[Federal Register Volume 71, Number 81 (Thursday, April 27, 2006)]
[Rules and Regulations]
[Pages 24972-25008]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-3165]
[[Page 24971]]
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Part III
Department of Energy
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Office of Energy Efficiency and Renewable Energy
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10 CFR Part 431
Energy Conservation Program: Test Procedures for Distribution
Transformers; Final Rule
Federal Register / Vol. 71, No. 81 / Thursday, April 27, 2006 / Rules
and Regulations
[[Page 24972]]
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DEPARTMENT OF ENERGY
Office of Energy Efficiency and Renewable Energy
10 CFR Part 431
[Docket No. EE-TP-98-550]
RIN 1904-AA85
Energy Conservation Program: Test Procedures for Distribution
Transformers
AGENCY: Office of Energy Efficiency and Renewable Energy, Department of
Energy.
ACTION: Final rule.
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SUMMARY: Pursuant to Sections 323(b)(10) and 346(a) of the Energy
Policy and Conservation Act, as amended, (EPCA or the Act), 42 U.S.C.
6293(b)(10) and 6317(a), the Department of Energy (DOE or the
Department) promulgates a rule prescribing test procedures for
measuring the energy efficiency of distribution transformers under
EPCA, definitions to delineate the products covered by the test
procedures, provisions (including a sampling plan) manufacturers must
use to implement the test procedures, provisions to allow manufacturers
to use calculation methods to determine the efficiency of some of their
models, and enforcement testing for distribution transformers. The
Department will use the new test procedures in evaluating what energy
conservation standards are warranted for distribution transformers
other than the low-voltage dry-type. When DOE promulgates such
standards, then the test procedures and other provisions adopted today
will be used to determine the efficiencies and assess compliance of the
transformers subject to these standards. For low-voltage dry-type
distribution transformers, the new standards prescribed for them in
section 325(y) of EPCA, 42 U.S.C. 6295(y), go into effect on January 1,
2007, and all of the provisions of today's rule will become applicable
to those transformers at that time.
EFFECTIVE DATE: This final rule is effective May 30, 2006, except for
Sec. 431.197(a)(4)(i), section 6.2(f) of Appendix A and section 6.2(b)
and (c) of Appendix A which contain information collection requirements
that have not been approved by the Office of Management and Budget
(OMB). The Office of Energy Efficiency and Renewable Energy will
publish a document in the Federal Register announcing the effective
date.
FOR FURTHER INFORMATION CONTACT: Cyrus Nasseri, Project Manager, Test
Procedures for Distribution Transformers, Docket No. EE-TP-98-550,
United States (U.S.) Department of Energy, Energy Efficiency and
Renewable Energy, Building Technologies Program, EE-2J, 1000
Independence Avenue, SW., Washington, DC 20585-0121, (202) 586-9138,
email: [email protected].
Francine Pinto, Esq., U.S. Department of Energy, Office of General
Counsel, GC-72, 1000 Independence Avenue, SW., Washington, DC 20585-
0121, (202) 586-9507, email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Introduction
A. Authority and Background
B. Summary of the Final Rule
II. Discussion
A. General
B. Transformers Subject to the Test Procedure--Definition of
Distribution Transformer
1. General
2. Incorporation and Definition of EPCA's Exclusions--General
3. Specific EPCA Exclusions
a. Transformers with Tap Ranges of 20 Percent or More and
Special Impedance Transformers
b. Testing Transformers
c. Grounding Transformers
4. Other Exclusions Considered
5. Rebuilt or Refurbished Distribution Transformers
6. Coverage of Liquid-Filled Transformers
C. Test Procedure for Distribution Transformers
1. General Discussion
2. Specific Provisions of the Test Procedure
a. Testing Harmonic Transformers
b. Determining Winding Temperatures
c. Test Set Neutrals
d. Losses from Auxiliary Devices
e. Testing of Multiple Voltage Transformers
f. Short-Circuiting Conductor Strap
g. Revisions Suggested by NEMA in TP 2-2005
h. Language Corrections as to Conversion of the Resistance
Measurement to the Reference Temperature and Conducting the No-Load
Loss Test
D. Basic Model
1. General Discussion
2. Definition of a Basic Model
E. Manufacturer's Determination of Efficiency
1. General Discussion
2. Sampling Plan
3. Alternative Efficiency Determination Method (AEDM)
F. Enforcement Procedures
III. Procedural Requirements
A. Review Under Executive Order 12866
B. Review Under the Regulatory Flexibility Act of 1980
C. Review Under the Paperwork Reduction Act
D. Review Under the National Environmental Policy Act of 1969
E. Review Under Executive Order 13132
F. Review Under Executive Order 12988
G. Review Under the Unfunded Mandates Reform Act of 1995
H. Review Under the Treasury and General Government
Appropriations Act of 1999
I. Review Under Executive Order 12630
J. Review Under the Treasury and General Government
Appropriations Act, 2001
K. Review Under Executive Order 13211
L. Review Under Section 32 of the Federal Energy Administration
Act of 1974
M. Congressional Notification
IV. Approval of the Office of the Secretary
I. Introduction
A. Authority and Background
Part C of Title III of the Energy Policy and Conservation Act
(EPCA) provides for an energy conservation program for certain
industrial equipment. (42 U.S.C. 6311-6317) Section 346 of EPCA states
that the Secretary of Energy (Secretary) must prescribe testing
requirements and energy conservation standards for those ``distribution
transformers'' for which the Secretary determines that standards
``would be technologically feasible and economically justified, and
would result in significant energy savings.'' (42 U.S.C. 6317(a)) The
recent amendments to EPCA set forth in the Energy Policy Act of 2005
(EPACT 2005), Pub. L. 109-58, accomplish the following for this
equipment: (1) Section 321(35) of EPCA now defines ``distribution
transformer'' (42 U.S.C. 6291(35)), (2) Section 323(b)(10) of EPCA
provides that the testing requirements ``shall be based on the
`Standard Test Method for Measuring the Energy Consumption of
Distribution Transformers' prescribed by the National Electrical
Manufacturers Association (NEMA TP 2-1998).'' (42 U.S.C.
6293(b)(10)),\1\ and (3) section 325(y) of EPCA prescribes minimum
efficiency levels for low-voltage dry-type distribution transformers
(42 U.S.C. 6295(y)).
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\1\ Section 323(b)(10)(B) also provides that the Department may
``review and revise'' the test procedures established under that
subparagraph. (42 U.S.C. 6293(b)(10)(B))
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On October 22, 1997, the Department issued a notice setting forth
its determination (hereafter referred to as the ``Determination'')
that, based on the best information it had available, energy
conservation standards for electric distribution transformers appeared
to be technologically feasible and economically justified, and were
likely to result in significant energy savings. 62 FR 54809.
The Department subsequently began the process for its issuance of
test procedures for distribution transformers. On February 10, 1998,
the Department held a public workshop (the ``1998 workshop'') to
discuss the following issues: (a) Whether DOE
[[Page 24973]]
should adopt national and international consensus standards as its test
procedures for determining the energy efficiency of distribution
transformers, (b) defining the transformers that the test procedures
will cover, (c) whether, and to what extent, there is a burden on
industry, especially on manufacturers, because of additional testing
and data processing, (d) the definition of ``basic model'' for
distribution transformers, (e) the sampling plan for units to be
tested, (f) the selection of an energy consumption measure for
distribution transformers, (g) the selection of reference temperatures,
(h) the requirements for applying corrections to measurement data, and
(i) the requirements for quality assurance in testing. The Department
also gave interested parties an opportunity to submit written comments
on these issues.
In 1998, the National Electrical Manufacturers Association (NEMA)
published ``NEMA Standards Publication No. TP 2-1998, Standard Test
Method for Measuring the Energy Consumption of Distribution
Transformers,'' (NEMA TP 2-1998) a publication that extracts and
presents pertinent parts of the current industry standards for
distribution transformer efficiency testing. NEMA TP 2-1998 also
presents a weighted average method to compute the energy efficiency of
transformers, in order to demonstrate compliance with the efficiency
levels in NEMA Standard TP 1-1996 (NEMA TP 1).\2\ Comments received at
the 1998 workshop, written comments associated with this workshop, and
NEMA TP 2-1998 formed the basis for preparing the November 12, 1998,
Notice of Proposed Rulemaking (the ``1998 proposed rule'') in this
proceeding. 63 FR 63359.
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\2\ NEMA TP 1 contains suggested efficiency levels. Its full
name and title are ``NEMA Standards Publication No. TP 1-1996, Guide
for Determining Energy Efficiency for Distribution Transformers.''
NEMA TP 1 was updated in 2002, with modifications to some of the
efficiency levels.
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In the 1998 proposed rule, the Department proposed to adopt testing
methods that (1) it could use to evaluate distribution transformers
during the development of efficiency standards, and (2) manufacturers
and DOE would use to determine the efficiency of the transformers which
the standards would cover. DOE proposed to incorporate by reference as
its test methods the provisions from either the Institute of Electrical
and Electronics Engineers (IEEE) Standards C57.12.90-1993 and
C57.12.91-1993 (using IEEE C57.12.00-1993 as an additional reference
source), or NEMA TP 2-1998. The 1998 proposed rule also included
proposed definitions of ``distribution transformer'' and related terms,
of terms used in the test procedure provisions, and of ``basic model.''
It also proposed a sampling plan for applying the test procedures to
perform compliance testing. The sampling approach was based on the plan
for compliance testing in 10 Code of Federal Regulations (CFR) Part
430, which contains energy efficiency requirements for consumer
products, but tailored to distribution transformers and with a minimum
sample size of five units. The Department selected this approach
because it appeared to provide a satisfactory balance between assuring
the accuracy of efficiency ratings for distribution transformers and
minimizing the testing burden on manufacturers. The Department also
sought comment on three alternative compliance approaches for basic
models produced in small numbers.
DOE held a public meeting on January 6, 1999, on the 1998 proposed
rule and received nine written comments. After reviewing the oral and
written comments, DOE concluded that the comments raised a number of
significant issues that required additional analysis. On June 23, 1999,
the Department reopened the comment period on the 1998 proposed rule,
64 FR 33431, (the ``1999 reopening notice'') to provide an opportunity
for additional public comment on the following issues: (a) The
suitability of NEMA TP 2-1998 for adoption as the DOE test procedure;
(b) the adequacy of stakeholder opportunity to review NEMA TP 2-1998;
(c) the transformers covered under the definition of ``distribution
transformer;'' (d) the suitability of the definition of ``basic model''
for the purpose of grouping transformers to limit the test burden; and
(e) the appropriateness of the proposed sampling plan and a number of
alternatives for demonstrating compliance. The Department received five
comments in response to the 1999 reopening notice.
On the basis of these comments, two additional comments it received
subsequently, and its review of the issues raised by the 1998 proposed
rule and the 1999 reopening notice, the Department issued a
supplemental notice of proposed rulemaking (SNOPR). 69 FR 45506 (July
29, 2004). In the SNOPR, DOE proposed to adopt (1) a new ``stand
alone'' test procedure for distribution transformers, drafted by the
Department and consisting almost entirely of test methods contained in
NEMA TP 2-1998 and other existing industry standards, (2) revised
definitions to establish which transformers the test procedure covers,
(3) a new definition of ``basic model'' and a new sampling plan, to
implement the test procedures, (4) provisions to allow manufacturers to
use calculation methods, instead of testing, to determine the
efficiency of some of their models, and (5) enforcement procedures,
including a testing protocol, for distribution transformers. DOE held a
public meeting on September 27, 2004, on the SNOPR (the ``2004 public
meeting'') and received six written comments.
Concurrently with this rulemaking, the Department has evaluated the
establishment of energy conservation standards for distribution
transformers. On October 2, 2000, the Department made available a
Framework Document for Distribution Transformer Energy Conservation
Standards Rulemaking, which was the subject of a public workshop on
November 1, 2000, and on which stakeholders submitted written comments
before and after the workshop. 65 FR 59761 (October 6, 2000).
Thereafter, the Department visited manufacturers of distribution
transformers and posted on DOE's website \3\ several draft reports
concerning the development of standards for these transformers. On the
same day that it published the SNOPR, DOE issued an Advance Notice of
Proposed Rulemaking (ANOPR) for distribution transformer standards. 69
FR 45376 (July 29, 2004). Several of the written comments DOE received
in response to the ANOPR address issues raised in the SNOPR, and the
Department has referenced them in the docket of this rulemaking and has
considered them in formulating today's final rule.
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\3\ http://www.eere.energy.gov/buildings/appliance_standards/commercial/dist_transformers.html
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On October 18, 2005, the Department published a final rule to place
in its regulations the energy conservation standards, and related
definitions, that Congress prescribed in EPACT 2005 for certain
consumer products and commercial and industrial equipment. 70 FR 60407.
The rule included the definitions for ``distribution transformer'' and
``low-voltage dry-type distribution transformer,'' and the standards
for low-voltage dry-type distribution transformers, that were contained
in EPACT 2005. 10 CFR sections 431.192 and 431.196. The Department put
the provisions for all of the commercial and industrial products
covered by EPACT 2005, including those for distribution transformers,
in 10 CFR Part 431. 70 FR 60414-18. In the prior Federal Register
notices dealing
[[Page 24974]]
with test procedures for distribution transformers, DOE had proposed
adding a new part 432 to include requirements for distribution
transformers. 63 FR 63376, 63369; 69 FR 45517, 45520. As a result of
DOE's decision, in response to EPACT 2005, to incorporate provisions
for distribution transformers into 10 CFR Part 431, today's final rule
places the new test procedures for this equipment in Subpart K to 10
CFR Part 431.
B. Summary of the Final Rule
The test procedure in today's rule is based on the test methods
contained in NEMA TP 2-1998 \4\ and IEEE Standards C57.12.90-1999 and
C57.12.91-2001. Initially, the Department will use the test procedure
to evaluate distribution transformers for which it is currently
developing energy conservation standards. When DOE promulgates such
standards, the Department will then require manufacturers to use the
test procedure to determine compliance with the standards and as a
basis for their efficiency representations for covered transformers.
The Department would also use the test procedure in any enforcement
proceeding concerning compliance with such standards and related
labeling requirements. In addition, the test procedures will become
mandatory for all of these purposes--compliance determination,
representations and enforcement--for low-voltage dry-type distribution
transformers when standards go into effect for them, pursuant to 42
U.S.C. 6295(y), on January 1, 2007.
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\4\ In September 2005, NEMA provided the Department with its
revised test procedure document, TP 2-2005, which is similar to the
rule language in the SNOPR. The Department has treated this
submission as a comment on the SNOPR, has incorporated into today's
rule a number of the changes that this revision made to the SNOPR's
rule language, and addressed below the significant differences
between the revision and the SNOPR.
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The language of today's rule sets forth all testing requirements,
without reference to other sources, for determining the energy
efficiency of distribution transformers. Measurement of electric power
consumed by the transformer is in the form of no-load and load losses.
The rule specifies methods with which to measure the temperature,
current, voltage, extent of distortion in voltage waveform, and direct
current resistance of the windings. The rule also prescribes provisions
for calculating efficiency. The testing methods are largely the same as
those proposed in the SNOPR, with several clarifying changes and a few
changes to provide manufacturers with greater flexibility.
Today's rule amends the definition of ``distribution transformer''
that DOE recently adopted, 70 FR 60416, by adding capacity limits (the
same ones the Department proposed in the SNOPR), making minor language
and format changes, and clarifying the exclusion of transformers with
tap ranges greater than 20 percent. As discussed below, today's
definition conforms to, and incorporates the relevant language from,
the definition that EPACT 2005 added to EPCA. (42 U.S.C. 6291(35)) The
Department's definition establishes which transformers the test
procedure covers. It uses the approach DOE proposed in the SNOPR--a
broad definition with numerical criteria, but narrowed by the exclusion
of specific types of transformers, many of which are not commonly
understood to be distribution transformers. The numerical criteria
(except for the added capacity limits) and the exclusions are the same
as those in EPCA's new definition. They include virtually the same
primary and secondary voltage ranges the Department proposed in the
SNOPR, most of the exclusions DOE proposed, and no additional
exclusions. Today's definition of distribution transformer, however,
does not include the exclusions of K-factor and harmonic mitigating
distribution transformers, which DOE proposed in the SNOPR but which
are absent from the EPCA definition. Stakeholders will have the
opportunity in the energy conservation standards rulemaking to comment
to the Department on whether standards should apply to these
transformers.
Today's rule contains several features designed to reduce the
number of transformers that manufacturers would have to test. First,
the Department allows manufacturers to group models into ``basic
models'' for testing purposes, and defines ``basic model'' as proposed
in the SNOPR, with minor clarifications. Second, the rule includes the
same type of compliance sampling plan proposed in the SNOPR, except
that the sampling plan tolerance is based on a single-unit sample
tolerance (confidence limit) of eight percent, rather than the five
percent DOE proposed. And third, today's rule allows manufacturers to
use alternative methods, other than testing, to determine the
efficiency of some basic models. The rule incorporates the SNOPR
proposal except that manufacturers need not use a different method for
each of the following groups of distribution transformers: low-voltage
dry-type, medium-voltage dry-type, and liquid-immersed. Manufacturers
can use a single method for transformers in two or all three of these
groups so long as the method is validated separately in each of the
groups for which the manufacturer uses it. Today's rule also contains
the enforcement procedures proposed in the SNOPR, including a testing
protocol, modified to be consistent with the revised compliance
sampling plan tolerance. Finally, the Department is republishing in
this rule, without substantive change, the standards for low-voltage
dry-type distribution transformers that it originally codified at 70 FR
70417. Today's rule contains a revised table that has a clearer, more
appropriate format than the table in the original rule. The table also
includes the reference conditions for the standards, which DOE
inadvertently omitted from the initial codification but which are
essential elements of the standards, as set forth in Table 4-2 of NEMA
TP 1-2002, from which EPCA incorporates the standards. (42 U.S.C.
6295(y))
II. Discussion
A. General
Representatives of several organizations attended the public
meeting on September 27, 2004, including trade associations (Copper
Development Association, National Electrical Manufacturers Association
(NEMA), and National Rural Electric Cooperative Association),
transformer manufacturers (Acme Electric Corporation (ACME), ERMCO
Distribution Transformers (ERMCO), Federal Pacific Transformer (Federal
Pacific or FPT), Kuhlman Electric Corporation, Pemco Corporation
(Pemco), and Howard Industries, Inc. (Howard Industries or Howard)), a
core steel manufacturer (AK Steel Corporation), electric utility
companies (Georgia Power Company and Ameren Services), the Canadian
Government (Natural Resources Canada), the National Institute of
Standards and Technology (NIST) of the U.S. Department of Commerce, and
private research/consulting entities (BB&F Associates, Lawrence
Berkeley National Laboratory, Merritt and Associates, Navigant
Consulting, Inc., and Optimized Program Services, Inc.). NEMA also
submitted a written statement in advance of the public meeting.
Following the public meeting, ERMCO, Federal Pacific, Howard
Industries, Cooper Power Systems (Cooper) and NEMA each submitted a
written statement. In addition, the Department received ten comments in
its energy conservation standards rulemaking that pertained to both the
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test procedure and the energy conservation standards rulemakings.
Therefore, the Department cross-referenced these comments from the
energy conservation standards docket (EE-RM/STD-00-550) to this
proceeding. The ten cross-referenced comments were submitted by Pemco,
ERMCO, Harmonics Limited, NEMA, Federal Pacific, HVOLT, Inc. (HVOLT),
Oregon Department of Energy (ODOE), Howard Industries, Power Quality
International (PQI) and EMS International Consulting (EMS).
The following summarizes the issues addressed in the preamble of
the SNOPR and discusses in detail the points on which significant
comments were presented during and after the public meeting.
B. Transformers Subject to the Test Procedure--Definition of
Distribution Transformer
1. General
Although EPCA directed DOE to prescribe energy conservation
standards and test procedures for certain ``distribution transformers''
(42 U.S.C. 6317(a)), until recently the Act did not define that term.
Therefore, the Department undertook to adopt such a definition in this
rulemaking. It proposed a definition in the 1998 proposed rule, 63 FR
63362-63, 63369-70, addressed the issue again in the 1999 reopening
notice, 64 FR 33432-34, and proposed a substantially revised definition
in the SNOPR. 69 FR 45506. That revised definition included
transformers meeting numerical criteria as to primary and secondary
voltage and capacity, and excluded specifically listed types of
transformers. 69 FR 45509-10, 45520-22. The Department designed that
definition primarily to (1) encompass within ``distribution
transformer'' only those transformers commonly understood to be
distribution transformers, i.e. those made for the distribution of
electricity, and (2) exclude those distribution transformers for which
standards clearly would not produce significant energy savings. 69 FR
45509-10.
EPACT 2005 recently revised EPCA to include a definition of
``distribution transformer'' (42 U.S.C. 6291(35)), thus filling the gap
DOE had sought to fill with its own definition. As part of the final
rule mentioned above, to place in the CFR certain provisions prescribed
in EPACT 2005, the Department incorporated this new definition, almost
verbatim, into 10 CFR section 431.192. 70 FR 60407, 60416-17. (In the
paragraphs that follow, the new definition is referred to as the
``EPCA'' or ``new'' definition.) The EPCA definition is similar in
approach and content to the definition proposed in the SNOPR. It
includes numerical criteria--a maximum input voltage and frequency that
are similar to those in the SNOPR definition, and a maximum output
voltage that is identical--as well as a list of excluded transformers
that is quite similar to the SNOPR's list of excluded transformers.
(The differences between EPCA's list of exclusions and the SNOPR's list
are discussed below. Today's rule adheres to the EPCA list.) The new
definition also authorizes DOE to add to the list of exclusions any
type of transformer that meets certain criteria.
One significant difference exists, however, between the numerical
criteria in the EPCA and SNOPR definitions. No capacity ranges are
stated in the new definition, whereas the SNOPR definition limits the
term ``distribution transformer'' to liquid immersed units with a
capacity of 10 kVA to 2500 kVA, and dry-type units with a capacity of
15 kVA to 2500 kVA. (The Department has been using a similar definition
to delineate the transformers it is evaluating in the standards
rulemaking. 69 FR 45381-45384.) Transformers outside of these ranges
are not typically used for electricity distribution, which is the
commonly understood function of a distribution transformer. The
Department received no adverse comment on these proposed ranges.
Moreover, NEMA agreed with the proposed lower capacity limit for dry-
type transformers, indicating that efficiency standards for
transformers with lower kVA ratings would fail to meet the criteria in
section 346 of EPCA. (NEMA, No. 39 at p. 2; Public Meeting Transcript,
No. 42.11 at p. 22) \5\ But notwithstanding the lack of any explicit
capacity limits in the EPCA definition of distribution transformer, as
a practical matter an upper capacity limit is implicit in that
definition. A transformer's capacity is to some extent tied to its
primary (input) and secondary (output) voltages. Therefore, the maximum
limits for primary and secondary voltages, of 34.5 kilovolts and 600
volts, respectively, in the EPCA definition have the practical effect
of limiting transformers that meet the definition to those with a
maximum capacity in the range of approximately 3750 to 5000 kVA, or
possibly slightly higher. The voltage limits in the EPCA definition,
however, subsume no lower limit on capacity.
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\5\ A notation in the form ``NEMA, No. 39 at p. 2'' identifies a
written comment the Department has received and has included in the
docket of this rulemaking. This particular notation refers to a
comment (1) by the National Electrical Manufacturers Association
(NEMA), (2) in document number 39 in the docket of this rulemaking
(maintained in the Resource Room of the Building Technologies
Program), and (3) appearing on page 2 of document number 39.
Likewise, ``Public Meeting Transcript, No. 42.11 at p. 22,'' for
example, would refer to page 22 of the transcript of the ``Public
Meeting on Test Procedures for Distribution Transformers'' held in
Washington, DC, September 27, 2005, which is document number 42.11
in the docket of this rulemaking.
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It is unclear whether ``distribution transformer'' as now defined
in EPCA and DOE's regulations is, or can be, subject to capacity ranges
other than the just-mentioned upper limit. On the one hand, the new
definition includes no such capacity limitation, and it authorizes DOE
to exclude from the definition, by rule, any transformer if it is
designed for a special application, is unlikely to be used in a general
purpose application, and significant energy savings would not result
from applying standards to it. (42 U.S.C. 6291(35)(B)(iii)) This
suggests that unless, and until, DOE acts and identifies capacity
ranges that meet these criteria, they are not part of the new
definition of distribution transformer. On the other hand, it is
uncertain whether Congress intended to regulate as distribution
transformers units outside of the capacity ranges in the SNOPR, because
few are used to distribute electricity. In addition, at the same time
it enacted the new distribution transformer definition, Congress also
directed use of, and incorporated into EPCA, provisions of NEMA TP 2-
1998 and NEMA TP 1-2002, respectively (42 U.S.C. 6293(b)(10) and
6295(y)), both of which apply only to transformers with capacity ranges
similar to those in the SNOPR definition. Thus, Congress may have
intended to limit the term ``distribution transformer'' to transformers
within the capacity ranges that normally characterize transformers that
distribute electricity. If so, that would mean the Department's
authority to regulate the efficiency of transformers under 42 U.S.C.
6317 would be limited to transformers within these capacity ranges.
Given the inclusive language of EPCA's definition of distribution
transformer, however, the Department is not prepared at this point to
infer that EPCA imposes this limitation. The Department also does not
possess information on whether transformers outside of these ranges
would meet the criteria in 42 U.S.C. 6291(35)(B)(iii), particularly the
one on energy savings from applying standards, for exclusion from the
definition of distribution transformer. The standards rulemaking
[[Page 24976]]
for distribution transformers, in which DOE would develop such
information, and this test procedure rulemaking to a slightly lesser
extent, have focused almost entirely on transformers within the
capacity ranges. Thus, at the present time, DOE is proceeding on the
premise that ``distribution transformer'' as defined in EPCA includes
transformers outside the capacity ranges in the SNOPR.
One option, therefore, would be for the Department to retain this
definition in its rules, not revise it in today's rule, and apply it in
any standards rulemaking as well. That would have little or no impact
on adoption of the test procedures in today's rule, but it might delay
issuance of the rule. The Department believes that the test procedures
as proposed in the SNOPR and revised for inclusion in today's rule
would be valid for determining the efficiency of transformers with
capacities up to the limits implicit in EPCA's definition, and below
the lower end of the proposed ranges proposed in the SNOPR.
Nevertheless, because DOE had not proposed to apply the test procedure
to transformers with such capacities, it would have to provide some
opportunity for public comment on the applicability of the test
procedure to those transformers. Doing so could delay completion of
this rulemaking.
The impact in the standards rulemaking, of applying the EPCA
definition without capacity limits, would be much greater than the
impact of doing so in this test procedure rulemaking. Formulating
standards for a product involves developing an understanding of, and
evaluating, factors such as the nature of the product, its market, the
technical feasibility of potential efficiency improvements, the
manufacturing costs of such improvements, the resulting energy savings,
the cost of the improved product(s) to purchasers, the impact of
efficiency standards on manufacturers and utilities, and environmental
and employment impacts, as well as other factors unique to a particular
product. The Department has been engaged in such activities with
respect to distribution transformers for over five years, examining for
the most part products within the capacity ranges in the SNOPR
definition of distribution transformer. It is now developing proposed
standards for these products. To expand that rulemaking now to include
transformers outside these ranges would impose a substantial burden on
DOE, and would substantially delay the rulemaking by requiring that the
Department go back to the beginning of the process of evaluating
standards for these additional transformers. Neither DOE nor
stakeholders contemplated that the standards rulemaking would cover
these additional transformers. To the contrary, as indicated above,
interested parties had reached a consensus as to the transformers to be
covered in the standards rulemaking, and expect that DOE will now move
as promptly as possible to promulgate standards for these transformers.
Another possibility would be for the Department to attempt to
preserve the current scope of the standards and test procedure
rulemakings by pursuing exclusion from the definition of distribution
transformer, under 42 U.S.C. 6291(35)(B)(iii), of transformers with
capacities outside the ranges specified in the SNOPR definition. This
too would delay the rulemakings. For DOE to gather relevant information
and assess whether transformers above and below the SNOPR's capacity
ranges meet the criteria in 42 U.S.C. 6291(35)(B)(iii), would be
burdensome and time consuming. And if DOE determined exclusion of these
transformers to be warranted, it would have to undertake additional
rulemaking proceedings to achieve such exclusion. Moreover, if DOE were
to conclude that these transformers do not meet the criteria for
exclusion, DOE would be in essentially the same position it is in now.
The Department is determined to avoid further delays in the
rulemakings on standards and test procedures for distribution
transformers. Therefore, it does not wish either to expand these
rulemakings to cover transformers outside the SNOPR's capacity ranges,
or to pursue at this time exclusion of such transformers from the
definition of distribution transformer. Furthermore, the transformers
within these capacity ranges clearly are within the new EPCA definition
of distribution transformer, so the Department is authorized to pursue
standards for them, and DOE believes there are ample grounds to
conclude that such standards are warranted under the criteria of
section 346(a) of EPCA, 42 U.S.C. 6317(a).
For these reasons, Sec. 431.192 of today's final rule modifies the
EPCA definition of distribution transformer that was recently
incorporated into the DOE rules by adding to it the kVA capacity
limitations in the SNOPR definition. This definition will not include,
as it could not, any transformers excluded from the EPCA definition,
and today's test procedure and any standards rulemaking will not cover
such transformers. The Department is adopting this definition, with its
capacity limitations, for the purpose of delineating the coverage of
today's rule, as well as the transformers that will be evaluated in the
current standards rulemaking for distribution transformers. The
inclusion of the capacity limitations in today's definition does not
mean that DOE has concluded that the EPCA definition of distribution
transformer includes such limitations. Rather, at some point after
completion of the current rulemakings as to distribution transformers,
the Department intends to evaluate transformers with larger and smaller
capacities than those included in today's definition, review how EPCA
should be construed with regard to those transformers, and decide what
if any action to take with regard to adoption of efficiency
requirements for such transformers. If DOE adopts efficiency
requirements for any of these transformers, it would amend the
definition of ``distribution transformer'' in its regulations
accordingly.
Finally, the capacity limitations in today's definition of
``distribution transformer'' will have no effect on the existing
requirements for low-voltage dry-type distribution transformers. EPCA
sets forth a definition and standards for this equipment, 42 U.S.C.
6291(38) and 6295(y), which DOE incorporated into its regulations at 10
CFR sections 431.192 and 431.196(a). Because the definition states that
a ``low-voltage dry-type distribution transformer'' is a ``distribution
transformer'' that meets certain criteria, the addition of capacity
limits to the definition of ``distribution transformer'' could be read
as affecting what constitutes a ``low-voltage dry-type distribution
transformer'' under the regulation. As stated above, however, the
maximum limits for primary and secondary voltages of 34.5 kilovolts and
600 volts, respectively, in EPCA's definition of ``distribution
transformer,'' in effect limit transformers that meet that definition
to those with a maximum capacity of approximately 3750 to 5000 kVA.
Similarly, one of the criteria for a ``low-voltage dry-type
distribution transformer'' is that its primary voltage not exceed 600
volts, 10 CFR section 431.192, which contemplates a secondary voltage
much lower than 600 volts. The obvious effect of this is that a
transformer will be a ``low-voltage dry-type distribution transformer''
under the regulations only if its maximum capacity is far less than
3750 kVA, and in all likelihood less than the 2500 kVA maximum in
today's definition of distribution transformer. In addition,
[[Page 24977]]
EPCA and DOE rules prescribe standards for low-voltage dry-type
distribution transformers only with kVA's within the range of 15 to
1000, 42 U.S.C. 6295(y) and 10 CFR section 431.196(a), which are within
the 15 to 2500 kVA range that today's definition of ``distribution
transformer'' incorporates for dry-type transformers. For these
reasons, the capacity limitation in today's definition of
``distribution transformer'' has no impact on the current DOE and EPCA
requirements for low-voltage dry-type distribution transformers.
2. Incorporation and Definition of EPCA's Exclusions--General
As indicated above, DOE incorporated into its rules the new EPCA
definition of distribution transformer, including the language listing
specific types of excluded transformers and authorizing DOE to add to
that list. 70 FR 60416-17. Upon further review, the Department has
decided to adopt in Section 431.192 of today's rule several editorial,
clarifying and format changes to the language concerning the
exclusions.
To begin with, this language states that the term ``distribution
transformer'' does not include ``a transformer that is designed to be
used in a special purpose application and is unlikely to be used in
general purpose applications, such as [the list of specifically
excluded transformers]'' (42 U.S.C. 6291(35)(B)(ii); 70 FR 60416-17) At
first reading, this language appears to exclude unspecified types of
transformers that meet the criteria just quoted, and to introduce a
list consisting of specific illustrations of the transformers excluded.
However, the very next paragraph of the definition states that DOE may,
``by rule,'' exclude ``any transformer not listed'' which meets
criteria that, in substantial part, are virtually identical to the
criteria just quoted. (42 U.S.C. 6291(35)(B)(iii); 70 FR 60416) If the
definition were read as excluding any transformer, in addition to those
specifically listed, that met these criteria, this would obviate and
render null the provision authorizing DOE to exclude additional
transformers that meet these criteria, but only through rulemaking. The
Department believes, however, that the soundest construction of these
provisions is that transformers not specifically listed in the
definition can be excluded only through a DOE rulemaking, thus
providing certainty as to which transformers are covered at any given
point in time. Use of the language quoted at the beginning of this
paragraph to introduce the list of specifically excluded transformers
serves to describe those transformers, and helps indicate the types of
transformers the statute authorizes DOE to exclude by rule. Therefore,
because this provision does not actually delineate excluded
transformers, and in order to avoid confusion as to the function of
this language, DOE in today's rule has amended section 431.192 by
excluding it.
As just indicated, DOE incorporated into its definition of
distribution transformer language from EPCA that authorizes DOE to add
to the list of excluded transformers. (42 U.S.C. 62912(35)(B)(iii); 70
FR 60416-17) Because this language authorizes action by DOE and does
not actually describe transformers that are not ``distribution
transformers,'' upon further reflection the Department believes that
the language need not be included in the definition in the DOE rules.
Therefore, the Department has amended its definition of ``distribution
transformer'' by omitting this language from section 431.92 of today's
rule.
As to the specific exclusions, the Department indicated when it
adopted the EPCA definition, 70 FR 60408, that the definition uses
incorrect terms in its exclusions of ``Uninterruptible Power System
[UPS] transformer, impedance transformer, * * * [and] sealed and
nonventilating transformer.'' (42 U.S.C. 6291(35)(B)(ii)) In accordance
with its expressed intention to address such minor drafting problems in
future rulemaking proceedings, where Congress has not already done so,
70 FR 60408, in today's rule DOE is amending its definition of
distribution transformer to correct use of these terms. First, UPS
transformers are commonly referred to as ``Uninterruptible Power Supply
transformers,'' not ``Uninterruptible Power System transformers,'' and
therefore DOE adopts the former term in today's rule. Second, every
transformer has an impedance, but only transformers with impedances
outside of normal ranges, i.e., ``special-impedance'' transformers,
warrant exclusion from standards. The Department had proposed to
exclude such transformers from its definition of distribution
transformer in the SNOPR, and NEMA excludes them from coverage of NEMA
TP 1 and TP 2. Therefore, DOE construes EPCA as excluding ``special
impedance'' transformers, and today's rule substitutes that term for
``impedance'' in the list of exclusions. Third, IEEE standards define
``sealed'' transformers separately from ``nonventilated'' transformers,
treating them as two different types of transformers. The definitions
are such that it would be highly unlikely for a particular transformer
to be both ``sealed'' and ``nonventilated.'' In the SNOPR, DOE treated
them as two separate exclusions from the term ``distribution
transformer,'' as it believes is appropriate. In light of the
foregoing, DOE construes EPCA as containing separate exclusions for
sealed and nonventilated transformers, and today's rule so provides.
The Department has also changed the format for the specific
exclusions in section 431.192 of today's rule, and adopted the approach
in the SNOPR, by placing the exclusions in a numbered list, rather than
simply listing them seriatim in a single paragraph. The Department
believes this will make the rule easier to read and use.
Finally, conforming to the approach in EPCA, DOE's recently adopted
rule lists the 12 types of transformers it excludes from the term
``distribution transformer,'' but contains no definition for any of
them. 70 FR 60416-17. In the SNOPR, DOE proposed definitions for the
transformers it proposed to exclude. The Department believes such
definitions are warranted because they help to clarify exactly which
transformers are covered. Today's rule includes seven definitions drawn
from IEEE standards, and five that DOE developed based on industry
catalogues, practice and nomenclature. DOE believes they represent a
reasonable construction of the EPCA exclusions. Except as indicated in
the discussion below of the definitions of special impedance, testing
and grounding transformers, they are the same definitions DOE proposed
in the SNOPR.
3. Specific EPCA Exclusions
a. Transformers With Tap Ranges of 20 Percent or More and Special
Impedance Transformers
EPCA and the Department's recently adopted rule exclude from the
definition of ``distribution transformer'' transformers with ``multiple
voltage taps, the highest of which equals at least 20 percent more than
the lowest.'' 42 U.S.C. 6291(35)(B)(i); 70 FR 60416. The Department
reads this language as excluding transformers with a tap range of 20
percent or more. It is similar to the exclusion in the SNOPR of
transformers with a tap range greater than 15 percent. The language
EPCA uses for this exclusion, however, is ambiguous.
Each distribution transformer with multiple voltage taps has a
nominal voltage at which it normally operates and other voltages
(taps), typically
[[Page 24978]]
above and below its nominal voltage at which it can also operate. The
voltage taps enable the transformer to be connected to distribution
lines at these other voltages. The tap range represents the difference
between the highest and lowest voltage taps relative to the nominal
voltage, expressed as a percentage. It is unclear whether, under the
EPCA exclusion, a transformer's tap range is determined by computing
the percentage of the voltage difference between its lowest and highest
voltage taps relative to the voltage of the lower tap, or, as the
industry has traditionally done, by adding the sum of the percentages
by which the highest and the lowest voltage taps deviate from the
nominal voltage. (The traditional industry method is equivalent to the
percentage of the difference between the lowest and highest voltage
taps relative to the nominal voltage.) These two approaches generally
yield two different results for tap range value for any given
transformer with multiple voltage taps. For example, a 600-volt primary
transformer with two 2.5-percent taps above and four 2.5-percent taps
below the nominal, with the highest tap being 630 volts and the lowest
540 volts, would normally be referred to as having a tap range of 15
percent (i.e., 6 times 2.5 percent, or 90 volts as a percentage of 600
volts = 15 percent). Similarly, a 600-volt primary with three 2.5-
percent taps above and three 2.5-percent taps below the nominal, with
the highest tap being 645 volts and the lowest 555 volts, would also be
referred to under the traditional industry approach as having a tap
range of 15 percent. However, if the tap percentages for these
transformers were calculated as a percentage of the voltage rating of
the lowest tap (540 volts and 555 volts in these examples), these two
transformers would have a tap range of 16.2 percent and a 16.7 percent,
respectively.
The Department believes that EPCA's exclusion of transformers with
a tap range of 20 percent or more is best construed as reflecting
standard industry practice, such that tap ranges do not vary with the
voltage rating of the lowest tap. Rather, tap range should be
calculated, and excluded transformers identified, based on the industry
practice of calculating the transformer's percent tap range relative to
the nominal voltage of the transformer. Accordingly, the Department
interprets EPCA as excluding transformers from the definition of
``distribution transformer'' when the aggregate of the transformer's
highest to lowest tap voltages, relative to the nominal voltage, equals
at least 20 percent. In section 431.192 of today's rule, the Department
has incorporated this interpretation into its regulations by adding
clarifying language to amend the regulation containing this exclusion
that it adapted from EPCA in 70 FR 60416.
The Department also notes that EPCA includes this exclusion in a
separate paragraph, rather than in the list that comprises the other
exclusions from the definition of ``distribution transformer.'' (42
U.S.C. 6291(35)(B)(i)-(ii)) See 70 FR 60416. To present this exclusion
in the same format as the other exclusions, in section 431.192 of
today's rule the Department has added ``Transformer with Tap Range of
20 percent or more'' to the list of exclusions and defined that term
using the EPCA language that contains the exclusion, modified as just
indicated.
As indicated above, the Department had proposed in the SNOPR to
exclude transformers with tap ranges greater than 15 percent. 69 FR
45110, 45420-22. Pemco, a manufacturer, expressed the concern that, if
the Department declines to adopt efficiency standards for distribution
transformers with a tap range of greater than 15 percent (currently the
standard tap range for low voltage dry-type transformers),
manufacturers might begin producing transformers with a slightly larger
tap range, and such transformers would not be covered by standards.
(Pemco, No. 48 at p. 2) That could create a significant loophole under
the regulations. Since the 20-percent tap range is larger than the
previously proposed 15-percent range, exclusion of transformers with
tap ranges of at least 20 percent should reduce the risk that
transformers with slightly larger tap ranges would be produced in order
to avoid coverage. But that risk will not be completely eliminated.
The exclusion of special impedance transformers, as provided in
EPCA, as recently incorporated by DOE into 10 CFR section 431.192, and
as previously proposed by DOE in the SNOPR, raises a similar issue. The
issue is brought into focus by DOE's proposed definition for these
transformers in the SNOPR. The proposed definition specified a normal
impedance range for each standard kVA rating, and stated that a
``special-impedance transformer'' would be any transformer with an
impedance outside the applicable range. Any such transformer would not
be a ``distribution transformer'' covered by the proposed rule. 69 FR
45510-11, 45520-22. No commenter objected to this exclusion, and only
one specifically addressed it. Howard Industries recommends that DOE
replace its proposed normal impedance ranges with ranges included in
Howard's comments, which are more in line with ranges ANSI uses to
delineate special impedance transformers and on which most utility
systems are based. (Howard, No. 55 at p. 3) For most kVA levels, DOE's
proposed ranges are broader than Howard's. Hence, DOE's ranges would
result in exclusion of fewer transformers, by classifying fewer as
``special impedance.'' In its revised test procedure document, NEMA TP
2-2005, NEMA incorporated DOE's proposed normal impedance ranges.
(NEMA, No. 60 Attachment 1 at pp. 5-6)
The Department is concerned that some transformers designed for
electricity distribution could be manufactured with impedances outside
normal ranges so that they would not be subject to otherwise applicable
efficiency standards. Such transformers could be less expensive to
manufacture than normal impedance transformers manufactured in
compliance with the standards, and therefore could have a competitive
advantage over standards-compliant distribution transformers. If this
occurred, it would subvert the standards. At best, the manufacturer(s)
of such new, non-complying transformers would sell them in place of
complying products they would otherwise have sold, and the product
would have a share of the market for which DOE analysis demonstrated
that standards were technologically feasible and economically
justified. This would reduce energy savings below the levels that
standards under EPCA are designed to achieve, and reduce the benefits
transformer consumers and the public would realize from the standards.
At worst, to avoid significant losses of market share to the competing,
non-complying transformer, other manufacturers would be forced to
produce the same type of non-complying unit. In that case, all or most
of the benefit of standards could be lost.
The Department believes that use of the impedance ranges in the
proposed rule, to delineate special impedance transformers, is a
reasonable implementation of EPCA's exclusion of these transformers.
This is the same approach, discussed above, that EPCA follows in its
exclusion of transformers with non-standard tap ranges, in that only
transformers that are considerably outside the normal ranges are
excluded from coverage. To construe EPCA otherwise, that is, to
construe it as excluding from coverage any transformer that falls
outside the current, standard normal impedance ranges, could spawn a
new generation of distribution transformers with impedances outside
these ranges, which
[[Page 24979]]
would not be subject to Federal efficiency standards and test
procedures. As just mentioned, this could subvert DOE's energy
efficiency standards. NEMA's inclusion of DOE's proposed impedance
ranges in the revised TP 2 standard provided to the Department, and the
fact that only one commenter objected to them, indicate they are a
sound basis for delineating the special impedance transformers that are
excluded from coverage under today's rule and DOE's efficiency
standards. Therefore, section 431.192 of today's rule retains the
SNOPR's proposed definition of the ``special-impedance transformers''
excluded from the term ``distribution transformer.''
The Department recognizes that this approach may not prevent
attempts to circumvent its efficiency requirements through manufacture
of distribution transformers that appear to, or do, fall just within
this exclusion or the exclusion of transformers with tap ranges of 20
percent or more. Such transformers could conceivably be manufactured
for use in standard applications to distribute electricity in power
distribution systems, but with efficiencies below those required by
DOE's standards. Indeed, other exclusions from today's definition of
distribution transformer could also be exploited to justify manufacture
of transformers, for standard distribution applications, that do not
meet DOE standards. The Department believes one such example may be the
exclusion for drive (isolation) transformers. Such transformers can be
similar to standard distribution transformers. A manufacturer might be
able to produce and market, for standard distribution uses, a
transformer that does not meet DOE efficiency standards but that
clearly, or arguably meets, DOE's definition of ``drive (isolation)
transformer,'' and claim that it is not a ``distribution transformer''
as defined by DOE.
The Department intends to strictly and narrowly construe the
exclusions from the definition of ``distribution transformer.'' It will
also take appropriate steps, including enforcement action if necessary,
if any manufacturer or other party erroneously invokes one of the
exclusions as a basis for marketing a transformer that is a
``distribution transformer'' under today's rule but does not meet DOE
standards. Moreover, to the extent transformers that do fall within the
exclusions begin to be marketed for standard distribution applications,
or find widespread use in such applications, DOE will examine whether
re-defining the relevant exclusions, and/or legislative action, is
warranted.
b. Testing Transformers
EPCA, and DOE's recent rule, also exclude a ``testing transformer''
from the definition of distribution transformer, 42 U.S.C.
6291(35)(B)(ii) and 70 FR 60416, as does section 431.192 of today's
rule. The Department proposed this exclusion in the SNOPR. 63 FR 63363;
69 FR 45510. No stakeholder commented on it, in response to either the
NOPR or SNOPR, except that in its revised TP 2-2005 document, NEMA
deleted the following sentence from the SNOPR's proposed definition of
``testing transformer'': ``This type of transformer is also commonly
known as an Instrument Transformer.'' (NEMA, No. 60 Attachment 1 at p.
7) An instrument transformer, however, is a type of transformer used
for extending the voltage and current ranges of measuring and control
instruments--such as voltmeters, ammeters, wattmeters, and relays--and
is not the same as a testing transformer that supplies power to test
electrical equipment. The Department recognizes that it erroneously
included this sentence in the SNOPR definition of testing transformer
and has deleted it from today's rule.
The Department believes that this error would not have lead
stakeholders to infer that DOE had proposed to specifically exclude
instrument transformers from the definition of ``distribution
transformer'' in the SNOPR, for two reasons. First, the remainder of
the proposed definition of testing transformer clearly did not include
instrument transformers, and second, contrary to the incorrect
sentence, testing transformers are not commonly known as instrument
transformers. Nevertheless, to the extent the proposed rule may have
been read to specifically exclude instrument transformers, DOE believes
such an exclusion is unnecessary and unwarranted. The revised NEMA TP
2-2005 contains no such exclusion. Moreover, an instrument transformer
would be designed to handle less power than the lower capacity limits
(10 kVA for liquid-immersed and 15 kVA for dry-type) in today's
definition of distribution transformer, unless it was also designed to
distribute electricity. In the former case, the transformer would not
be covered under today's rule (or under the SNOPR) even absent a
specific exclusion, rendering an exclusion unnecessary. In the latter
case, it should be covered, and subject to DOE efficiency standards and
test procedures, as a ``distribution transformer.'' Hence, there is no
reason to consider further the exclusion of ``instrument transformers''
from today's definition of distribution transformer.
c. Grounding Transformers
Finally, section 431.192 of today's final rule contains a
clarifying modification to the SNOPR's definition of ``grounding
transformer.'' That definition referred to ``[a]n autotransformer with
a zig-zag winding arrangement.'' 69 FR 45521. The Department has since
become aware that this language is internally inconsistent, because an
autotransformer with a zig-zag winding cannot be an autotransformer as
defined in the rule, nor does it meet industry's conventional
understanding of the term. The Department used the term autotransformer
in the proposed grounding transformer definition to describe a type of
transformer that does not have a separate physical secondary winding
(unlike a conventional transformer). But although a three-phase
autotransformer has three coils constituting the primary winding only,
and no separate secondary winding, a section of each primary coil is
``tapped-off'' to create, in effect, a secondary winding. A grounding
transformer, however, has only a primary winding, and no secondary
winding output. In today's rule, in the definition of ``grounding
transformer,'' the Department has replaced the reference to an
autotransformer with a reference to a transformer with a primary
winding and no secondary winding.
4. Other Exclusions Considered
The bulk of the comments on the SNOPR's definition of distribution
transformer advocated eliminating or narrowing exclusions DOE had
proposed, or adding other exclusions. EPACT 2005 incorporated none of
these exclusions into EPCA.
In the SNOPR, DOE had proposed to exclude both harmonic mitigating
transformers and K-factor (also referred to as ``harmonic tolerating'')
transformers at K-13 and higher, largely based on its view that: (1)
regulating them would not save significant amounts of energy, and (2)
they are sufficiently expensive that there is little risk they would be
purchased in place of more efficient transformers that would be subject
to standards. 69 FR 45511, 45520-21. The Department also indicated its
belief that few harmonic mitigating transformers would be commonly
understood to be distribution transformers. 69 FR 45511. No commenter
advocated retention of either exclusion, and several supported
eliminating or narrowing them.
[[Page 24980]]
Supporting elimination of both exclusions, NEMA stated that the
exclusions could be used to avoid efficiency standards. (NEMA, No. 39
at p. 2 and No. 47 at p. 2; Public Meeting Transcript, No. 42.11 at p.
22; NEMA No. 51 at p. 2) The Oregon Department of Energy raised doubts
that these transformers would be unable to meet standards and saw no
rationale for excluding them. (ODOE, No. 54 at p. 2) Harmonics Limited
believes the market for them is large and growing, that use of K-rated
transformers to circumvent existing standards has resulted in greater
energy consumption, and harmonic transformers can both comply with
standards and address harmonics issues. (Harmonics Limited, No. 50 at
p. 1) ACME and Pemco advocated elimination of the exclusion for K-
factor transformers (Public Meeting Transcript, No. 42.11 at pp. 32-33;
Pemco, No. 48 at p. 2), and EMS International Consulting, Inc. (EMS)
advocated elimination of the exclusion for harmonic mitigating
transformers. (EMS, No. 57 at p. 3) In addition, EMS recommended that
DOE cover K-rated transformers (up to a certain level which EMS did not
specify), and Federal Pacific recommended narrowing the K-factor
exclusion for transformers rated up to 300 kVA and broadening it for
transformers above 300 kVA, both on grounds similar to those advanced
by commenters who advocated its elimination. (EMS, No. 57 at p. 2; FPT,
No. 44 at pp. 2-3 and No. 52 at p. 2)
Based on these comments, and upon further review, DOE has concluded
there is not a sufficient basis at this point to exclude harmonic
mitigating or K-factor transformers from the definition of distribution
transformer. In essence, the Department proposed in the SNOPR to
exclude these transformers on the grounds that they are not
``distribution transformers,'' and that energy conservation standards
for them would fail to meet the EPCA criteria in 42 U.S.C. 6317(a)(1)
because such standards would not save substantial amounts of energy
and/or be economically justified. Concerning the first point, as
discussed above, EPCA, as amended in EPACT 2005, now defines the term
``distribution transformer.'' Harmonic mitigating and K-factor
transformers do not per se fail to meet the numerical criteria in this
definition, nor are they in the definition's list of excluded
transformers. (42 U.S.C. 6291(35)(A) and (B)(i)-(ii))
EPCA, as recently amended, now authorizes DOE, however, to exclude
by rule any transformer if it is designed for a special application, if
it is unlikely to be used in a general purpose application, and if
significant energy savings would not result from applying standards to
it. (42 U.S.C. 6291(35)(B)(iii)) DOE previously relied on general
information to support the views expressed in the SNOPR that harmonic
mitigating and K-factor transformers would not be used for general
purpose distribution applications, and that standards for them would
not save significant amounts of energy. However, these conclusions were
somewhat negated by the comments that these transformers could be sold
in place of distribution transformers that are subject to standards,
and that their use is increasingly common. Also, the Department is not
aware of any more concrete information or analyses that address whether
standards for these transformers could save energy. Thus, the
Department now has no basis for excluding them under the new criteria
in section 42 U.S.C. 6291(35)(B)(iii). For these reasons, DOE cannot
conclude at this point that harmonic mitigating or K-factor
transformers fail to meet the new EPCA definition of ``distribution
transformer.''
Concerning the issue of whether these transformers should be
excluded from DOE's definition of distribution transformer on the
ground that energy conservation standards for them would not meet the
criteria in 42 U.S.C. 6317(a)(1), as just set forth, there is
insufficient basis to conclude that such standards would fail to save
substantial amounts of energy. Furthermore, comments that harmonic
mitigating and K-factor transformers could be manufactured to be in
compliance with applicable efficiency standards without excessive cost
suggest that standards for this equipment might well be economically
justified. As with the issue of potential energy savings, the
Department is not aware of any concrete information or analyses that
suggest that standards for K-factor and harmonic mitigating
transformers are not economically justified. Thus, the Department
believes there is insufficient basis to conclude at this point that
standards for these transformers would fail to meet the criteria in 42
U.S.C. 6317(a)(1).
Some commenters suggest adding other exclusions to the definition
of distribution transformer. Federal Pacific recommends that mining
transformers (transformers installed inside a mine, inside equipment
operated in a mine, or as a component of underground-digging or
tunneling machinery) be excluded from the application of standards,
because of their radically different loss characteristics and special
dimensional constraints. (FPT, No. 52 at p. 2) Aligning with that
comment, NEMA excludes mining transformers from its revised test
procedure, TP 2-2005. (NEMA, No. 60, Attachment 1 at p. 1 and p. 4)
Pemco asserts the need for an exclusion for transformers subject to
dimensional, physical or design constraints, such as height limits, low
temperature rise, special sound level requirements, weight limits, and
suitability for high altitudes, which, according to Pemco, render it
physically impossible or cost-prohibitive for these transformers to
meet an efficiency standard. (Pemco, No. 48 at p. 1) Pemco also states
that an exclusion is needed for retrofit transformers that have to be
exactly the same as the ones they are replacing. (Pemco, No. 48 at p.
1-2) Similarly, Howard Industries advocates an exclusion for retrofit
transformers, particularly underground and subway style transformers,
on the grounds that they are subject to severe physical or electrical
constraints, and would be unable to also meet energy conservation
standards. (Public Meeting Transcript, No. 42.11 at p. 36; Howard, No.
55 at p. 3) However, although NEMA views the lack of an exclusion for
retrofit transformers as problematic, it did not advocate such an
exclusion because it has not formulated a definition or solution for
this problem. (Public Meeting Transcript, No. 42.11 at p. 35)
In the SNOPR, DOE did not propose to exclude any of the foregoing
types of transformers from its proposed definition of distribution
transformer. And as with K-factor and harmonic mitigating transformers,
EPCA excludes none of them from its definition of distribution
transformer. (42 U.S.C. 6291(35)(A) and (B)(i)-(ii)) Furthermore, the
commenters who supported these additional exclusions have provided
neither data as to the energy savings potential of standards for these
transformers, nor information as to the likelihood they could be used
in general purpose applications, and the Department is not aware of any
concrete information or analyses that address these points. Therefore,
the Department has no basis for excluding any of the transformers
discussed in this paragraph under section 321(35)(B)(iii) of EPCA. (42
U.S.C. 6291(35)(B)(iii)) As to whether these transformers satisfy the
criteria in 42 U.S.C. 6317(a)(1) for adopting test procedures and
standards, the commenters have provided broad claims, but no technical
or factual evidence, that addresses this issue.
For these reasons, the Department has concluded that there is not a
sufficient basis at this point to exclude harmonic mitigating or K-
factor transformers, or
[[Page 24981]]
transformers subject to dimensional, physical or design constraints
(including mining transformers), from today's definition of
distribution transformer, and the definition does not exclude them.
Rather, DOE will revisit the issues of whether, and to what extent,
these transformers should be subject to standards, and at what levels,
during the standards rulemaking for distribution transformers. As set
forth in the Determination notice, the Department can best address
issues as to the technological feasibility, economic justification and
potential energy savings of energy conservation standards in the
standards rulemaking, particularly during evaluation of proposed
standard levels. 62 FR 54810. For many products, such as the types of
distribution transformers at issue here, the question of whether
standards are warranted cannot adequately be addressed without detailed
information and analysis. Once the Department has decided to propose
additional standard levels for distribution transformers, and has
provided its analysis of the levels it has considered in depth,
stakeholders will have an opportunity to comment. They can provide
factual information and analysis on issues such as whether the proposed
standard levels, or other levels, are warranted for particular classes
of transformers, including the types just discussed. These comments
could also address whether some types of transformers should be
completely or partially excluded from standards, including, for
example, whether a portion of K-factor transformers should be excluded
as advocated by Federal Pacific. To the extent information developed
during the standards rulemaking warrants exclusion of any type of
transformers from coverage of the new standards (and test procedures),
the Department will modify its definition of ``distribution
transformer'' accordingly.
5. Rebuilt or Refurbished Distribution Transformers
The Department did not specifically address in the SNOPR whether
today's test procedure, as well as efficiency standards for
distribution transformers, would apply to rebuilt distribution
transformers (i.e., units on which one or more windings have been
replaced), or to used or repaired distribution transformers. Nor does
EPCA specifically address this question. Several commenters stated that
the requirements should apply to rebuilt transformers, commonly
referred to also as refurbished transformers. EMS and HVOLT stated that
coverage of rebuilt units is necessary to close a potential loophole
(EMS, No. 57 at p. 3; HVOLT, No. 53 at p. 3), and ERMCO stated that
failure to cover rebuilt units might enable end-users to avoid
standards by always rewinding failed units. (ERMCO, No. 49 at p. 2)
Manufacturers appeared to be concerned that the increased cost of new,
standards-compliant transformers would cause some customers to either
purchase rebuilt, instead of new, transformers or rebuild existing
transformers they already own. The Oregon Department of Energy agreed
that rebuilt transformers should be required to meet new standards,
indicating that high-quality rewinding practices can produce products
that would meet standards while poor quality work can seriously degrade
performance. (ODOE, No. 54 at p. 2) Some commenters also advocated
coverage of used and/or repaired distribution transformers. (Howard,
No. 55 at p. 3; EMS, No. 57 at p. 3)
EPCA, in essence, seems to require only new distribution
transformers, that have not been sold to end users, to meet Federal
efficiency requirements. (42 U.S.C. 6302, 6316(a) and 6317(a)(1)) Thus,
DOE probably lacks authority to require that used and repaired
transformers comply with its test procedures and standards. The same
may be true for rebuilt transformers, although for them a genuine issue
does exist as to DOE's authority. Generally, EPCA provides that
products, when ``manufactured,'' are subject to efficiency standards.
(42 U.S.C. 6295(b)-(i) and 6313) It is arguable, but by no means clear,
that rebuilt transformers could be considered to be ``manufactured''
again when they are rebuilt, and therefore be classified as new
distribution transformers subject to DOE test procedures and standards.
If, however, rebuilt products cannot be classified as newly
manufactured, DOE would be subject to the same limitation on its
authority to regulate them as applies to used and repaired products. In
addition, contrary to the suggestion of some commenters that DOE
regulate the efficiency of distribution transformers that their owners
have re-wound, and where the transformer is not re-sold, EPCA provides
authority to regulate only products that are sold, imported or
otherwise placed in commerce. (42 U.S.C. 6291, 6311, and 6317(f)(1))
Throughout the history of its appliance efficiency program, DOE has
not sought to regulate used units that have been re-conditioned or
rebuilt, or have undergone major repairs. Regulating this part of the
market, including the enforcement of efficiency requirements, could be
an exceedingly complex and burdensome task. By and large, the
Department believes EPCA indicates a Congressional intent that DOE
focus on the market for new products, and believes that this is where
the largest energy savings can be achieved. For distribution
transformers in particular, the Department understands that at present
rebuilt transformers are only a small part of the market. Moreover, the
core dimensions of existing units are fixed, whereas for many newly
manufactured transformers the dimensions of existing models could be
enlarged in order to allow their efficiencies to increase. Therefore,
at least initially, any standard for rebuilt transformers would likely
have to be lower than for comparable newly manufactured units, and
given the current size of the refurbished transformer market, it
appears that significant energy savings could not be achieved by
adopting standards for them.
For all of these reasons, the Department does not intend to apply
its standards and test procedures to used, repaired and rebuilt
distribution transformers. Nevertheless, the Department recognizes that
there may be some validity to the concerns raised by commenters about
possible substitution of rebuilt for new transformers. If conditions
change--for example, if rebuilt transformers become a larger segment of
the transformer market--DOE will reconsider its decision not to subject
them to energy conservation requirements.
6. Coverage of Liquid-Filled Transformers
Finally, Howard Industries suggested, with regard to liquid-filled
transformers, that the utility, municipal, and co-op segment of the
market not be subject to mandatory standards, because it already uses
life-cycle cost methods in purchasing products, and that only the
commercial and industrial segment be subject to such standards.
(Howard, No. 55 at p. 4) This is an interesting suggestion, but the
Department believes it is untenable because the distribution
transformers used in these two market segments are not sufficiently
different from one another. If the Department were to adopt efficiency
requirements for transformers currently sold in one sector but not the
other, DOE believes that the transformers it left unregulated would
promptly find their way into the regulated market. The Department is
charged with prescribing test procedures and energy conservation
standards for those distribution transformers for which it determines
standards are technologically feasible
[[Page 24982]]
and economically justified and would result in significant energy
savings. Liquid-immersed distribution transformers sold into the
utility, municipal and co-op segments of the market are ``distribution
transformers'' as defined in section 321(35) of EPCA, and, because they
clearly are designed for general purpose applications, DOE could not
exclude them under paragraph (B)(iii) of that section. (42 U.S.C.
6291(35)) Moreover, in October 1997, the Department made a
determination that energy conservation standards for liquid-immersed
distribution transformers would appear to be technologically feasible
and economically justified, and to result in significant energy
savings. 62 FR 54816. For these reasons, today's definition of
``distribution transformer'' does not exclude liquid-immersed
transformers, nor any subset of these transformers destined for any
particular end-user or market segment.
C. Test Procedure for Distribution Transformers
1. General Discussion
The Department developed the test method in today's final rule
(Appendix A to Subpart K of Part 431) in order to have a single,
primary reference that would clearly set forth all testing requirements
for distribution transformers that may be covered by EPCA energy
conservation standards. Almost in its entirety, the test method closely
follows NEMA TP 2-1998 and the following four widely used IEEE
standards: (1) IEEE C57.12.90-1999, ``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) IEEE C57.12.91-2001, ``IEEE Standard Test Code for
Dry-Type Distribution and Power Transformers,'' (3) IEEE C57.12.00-
2000, ``IEEE Standard General Requirements for Liquid-Immersed
Distribution, Power and Regulating Transformers,'' and (4) IEEE
C57.12.01-1998, ``IEEE Standard General Requirements for Dry-Type
Distribution and Power Transformers Including those with Solid Cast
and/or Resin Encapsulated Windings.''
As discussed in the SNOPR, the DOE did not propose to adopt NEMA TP
2-1998 verbatim as the DOE test method because of concerns about
whether TP 2-1998 was sufficiently clear, detailed and accurate to
serve as the DOE test procedure. 69 FR 45508-09. The Department had
also identified problems with the clarity and level of detail in TP 2-
1998 in the 1998 proposed rule. 63 FR 63362. Nor did the Department
propose to incorporate the four IEEE standards by reference. As stated
in the SNOPR, that would require users to consult several reference
documents in order to construct the test procedure, whereas having a
single reference test procedure would reduce the potential of
misinterpreting testing requirements and would enhance the convenience
to users. In addition the IEEE standards include test methods not only
for distribution transformers, but also for much larger power
transformers that are not covered by the DOE test procedure.
Nevertheless, the Department relied heavily on techniques and methods
from NEMA TP 2-1998 and the four IEEE standards in developing the
proposed test procedure and today's final test procedure.
EPACT 2005, which the President signed into law on August 8, 2005,
amended EPCA in effect to direct the Department to develop a test
procedure for distribution transformers that is ``based on'' NEMA TP 2-
1998. (42 U.S.C. 6293(b)(10)). In the SNOPR, DOE stated that it had
``adapted virtually all of the provisions of the [proposed ] test
procedure from NEMA TP 2[-1998] and the * * * four widely used IEEE
standards'' just cited, and had used NEMA TP 2-1998 to develop the
proposed test procedure. 69 FR 45508. The Department did not receive
any comments from stakeholders indicating that they took issue with
these statements. As stated above, today's testing methods are largely
the same as those proposed in the SNOPR. Thus, as also set forth above,
NEMA TP 2-1998 and the IEEE standards are the bases for these test
methods. Indeed, because NEMA TP 2-1998 is based on the IEEE standards,
and represents an attempt to incorporate them into a single document,
any test method that incorporates the substance of these standards
would conform to TP 2-1998. Furthermore, today's test methods and those
in NEMA TP 2-1998 are entirely consistent with one another. For all of
these reasons, it can be fairly stated that today's test procedure is
``based on'' NEMA TP 2-1998, within the meaning of 42 U.S.C.
6293(b)(10), and satisfies the Congressional intent that the DOE test
procedure reflect the content of TP 2.\6\
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\6\ Although NEMA TP 2-1998 contains a sampling plan for
establishing compliance with prescribed efficiency levels, the
compliance sampling plan in today's rule, which is discussed in
section II-E below, is not based on the plan in TP 2. EPACT 2005
mandates that the Department use 12 industry or voluntary test
procedures, each for a different type of product, as the basis for
DOE test procedures for those products. All contain test methods,
but NEMA TP 2-1998 appears to be the only one that contains a
sampling plan. Moreover, for the reasons explained in the SNOPR,
that sampling plan is inconsistent with the standards and labeling
requirements in EPCA for distribution transformers, and with basic,
long-standing elements of DOE's appliance efficiency program. 69 FR
45514. Congress gave no indication in enacting EPACT 2005 that it
intended its mandate for use of NEMA TP 2-1998 to change EPCA's
standards and labeling requirements, or the structure of DOE's
program, for this product. For these reasons, DOE believes Congress
intended to require that DOE's test methods for distribution
transformers, but not its compliance sampling plan, be based on NEMA
TP 2-1998. Accordingly, the Department construes 42 U.S.C.
6393(b)(10) as not affecting the content of its compliance sampling
plan for distribution transformers.
---------------------------------------------------------------------------
In response to the SNOPR, several commenters requested that DOE
rely on existing testing standards as much as possible, as it does for
other products, instead of adopting a new stand-alone test procedure.
(FPT, No. 44 at p. 7; Public Meeting Transcript, No. 42.11 at pp. 49,
54-55) NEMA expressed concern that the Department's proposal differed
significantly from the existing testing methods (NEMA TP 2-1998 and
IEEE), and asserted that industry engineers would need to become
experts in the new method, and that this could be a difficult, time
consuming process. (Public Meeting Transcript, No. 42.11 at pp. 49-51,
53, 60) The Department recognizes that there will be some burden on
manufacturers resulting from today's stand-alone test procedure. This
burden, however, should be minimal. The test methods in the DOE test
procedure are virtually identical to those in the TP 2-1998 and IEEE
standards, and require the same steps for determining losses and
calculating efficiency. Comments from stakeholders offered no specifics
as to why use of the DOE test procedure would be burdensome for
manufacturers and identified no specific provisions in DOE's proposed
test procedure that deviate from the TP 2-1998 or IEEE standards.
Furthermore, in NEMA's revised TP 2 document, TP 2-2005, the test
method closely parallels the SNOPR rule language. (NEMA, No. 60,
Attachment 1) This indicates that, upon further reflection, NEMA
believes use of DOE's proposed test procedure would not be burdensome
for manufacturers.
Federal Pacific states that manufacturers will still be required to
reference industry standards, in addition to DOE standards. (FPT, No.
44 at p. 6) The Department believes that due to the similarities
between today's test procedure and the TP 2-1998 and IEEE documents, a
manufacturer following the DOE test procedure would also be consistent
with NEMA TP 2-1998 and the IEEE test procedures.
[[Page 24983]]
Therefore, manufacturers would not have to take separate steps to
assure compliance with each test procedure.
Federal Pacific also asserts that a stand-alone DOE test procedure
may become a problem if IEEE, ANSI, or NEMA adopt changes to their
standards because the changes may have to be incorporated into the DOE
test procedure. (FPT, No. 44 at pp. 6-7) This issue is not unique to
transformers, and exists whether DOE has a stand-alone test procedure
or incorporates by reference one or more industry standards, such as
the IEEE test methods for transformers. The Department regulates many
other consumer products and commercial equipment, all of which have
test procedures. Some of these are DOE-developed, stand-alone test
methods, and others incorporate by reference industry standards. Even
in the latter situations, no change to an industry standard becomes
part of the DOE test procedure unless and until the Department adopts
it. In the event of an industry-consensus revision to the test methods
for distribution transformers, the Department would consider all
petitions from manufacturers seeking to incorporate those changes into
today's test procedure.
In sum, the Department continues to believe that having a single,
reference test procedure document would enhance the convenience to
users and reduce the potential for misinterpretation of testing
requirements. Today's final rule adheres to that approach rather than
incorporating provisions from the existing industry test procedures.
Commenters did not disagree with the Department's decision not to
adopt NEMA TP 2-1998, without modification, as the DOE test procedure.
In written comments and during the SNOPR public workshop meeting,
however, NEMA proposed that DOE, NEMA and other stakeholders work
together to reach a consensus on needed revisions of TP 2, so that NEMA
could revise it and DOE could then incorporate it by reference. (NEMA,
No. 39 at p. 1; Public Meeting Transcript, No. 42.11 at pp. 22, 49-51,
53, 56-57) NEMA has now completed its revision of TP 2, informing DOE
that it obtained approval from its membership and adopted TP 2-2005 on
September 19, 2005. (NEMA did not indicate whether other stakeholders
were involved in this process.) NEMA proposes that DOE adopt the TP 2-
2005 document as its test procedure for distribution transformers, and
reference it in the final rule for such test procedures. (NEMA, No. 60
at p.1)
The Department believes that such action would be inappropriate.
The Department recognizes NEMA's efforts to revise TP 2 and appreciates
NEMA's openness, including its submission of a draft TP 2-200X document
in March 2005 (NEMA, No. 59 Attachment 1) and the final TP 2-2005
document in September 2005 (NEMA, No. 60 Attachment 1). These
submissions have made a definite contribution to this proceeding. As
indicated elsewhere in this preamble, these submissions identified
changes that were needed in the proposed rule, and that DOE has adopted
in today's final rule. These changes include modification of the
definition of load loss and several editorial changes. As also
discussed in this preamble, however, stakeholder comments submitted in
response to the SNOPR, as well as DOE's own review, have resulted in
many other changes that clarify and improve the proposed test
procedure. These additional changes include provisions for testing
harmonic transformers, clarification of the language concerning test
set neutrals, and an alternative to the proposed method for providing
short-circuiting conductors. None of the additional changes are
reflected in NEMA's final TP 2-2005 document. Moreover, TP 2-2005
contains a number of changes from the SNOPR that should not be included
in today's final rule, such as the exclusion of mining transformers.
For these reasons, the Department is not incorporating TP 2-2005 as its
test procedure rule for distribution transformers. That said, in the
future, the Department would consider incorporating verbatim the NEMA
test method in TP 2 so long as its substance conforms with the test
method then in effect.
2. Specific Provisions of the Test Procedure
a. Testing Harmonic Transformers
As discussed earlier in this notice, the Department proposed in the
SNOPR to exclude both harmonic tolerating (K-factor) transformers with
a K-factor of K-13 or greater and harmonic mitigating transformers from
the definition of distribution transformer, but today's definition
includes both of these types of transformers. Several stakeholders who
recommended removal of the exemption for these transformers, also
recommended that the test procedure should require testing using a
linear load profile (K=1), namely, using the fundamental-frequency test
current in the measurement of load loss. (NEMA, No. 47 at p. 1; NEMA,
No 51 at p. 1; HVOLT, No. 53 at pp. 2-3; PQI, No. 56 at p. 3) Federal
Pacific stated that absent an industry standard harmonic load profile,
K=1 is the only available method for consistently testing transformers
designed for harmonic currents. (Public Meeting Transcript, No. 42.11
at pp. 33-34) Federal Pacific also commented that it uses K=1 to test
K-factor transformers when a customer specifies a K-factor transformer
but also wants it to meet TP 1 efficiency levels. (FPT, No. 44 at p. 2)
When a harmonic transformer is tested with a linear load, however, its
measured losses are lower than the losses it would experience under
non-linear loads. Therefore, the efficiency rating that results from
testing the transformer with a linear load will be higher than the
actual efficiency of the harmonic transformer during normal operation
(i.e., when the transformer is subject to non-linear loads).
Nevertheless, as one commenter indicated, testing harmonic transformers
at linear loads does offer a straight-forward testing method that
avoids over-complicating the issue. (FPT, No. 44 at p. 3, and No. 52 at
p. 2) The Department believes that if its efficiency standards become
applicable to K-factor and harmonic mitigating transformers, more
efficient harmonic transformers will be manufactured than if the
standard did not apply to them. DOE agrees with the above comments, and
therefore today's final rule, in Section 4.1 of the test procedure,
requires that manufacturers test these transformers using fundamental-
frequency test current (corresponding to a linear (K=1)) load.
b. Determining Winding Temperatures
Today's test procedure expands the options available to
manufacturers for determining the winding temperature of liquid
immersed transformers. IEEE C.57.12.90-1999 provides that the
temperature of windings of a liquid-immersed transformer is assumed to
be the same as the temperature of the liquid in which the windings are
immersed. Adding specificity to this approach, the Department proposed
in the SNOPR that the winding temperature of a liquid-immersed
distribution transformer would be the average of two temperature
sensing devices applied to the outside of the transformer tank, at top
oil level and at the bottom of the tank. Howard Industries questioned
the accuracy of this method for determining winding temperatures, and
recommended instead that DOE require direct (internal) top and bottom
measurement of the liquid temperature to determine winding temperature.
(Howard, No. 45 at p. 1)
[[Page 24984]]
The Department understands that the most common method in the
distribution transformer industry for estimating the temperature of
liquid immersed windings is by using thermocouples attached to the
exterior of the transformer tank, as proposed in the SNOPR.
Furthermore, as also proposed in the SNOPR, today's rule requires that
winding temperature be measured only after certain conditions have
stabilized, which provides greater assurance that these external
measurements are a good estimate of the winding temperature. For these
reasons, DOE believes Howard's recommendation that DOE require direct
top and bottom measurement of the liquid could impose significant and
unnecessary burdens on manufacturers. Nevertheless, the Department
recognizes that such direct measurements would be at least as accurate
as external measurements, and that testers who prefer to make direct
measurements should be allowed to do so. Therefore, today's final rule
allows manufacturers to determine the winding temperature using either
exterior tank measurements or direct liquid measurements.
The Department understands that testers normally make external tank
temperature measurements using thermocouples that are designed to be
thermally insulated from the surrounding environment. The use of
insulated thermocouples reduces error in the temperature measurement,
and offers greater accuracy in determining the winding temperatures.
Therefore, the Department has modified the language in proposed section
3.2.1 to clarify that these external temperature measurements must
involve the use of insulated thermocouples.
In addition, proposed section 3.2.1 would give manufacturers the
choice of waiting to measure winding temperature until either (a) the
windings have been under insulating liquid with no excitation and no
current in the windings for four hours before the direct current (dc)
resistance is measured; or (b) the temperature of the insulating liquid
has stabilized, and the difference between the top and bottom
temperature does not exceed 5 [deg]C. These conditions each provide
assurance that the temperature of the windings has stabilized when
manufacturers measure it. The Department took these two conditions from
IEEE C57.12.90-1999, which requires that both be met when the tester
measures the winding temperature. Howard Industries commented that the
DOE test procedure should also require that both be met, to be
consistent with the IEEE standard. (Howard, No. 45 at p. 2) The
Department recognizes the value of being consistent with IEEE. However,
the Department does not believe that for distribution transformers,
meeting both conditions is necessary. The IEEE standard encompasses kVA
ratings of transformers that are much larger (up to 500,000 kVA and
larger) than those covered by today's final rule (no larger than 2,500
kVA). The Department believes that for distribution transformers, which
are relatively small compared to many of the kVA ratings addressed by
IEEE, manufacturers can achieve accurate winding temperature readings
if one of these two conditions is met. Therefore, the language in
today's final rule does not require that both conditions be met.
The Department has also made some clarifying and editorial changes
to the language of section 3.2.2 in today's rule, which concerns
determination of the winding temperature of dry-type transformers.
Section 5.2 of IEEE C57.12.91-2001 allows for the determination of such
winding temperatures, for both ventilated and sealed units, through
either direct measurement or use of the ambient temperature of the test
area. The IEEE standard permits the latter, however, only under certain
conditions. The Department intended to incorporate the IEEE approach in
section 3.2.2 of the test procedure in the SNOPR, but that language
appeared instead to permit use of the ambient temperature only in
determining the winding temperatures of sealed units, and to apply the
conditions for use of ambient temperature also to use of direct
measurement. Section 3.2.2 of today's final rule contains revised
language that clearly incorporates the IEEE approach.
c. Test Set Neutrals
Part 4.0 of the proposed test procedure set forth provisions for
determining transformer losses, including requirements for the test
circuits and test sets used during testing. Section 4.3.3 of the SNOPR
required use of a ``four-wire, three-wattmeter test circuit,'' and, for
delta-wound transformers, use of ``a neutral deriving transformer * * *
to obtain neutral and ground.'' Commenting on this section, Howard
Industries stated that ``[t]here are options for the design of the
power source used to test distribution transformers,'' and recommended
adding to this section the phrase ``unless the source is WYE
connected.'' (Howard, No. 45 at p. 2) Although the Department does not
agree with the change Howard recommended, this comment indicates a need
to clarify section 4.4.3. A wye-connected power source can be used to
test either a wye-or delta-wound transformer, and a neutral deriving
transformer is not needed, and rarely if ever used, to obtain a neutral
and ground. The Department has added language to today's final rule to
make clear that the test procedure allows the use of wye- and delta-
wound power source transformers for testing, and only requires use of a
neutral deriving transformer in conjunction with a delta-wound
transformer.
Today's final rule also contains a few editorial changes with
respect to section 4.3.3 of the SNOPR test procedure. First, because
the first sentence of that section, as proposed, concerned three-phase
distribution transformers generally and not merely test set neutrals,
DOE has now moved the language to section 4.3.2. Second, the remaining
language of section 4.4.3 in the SNOPR related only to testing of
three-phase transformers, and therefore it has been renumbered in
today's final rule as section 4.3.2.3 (part of Three-Phase Test Sets).
Third, to improve clarity, the term ``grounding transformer'' has
replaced the term ``neutral deriving transformer'' throughout the test
procedure. This is because ``grounding transformer'' is more widely
understood in the distribution transformer community as referring to
the type of transformer used to create a grounded neutral for a delta-
wound transformer.
d. Losses From Auxiliary Devices
Sections 4.4.3.1 and 4.5.3.1 of the SNOPR test procedure required
losses attributable to test instrumentation to be deducted from
measured no-load and load losses, respectively, in determining the
total losses of a transformer. Commenters suggested that the final rule
also require manufacturers, in determining load losses, to exclude
those losses attributable to auxiliary devices installed on a
distribution transformer but which are separate from the transformer,
such as circuit breakers, fuses, and switches, because such losses are
not related to losses from the transformer's windings. (Howard, No. 45
at p. 1, and No. 55 at p. 3; ERMCO, No. 49 at pp. 1-2) These commenters
raise a valid concern, although today's final rule permits, but does
not require, the deduction or exclusion of auxiliary device losses from
the measured load losses.
When a distribution transformer is equipped with auxiliary devices
(generally specified by the customer), these devices produce some
energy losses, albeit relatively small in comparison to the unit's
total losses.
[[Page 24985]]
DOE anticipates that its efficiency standards would apply to
distribution transformers without regard to whether auxiliary devices
are installed. The standards therefore would not govern the efficiency
of auxiliary devices, but instead would apply to the performance of the
basic transformer (the equipment to which the auxiliary devices are
added). Because the Department is concerned that some manufacturers may
find it burdensome or problematic to exclude all or part of the losses
attributable to auxiliary devices, each manufacturer will have the
discretion to include or exclude some or all of the auxiliary-device
losses in the determination of load losses. Although exclusion of all
such losses would result in a more accurate efficiency rating for the
transformer being tested, inclusion of such losses would understate the
efficiency rating of the transformer, and not circumvent any applicable
standard. The purchaser would be receiving a slightly more efficient
piece of equipment than indicated by the rating. This approach is
consistent with the Department's regulations in other portions of its
appliance standards program, which generally allow manufacturers the
discretion to rate their products at efficiencies lower than could be
justified by test results. e.g., 10 CFR section 430.24. It is also
consistent with the IEEE standards, which set forth test methods for
distribution transformers but do not require exclusion of losses from
accessories in measuring transformer losses.
Today's final rule also takes this same approach for
instrumentation losses. For the reasons just stated, the Department
believes DOE's test procedure should permit, but not require, (as
proposed in the SNOPR) that manufacturers deduct instrumentation losses
from total losses in determining transformer efficiencies. This will
allow manufacturers greater flexibility than was provided by the SNOPR
proposal, with no detriment to the public or circumvention of any
applicable standard.
Therefore, section 4.5.3.1 of today's test procedure allows
manufacturers to exclude from measured load losses those losses
attributable to auxiliary devices, and sections 4.4.3.1 and 4.5.3.1
allow exclusion of losses attributable to testing instruments from both
no-load and load losses. The Department has, however, slightly modified
the SNOPR language in proposed sections 4.4.3.1 and 4.5.3.1 that
identified the sources of instrumentation losses. The final rule omits
the reference to ``ammeter'' because, upon further consideration, DOE
now realizes that no measured transformer losses are attributable to
this instrument. The Department has also made two other similar
modifications. The term ``wattmeter'' is replaced by ``wattmeter
voltage circuit'' because a wattmeter experiences losses through both
its current and voltage circuits, but only losses from the voltage
circuit are part of measured transformer losses. The term ``instrument
transformer'' is changed to ``voltage transformer'' because
``instrument transformer'' refers to both current and voltage
transformers, both of which experience losses, and it is only losses of
the voltage transformer that are part of measured transformer losses
and should be deducted from the total measured losses. None of these
revisions is a departure from the substance of the SNOPR. Rather they
improve the precision of the final rule and reduce the risk of
misinterpretation or misapplication of the test procedure.
With respect to how to deduct the losses from auxiliary devices
from the measured load losses, one commenter suggested exclusion of the
losses from auxiliary devices by removing the devices (Howard, No. 45
at p. 1), and another suggested excluding the losses by deducting them
from measured losses. (ERMCO, No. 49 at p. 2) Because the Department
believes both approaches are sound, and would produce the same results,
today's final rule allows manufacturers the flexibility of using either
one.
e. Testing of Multiple Voltage Transformers
Today's final rule also clarifies treatment of dual-or multiple-
voltage transformers under the Department's test procedure.
Distribution transformers can be designed with multiple voltage ratings
on the primary and/or secondary windings. Efficiency testing for these
units can be problematic because, for a given transformer and kVA
rating, DOE understands that each transformer will have two or more
different efficiencies, i.e., one efficiency for each of its winding
configurations. In other words, each multiple voltage transformer
experiences different losses (and therefore different efficiencies)
when operated at different voltages. This difference in losses is due
to differences in current associated with the voltage configuration
selected, and generally, the lower voltage ratings will have the higher
losses and therefore lower efficiency ratings. The Department intends,
however, to have just one standard level that would apply to all
transformers in a given class, regardless of the voltage or voltages at
which each transformer in that class is designed to operate.
Howard Industries commented that the efficiency measurement on
series or multiple voltage transformers should always be based on the
highest voltage configuration. (Howard, No. 45 at p. 2; Howard, No. 55
at p. 3) The Department is unable to accept this recommendation,
because a transformer designed to operate at more than one nominal
voltage would have to comply with the standard at all voltage ratings.
Because the lowest voltage ratings would generally have the lowest
efficiency ratings, to ensure that each multiple voltage transformer
complies with the applicable standard at each voltage at which it
operates, the manufacturer would have to determine the transformer's
efficiency by testing it (or by calculating its efficiency using an
AEDM), either at the voltage rating at which the highest losses occur--
generally the lowest voltage--or at each voltage at which the
transformer operates. Therefore, today's final rule requires the
manufacturer to determine the basic model's efficiency either at the
voltage at which the highest losses occur or at each voltage at which
the transformer is rated to operate.
f. Short-Circuiting Conductor Strap
Section 4.5.2 of the SNOPR stated that in the test for measuring
load losses, ``[t]he conductors used to short-circuit the windings must
have a cross-sectional area equal to, or greater than, the
corresponding transformer leads.'' 69 FR 45530. Howard Industries
asserted that other methods exist for providing short-circuiting
conductors or their equivalent, and that the test procedure should also
permit manufacturers to use any short circuiting conductor that is ``of
sufficient size to limit the tare watts to less than 10 percent of the
transformer load losses.'' (Howard, No. 45 at p. 2) In industry
parlance, ``tare watts'' are losses associated with the test set-up,
and in this instance refer to losses in the short-circuiting conductor.
The short-circuiting conductor losses incurred during testing are
included in the measured load losses for the transformer being tested,
but, as discussed above, may be deducted from the measured load losses.
The Department's proposed requirement of a cross sectional area equal
to, or greater than, the corresponding transformer leads is based on
use of a simple, routine method for short-circuiting the windings by
means of the shortest practical conductor between the terminals of the
transformer. The Department believes this proposed
[[Page 24986]]
requirement would limit the short-circuiting conductor losses to
approximately one to three percent of the transformer's measured load
losses. Howard's recommended revision contemplates allowing a less
conventional approach, and would allow losses in the short-circuiting
strap to be as much as ten percent of the load losses.
The Department's proposal generally follows the approach taken in
the relevant IEEE standards. The IEEE standards are voluntary, however,
and do not preclude manufacturers from using new, improved methods that
do not strictly adhere to those standards. But incorporating the
standards into DOE's test procedure would make them mandatory and limit
manufacturer flexibility to use such new methods.
The determination of losses in the short-circuiting strap is
subject to errors, which will contribute to the overall error in the
determination of transformer losses because manufacturers can deduct
the short-circuiting losses from the measured load losses in making
their determination of total losses. DOE is concerned that increasing
the permissible losses, as proposed by Howard, might also increase the
overall error--perhaps beyond acceptable limits--unless appropriate
care is exercised to determine the higher losses of the short-
circuiting conductor. Today's rule, however, does not permit automatic
deduction of 10 percent or any other fixed percent of losses
denominated as occurring in the short-circuiting conductor or any other
instrument or device. Instead, the rule provides that, in determining
measured load losses, manufacturers may deduct only the losses
``attributable'' to the short-circuiting conductor (as well as certain
other instruments and devices). Thus, the rule allows deduction only of
actual losses, i.e., losses determined with a reasonable degree of
accuracy. Moreover, notwithstanding any increase in the amount of error
that would be introduced by adoption of Howard's proposal in today's
rule, the overall limit on the range of error for measurement of power
losses remains at 3 percent, as proposed in the SNOPR.
Thus, adoption of the proposal would not have a significant effect on
overall results determined under the test procedure.
For these reasons, today's rule allows manufacturers to use
alternatives to the method specified in proposed section 4.5.2(b) for
providing short-circuiting conductors, so long as such alternatives do
not result in losses that are 10 percent or more of the total load
losses. The language to implement this approach, however, varies
slightly from the language proposed by Howard Industries. Howard's
proposed language could be construed as permitting losses as great as
10 percent, even if a manufacturer uses the method prescribed in the
SNOPR. The Department sees no reason to allow that, and believes losses
of that magnitude should be permitted only if a manufacturer uses
alternative methods.
g. Revisions Suggested by NEMA in TP 2-2005
As stated above, NEMA prepared a revised version of NEMA TP 2-1998
and submitted it to the Department for review. (NEMA, No. 60 at p. 1)
The Department compared this document, designated by NEMA as TP 2-2005
(NEMA, No. 60 Attachment 1), with the rule language proposed in the
SNOPR to identify all changes to the SNOPR's methods, procedures and
language. For the purposes of this final rule, DOE is treating the
differences that it identified as written comments submitted by NEMA on
the SNOPR. The following discussion examines the significant
differences that DOE has not addressed elsewhere in this notice.
NEMA's TP 2-2005 contains a definition for ``tolerances on measured
losses'' which was not provided in the SNOPR and which reads:
``Measured values of electrical power, voltages, currents, resistances,
and temperature are used in the calculations of reported data. To
ensure sufficient accuracy in the measured and calculated data, the
test system accuracy for each measurement shall fall within the limits
specified in Table 4.'' (NEMA, No. 60 Attachment 1, p. 8) The
Department has not added this definition to the list of terms it is
defining in the final rule because it believes such a definition would
not further clarify or add substance to the rule. Except for its range
for frequency measurement accuracy, Table 2-1 \7\ of TP 2-2005 sets
forth the same accuracy ranges as are contained in Table 2.1 in the
SNOPR. Moreover, section 2.0 of DOE's test procedure states that
``measurement error will be limited to the values shown in Table 2.1.''
69 FR 45524. The Department believes these accuracy requirements for
the measurement of losses are sufficient and clear, and a definition of
``tolerances on measured losses'' is therefore unnecessary.
---------------------------------------------------------------------------
\7\ In the March 2005 draft of NEMA TP 2-200X, Table 4,
Measurement Accuracy Requirements, was the correct citation. In
preparing the final draft, Table 4 was re-labeled as Table 2-1, and
all the values remained the same. The language on page 8 of TP 2-
2005 makes references to Table 4; however, this appears to be a
typographical error as there is no Table 4 in TP 2-2005.
---------------------------------------------------------------------------
As just indicated, Table 2-1 of NEMA TP 2-2005 contains an accuracy
range for frequency measurement of 0.5 percent. (NEMA, No.
60 Attachment 1, p. 9) The Department has decided not to add such a
provision to Table 2.1 of today's final rule, however, for the
following reasons. First, neither TP 2-1998 nor the widely-used IEEE
test methods, which DOE used to develop today's test procedure, contain
an accuracy range for frequency measurement. Secondly, except in
unusual cases, it is not needed. When power is supplied from the
utility grid, frequency is very accurate and there is no need to
prescribe a frequency accuracy or require manufacturers to take steps
to assure accuracy. The Department would only require manufacturers to
assure accuracy when the power supply is not synchronized with an
electric utility grid, and this is addressed in sections 4.4.2 and
4.5.2 of the SNOPR. Thus, the Department has not added a frequency
accuracy range to Table 2.1.
Compared to the SNOPR, NEMA's TP 2-2005 contains slightly different
and longer definitions of ``load'' and ``no-load'' loss. The SNOPR
reads that ``[l]oad loss means, for a distribution transformer, those
losses incident to a specified load carried by the transformer,
including losses in the windings as well as stray losses in the
conducting parts of the transformer. It does not include no-load
losses.'' NEMA's revised TP 2-2005 reads ``load loss: The load losses
of a transformer are those losses incident to the carrying of a
specified load by the transformer. Load losses include I\2\R loss in
the windings due to load and eddy currents; stray losses due to leakage
fluxes in the windings, core clamps, and other parts, and the loss due
to circulating currents (if any) in parallel windings, or in parallel
winding strands.'' (NEMA, No. 60 Attachment 1, p. 4) The Department has
not modified its proposed definition of ``load loss,'' except by
deleting the last sentence as NEMA did in TP 2-2005. The Department
recognizes that inclusion of this last sentence would make the
definition inaccurate, because an insignificant amount of no-load loss
is included in the measurement of load loss. Also, retention of this
sentence might incorrectly imply that manufacturers should subtract
this extremely small amount of no-load loss from load-loss
measurements, to determine load loss.
However, DOE believes that the remainder of its proposed definition
of ``load loss'' is clear and not susceptible
[[Page 24987]]
of misunderstanding, and its brevity is preferable to the approach in
TP 2-2005. The description of the various components of ``load loss''
in the NEMA definition helps explain the causes of load loss, but
neither alters nor clarifies the definition or the requirements that
the definition delineates. Such explanation generally is not included
in rule language.
Concerning the definition of ``no-load loss,'' the Department's
SNOPR reads: ``[n]o-load loss means those losses that are incident to
the excitation of the transformer.'' NEMA's revised TP 2 definition
reads: ``no-load (excitation) loss: No-load (excitation) losses are
those losses that are incident to the excitation of the transformer.
No-load (excitation) losses include core loss, dielectric loss,
conductor loss in the winding due to excitation current, and conductor
loss due to circulating current in parallel windings. These losses
change with the excitation voltage.'' Again, the Department considers
the SNOPR definition to be clear and complete for the purposes of this
test procedure. As with its suggested definition of ``load loss,''
NEMA's definition of ``no-load loss'' adds information, but its list of
components is explanatory rather than substantive, and DOE has concerns
similar to those discussed for the ``load loss'' definition. For these
reasons, the Department is not modifying, except as indicated, either
the ``no-load loss'' or the ``load loss'' definitions.
NEMA TP 2-2005 introduces a definition of ambient temperature.
(NEMA, No. 60 Attachment 1, p. 3) This definition appears to be derived
from the American Society of Heating, Refrigerating and Air-
Conditioning Engineers (ASHRAE) Terminology of Heating, Ventilation,
Air Conditioning, & Refrigeration (Second Edition) and has several
elements that apply to types of transformers that are not distribution
transformers. Therefore, it is not applicable to the Department's test
procedure. Moreover, DOE believes that, in the context of today's final
rule, ambient temperature clearly refers to the room temperature in the
location where the measurements are being taken, as DOE intends. For
these reasons, the Department believes a definition of ambient
temperature is unnecessary in today's rule.
Finally, NEMA TP 2-2005 contains a number of editorial changes to
the language in the SNOPR's test methods. The Department has
incorporated several of these, such as edits in the first paragraph of
proposed section 6.1, in today's final rule.
h. Language Corrections as to Conversion of the Resistance Measurement
to the Reference Temperature and Conducting the No-Load Loss Test
Section 3.5 of DOE's proposed test procedure provided an equation
for correcting measured resistance to the resistance at the reference
temperature. 69 FR 45527. One of the terms of this equation,
Tk, consists of a temperature level for copper windings,
another for aluminum windings, and a third level ``[w]here copper and
aluminum windings are employed in the same transformer.'' However, a
separate resistance measurement is performed for each winding of a
distribution transformer. Section 3.5 provides for adjustment of each
such measurement, and each winding will be either copper or aluminum,
but not both. Therefore, the equation for adjusting the measured
resistance need not, and should not, include a temperature level that
contemplates the use of the two metals together, and in today's final
rule, the Department has deleted from section 3.5 the language that
includes such a temperature level.
Section 4.4.2 of the proposed test procedure concerns testing for
no-load losses. Proposed paragraph (b) of that section directed the
tester to ``[e]nergize not less than 25 percent'' of either the high
voltage or low voltage winding. 69 FR45530. The Department drew the 25
percent figure from section 8.2.3 of IEEE C57.12.90-2001 and C57.12.91-
2001, which recommend energizing 100 percent of the winding in
conducting this test, but allow as low as 25 percent. The IEEE
standards allow the 25 percent because they apply not only to
distribution transformers but also to power transformers. Power
transformers may require much higher voltages than are available in the
power sources used in performing the no-load test. Distribution
transformers, however, require much lower voltages, which can be
accommodated by the available power sources. Moreover, distribution
transformers rarely have a 25-percent voltage tap that would permit
energizing a winding at 25 percent of its rated voltage, and DOE
understands that instead, in testing distribution transformers for no-
load losses, windings are energized to 100 percent of rated voltage.
Hence, DOE has deleted from today's final rule the provision allowing
testers to energize 25 percent or more of a winding.
Proposed paragraph (c) of section 4.4.2 required certain conditions
with respect to voltage during the no-load loss test, ``unless
otherwise specified.'' 69 FR 45530. Once again, DOE drew the quoted
language from IEEE standards, where it is included to accommodate
testing as to characteristics other than efficiency, in situations
where a transformer includes special features requested by a customer.
Because this language has no application to efficiency testing, and
such testing must always be conducted under the conditions specified in
proposed paragraph (b), section 4.4.2(c) of today's final rule does not
include this language.
D. Basic Model
1. General Discussion
Under the Department's energy conservation program, DOE has applied
the ``basic model'' concept to alleviate burden on manufacturers, by
reducing the amount of testing they must do to rate the efficiencies of
their products. DOE's intent is that a manufacturer would treat each
group of its models that have essentially identical energy consumption
characteristics as a ``basic model,'' such that the manufacturer would
derive the efficiency rating for all models in the group from testing
sample units of these models. All of the models in the group would
comprise the ``basic model,'' and they would all have the same
efficiency rating. The proposed definition of basic model for
distribution transformers implements this approach by permitting
manufacturers to aggregate models that have the same energy consumption
characteristics, but not models with different characteristics.
Components of similar design can be substituted in a basic model
without requiring additional testing if the represented measures of
energy consumption continue to satisfy applicable provisions for
sampling and testing.
2. Definition of a Basic Model
In the SNOPR, the Department proposed a definition of ``basic
model'' for distribution transformers that included essentially the
same criteria as those contained in the definition proposed in the 1998
proposed rule, plus a requirement that the transformers included in the
basic model ``not have any differentiating electrical, physical or
functional features that affect energy consumption.'' DOE made several
other modifications to the definition, and described these changes in
the SNOPR. 69 FR 45512-13.
NEMA commented that the SNOPR definition of ``basic model'' was too
vague and needed clarification. (Public Meeting Transcript, No. 42.11
at pp. 22-23) Specifically NEMA was concerned
[[Page 24988]]
that the phrase added to the end of the basic model definition ``and do
not have any differentiating electrical, physical, or functional
features that affect energy consumption'' is unclear. (NEMA, No. 39 at
p. 2) DOE believes that these general criteria for the creation of
basic models are needed to allow manufacturers the flexibility to
create basic model groupings that reflect product features that affect
energy consumption. To address NEMA's concern, DOE is modifying the
definition slightly to provide that voltage and basic impulse
insulation level (BIL) rating are both examples of differentiating
electrical features that would cause transformer models to be different
basic models. DOE stated in the preamble of the SNOPR that each of
these features would be a differentiating electrical characteristic,
but the proposed definition itself did not include these examples.
Additionally, NEMA noted it would prefer that the rule contain a
table of basic models (NEMA, No. 39 at p. 2) or a tighter definition.
(Public Meeting Transcript, No. 42.11 at p. 37) DOE believes that
creation of a table of basic models would be impractical for several
reasons. First, there are literally thousands of possible designs for
any one kVA rating and combination of core steel and winding materials.
Second, for DOE to attempt to identify both the energy consumption
profile of each such combination of transformer features, as well as
the combinations that have common profiles, would be an enormous
undertaking. Third, to the extent that any significant number of these
possible transformer variations is not produced, either now or in the
future, effort may be wasted. And fourth, DOE believes that neither it
nor industry can accurately anticipate all future design variations of
distribution transformers. A table or other rigid definition,
therefore, would (1) fail to provide for future designs, and/or (2)
conflict with the rationale for using the ``basic model'' construct,
and (3) force future designs to be grouped with models that do not
share their energy consumption characteristics. As this last point
indicates, NEMA's concern that the part of the definition quoted above
could allow additional basic models at a later date is misplaced. To
the extent that the definition would allow creation of additional basic
models that subsume models with new energy consumption characteristics,
this indicates the definition is sound rather than in need of
alteration.
DOE recognizes that, given the large number of variations in
distribution transformer design, many manufacturers produce numerous
basic models. The Department is aware, however, of no reasonable way to
aggregate models with different energy consumption characteristics, for
purposes of testing, that would produce an accurate efficiency rating
for each model included in the grouping. Today's final rule, however,
will allow manufacturers to rate the efficiency of many of their
transformers based on calculations instead of testing, by using
alternative efficiency determination methods. This should substantially
alleviate any potential testing burden created by a manufacturer's
producing large numbers of basic models.
In summary, DOE will slightly modify the proposed definition of
``basic model'' to explicitly provide that (1) voltage and BIL ratings
are examples of differentiating electrical features that would cause
transformer models to be different basic models, and (2) each basic
model would comprise a group of models of distribution transformers.
Otherwise, the proposed definition is sound because its specific
elements and general criteria combine to allow the grouping of models
with similar energy consumption characteristics without allowing models
with different characteristics to be included in the same group.
E. Manufacturer's Determination of Efficiency
1. General Discussion
During this rulemaking, NEMA advocated DOE adoption of the sampling
plan for compliance testing in NEMA TP 2-1998, which would allow
manufacturers to demonstrate the compliance of aggregations of basic
models, and the Department presented and solicited comment on several
alternative approaches for demonstrating such aggregate compliance. For
the reasons discussed in the SNOPR, the Department chose not to propose
adoption of either the NEMA TP 2-1998 sampling plan or an alternative
approach allowing aggregation. 69 FR 45513-15.
Instead, the Department has adopted both a sampling plan for
compliance testing, and provisions allowing use of alternative methods
(other than actual testing), for manufacturers to use to determine the
efficiency of individual basic models of distribution transformers. As
proposed in the SNOPR, today's rule requires each manufacturer to
determine the efficiency of each of its basic models on a one-time
basis by testing, at least five with compliance testing, and by rating
each of the remaining basic models either by testing it, or, under the
conditions set forth in the rule, by calculating the basic model's
efficiency using an alternative efficiency determination method (AEDM).
Where the manufacturer uses an AEDM for a basic model, it would not
test units of the basic model to determine its efficiency for purposes
of establishing compliance with DOE requirements.
2. Sampling Plan
The Department designed the sampling plan in today's final rule to
provide a high probability that manufacturers would find each basic
model to be in compliance with the efficiency level at which it is
manufactured, but without creating a significant probability that
models would be found to meet levels higher than those at which they
are manufactured. The latter--``false positives''--would in effect
create a regulatory loophole, by allowing transformer models
manufactured at efficiency levels below applicable standards to be
rated as compliant with those standards. The Department's goal for
distribution transformers is to have about a 97.5 percent probability
that tests on sample units of a basic model would verify or support an
efficiency rating for the model that is equal to or less than the
average efficiency of all units of that model manufactured. Stated
alternatively, a basic model that is manufactured at or above its rated
efficiency would have a probability of not less than 97.5 percent of
passing the compliance demonstration test--i.e., being found in
compliance with its rated value--based on test results using any sample
size.
To accomplish this goal, DOE incorporated into its proposed
sampling plan a one-sided statistical z-test, with a 97.5 percent
confidence limit for average efficiency or power loss, which
manufacturers would apply to the test results derived from testing
sample units of a basic model. The 97.5 percent confidence limit in the
one-sided z-test corresponds to 2[sigma]/[radic]n, where [sigma]
represents the standard deviation of units of distribution
transformers, and n is the number of units, including one, in the
sample. Thus, for example, if a manufacturer tested a sample of only
one unit of a basic model, and its measured power loss did not exceed
the rated power loss of the basic model by more than the amount
representing two standard deviations, the test would confirm the
validity of the rated efficiency. By way of further example, if the
manufacturer tested a sample of more than one unit, the numerical value
for losses corresponding to the 97.5
[[Page 24989]]
percent confidence limit would decrease, and the precision of the
determination of the average losses for the basic model would increase.
In developing the SNOPR, DOE had information both to support a
standard deviation (SD) for distribution transformers of 2.7 percent
and to support one of 4 percent. Since the information in support of
the 2.7 percent level was slightly stronger, DOE based the confidence
limit (or ``tolerance'') \8\ in the SNOPR sampling plan on the SD of
2.7 percent. 69 FR 45515. Two SDs of 2.7 percent correspond to a
tolerance for the average efficiency of the sample of units tested of
5/[radic]n percent. (Most commenters who commented on the sampling plan
tolerance level addressed it as a straight numerical amount, although
in actuality the proposed tolerance is a tolerance that depends on the
size of the sample of units tested, and is 5/[radic]n percent. The
commenters may have used straight numerical amounts because application
of the expression 5/[radic]n percent to a sample size of one would
always result in a flat five-percent tolerance.)
---------------------------------------------------------------------------
\8\ The precise statistics term ``confidence limit'' is
frequently replaced in engineering applications by a more general
term ``tolerance.'' In the preceding discussion, DOE used the
precise term to explain the basis of the tolerance in the SNOPR's
proposed sampling plan for compliance testing. The Department will
use the term ``tolerance'' in the discussion that follows,
particularly because all of those who commented on this issue used
this term.
---------------------------------------------------------------------------
The Department received several comments stating that its proposed
tolerance was too stringent, and should be relaxed. NEMA notes that the
Department's equation relating the average efficiency of the sample and
the represented efficiency assumes a tighter performance probability
distribution function than is achievable in practice, particularly for
small manufacturers. (NEMA, No. 47 at p. 3; NEMA, No. 51 at p. 3)
Four commenters requested that the tolerance for individual units
be relaxed from the SNOPR proposal of five percent to eight percent.
(ERMCO, No. 43 at p. 2; FPT, No. 44 at p. 6; Howard, No. 45 at p. 2;
EMS, No. 57 at p. 3) Federal Pacific commented that use of a five-
percent tolerance is too stringent given the variability of transformer
losses, particularly the variability of no-load losses. (FPT, No. 44 at
p. 6) EMS and ERMCO recommend that the tolerance should be eight
percent to be consistent with IEEE/ANSI C57.12.00 and NEMA TP 2. (EMS,
No. 57 at p. 3; ERMCO, No. 43 at p. 2) Howard Industries also
recommended that the minimum acceptable efficiency level calculation be
based on an eight-percent tolerance on total loss. (Howard, No. 45 at
p. 2)
Four commenters advocated a 12-percent tolerance, which would
equate to three SDs of 4 percent. (Cooper, No. 46 at pp. 1-2; HVOLT,
No. 53 at pp. 1-2; PQI, No. 56 at pp. 1-2; NEMA, No. 59 at p. 1, NEMA,
No. 60, Attachment 1 at p. 34) This tolerance level would increase the
compliance demonstration probability to 99.9 percent, but would also
allow for a significant probability of false positives. For example, a
basic model designed with losses 2 percent above its rated value would
have a 99.4-percent probability of being found to have an efficiency at
or above its rated level if the sample size is one, and would have a
97-percent probability of being found to have such an efficiency if the
sample size is five. In addition, a 12-percent tolerance would be
inconsistent with the much smaller tolerance, for rejection of single
units, in existing IEEE standards. For these reasons, the Department is
not incorporating the 12-percent tolerance level into its sampling
plan.
Three of the commenters advocating the 12-percent tolerance for
compliance testing based their position in part on the assertion that
DOE's rule for electric motors allows a 20-percent ``test tolerance
band.'' (Cooper, No. 46 at p. 2; HVOLT, No. 53 at p. 2; PQI, No. 56 at
p. 2) The tolerance to which they refer in the electric motors rule is
not applicable to distribution transformers for two reasons. First, the
20-percent tolerance in the motors rule applies during testing that
occurs in enforcement proceedings. The rule uses this tolerance to
determine the adequacy of the size of the test sample used in the
proceeding, following testing of the initial sample, and determination
of the sample's mean, standard deviation, and standard error. This 20-
percent tolerance has no relevance to compliance testing. Second,
application of a particular tolerance with respect to efficiency and
losses for electric motors does not indicate the appropriate tolerance
for distribution transformers. Induction motors have a similarity to
transformers in that their stator and rotor windings are akin somewhat
to the primary and secondary windings of a transformer. However, at
that point the similarity ends. A transformer has no moving parts in
normal operation whereas a motor's main feature is the spinning of the
rotor, a mechanical process which in itself absorbs considerable
energy. Thus, motors, in addition to having electrical power losses,
also have mechanical losses. Consequently the comparison of motors and
transformers when discussing tolerances used in determining efficiency
is inappropriate.
Based on the information provided in comments, DOE now believes
that 4 percent is the better SD to use, and that the available
information supporting the 4 percent figure outweighs that supporting
the 2.7-percent SD. Two SDs at 4 percent equates to an eight-percent
single unit tolerance, and results in a tolerance for the average
efficiency of the sample of units tested of 8/[radic]n percent.
Increasing the tolerance from 5/[radic]n percent to 8/[radic]n percent
increases the probability of demonstrating compliance of a product
manufactured at the applicable standard level from about 89 percent to
about 98 percent, without introducing a significant probability that a
product manufactured below the standard level would be found in
compliance. This assumes that the variability of units of the basic
model being tested have a standard deviation of 4 percent. The
probability of a significant false positive--finding a model in
compliance with its rated efficiency where on average the units of that
model as manufactured actually experience a power loss 2-percent larger
than the rated loss--is approximately 93 percent for a sample of one
unit and 81 percent for a sample of five units. Both probabilities,
especially the second one, are sufficiently low that a manufacturer
would not risk producing a product with power losses 2 percent or more
above the losses at which it seeks to rate the product. Thus, today's
final rule increases the tolerance from 5/[radic]n percent to 8/
[radic]n percent.
Several manufacturers submitted comments asking that DOE confirm
that they have the option of testing all transformers of a basic model
or some basic models. (Public Meeting Transcript, No. 42.11 at p. 22;
NEMA, No. 39 at p. 2) One stakeholder requested clarification that if
it chooses to test 100 percent of its production, it would not have to
use the sampling plan or an AEDM (alternative efficiency determination
method). (Public Meeting Transcript, No. 42.11 at p. 65) NEMA also
requested clarification on the number of samples that would have to be
tested if the sample size is small. (Public Meeting Transcript, No.
42.11 at p. 67)
As indicated above, once efficiency standards for distribution
transformers have gone into effect, today's rule will require each
manufacturer to rate the efficiency of each of its basic models on a
one-time basis. The rating would enable the manufacturer to establish
that the basic model complies with the applicable standard, and provide
the basis for any energy representations
[[Page 24990]]
(e.g., labeling and certification) required by DOE. 69 FR 45514. The
Department intended in its SNOPR proposal, and wishes to confirm with
respect to today's rule, that where a manufacturer arrives at this
rating through testing, rather than use of an AEDM, the sampling plan
would permit the manufacturer to test 100 percent of the units
available for testing. The language of section 431.194(b)(2) of the
final rule has been modified to make this clear. Thus, where
manufacturers have on hand more than five units of a basic model at the
time they do compliance testing to rate the basic model, or produce
more than five over a six-month period, they would have the discretion
to rate the basic model based on testing either all of the units or a
sample of at least five units. In addition, the final rule clearly
requires compliance testing of 100 percent of the units for basic
models for which a manufacturer produces five or fewer units during a
six-month period.
None of the provisions in today's rule would prevent a manufacturer
from doing continuous testing of 100 percent of the units it produces
in order to meet contractual obligations to report to its customers the
losses, efficiency or other energy consumption characteristics of each
individual unit it sells to them. Nor does the Department anticipate
that provisions it may adopt, for assuring compliance with energy
conservation standards and for manufacturer representations (e.g.,
labeling) as to efficiency, would prevent manufacturers from testing
all of their units in order to meet such obligations.
3. Alternative Efficiency Determination Method (AEDM)
Under the proposed rule, a manufacturer would have to validate each
AEDM it uses based on test data for at least five basic models, derived
by testing at least five units of each of these basic models. 69 FR
45522. Taken together, these provisions would require testing of at
least 25 units to validate an AEDM. Howard Industries commented that
five basic models is too small a sample to adequately represent all the
different kVA/voltages/BIL requirements when validating an AEDM and
recommended that DOE require 75 models to be tested to validate an
AEDM. (Howard, No. 45 at p. 3, and No. 55 at p. 3) Howard also asserted
that five basic models was too low a number to verify that the AEDM
would accurately predict the efficiency of all liquid-immersed
transformers. It stated that transformers vary considerably, with a
large number of design options. (Howard, No. 58 at p. 1) In addition to
containing the validation requirement, however, the final rule (in
section 431.197(a)(2)(i)) also precludes a manufacturer from applying
an AEDM to a basic model unless ``the AEDM has been derived from a
mathematical model that represents the electrical characteristics of
that basic model.'' Thus, apart from any testing to validate the
accuracy of an AEDM, this language will require each AEDM to represent
any unique or custom-designed electrical characteristics of any basic
model to which it applies. DOE believes that this provision
satisfactorily addresses Howard's concern that DOE require AEDMs to
reflect the particular characteristics of the transformers to which
they apply.
The Department believes that to require each AEDM to be validated
based on testing of 75 basic models, or some other number larger than
five, would create undue burden. The foregoing is particularly true
because DOE understands that manufacturers use design models and
software to design their distribution transformers, and DOE believes
that most AEDMs would be derived from, or consist of, such models and
software. Since these design tools would have validity independent of
the AEDM substantiation required by DOE regulations, extensive testing
to substantiate the validity of AEDMs appears to be unnecessary.
Section 432.12(a)(2)(iii) of the proposed rule restricted the use
of each AEDM to one of the following groups of distribution
transformers: low-voltage dry-type transformers, medium-voltage dry-
type transformers, and liquid-immersed transformers. 69 FR 45522. Upon
further review, the Department believes that this provision is too
restrictive, and that manufacturers should be permitted to use a single
AEDM for distribution transformers in two or all three of these groups,
so long as the manufacturer validates the AEDM separately for each
group. The Department is aware of no reason why it should limit use of
each AEDM to transformers in one of these groups, if the AEDM can
validly predict the efficiency for transformers in more than one group.
Accordingly, today's final rule allows a single AEDM to apply to two or
all three of these groupings. See 10 CFR section 431.197(a)(2) of the
rule. The rule also requires that the manufacturer validate each AEDM
separately for each group--i.e., low-voltage dry-type, medium-voltage
dry-type, and liquid-immersed--for which it uses the AEDM, based on
test data for five basic models from such group. 10 CFR section
431.197(a)(2)(iii) of the rule. Thus to substantiate a single global
AEDM that would apply to the entire range of distribution transformers
(all three groups), a manufacturer would have to test not fewer than 15
basic models (a total of at least 75 units), and it would have to test
at least 10 basic models (a total of at least 50 units) to substantiate
an AEDM that would apply to two groups. DOE believes this amount of
testing to validate the AEDM is sufficient.
The SNOPR also included a requirement that manufacturers
``periodically'' verify each AEDM that they use. 69 FR 45523. Howard
Industries recommended that the Department change ``periodically'' to
``annually.'' (Howard, No. 45 at p. 3, and No. 55 at p. 3) The
Department considered this proposal, but decided that annual
verification of an AEDM, which could include testing, could be unduly
burdensome on manufacturers. The Department has also decided, however,
largely because of the particular circumstances of the distribution
transformer industry, to eliminate the periodic verification
requirement from today's final rule. Many distribution transformer
manufacturers already engage in continuous testing--sometimes by
testing 100 percent of their units--to assure that the actual
performance, including efficiency, of their products conforms to the
manufacturer's design software and representations to customers. In
addition, other provisions of today's final rule authorize DOE to
obtain information from manufacturers concerning their use of AEDMs,
and to require a manufacturer to do sample testing or take other steps.
Thus, DOE now believes that mandatory, periodic, subsequent
verification of AEDMs for distribution transformers is unwarranted.
F. Enforcement Procedures
The SNOPR included proposed enforcement procedures, including a
sampling plan and other provisions for enforcement testing. 69 FR
45415-17, 45523-23, 45533-34. The Department based the proposed
procedures on enforcement provisions in 10 CFR Part 430, which apply
when DOE examines whether a basic model of a covered product complies
with efficiency requirements set forth in those parts. The SNOPR's
enforcement sampling plan was based on the plan in Part 430, but was
developed specifically for distribution transformers. It allows testing
of small sample sizes and applies only to energy efficiency testing,
whereas the Part 430 plan contemplates
[[Page 24991]]
larger sample sizes and covers energy use testing.
NEMA requested clarification on when the process of enforcement
commences. (Public Meeting Transcript, No. 42.11 at p. 73) The
Department initiates the enforcement process when it receives
information, either from a third party or other source, indicating that
a manufacturer's units may not be in compliance with the national
standard. Initially, DOE seeks to meet with the manufacturer and review
its underlying test data as to the models in question. DOE would
commence enforcement testing procedures if these steps do not resolve
identified compliance issues.
The Department also received comments relating to enforcement as to
stock units and imported units. Cooper sought clarification on
application of efficiency standards to units in stock when standards
take effect, and to foreign manufacturers. (Cooper, No. 46 at p. 2)
Traditionally, new DOE standards for a product have applied to units
manufactured after a certain date, or, in the case of foreign-
manufactured units, imported after that date. See, e.g., 42 U.S.C.
6291, 6295, 6311 and 6313. The Department anticipates that this will
also be the case for distribution transformers. Therefore, the
efficiency levels would not apply to units in a domestic manufacturer's
stock prior to the date standards become applicable, or to units
imported prior to that date. In all other respects, DOE anticipates
that the same requirements and enforcement provisions that apply to
domestic units will also apply to imported units. In addition, however,
imported units are subject to the provisions of 42 U.S.C. 6301 of EPCA,
concerning importation of products subject to EPCA requirements.
HVOLT commented that the Department should require that the
efficiency of any foreign-built transformer be verified by a third
party before it can be sold in the U.S. (HVOLT, No. 53 at p. 3) The
Department believes that this issue is outside the scope of this
rulemaking. Today's final rule does not address the DOE administrative
framework for manufacturers to follow to demonstrate compliance with
distribution transformer energy conservation standards. The Department
will likely address such requirements in conjunction with the standards
rulemaking.
The SNOPR enforcement sampling plan contained several calculation
equations. 69 FR 45533. Federal Pacific requested further explanation
and examples of the enforcement calculations. (FPT, No. 44 at p. 6) As
explained in the SNOPR, the statistical methods used in those
calculations were based on well-established statistical methods for
obtaining a confidence interval on a mean. 69 FR 45516. Hence, the
Department believes these calculations can be understood by any
statistician. In addition, a complete explanation is set forth in NIST
Technical Note 1456, Operating Characteristics of the Proposed Sampling
Plans for Testing Distribution Transformers, May 2004, which has been
placed in the docket for this rulemaking and is publicly available at
http://www.eere.energy.gov/buildings/appliance_standards/commercial/dist_transformers.html. On the other hand, it would be very burdensome
for DOE to develop and include in this notice a detailed explanation,
in layman's terms, of the statistics and operation of these equations.
Furthermore, these equations will be used by DOE, and would not be
applied by manufacturers. For these reasons, the Department has
concluded that the type of explanation Federal Pacific requests is
unwarranted, and would add little useful information to the record of
this rulemaking.
III. Procedural Requirements
A. Review Under Executive Order 12866
The Office of Information and Regulatory Affairs of the Office of
Management and Budget (OMB) has determined that today's regulatory
action is not a ``significant regulatory action'' under Executive Order
12866, ``Regulatory Planning and Review,'' 58 FR 51735 (October 4,
1993). Accordingly, this action was not subject to review under the
Executive Order.
B. Review Under the Regulatory Flexibility Act of 1980
The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires
preparation of an initial regulatory flexibility analysis for any rule
that by law must be proposed for public comment, unless the agency
certifies that the rule, if promulgated, will not have a significant
economic impact on a substantial number of small entities. As required
by Executive Order 13272, Proper Consideration of Small Entities in
Agency Rulemaking, 67 FR 53461 (August 16, 2002), DOE published
procedures and policies on February 19, 2003, to ensure that the
potential impacts of its rules on small entities are properly
considered during the rulemaking process. 68 FR 7990. The Department
has made its procedures and policies available on the Office of General
Counsel's Web site: http://www.gc.doe.gov.
The Department reviewed today's final rule under the provisions of
the Regulatory Flexibility Act and the procedures and policies
published on February 19, 2003, and certified in the SNOPR that the
proposed rule would not impose a significant economic impact on a
substantial number of small entities. 69 FR 45517. As indicated in
section I-A above, when it issued the SNOPR DOE was concurrently
pursuing a rulemaking to develop energy conservation standards for low-
voltage dry type, medium-voltage dry type and liquid immersed
distribution transformers. The Department explained in the SNOPR that,
unless and until DOE adoption of such standards, no entities, small or
large, would be required to comply with today's final rule. 69 FR
45517. Once the Department adopted standards, however, the rule would
become binding on, and could have an economic impact on, small entities
which manufacture the distribution transformers subject to the
standards. But the nature and extent of such impact, if any, could not
be assessed until the Department has promulgated the standards. The
Department stated in the SNOPR that, in light of these circumstances,
at an appropriate point in conjunction with the standards rulemaking,
it will conduct further review under the Regulatory Flexibility Act.
The Department received no comments on this issue in response to the
SNOPR.
For medium-voltage dry-type and liquid immersed distribution
transformers, DOE is continuing to pursue its standards-development
rulemaking and the circumstances described in the SNOPR still exist.
Therefore, after considering the potential impact of this final rule on
small entities that manufacture these transformers, DOE affirms the
certification that this rule will not have a significant economic
impact on a substantial number of these small entities.
Low-voltage dry-type distribution transformers, however, are no
longer included in DOE's rulemaking on energy conservation standards
for distribution transformers. Instead, EPCA, as amended in EPACT
20005, now specifies minimum standards for all such transformers
manufactured after January 1, 2007, 42 U.S.C. 6295(y), and the
Department has incorporated those standards into its regulations. 10
CFR section 431.196. Because today's rule will apply to all
distribution transformers that become subject to standards, as of
January 1, 2007, the rule
[[Page 24992]]
would become binding on all manufacturers, small and large, of low-
voltage dry-type distribution transformers. Consequently, under the
Regulatory Flexibility Act, the Department must assess the economic
impact of this rule on small manufacturers of these transformers.
Small businesses, as defined by the Small Business Administration
(SBA) for the distribution transformer manufacturing industry, are
manufacturing enterprises with 750 employees or fewer. The Department
estimates that, of a total of approximately 55 manufacturers of low-
voltage dry-type distribution transformers, about 45 are small
businesses under the SBA definition. In today's rule, the enforcement
provisions and the methods manufacturers must use to rate its products
could potentially impose burdens on these small manufacturers. But DOE
has examined these aspects of the rule and determined that they will
not have a significant economic impact on a substantial number of small
manufacturers of low-voltage dry-type distribution transformers.
As to the enforcement provisions, they require DOE to first attempt
to resolve a transformer's possible non-compliance with EPCA
requirements by reviewing available information and meeting with the
manufacturer. Then, if necessary, DOE must test sample units of the
allegedly non-complying basic model(s) to determine whether they
comply. See Section 431.198 of the attached rule. Only provisions that
come into play once DOE invokes testing--specifically, manufacturers
must provide and ship sample units to DOE and must retain all units in
the batch sample until a final determination of compliance or non-
compliance, and manufacturers may conduct additional testing at their
own expense if the DOE testing indicates non-compliance--could impose a
significant burden on manufacturers.
None of the enforcement provisions imposes on-going duties on
manufacturers. They apply only when an issue of compliance is raised,
which at this point is speculative. Indeed, even when they are invoked
as to a particular manufacturer, they will only apply to the specific
basic model(s) at issue. Moreover, these types of enforcement
provisions have been in place for DOE's program for appliance energy
conservation standards for more than 15 years, and the Department has
commenced the process at most two or three times a year. In every
instance it has resolved the matter without proceeding to enforcement
testing, the only part of the process that could impose a significant
burden on manufacturers. For all of these reasons the Department
concludes that the enforcement provisions in today's rule will not have
a significant impact on a substantial number of entities, whether small
or large.
As to the methods for manufacturers to rate the efficiencies of
low-voltage dry-type distribution transformers, DOE notes initially
that requirements for testing and rating these transformers are already
implicit in EPCA. Specifically, to comply with EPCA's efficiency
standards for low-voltage dry-type distribution transformers, 42 U.S.C.
6295(y), manufacturers will have to determine the efficiencies of any
such transformers they produce. This necessarily entails the use of
testing and rating methods, and if DOE does not prescribe such methods,
manufacturers would still be subject to the burden of using such tools.
In addition, as noted above, EPCA requires DOE to prescribe testing
requirements for any transformers subject to standards, and states that
these requirements ``shall be based on'' NEMA TP 2-1998. 42 U.S.C.
6293(b)(10) and 6317(a). Although these provisions allow the Department
substantial discretion in prescribing a test method for distribution
transformers, they indicate that EPCA contemplates that the DOE method
likely would impose burdens equivalent or similar to those imposed by
NEMA TP 2-1998. Thus, today's rule itself has an impact on small
manufacturers only to the extent it imposes an incremental burden
beyond what they would be required to do to comply with EPCA's
standards or NEMA TP 2-1998.
This is significant under the Regulatory Flexibility Act because
the Act applies only where the agency's rule has a significant impact
on small entities. It does not apply to a rule if the agency certifies
that ``the rule will not * * * have a significant impact on a
substantial number of small entities.'' 5 U.S.C. 605(a) (Emphasis
added). Thus, the Act does not apply, for example, where the agency
merely incorporates statutory requirements into its rules, or adopts
the equivalent of statutory requirements without adding any significant
impact on small entities. In such instances, it is the statutory
requirements, and not the agency's rule, that could have an impact on
small entities. The Department therefore examines in the following
paragraphs whether today's rule imposes any burdens on small entities
beyond those imposed by EPCA.
In prescribing efficiency rating methods, today's rule (1)
addresses the number of its basic models a manufacturer must rate
through actual testing and how may units of each it must test, (2)
prescribes a detailed method for testing each unit, and (3) provides
for use of alternative efficiency determination methods for
transformers that manufacturers do not rate through testing. See
Section 431.193 and 431.197 of the attached rule. As to whether today's
method for testing each unit is more burdensome than NEMA TP 2-1998,
the two are nearly identical except that the Department's method adds
technical detail, clarifying language, and editorial improvements.
Thus, the DOE method is no more burdensome, and may alleviate burden
because it reduces the need for manufacturers to do background work to
provide missing details and clarify ambiguous provisions.
Nor does today's test method impose significantly, if any, more
burden than other methods a small manufacturer might reasonably use to
comply with the EPACT standards for low-voltage dry-type transformers.
A manufacturer might choose to use NEMA TP 2-1998, which as just
indicated is no more burdensome than today's method, or NEMA TP 2-2005,
which is almost word-for-word the same as the SNOPR's test method and
which varies little from today's rule. A manufacturer might also craft
a test method from the standards of accepted engineering practice as
set forth in IEEE standards. On the one hand, except for the
requirements as to equipment calibration in today's rule, the test
method in the rule is the equivalent to the method in the four relevant
IEEE standards. On the other hand, DOE believes it is possible that
small manufacturers might each be able to modify the details of the
IEEE test method so as to best fit its products. As a result its costs
of testing needed to comply with the EPACT efficiency standards, i.e.,
implicit in the EPACT requirements, could be lower than the cost of
testing under the test method in today's rule. The Department believes
that such savings would not be significant, and to some extent would be
offset by the resources a small manufacturer would have to expend to
research and develop such a customized test method. Today's method does
include requirements to calibrate equipment and maintain records of
such calibrations, which are not explicitly included in the IEEE
standards. But to achieve the accuracy levels required under these
standards, a manufacturer would have to engage in some calibration
effort. In any event, DOE estimates that today's rule would
[[Page 24993]]
require only about one week of staff time to satisfy the calibration
requirements in the first year the rule is operative, and about two
days a year thereafter. For the foregoing reasons, the Department
concludes that, although today's test method might impose modest
burdens on small manufacturers of low-voltage dry-type distribution
transformers, these burdens are not significant.
However, the final rule's provisions as to the amount of testing
required to rate distribution transformer efficiencies are clearly far
less burdensome to small manufacturers than methodologies currently in
use. The rule requires each manufacturer to test at least five basic
models. For each such model, the manufacturer must test the lesser of
all units manufactured over a 180 day period or five units, and must
rate the basic model's efficiency by applying a formula to the test
results. The rule also allows use of AEDMs to rate the remaining basic
models. The IEEE standards contain no provision for sampling, or for
use of AEDMs, in rating the efficiency of distribution transformers.
Moreover, DOE understands that, under current practice, where a
manufacturer must rate a low-voltage dry-type transformer's losses--the
equivalent of efficiency determination--typically it will test all
units and rate them based on their average efficiency. Although, as
explained below in footnote 6, EPCA does not direct DOE to use the
sampling regimen in NEMA TP 2-1998, that is a methodology a
manufacturer might use to determine whether its low-voltage dry-type
transformers comply with EPCA's standards. NEMA TP 2-1998's sampling
plan provides that, over a 180-day period, either all units
manufactured be tested, or that five or more units per month be tested,
thus requiring approximately six times as much testing as today's rule.
It also contains no provision for rating transformer efficiencies
through use of AEDMs. As explained in the SNOPR, 69 FR 45514-15, NEMA
TP 2-1998 clearly requires considerably more testing that today's final
rule (which requires the same amount of testing as DOE's proposal in
the SNOPR).
Insofar as the final rule's reduction in testing burden results
from the use of AEDMs, however, this benefit is not without cost. The
Department estimates that a manufacturer would have to incur
approximately three to six weeks of engineering staff time to develop a
valid AEDM, and approximately two weeks of staff time to administer and
maintain the AEDM(s) thereafter. The Department estimates, however,
that use of AEDMs would allow a manufacturer to do less than 20 percent
of the testing that would otherwise be required.
For all of these reasons, the Department certifies that today's
final rule would not have a significant economic impact on a
substantial number of small entities. Accordingly, DOE has not prepared
a regulatory flexibility analysis for this rulemaking. DOE has
transmitted the certification and supporting statement of factual basis
to the Chief Counsel for Advocacy of the Small Business Administration
for review pursuant to 5 U.S.C. 605(b).
C. Review Under the Paperwork Reduction Act
As indicated in the SNOPR, today's final rule contains certain
record-keeping requirements. 69 FR 45517. The situation with respect to
the Paperwork Reduction Act (44 U.S.C. 3501 et seq.) is similar to that
described in Section III.B. with respect to the Regulatory Flexibility
Act. For the reasons stated there, unless and until the Department
requires manufacturers to comply with energy conservation standards for
medium-voltage and liquid immersed distribution transformers, no
manufacturer of those products would be required to comply with these
record-keeping provisions. Therefore, today's rule would not impose on
those manufacturers any new reporting requirements requiring clearance
by OMB under the Paperwork Reduction Act. The Department recognizes,
however, as also set forth in the SNOPR, that if it adopts standards
for those distribution transformers, once the standards become
operative manufacturers will become subject to the record-keeping
requirements in today's rule, and possibly additional reporting and/or
record-keeping requirements. 69 FR 45517.
We received no comments on this issue. For medium-voltage and
liquid immersed distribution transformers, the Department intends, as
stated in the SNOPR, to comply with the Paperwork Reduction Act with
respect to the record-keeping requirements in today's rule at the
appropriate point in conjunction with the standards development
rulemaking.
Since the publication of the SNOPR, however, the Department has
adopted standards prescribed by EPCA for low-voltage dry-type
distribution transformers. When these standards become operative on
January 1, 2007, manufacturers of those products will be required to
comply with the record-keeping provisions in today's rule. Therefore,
as to these manufacturers today's final rule contains certain record-
keeping requirements that must be approved by the OMB pursuant to the
Paperwork Reduction Act before the manufacturers may be required to
comply with them. Section 431.197(a)(4)(i) would require manufacturers
of distribution transformers to have records as to alternative
efficiency determination methods available for DOE inspection; section
6.2 of Appendix A would require maintenance of calibration records. As
a result, concurrent with or shortly after publication of today's rule,
the Department will issue a notice seeking public comment under the
Paperwork Reduction Act, with respect to these manufacturers, on the
record-keeping requirements in today's rule. After considering any
public comments received in response to that notice, DOE will submit
the proposed collection of information to OMB for approval pursuant to
44 U.S.C. 3507.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. As stated in the ``EFFECTIVE DATE''
line of this notice of final rulemaking, the information collection
requirements in Sec. 431.197(a)(4)(i) and section 6.2(b) and (c) of
Appendix A will not become effective until OMB approves them. The
Department will publish a document in the Federal Register advising
low-voltage dry-type manufacturers of their effective date. That
document also will display the OMB control number.
D. Review Under the National Environmental Policy Act of 1969
DOE has determined that this rule falls into a class of actions
that are categorically excluded from review under the National
Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and the
Department's implementing regulations at 10 CFR part 1021.
Specifically, this rule establishing test procedures will not affect
the quality or distribution of energy and, will not result in any
environmental impacts, and, therefore, is covered by the Categorical
Exclusion in paragraph A6 to subpart D, 10 CFR part 1021. Accordingly,
neither an environmental assessment nor an environmental impact
statement is required.
E. Review Under Executive Order 13132
Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 4,
1999), imposes certain requirements on agencies formulating and
implementing policies or regulations that preempt State law or that
have federalism implications. The Executive Order requires agencies to
[[Page 24994]]
examine the constitutional and statutory authority supporting any
action that would limit the policymaking discretion of the States and
carefully assess the necessity for such actions. The Executive Order
also requires agencies to have an accountable process to ensure
meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.
On March 14, 2000, DOE published a statement of policy describing the
intergovernmental consultation process it will follow in the
development of such regulations 65 FR 13735. DOE has examined today's
final rule and has determined that it does not preempt State law and
does not have a substantial direct effect on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government. No further action is required by Executive Order 13132.
F. Review Under Executive Order 12988
With respect to the review of existing regulations and the
promulgation of new regulations, section 3(a) of Executive Order 12988,
``Civil Justice Reform'' (61 FR 4729, February 7, 1996), imposes on
Federal agencies the general duty to adhere to the following
requirements: (1) Eliminate drafting errors and ambiguity; (2) write
regulations to minimize litigation; and (3) provide a clear legal
standard for affected conduct rather than a general standard and
promote simplification and burden reduction. Section 3(b) of Executive
Order 12988 specifically requires that Executive agencies make every
reasonable effort to ensure that the regulation: (1) Clearly specifies
the preemptive effect, if any; (2) clearly specifies any effect on
existing Federal law or regulation; (3) provides a clear legal standard
for affected conduct while promoting simplification and burden
reduction; (4) specifies the retroactive effect, if any; (5) adequately
defines key terms; and (6) addresses other important issues affecting
clarity and general draftsmanship under any guidelines issued by the
Attorney General. Section 3(c) of Executive Order 12988 requires
Executive agencies to review regulations in light of applicable
standards in section 3(a) and section 3(b) to determine whether they
are met or it is unreasonable to meet one or more of them. DOE has
completed the required review and determined that, to the extent
permitted by law, this rule meets the relevant standards of Executive
Order 12988.
G. Review Under the Unfunded Mandates Reform Act of 1995
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) (Pub.
L. 104-4) requires each Federal agency to assess the effects of Federal
regulatory actions on State, local, and Tribal governments and the
private sector. For a proposed regulatory action likely to result in a
rule that may cause the expenditure by State, local, and Tribal
governments, in the aggregate, or by the private sector of $100 million
or more in any one year (adjusted annually for inflation), section 202
of UMRA requires a Federal agency to publish a written statement that
estimates the resulting costs, benefits, and other effects on the
national economy. (2 U.S.C. 1532(a), (b)) The UMRA also requires a
Federal agency to develop an effective process to permit timely input
by elected officers of State, local, and Tribal governments on a
proposed ``significant intergovernmental mandate,'' and requires an
agency plan for giving notice and opportunity for timely input to
potentially affected small governments before establishing any
requirements that might significantly or uniquely affect small
governments. On March 18, 1997, DOE published a statement of policy on
its process for intergovernmental consultation under UMRA. 62 FR 12820
(also available at http://www.gc.doe.gov). Today's rule does not
contain any Federal mandate likely to result in an aggregate
expenditure of $100 million or more in any year, so these requirements
under the Unfunded Mandates Reform Act do not apply.
H. Review Under the Treasury and General Government Appropriations Act
of 1999
Section 654 of the Treasury and General Government Appropriations
Act, 1999 (Pub. L. 105-277) requires Federal agencies to issue a Family
Policymaking Assessment for any rule that may affect family well-being.
This rule would not have any impact on the autonomy or integrity of the
family as an institution. Accordingly, DOE has concluded that it is not
necessary to prepare a Family Policymaking Assessment.
I. Review Under Executive Order 12630
The Department has determined, under Executive Order 12630,
``Governmental Actions and Interference with Constitutionally Protected
Property Rights,'' 53 FR 8859 (March 18, 1988), that this regulation
would not result in any takings which might require compensation under
the Fifth Amendment to the United States Constitution.
J. Review Under the Treasury and General Government Appropriations Act,
2001
Section 515 of the Treasury and General Government Appropriations
Act, 2001 (44 U.S.C. 3516 note) provides for agencies to review most
disseminations of information to the public under guidelines
established by each agency pursuant to general guidelines issued by
OMB. OMB's guidelines were published at 67 FR 8452 (February 22, 2002),
and DOE's guidelines were published at 67 FR 62446 (October 7, 2002).
The Department has reviewed today's final rule under the OMB and DOE
guidelines and has concluded that it is consistent with applicable
policies in those guidelines.
K. Review Under Executive Order 13211
Executive Order 13211, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355
(May 22, 2001) requires Federal agencies to prepare and submit to the
Office of Information and Regulatory Affairs (OIRA), Office of
Management and Budget, a Statement of Energy Effects for any proposed
significant energy action. A ``significant energy action'' is defined
as any action by an agency that promulgated or is expected to lead to
promulgation of a final rule, and that: (1) Is a significant regulatory
action under Executive Order 12866, or any successor order; and (2) is
likely to have a significant adverse effect on the supply,
distribution, or use of energy, or (3) is designated by the
Administrator of OIRA as a significant energy action. For any proposed
significant energy action, the agency must give a detailed statement of
any adverse effects on energy supply, distribution, or use should the
proposal be implemented, and of reasonable alternatives to the action
and their expected benefits on energy supply, distribution, and use.
This final rule is not a significant regulatory action under
Executive Order 12866 or any successor order. In addition, it is not
likely to have a significant adverse effect on the supply,
distribution, or use of energy, nor has it been designated by the
Administrator of OIRA as a significant energy action. Thus, DOE has not
prepared a Statement of Energy Effects.
[[Page 24995]]
L. Review Under Section 32 of the Federal Energy Administration Act of
1974
Under Section 301 of the Department of Energy Organization Act
(Pub. L. 95-91), the Department must comply with Section 32 of the
Federal Energy Administration Act of 1974 (FEAA), as amended by the
Federal Energy Administration Authorization Act of 1977. (15 U.S.C.
788) The Department indicated in the SNOPR that Section 32 applies to
the portion of today's rule that incorporates testing methods contained
in five commercial standards, requiring consultation with the Attorney
General and the Chairman of the Federal Trade Commission concerning the
impact of these standards on competition. 69 FR 45506, 45519 (July 29,
2004).
Since publication of the SNOPR, DOE has reviewed this requirement
for consultation as it applies to this final rule. While DOE now
believes that such consultation is not necessarily required for this
rule, since DOE stated in the SNOPR that it would submit it for
consultation under Section 32, it has done so. Neither the Attorney
General nor the Chairman of the Federal Trade Commission has
recommended against incorporation of these standards.
M. Congressional Notification
As required by 5 U.S.C. 801, DOE will report to Congress on the
promulgation of this rule prior to its effective date. The report will
state that it has been determined that the rule is not a ``major rule''
as defined by 5 U.S.C. 804(2).
IV. Approval of the Office of the Secretary
The Secretary of Energy has approved publication of this final
rule.
List of Subjects in 10 CFR Part 431
Administrative practice and procedure, Distribution transformers,
Energy conservation.
Issued in Washington, DC, on March 28, 2006.
Douglas L. Faulkner,
Acting Assistant Secretary, Energy Efficiency and Renewable Energy.
0
For the reasons set forth in the preamble, Part 431 of Chapter II of
Title 10, Code of Federal Regulations, is amended as set forth below.
PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND
INDUSTRIAL EQUIPMENT
0
1. The authority citation for Part 431 continues to read as follows:
Authority: 42 U.S.C. 6291-6317.
0
2. Section 431.191 is revised to read as follows:
Sec. 431.191 Purpose and scope.
This subpart contains energy conservation requirements for
distribution transformers, pursuant to Parts B and C of Title III of
the Energy Policy and Conservation Act, as amended, 42 U.S.C. 6291-
6317.
0
3. Section 431.192 is amended by:
0
a. Revising the Section heading.
0
b. Adding introductory language.
0
c. Adding in alphabetical order definitions of ``autotransformer,''
``basic model,'' ``drive (isolation) transformer,'' ``efficiency,''
``excitation current or no-load current,'' ``grounding transformer,''
``liquid-immersed distribution transformer,'' ``load loss,'' ``machine-
tool (control) transformer,'' ``medium-voltage dry-type distribution
transformer,'' ``no-load loss,'' ``nonventilated transformer,'' ``phase
angle,'' ``phase angle correction,'' ``phase angle error,'' ``rectifier
transformer,'' ``reference temperature,'' ``regulating transformer,''
``sealed transformer,'' ``special-impedance transformer,''
``temperature correction,'' ``test current,'' ``test frequency,''
``test voltage,'' ``testing transformer,'' ``total loss,''
``transformer with tap range of 20 percent or more,'' ``uninterruptible
power supply transformer,'' ``waveform correction,'' and ``welding
transformer.''
0
d. Revising the definition of ``distribution transformer.''
The revision and additions read as follows:
Sec. 431.192 Definitions.
The following definitions apply for purposes of this subpart:
Autotransformer means a transformer that:
(1) Has one physical winding that consists of a series winding part
and a common winding part;
(2) Has no isolation between its primary and secondary circuits;
and
(3) During step-down operation, has a primary voltage that is equal
to the total of the series and common winding voltages, and a secondary
voltage that is equal to the common winding voltage.
Basic model means a group of models of distribution transformers
manufactured by a single manufacturer, that have the same insulation
type (i.e., liquid-immersed or dry-type), have the same number of
phases (i.e., single or three), have the same standard kVA rating, and
do not have any differentiating electrical, physical or functional
features that affect energy consumption. Differences in voltage and
differences in basic impulse insulation level (BIL) rating are examples
of differentiating electrical features that affect energy consumption.
Distribution transformer means a transformer that--
(1) Has an input voltage of 34.5 kV or less;
(2) Has an output voltage of 600 V or less;
(3) Is rated for operation at a frequency of 60 Hz; and
(4) Has a capacity of 10 kVA to 2500 kVA for liquid-immersed units
and 15 kVA to 2500 kVA for dry-type units; but
(5) The term ``distribution transformer'' does not include a
transformer that is an--
(i) Autotransformer;
(ii) Drive (isolation) transformer;
(iii) Grounding transformer;
(iv) Machine-tool (control) transformer;
(v) Nonventilated transformer;
(vi) Rectifier transformer;
(vii) Regulating transformer;
(viii) Sealed transformer;
(ix) Special-impedance transformer;
(x) Testing transformer;
(xi) Transformer with tap range of 20 percent or more;
(xii) Uninterruptible power supply transformer; or
(xiii) Welding transformer.
Drive (isolation) transformer means a transformer that:
(1) Isolates an electric motor from the line;
(2) Accommodates the added loads of drive-created harmonics; and
(3) Is designed to withstand the additional mechanical stresses
resulting from an alternating current adjustable frequency motor drive
or a direct current motor drive.
Efficiency means the ratio of the useful power output to the total
power input.
Excitation current or no-load current means the current that flows
in any winding used to excite the transformer when all other windings
are open-circuited.
Grounding transformer means a three-phase transformer intended
primarily to provide a neutral point for system-grounding purposes,
either by means of:
(1) A grounded wye primary winding and a delta secondary winding;
or
(2) A transformer with its primary winding in a zig-zag winding
arrangement, and with no secondary winding.
Liquid-immersed distribution transformer means a distribution
transformer in which the core and coil assembly is immersed in an
insulating liquid.
Load loss means, for a distribution transformer, those losses
incident to a specified load carried by the
[[Page 24996]]
transformer, including losses in the windings as well as stray losses
in the conducting parts of the transformer.
* * * * *
Machine-tool (control) transformer means a transformer that is
equipped with a fuse or other over-current protection device, and is
generally used for the operation of a solenoid, contactor, relay,
portable tool, or localized lighting.
Medium-voltage dry-type distribution transformer means a
distribution transformer in which the core and coil assembly is
immersed in a gaseous or dry-compound insulating medium, and which has
a rated primary voltage between 601 V and 34.5 kV.
No-load loss means those losses that are incident to the excitation
of the transformer.
Nonventilated transformer means a transformer constructed so as to
prevent external air circulation through the coils of the transformer
while operating at zero gauge pressure.
Phase angle means the angle between two phasors, where the two
phasors represent progressions of periodic waves of either:
(1) Two voltages;
(2) Two currents; or
(3) A voltage and a current of an alternating current circuit.
Phase angle correction means the adjustment (correction) of
measurement data to negate the effects of phase angle error.
Phase angle error means incorrect displacement of the phase angle,
introduced by the components of the test equipment.
Rectifier transformer means a transformer that operates at the
fundamental frequency of an alternating-current system and that is
designed to have one or more output windings connected to a rectifier.
Reference temperature means 20 [deg]C for no-load loss, 55 [deg]C
for load loss of liquid-immersed distribution transformers at 50
percent load, and 75 [deg]C for load loss of both low-voltage and
medium-voltage dry-type distribution transformers, at 35 percent load
and 50 percent load, respectively. It is the temperature at which the
transformer losses must be determined, and to which such losses must be
corrected if testing is done at a different point. (These temperatures
are specified in the test method in Appendix A to this part.)
Regulating transformer means a transformer that varies the voltage,
the phase angle, or both voltage and phase angle, of an output circuit
and compensates for fluctuation of load and input voltage, phase angle
or both voltage and phase angle.
Sealed transformer means a transformer designed to remain
hermetically sealed under specified conditions of temperature and
pressure.
Special-impedance transformer means any transformer built to
operate at an impedance outside of the normal impedance range for that
transformer's kVA rating. The normal impedance range for each kVA
rating for liquid-immersed and dry-type transformers is shown in Tables
1 and 2, respectively.
Table 1.--Normal Impedance Ranges for Liquid-Immersed Transformers
----------------------------------------------------------------------------------------------------------------
Single-phase transformers Three-phase transformers
----------------------------------------------------------------------------------------------------------------
kVA Impedance (%) kVA Impedance (%)
----------------------------------------------------------------------------------------------------------------
10.............................................................. 1.0-4.5 15 1.0-4.5
15.............................................................. 1.0-4.5 30 1.0-4.5
25.............................................................. 1.0-4.5 45 1.0-4.5
37.5............................................................ 1.0-4.5 75 1.0-5.0
50.............................................................. 1.5-4.5 112.5 1.2-6.0
75.............................................................. 1.5-4.5 150 1.2-6.0
100............................................................. 1.5-4.5 225 1.2-6.0
167............................................................. 1.5-4.5 300 1.2-6.0
250............................................................. 1.5-6.0 500 1.5-7.0
333............................................................. 1.5-6.0 750 5.0-7.5
500............................................................. 1.5-7.0 1000 5.0-7.5
667............................................................. 5.0-7.5 1500 5.0-7.5
833............................................................. 5.0-7.5 2000 5.0-7.5
2500 5.0-7.5
----------------------------------------------------------------------------------------------------------------
Table 2.--Normal Impedance Ranges for Dry-Type Transformers
----------------------------------------------------------------------------------------------------------------
Single-phase transformers Three-phase transformers
----------------------------------------------------------------------------------------------------------------
kVA Impedance (%) kVA Impedance (%)
----------------------------------------------------------------------------------------------------------------
15.............................................................. 1.5-6.0 15 1.5-6.0
25.............................................................. 1.5-6.0 30 1.5-6.0
37.5............................................................ 1.5-6.0 45 1.5-6.0
50.............................................................. 1.5-6.0 75 1.5-6.0
75.............................................................. 2.0-7.0 112.5 1.5-6.0
100............................................................. 2.0-7.0 150 1.5-6.0
167............................................................. 2.5-8.0 225 3.0-7.0
250............................................................. 3.5-8.0 300 3.0-7.0
333............................................................. 3.5-8.0 500 4.5-8.0
500............................................................. 3.5-8.0 750 5.0-8.0
667............................................................. 5.0-8.0 1000 5.0-8.0
833............................................................. 5.0-8.0 1500 5.0-8.0
2000 5.0-8.0
2500 5.0-8.0
----------------------------------------------------------------------------------------------------------------
[[Page 24997]]
Temperature correction means the mathematical correction(s) of
measurement data, obtained when a transformer is tested at a
temperature that is different from the reference temperature, to the
value(s) that would have been obtained if the transformer had been
tested at the reference temperature.
Test current means the current of the electrical power supplied to
the transformer under test.
Test frequency means the frequency of the electrical power supplied
to the transformer under test.
Test voltage means the voltage of the electrical power supplied to
the transformer under test.
Testing transformer means a transformer used in a circuit to
produce a specific voltage or current for the purpose of testing
electrical equipment.
Total loss means the sum of the no-load loss and the load loss for
a transformer.
* * * * *
Transformer with tap range of 20 percent or more means a
transformer with multiple voltage taps, the highest of which equals at
least 20 percent more than the lowest, computed based on the sum of the
deviations of the voltages of these taps from the transformer's nominal
voltage.
Uninterruptible power supply transformer means a transformer that
supplies power to an uninterruptible power system, which in turn
supplies power to loads that are sensitive to power failure, power
sags, over voltage, switching transients, line noise, and other power
quality factors.
Waveform correction means the adjustment(s) (mathematical
correction(s)) of measurement data obtained with a test voltage that is
non-sinusoidal, to a value(s) that would have been obtained with a
sinusoidal voltage.
Welding transformer means a transformer designed for use in arc
welding equipment or resistance welding equipment.
0
4. Section 431.193 is added to subpart K, under the heading ``Test
Procedures,'' to read as follows:
Test Procedures
Sec. 431.193 Test procedures for measuring energy consumption of
distribution transformers.
The test procedures for measuring the energy efficiency of
distribution transformers for purposes of EPCA are specified in
Appendix A to this subpart.
0
5. Section 431.196 is amended in paragraph (a) by revising the table to
read as follows:
Sec. 431.196 Energy conservation standards and their effective dates.
(a) * * *
----------------------------------------------------------------------------------------------------------------
Single phase Three phase
----------------------------------------------------------------------------------------------------------------
Efficiency (%) Efficiency (%)
kVA \1\ kVA \1\
----------------------------------------------------------------------------------------------------------------
15.............................................................. 97.7 15 97.0
25.............................................................. 98.0 30 97.5
37.5............................................................ 98.2 45 97.7
50.............................................................. 98.3 75 98.0
75.............................................................. 98.5 112.5 98.2
100............................................................. 98.6 150 98.3
167............................................................. 98.7 225 98.5
250............................................................. 98.8 300 98.6
333............................................................. 98.9 500 98.7
750 98.8
1000 98.9
----------------------------------------------------------------------------------------------------------------
\1\ Efficiencies are determined at the following reference conditions: (1) for no-load losses, at the
temperature of 20 [deg]C, and (2) for load-losses, at the temperature of 75 [deg]C and 35 percent of nameplate
load.
(Source: Table 4-2 of National Electrical Manufacturers Association (NEMA) Standard TP-1-2002, ``Guide for
Determining Energy Efficiency for Distribution Transformers.'')
* * * * *
0
6. Sections 431.197 through 431.198 are added to subpart K, under the
heading ``Compliance and Enforcement,'' to read as follows:
Compliance and Enforcement
Sec. 431.197 Manufacturer's determination of efficiency for
distribution transformers.
When a manufacturer or other party (both of which this section
refers to as a ``manufacturer'') determines the efficiency of a
distribution transformer in order to comply with an obligation imposed
on it by or pursuant to Part C of Title III of EPCA, 42 U.S.C. 6311-
6317, this section applies. This section does not apply to enforcement
testing conducted pursuant to Sec. 431.198 of this part.
(a) Methods used to determine efficiency--(1) General requirements.
A manufacturer must determine the efficiency of each basic model of
distribution transformer either by testing, in accordance with Sec.
431.193 of this part and paragraphs (b)(2) and (b)(3) of this section,
or by application of an alternative efficiency determination method
(AEDM) that meets the requirements of paragraphs (a)(2) and (a)(3) of
this section; provided, however, that a manufacturer may use an AEDM to
determine the efficiency of one or more of its untested basic models
only if it determines the efficiency of at least five of its other
basic models (selected in accordance with paragraph (b)(1) of this
section) through actual testing. For each basic model of distribution
transformer that has a configuration of windings which allows for more
than one nominal rated voltage, the manufacturer must determine the
basic model's efficiency either at the voltage at which the highest
losses occur or at each voltage at which the transformer is rated to
operate.
(2) Alternative efficiency determination method. A manufacturer may
apply an AEDM to a basic model pursuant to paragraph (a)(1) of this
section only if:
(i) The AEDM has been derived from a mathematical model that
represents the electrical characteristics of that basic model;
(ii) The AEDM is based on engineering and statistical analysis,
computer simulation or modeling, or other analytic evaluation of
performance data; and
(iii) The manufacturer has substantiated the AEDM, in accordance
with paragraph (a)(3) of this section, by applying it to, and testing,
at least five
[[Page 24998]]
other basic models of the same type, i.e., low-voltage dry-type
distribution transformers, medium-voltage dry-type distribution
transformers, or liquid-immersed distribution transformers.
(3) Substantiation of an alternative efficiency determination
method. Before using an AEDM, the manufacturer must substantiate the
AEDM's accuracy and reliability as follows:
(i) Apply the AEDM to at least five of the manufacturer's basic
models that have been selected for testing in accordance with paragraph
(b)(1) of this section, and calculate the power loss for each of these
basic models;
(ii) Test at least five units of each of these basic models in
accordance with the applicable test procedure and paragraph (b)(2) of
this section, and determine the power loss for each of these basic
models;
(iii) The predicted total power loss for each of these basic
models, calculated by applying the AEDM pursuant to paragraph (a)(3)(i)
of this section, must be within plus or minus five percent of the mean
total power loss determined from the testing of that basic model
pursuant to paragraph (a)(3)(ii) of this section; and
(iv) Calculate for each of these basic models the percentage that
its power loss calculated pursuant to paragraph (a)(3)(i) is of its
power loss determined from testing pursuant to paragraph (a)(3)(ii),
compute the average of these percentages, and that calculated average
power loss, expressed as a percentage of the average power loss
determined from testing, must be no less than 97 percent and no greater
than 103 percent.
(4) Subsequent verification of an AEDM. (i) Each manufacturer that
has used an AEDM under this section shall have available for inspection
by the Department of Energy records showing: The method or methods
used; the mathematical model, the engineering or statistical analysis,
computer simulation or modeling, and other analytic evaluation of
performance data on which the AEDM is based; complete test data,
product information, and related information that the manufacturer has
generated or acquired pursuant to paragraph (a)(3) of this section; and
the calculations used to determine the efficiency and total power
losses of each basic model to which the AEDM was applied.
(ii) If requested by the Department, the manufacturer shall conduct
simulations to predict the performance of particular basic models of
distribution transformers specified by the Department, analyses of
previous simulations conducted by the manufacturer, sample testing of
basic models selected by the Department, or a combination of the
foregoing.
(b) Additional testing requirements--(1) Selection of basic models
for testing if an AEDM is to be applied. (i) A manufacturer must select
basic models for testing in accordance with the following criteria:
(A) Two of the basic models must be among the five basic models
with the highest unit volumes of production by the manufacturer in the
prior year, or during the prior 12-calendar-month period beginning in
2003,\1\ whichever is later;
---------------------------------------------------------------------------
\1\ When identifying these five basic models, any basic model
that does not comply with Federal energy conservation standards for
distribution transformers that may be in effect shall be excluded
from consideration.
---------------------------------------------------------------------------
(B) No two basic models should have the same combination of power
and voltage ratings; and
(C) At least one basic model should be single-phase and at least
one should be three-phase.
(ii) In any instance where it is impossible for a manufacturer to
select basic models for testing in accordance with all of these
criteria, the criteria shall be given priority in the order in which
they are listed. Within the limits imposed by the criteria, basic
models shall be selected randomly.
(2) Selection of units for testing within a basic model. For each
basic model a manufacturer selects for testing, it shall select and
test units as follows:
(i) If the manufacturer would produce five or fewer units of a
basic model over a reasonable period of time (approximately 180 days),
then it must test each unit. However, a manufacturer may not use a
basic model with a sample size of fewer than five units to substantiate
an AEDM pursuant to paragraph (a)(3) of this section.
(ii) If the manufacturer produces more than five units over such
period of time, it must either test all such units or select a sample
of at least five units at random and test them. Any such sample shall
be comprised of production units of the basic model, or units that are
representative of such production units.
(3) Applying results of testing. In a test of compliance with a
represented efficiency, the average efficiency of the sample, X, which
is defined by
[GRAPHIC] [TIFF OMITTED] TR27AP06.000
where Xi is the measured efficiency of unit i and n is the
number of units tested, must satisfy the condition:
[GRAPHIC] [TIFF OMITTED] TR27AP06.001
where RE is the represented efficiency.
Sec. 431.198 Enforcement testing for distribution transformers.
(a) Test notice. Upon receiving information in writing, concerning
the energy performance of a particular distribution transformer sold by
a particular manufacturer or private labeler, which indicates that the
transformer may not be in compliance with the applicable energy
efficiency standard, or upon undertaking to ascertain the accuracy of
the efficiency rating on the nameplate or in marketing materials for a
distribution transformer, disclosed pursuant to this part, the
Department may conduct testing of that equipment under this subpart by
means of a test notice addressed to the manufacturer in accordance with
the following requirements:
(1) The test notice procedure will only be followed after the
Department has examined the underlying test data (or, where
appropriate, data as to use of an AEDM) provided by the manufacturer
and after the manufacturer has been offered the opportunity to meet
with the Department to verify, as applicable, compliance with the
applicable efficiency standard, or the accuracy of labeling
information, or both. In addition, where compliance of a basic model
was certified based on an AEDM, the Department shall have the
discretion to pursue the provisions of Sec. 431.197(a)(4)(ii) prior to
invoking the test notice procedure. The Department shall be permitted
to observe any reverification procedures undertaken pursuant to this
subpart, and to inspect the results of such reverification.
(2) The Department will mail or deliver the test notice to the
plant manager or other responsible official, as designated by the
manufacturer.
(3) The test notice will specify the basic model(s) to be selected
for testing, the method of selecting the test sample, the date and time
at which testing shall be initiated, the date by which testing is
scheduled to be completed and the facility at which testing will be
conducted. The test notice may also provide for situations in which a
specified basic model is unavailable for testing, and may include
alternative basic models. The specified basic model may be one either
that the manufacturer has rated by actual testing or that it has rated
by the use of an AEDM.
(4) The Department may require in the test notice that the
manufacturer shall
[[Page 24999]]
ship at its expense a reasonable number of units of each basic model
specified in such test notice to a testing laboratory designated by the
Department. The number of units of each basic model specified in a test
notice shall not exceed twenty (20).
(5) Except as required or provided in paragraphs (a)(6) or (a)(7)
of this section, initially the Department will test five units.
(6) Except as provided in paragraph (a)(7) of this section, if
fewer than five units of a basic model are available for testing when
the manufacturer receives the test notice, then
(i) DOE will test the available unit(s); or
(ii) If one or more other units of the basic model are expected to
become available within six months, DOE may instead, at its discretion,
test either:
(A) The available unit(s) and one or more of the other units that
subsequently become available (up to a maximum of twenty); or
(B) Up to twenty of the other units that subsequently become
available.
(7) Notwithstanding paragraphs (a)(5) and (a)(6) of this section,
if testing of the available or subsequently available units of a basic
model would be impractical, as for example where a basic model is very
large, has unusual testing requirements, or has limited production, the
Department may in its discretion decide to base the determination of
compliance on the testing of fewer than the available number of units,
if the manufacturer so requests and demonstrates that the criteria of
this paragraph are met.
(8) When testing units under paragraphs (a)(5), (a)(6), or (a)(7)
of this section, DOE shall perform the following number of tests:
(i) If DOE tests four or more units, it will test each unit once;
(ii) If DOE tests two or three units, it will test each unit twice;
or
(iii) If DOE tests one unit, it will test that unit four times.
(9) Within five working days of the time the units are selected,
the manufacturer shall ship the specified test units of the basic model
to the testing laboratory.
(b) Testing laboratory. Whenever the Department conducts
enforcement testing at a designated laboratory in accordance with a
test notice under this section, the resulting test data shall
constitute official test data for that basic model. Such test data will
be used by the Department to make a determination of compliance or
noncompliance.
(c) Sampling. The determination that a manufacturer's basic model
complies with its labeled efficiency, or the applicable energy
efficiency standard, shall be based on the testing conducted in
accordance with the statistical sampling procedures set forth in
Appendix B of this subpart and the test procedures specified for
distribution transformers.
(d) Test unit selection. The Department shall select a batch, a
batch sample, and test units from the batch sample in accordance with
the following provisions of this paragraph and the conditions specified
in the test notice.
(1) The batch may be subdivided by the Department utilizing
criteria specified in the test notice.
(2) The Department will then randomly select a batch sample of up
to 20 units from one or more subdivided groups within the batch. The
manufacturer shall keep on hand all units in the batch sample until
such time as the basic model is determined to be in compliance or non-
compliance.
(3) The Department will randomly select individual test units
comprising the test sample from the batch sample.
(4) All random selection shall be achieved by sequentially
numbering all of the units in a batch sample and then using a table of
random numbers to select the units to be tested.
(e) Test unit preparation. (1) Prior to and during the testing, a
test unit selected in accordance with paragraph (d) of this section
shall not be prepared, modified, or adjusted in any manner unless such
preparation, modification, or adjustment is allowed by the applicable
Department of Energy test procedure.
(2) No quality control, testing, or assembly procedures shall be
performed on a test unit, or any parts and sub-assemblies thereof, that
is not performed during the production and assembly of all other units
included in the basic model.
(3) A test unit shall be considered defective if such unit is
inoperative or is found to be in noncompliance due to failure of the
unit to operate according to the manufacturer's design and operating
instructions. Defective units, including those damaged due to shipping
or handling, shall be reported immediately to the Department. The
Department shall authorize testing of an additional unit on a case-by-
case basis.
(f) Testing at manufacturer's option. (1) If a manufacturer's basic
model is determined to be in noncompliance with the applicable energy
performance standard at the conclusion of Department testing in
accordance with the sampling plan specified in Appendix B of this
subpart, the manufacturer may request that the Department conduct
additional testing of the basic model according to procedures set forth
in Appendix B of this subpart and the test procedures specified for
distribution transformers.
(2) All units tested under this paragraph (f) shall be selected and
tested in accordance with the provisions given in paragraphs (a)(9),
(b), (d) and (e) of this section.
(3) The manufacturer shall bear the cost of all testing conducted
under this paragraph (f).
(4) The manufacturer shall cease distribution of the basic model
tested under the provisions of this paragraph from the time the
manufacturer elects to exercise the option provided in this paragraph
until the basic model is determined to be in compliance. The Department
may seek civil penalties for all units distributed during such period.
(5) If the additional testing results in a determination of
compliance, a notice of allowance to resume distribution shall be
issued by the Department.
0
7. Appendices A and B are added to subpart K, to read as follows:
Appendix A to Subpart K of Part 431--Uniform Test Method for Measuring
the Energy Consumption of Distribution Transformers
1.0 Definitions.
The definitions contained in Sec. Sec. 431.2 and 431.192 are
applicable to this Appendix A.
2.0 Accuracy Requirements.
(a) Equipment and methods for loss measurement shall be
sufficiently accurate that measurement error will be limited to the
values shown in Table 2.1.
Table 2.1.--Test System Accuracy Requirements for Each Measured Quantity
------------------------------------------------------------------------
Measured quantity Test system accuracy
------------------------------------------------------------------------
Power Losses.............................. 3.0%
Voltage................................... 0.5%
Current................................... 0.5%
Resistance................................ 0.5%
Temperature............................... 1.0 [deg]C
------------------------------------------------------------------------
(b) Only instrument transformers meeting the 0.3 metering
accuracy class, or better, may be used under this test method.
3.0 Resistance Measurements
3.1 General Considerations
(a) Measure or establish the winding temperature at the time of
the winding resistance measurement.
(b) Measure the direct current resistance (Rdc) of
transformer windings by one of the methods outlined in section 3.3.
The methods of section 3.5 must be used to correct load losses to
the applicable reference temperature from the temperature at which
they are measured. Observe precautions
[[Page 25000]]
while taking measurements, such as those in section 3.4, in order to
maintain measurement uncertainty limits specified in Table 2.1.
3.2 Temperature Determination of Windings and Pre-conditions for
Resistance Measurement.
Make temperature measurements in protected areas where the air
temperature is stable and there are no drafts. Determine the winding
temperature (Tdc) for liquid-immersed and dry-type
distribution transformers by the methods described in sections 3.2.1
and 3.2.2, respectively.
3.2.1 Liquid-Immersed Distribution Transformers.
3.2.1.1 Methods
Record the winding temperature (Tdc) of liquid-
immersed transformers as the average of either of the following:
(a) The measurements from two temperature sensing devices (for
example, thermocouples) applied to the outside of the transformer
tank and thermally insulated from the surrounding environment, with
one located at the level of the oil and the other located near the
tank bottom or at the lower radiator header if applicable; or
(b) The measurements from two temperature sensing devices
immersed in the transformer liquid, with one located directly above
the winding and other located directly below the winding.
3.2.1.2 Conditions
Make this determination under either of the following
conditions:
(a) The windings have been under insulating liquid with no
excitation and no current in the windings for four hours before the
dc resistance is measured; or
(b) The temperature of the insulating liquid has stabilized, and
the difference between the top and bottom temperature does not
exceed 5 [deg]C.
3.2.2 Dry-Type Distribution Transformers.
Record the winding temperature (Tdc) of dry-type
transformers as either of the following:
(a) For ventilated dry-type units, use the average of readings
of four or more thermometers, thermocouples, or other suitable
temperature sensors inserted within the coils. Place the sensing
points of the measuring devices as close as possible to the winding
conductors. For sealed units, such as epoxy-coated or epoxy-
encapsulated units, use the average of four or more temperature
sensors located on the enclosure and/or cover, as close to different
parts of the winding assemblies as possible; or
(b) For both ventilated and sealed units, use the ambient
temperature of the test area, under the following conditions:
(1) All internal temperatures measured by the internal
temperature sensors must not differ from the test area ambient
temperature by more than 2 [deg]C.
(2) Enclosure surface temperatures for sealed units must not
differ from the test area ambient temperature by more than 2 [deg]C.
(3) Test area ambient temperature should not have changed by
more than 3 [deg]C for 3 hours before the test.
(4) Neither voltage nor current has been applied to the unit
under test for 24 hours. In addition, increase this initial 24 hour
period by any added amount of time necessary for the temperature of
the transformer windings to stabilize at the level of the ambient
temperature. However, this additional amount of time need not exceed
24 hours.
3.3 Resistance Measurement Methods.
Make resistance measurements using either the resistance bridge
method, the voltmeter-ammeter method or a resistance meter. In each
instance when this Uniform Test Method is used to test more than one
unit of a basic model to determine the efficiency of that basic
model, the resistance of the units being tested may be determined
from making resistance measurements on only one of the units.
3.3.1 Resistance Bridge Methods.
If the resistance bridge method is selected, use either the
Wheatstone or Kelvin bridge circuit (or the equivalent of either).
3.3.1.1 Wheatstone Bridge
(a) This bridge is best suited for measuring resistances larger
than ten ohms. A schematic diagram of a Wheatstone bridge with a
representative transformer under test is shown in Figure 3.1.
[GRAPHIC] [TIFF OMITTED] TR27AP06.002
Where:
Rdc is the resistance of the transformer winding being
measured,
Rs is a standard resistor having the resistance
Rs,
Ra, Rb are two precision resistors with
resistance values Ra and Rb , respectively; at
least one resistor must have a provision for resistance adjustment,
Rt is a resistor for reducing the time constant of the
circuit,
D is a null detector, which may be either a micro ammeter or
microvoltmeter or equivalent instrument for observing that no signal
is present when the bridge is balanced, and
Vdc is a source of dc voltage for supplying the power to
the Wheatstone Bridge.
(b) In the measurement process, turn on the source
(Vdc), and adjust the resistance ratio (Ra/
Rb) to produce zero signal at the detector (D). Determine
the winding resistance by using equation 3-1 as follows:
[[Page 25001]]
[GRAPHIC] [TIFF OMITTED] TR27AP06.003
3.3.1.2 Kelvin Bridge
(a) This bridge separates the resistance of the connecting
conductors to the transformer winding being measured from the
resistance of the winding, and therefore is best suited for
measuring resistances of ten ohms and smaller. A schematic diagram
of a Kelvin bridge with a representative transformer under test is
shown in Figure 3.2.
[GRAPHIC] [TIFF OMITTED] TR27AP06.004
(b) The Kelvin Bridge has seven of the same type of components
as in the Wheatstone Bridge. It has two more resistors than the
Wheatstone bridge, Ra1 and Rb1. At least one
of these resistors must have adjustable resistance. In the
measurement process, the source is turned on, two resistance ratios
(Ra/Rb) and (Ra1/Rb1)
are adjusted to be equal, and then the two ratios are adjusted
together to balance the bridge producing zero signal at the
detector. Determine the winding resistance by using equation 3-2 as
follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.005
as with the Wheatstone bridge, with an additional condition that:
[GRAPHIC] [TIFF OMITTED] TR27AP06.006
(c) The Kelvin bridge provides two sets of leads, current-
carrying and voltage-sensing, to the transformer terminals and the
standard resistor, thus eliminating voltage drops from the
measurement in the current-carrying leads as represented by
Rd.
3.3.2 Voltmeter-Ammeter Method.
(a) Employ the voltmeter-ammeter method only if the rated
current of the winding is greater than one ampere and the test
current is limited to 15 percent of the winding current. Connect the
transformer winding under test to the circuit shown in Figure 3.3.
[GRAPHIC] [TIFF OMITTED] TR27AP06.007
Where:
A is an ammeter or a voltmeter-shunt combination for measuring the
current (Imdc) in the transformer winding,
V is a voltmeter with sensitivity in the millivolt range for
measuring the voltage
[[Page 25002]]
(Vmdc) applied to the transformer winding,
Rdc is the resistance of the transformer winding being
measured,
Rt is a resistor for reducing the time constant of the
circuit, and
Vdc is a source of dc voltage for supplying power to the
measuring circuit.
(b) To perform the measurement, turn on the source to produce
current no larger than 15 percent of the rated current for the
winding. Wait until the current and voltage readings have stabilized
and then take simultaneous readings of voltage and current.
Determine the winding resistance Rdc by using equation 3-
4 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.008
Where:
Vmdc is the voltage measured by the voltmeter V, and
Imdc is the current measured by the ammeter A.
(c) As shown in Figure 3.3, separate current and voltage leads
must be brought to the transformer terminals. (This eliminates the
errors due to lead and contact resistance.)
3.3.3 Resistance Meters.
Resistance meters may be based on voltmeter-ammeter, or
resistance bridge, or some other operating principle. Any meter used
to measure a transformer's winding resistance must have
specifications for resistance range, current range, and ability to
measure highly inductive resistors that cover the characteristics of
the transformer being tested. Also the meter's specifications for
accuracy must meet the applicable criteria of Table 2.1 in section
2.0.
3.4 Precautions in Measuring Winding Resistance.
3.4.1 Required actions.
The following guidelines must be observed when making resistance
measurements:
(a) Use separate current and voltage leads when measuring small
(< 10 ohms) resistance.
(b) Use null detectors in bridge circuits, and measuring
instruments in voltmeter-ammeter circuits, that have sensitivity and
resolution sufficient to enable observation of at least 0.1 percent
change in the measured resistance.
(c) Maintain the dc test current at or below 15 percent of the
rated winding current.
(d) Inclusion of a stabilizing resistor Rt (see
section 3.4.2) will require higher source voltage.
(e) Disconnect the null detector (if a bridge circuit is used)
and voltmeter from the circuit before the current is switched off,
and switch off current by a suitable insulated switch.
3.4.2 Guideline for Time Constant.
(a) The following guideline is suggested for the tester as a
means to facilitate the measurement of resistance in accordance with
the accuracy requirements of section 2.0:
(b) The accurate reading of resistance Rdc may be
facilitated by shortening the time constant. This is done by
introducing a resistor Rt in series with the winding
under test in both the bridge and voltmeter-ammeter circuits as
shown in Figures 3.1 to 3.3. The relationship for the time constant
is:
[GRAPHIC] [TIFF OMITTED] TR27AP06.009
Where:
Tc is the time constant in seconds,
Ltc is the total magnetizing and leakage inductance of
the winding under test, in henries, and
Rtc is the total resistance in ohms, consisting of
Rt in series with the winding resistance Rdc
and the resistance Rs of the standard resistor in the
bridge circuit.
(c) Because Rtc is in the denominator of the
expression for the time constant, increasing the resistance
Rtc will decrease the time constant. If the time constant
in a given test circuit is too long for the resistance readings to
be stable, then a higher resistance can be substituted for the
existing Rtc, and successive replacements can be made
until adequate stability is reached.
3.5 Conversion of Resistance Measurements.
(a) Resistance measurements must be corrected, from the
temperature at which the winding resistance measurements were made,
to the reference temperature. As specified in these test procedures,
the reference temperature for liquid-immersed transformers loaded at
50 percent of the rated load is 55 [deg]C. For medium-voltage, dry-
type transformers loaded at 50 percent of the rated load, and for
low-voltage, dry-type transformers loaded at 35 percent of the rated
load, the reference temperature is 75 [deg]C.
(b) Correct the measured resistance to the resistance at the
reference temperature using equation 3-6 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.010
Where:
Rts is the resistance at the reference temperature,
Ts,
Rdc is the measured resistance at temperature,
Tdc,
Ts is the reference temperature in [deg]C,
Tdc is the temperature at which resistance was measured
in [deg]C, and
Tk is 234.5 [deg]C for copper or 225 [deg]C for aluminum.
4.0 Loss Measurement
4.1 General Considerations.
The efficiency of a transformer is computed from the total
transformer losses, which are determined from the measured value of
the no-load loss and load loss power components. Each of these two
power loss components is measured separately using test sets that
are identical, except that shorting straps are added for the load-
loss test. The measured quantities will need correction for
instrumentation losses and may need corrections for known phase
angle errors in measuring equipment and for the waveform distortion
in the test voltage. Any power loss not measured at the applicable
reference temperature must be adjusted to that reference
temperature. The measured load loss must also be adjusted to a
specified output loading level if not measured at the specified
output loading level. Test distribution transformers designed for
harmonic currents using a sinusoidal waveform (k=1).
4.2 Measurement of Power Losses.
4.2.1 No-Load Loss.
Measure the no-load loss and apply corrections as described in
section 4.4, using the appropriate test set as described in section
4.3.
4.2.2 Load Loss.
Measure the load loss and apply corrections as described in
section 4.5, using the appropriate test set as described in section
4.3.
4.3 Test Sets.
(a) The same test set may be used for both the no-load loss and
load loss measurements provided the range of the test set
encompasses the test requirements of both tests. Calibrate the test
set to national standards to meet the tolerances in Table 2.1 in
section 2.0. In addition, the wattmeter, current measuring system
and voltage measuring system must be calibrated separately if the
overall test set calibration is outside the tolerance as specified
in section 2.0 or the individual phase angle error exceeds the
values specified in section 4.5.3.
(b) A test set based on the wattmeter-voltmeter-ammeter
principle may be used to measure the power loss and the applied
voltage and current of a transformer where the transformer's test
current and voltage are within the measurement capability of the
measuring instruments. Current and voltage transformers, known
collectively as instrument transformers, or other scaling devices
such as resistive or capacitive dividers for voltage, may be used in
the above circumstance, and must be used together with instruments
to measure current, voltage, or power where the current or voltage
of the transformer under test exceeds the measurement capability of
such instruments. Thus, a test set may include a combination of
measuring instruments and instrument transformers (or other scaling
devices), so long as the current or voltage of the transformer under
test does not exceed the measurement capability of any of the
instruments.
4.3.1 Single-Phase Test Sets.
Use these for testing single-phase distribution transformers.
4.3.1.1 Without Instrument Transformers.
(a) A single-phase test set without an instrument transformer is
shown in Figure 4.1.
[[Page 25003]]
[GRAPHIC] [TIFF OMITTED] TR27AP06.011
Where:
W is a wattmeter used to measure Pnm and Plm,
the no-load and load loss power, respectively,
Vrms is a true root-mean-square (rms) voltmeter used to
measure Vr(nm) and Vlm, the rms test voltages
in no-load and load loss measurements, respectively,
Vav is an average sensing voltmeter, calibrated to
indicate rms voltage for sinusoidal waveforms and used to measure
Va(nm), the average voltage in no-load loss measurements,
A is an rms ammeter used to measure test current, especially
Ilm, the load loss current, and
(SC) is a conductor for providing a short-circuit across the output
windings for the load loss measurements.
(b) Either the primary or the secondary winding can be connected
to the test set. However, more compatible voltage and current levels
for the measuring instruments are available if for no-load loss
measurements the secondary (low voltage) winding is connected to the
test set, and for load loss measurements the primary winding is
connected to the test set. Use the average-sensing voltmeter,
Vav, only in no-load loss measurements.
4.3.1.2 With Instrument Transformers.
A single-phase test set with instrument transformers is shown in
Figure 4.2. This circuit has the same four measuring instruments as
that in Figure 4.1. The current and voltage transformers, designated
as (CT) and (VT), respectively, are added.
[GRAPHIC] [TIFF OMITTED] TR27AP06.012
4.3.2 Three-Phase Test Sets.
Use these for testing three-phase distribution transformers. Use
in a four-wire, three-wattmeter test circuit.
4.3.2.1 Without Instrument Transformers.
(a) A three-phase test set without instrument transformers is
shown in Figure 4.3. This test set is essentially the same circuit
shown in Figure 4.1 repeated three times, and the instruments are
individual devices as shown. As an alternative, the entire
instrumentation system of a three-phase test set without
transformers may consist of a multi-function analyzer.
[[Page 25004]]
[GRAPHIC] [TIFF OMITTED] TR27AP06.013
(b) Either group of windings, the primary or the secondary, can
be connected in wye or delta configuration. If both groups of
windings are connected in the wye configuration for the no-load
test, the neutral of the winding connected to the test set must be
connected to the neutral of the source to provide a return path for
the neutral current.
(c) In the no-load loss measurement, the voltage on the winding
must be measured. Therefore a provision must be made to switch the
voltmeters for line-to-neutral measurements for wye-connected
windings and for line-to-line measurements for delta-connected
windings.
4.3.2.2 With Instrument Transformers.
A three-phase test set with instrument transformers is shown in
Figure 4.4. This test set is essentially the same circuit shown in
Figure 4.2 repeated three times. Provision must be made to switch
the voltmeters for line-to-neutral and line-to-line measurements as
in section 4.3.2.1. The voltage sensors (``coils'') of the
wattmeters must always be connected in the line-to-neutral
configuration.
[GRAPHIC] [TIFF OMITTED] TR27AP06.014
[[Page 25005]]
4.3.2.3 Test Set Neutrals.
If the power source in the test circuit is wye-connected, ground
the neutral. If the power source in the test circuit is delta-
connected, use a grounding transformer to obtain neutral and ground
for the test.
4.4 No-Load Losses: Measurement and Calculations.
4.4.1 General Considerations.
Measurement corrections are permitted but not required for
instrumentation losses and for losses from auxiliary devices.
Measurement corrections are required:
(a) When the waveform of the applied voltage is non-sinusoidal;
and
(b) When the core temperature or liquid temperature is outside
the 20 [deg]C 10 [deg]C range.
4.4.2 No-Load Loss Test.
(a) The purpose of the no-load loss test is to measure no-load
losses at a specified excitation voltage and a specified frequency.
The no-load loss determination must be based on a sine-wave voltage
corrected to the reference temperature. Connect either of the
transformer windings, primary or secondary, to the appropriate test
set of Figures 4.1 to 4.4, giving consideration to section
4.4.2(a)(2). Leave the unconnected winding(s) open circuited. Apply
the rated voltage at rated frequency, as measured by the average-
sensing voltmeter, to the transformer. Take the readings of the
wattmeter(s) and the average-sensing and true rms voltmeters.
Observe the following precautions:
(1) Voltmeter connections. When correcting to a sine-wave basis
using the average-voltmeter method, the voltmeter connections must
be such that the waveform applied to the voltmeters is the same as
the waveform across the energized windings.
(2) Energized windings. Energize either the high voltage or the
low voltage winding of the transformer under test.
(3) Voltage and frequency. The no-load loss test must be
conducted with rated voltage impressed across the transformer
terminals using a voltage source at a frequency equal to the rated
frequency of the transformer under test.
(b) Adjust the voltage to the specified value as indicated by
the average-sensing voltmeter. Record the values of rms voltage, rms
current, electrical power, and average voltage as close to
simultaneously as possible. For a three-phase transformer, take all
of the readings on one phase before proceeding to the next, and
record the average of the three rms voltmeter readings as the rms
voltage value.
Note: When the tester uses a power supply that is not
synchronized with an electric utility grid, such as a dc/ac motor-
generator set, check the frequency and maintain it within 0.5 percent of the rated frequency of the transformer under
test. A power source that is directly connected to, or synchronized
with, an electric utility grid need not be monitored for frequency.
4.4.3 Corrections.
4.4.3.1 Correction for Instrumentation Losses.
Measured losses attributable to the voltmeters and wattmeter
voltage circuit, and to voltage transformers if they are used, may
be deducted from the total no-load losses measured during testing.
4.4.3.2 Correction for Non-Sinusoidal Applied Voltage.
(a) The measured value of no-load loss must be corrected to a
sinusoidal voltage, except when waveform distortion in the test
voltage causes the magnitude of the correction to be less than 1
percent. In such a case, no correction is required.
(b) To make a correction where the distortion requires a
correction of 5 percent or less, use equation 4-1. If the distortion
requires a correction to be greater than 5 percent, improve the test
voltage and re-test. Repeat until the distortion requires a
correction of 5 percent or less.
(c) Determine the no-load losses of the transformer corrected
for sine-wave basis from the measured value by using equation 4-1 as
follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.015
Where:
Pncl is the no-load loss corrected to a sine-wave basis
at the temperature (Tnm) at which no-load loss is
measured,
Pnm is the measured no-load loss at temperature
Tnm,
P1 is the per unit hysteresis loss,
P2 is the per unit eddy-current loss,
P1 + P2 = 1,
[GRAPHIC] [TIFF OMITTED] TR27AP06.016
Vr(nm) is the test voltage measured by rms voltmeter, and
Va(nm) is the test voltage measured by average-voltage
voltmeter.
(d) The two loss components (P1 and P2)
are assumed equal in value, each assigned a value of 0.5 per unit,
unless the actual measurement-based values of hysteresis and eddy-
current losses are available (in per unit form), in which case the
actual measurements apply.
4.4.3.3 Correction of No-Load Loss to Reference Temperature.
After correcting the measured no-load loss for waveform
distortion, correct the loss to the reference temperature of 20
[deg]C. If the no-load loss measurements were made between 10 [deg]C
and 30 [deg]C, this correction is not required. If the correction to
reference temperature is applied, then the core temperature of the
transformer during no-load loss measurement (Tnm) must be
determined within 10 [deg]C of the true average core
temperature. Correct the no-load loss to the reference temperature
by using equation 4-2 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.017
Where:
Pnc is the no-load losses corrected for waveform
distortion and then to the reference temperature of 20 [deg]C,
Pnc1 is the no-load losses, corrected for waveform
distortion, at temperature Tnm,
Tnm is the core temperature during the measurement of no-
load losses, and
Tnr is the reference temperature, 20 [deg]C.
4.5 Load Losses: Measurement and Calculations.
4.5.1 General Considerations.
(a) The load losses of a transformer are those losses incident
to a specified load carried by the transformer. Load losses consist
of ohmic loss in the windings due to the load current and stray
losses due to the eddy currents induced by the leakage flux in the
windings, core clamps, magnetic shields, tank walls, and other
conducting parts. The ohmic loss of a transformer varies directly
with temperature, whereas the stray losses vary inversely with
temperature.
(b) For a transformer with a tap changer, conduct the test at
the rated current and rated-voltage tap position. For a transformer
that has a configuration of windings which allows for more than one
nominal rated voltage, determine its load losses either in the
winding configuration in which the highest losses occur or in each
winding configuration in which the transformer can operate.
4.5.2 Tests for Measuring Load Losses.
(a) Connect the transformer with either the high-voltage or low-
voltage windings to the appropriate test set. Then short-circuit the
winding that was not connected to the test set. Apply a voltage at
the rated frequency (of the transformer under test) to the connected
windings to produce the rated current in the transformer. Take the
readings of the wattmeter(s), the ammeters(s), and rms voltmeter(s).
(b) Regardless of the test set selected, the following
preparatory requirements must be satisfied for accurate test
results:
(1) Determine the temperature of the windings using the
applicable method in section 3.2.1 or section 3.2.2.
(2) The conductors used to short-circuit the windings must have
a cross-sectional area equal to, or greater than, the corresponding
transformer leads, or, if the tester uses a different method to
short-circuit the windings, the losses in the short-circuiting
conductor assembly must be less than 10 percent of the transformer's
load losses.
(3) When the tester uses a power supply that is not synchronized
with an electric utility grid, such as a dc/ac motor-generator set,
follow the provisions of the ``Note'' in section 4.4.2.
4.5.3 Corrections.
4.5.3.1 Correction for Losses from Instrumentation and Auxiliary
Devices.
4.5.3.1.1 Instrumentation Losses.
Measured losses attributable to the voltmeters, wattmeter
voltage circuit and short-circuiting conductor (SC), and to the
voltage transformers if they are used, may be deducted from the
total load losses measured during testing.
4.5.3.1.2 Losses from Auxiliary Devices.
Measured losses attributable to auxiliary devices (e.g., circuit
breakers, fuses, switches) installed in the transformer, if any,
that are not part of the winding and core assembly, may be excluded
from load losses measured during testing. To exclude these losses,
either (1) measure transformer losses without the auxiliary devices
by removing or by-passing them, or (2) measure transformer losses
with the auxiliary devices connected, determine the losses
associated with the
[[Page 25006]]
auxiliary devices, and deduct these losses from the load losses
measured during testing.
4.5.3.2 Correction for Phase Angle Errors.
(a) Corrections for phase angle errors are not required if the
instrumentation is calibrated over the entire range of power factors
and phase angle errors. Otherwise, determine whether to correct for
phase angle errors from the magnitude of the normalized per unit
correction, [beta]n, obtained by using equation 4-3 as
follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.018
(b) The correction must be applied if [beta]n is
outside the limits of 0.01. If [beta]n is
within the limits of 0.01, the correction is permitted
but not required.
(c) If the correction for phase angle errors is to be applied,
first examine the total system phase angle ([beta]w -
[beta]v + [beta]c). Where the total system
phase angle is equal to or less than 12 milliradians
(41 minutes), use either equation 4-4 or 4-5 to correct
the measured load loss power for phase angle errors, and where the
total system phase angle exceeds 12 milliradians (41 minutes) use equation 4-5, as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.019
[GRAPHIC] [TIFF OMITTED] TR27AP06.020
(d) The symbols in this section (4.5.3.2) have the following
meanings:
Plc1 is the corrected wattmeter reading for phase angle
errors,
Plm is the actual wattmeter reading,
Vlm is the measured voltage at the transformer winding,
Ilm is the measured rms current in the transformer
winding,
[GRAPHIC] [TIFF OMITTED] TR27AP06.021
is the measured phase angle between Vlm and
Ilm,
[beta]w is the phase angle error (in radians) of the
wattmeter; the error is positive if the phase angle between the
voltage and current phasors as sensed by the wattmeter is smaller
than the true phase angle, thus effectively increasing the measured
power,
[beta]v is the phase angle error (in radians) of the
voltage transformer; the error is positive if the secondary voltage
leads the primary voltage, and
[beta]c is the phase angle error (in radians) of the
current transformer; the error is positive if the secondary current
leads the primary current.
(e) The instrumentation phase angle errors used in the
correction equations must be specific for the test conditions
involved.
4.5.3.3 Temperature Correction of Load Loss.
(a) When the measurement of load loss is made at a temperature
Tlm that is different from the reference temperature, use
the procedure summarized in the equations 4-6 to 4-10 to correct the
measured load loss to the reference temperature. The symbols used in
these equations are defined at the end of this section.
(b) Calculate the ohmic loss (Pe) by using equation
4-6 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.022
(c) Obtain the stray loss by subtracting the calculated ohmic
loss from the measured load loss, by using equation 4-7 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.023
(d) Correct the ohmic and stray losses to the reference
temperature for the load loss by using equations 4-8 and 4-9,
respectively, as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.024
[GRAPHIC] [TIFF OMITTED] TR27AP06.025
(e) Add the ohmic and stray losses, corrected to the reference
temperature, to give the load loss, Plc2, at the
reference temperature, by using equation 4-10 as follows:
[[Page 25007]]
[GRAPHIC] [TIFF OMITTED] TR27AP06.026
(f) The symbols in this section (4.5.3.3) have the following
meanings:
Ilm(p) is the primary current in amperes,
Ilm(s) is the secondary current in amperes,
Pe is the ohmic loss in the transformer in watts at the
temperature Tlm,
Pe(p) is the ohmic loss in watts in the primary winding
at the temperature Tlm,
Pe(s) is the ohmic loss in watts in the secondary winding
at the temperature Tlm,
Per is the ohmic loss in watts corrected to the
reference temperature,
Plc1 is the measured load loss in watts, corrected for
phase angle error, at the temperature Tlm,
Plc2 is the load loss at the reference temperature,
Ps is the stray loss in watts at the temperature
Tlm,
Psr is the stray loss in watts corrected to the reference
temperature,
Rdc(p) is the measured dc primary winding resistance in
ohms,
Rdc(s) is the measured dc secondary winding resistance in
ohms,
Tk is the critical temperature in degrees Celsius for the
material of the transformer windings. Where copper is used in both
primary and secondary windings, Tk is 234.5 [deg]C; where
aluminum is used in both primary and secondary windings,
Tk is 225 [deg]C; where both copper and aluminum are used
in the same transformer, the value of 229 [deg]C is used for
Tk,
Tk(p) is the critical temperature in degrees Celsius for
the material of the primary winding: 234.5 [deg]C if copper and 225
[deg]C if aluminum,
Tk(s) is the critical temperature in degrees Celsius for
the material of the secondary winding: 234.5 [deg]C if copper and
225 [deg]C if aluminum,
Tlm is the temperature in degrees Celsius at which the
load loss is measured,
Tlr is the reference temperature for the load loss in
degrees Celsius,
Tdc is the temperature in degrees Celsius at which the
resistance values are measured, and
N1/N2 is the ratio of the number of turns in
the primary winding (N1) to the number of turns in the
secondary winding (N2); for a primary winding with taps,
N1 is the number of turns used when the voltage applied
to the primary winding is the rated primary voltage.
5.0 Determining the Efficiency Value of the Transformer
This section presents the equations to use in determining the
efficiency value of the transformer at the required reference
conditions and at the specified loading level. The details of
measurements are described in sections 3.0 and 4.0. For a
transformer that has a configuration of windings which allows for
more than one nominal rated voltage, determine its efficiency either
at the voltage at which the highest losses occur or at each voltage
at which the transformer is rated to operate.
5.1 Output Loading Level Adjustment.
If the output loading level for energy efficiency is different
from the level at which the load loss power measurements were made,
then adjust the corrected load loss power, Plc2, by using
equation 5-1 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.028
Where:
Plc is the adjusted load loss power to the specified
energy efficiency load level,
Plc2 is as calculated in section 4.5.3.3,
Por is the rated transformer apparent power (name plate),
Pos is the specified energy efficiency load level, where
, and Pos = PorL2, and
L is the per unit load level, e.g., if the load level is 50 percent
then ``L'' will be 0.5.
5.2 Total Loss Power Calculation.
Calculate the corrected total loss power by using equation 5-2
as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.029
Where:
Pts is the corrected total loss power adjusted for the
transformer output loading specified by the standard,
Pnc is as calculated in section 4.4.3.3, and
Plc is as calculated in section 5.1.
5.3 Energy Efficiency Calculation.
Calculate efficiency ([eta]) in percent at specified energy
efficiency load level, Pos, by using equation 5-3 as
follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.030
Where:
Pos is as described and calculated in section 5.1, and
Pts is as described and calculated in section 5.2.
5.4 Significant Figures in Power Loss and Efficiency Data.
In measured and calculated data, retain enough significant
figures to provide at least 1 percent resolution in power loss data
and 0.01 percent resolution in efficiency data.
6.0 Test Equipment Calibration and Certification
Maintain and calibrate test equipment and measuring instruments,
maintain calibration records, and perform other test and measurement
quality assurance procedures according to the following sections.
The calibration of the test set must confirm the accuracy of the
test set to that specified in section 2.0, Table 2.1.
6.1 Test Equipment.
The party performing the tests shall control, calibrate and
maintain measuring and test equipment, whether or not it owns the
equipment, has the equipment on loan, or the equipment is provided
by another party. Equipment shall be used in a manner which assures
that measurement uncertainty is known and is consistent with the
required measurement capability.
6.2 Calibration and Certification.
The party performing the tests must:
(a) Identify the measurements to be made, the accuracy required
(section 2.0) and select the appropriate measurement and test
equipment;
(b) At prescribed intervals, or prior to use, identify, check
and calibrate, if needed, all measuring and test equipment systems
or devices that affect test accuracy, against certified equipment
having a known valid relationship to nationally recognized
standards; where no such standards exist, the basis used for
calibration must be documented;
(c) Establish, document and maintain calibration procedures,
including details of equipment type, identification number,
location, frequency of checks, check method, acceptance criteria and
action to be taken when results are unsatisfactory;
(d) Ensure that the measuring and test equipment is capable of
the accuracy and precision necessary, taking into account the
voltage, current and power factor of the transformer under test;
(e) Identify measuring and test equipment with a suitable
indicator or approved identification record to show the calibration
status;
(f) Maintain calibration records for measuring and test
equipment;
[[Page 25008]]
(g) Assess and document the validity of previous test results
when measuring and test equipment is found to be out of calibration;
(h) Ensure that the environmental conditions are suitable for
the calibrations, measurements and tests being carried out;
(i) Ensure that the handling, preservation and storage of
measuring and test equipment is such that the accuracy and fitness
for use is maintained; and
(j) Safeguard measuring and test facilities, including both test
hardware and test software, from adjustments which would invalidate
the calibration setting.
Appendix B to Subpart K of Part 431--Sampling Plan for Enforcement
Testing
Step 1. The number of units in the sample (m1) shall
be in accordance with Sec. Sec. 431.198(a)(4), 431.198(a)(5),
431.198(a)(6) and 431.198(a)(7) and shall not be greater than
twenty. The number of tests in the first sample (n1)
shall be in accordance with Sec. 431.198(a)(8) and shall be not
fewer than four.
Step 2. Compute the mean (Xi) of the measured energy
performance of the n1 tests in the first sample by using
equation 1 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.031
where Xi is the measured efficiency of test i.
Step 3. Compute the sample standard deviation (S1) of
the measured efficiency of the n1 tests in the first
sample by using equation 2 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.032
Step 4. Compute the standard error (SE(X1)) of the
mean efficiency of the first sample by using equation 3 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.033
Step 5. Compute the sample size discount (SSD(m1)) by
using equation 4 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.034
where m1 is the number of units in the sample, and RE is
the applicable EPCA efficiency when the test is to determine
compliance with the applicable statutory standard, or is the labeled
efficiency when the test is to determine compliance with the labeled
efficiency value.
Step 6. Compute the lower control limit (LCL1) for
the mean of the first sample by using equation 5 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.035
where t is the 2.5th percentile of a t-distribution for a sample
size of n1, which yields a 97.5 percent confidence level
for a one-tailed t-test.
Step 7. Compare the mean of the first sample (X1)
with the lower control limit (LCL1) to determine one of
the following:
(i) If the mean of the first sample is below the lower control
limit, then the basic model is in non-compliance and testing is at
an end.
(ii) If the mean is equal to or greater than the lower control
limit, no final determination of compliance or non-compliance can be
made; proceed to Step 8.
Step 8. Determine the recommended sample size (n) by using
equation 6 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.036
where S1 and t have the values used in Steps 3 and 6,
respectively. The factor
[GRAPHIC] [TIFF OMITTED] TR27AP06.037
is based on an 8-percent tolerance in the total power loss.
Given the value of n, determine one of the following:
(i) If the value of n is less than or equal to n1 and
if the mean energy efficiency of the first sample (X1) is
equal to or greater than the lower control limit (LCL1),
the basic model is in compliance and testing is at an end.
(ii) If the value of n is greater than n1, and no
additional units are available for testing, testing is at an end and
the basic model is in non-compliance. If the value of n is greater
than n1, and additional units are available for testing,
select a second sample n2. The size of the n2
sample is determined to be the smallest integer equal to or greater
than the difference n-n1. If the value of n2
so calculated is greater than 20-n1, set n2
equal to 20-n1.
Step 9. After testing the n2 sample, compute the
combined mean (X2) of the measured energy performance of
the n1 and n2 tests of the combined first and
second samples by using equation 7 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.038
Step 10. Compute the standard error (SE(X2)) of the
mean efficiency of the n1 and n2 tests in the
combined first and second samples by using equation 8 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.039
(Note that S1 is the value obtained above in Step 3.)
Step 11. Set the lower control limit (LCL2) to,
[GRAPHIC] [TIFF OMITTED] TR27AP06.040
where t has the value obtained in Step 5 and SSD(m1) is
sample size discount from Step 5. Compare the combined sample mean
(X2) to the lower control limit (LCL2) to find
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 non-compliance 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 (LCL2), the
basic model is in compliance and testing is at an end.
Manufacturer-Option Testing
If a determination of non-compliance is made in Steps 6, 7 or
11, above, the manufacturer may request that additional testing be
conducted, in accordance with the following procedures.
Step A. The manufacturer requests that an additional number,
n3, of units be tested, with n3 chosen such
that n1+n2+n3 does not exceed 20.
Step B. Compute the mean efficiency, standard error, and lower
control limit of the new combined sample in accordance with the
procedures prescribed in Steps 8, 9, and 10, above.
Step C. Compare the mean performance of the new combined sample
to the lower control limit (LCL2) to determine one of the
following:
(a) If the new combined sample mean is equal to or greater than
the lower control limit, the basic model is in compliance and
testing is at an end.
(b) If the new combined sample mean is less than the lower
control limit and the value of
n1+n2+n3 is less than 20, the
manufacturer may request that additional units be tested. The total
of all units tested may not exceed 20. Steps A, B,and C are then
repeated.
(c) Otherwise, the basic model is determined to be in non-
compliance.
[FR Doc. 06-3165 Filed 4-26-06; 8:45 am]
BILLING CODE 6450-01-P