 and 5.2.2 to reference temperature of 20°C for no-load to rid 55 ° f r load Josses and add the two to obtain the total losses based on operation 0% e r ted output power.
5.3 Calculate a load ses dry-type transformers based on operation at 50% or 35% of the rated output p ter, a ppropriate.
5.3.1 Correct the measured no-load loss data of dry-type transformers to a sinewave basis according to ANSI Std. C57.12.91-1995 , Section 8.3. .
5.3.2 Correct the measured load loss , data of dry-type transformers for phase angle errors in measuring instruments, if significant , according to. ANSI Std. C57.12.90-1993, Clause 9.4.1.

30 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** ofthe rated output power.
5.2.1 Correct**t~e** measured no-load loss data ofliquid-immersed transfonners to sinewave basis according to, ANSI Std. C57.12.90-1993, Clause
5.2.2 Correct the**measur~** load loss data ofliq' . onners for phase angle errors in measuring instruments, if significant, Clause 9.4.1.
5.2.3 Clauses 5.2.1 and 5.2.2 to reference temperature of20°C for no-load 10 

### :6 r load 

### losses and add the two to obtain the total losses' based on operation
,5.3 Calculate dry-type transformers based on operation at 50% or

5.3.1 Correct the measured no-load loss data ofdry-type transformers to asinewave basis according to ANSI Std. C57.12.91-1995, Section 8.3.
5.3.2 Correct the measured load loss, data ofdry-type transfonner.s for phase angle errors in measuring instruments, if significant, according to ANSI Std. C57.12.90-1993, Clause 9.4: 1.

30NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

5.3.3 Correct the no-load and load loss values of Clauses 5.3.1 and 5.3.2 to reference temperature of 20°C for no-load losses and 75 'C for load losses. Add the temperature-corrected no-load loss and load loss values to obtain the total losses based on operation at. 50% or 35% of the rated output power, as appropriate. 5.4 Calculate the efficiency in percent of transf rs operatin 50% or 35% of the rated output power, as appropriate by using the equ E50(35) = 100 { P50(35) I (P50 (35) + 5) )], where ESO(35) is the efficiency of the transfo n percent en operated at 50% (35%) of the rated output power, P50(35) is the output powe 0% or 35 % of the rated (nameplate). value, and £50(35) is the total loss po f the tr s rmer in kW at 50% or 35. % of the rated output power.

31 . NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE********************************~*********************************************** 5.3.3 Correct the no-load and load loss values ofClauses 5.3.1 and 5.3.2 to reference temperature of20°C for no-load losses and 75 °C for load losses. Add the temperature-corrected no-load 

### loss and load loss values to obtain the total**J~sses** based on operation**a~·** 50% or 35% of the rated output power, as appropriate.
5.4 Calculate the efficiency in percent oftransfi 50% or 350/0 ofthe rated output power, as appropriate by using the equ E

SO(3S) 

### = 100 [ P50(35) I ( P50(35) where E S0(3s) is the efficiency ofthe transfo rated output power, P 50(35) is, the output powe value, and 

### 1 50(35) is the total loss po output power.

31. n operated at 50% (35%) ofthe

. 0% or 35 % ofthe rated (nameplate) nner in kW at 50% or 35 % ofthe ratedKIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

Table 1 Preferred Standard kVA Ratin Liquid-Immersed Distribution Try

667 833 1000 1500 2000 2500 s

32 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFOR1vfER TEST PROCEDURE 

### ••••••••••••••••** ••**.**.*** ••* •••*,•••••••••••••**** ••••* •••** ••••••••••••

Table 1 Preferred Standard kVA Ratin Liquid-Immersed Distribution Tr Single-Phase Power Rating, kVA



### 10 

### 15 25 

### 37.5

50 

### '75 100 167 

### 250 

### 333 500 667 

### 833 150 225 300 500 

### 750 1000 

### 1500 2000 2500

32MST DRAF T OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE

Table 2 Preferred Standard kVA Rating Dry-Type Distribution Transform

Low Medium Voltage, Voltage, s 1.2 kV > 1.2 kV

33 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

## *

••••••*•• * ••••* •••**~** 

### ••*** ••*.*****.**********.***** •••••******.*****.******.

Power Rating,

kVA



### 15 .25 37.5 50. 75 ·100.

167 250 333 

### 50.0 667 833 Table 2 Preferred Standard kVA Rating Dry-Type Distribution Transfo Single-Phase
Low Voltage,**~** 

### 1.2 kV



### 112.5 150. 225 30.0. 500 750. 100.0. 1500 20.0.0. 250.0.

33 Low Voltage, s: 

### 1.2 kV Medium Voltage, > 

### 1.2 kVKIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFO R TEST PROCEDURE Table 1-A

°C Reference Temperature °C . 1 °C °C Liquid- Immersed 85 1 65.
130 60 150 80 185 115 200 130 220 150' 85 80 100 135 150 170 35

30 .40 

### 60 65 75 Assumptions: No-load losses 25%; load losses 75% Algorithm : aT=kW AT - - temperature rise W - - dissipated power k - - constant AT rounded off to the nearest 5°C Calculated Temperature Rises for Transformers Operated at Lower Than The Rated (Nameplate) Load Insulation System Temperature Rating Temperature Rise at

Rated Load Temperature Rise at 50% of Rated Load Estm. Reference

Temperature at 50'% of Rated Load °C

50 60 25

35 80 50 85 55 95 65

Temperature Rise at 35% ofRatedLoad Estm. Reference

Temperature at 35% of Rated Load °C

45 55 70 75 85

.34 NIST DRAFT OF NOPR FOR DISTRIBUTION TRANSFORMER TEST PROCEDURE 

### **************************************************************************** Table I-A Calculated Temperature Rises for Transformers Operated at Lower Than The Rated (Nameplate) Load Insulation Temperature Rise at

System Rated Load Temperature Rating °C 

### °C 85 65 130 60 150 80 185 115 200 130 220 150 . Reference Temperature Rise at Estm. Reference Temperature SO"..4 ofRated Load Temperature at SO"..4 ofRated Load °C °C °C

.- Liquid-Immersed 

### 85 35 55 Dry-Type 

### 80 30 50 100 .40 60 135 60 80 150 65 85 170 75 95 Assumptions: No-load losses 2S%; load losses 7S% AJgoritlnn:**AT=k~~**

AT- .. temperature rise W .... dissipated power k .... constant AT rounded offto the nearest SoC
.34 Temperature Rise at Estm. Reference 3S% ofRated,Load Temperature at 3S% ofRsted LOad' °C °C



## - 

# - - 

# - 25 45 35 55 50 70 55 75 . 65 85