POWER QUALITY WORK 

AT THE INTERNATIONAL ELECTROTECHNICAL COMMISSION 

Franyois Martzloff 

National Institute of Standards and Technology* 

Gaithersburg MD 20899 USA 

Abstract 

The paper presents an update, including a brief historical background, on the work to be undertaken at 

the International Electrotechnical Commission (IEC) to address power quality issues. To be useful, this 

work must take into consideration the three principal stakeholders, namely the producers of electric 

power, the manufacturers of equipment that use electric power, and the users of that equipment. Other 

stakeholders include manufacturers of power quality monitors, manufacturers of line conditioners, and 

power quality consultants. At this time there are some differences of perceptions on how the work can 

be accomplished to best serve the interests of all stakeholders. Nevertheless, there is no disagreement 

on the first goal to be reached, which is to catalyze development of compatible, comparable, and 

consistent results in the measurement of power quality parameters. 

Introduction 

In a landmark 1996 decision, the Committee of Action of the IEC approved a recommendation to 

undertake work on power quality issues as part of the scope of Technical Committee TC77 on 

Electromagnetic Compatibility (EMC). This decision, recommended by an Ad Hoc Group composed 

of power quality experts from ten countries, marks an expansion of the scope that will then reach beyond 

the purely technical issues generally addressed by the EMC community. Power quality and EMC share 

many concerns, to the point that each has at some time been described as being a subset of the other. In 

addition to this fundamental aspect, other issues permeate any discussion of power quality. It would be 

more accurate to draw a multi-dimension diagram with many overlaps (see Figure 1). The Ad Hoc 

Group considered three areas of contributions which an IEC Power Quality Group could make, 

complementing the work currently done by existing working groups or project teams of TC77: 

- Bringing order to the present chaos of uncoordinated methods of monitoring power quality 

- Proposing a classification of power quality levels describing what end-users can expect 

- Building bridges among producers and users of electric power, and equipment manufacturers 

Concerns have surfaced that undertaking such work might ultimately result in the development and 

imposition of standards on the quality of "electricity as a product" and create an adversarial relationship, 

where for the moment the emphasis is on cooperation. There is a need to reduce these concerns by 

defining more clearly the objectives and work program of this new IEC activity. 

* Electricity Division, Electronics and Electrical Engineering Laboratory, Technology Administration, 

US. Department of Commerce. 

Contributiom from the National Institute of Standards and Technology are not subject to U.S. Copyright. 
Power quality issues involve overlapping stakeholders' interests or technical aspects 

in many domains. In this figure, four domains are represented as planes in an 

exploded view, showing how for each domain, developing a Power Quality (PQ) 

document will involve overlapping topics and draw upon the interests and expertise 

of the stakeholders. A successful development will integrate all topics in each 

domain, and consolidate all domains into one entity. (Note how the artist has 

provided registration pegs on the planes so that the re-assembly will be a good fit !) 

Figure 1 - The many dimensions of power quality issues 

Power Quality in Other Organizations 

The term "Power Quality" first appeared in the U.S. literature in the late seventies 'z2 23, used at first by 

the computer-user community in a somewhat negative context, as it seemed to be associated with 

anecdotes or complaints of malfunctions attributed - correctly or incorrectly - to "poor power quality." 

At the beginning, there was a tendency to look for a culprit, the users blaming the electric power being 

supplied to them, and the electric power supplier blaming insufficient immunity of the equipment to 

unavoidable disturbances. 

Even when a solution was indeed in sight, there remained among some stakeholders some reluctance to 

assume the cost of correction, and attempt to pass it on to the other stakeholder(s). The "boundary" of 

the stakeholders was often defined as the revenue meter, as if electrons would change their behavior 

when going through the current coil of the meter. 
Technically sound and economically viable solutions will depend on the cooperation of three principal 

stakeholders: 

- Producers of electric power; 

- Manufacturers of equipment that uses electric power; 

- Users of equipment that uses electric power. 

Perhaps not immediately obvious, but three other important stakeholders in correcting power quality 

problems are: 

- Manufacturers of power quality monitoring instruments; 

- Manufacturers of line conditioning equipment; 

- Consultants called upon to solve power quality problems. 

Considerable progress has been made since the early days in bringing the parties together to seek 

mutually satisfactory solutions rather than hunt for culprits. The PQA conferences held in the last 

several years are a good indication of this change of mood and mode. We now hear the word "interface" 

more often than the word "boundary" suggesting that disputes are being replaced by constructive dialog. 

The term and concept of "System Compatibility" have also become more visible 4. 57 6. ', with the goals 

of the utilities defined as making their customers satisfied and helping customers to be more competitive, 

rather than merely supplying them with electric power. 

Many electric utilities have instituted power quality programs in their customer services, some as a 

defensive or reactive step, others as a proactive and marketing strategy. Engineering societies have also 

focused on practical, application-oriented power quality issues, while initially the standards activities 

were slow in reacting to the growing interest in those issues. Since then, several organizations have 

established power quality programs for developing standards or contributing to the development of 

standards, including the Canadian Electricity Association (CEA)', the European Committee for 

Electrotechnical Standardization (CENELEC)9, the Electric Power Research Institute (EPRI)lO, the 

Institute of Electrical and Electronics Engineers (IEEE)", and the International Union of Producers and 

Distributors of Electrical Energy (UNIPEDE)'2. All of these organizations have allocated substantial 

resources to address power quality issues. 

One of these issues in particular is the incompatibility found when attempting to analyze and compare 

the results of power quality surveys based on different definitions or measurement methods 13. 14, 15. This 

incompatibility is rooted on different definitions of disturbances, and hence different algorithms in the 

software of power quality monitoring instruments. Eliminating these incompatibilities is one of the 

prime motivations for the proposed IEC work that will first focus on measurement methods. 

Power Quality vs. Voltage Quality 

At the risk of oversimplification, one can identify two different approaches to addressing power quality 

issues on the two sides of the Atlantic Ocean. In Europe, attention seems to have focused on the "voltage 

quality" while in North America, the concerns fell under a broader umbrella of "power quality." While 

the difference may seem to be a mere linguistic subtlety between the U.K. English which is the official 

English of the IEC and the U.S. English which is the unofficial English of the IEEE, the words also 

reflect a difference in perspective. In French, the second official language of the IEC, one finds the label 

of "qualit6 de la tension" (tension = voltage), reflecting the emphasis on voltage. Perhaps as a result of 

this difference of perceptions, the few existing bilingual IEC documents on the subject have not yet 

provided a satisfactory equivalent in the two languages 

An anecdote can best illustrate this subtle perspective difference: in what the U.S. community would 

recognize as a power quality pamphlet influenced by the European Community, the untranslatable 

caption of a cartoon from Electricite de France, "Bien vivre avec sa fension" (Figure 2) proposes the 

double-entendre of learning to live with "tension" - understood as the blood pressure of the end-user, 

or "tension" - understood as the system voltage. Hopefully, there will not be a triple-entendre where 

the word "tension" would refer to a sag, or to strained relations among the three principal stakeholders, 

resulting from concerns over the forthcoming IEC work on power quality issues. The caption of Figure 2 

is an attempt at providing in the power quality context a culturally-equivalent rendition of the French 

for an English-speaking audience. 
& 

Courtesy: Electricit6 de France 

Figure 2 - Live long and prosper with your power quality 

Somewhat in contrast with the emphasis on voltage -but certainly not in conflict - the U.S. perspective 

has included more than just supply voltage in the power quality issues. An often-cited statement in 

power quality articles is " ... 83% of the alleged power quality problems are actually end-user wiring 

problems" and one article even shows a screwdriver as "the primary tool for solving power quality 

problems." This broad perspective is also illustrated by an IEEE standard, part of the ZEEE Color Books 

series, on powering and grounding for sensitive loads " which is clearly related to power quality issues. 

Satisfactory Operation vs. Voltage Quality 

During the proceedings of the IEC Ad-Hoc Group meeting held in April 1996, interesting discussions 

took place among the participants on their respective proposals for a definition of power quality - a 

necessary prerequisite to undertaking work on the subject. A compromise consensus emerged so that 

the group would be able to present a recommendation for action where the terms would be defined. One 

of the proposals had emphasized the voltage parameters, while another proposal had related power 

quality to satisfactory operation of the user's equipment. The resulting definition, cited below, still 

reflects these two points of view: 

Power Quality - Set of parameters defining the properties of the power supply as 

delivered to the wer in normal operating conditions in terms of continuity of supply and 

characteristics of voltage (symmetry, ji-equency, magnitude, waveform). 

Note I: Power Quality expresses the users' satisfaction with the supply ofelectricity. Power 

Quality is good ifelectricity supply is within statutory and any contractual limits, and there are 

no complaints from users, and vice-versa it is bad ifthe power supply is outside oflimits and 

there are complaints from users. 

Note 2: Power Quality depen& not only on the supply but can be strongly aflected by the users' 

selection of equipment and installation practices. 

It will be one of the tasks (challenges?) of the group working on the forthcoming documents to allocate 

appropriate attention to the two points of view rather than to consider them as mutually exclusive. 
Forthcoming IEC Work on Power Quality 

The approach now being considered by the IEC is to initially limit power quality work to measurement 

methods, and perhaps even to a narrower limit of characterization of voltage parameters. Starting with 

measurement methods certainly is a necessity to get the work under way and ensure that all parties speak 

the same language when discussing power quality parameters. However, stopping there, useful as it may 

be to catalyze compatible dialog between producer and consumer of electric energy (power) will not be 

sufficient to fulfill the expectations of equipment users. From all the fuss about power quality being 

addressed at the IEC, they expect that more satisfactory operation of their equipment will be facilitated 

by the commitment of resources now envisaged by contributors to the IEC process, and that objective 

and reliable guidance will be found in the new documents. 

As mentioned in the Introduction, an Ad-Hoc Group of representatives from several national or 

international organizations and committees developed a recommendation to begin work on power 

quality, starting first on measurement methods. This priority is a recognition of the present 

uncoordinated efforts among dedicated, but isolated, organizations which have produced incompatible 

or contradictory results among power quality surveys conducted by different organizations. The decision 

by the IEC Committee of Action to accept the recommendation developed by the Ad-Hoc Group has 

now cleared the way for New Work Item ProposaIs (NwIP), the method used by the IEC to launch the 

development of new documents, to be submitted to the IEC National Committees for approval. 

As of the writing of this paper two NWP proposals have been circulated. One, originating from the 

French National Committee, has the title "Measurement Guide for Voltage Characteristics" while the 

other, submitted by the U.S. National Committee, has the title "Power Quality Measurements" again 

reflecting the difference in perspective. The French proposal somewhat mirrors the UNIPEDE l2 

approach while the U.S. proposal includes all the topics listed by the Ad-Hoc Group as well as a 

reference to the IEEE Standard 1 159 16. The French proposal concentrates on low-frequency disturbance 

characterization, including power frequency, voltage magnitude, voltage fluctuations, voltage dips, 

harmonic voltages, and signalling voltages, but downplays transient overvoltages (surges). It also makes 

several references to "Compliance with EN 50160"" which might be seen as leading to mandatory 

clauses. The US. proposal includes a comprehensive list of disturbances, suggests tutorial clauses on 

definitions and origins of disturbances, and even the possibility of providing some tutorial material on 

remedial or preventive actions. Both proposals follow the Committee of Action decision that Technical 

Committee TC77 should be the principal responsible committee for this work, in coordination with 

Technical Committee TC8 (Standard voltages, current ratings and frequencies). 

The officers of TC77 are on record as recommending that the two proposed projects be merged into a 

single project since it is clear that both proposals share the same goal of developing compatible, 

comparable, and consistent results in the measurement of power quality parameters. The responses 

from the National Committees will not be compiled before late June 1997, but some responses will be 

known by the time of presentation of this paper. Hopefully, the responses will be positive and the paper 

presentation will include an update on the project planning. 

Conclusions 

a The first step has been taken at the IEC to start working on the development of documents 

addressing power quality issues. 

* The challenge will now be to proceed diligently to satisfy the needs of end-users and not have the 

work stalled by the diff~culties of reaching consensus among many stakeholders. 

a The decision to start with measurement methods will enable development of a common language and 

build a working relationship among the participants which should promote continuing progress 

toward technically sound and cost effective solutions for the problems perceived - correctly or 

incorrectly - as power quality problems encountered by end-users in the equipment operation. 
gg 

Qy

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