National Electrical Manufacturers Association

2101 L Street, N.W. Suite 300

Washington, D.C. 20037 (202) 457-8400

Fax (202) 457-8411

September 15, 1995

Mr P. R. Barnes

Power Systems Technology Program

Oak Ridge National Laboratories

P.O. Box 2008

Oak Ridge, Tennessee 37831

Dear Mr Barnes:

These comments are submitted on behalf of the members of the Transformer Section of

the National Electrical Manufacturers Association (NEMA) who appreciate the opportunity to

review and comment on the Oak Ridge draft report, "Determination Analysis of Energy

Conservation Standards for Distribution Transformers" (ORNL-6847). The members are

particularly pleased with the accessibilty the ORNL group has provided and the candid exchange

of views relating to the preparation of this report.

After a detailed analysis and discussion of the ORNL report, NEMA members believe,

generally, that while the report reaches the conclusion that the criteria for the determination of

the need for energy efficiency standards has been met, it contains shortcomings in both data

presentation and conceptual posturing that cause its conclusions to be seriously [misleading]

diminished. While technical justification and economic feasibility are presented, it is unclear to

NEMA whether the energy savings are of significant levels to support development of a

standard. In addition, NEMA members believe that the report needs clear enunciation of its

assumptions -- against which to measure its assertions and data - and to sensitize the impact of

these assertions on market and industry realities. Members also have identified a number of less

severe issues and minor comments that, if adopted, would enhance the thoroughness and value

of the study.

Of additional specific concern, members believe that the report's discussion of the

energy savings, the transformer market size, availability of transformer core steel and magnet

wire products and the payback period are so incomplete, and at times inaccurate, as to distort

the issues.

Members believe the report needs to calibrate properly the levels of energy savings as it

relates to total energy consumption. While the report asserts that the savings are significant,

there is a lack of correlation with either total energy consumption or growth. In addition, the

report does not address costs associated with achieving energy savings nor assess the net

impact on the overall system. In fact, it appears that much of the savings are due to the

unsubstantiated significant growth for dry type transformers. We would propose that a sensitivity

analysis, based on the growth rates of both dry- and liquid-type transformers, be pursued.

In the discussion of the transformer market size, we find that first of all, there needs to

be a clear definition of distribution transformer. References within the document variously, and

inconsistently, describe the voltage parameters of distribution transformers. We believe the

distribution transformers should be addressed as follows:

EE-DET-97-550 COMMENT 00C
NEMA Letter -2-

Distribution Transformers

September 15, 1995

Voltage

Class

Primary Voltage

Secondary Voltage

34.5 kV and below

600 volts and below

Liquid

Rating

Single Phase

Three Phase

10 833 kVA

15 - 2500 kVA

Dry

Rating

Single Phase

Three Phase

10 - 833 kVA

15 - 2500 kVA

Additionally, the data in Table 4.7 describes unequal growth rates in the liquid- and dry-type

transformer markets that are not reflective of reality or consistent with industry experiences. It is our

belief that this distortion is caused by the use of consolidated information and data on products

outside of the scope of this study.

While we believe that the payback period applicable to the commercial and industrial market

should not extend beyond three years (for optimal value to the user), we have serious concerns with

the payback discussion, both in terms of its calculations and its reputed savings. It is our view also

that the 2-year payback in Table 4.1 needs additional analysis and discussion because it is based on a

case provided by a single manufacturer.

On the matter of the availability of transformer core steel and magnet wire products, we

believe that the report contains erroneous assertions about the availability of domestic steel products

that are without substantiation and are misleading. The report fails to acknowledge that highest grade

silicon electrical steel is currently no longer available domestically and whatever may be available is

at a substantial premium. Moreover, there are inconsistent references to silicon electrical steel

throughout the report and that clear definitions of "high silicon," "oriented" and "non-oriented" steel

should be defined. In addition, magnet wire is in short supply domestically; further required use

would make the shortfall very real.

The NEMA Transformer Section believes that the aforementioned issues must be addressed

and discussed thoroughly in this report in order to provide the proper framework upon which the key

policy parameters can be fully and completely discussed. Specific comments are provided in

enclosure A. In light of the comments expected from the diverse groups reviewing this draft report,

NEMA recommends that the report be subject to a final peer review before issuance. If you have any

questions, please contact Mr. John Gauthier, transformer industry program manager, at 202-457-8442,

or myself at 202-457-8448.

Sincerely yours,

Kyle Pitsor

Manager, Government Affairs

Enclosure

cc: I. Watson, DoE

EE-DET-97-550 COMMENT 00C
Enclosure A

National Electrical Manufacturers Association

Supplemental Comments to Oak Ridge Report:

"Determination Analysis of Energy Conservation Standards for Distribution Transformers'

As indicated in the cover letter, members of NEMA's Transformer Section have

identified a number of additional less severe issues and minor comments that, if incorporated

into the ORNL Report, would enhance its thoroughness and value.

Page xi "Linsenbardt" is misspelled.

xviii paragraph 1. Reference that "...These "non-evaluated" transformers may have

several times the losses of utility transformers."

This is not correct and not substantiated by any data in the report.

xviii paragraph 2. Liquid-immersed distribution transformers used by utilities account

for 61 BKwHr of annual energy losses.

Does this value of annual KwHr loss include that associated with the 4 million

non-utility units or is it limited to the 40 million utility units cited on page xvii?

Why is there a specific value for losses from utility units but a range for dry type

units?

xix paragraph 1. Reference is made to the Canadian Standard C802 but no report

on its contents is in the report. Why include this reference?

xix paragraph 2. Concludes that significant energy savings can be attained but

there is no quantification.

The statement of significant energy savings should be quantified in absolutes

and percentages.

xix paragraph 3. "...operating at a lower flux density will reduce core losses but

requires more turns of the conductor."

This would be true only if the volts per turn (V/T) were reduced to achieve the

lower induction.

xix paragraph 4. "...dry type transformers offer certain overload, fire, environment

and application advantages for industrial and commercial situations..."

These advantages should be described with respect to the following:

Overload -- ANSI C57.91, ANSI C57.92, ANSI C57.95

Fire -- National Fire Code 1993

Environment -- your choice

Application -- your choice

EE-DET-97-550 COMMENT 00C
PAGE roc paragraph 3. "Savings from conservation would continue to grow with sales of

new transformers. A portion of these savings are already earmarked through

utility purchases of distribution transformers."

A sensitivity analysis would help determine whether or not these savings are

offset by the additional energy requirements necessary to produce the raw

materials needed for construction of the more efficient transformers.

1 paragraph 2. "The high transmission voltages permit lower currents..."

Change permit to result in

1 paragraph 3. Reference to coolants in liquid transformers as fire or other hazard

The use of the fluids is recognized by both the insurance industry and

appropriate standards, including the National Electric Code, that also address

location of both liquid and dry transformers inside buildings.

3 Section 1.2. The reference numbers do not appear to be realistic. If the entire

power center line is converted, would only 2500 units be converted? Where are

all of the other units? Are pad- and pole-mounted transformers being

converted?

Section 2.1 Need for clarity in defining "distribution transformer"

7 Section 2.1.1 Figure 2.2 is misleading in that it depicts saturation at 1.5T.

Modern oriented core steels have much higher saturation levels

14 Section 2.1.3 paragraph 1. Dry type transformers are characterized as

nonflammable.

Since they utilize organic materials, this statement is incorrect. As indicated

above, the NEC places limitations on the application of transformers inside

buildings. The term should be replaced with "fire resistant." The following

sentence should be added : "There are also high firepoint liquid transformers

which may be installed next to buildings or indoors in accordance with the NEC.

Some of these liquids are also environmentally more friendly than oil."

15 Section 2.1.3, paragraph 1, Liquid immersed transformers are characterized as

having unknown environmental effects.

While this may be true , this could also be true for dry type transformers with

respect to end of life considerations.

15 Section 2.1.3, paragraph 2. Dry type transformers are characterized as "truly

nonflammable."

This is incorrect. The dry type transformers permit operation at higher

temperatures and for longer periods than those in liquid immersed units. The

term "fire resistant" should replace the words "truly nonflammable."

A--1

EE-DET-97-550 COMMENT 00C
PAGE 17 Paragraph 1. After the fifth sentence , add the following:

"The increased core volume and weight associated with amorphous cores

requires longer turns of conductor, increasing coil losses."

Paragraph 2. An inaccurate message is stated.

Factually, loss evaluated liquid filled transformers did improve in efficiency to

98.9% or higher. However, non-loss evaluated transformers deteriorated in

efficiency to under 98.0% from the 98.5% level in 1970.

18 Section 2.2, last paragraph. Reference to dry type transformers being

characterized as having "certain overload, fire, environmental and application

advantages..."

These assertions should be well characterized and defined with hard facts.

19 Paragraph 1. In the seventh sentence, change "A generally accepted..." to "An

empirically developed...."

23 Section 3.1, paragraph 1. "...most energy efficient transformers now available

use amorphous cores..."

This assertion is misleading since efficiency is influenced by loading and other

conditions.

Paragraph 1, sentence 3. change parenthetical remark and end of sentence to

read:

"(reducing core losses by 50% of that found in conventional transformers but

costing 20 to 30 % more than energy-efficient silicon steel transformers) .

However, coil losses are the maior component of losses and may increase

compared to conventional desions. These transformers account for about 10%

of new distribution transformer sales (Howe 1993)"

Paragraph 2.

Most liquid immersed transformers in the market segment are three-phase pad

mounted and station-types, not single-phase.

24 The name "Schrieber" is misspelled.

32 Section 3.4.2. statement: "...by contrast, about half of pad-mounted

transformers are evaluated..."

The fact is most are evaluated, as indicated in the table on page D-4 of the

ORNL document.

A--2

EE-DET-97-550 COMMENT 00C
Section 3.4.4

The loading values shown appear to be about right for medium voltage

transformers. Low voltage transformers are about 35% loaded.

33 Section 3.4.4. Statement: "... and reduce losses due to improper loading."

While proper sizing is valuable for a number of reasons, reducing underloading

will not necessarily reduce losses.

37 Section 4.2. The values of $3.50 and $2.25 per watt for no load and load loss,

respectively, are questionable. This concern is especially true when the value of

load losses are considered.

38 Section 4.2, last paragraph, first sentence. Unclear.

Should reference be to "...higher costs associated..."

Section 4.3

The discussion would suggest a requirement for 36 designs (given 3 designs per

rating times 12 ratings). What effort was made to determine the added cost of

features and the role they play in the price of the transformer.?

39 Section 4.4

The discussion of two year payback based on the input of one manufacturer is

inappropriate and not supported by the industry. The sample is too small to be

meaningful.

40 Table 4.2 Recommended revision:

Size

kVA

Average Evaluated Non-evaluated %Eval Base

Liquid NL LL NL LL NL LL

25 Pole 58 312 90 460 85 63 334

50 Pole 103 527 156 640 85 111 544

50 Pad 99 546 150 700 85 107 569

150 Pad 312 1650 450 2100 85 333 1718

750 Pad 1053 5973 1900 8000 85 1180 6277

2000 Pad 2197 14464 3800 18694 60 2838 16156

45 Table 4.4 revise 2000kVA

No Load Losses : -4500; Load Losses: -10780

46 Table 4.5

The values in footnote " b" do not agree with the values in the table.

A--3

EE-DET-97-550 COMMENT 00C
47 Section 4.4.3, last paragraph. "adjustment factor"

The use of this term is unclear and confusing.

57 Paragraph 1.

Change "better quality" to "higher performance"

Paragraph 2

References to the import of M6 grade steel are not broadly applied.

58 Paragraph 3

We believe the cost difference between M2 and M6 steel may be incorrect.

60 Paragraph 1

Delete the last sentence.

61 Section 5.2.1

62 Table 5.1

There needs to be a clarification that the loss savings and paybacks described

are based on comparison to non-evaluated transformers as the reference rather

than the blended base case previously used. Present text could be misleading.

65 - Paragraph 2, sentence 6 ("Liquid.... segment.")

Delete

67 Paragraph 3, sentence 4 ("These non-evaluated... utility transformers.")

Revise to read: "These non-evaluated transformers may have 60-70% higher

losses than utility evaluated transformers."

68 Paragraph 3, sentence 1

Change "better quality" to "higher performance" material.

D-4 Revise table as follows to reflect actual experience

Evaluated Non-evaluated

Liquid 25kVAPole 95 5

50kVA Pole 95 5

50kVA Pole 95 5

Dry, 1 Phase 1 1 99

10 1 99

Dry, 3 Phase 45 Lighting 1 99

D-8 Reference in text to Table D.6. Table not published with report.

EE-DET-97-550 COMMENT 00C