[Federal Register Volume 84, Number 91 (Friday, May 10, 2019)]
[Proposed Rules]
[Pages 20704-20730]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-09218]



[[Page 20703]]

Vol. 84

Friday,

No. 91

May 10, 2019

Part II





 Department of Energy





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10 CFR Part 431





Energy Conservation Program: Test Procedure for Distribution 
Transformers; Proposed Rule

  Federal Register / Vol. 84 , No. 91 / Friday, May 10, 2019 / Proposed 
Rules  

[[Page 20704]]


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DEPARTMENT OF ENERGY

10 CFR Part 431

[EERE-2017-BT-TP-0055]
RIN 1904-AB39


Energy Conservation Program: Test Procedure for Distribution 
Transformers

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy.

ACTION: Notice of proposed rulemaking and request for comment.

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SUMMARY: The U.S. Department of Energy (``DOE'') proposes clarifying 
amendments to the test procedure for distribution transformers to 
revise and add definitions of certain terms, to incorporate revisions 
based on the latest versions of relevant Institute of Electrical and 
Electronics Engineers (IEEE) industry standards, and to specify the 
basis for voluntary representations at additional per-unit loads (PULs) 
and additional reference temperatures. The proposals in this NOPR are 
minor revisions that do not significantly change the test procedure. 
Therefore, none of the revisions would pose undue burden on 
manufacturers. DOE is seeking comment from interested parties on the 
proposal.

DATES: DOE will accept comments, data, and information regarding this 
notice of proposed rulemaking (NOPR) no later than July 9, 2019. See 
section V, ``Public Participation,'' for details.

ADDRESSES: Any comments submitted must identify the Test Procedure NOPR 
for Distribution Transformers and provide docket number EERE-2017-BT-
TP-0055 and/or regulatory information number (RIN) 1904-AB39. Comments 
may be submitted using any of the following methods:
    (1) Federal eRulemaking Portal: http://www.regulations.gov. Follow 
the instructions for submitting comments.
    (2) Email: [email protected]. Include 
the docket number and/or RIN in the subject line of the message.
    (3) Postal Mail: Appliance and Equipment Standards Program, U.S. 
Department of Energy, Building Technologies Program, Mailstop EE-5B, 
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: 
(202) 287-1445. If possible, please submit all items on a compact disc 
(``CD''), in which case it is not necessary to include printed copies.
    (4) Hand Delivery/Courier: Appliance and Equipment Standards 
Program, U.S. Department of Energy, Building Technologies Program, 950 
L'Enfant Plaza SW, Suite 600, Washington, DC 20024. Phone: (202) 287-
1445. If possible, please submit all items on a CD, in which case it is 
not necessary to include printed copies.
    No telefacsimilies (faxes) will be accepted. For detailed 
instructions on submitting written comments and additional information 
on the rulemaking process, see section V of this document (Public 
Participation).
    Docket: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts, comments, and other supporting 
documents/materials, is available for review at http://www.regulations.gov. All documents in the docket are listed in the 
http://www.regulations.gov index. However, some documents listed in the 
index, such as those containing information that is exempt from public 
disclosure, may not be publicly available.
    The docket web page can be found at https://www.regulations.gov/docket?D=EERE-2017-BT-TP-0055. The docket web page will contain simple 
instructions on how to access all documents, including public comments, 
in the docket. See section V for information on how to submit comments 
through http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: 
    Mr. Jeremy Dommu, U.S. Department of Energy, Office of Energy 
Efficiency and Renewable Energy, Building Technologies Program, EE-5B, 
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: 
(202) 586-9870. Email: [email protected].
    Ms. Sarah Butler, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121. 
Telephone: (202) 586-1777. Email: [email protected].
    For further information on how to submit a comment or review other 
public comments and the docket, contact the Appliance and Equipment 
Standards Program staff at (202) 287-1445 or by email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Authority and Background
    A. Authority
    B. Background
II. Synopsis of the Notice of Proposed Rulemaking
III. Discussion
    A. Rulemaking Process
    B. Scope
    C. Definitions
    1. Rectifier Transformers
    2. New Definitions
    a. Per-Unit Load
    b. Terminal
    c. Auxiliary Device
    3. Updated Definitions
    a. Low-Voltage Dry-Type Distribution Transformer
    b. Reference Temperature
    D. Updates to Industry Standards
    1. Updates to NEMA TP 2
    2. Updates to IEEE Standards
    E. Per-Unit Load Testing Requirements
    1. Multiple-PUL Weighted-Average Efficiency Metric
    2. Single-PUL Efficiency Metric
    3. Other Efficiency Metric Recommendations
    4. Voluntary Representations of Efficiency at Additional PULs
    F. Purchasing Decision
    G. Load Growth
    H. Temperature Correction
    I. Multiple Voltage Capability
    J. Other Test Procedure Topics
    1. Per-Unit Load Specification
    2. Reference Temperature Specification
    3. Measurement Location
    4. Specification for Stabilization of Current and Voltage
    5. Ambient Temperature Tolerances
    6. Field Test Equipment
    7. Harmonic Current
    8. Other Editorial Revisions
    K. Sampling, Representations, AEDMs
    L. Test Procedure Costs, Harmonization, and Other Topics
    1. Test Procedure Costs and Impact
    2. Harmonization With Industry Standards
    3. Other Test Procedure Topics
    M. Compliance Date and Waivers
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Order 12866
    B. Review Under Executive Orders 13771 and 13777
    C. Review Under the Regulatory Flexibility Act
    D. Review Under the Paperwork Reduction Act of 1995
    E. Review Under the Treasury and General Government 
Appropriations Act, 1999
    F. Review Under the National Environmental Policy Act of 1969
    G. Review Under Executive Order 13132
    H. Review Under Executive Order 12988
    I. Review Under the Unfunded Mandates Reform Act of 1995
    J. Review Under Executive Order 12630
    K. Review Under Treasury and General Government Appropriations 
Act, 2001
    L. Review Under Executive Order 13211
    M. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    N. Referenced Consensus Standards
V. Public Participation
    A. Submission of Comments
    B. Issues on Which DOE Seeks Comment
VI. Approval of the Office of the Secretary

I. Authority and Background

    DOE is authorized to establish and amend energy conservation 
standards

[[Page 20705]]

and test procedures for certain industrial equipment, including 
distribution transformers. (42 U.S.C. 6317(a)) The current DOE test 
procedures for distribution transformers appear at title 10 of the Code 
of Federal Regulations (``CFR'') 431.193 and appendix A to subpart K of 
10 CFR part 431 (herein referenced as ``appendix A''). The following 
sections discuss DOE's authority to establish and amend test procedures 
for distribution transformers, as well as relevant background 
information regarding DOE's consideration of test procedures for this 
equipment.

A. Authority

    The Energy Policy and Conservation Act of 1975, as amended 
(``EPCA'') \1\ among other things, authorizes DOE to regulate the 
energy efficiency of a number of consumer products and industrial 
equipment. (42 U.S.C. 6291-6317) Title III, Part C \2\ of EPCA, added 
by Public Law 95-619, Title IV, Sec.  441(a), established the Energy 
Conservation Program for Certain Industrial Equipment, which sets forth 
a variety of provisions designed to improve energy efficiency. This 
equipment includes distribution transformers, the subject of this NOPR. 
(42 U.S.C. 6317(a))
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    \1\ All references to EPCA refer to the statute as amended 
through America's Water Infrastructure Act of 2018, Public Law 115-
270 (October 23, 2018).
    \2\ For editorial purposes, upon codification into the U.S. 
Code, Part C was redesignated as Part A-1.
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    Under EPCA, DOE's energy conservation program consists of four 
parts: (1) Testing, (2) labeling, (3) Federal energy conservation 
standards, and (4) certification and enforcement procedures. Relevant 
provisions of EPCA for distribution transformers include definitions 
(42 U.S.C. 6291; 42 U.S.C. 6311), energy conservation standards (42 
U.S.C. 6295; 42 U.S.C. 6317), test procedures (42 U.S.C. 6293; 42 
U.S.C. 6314), labeling provisions (42 U.S.C. 6294; 42 U.S.C. 6315), and 
the authority to require information and reports from manufacturers (42 
U.S.C. 6316).
    Federal energy efficiency requirements for covered equipment 
established under EPCA generally supersede State laws and regulations 
concerning energy conservation testing, labeling, and standards. (42 
U.S.C. 6316)
    The Federal testing requirements consist of test procedures that 
manufacturers of covered equipment must use as the basis for (1) 
certifying to DOE that their products comply with the applicable energy 
conservation standards adopted under EPCA (42 U.S.C. 6316(a); 42 U.S.C. 
6296), and (2) making representations about the efficiency of those 
products (42 U.S.C. 6314(d)). Similarly, DOE must use these test 
procedures to determine whether the products comply with any relevant 
standards promulgated under EPCA. (42 U.S.C. 6316(a); 42 U.S.C. 
6295(s))
    Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures 
DOE must follow when prescribing or amending test procedures for 
covered equipment. EPCA provides in relevant part that any test 
procedures prescribed or amended under this section must be reasonably 
designed to produce test results which measure energy efficiency, 
energy use and estimated annual operating cost of a covered equipment 
during a representative average use cycle or period of use and not be 
unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))
    In addition, if DOE determines that a test procedure amendment is 
warranted, it must publish proposed test procedures and offer the 
public an opportunity to present oral and written comments on them. (42 
U.S.C. 6314(b)) EPCA also requires that, at least once every 7 years, 
DOE evaluate test procedures for each type of covered equipment, 
including distribution transformers, to determine whether amended test 
procedures would more accurately or fully comply with the requirements 
for the test procedures to not be unduly burdensome to conduct and to 
be reasonably designed to produce test results that reflect energy 
efficiency, energy use, and estimated operating costs during a 
representative average use cycle. (42 U.S.C. 6314(a)(1)) If the 
Secretary determines that a test procedure amendment is warranted, the 
Secretary must publish proposed test procedures in the Federal 
Register, and afford interested persons an opportunity (of not less 
than 45 days' duration) to present oral and written data, views, and 
arguments on the proposed test procedures. (42 U.S.C. 6314(b)) DOE is 
publishing this NOPR to satisfy the 7-year review requirement specified 
in EPCA. (42 U.S.C. 6314(a)(1)(A))
    With respect to distribution transformers, EPCA states that the 
test procedures for distribution transformers 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)(A)) 
Further, DOE may review and revise the DOE test procedure. (42 U.S.C. 
6293(b)(10)(B))

B. Background

    DOE's existing test procedure for distribution transformers appears 
at 10 CFR 431.193 and appendix A. EPCA directed DOE to prescribe 
testing procedures for those ``distribution transformers'' for which 
DOE determines that energy conservation standards ``would be 
technologically feasible and economically justified, and would result 
in significant energy savings.'' (42 U.S.C. 6317(a)(1)) EPCA states 
that the testing procedures for distribution transformers 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)(A)) Upon establishment of the required test procedures, 
EPCA required DOE to establish standards for those distribution 
transformers for which test procedures were prescribed. (42 U.S.C. 
6317(a)(2)) DOE has established standards for distribution transformers 
at 10 CFR 431.196. 70 FR 60407 (October 18, 2005); 78 FR 23336 (Apr. 
18, 2013).
    Accordingly, DOE prescribed the test procedure for distribution 
transformers on April 27, 2006 (hereafter ``April 2006 TP final 
rule''). 71 FR 24972. In an April 2013 final rule amending the 
standards for distribution transformers (hereafter ``April 2013 ECS 
final rule''), DOE determined that the test procedures did not require 
amendment at that time, concluding that the test procedure as 
established in the April 2006 TP final rule was reasonably designed to 
produce test results that reflect energy efficiency and energy use, as 
required by 42 U.S.C. 6314(a)(2). 78 FR 23336, 23347-48 (April 18, 
2013).
    On September 22, 2017, DOE published a request for information 
(RFI) to collect data and information to inform its decision in 
satisfaction with the 7-year review requirement specified in EPCA 
(hereafter ``September 2017 TP RFI''). 82 FR 44347. In response to the 
September 2017 TP RFI, National Electrical Manufacturers Association 
(NEMA) requested an extension of the comment period. (NEMA, No. 4 at p. 
1) DOE published a notice on October 31, 2017, reopening the public 
comment period until November 6, 2017. 82 FR 50324.
    In this document, DOE is proposing amendments to the test procedure 
for distribution transformers. DOE also addresses the comments received 
in response to the September 2017 TP RFI.

[[Page 20706]]

II. Synopsis of the Notice of Proposed Rulemaking

    In this NOPR, DOE proposes to update 10 CFR 429.47, 431.192, 
431.193, 431.196 and appendix A as follows:
    (1) Explicitly specify that the test procedure is applicable only 
to distribution transformers that are subject to energy conservation 
standards,
    (2) Include new definitions for ``per-unit load,'' ``terminal'' and 
``auxiliary device,'' and updated definitions for ``low-voltage dry-
type distribution transformer'' and ``reference temperature,''
    (3) Reflect certain revisions from the latest version \3\ of the 
IEEE standards on which the DOE test procedure is based,
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    \3\ 42 U.S.C. 6314(d) generally requires that 180 days after a 
test procedure rule applicable to any covered equipment is 
prescribed under this section, a manufacturer who makes a 
representation of energy consumption of such equipment must test in 
accordance with the applicable test procedure. Any voluntary 
(optional) representations at additional PULs and/or temperatures 
would be required to fairly disclose the results of such testing.
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    (4) Incorporate other clarifying revisions based on review of the 
DOE test procedure,
    (5) Require manufacturers to use the DOE test procedure to make 
voluntary (optional) representations at additional PULs and reference 
temperatures,\4\ and
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    \4\ The existing test procedure already includes equations for 
producing representations at additional PULs and reference 
temperatures.
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    (6) Centralize the per-unit load and reference temperature 
specifications for certification to energy conservation standards and 
for voluntary representations.
    Table II.1 summarizes the proposed test procedure amendments 
compared to the current test procedure, as well as the reason for the 
change.

           Table II.1--Synopsis of the Proposed Test Procedure
------------------------------------------------------------------------
       Current DOE TP              Proposed TP           Attribution
------------------------------------------------------------------------
Current test procedure does   States explicitly     Clarification added
 not specify scope.            that the scope of     by DOE.
                               the test procedure
                               is limited to the
                               scope of the energy
                               conservation
                               standards (10 CFR
                               431.196). DTs not
                               subject to ECSs are
                               not subject to the
                               TP.
Per-unit load (PUL) is        Adds new definition   Improves consistency
 referred to in the DOE TP     for ``per-unit        and readability of
 as ``percent load,''          load'' (PUL) and      test procedure.
 ``percent of nameplate-       consolidates all
 rated load,'' ``percent of    the terms in
 the rated load,'' or ``per    subpart K of 10 CFR
 unit load level''.            part 431 to only
                               ``per-unit load''.
Does not define ``Per-unit    Adds new definitions  Reflects industry
 load,'' ``Terminal'' and      for ``Per-unit        standard definition
 ``Auxiliary device,'' which   load,''               (terminal) and
 are used in the current TP.   ``Terminal'' and      clarification added
                               ``Auxiliary           by DOE (PUL and
                               device'' based on     auxiliary device).
                               industry IEEE
                               standards and other
                               research. (10 CFR
                               431.192).
Follows four IEEE industry    Proposes amendments   Reflects industry
 standards, which contain      that reflect the      standard updates.
 general electric and          latest version of
 mechanical requirements and   the four IEEE
 methods for performing        industry standards:
 tests:                       (1) C57.12.00-2015..
(1) C57.12.00-2000..........  (2) C57.12.01-2015..
(2) C57.12.01-1998..........  (3) C57.12.90-2015..
(3) C57.12.90-1999..........  (4) C57.12.91-2011..
(4) C57.12.91-2001..........  (Throughout appendix
                               A to subpart K of
                               part 431).
Requires reporting            States explicitly     Update to reflect
 performance at the rated      that all testing      industry standards.
 frequency; however, the       under the DOE test
 rated frequency is not        procedure is to
 explicitly stated.            occur only at 60
                               Hz, consistent with
                               the frequency used
                               by the US electric
                               transmission and
                               distribution
                               system. (Appendix
                               A, sections 3.1(c),
                               4.1).
Requires determining winding  Specifies that the    Update to reflect
 resistance but does not       polarity of the       industry standards.
 specify whether the           core magnetization
 polarity of the core          be kept constant
 magnetization should be       during all
 kept constant as              resistance
 measurements are made.        readings,
                               consistent with
                               industry test
                               method. (Appendix
                               A, section
                               3.4.1(f)).
Requires the measurement of   Specifies explicitly  Update to reflect
 load and no-load loss,        that load and no-     industry standards.
 without explicitly            load loss
 specifying the connection     measurements are
 locations for measurements.   required to be
                               taken only at the
                               transformer
                               terminals.
                               (Appendix A,
                               section 3.4.1(g)-
                               (i)).
Testing with a sinusoidal     Specifies that all    Update to reflect
 waveform explicitly           transformers must     industry practice.
 specified only for            be tested using a
 transformers designed for     sinusoidal waveform
 harmonic currents.            (not just those
                               designed for
                               harmonic current).
                               (Appendix A,
                               section 4.1).
Requires that efficiency      Permits voluntary     Response to industry
 must be determined at a       representations of    comment.
 single test per-unit load     efficiency, load
 (PUL) of 50 percent for       loss and no-load
 both liquid-immersed and      loss at additional
 MVDT distribution             PULs and/or
 transformers, and at a        reference
 single test PUL of 35         temperature, using
 percent for LVDT              the DOE TP. Does
 distribution transformers.    not require
                               certification to
                               DOE of any
                               voluntary
                               representations.
                               (Appendix A, new
                               section 7).
Specifies PUL and reference   Centralizes the PUL   Improves readability
 temperature specifications    and reference         of test procedure.
 for certification to energy   temperature
 conservation standards in     specifications,
 multiple locations            both for the
 throughout appendix A.        certification to
                               energy conservation
                               standards and for
                               use with a
                               voluntary
                               representation.
                               (Appendix A, new
                               sections 2.1 and
                               2.2).
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[[Page 20707]]

    DOE has tentatively determined that the proposed updates would not 
change measured values used for certifying compliance with existing 
energy conservation standards for distribution transformers or pose 
undue test burden. DOE's proposed actions are addressed in detail in 
section III of this document.

III. Discussion

    The following sections focus on certain aspects of DOE's test 
procedure, including rulemaking process, scope and definitions, 
revisions based on industry standards, per-unit load (PUL) testing 
requirements, purchasing decision, load growth, temperature correction, 
multiple voltage capabilities, other test procedure issues and updates, 
sampling, representations and alternate efficiency determination method 
(AEDM), test procedure costs and harmonization, and compliance date and 
waivers. The proposals in this NOPR are minor revisions that do not 
significantly change the test procedure. Therefore, none of the 
revisions would increase burden on manufacturers. Relevant comments 
received in response to the September 2017 TP RFI are addressed in the 
appropriate sections in the following discussion. Table III.1 includes 
the list of stakeholders that submitted comments.

       Table III.1--List of Stakeholders that Submitted Comments *
------------------------------------------------------------------------
                                          Stakeholder listing (and
         Stakeholder group             abbreviation used in this NOPR)
------------------------------------------------------------------------
Efficiency Advocates..............  American Council for an Energy-
                                     Efficiency Economy and Appliance
                                     Standards Awareness Program (ACEEE
                                     & ASAP).
Manufacturers.....................  Howard Industries, NEMA, Powersmiths
                                     International Corp. (Powersmiths),
                                     Prolec-GE.
Utilities.........................  American Public Power Association
                                     (APPA), Edison Electric Institute
                                     (EEI), National Rural Electric
                                     Cooperative Association (NRECA),
                                     Pacific Gas and Electric Company,
                                     Southern California Gas Company,
                                     Southern California Edison and San
                                     Diego Gas & Electric Company
                                     (hereafter called California
                                     Investor Owner Utilities, or CA
                                     IOUs).
Steel Producers...................  AK Steel, Metglas.
Others............................  HVOLT Inc., Babanna Suresh (Suresh),
                                     Mikro-Kod Consulting (MKC).
------------------------------------------------------------------------
* DOE received other comments from anonymous submitters that were
  unrelated to the Distribution Transformer Test Procedure and are
  therefore not addressed in this NOPR but are available for review on
  the docket. The docket web page can be found at https://www.regulations.gov/docket?D=EERE-2017-BT-TP-0055.

A. Rulemaking Process

    In response to the September 2017 TP RFI, DOE received several 
comments regarding the rulemaking process.
    EEI and APPA stated that DOE should complete work on the test 
procedure before issuing any advanced notice of proposed rulemaking 
(ANOPR) or ``no new standard'' determination for the energy 
conservation standards. (EEI, No. 16 at p. 2; APPA, No. 24 at p. 1) DOE 
notes that for rulemakings related to covered equipment, it generally 
seeks to follow the process outlined in 10 CFR part 430 subpart C 
appendix A, Procedures, Interpretations and Policies for Consideration 
of New or Revised Energy Conservation Standards for Consumer Products 
(hereafter the ``Process Improvement Rule''). The Process Improvement 
Rule provides that, when appropriate and otherwise permissible, any 
necessary modifications to a test procedure will be proposed before 
issuance of an ANOPR in the standards development process, and a final 
test procedure modifying test procedures as necessary will be issued 
prior to a NOPR on proposed standards. See section 7(a) and (b). This 
document is part of the rulemaking for the test procedure for 
distribution transformers. DOE has not initiated a rulemaking regarding 
amended standards for distribution transformers, and to the extent DOE 
does propose amended standards for distribution transformers, such a 
proposal will be addressed in a separate rulemaking.
    NEMA commented that it believes there is no need for significant 
revisions to test procedures for distribution transformers. (NEMA, No. 
14 at p. 2). NRECA and APPA commented that further action to issue new 
standards or new test procedures to support new standards is not 
necessary for this product category. (NRECA, No. 22 at p. 1; APPA, No. 
24 at p. 2) Per EPCA (as discussed in section I.A of this document), 
DOE must evaluate test procedures for each type of covered equipment at 
least once every 7 years. 42 U.S.C. 6314(a)(1). Consistent with NEMA's 
comments, based on DOE's evaluation, the proposals in this NOPR are 
minor revisions that do not make significant changes to the test 
procedure. Therefore, the proposed amendments would have no impact to 
measured values.
    CA IOUs urged DOE to work with Institute of Electrical and 
Electronics Engineers (IEEE) and the Distribution Transformers 
subcommittee to gather the necessary data and information requested in 
the RFI. (CA IOUs, No. 18 at p. 1) In response to the September 2017 TP 
RFI, DOE received relevant information and data from multiple 
stakeholders to inform the test procedure rulemaking. The proposals 
presented in this document reflect DOE's consideration of all the 
information received in response to the RFI. Through this NOPR, DOE is 
providing further opportunity for the public to provide comments, 
information, and data on proposed amendments to the test procedure for 
distribution transformers.

B. Scope

    The applicability of the test procedure is provided in 10 CFR 
431.193, which states that ``the test procedures for measuring the 
energy efficiency of distribution transformers for purposes of EPCA are 
specified in appendix A to this subpart.'' DOE has established energy 
conservation standards for low-voltage dry-type (LVDT) distribution 
transformers, liquid-immersed distribution transformers, and medium-
voltage dry type (MVDT) distribution transformers at 10 CFR 431.196. In 
this NOPR, DOE proposes to state explicitly that the scope of the test 
procedure is limited to the scope of the distribution transformers that 
are subject to energy conservation standards. DOE proposes to modify 
text in 10 CFR 431.193 accordingly.

C. Definitions

    This notice proposes clarifying amendments to the test procedure 
for distribution transformers. A ``transformer'' is a device consisting 
of 2 or more coils of insulated wire that transfers alternating current 
by electromagnetic induction from 1 coil to another to change the 
original voltage or

[[Page 20708]]

current value. 10 CFR 431.192. A ``distribution transformer'' is 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. Id. 
The term ``distribution transformer'' does not include a transformer 
that is an autotransformer; drive (isolation) transformer; grounding 
transformer; machine-tool (control) transformer; nonventilated 
transformer; rectifier transformer; regulating transformer; sealed 
transformer; special-impedance transformer; testing transformer; 
transformer with tap range of 20 percent or more; uninterruptible power 
supply transformer; or welding transformer. Id.
    A ``liquid-immersed distribution transformer'' is a distribution 
transformer in which the core and coil assembly is immersed in an 
insulating liquid. Id. A ``low-voltage dry-type distribution 
transformer'' is a distribution transformer that has an input voltage 
of 600 volts or less; is air-cooled; and does not use oil as a coolant. 
Id. A ``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. Id.
    In this NOPR, DOE proposes additional specification to the test 
procedure scope and instructions. As part of that objective, DOE is 
proposing new definitions for two terms: ``terminal'' and ``auxiliary 
device.'' Details are provided in sections III.C.2.b and III.C.2.c of 
this document. In addition, DOE is proposing minor editorial updates to 
the following definitions: ``low-voltage dry-type distribution 
transformer'' and ``reference temperature.'' Details are provided in 
section III.C.3 of this NOPR.
1. Rectifier Transformers
    Rectifier transformers are defined in the CFR to operate at the 
fundamental frequency of an alternating-current system and are designed 
to have one or more output windings connected to a rectifier. 10 CFR 
431.192. Rectifier transformers are among the exclusions to the term 
``distribution transformer'' at 10 CFR 431.192. Because rectifier 
transformers are not classified as distribution transformers, they are 
not subject to the energy conservation standards at 10 CFR 431.196.
    Drive transformers are defined in the CFR to isolate electric 
motors from the line, accommodate the added loads of drive-created 
harmonics, and are designed to withstand the mechanical stresses 
resulting from both alternating- and direct-current motors drives. 10 
CFR 431.192. Drive transformers are among the exclusions to the term 
``distribution transformer'' at 10 CFR 431.192. Although drive and 
rectifier transformers are defined differently, they would share many 
features. First, both are isolation (i.e., not auto-) transformers. 
Second, both are typically exposed to (and must tolerate) significant 
drive-/power supply-created harmonic current. Finally, both are likely 
to include design features enabling them to bear mechanical stress 
resulting from rapid current changes that may arise from operation of 
motors and other industrial equipment.
    Suresh commented that many distribution transformers supply loads 
that may have greater harmonic current due to the ubiquity of 
electronics, which typically include rectifiers and which tend to 
produce harmonic current. Suresh stated that, as a result, it could be 
argued that most distribution-type transformers meet the present 
definition of the terms ``rectifier transformer'' or ``drive 
transformer.'' Suresh suggested that those terms be removed from the 
list of exclusions to the term ``distribution transformer.'' (Suresh, 
No. 8 at p. 1) Suresh also suggested that the definition of ``rectifier 
transformer'' be limited to transformers that supply loads that are 
composed of at least 75 percent power electronics. (Suresh, No. 9 at p. 
1)
    The definition of ``rectifier transformer'' should not be 
interpreted as broadly as the commenter suggests it could be; i.e., 
this term is not intended to describe a large number of transformers 
intended for general power distribution service. Linking a definition 
of ``rectifier transformer'' to supply of loads composed of greater 
than 75 percent power electronics would not be sufficient to designate 
a distribution transformer, as it may not be possible for a 
manufacturer to know in advance what fraction of the distribution 
transformer's load will include power electronics.
    DOE reviewed industry standards \5\ and internet-published 
manufacturer literature \6\ to identify physical attributes that could 
be used to distinguish transformers requiring design modification to 
serve large rectifiers and drives from transformers designed for 
general-purpose use. In that review, DOE did not observe feature 
combinations that could be used to reliably identify rectifier 
transformers. For example, DOE did not find a quantification of how 
much harmonic current a transformer would need to accommodate to become 
suitable for service as a rectifier transformer. Although DOE was not 
able to find a candidate replacement definition for ``rectifier 
transformer'' (or ``drive transformer'') in review of certain industry 
standards and internet-published literature, DOE is interested in 
receiving feedback on how such a definition may be identified.
---------------------------------------------------------------------------

    \5\ DOE reviewed the following industry standards:
    (1) IEEE C57.18.10-1998, ``IEEE Standard Practices and 
Requirements for Semiconductor Power Rectifier Transformers''.
    (2) IEC 61378-1:2011, ``Converter transformers--Part 1: 
Transformers for Industrial Applications''.
    (3) IEEE 100-2000, ``The Authoritative Dictionary of IEEE 
Standards Terms; Seventh Edition''.
    (4) IEC 60050,\5\ ``International Electrotechnical Vocabulary''.
    \6\ internet-published literature included product guides, 
brochures, manuals, and drawings.
---------------------------------------------------------------------------

    DOE requests comment on: (1) Whether the current definition of 
rectifier transformer is sufficiently specific, (2) if not, what 
modifications would make it sufficiently specific, and (3) whether 
partial output phase shift, harmonic current tolerance, or other 
electrical properties may be used to reliably identify rectifier 
transformers.
    DOE requests comment on: (1) Whether the current definition of 
drive transformer is sufficiently specific, (2) if not, what 
modifications would make it sufficiently specific, and (3) the level of 
technical similarity drive transformers bear to rectifier transformers.
2. New Definitions
    In this NOPR, DOE proposes to include new definitions for ``per-
unit load,'' ``terminal,'' and ``auxiliary devices.'' Section 5.1 of 
Appendix A references ``per-unit load'' in reference to calculation of 
load-losses. Appendix A references ``terminal'' in several provisions 
regarding test set-up, including in sections 3.3.1.2(c), 3.3.2, and 
4.4.2(a)(3). Section 4.4.1 of appendix A provides that measurement 
corrections are permitted but not required for losses from auxiliary 
devices. Neither ``per-unit load,'' ``terminal,'' nor ``auxiliary 
device'' is currently defined in the regulatory text. DOE's 
justification for proposing to add these terms is discussed further in 
the following sections.
a. Per-Unit Load
    A distribution transformer is regularly operated in-service at load 
levels less than the full rated load, based on distribution system 
design, and fluctuations in customer energy

[[Page 20709]]

demand. Throughout the test procedures and energy conservation 
standards for distribution transformers, various terms are used to 
refer to a less-than-full rated load, including ``percent load,'' 
``percent of nameplate-rated load,'' ``percent of the rated load,'' or 
``per unit load level.'' 10 CFR 431.192, 10 CFR 431.196, and appendix 
A. DOE is proposing to define a single term, ``per-unit load,'' to mean 
the fraction of rated load, and to consolidate the usage of these 
various terms to the new term ``per-unit load'' in all instances 
identified. Consolidating the terms would provide consistency 
throughout the DOE test procedure and would affirm that the different 
terms have the same meaning.
    DOE requests comment on its proposed definition of ``per-unit 
load'' and its proposal to consolidate the usage of various terms 
referring to less-than-full rated load to the single term ``per-unit 
load.''
b. Terminal
    DOE is proposing to define ``terminal'' to mean ``a conducting 
element of a distribution transformer providing electrical connection 
to an external conductor that is not part of the transformer.'' This 
definition is based on the definition for ``terminal'' in IEEE 
C57.12.80-2010, ``IEEE Standard Terminology for Power and Distribution 
Transformers.'' To clarify how losses should be measured, DOE is 
proposing to specify that load and no-load loss measurements are 
required to be taken only at the transformer terminals, as discussed 
further in Section III.J.3 of this document.
    DOE requests comment on its proposed definition of ``terminal.''
c. Auxiliary Device
    Section 4.5.3.1.2 of appendix A specifies ``during testing, 
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.'' DOE has received inquiries from 
manufacturers regarding whether certain other internal components of 
distribution transformers are required by DOE test procedures to be 
included in the loss calculation, or whether they are considered an 
auxiliary device. Beyond the listed examples of circuit breakers, 
fuses, and switches, the current test procedures do not specify which 
other components may be considered auxiliary devices. DOE is not aware 
of a prevailing industry definition for the term ``auxiliary device,'' 
as applied to distribution transformers. The language at section 
4.5.3.1.2 of appendix A provides example-based guidance regarding which 
components of a distribution transformer are regarded as auxiliary 
devices. In this NOPR, however, DOE is proposing to establish a 
definition of the term ``auxiliary device'' based on a specific list of 
all components and/or component functions that would be considered 
auxiliary devices and, therefore, be optionally excluded from 
measurement of load loss during testing.
    The auxiliary device examples listed at section 4.5.3.1.2 of 
appendix A (circuit breakers, fuses, and switches) all provide 
protective function, but do not directly aid the transformer's core 
function of supplying electrical power. Additionally, the term 
``device'' may imply a localized nature, rather than a diffuse system 
or property of the transformer.
    DOE researched commonly included components in distribution 
transformers and identified circuit breakers, fuses, switches, and 
surge/lightning arresters as devices which provide protective function 
and upon which the transformer does not rely to provide its primary 
function of supplying electrical power at a certain voltage. 
Accordingly, DOE is proposing to define ``auxiliary device'' to mean 
``a localized component of a distribution transformer that is a circuit 
breaker, switch, fuse, or surge/lightning arrester.''
    DOE requests comment on its proposed definition of ``auxiliary 
device,'' and whether certain components should be added or removed 
from the listed auxiliary devices and why. DOE also requests comment on 
whether it is appropriate to include functional component designations 
as part of a definition of ``auxiliary device'' and, if so, which 
functions and why.
3. Updated Definitions
a. Low-Voltage Dry-Type Distribution Transformer
    As described, the definition of ``low-voltage dry-type distribution 
transformer'' specifies that it does not use oil as a coolant, among 
other criteria. DOE is proposing to update the definition for ``low-
voltage dry-type distribution transformer'' by replacing the term 
``oil'' with ``insulating liquid'' within the definition, in 
conjunction with DOE's proposal to consolidate multiple terms to 
``insulating liquid,'' as described in section III.D.2 of this 
document. DOE is proposing this update to reflect that the term is 
inclusive of all insulating liquids, including those identified in IEEE 
C57.12.90-2015.
    DOE requests comment on its proposed updated definition of ``low-
voltage dry-type distribution transformer.''
b. Reference Temperature
    As currently defined at 10 CFR 431.192, ``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.
    DOE is proposing to update the definition for ``reference 
temperature'' by removing references to the numerical temperature 
values required for certification with energy conservation standards. 
DOE proposes to retain the conceptual definition of reference 
temperature and to instead rely on appendix A to specify the numerical 
temperature values. As proposed, ``reference temperature'' would mean 
the temperature at which the transformer losses are determined, and to 
which such losses must be corrected if testing is done at a different 
point. This proposal would allow use of the term reference temperature 
outside the context of conditions required for certification with 
energy conservation standards (i.e., voluntary representations at 
additional temperature values, as described in section III.E.4 of this 
document).
    DOE requests comment on its proposed updated definition of 
``reference temperature.''

D. Updates to Industry Testing Standards

    The current DOE test procedure for distribution transformers is 
based on the following industry testing standards (See 71 FR 24972, 
24982 (April 27, 2006)):

 NEMA TP 2-1998, ``Standard Test Method for Measuring the 
Energy Consumption of Distribution Transformers'' (NEMA TP 2-1998)
 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''
 IEEE C57.12.91-2001, ``IEEE Standard Test Code for Dry-Type 
Distribution and Power Transformers''

[[Page 20710]]

 IEEE C57.12.00-2000, ``IEEE Standard General Requirements for 
Liquid-Immersed Distribution, Power and Regulating Transformers''
 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''

In addition, the DOE test procedure also incorporates relevant parts of 
NEMA TP 2-2005, which also references the aforementioned IEEE industry 
standards. DOE determined that basing the procedure on multiple 
industry standards, as opposed to adopting an industry test procedure 
(or procedures) without modification, was necessary to provide the 
detail and accuracy required for the Federal test procedure, with the 
additional benefit of providing manufacturers the Federal test 
procedure in a single reference. 71 FR 24972, 24982 (April 27, 2006).
    In the September 2017 TP RFI, DOE requested comments on the 
benefits and burdens of adopting industry standards without 
modification. 82 FR 44347, 44351 (September 22, 2017). Without 
identifying specific benefits, NEMA stated generally that there is 
benefit to adopting an industry standard, but if doing so, DOE should 
limit the reference to the measurement of losses and retain DOE's 
existing calculation for efficiency. (NEMA, No. 14 at p. 9) As stated, 
DOE has already based the current test procedure on industry standards 
developed by NEMA and IEEE. Additionally, if DOE were to adopt an 
industry standard without modification, the resulting changes to the 
test procedure could require manufacturers to retest and recertify, 
because such an incorporation by reference (IBR) would require updating 
a majority of the current test procedure. At this time, DOE is not 
proposing to incorporate industry standards into its test procedures 
for distribution transformers.
1. Updates to NEMA TP 2
    Since the April 2006 TP final rule, NEMA has rescinded NEMA TP 2-
2005.\7\ DOE received one comment regarding the withdrawal; Suresh 
commented that because NEMA TP 2 was rescinded, it should not be used 
as a reference for determining efficiency for distribution 
transformers. Suresh also stated that the current IEEE/ANSI C57.12.00, 
C57.12.90 and C57.12.91 are adequate for testing. (Suresh, No. 9 at p. 
1)
---------------------------------------------------------------------------

    \7\ Standard Test Method for measuring the energy consumption of 
distribution transformers, available at: https://www.nema.org/Standards/Pages/Standard-Test-Method-for-Measuring-the-Energy-Consumption-of-Distribution-Transformers.aspx.
---------------------------------------------------------------------------

    EPCA requires that DOE base the test procedure on NEMA TP 2-1998. 
(42 U.S.C. 6293(b)(10)(A)) As discussed in the previous section, the 
DOE test procedure is based on NEMA TP 2-1998, NEMA TP 2-2005, as well 
as four widely used IEEE standards, i.e., IEEE.C57.12.00, IEEE 
C57.12.01, IEEE C57.12.90 and IEEE C57.12.91. See 71 FR 24972, 24982 
(April 27, 2006). In addition, these IEEE standards, are all referenced 
standards in NEMA TP 2-2005. Therefore, even though the DOE test 
procedure is based on NEMA TP 2-1998 and NEMA TP 2-2005, because the 
DOE test procedure also follows the appropriate IEEE standards, DOE 
finds that the current stand-alone test procedure is still appropriate.
2. Updates to IEEE Standards
    As discussed previously in this section, the DOE test procedure 
mirrors four widely used IEEE industry standards.\8\ IEEE develops and 
maintains a large number of standards for a broad range of electrical, 
electronic, and communications equipment and protocols. Since the April 
2006 TP final rule, all of the four IEEE standards have been updated. 
The latest versions of the IEEE standards include IEEE C57.12.90-2015, 
IEEE C57.12.91-2011, IEEE C57.12.00-2015, and IEEE C57.12.01-2015. 
Table III.2 provides a list of old and new versions of each of these 
IEEE standards.
---------------------------------------------------------------------------

    \8\ The distribution transformers industry refers to these 
documents as ``standards'' because they reflect standardized, 
consensus-based methods of designing, constructing, naming, rating, 
and measuring performance of distribution transformers. This use of 
the term ``standards'' contrasts with that of DOE's Appliance 
Standards Program use of the term ``standards'' to refer to a 
minimum energy efficiency (or maximum energy consumption) 
requirement. These IEEE standards do not contain minimal energy 
thresholds or requirements.

        Table III.2--IEEE Industry Standards Versions and Summary
------------------------------------------------------------------------
                         Old version     New version
    IEEE standard          (year)          (year)           Content
------------------------------------------------------------------------
C57.12.00............            2000            2015  General
                                                        electrical and
                                                        mechanical
                                                        requirements for
                                                        liquid-immersed
                                                        distribution
                                                        transformers.
C57.12.01............            1998            2015  General
                                                        electrical and
                                                        mechanical
                                                        requirements for
                                                        dry-type
                                                        distribution
                                                        transformers.
C57.12.90............            1999            2015  Methods for
                                                        performing tests
                                                        specified in
                                                        C57.12.00 and
                                                        others for
                                                        liquid-immersed
                                                        distribution
                                                        transformers.
C57.12.91............            2001            2011  Methods for
                                                        performing tests
                                                        specified in
                                                        C57.12.01 and
                                                        others for dry-
                                                        type
                                                        distribution
                                                        transformers.
------------------------------------------------------------------------

    DOE reviewed the updated IEEE standards to determine whether any of 
the updates should be incorporated into the DOE test procedure. The 
four IEEE standards are not relevant to the DOE test procedure in their 
entirety, as they include specifications and test methods beyond those 
required to measure efficiency, such as test methods for polarity, 
phase-relation, dielectric, and audible sound-level. These industry 
standards do not contain minimum energy efficiency (or maximum energy 
consumption) requirements. DOE performed the review as follows: (1) DOE 
identified the sections of the IEEE industry standards that form the 
basis of the DOE test procedure, (2) DOE compared those sections 
between the old and new versions of the IEEE industry standards, and 
(3) DOE determined which of the changes were editorial versus which 
could be improvements to the DOE test procedure.
    The IEEE C57.12.00 and IEEE C57.12.01 standards include general 
electrical and mechanical requirements and specify test methods for 
liquid-immersed and dry-type distribution transformers, by referring to 
the test methods in IEEE C57.12.90 and IEEE C57.12.91, respectively. 
Sections 5, 8, and 9 of IEEE C57.12.90-2015 and IEEE C57.12.91-2011 
provide the resistance measurements, the no-load loss test, and the 
load loss test, respectively, which provide the basis for the DOE test 
procedure. In general, DOE did not find major changes in sections 5, 8, 
and 9 between IEEE C57.12.90-2015 and IEEE C57.12.91-2011, and IEEE 
C57.12.90-1999 and IEEE C57.12.91-2001, respectively. DOE did identify 
certain updates that would provide

[[Page 20711]]

supplemental detail to the current DOE test procedure and that reflect 
current industry practice in conducting the test procedure. Therefore, 
the adoption of these updates would further improve the DOE test 
procedure consistent with industry practice. Table III.3 summarizes the 
proposed updates.

          Table III.3--Proposed Updates Based on IEEE Standards
------------------------------------------------------------------------
                                          Proposed update based on IEEE
                 Topic                              standards
------------------------------------------------------------------------
Consolidating the Terms ``Oil,''         Replace the term ``oil'' and
 ``Transformer Liquid,'' and              ``transformer liquid'' with
 ``Insulating Liquid''.                   ``insulating liquid'' in 10
                                          CFR 431.192 and appendix A to
                                          reflect that the term is
                                          inclusive of all insulating
                                          liquids, including those
                                          identified in IEEE C57.12.90-
                                          2015.
Stability Requirement for Resistance     Specify, consistent with IEEE
 Measurement.                             C57.12.90-2015, that
                                          resistance measurements are
                                          considered stable if the top
                                          insulating liquid temperature
                                          does not vary more than 2
                                          [deg]C in a one-hour period.
                                          (Appendix A, section
                                          3.2.1.2(b)).
Automatic Recording of Data............  Require automatic recording of
                                          data, as required in IEEE
                                          C57.12.90-2015 and IEEE
                                          C57.12.91-2011, using a
                                          digital data acquisition
                                          system. (Appendix A, section
                                          4.4.2(b)).
Temperature Test System Accuracy.......  Relax the temperature test
                                          system accuracy requirements
                                          to be within 1.5
                                          [deg]C for liquid-immersed
                                          distribution transformers, and
                                          2.0 [deg]C for
                                          MVDT and LVDT distribution
                                          transformers, as specified in
                                          IEEE C57.12.00-2015 and IEEE
                                          C57.12.01-2015, respectively.
                                          (Appendix A, section 2.0).
Limits for Voltmeter-Ammeter Method....  Permit use of the voltmeter-
                                          ammeter method when the rated
                                          current of the winding is less
                                          than or equal to 1A. Neither
                                          IEEE C57.12.90-2015 nor IEEE
                                          C57.12.90-2011 restrict usage
                                          of this method to certain
                                          current ranges. (Appendix A,
                                          section 3.3.2(a)).
Number of Readings Required for          Include the requirement that a
 Resistance Measurement.                  minimum of four readings for
                                          current and voltage must be
                                          used for each resistance
                                          measurement, as specified in
                                          IEEE C57.12.90-2015. (Appendix
                                          A, section 3.3.2(b)).
Connection Locations for Resistance      Add resistance measurement
 Measurements.                            specifications for single-
                                          phase windings, wye windings
                                          and delta windings, as
                                          provided in section 5.4.1 and
                                          5.4.2 of IEEE C57.12.90-2015,
                                          and sections 5.6.1 through
                                          5.6.3 of IEEE C57.12.91-2011.
                                          (Appendix A, section 3.4.1(g)-
                                          (i)).
Test Frequency.........................  Require that all testing under
                                          the DOE test procedure is to
                                          occur only at 60 Hz. (Appendix
                                          A, sections 3.1(c), 4.1).
Polarity of Core Magnetization.........  Require that the polarity of
                                          the core magnetization be kept
                                          constant during all resistance
                                          readings. (Appendix A, section
                                          3.4.1(f)).
------------------------------------------------------------------------

    The proposed updates listed in Table III.2 align with an industry-
consensus standard, and therefore, would not increase testing burden 
because the industry-consensus standard reflects current testing 
practice. IEEE standards are voluntarily developed by industry with 
input from a range of stakeholders and are based on industry 
experience. The industry standards represent the industry's own 
position on what is the best approach to distribution transformer 
testing. Additionally, industry uses IEEE test procedures. For example, 
DOE found that municipal distribution transformer procurement contracts 
almost always require the transformer be tested in accordance with IEEE 
standards. Furthermore, several manufacturer catalogs also indicate 
that distribution transformers are tested in accordance with the 
pertinent IEEE standards.
    The proposals listed in Table III.2 provide additional detail and 
direction to the current test procedures. The proposed updates 
requiring new or additional test requirements would not contradict the 
current DOE test requirements, were they to be made final. As 
discussed, these proposed clarifications reflecting the industry 
standards are already industry practice. As such, the proposals, if 
made final, would not change current measured values. Furthermore, 
providing additional specificity would improve the repeatability of the 
test procedure.
    DOE requests comment on the proposed updates based on the latest 
version of the applicable IEEE standards for testing distribution 
transformers, and specifically regarding whether industry is already 
testing to the requirements of those IEEE standards.
    DOE requests comment on the tentative determination that each of 
the proposals do not increase test cost or burden, and that they would 
not result in different measured values than the current test 
procedure.

E. Per-Unit Load Testing Requirements

    Per-unit load (PUL) is the actual power supplied by a distribution 
transformer, divided by the distribution transformer's rated capacity. 
As discussed, it is also referred to as ``percent load,'' ``percent of 
nameplate-rated load,'' ``percent of the rated load,'' or ``per unit 
load level'' in 10 CFR 431.192, 10 CFR 431.196, and appendix A. In this 
NOPR, all instances are referred to as per-unit load, or PUL.
    The efficiency of a distribution transformer varies depending on 
the PUL at which it is operating. However, the measurements obtained by 
testing a distribution transformer at one PUL can be used to 
mathematically determine the efficiency of the transformer at other 
PULs. For certifying compliance with the energy conservation standards, 
the efficiency is determined at a PUL of 50 percent for liquid-immersed 
transformers and MVDT distribution transformers, and a PUL of 35 
percent for LVDT distribution transformers. 10 CFR 431.196 and appendix 
A. The PUL at which the efficiency of a distribution transformer is 
evaluated for compliance with the applicable energy conservation 
standard is generally referred to as the ``test PUL.'' The test 
procedure, however, does not require testing of the distribution 
transformer while operating at the test PUL. Section 5.1 of appendix A 
provides equations to calculate the efficiency of a distribution 
transformer at any PUL based on the testing of the distribution 
transformer at a single PUL.

[[Page 20712]]

Current industry practice is to test at 100 percent PUL and 
mathematically determine the efficiency at the applicable test PUL.
    The test PUL is intended to represent the typical PUL experienced 
by in-service distribution transformers. However, some complications 
exist, including: (1) A given customer may not operate the transformer 
at a single constant PUL, and (2) a transformer model may be used at 
different PULs by different customers. In the September 2017 TP RFI, 
DOE requested comments and sought information on whether the test PUL 
accurately represents in-service distribution transformer performance, 
and provides test results that reflect energy efficiency, energy use, 
and estimated operating costs during a representative average use cycle 
of an in-service transformer. 82 FR 44347, 44350 (September 22, 2017).
    In addition, so that the test procedure could better reflect how 
distribution transformers operate in service, DOE stated in the 
September 2017 TP RFI that it may consider: (1) Revising the single 
test PUL to a multiple-PUL weighted-average efficiency metric, (2) 
revising the single test PUL to an alternative single test PUL metric 
that better represents in-service PUL, or (3) maintaining current 
single test PUL specifications. DOE received several comments on this 
topic, in addition to potential other metrics for energy conservation 
standards. 82 FR 44347, 44350 (September 22, 2017).
    DOE received a number of comments stating that in-service PUL is 
diverse. (HVOLT, No. 3 at p. 16, Powersmiths, No. 11 at p. 1, NRECA, 
No. 22 at p. 2, NEMA, No. 14 at p. 2, EEI, No. 16 at p. 2, Howard 
Industries, No. 24 at p. 1) HVOLT stated that transformers are 
generally purchased in bulk and largely placed in stock to be applied 
as needed, and therefore, the same transformer may be placed in a light 
loaded or heavy loaded application. (HVOLT, No. 3 at p. 21) AK Steel 
commented that transformers of the same design operate at many 
different PULs, and when transformers are operated at higher PULs, the 
load loss will far exceed the no-load losses. (AK Steel, No. 6 at p. 1) 
NRECA commented that transformers have different efficiencies at 
different PULs, and PULs can change over the lifetime of a transformer. 
(NRECA, No. 22 at p. 2)
    Several stakeholders also submitted information showing how 
observed in-service PULs are different than what was presented by DOE 
in the September 2017 TP RFI. 82 FR 44347, 44350 (September 22, 2017). 
Suresh supported re-assessing the current test PUL requirements to 
achieve the benefits of improved efficiency at optimum cost. (Suresh, 
No. 9 at p. 1) HVOLT commented that PUL data from loading studies show 
light average loads in rural settings and loads greater than 70 percent 
in some urban settings and for some commercial and industrial 
customers. (HVOLT, No. 3 at p. 16) Summary system load information 
provided by HVOLT, and referenced by EEI, of some of California's 
Pacific Gas and Electric (PG&E) regional commercial, industrial, and 
residential customers show diversity of annual and peak load factors as 
a function of what DOE assumes is system capacity. HVOLT also stated 
that American Electric Power (AEP) and PECO customer loads are also 
similarly diverse. (HVOLT, No. 3 at p. 16; EEI, No. 16 at p. 2) Metglas 
stated that PULs of 20 percent to 30 percent are typical of residential 
distribution transformers, as reported by APPA and NRECA in a February 
2015 letter to the U.S. Environmental Protection Agency (EPA). 
(Metglas, No. 17 at p. 4) Howard Industries stated that it provides 
liquid-immersed units to rural electrical cooperatives with very light 
loading and heavy industrial customers with extremely high loading. 
(Howard Industries, No. 24 at p. 1)
    Regarding the representativeness of the California data, EEI 
reasoned that it is likely that the annual load factors of transformers 
serving residential customers in California will be lower than the load 
factors of transformers serving homes in other parts of the United 
States due to the state's utility electric efficiency programs and 
building energy codes. EEI also indicated that the PG&E data is from 
2006, and therefore does not account for the significant rise in the 
number of plug-in electric vehicles, which could further increase load 
factors. (EEI, No. 16 at pp. 2-3)
    NEMA commented that it believes that the previous DOE distribution 
transformer rulemaking's investigations in typical field loading 
practices remain relevant and as accurate as is possible given the high 
variations in field conditions.9 10 11 Additionally, NEMA 
mentioned certain IEEE studies that indicate that particular utilities 
practice very high loading levels, but that EPA's ENERGY STAR 
consideration for liquid-immersed distribution transformers showed 
several utilities lightly load their transformers, which happens mostly 
in rural electric markets. (NEMA, No. 14 at p. 2) APPA and NRECA stated 
that a ``one-size-fits-all'' energy conservation standard based on a 
single test PUL has restricted availability of the most cost-effective 
and energy efficient options. Further, APPA and NRECA stated that it is 
not possible to develop an energy conservation standard and test 
procedure that take into account the varied loading on a transformer 
(both from location to location, and on an hourly and seasonal basis). 
APPA and NRECA requested that DOE refrain from any future action with 
test procedures or energy conservation standards, stating that there 
would only be a burden (no benefit) associated with those changes. 
(APPA, No. 24 at p. 2; NRECA, No. 22 at p. 3)
---------------------------------------------------------------------------

    \9\ The result of DOE's distribution transformer load analysis 
for medium-voltage liquid-immersed distribution transformers are 
contained in the Life-cycle Cost and Payback Period spreadsheet 
tools for design lines (DL) 1 through 5 on the Forecast Cells tab. 
(available at: https://www.regulations.gov/document?D=EERE-2010-BT-STD-0048-0767)
    \10\ The result of DOE's transformer load analysis for LVDT 
distribution transformers are contained in the Life-cycle Cost and 
Payback Period spreadsheet tools for DLs 6 through 8 on the Forecast 
Cells tab. (available at: https://www.regulations.gov/document?D=EERE-2011-BT-STD-0051-0085)
    \11\ The result of DOE's transformer load analysis for MVDT 
distribution transformers are contained in the Life-cycle Cost and 
Payback Period spreadsheet tools for DL 9 through 13B on the 
Forecast Cells tab. (available at: https://www.regulations.gov/document?D=EERE-2010-BT-STD-0048-0764)
---------------------------------------------------------------------------

    DOE appreciates the data and information it received on the topic 
of in-service PULs. The data and comments received are consistent with 
DOE's understanding that the in-service PULs sustained by transformers 
are very diverse. This diversity of PUL is because the application of 
distribution transformers is itself diverse, ranging from light-loading 
to heavy-loading applications. DOE recognizes that the wide range of 
in-service conditions that transformers sustain means that the 
efficiency at the test PUL may not reflect the efficiency of any given 
transformer at its in-service PUL. The information supplied by 
stakeholders was either largely anecdotal, or limited utility customer 
meter data from which transformer loads may be inferred as a proxy. 
Both anecdotal and utility customer meter data are useful as they frame 
generally expected loading limits. Additionally, the customer load data 
contains detailed loading characteristics for small, specific 
populations. However, DOE notes that both are of limited 
representativeness. Given these factors, DOE finds the information 
available at this time for describing in-service PUL to be 
inconclusive, leaving DOE unable to demonstrate that an alternate test 
PUL is more representative than the existing test PUL.

[[Page 20713]]

1. Multiple-PUL Weighted-Average Efficiency Metric
    In the September 2017 TP RFI, DOE stated it would consider a 
multiple-PUL efficiency metric because the use of a weighted-average 
efficiency metric comprised of efficiency at more than one test PUL may 
better reflect how distribution transformers operate in service, as 
described in this document. As such, DOE requested data and information 
to inform a multiple-PUL metric. 82 FR 44347, 44350 (September 22, 
2017).
    The majority of stakeholders commented that including a multiple-
PUL weighted-average efficiency metric would be overly burdensome on 
manufacturers. (HVOLT, No. 3 at p. 24; AK Steel, No. 6 at p. 2; 
Powersmiths, No. 11 at p. 2; Prolec-GE, No. 23 at p. 1-2; Howard 
Industries, No. 24 at p. 1) Specifically, Powersmiths commented that it 
would increase test burden, be difficult to agree on appropriate test 
PULs to include, present a consumer education challenge, and 
disadvantage small business manufacturers. (Powersmiths, No. 11 at p. 
2) Prolec-GE stated that a multiple-PUL weighted-average efficiency 
metric would result in suboptimal, higher-cost designs. (Prolec-GE, No. 
23 at p. 3) Howard Industries stated that no additional constraints or 
alternate metrics should be included because it will be too burdensome 
and costly. (Howard Industries, No. 24 at p. 2)
    NEMA stated that physical testing at multiple PULs would result in 
significant technical challenges to keep winding temperatures managed 
under test conditions, adding significant complexity to the test 
procedures and introducing new sources for variation. NEMA stated that 
these conditions would be unavoidable and their impacts on testing 
would serve to further increase differences between test results and 
actual in-service conditions. Because of these challenges, NEMA 
asserted that testing at one load point is the most feasible method. 
(NEMA, No. 14 at p. 5) NEMA commented that currently, transformers are 
physically tested at 100 percent PUL and follow-on test points are 
calculated, and that this practice should be maintained. NEMA stated 
that the existing method is well-proven and well-understood by NEMA 
members and other stakeholders in the transformer industry as the best 
system to evaluate transformer performance. (NEMA, No. 14 at p. 5) NEMA 
also stated that using weighted-average loading in the application of 
energy conservation standards without consideration of how it affects 
measured efficiency values could be misleading. Adding a weighted-
average formula requirement could also deny a customer who is certain 
of their field loading level from buying the most efficient transformer 
for their application. NEMA further commented that the current test PUL 
requirements allow for sufficient flexibility in field purchasing 
decisions today. (NEMA, No. 14 at p. 5)
    ACEEE & ASAP commented that DOE should consider the benefits of 
ratings based on a weighted average of multiple load points, where 
weightings are based on expected hours of operation within bands around 
each load point. ACEEE & ASAP provided as an example, ratings based on 
the average load point (about 40 percent), and the 25th and 75th 
percentile load points (about 30 percent and 50 percent respectively), 
which they stated may improve representativeness and foster improved 
efficiency in the field. ACEEE & ASAP commented that in no case should 
DOE base ratings on extreme load conditions rarely seen in the field. 
They also commented that they understand AEDMs to be technically 
capable of supplying ratings at any load point and, therefore, that 
manufacturers should be able to certify to weighted-average ratings at 
very low additional costs. (ACEEE & ASAP, No. 15 at p. 3)
    DOE appreciates the comments received regarding the multiple-PUL 
weighted-average efficiency metric. Based on comments received, DOE has 
tentatively determined that the range of in-service PULs is large, and 
varies depending on the application and location of distribution 
transformers. DOE recognizes that depending on the procedure for 
measuring and calculating the efficiency based on multiple test PULs, a 
change of metric may increase the current test burden, due to the need 
to re-test and re-certify performance to DOE.\12\ In addition, 
consumers would need to be educated on how to interpret the new metric, 
which would not correspond to performance at any one test PUL, but 
would be based on multiple operating conditions. Lastly, available data 
describing this PUL variation is largely anecdotal and insufficient to 
show that a multiple-PUL weighted-average efficiency metric is more 
representative of in-service PUL than the existing metric. 
Specifically, a lack of information is available to determine which 
PULs would be appropriate as part of a multiple-PUL weighted efficiency 
metric, and how those PULs should be weighted. Given the drawbacks 
cited and the lack of evidence at this time to show a weighted-average 
metric is more representative than the existing metric, DOE is not 
proposing a multiple-PUL weighted-average efficiency metric.
---------------------------------------------------------------------------

    \12\ Per-unit testing costs could be identical for a multiple-
PUL metric versus the existing metric, if performance at each PUL is 
calculated from a single measurement point (rather than physical 
measurements at each PUL).
---------------------------------------------------------------------------

2. Single-PUL Efficiency Metric
    In the September 2017 TP RFI, DOE stated that for a single-PUL 
efficiency metric, it may consider either continuing to use the current 
single test PUL requirements, or revising the single test PUL to an 
alternate single test PUL, if it were to better reflect how 
distribution transformers operate in service. As such, DOE requested 
data and information to inform any changes to the metric. 82 FR 44347, 
44350 (September 22, 2017).
    A number of stakeholders commented in support of both a single-PUL 
efficiency metric and the existing test PUL requirements specified. 
(HVOLT, No. 3 at p. 21; Powersmiths, No. 11 at p. 3; NEMA, No. 14 at p. 
2; NRECA, No. 22 at p. 3; Prolec-GE, No. 23 at p. 1; Howard Industries, 
No. 24 at p. 1) Specifically, Prolec-GE commented that it has not seen 
evidence warranting a change from the current 50 percent PUL 
requirement for liquid-immersed transformers. Prolec-GE stated that it 
is aware that some utilities assumed lower loads, as demonstrated by 
their Total Owning Cost (ToC) 13 14 formulas and information 
presented during the development of the EPA ENERGY STAR program for 
liquid-filled distribution transformers; however, some are higher, 
though this is the exception. Prolec-GE stated that utilities do not 
know in advance where a transformer will be installed, and that they 
also plan for load growth. Therefore, Prolec-GE concluded that 50 
percent PUL is reasonable. (Prolec-GE, No. 23 at p. 1) Howard 
Industries stated that no additional constraints or alternate metrics 
should be included because it would be too burdensome and costly. 
(Howard Industries, No. 24 at p. 2)
---------------------------------------------------------------------------

    \13\ The Total Owning Cost is the cost savings over the lifetime 
of the product, based on the utility's no-load and load loss 
evaluation factors. ToC takes into account not only the initial 
transformer cost, but also the cost to operate and maintain the 
transformer over its lifetime. The ToC formula is provided in the 
ENERGY STAR specification for distribution transformers that is 
currently under development: (https://www.energystar.gov/products/spec/distribution_transformers_pd).
    \14\ U.S. Department of Agriculture and Rural Development, Rural 
Utility Service (RUS), Guide for Economic Evaluation of Distribution 
Transformers, 2016, Bulletin 1724D-107, https://www.rd.usda.gov/publications/regulationsguidelines/bulletins/electric.
---------------------------------------------------------------------------

    ACEEE & ASAP recommended 25 percent PUL for LVDT distribution

[[Page 20714]]

transformers, 35 percent PUL for MVDT distribution transformers and 40 
percent PUL for liquid-immersed distribution transformers, in addition 
to considering ratings based on a weighted-average PUL. ACEEE & ASAP 
stated that these values would be more representative, based on data 
provided in the RFI. (ACEEE & ASAP, No. 15 at p. 3) EEI recommended 75 
percent PUL for liquid-immersed distribution transformers, if two 
single-PUL ratings are not proposed (as discussed in section III.E.1 of 
this NOPR). (EEI, No. 16 at p. 4) Powersmiths commented that the 
current DOE test procedure at 35 percent PUL for LVDT distribution 
transformers does not reflect real world efficiency, and that field 
measurements showed most of the market either at less than 15 percent 
PUL or greater than 50 percent PUL. However, given the real-world 
variability in loading and harmonic content, Powersmiths stated that it 
would not be practical or economically viable to establish a revised 
test protocol that would capture all these scenarios, as it would be 
onerous for the whole industry to follow. (Powersmiths, No. 11 at p. 2)
    With respect to test PUL requirements, DOE considered updating the 
test PUL requirements to an alternative single test PUL if it were to 
better reflect how distribution transformers operate in service. As 
discussed in sections III.E and III.E.1, however, DOE has tentatively 
determined that the range of in-service PULs is large, and that the 
available information describing in-service PUL is inconclusive, which 
leaves DOE unable at this time to show that an alternate single test 
PUL is more representative of in-service PUL than the existing single 
test PUL. DOE recognizes that a change of metric may increase the 
current test burden (depending on the procedure for measuring and 
calculating efficiency at the new test PUL), due to the need to re-test 
and re-certify performance to DOE. Therefore, given the limitations of 
the currently available data and lack of a strong indication that an 
alternate single test PUL would be more representative than the 
existing single test PUL, DOE is not proposing to amend the test PUL 
requirements. As such, DOE has tentatively determined to maintain the 
current single test PUL requirements in appendix A, which require that 
efficiency must be determined at a single test PUL of 50 percent for 
both liquid-immersed and MVDT distribution transformers, and that 
efficiency must be determined at a single test PUL of 35 percent for 
LVDT distribution transformers.
    However, DOE agrees there is value in providing a basis for 
voluntary representations of additional performance information to 
foster better-informed decision-making by consumers. Additional 
performance information at other PULs would allow consumers to maximize 
transformer efficiency based on their needs. As such, in this NOPR, DOE 
is proposing a test procedure for voluntary representations at 
additional PULs and/or reference temperatures, which is discussed 
further in section III.E.4 of this document.
3. Other Efficiency Metric Recommendations
    In addition to the potential use of alternate efficiency metrics on 
which DOE requested comment in the September 2017 TP RFI, DOE also 
received other recommendations from stakeholders to take under 
consideration. AK Steel recommended that DOE implement an efficiency 
requirement at 100 percent PUL, in addition to the current test 
requirement. (AK Steel, No. 6 at p. 2) EEI commented that based on 
factors that could both increase and decrease transformer load, it 
supported having two PUL tests for liquid-filled transformers: One at 
the current 50 percent PUL and a second at 75 percent PUL. (EEI, No. 16 
at p. 4) Howard Industries stated that no additional constraints or 
alternate metrics should be included because it will be too burdensome 
and costly. (Howard Industries, No. 24 at p. 2)
    Metglas recommended DOE use the approach considered by EPA's ENERGY 
STAR program, where EPA proposed to expand the number of PULs that 
would be optimized to four PULs (25, 35, 50, and 65 percent), in 
addition to the ToC process.\15\ Metglas stated that better matching 
the purchased unit's actual operating PUL with optimized PULs for those 
units could result in significant energy savings. (Metglas, No. 17 at 
p. 2) Metglas commented that the addition of a 100 percent PUL only 
reduces the competitiveness of all transformers made with low core-loss 
material since, to meet the (infrequently observed) 100 percent PUL, 
all low core-loss material transformers become more expensive rather 
than being the best economic solution for many actual operating PULs. 
(Metglas, No. 17 at p. 5) NRECA advocated for the ToC process, similar 
to the EPA program, which allows individual utilities to select optimal 
designs for their systems and expected PUL. (NRECA, No. 22 at p. 3)
---------------------------------------------------------------------------

    \15\ The EPA's ENERGY STAR specification for distribution 
transformers (version 1.0) is currently under development. The final 
draft specification was published on December 9, 2016 (https://www.energystar.gov/products/spec/distribution_transformers_pd). On 
September 27, 2017, EPA published guidance on buying energy 
efficient medium-voltage liquid-immersed transformers, which 
includes recommended energy efficiency criteria at 25 percent, 35 
percent, 50 percent and 65 percent PULs, in addition to using the 
ToC equation: https://www.energystar.gov/products/avoiding_distribution_transformer_energy_waste.
---------------------------------------------------------------------------

    HVOLT stated that the advent of new low core-loss materials has 
created the opportunity for transformers with low no-load loss to carry 
greater load losses and remain compliant; the low core-loss 
distribution transformers may perform comparatively better than 
conventional-core distribution transformers at low PULs and 
comparatively worse at high PULs. (HVOLT, No. 3 at p. 22-23) HVOLT 
recommended that to limit the potential for large load losses in 
transformers built with low core-loss materials, a constraint on total 
losses at full load is warranted to ensure that highly loaded 
transformers remain efficient. Id. HVOLT suggested that total losses do 
not require any new measurements, but would simply be calculated. In 
addition, HVOLT recommended a limit which it characterized as an 
additional energy conservation standard, on full load total losses as 
``limit = 1 + 1/(0.9 x 0.5\2\) x watts'' at 50 percent PUL for medium-
voltage distribution transformers and ``limit = 1 + 1/(0.82 x 0.35\2\) 
x watts'' at 35 percent PUL for low-voltage distribution transformers. 
HVOLT stated a generous tolerance could also be applied to that limit. 
(HVOLT, No. 3 at p. 22)
    NEMA, on the other hand, stated that proposals encouraging the 
restriction of losses at high PULs are based on very simplistic 
assumptions that do not consider the real-life restrictions a design 
must meet. NEMA stated that assuming a design can be optimized to have 
the peak efficiency at the required PUL, and that the load losses can 
be indefinitely increased through greater use of low core-loss 
materials like amorphous metal, does not adequately consider other 
restrictions transformers have in real life; for example, the capacity 
of the cooling system. (NEMA, No. 14 at p. 5)
    To summarize, the recommendations for additional metrics as 
provided by commenters are: (1) Efficiency requirements at 100 percent 
PUL in addition to current DOE requirements, (2) efficiency 
requirements at 75 percent PUL in addition to current DOE requirements 
at 50 percent PUL for liquid-immersed transformers, (3) optimization at 
25, 35, 50 and 65 percent PUL, in addition to the ToC process, similar 
to EPA's ENERGY

[[Page 20715]]

STAR guidance, and (4) constraint on total losses, in addition to 
current DOE requirements. The above recommendations address issues 
beyond the test procedure, i.e., they would result in multiple 
standards applicable to a single distribution transformer.
    DOE also received comments from Powersmiths stating that customers 
incorrectly understand transformers to operate at the minimum 
efficiencies required by DOE even at operating conditions that are 
different than in the DOE test procedure. (Powersmiths, No. 11 at p. 2) 
Powersmiths commented that the current DOE test procedure should 
remain, but also require a disclaimer label or associated literature 
that the efficiency applies only under ideal linear load (i.e., at the 
DOE test PUL), and that actual efficiency may be lower. (Powersmiths, 
No. 11 at p. 3) Powersmiths stated that, if manufacturers offer 
transformers optimized for other PULs, then they should be required to 
back up their performance claims by clearly defining whatever test 
protocols are used, supported by audit and by certification to a 
recognized testing body. (Powersmiths, No. 11 at p. 3)
    As discussed in sections III.E.1 and III.E.2 of this document, any 
changes or additional metrics may increase the current test burden, due 
to the need to re-test and re-certify performance to DOE. Additionally, 
consumers would need to be educated on how to interpret any of the new 
metrics recommended in the comments above. Lastly, DOE lacks sufficient 
information on in-service PUL to support whether an alternate test PUL 
or metric would be more representative of field conditions, so as to 
justify requiring testing at that alternate test PUL. Therefore, DOE 
finds that proposing a new metric is not justified at this time.
    However, to provide manufacturers the opportunity to inform end 
users of the performance of a distribution transformer at conditions 
other than those required to demonstrate compliance with the DOE 
efficiency standard, DOE is proposing to provide explicitly for 
voluntary representation at additional PULs and reference temperatures. 
Additional representations would allow customers to better predict how 
different distribution transformers would operate under the 
individualized conditions of that customer. Further discussion on this 
proposal is provided in section III.E.4.
4. Voluntary Representations of Efficiency at Additional PULs
    DOE received one comment suggesting that public reporting of 
additional data would increase consumer information informing 
purchasing decisions. In response to the September 2017 TP RFI, MKC 
commented that rather than specify one test point, which is typically 
at rated voltage and 50 percent load, the test procedure should 
determine both no-load loss and load loss. MKC stated that the two 
values can determine the efficiency of the transformer under any 
loading condition, and that the no-load loss and load loss would be 
determined by Clause 8 and 9 from IEEE C57.12.90, or a similar test 
method. (MKC, No. 4 at p. 1)
    Manufacturers are prohibited under 42 U.S.C. 6314(d) from making 
representations respecting the energy consumption of covered equipment 
or cost of energy consumed by such equipment, unless that equipment has 
been tested in accordance with the applicable DOE test procedure and 
such representations fairly disclose the results of that testing. As 
discussed, the current DOE test procedure requires that for both 
liquid-immersed and MVDT distribution transformers, efficiency is 
determined at a single test PUL of 50 percent, and that for LVDT 
distribution transformers, efficiency is determined at a single test 
PUL of 35 percent. Section 3.5 of appendix A. In addition, efficiency 
must be determined at the reference temperature of 20 [deg]C for no-
load loss for all distribution transformers; 55 [deg]C for load loss 
for liquid-immersed distribution transformers at the required test PUL 
of 50 percent; 75 [deg]C for load loss for MVDT distribution 
transformers at the required test PUL of 50 percent; and 75 [deg]C for 
load loss for LVDT distribution transformers at the required test PUL 
of 35 percent. 10 CFR 431.192. The DOE test procedure specifies 
reference temperature requirements only at the test PULs currently 
required to comply with the energy conservation standards.
    In this NOPR, DOE is proposing amendments to the test procedure to 
permit manufacturers to make voluntary representations of additional 
performance information of distribution transformers when operated 
under conditions other than those required for compliance with the 
energy conservation standards for distribution transformers at 10 CFR 
431.196. The proposal would help consumers make better purchasing 
decisions based on their specific installation conditions. Therefore, 
DOE proposes in a new section 7 of appendix A to allow manufacturers to 
represent efficiency, no-load loss, or load loss at additional PULs 
and/or reference temperatures, as long as the equipment is also 
represented in accordance with DOE's test procedure at the mandatory 
PUL and reference temperature. When making voluntary representations, 
best practice would be for the manufacturers also to provide the PUL 
and reference temperature corresponding to those voluntary 
representations.
    Table III.4 provides a summary of the proposal for voluntary 
representations at any PUL.

                                                Table III.4--Summary of Voluntary Representation Proposal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Mandatory certified values *                             Voluntary representations (proposed)
                                 -----------------------------------------------------------------------------------------------------------------------
                                                                          Reference
                                                                         temperature                                               Reference temperature
                                         Metric         PUL (percent)   for load loss         Metric            PUL (percent)             ([deg]C)
                                                                          ([deg]C)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Liquid Immersed.................  Efficiency.........              50              55  Efficiency, load     Any..................  Any.
                                                                                        loss, no load loss.
MVDT............................                                   50              75
LVDT............................                                   35              75
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Efficiency must be determined at a reference temperature of 20 [deg]C for no-load loss for all distribution transformers.


[[Page 20716]]

    DOE requests comment on the proposal to amend the DOE test 
procedure to permit manufacturers to make voluntary representations at 
any additional PUL and/or reference temperature, and whether this would 
assist consumers in making better purchasing decisions based on their 
specific installation conditions. DOE requests comment on whether the 
current DOE test procedure would be appropriate at non-mandatory PULs 
and reference temperatures.

F. Purchasing Decision

    While a customer can specify that transformer efficiency be 
optimized to their in-service PUL, the transformer must also comply 
with the energy conservation standard at the test PUL. The lowest-cost 
transformer design would likely have an efficiency peak at or near the 
test PUL, and that the low-cost transformers would experience reduced 
efficiency when operated at PULs other than the test PUL. Therefore, 
considering there may be variation between the test PUL specified in 
the test procedure and actual in-service use, DOE requested comment on 
the extent to which efficiency is considered for transformer purchasing 
decisions.
    DOE received several comments from stakeholders indicating that 
first cost is the primary driver for purchasing decisions. HVOLT 
commented that efficiency is only considered for simple verification 
that the transformer is DOE-compliant. Beyond that, HVOLT asserted, 
purchase decisions are mostly made on price, delivery and other user 
specifications. (HVOLT, No. 3 at p. 17) AK Steel stated that it has 
consistently seen that when purchasing transformers, first cost, 
including transformer cost plus installation, is the primary driver in 
purchasing decisions. (AK Steel, No. 6 at p. 2)
    In addition, DOE received several comments stating that most 
manufacturers and customers ensure only that transformers are DOE 
compliant when considering efficiency. Specifically, AK Steel, which 
produces electrical steel used in distribution transformers, stated 
that performance exceeding the DOE energy conservation standard is not 
a consideration when AK Steel prices its electrical steel. (AK Steel, 
No. 6 at p. 2) AK Steel commented that transformer efficiency at 
current test PULs have little influence on transformer efficiency at 
higher PULs, which AK Steel states is especially apparent when lower-
cost, less-efficient windings are used. AK Steel asserts that as a 
result, users will purchase DOE-compliant transformers that have 
significantly lower efficiency than more appropriately designed units 
for in-service PULs. (AK Steel, No. 6 at p. 1)
    Metglas, which also produces electrical steel used in distribution 
transformers, suggests that by allowing those purchasing distribution 
transformers the opportunity to better match projected operating 
conditions with transformers better optimized for those conditions that 
significant energy saving could be realized. (Metglas, No. 17 at p. 2) 
Powersmiths recognized DOE's identification of the business opportunity 
for transformer manufacturers to produce application-specific 
optimization that can realize low transformer lifecycle cost to 
customers, but stated that this opportunity has been ignored by 
manufacturers. (Powersmiths, No. 11 at p. 2) NEMA stated that some 
utility customers who know their anticipated loading do seek 
information from their transformer supplier about whether a transformer 
can be designed to meet best efficiency at that PUL. (NEMA, No. 14 at 
p. 3)
    However, Powersmiths stated that despite smaller manufacturers 
having more flexibility to provide application-specific models that 
deliver increased efficiency in each targeted application, these 
manufacturers do not typically offer additional choices beyond what is 
required by the DOE test procedure. Additionally, having a multitude of 
models optimized for different applications is not compatible with the 
low cost, high volume manufacturing and distribution model, which 
drives the fewest product configurations. (Powersmiths, No. 11 at pgs. 
2-3) Powersmiths further commented that manufacturers design their 
transformers with peak efficiency at the single DOE test PUL to the 
detriment of all other operating conditions, such that they are the 
lowest cost supplier in the competitive market. (Powersmiths, No. 11 at 
p. 2) Prolec-GE similarly stated that it does not see benefit in 
representing efficiency at a level higher than the DOE minimum, because 
most customers only want assurance that the transformer is compliant. 
(Prolec-GE, No. 23 at p. 5) NEMA further stated that while a 
transformer can be designed to be optimized for PULs other than DOE's 
test PUL, it must also meet the current DOE efficiency standard, and 
the two are not necessarily the same, and in many cases, the two 
efficiency points cannot be reconciled in a feasible design and 
manageable cost. (NEMA, No. 14 at p. 3)
    DOE also received several other comments regarding other ways 
customers evaluate their purchasing decisions. NEMA stated that members 
in liquid-filled product categories seek specifications from customers 
which include ToC as a way of addressing efficiency in the purchasing 
decision process. However, NEMA stated that ToC does not guarantee that 
the resulting design will exceed the current DOE efficiency levels by 
any appreciable margin. NEMA commented that the NEMA dry-type 
manufacturers rarely experience ToC requests. NEMA stated that there is 
a niche market for high efficiency LVDT distribution transformers, but 
the size of the market is unknown to NEMA members. For MVDT 
distribution transformers, NEMA stated that efficiency does not appear 
to be a significant consideration; price and delivery remain top 
considerations. (NEMA, No. 14 at p. 3) Prolec-GE stated that 30 to 40 
percent of its customers (mostly in rural utility service and rural 
electric cooperative markets) evaluate, and half end up buying the best 
ToC choice. (Prolec-GE, No. 23 at p. 2) Prolec-GE further stated 
meeting the DOE standard at 50 percent PUL and customer ToC formula can 
be challenging without pushing first cost too high. (Prolec-GE, No. 23 
at p. 2) Howard Industries commented that approximately 50 percent of 
its utility customers are still using the ToC approach when purchasing 
liquid-immersed transformers. (Howard Industries, No. 24 at p. 1)
    DOE acknowledges that many transformers are designed such that 
their efficiency peaks at the DOE test PULs, which will allow for the 
lowest costs. DOE also acknowledges that some transformers are 
optimized at PULs other than those required by DOE's test procedure. 
DOE also notes that customers use several different methods to 
determine the appropriate distribution transformers for their 
application, including the ToC method. DOE's requirements do not 
restrict the use of any of the purchasing decision methods, as long as 
both the test procedure and standards requirements are met.
    As described previously in section III.E.4 of this NOPR, in an 
effort to provide manufacturers greater opportunity to describe 
equipment performance at additional PULs, DOE is proposing amendments 
to the DOE test procedure that would allow manufacturers to make 
voluntary representations at additional PULs and reference 
temperatures, using the DOE test procedure. Manufacturers would still 
be required to comply with the current energy conservation standards 
requirements but would be allowed to voluntarily represent their 
equipment at

[[Page 20717]]

a variety of PUL conditions. This information could be used by 
consumers to make better informed purchasing decisions based on their 
specific installation conditions.

G. Load Growth

    In the September 2017 TP RFI, DOE discussed estimates for the load 
growth of distribution transformers used in the April 2013 ECS final 
rule. 82 FR 33437, 44349. These estimates contribute to the description 
of typical loading experienced by a distribution transformer in-
service. DOE estimated a one percent annual increase over the life of 
the transformer to account for connected load growth for liquid-
immersed transformers, and no load growth over the life of LVDT and 
MVDT distribution transformers. DOE requested comments regarding the 
load growth estimate over the life of distribution transformers 
currently being installed, and how that could inform test requirements 
in the DOE test procedure. Id.
    DOE received several comments on this topic. HVOLT stated that it 
does not have any hard data on the load growth estimate over the life 
of the distribution transformer. HVOLT commented that utilities are 
generally focused on peak power demand, as non-peak loading does little 
to affect distribution system design needs, and that load growth 
normally results from new customers or loads being added to existing 
circuits. In addition, HVOLT stated that the expanded electrification 
of motor vehicles and new commercial and industrial processes are 
likely to increase the load on MVDT distribution transformers. On the 
other hand, HVOLT commented that the loads on LVDT distribution 
transformers may be relatively constant. (HVOLT, No. 13 at p. 17)
    ACEEE & ASAP commented that a 0.5 percent growth rate is consistent 
with the EIA's Annual Energy Outlook 2017 projected load growth of 0.56 
percent per year in its reference case. (ACEEE & ASAP, No. 15 at p. 2) 
EEI commented that it believes the overall trends in load could be 
increasing over time given some of the significant changes occurring in 
the electricity industry. Specifically, the trends include the 
deployment of Smart Grid technologies, the increased variability of 
distributed and renewable energy sources at different times of day in 
renewable distributed generation systems, increased deployment of 
electric transportation options, and the increased electrification of 
industrial and other operations; and asks that any change in the test 
procedure account for these changes. (EEI, No. 16 at p. 3) NRECA stated 
that it is not possible to tell if load factors over the lifetime of 
transformers will decrease due to energy efficiency or greatly increase 
due to penetration of electric vehicles and other distributed energy 
resources. (NRECA, No. 22 at p. 2)
    DOE appreciates the comments and opinions submitted on the topic of 
load growth sustained by in-service transformers. As commenters noted, 
a number of trends and factors may impact the load growth realized by 
distribution transformers and that some of these trends would have 
opposing impacts (e.g., improvements in efficiencies versus the 
increased penetration of electric vehicles). At the present, DOE does 
not have sufficient data to propose changing the current test procedure 
to account for transformer load growth. However, DOE will continue to 
examine trends in transformer load growth and may address the issue as 
necessary and feasible in any future rulemaking.

H. Temperature Correction

    DOE's current test procedure specifies temperature correction of 
measured loss values, a process that calculates the losses of a 
transformer as though its internal temperature during testing were 
equal to a ``reference'' temperature. The reference temperature 
provides a common point of comparison, so that the effect of 
temperature on efficiency is diminished. If transformers in service do 
not reach the same internal temperature (under identical operating 
conditions, including ambient temperature and PUL), temperature 
correction may weaken the ability of the test procedure to predict 
relative in-service performance. In the September 2017 TP RFI, DOE 
requested comments, data and information on whether the current 
temperature correction is appropriate or whether alternative approaches 
should be considered. 82 FR 44347, 44350 (September 22, 2017) DOE 
received several comments on the September 2017 TP RFI regarding this 
topic. All supported maintaining the current requirements.
    Several comments directly supported the current method of 
temperature correction. Howard Industries stated that the current 
method for temperature correction is appropriate and applicable. 
(Howard, No. 24 at p. 1) NEMA commented that the temperature conditions 
may vary greatly during operation, and that use of a common reference 
temperature allows the DOE test procedure to fairly compare different 
products. (NEMA, No. 14 at p. 4) Accordingly, NEMA suggested that the 
current test procedure requirements for temperature correction are 
adequate. NEMA also stated that internal temperature of a transformer 
is driven by both electrical losses and cooling ability. Cooling 
ability changes as a function of ambient temperature, which may vary 
widely even for a single design. In addition, cooling ability is 
closely coupled with design features that also affect many other 
electrical and mechanical characteristics of the unit. NEMA stated that 
as a result, developing a characteristic relationship between operating 
temperature and PUL is quite difficult. NEMA stated that maintaining 
the 75 [deg]C reference temperature provides consistency and is the 
best approach given the uncertainty [in true operating temperature]. 
(NEMA, No. 14 at p. 4) NEMA further commented that any change in 
requirements would cause performance data across current and future 
designs to become noncomparable. (NEMA, No. 14 at p. 4) NEMA also 
commented that modifications to the existing internal temperature 
correction methodology and test PUL requirement, which would require 
adjustment to temperature correction requirements, would cause 
manufacturers significant burden. (NEMA, No. 14 at p. 4)
    Other comments concurred with the general concept of temperature 
correction. HVOLT stated that temperature generally rises with load 
current to the 1.6 power under steady state conditions. (HVOLT, No. 3 
at p. 19) HVOLT further stated that temperature correction is not of 
significant concern, because even when it is performed, the true 
temperature of tested transformers is accurately measured and recorded. 
(HVOLT, No. 3 at p. 19) Howard Industries commented that temperature 
will rise with increasing PUL; winding rises are generally designed to 
meet 65 [deg]C rise at full load. (Howard Industries, No. 24 at p. 1)
    After further consideration, including the comments received, DOE 
is not proposing changes to the current temperature correction 
requirements. In response to NEMA's comment that transformer operating 
temperature is a function of heat buildup, ambient conditions, and 
transformer cooling design, DOE observes that, while it is true that no 
single reference temperature could represent all operating conditions, 
it may be possible to develop a methodology that accounts for heat 
buildup and transformer cooling design. DOE may explore the possibility 
in a future notice.

[[Page 20718]]

I. Multiple Voltage Capability

    Some distribution transformers have primary windings 
(``primaries'') and secondary windings (``secondaries'') that may each 
be reconfigured, for example either in series or in parallel, to 
accommodate multiple voltages. Some configurations may be more 
efficient than others. Such transformers are often purchased with the 
intent of upgrading the local power grid to a higher operating voltage 
and thereby reducing overall system losses.
    Section 4.5.1(b) of appendix A requires that for a transformer that 
has a configuration of windings that allows for more than one nominal 
rated voltage, the load losses must be determined either in the winding 
configuration in which the highest losses occur, or in each winding 
configuration in which the transformer can operate. Similarly, section 
5.0 of appendix A states that for a transformer that has a 
configuration of windings that allows for more than one nominal rated 
voltage, its efficiency must be determined either at the voltage at 
which the highest losses occur, or at each voltage at which the 
transformer is rated to operate. Under either testing and rating option 
(i.e., testing only the highest loss configuration, or testing all 
configurations), the winding configuration that produces the highest 
losses must be tested and consequently must comply with the applicable 
energy conservation standard.
    Whereas IEEE directs distribution transformers to be shipped with 
the windings in series,\16\ a manufacturer physically testing for DOE 
compliance may need to disassemble the unit, reconfigure the windings 
to test the configuration that produces the highest losses, test the 
unit, then reassemble the unit in its original configuration, which 
adds time and expense.
---------------------------------------------------------------------------

    \16\ Institute of Electrical and Electronics Engineers, Inc 
(IEEE); IEEE Standard General Requirements for Liquid-Immersed 
Distribution, Power, and Regulating Transformers, 2017, IEEE 
Standard C57.12.00-2015, https://standards.ieee.org/findstds/standard/C57.12.00-2015.html.
---------------------------------------------------------------------------

    NEMA stated that the majority of distribution transformers are used 
in service in the highest-voltage configuration and that some 
transformers will have slightly higher losses in the lowest-voltage 
configuration. NEMA stated that, based on its calculations, the 
difference in load loss between the as-shipped version as compared to 
the highest loss configuration is no more than two percent. NEMA 
further asserts that the difference in testing as-shipped versus 
highest-loss configuration has minimal impact in determining the 
numerical value of efficiency, and that the difference is smaller than 
the error introduced by the DOE formula for scaling load loss to the 
specified test PUL. (NEMA, No. 14 at p. 6) Prolec-GE commented that 
switching to as-shipped voltage configuration would improve reliability 
and reproducibility because it would facilitate more physical testing 
of transformers, and would improve representativeness because it would 
better align with performance experienced by users. (Prolec-GE, No. 23 
at p. 4) Prolec-GE also stated that it uses an AEDM and supports its 
continued allowance because reconfiguring transformers from the as-
shipped winding configuration would be quite costly. (Prolec-GE, No. 23 
at p. 4) Both Prolec-GE and NEMA suggested that DOE should harmonize 
with industry standards and practices by permitting testing in the as-
shipped winding configuration. (Prolec-GE, No. 23 at p. 6, NEMA, No. 14 
at p. 6)
    DOE recognizes that, for manufacturers physically testing their 
transformers, reporting losses in the same configuration in which the 
transformers are shipped, which IEEE instructs to be the in-series 
configuration, may be less burdensome than requiring testing in the 
configuration that produces the highest losses.\17\ DOE notes, however, 
that neither Prolec-GE nor NEMA provided transformer design data to 
support their claim that the difference in losses would be minimal when 
comparing between transformers rated ``as-shipped'' versus the current 
requirement that transformers be rated in their highest loss 
configuration. Conversely, the losses of different winding positions 
can vary considerably and, as a result, no single winding configuration 
will always yield the greatest loss (or lowest efficiency) for all 
distribution transformers. Manufacturers may decide to test in multiple 
or all configurations to find the highest loss configuration. DOE 
remains concerned that there is no reliable way to predict in which 
winding configuration a transformer will be operated over the majority 
of its lifetime.
---------------------------------------------------------------------------

    \17\ Ibid.
---------------------------------------------------------------------------

    Furthermore, as an alternative to physical testing, DOE provides 
for certification using an AEDM, which is a mathematical model based on 
the transformer design. 10 CFR 429.47. The shipped configuration has no 
bearing on the AEDM calculation, and an AEDM can determine the highest-
loss configuration instantly. The current requirement to test and 
certify based on the highest-loss configuration of the windings confers 
a consumer benefit by ensuring the consumer receives at least the 
tested level of performance. 71 FR 24972, 24985 (April 27, 2006). DOE 
notes that most transformers are currently certified using the AEDM.
    Further, changing the requirement of testing in the configuration 
from producing the highest losses to ``as-shipped'', may increase the 
calculated efficiency, changing the basis upon which existing energy 
conservation standards were established. The losses between different 
winding configurations can be significant, and to avoid potential 
backsliding DOE would need to amend its energy conservation standard to 
account for testing in a different configuration.\18\ This could also 
necessitate the need for manufacturers of transformers with multiple 
windings to re-test and re-certify their performance to DOE.
---------------------------------------------------------------------------

    \18\ EPCA contains what is known as an ``anti-backsliding'' 
provision, which prevents the Secretary from prescribing any amended 
standard that either increases the maximum allowable energy use or 
decreases the minimum required energy efficiency of a covered 
equipment. (42 U.S.C. 6295(o)(1); 42 U.S.C. 6316(a))
---------------------------------------------------------------------------

    Based on these considerations, DOE is not proposing to amend the 
requirement relating to winding configuration.
    DOE requests comment on secondary winding configurations. DOE also 
requests comment on the magnitude of the additional losses associated 
with the less efficient configurations as well as the relative period 
of operation in each winding configuration.

J. Other Test Procedure Topics

    In addition to the proposed updates to the DOE test procedure 
provided in the preceding sections, DOE also considered whether the 
existing test procedure would benefit from any further revisions and/or 
reorganizing. Additional issues are discussed in the following section.
1. Per-Unit Load Specification
    DOE proposes to centralize the PUL specifications, both for the 
certification to energy conservation standards and for use with a 
voluntary representation. Currently, the PUL for certification to 
energy conservation standards is specified in multiple locations, 
including 10 CFR 431.192 (definition of reference temperature), 10 CFR 
431.196, section 3.5(a) of appendix A, and section 5.1 of appendix A. 
DOE proposes to consolidate the PUL specification into one location--a 
newly proposed section 2.1 of appendix A. Additionally, DOE proposes to 
provide in the proposed section 2.1 of appendix A that the PUL 
specification can be any

[[Page 20719]]

value for purposes of voluntary representations. The consolidation 
would enhance readability of the test procedure and more clearly 
communicate DOE's PUL requirements with respect to certification to 
energy conservation standards and voluntary representations. The 
updates do not change existing test PUL requirements with respect to 
certification to energy conservation standards. Instead, the updates 
improve clarity with respect to selection of PUL for voluntary 
representations versus certification to energy conservation standards.
    DOE also proposes editorial changes to section 5.1 of appendix A to 
support the consolidated approach to PUL specification. Section 5.1 
contains equations used to calculate load-losses at any PUL. Section 
5.1 of appendix A uses language that limits its applicability to 
certification to energy conservation standards only. For example, it 
references the ``specified energy efficiency load level'' (i.e., the 
PUL required for certification to energy conservation standards) 
specifically. DOE proposes to generalize the language in this section 
to reference the PUL selected in the proposed section 2.1.
2. Reference Temperature Specification
    Similar to PUL, DOE proposes to consolidate the reference 
temperature specifications for certification to energy conservation 
standards and for the proposed voluntary representations. Currently, 
the reference temperature for certification to energy conservation 
standards is described in multiple locations, including 10 CFR 431.192 
(definition of reference temperature), section 3.5(a) of appendix A, 
and section 4.4.3.3 of appendix A. DOE proposes to consolidate the 
reference temperature specification into one location--a newly proposed 
section 2.2 of appendix A. Additionally, DOE proposes to describe in 
the proposed section 2.2 of appendix A that the reference temperature 
specification can be any value for purposes of voluntary 
representations. Similar to PUL, this consolidation would enhance 
readability of the test procedure and more clearly communicate DOE's 
reference temperature requirements with respect to certification to 
energy conservation standards or voluntary representations. The updates 
do not change existing reference temperature requirements with respect 
to certification to energy conservation standards. Instead, the updates 
improve clarity with respect to selection of reference temperature for 
voluntary representations versus certification to energy conservation 
standards.
    DOE also proposes editorial changes to section 3.5 and section 
4.4.3.3 of appendix A to support the consolidated approach to reference 
temperature specification. Section 3.5 of appendix A provides reference 
temperatures for certification to energy conservation standards. 
However, considering DOE has consolidated reference temperature 
specifications into one location (proposed section 2.2), DOE has 
removed the same specification in section 3.5 so that the section could 
be applicable to determine voluntary representations.
    Section 4.4.3.3 of appendix A provides the specifications and 
equations used for correcting no-load loss to the reference 
temperature. Specifically, the section provides an option for no 
correction if the no-load measurements were made between 10 [deg]C and 
30 [deg]C. This tolerance is only applicable for certification to 
energy conservation standards (it is a 10 [deg]C range 
around the 20 [deg]C reference temperature). For simplicity, DOE 
proposes no such tolerance for voluntary representations at additional 
reference temperatures, so that all measured values would be adjusted 
using the reference temperature correction formula. Finally, DOE 
proposes to remove any reference to a reference temperature of 20 
[deg]C so that the section would be applicable to determine voluntary 
representations.
3. Measurement Location
    DOE proposes to specify that load and no-load loss measurements are 
required to be taken only at the transformer terminals. Accordingly, in 
this NOPR, DOE has proposed a definition for ``terminal,'' as described 
in section III.C.2.b. DOE notes that section 5.4 of IEEE.C57.12.90-2015 
and section 5.6 of IEEE C57.12.91-2011 specify terminal-based load-loss 
measurements. In addition, section 8.2.4 of both IEEE.C57.12.90-2015 
and IEEE C57.12.91-2011 provides the same for no-load loss measurement. 
These documents reflect current industry practices and manufacturers 
are already measuring losses at the transformer terminals. Therefore, 
in this NOPR, DOE proposes to specify in section 4.3(c) of appendix A 
that both load loss and no-load loss measurements must be made from 
terminal to terminal.
4. Specification for Stabilization of Current and Voltage
    Section 3.3.2 and 3.3.1 of appendix A describe a voltmeter-ammeter 
method and resistance bridge methods, respectively, for measuring 
resistance. Both methods require measurements to be stable before 
determining the resistance of the transformer winding being measured. 
Specifically, the voltmeter-ammeter method in section 3.3.2(b) of 
appendix A requires that current and voltage readings be stable before 
taking simultaneous readings of current and voltage to determine 
winding resistance. For the resistance bridge methods, section 3.3.1 of 
appendix A requires the bridge be balanced (i.e., no voltage across it 
or current through it) before determining winding resistance. Both 
methods allow for a resistor to reduce the time constant of the 
circuit, but do not explicitly specify how to determine when 
measurements are stable. DOE notes that IEEE C57.12.90-2015, IEEE 
C57.12.91-2011, IEEE C57.12.00-2015, and IEEE C57.12.01-2015 do not 
specify how to determine that stabilization is reached. Section 3.4.2 
of appendix A provides related guidelines for improving measurement 
accuracy of resistance by reducing the transformer's time constant. 
However, section 3.4.2 also does not explicitly provide for the period 
of time (such as a certain multiple of the time constant) necessary to 
achieve stability. In this NOPR, DOE is seeking further information on 
how industry currently determines that measurements have stabilized 
before determining winding resistance using both voltmeter-ammeter 
method and resistance bridge methods.
    DOE requests comments regarding when, or at what number of time 
constants, stability is reached for the voltmeter-ammeter method and 
the resistance bridge method.
5. Ambient Temperature Tolerances
    In response to the September 2017 TP RFI, DOE received one comment 
concerning potential burden arising from the requirement to maintain 
the temperatures of both the testing laboratory and the transformer 
within certain ranges. Specifically, NEMA recommended that DOE increase 
the temperature tolerances when testing dry-type transformers, which 
require maintaining the laboratory ambient temperature within a range 
of 3 [deg]C for 3 hours before testing, and maintaining transformer 
internal temperature (if ventilated) or surface temperature (if sealed) 
within 2 [deg]C of the laboratory ambient temperature.
    NEMA stated that these temperature limits may be burdensome in 
laboratories that are not climate controlled, and that an alternate 
method to the temperature limits may be a development of a mathematical 
correction factor. NEMA acknowledged, however, that in the experience 
of its

[[Page 20720]]

membership, the temperature requirements generally presented little 
challenge.
    As stated, EPCA requires that DOE establish test procedures that 
are not unduly burdensome to conduct. Whereas widening tolerances of 
temperatures (or other measured parameters) may reduce testing cost, it 
may impact the reproducibility and repeatability of the test result. In 
the case of these particular temperature boundaries, that NEMA's 
membership is generally not experiencing difficulty in meeting them may 
suggest that they are appropriately sized. DOE does not have data 
regarding typical ranges of laboratory ambient temperature and, as a 
result, cannot be certain that reduction in temperature tolerance would 
not harm reproducibility, repeatability, and accuracy and cause future 
test results to become incomparable to past data. For these reasons, 
DOE is not proposing amendments to the laboratory ambient temperature 
and transformer internal temperature requirements.
    DOE seeks comment on its proposal to maintain the laboratory 
ambient and transformer internal temperature requirements with no 
changes.
6. Field Test Equipment
    MKC commented regarding potential difficulties inherent in using 
conventional test equipment with deployed, operational distribution 
transformers. MKC described and recommended alternative test equipment. 
(MKC, No. 4 at pp. 1-2) DOE observes that manufacturers and other 
parties testing distribution transformers are free to use any variety 
of equipment that meets the requirements set forth in appendix A.
7. Harmonic Current
    Harmonic current refers to electrical power at alternating current 
frequencies greater than the fundamental frequency. In electrical power 
applications, harmonic current is typically regarded as undesirable; 
nonetheless, distribution transformers in service are commonly subject 
to (and must tolerate) harmonic current of a degree that varies by 
application. Test procedures for distribution transformers at sections 
4.4.1(a) and 4.4.3.2(a) of appendix A direct use of a sinusoidal 
waveform when evaluating efficiency in distribution transformers.
    Regarding test setup, Powersmiths commented that it would not be 
practical for the test procedure to address the harmonic content 
experienced in every customer's installation. (Powersmiths, No. 11 at 
p. 2) DOE recognizes that transformers in service are subject to a 
variety of harmonic conditions, and that the test procedure must 
provide a common basis for comparison. Currently, the test procedure 
states that transformers designed for harmonic currents must be tested 
with a sinusoidal waveform (i.e., free of harmonic current), but does 
not do so for all other varieties of transformers. However, the intent 
of the test procedure is for all transformers to be tested with a 
sinusoidal waveform, as is implicit in section 4.4.1(a) of appendix A. 
To clarify this test setup requirement, DOE proposes to modify section 
4.1 of appendix A to read ``. . . Test all distribution transformers 
using a sinusoidal waveform (k=1).'' This is consistent with industry 
practice and manufacturers are already testing all distribution 
transformers using a sinusoidal waveform.
    DOE seeks comment on its proposal to modify section 4.1 of appendix 
A to read ``. . . Test all distribution transformers using a sinusoidal 
waveform (k=1).''
8. Other Editorial Revisions
    DOE proposes the following editorial updates to improve the 
readability of the test procedure and provide additional detail: (i) 
Revising ``shall'' (and a single instance of ``should'' in the 
temperature condition requirements at section 3.2.2(b)(3)) to ``must'' 
in appendix A, (ii) clarifying the instructional language for recording 
the winding temperature for dry-type transformers (section 3.2.2 of 
appendix A), (iii) separating certain sentences into enumerated clauses 
(section 3.2.2(a) of appendix A),\19\ (iv) identifying the 
corresponding resistance measurement method sections (section 3.3 of 
appendix A), (v) replacing a reference to ``uniform test method'' with 
``this Appendix'' (section 3.3 of appendix A), (vi) removing reference 
to guidelines under section 3.4.1, Required actions, of appendix A to 
clarify that section establishes requirements, (vii) specifying the 
maximum amount of time for the temperature of the transformer windings 
to stabilize (section 3.2.2(b)(4) of appendix A \20\), (viii) removing 
references to the test procedure in 10 CFR 431.196, and (ix) replacing 
any reference to accuracy requirements in ``section 2.0'' and/or 
``Table 2.0'' to ``section 2.3'' and/or ``Table 2.3,'' accordingly.
---------------------------------------------------------------------------

    \19\ Under the changes proposed in this document, section 
3.2.2(a) of appendix A would be split into section 3.2.2(a) and 
section 3.2.2(b).
    \20\ Under the changes proposed in this document, this section 
would become section 3.2.2(c)(4) of appendix A.
---------------------------------------------------------------------------

    Section 3.2.2 of appendix A requires that, for testing of both 
ventilated and sealed units, the ambient temperature of the test area 
may be used to estimate the winding temperature (rather than direct 
measurement of the winding temperature), provided a number of 
conditions are met, including the condition that neither voltage nor 
current has been applied to the unit under test for 24 hours (provided 
in section 3.2.2(b)(4) of appendix A). The same section also allows for 
the initial 24 hours to be increased to up to a maximum of an 
additional 24 hours, so as to allow the temperature of the transformer 
windings to stabilize at the level of the ambient temperature. Based on 
the requirement, the total amount of time allowed would be a maximum of 
48 hours. As such, in this NOPR, DOE proposes to specify explicitly 
that, for section 3.2.2(b)(4) of appendix A, the total maximum amount 
of time allowed is 48 hours.
    DOE is also proposing conforming amendments to the energy 
conservation standard provisions. 10 CFR 431.196 establishes energy 
conservation standards for certain distribution transformers. 
Immediately following each table of standards, a note specifies the 
applicable test PUL and DOE test procedure. For example, in 10 CFR 
431.196(a) the note reads, ``Note: All efficiency values are at 35 
percent of nameplate-rated load, determined according to the DOE Test 
Method for Measuring the Energy Consumption of Distribution 
Transformers under Appendix A to Subpart K of 10 CFR part 431.'' 
Because 10 CFR 431.193 already requires that testing be in accordance 
with appendix A, DOE proposes to remove the references to the test 
procedure in 10 CFR 431.196. DOE proposes to maintain the portion of 
the note identifying the PUL corresponding to the efficiency values, 
for continuity and clarity.
    As discussed in section III.J.1 and section III.J.2, DOE is 
proposing to clarify the PUL and reference temperature specifications 
for certification to energy conservation standards, and provide PUL and 
reference temperature specifications for voluntary representations, 
with a new section 2.1 for PUL requirements and section 2.2 for 
reference temperature requirements in appendix A. Accordingly, DOE 
proposes that the accuracy requirements previously provided in section 
2.0 be moved to section 2.3 in appendix A. In addition, DOE proposes to 
re-number Table 2.1, Test System Accuracy Requirements For Each 
Measured Quantity, to Table 2.3. Lastly, DOE proposes to update cross-

[[Page 20721]]

references in appendix A to the accuracy requirements in section 2.0 
and/or table 2.1, to section 2.3 and/or table 2.3. The cross-references 
occur in section 3.1(b), section 3.3.3, section 3.4.2(a), section 
4.3(a), section 6.0 and section 6.2 of appendix A.

K. Sampling, Representations, AEDMs

    The certification and compliance requirements for distribution 
transformers are codified at 10 CFR part 429. DOE's sampling 
requirements are provided at 10 CFR 429.47. The sampling requirements, 
among other things, state that, (1) the provisions of 10 CFR 429.11, 
General sampling requirements for the selected units to be tested, 
apply, (2) a manufacturer must use a sample of at least five units if 
more than five units have been manufactured over a span of six months 
(10 CFR 429.47(a)(2)(i)(A)), and (3) efficiency of a basic model may be 
determined through testing, in accordance with appendix A, or through 
application of an AEDM under the requirements of 10 CFR 429.70. (10 CFR 
429.47(a)(2)(i)(B))
    DOE's requirements related to AEDMs are at 10 CFR 429.70. This 
section specifies under which circumstances an AEDM may be developed, 
validated, and applied to performance ratings for certain covered 
products and equipment.
    In the September 2017 TP RFI, DOE requested feedback on the current 
sampling requirements; on whether manufacturers typically represent the 
minimum efficiency standard, the maximum efficiency allowable, or a 
different value; and regarding the usefulness of the AEDM provisions. 
82 FR 44347, 44351 (September 22, 2017) DOE received several comments 
on the September 2017 TP RFI regarding these topics.
    HVOLT commented that it believes the represented value calculations 
are useful in describing tolerance and objectives; large volumes of 
production have an easier means of achieving average performance than 
very small volumes of transformers. (HVOLT, No. 3 at p. 29) NEMA 
commented that the opportunity to use AEDM must be preserved, or burden 
will be raised for some manufacturers, and that DOE should maintain the 
status quo and afford manufacturers flexibility. (NEMA, No. 14 at p. 7) 
Howard Industries also commented that it uses the AEDM method to the 
fullest because it is too burdensome to physically test all units. 
(Howard Industries, No. 24 at p. 2) DOE appreciates stakeholders' 
comments and is not proposing changes to the AEDM provisions.
    HVOLT stated that it believes all manufacturers test each 
transformer manufactured for losses, and that normally distribution 
transformers are overdesigned to minimize the possibility of non-
compliant designs. (HVOLT, No. 3 at p. 28) Suresh stated that for units 
lower than 500 kVA, some manufacturers adopt bulk testing for a given 
rating at a time, and the average efficiency is determined, and that in 
some cases, manufacturers do not test all of their units because they 
test a statistically significant number of units to demonstrate the 
efficiency. (Suresh, No. 9 at p. 1) As discussed previously, DOE's 
sampling requirements require that for ratings developed using testing 
(rather than an AEDM) a manufacturer must use a sample of at least five 
units if more than five units have been manufactured over a span of six 
months (10 CFR 429.47(a)(2)(i)(B)), or as many as have been produced if 
five or fewer have been manufactured over a span of six months (10 CFR 
429.47(a)(2)(i)(A)).
    NEMA recommended that DOE consider providing software for 
manufacturers to help with reporting, and that this could be designed 
to contain all the raw data and the represented efficiency 
calculations. (NEMA, No. 14 at p. 8) DOE does provide product-specific 
templates for certifying basic models, which can be found on the 
following website: https://www.regulations.doe.gov/ccms/templates. 
However, DOE does not provide software for certification reporting. It 
is the manufacturer's responsibility to certify its products (or 
equipment) as required by DOE under 10 CFR part 429. Further, the 
manufacturer must decide how to represent the efficiency of a 
transformer between the limits of the energy conservation standard and 
the maximum representation allowed by 10 CFR 429.47(a)(2).
    DOE received no other comments on the current sampling, 
representation and AEDM requirements. DOE is not proposing amendments 
to the sampling and AEDM requirements.

L. Test Procedure Costs, Harmonization, and Other Topics

1. Test Procedure Costs and Impact
    EPCA requires that test procedures proposed by DOE not be unduly 
burdensome to conduct. In this NOPR, DOE proposes to amend the existing 
test procedure for distribution transformers by revising certain 
definitions, incorporating new definitions, incorporating revisions 
based on the latest versions of the IEEE industry standards, including 
provisions to allow manufacturers to use the DOE test procedure to make 
voluntary representations at additional PULs and/or reference 
temperatures, and reorganizing content among relevant sections of the 
CFR to improve readability. The proposed amendments would primarily 
provide updates and supplemental details for how to conduct the test 
procedure and do not add complexity to test conditions/setup or add 
test steps. In accordance with EPCA, DOE has tentatively determined 
that these proposed amendments would not be unduly burdensome for 
manufacturers to conduct. Further, DOE has tentatively determined that 
the proposal would not impact testing costs already experienced by 
manufacturers. DOE estimates based on a test quote from a laboratory 
that the cost for testing distribution transformers using the existing 
test procedure is approximately $400 per unit tested and that this 
figure would not change in response to the changes in this proposed 
rule. In summary, the proposals reflect and codify current industry 
practice.
    The proposed amendments would not impact the scope of the test 
procedure. The proposed amendments would not require the testing of 
distribution transformers not already subject to the test procedure at 
10 CFR 431.193 (i.e., the proposal would not require manufacturers to 
test autotransformers, drive (isolation) transformers, grounding 
transformers, machine-tool (control) transformers, nonventilated 
transformers, rectifier transformers, regulating transformers, sealed 
transformer; special-impedance transformer; testing transformer; 
transformer with tap range of 20 percent or more; uninterruptible power 
supply transformer; or welding transformer, which are presently not 
subject to testing). The proposed amendments would not alter the 
measured energy efficiency or energy use of the distribution 
transformers. Manufacturers would be able to rely on data generated 
under the current test procedure should the proposed amendments be 
finalized. Further, the amendments proposed in this document, if 
finalized, would not require the purchase of additional equipment for 
testing.
    DOE is proposing to adopt definitions for ``PUL,'' ``terminal'' and 
``auxiliary device.'' The proposed definitions are intended to provide 
additional specificity in the application of the test procedure. The 
proposed definitions match current industry application of the test 
procedure and, if finalized, would not impact the conduct of the test 
or testing costs experienced by

[[Page 20722]]

manufacturers. DOE is also proposing to specify that both load loss and 
no-load loss measurements must be made from ``terminal to terminal.'' 
Measuring losses at the transformer terminals reflects current industry 
practices. In addition, the DOE test procedure already explicitly 
requires certain measurements at the terminals; specifically, the 
kelvin bridge method for determining resistance measurements in section 
3.3.1.2(c), the voltmeter-ammeter method for determining resistance 
measurements in section 3.3.2(c), and the no-load loss test method in 
section 4.4.2(a)(3). Furthermore, taking other measurements (whose 
measurement locations are not explicit in the test procedure) at 
locations other than the terminal would yield results formed of 
mutually incongruous components, and would leave unclear what the test 
procedure was purporting to represent. Therefore, DOE initially 
concludes that the proposal to specify that both load loss and no-load 
loss measurements must be made from ``terminal to terminal'' reflects 
current practice and would not add any additional testing cost.
    DOE is proposing a number of updates to its test procedures based 
on updates to the relevant IEEE standards. In addition to proposals 
that reflect non-substantive editorial updates to the IEEE standards 
(i.e., consistent use of the term ``insulating liquid''), DOE is 
proposing to specify parameters for determining stability when making 
resistance measurements, explicitly require the automatic recording of 
data, specify the number of readings required for resistance 
measurement, specify the connection locations for resistance 
measurements, explicitly state the required test frequency, and require 
the polarity of the core magnetization be kept constant during all 
resistance readings. These proposed revisions, which are based on 
updates to the IEEE standards, reflect industry consensus and current 
practice. As such, these proposed revisions, if made final, would not 
impact test costs.
    DOE is proposing an amendment to the test procedures to permit 
manufacturers to make voluntary representations of the performance 
(i.e., efficiency, load loss, no load loss) of distribution 
transformers at conditions other than those required for compliance 
testing (i.e., at additional PULs and manufacturer selected reference 
temperature). Under DOE's proposal in this document, manufacturers 
would be permitted to make representations using the DOE test procedure 
regarding the performance of distribution transformers under a wider 
range of operating conditions. The additional representations would be 
voluntary.
    DOE estimates that if a manufacturer chose to make such voluntary 
representations, no additional testing cost would be incurred because 
the voluntary representations could be determined mathematically, 
without any additional testing. As discussed previously, manufacturers 
typically test distribution transformers at 100 percent PUL; 
performance at other PULs (including the PULs required for compliance 
with the energy conservation standards) is calculated mathematically. 
Appendix A provides equations \21\ that manufacturers can use to (1) 
calculate no-load and load losses at any reference temperature and (2) 
calculate load losses at any PUL. These equations are currently used to 
calculate performance at the DOE-required conditions, but these same 
equations can also be used to calculate performance at additional 
conditions (of PULs and reference temperatures) for any voluntary 
representations, without the need to conduct additional testing.
---------------------------------------------------------------------------

    \21\ Equations are provided in section 5.1, section 4.4.3.3, and 
section 4.5.3.3 of appendix A.
---------------------------------------------------------------------------

    A manufacturer could choose to re-test rather than mathematically 
determine the values for voluntary representations at other PULs or 
reference temperatures. However, the proposed provision regarding 
voluntary representations does not necessitate additional testing, were 
a manufacturer to choose to make voluntary representations. In 
addition, DOE is not requiring any certification or reporting of 
voluntary representations. For these reasons, no additional costs or 
test burden would be incurred for voluntary representations.
    In addition, DOE is also proposing to centralize the PUL and 
reference temperature specifications in appendix A, both for the 
certification to energy conservation standards and for use with a 
voluntary representation. The updates are not substantive and do not 
change existing test PUL requirements with respect to certification to 
energy conservation standards. Rather, the consolidation would enhance 
readability of the test procedure and more clearly communicate DOE's 
PUL requirements with respect to certification to energy conservation 
standards and voluntary representations.
    The other proposed amendments are mainly clerical or editorial in 
nature, and if finalized, they would not impact the measured test 
results or impact the test costs.
    DOE requests comment on its understanding of the impact and 
associated costs of the proposed test procedure. To the extent 
commenters believe that manufacturers would not be able to rely on data 
generated under the current test procedure should the proposed 
amendments be finalized, DOE requests comment on the potential 
associated costs.
2. Harmonization With Industry Standards
    As discussed in section III.D, the test procedure for distribution 
transformers at appendix A mirrors language contained in several 
industry standards: NEMA TP 2-1998; IEEE C57.12.90-1999; IEEE 
C57.12.91-2001; IEEE C57.12.00-2000; and IEEE C57.12.01-1998. DOE notes 
that when establishing the test procedure for distribution 
transformers, DOE determined that basing the procedure on multiple 
industry standards, as opposed to adopting an industry test procedure 
(or procedures) without modification, was necessary to provide the 
detail and accuracy required for the DOE test procedure, with the 
additional benefit of providing manufacturers the DOE test procedure in 
a single reference. As such, DOE relied heavily on the techniques and 
methods from NEMA TP 2-1998, NEMA TP 2-2005 and the four IEEE standards 
in developing the DOE test procedure. Both versions of NEMA TP 2 
reference the IEEE standards as part of that industry test procedure. 
Specifically, the IEEE standards provide the test system accuracy 
requirements, resistance measurement test methods, and load loss and 
no-load loss test methods for both NEMA TP 2-1998 and NEMA TP 2-2005. 
Although both versions of NEMA TP 2 were designed to be a standard that 
extracts and presents pertinent parts of the IEEE standards, DOE 
determined the standard is not sufficiently clear and detailed to adopt 
as the DOE test procedure. Therefore, the current DOE test procedure is 
a stand-alone test procedure based on the multiple industry standards.
    DOE seeks comment on the degree to which the DOE test procedure 
should consider and be harmonized further with the most recent relevant 
industry standards for distribution transformers, and whether any 
changes to the Federal test method would provide additional benefits to 
the public. DOE also requests comment on the benefits and burdens of 
adopting any industry/voluntary consensus-based or other appropriate 
test procedure, without modification.

[[Page 20723]]

3. Other Test Procedure Topics
    In addition to the issues identified earlier in this document, DOE 
welcomes comment on any other aspect of the existing test procedure for 
distribution transformers not already addressed by the specific areas 
identified in this document. DOE particularly seeks information that 
would improve the representativeness of the test procedure, as well as 
information that would help DOE create a procedure that would limit 
manufacturer test burden. Comments regarding repeatability and 
reproducibility are also welcome.
    DOE also requests information that would help DOE create procedures 
that would limit manufacturer test burden through streamlining or 
simplifying testing requirements. In particular, DOE notes that under 
Executive Order 13771, ``Reducing Regulation and Controlling Regulatory 
Costs,'' Executive Branch agencies such as DOE must manage the costs 
associated with the imposition of expenditures required to comply with 
Federal regulations. See 82 FR 9339 (Feb. 3, 2017). Consistent with 
that Executive Order, DOE encourages the public to provide input on 
measures DOE could take to lower the cost of its regulations applicable 
to distribution transformers consistent with the requirements of EPCA.

M. Compliance Date and Waivers

    EPCA prescribes that all representations of energy efficiency and 
energy use, including those made on marketing materials and product 
labels, must be made in accordance with an amended test procedure, 
beginning 180 days after publication of such a test procedure final 
rule in the Federal Register. (42 U.S.C. 6314(d)(1)) If DOE were to 
publish an amended test procedure, EPCA provides an allowance for 
individual manufacturers to petition DOE for an extension of the 180-
day period if the manufacturer may experience undue hardship in meeting 
the deadline. (42 U.S.C. 6314(d)(2)) To receive such an extension, 
petitions must be filed with DOE no later than 60 days before the end 
of the 180-day period and must detail how the manufacturer will 
experience undue hardship. Id.

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866

    The Office of Management and Budget (OMB) has determined that test 
procedure rulemakings do not constitute ``significant regulatory 
actions'' under section 3(f) of Executive Order 12866, Regulatory 
Planning and Review, 58 FR 51735 (Oct. 4, 1993). Accordingly, this 
action was not subject to review under the Executive Order by the 
Office of Information and Regulatory Affairs (OIRA) in the OMB.

B. Review Under Executive Orders 13771 and 13777

    On January 30, 2017, the President issued Executive Order 13771, 
``Reducing Regulation and Controlling Regulatory Costs.'' That Order 
stated the policy of the executive branch is to be prudent and 
financially responsible in the expenditure of funds, from both public 
and private sources. The Order stated it is essential to manage the 
costs associated with the governmental imposition of private 
expenditures required to comply with Federal regulations. This 
rulemaking is expected to be an E.O. 13771 other action because the 
costs of this action is zero.
    Additionally, on February 24, 2017, the President issued Executive 
Order 13777, ``Enforcing the Regulatory Reform Agenda.'' The Order 
required the head of each agency designate an agency official as its 
Regulatory Reform Officer (RRO). Each RRO oversees the implementation 
of regulatory reform initiatives and policies to ensure that agencies 
effectively carry out regulatory reforms, consistent with applicable 
law. Further, E.O. 13777 requires the establishment of a regulatory 
task force at each agency. The regulatory task force is required to 
make recommendations to the agency head regarding the repeal, 
replacement, or modification of existing regulations, consistent with 
applicable law. At a minimum, each regulatory reform task force must 
attempt to identify regulations that:
    (i) Eliminate jobs, or inhibit job creation;
    (ii) Are outdated, unnecessary, or ineffective;
    (iii) Impose costs that exceed benefits;
    (iv) Create a serious inconsistency or otherwise interfere with 
regulatory reform initiatives and policies;
    (v) Are inconsistent with the requirements of Information Quality 
Act, or the guidance issued pursuant to that Act, in particular those 
regulations that rely in whole or in part on data, information, or 
methods that are not publicly available or that are insufficiently 
transparent to meet the standard for reproducibility; or
    (vi) Derive from or implement Executive Orders or other 
Presidential directives that have been subsequently rescinded or 
substantially modified.
    DOE initially concludes that this rulemaking is consistent with the 
directives set forth in these executive orders. The proposed rule would 
not yield any costs or cost savings.

C. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires 
preparation of an initial regulatory flexibility analysis (IFRA) 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 DOE rulemaking process. 68 FR 7990. DOE has made 
its procedures and policies available on the Office of the General 
Counsel's website: http://energy.gov/gc/office-general-counsel.
    DOE reviewed the test procedures considered in this proposed rule 
to amend the test procedure for distribution transformers under the 
provisions of the Regulatory Flexibility Act and the procedures and 
policies published on February 19, 2003.
    The Small Business Administration (``SBA'') considers a business 
entity to be a small business, if, together with its affiliates, it 
employs less than a threshold number of workers specified in 13 CFR 
part 121. The size standards and codes are established by the 2017 
North American Industry Classification System (``NAICS'').
    Distribution transformers manufacturers are classified under NAICS 
code 335311, power, distribution, and specialty transformer 
manufacturing. The SBA sets a threshold of 750 employees or fewer for 
an entity to be considered as a small business.\22\ DOE conducted a 
focused inquiry into small business manufacturers of equipment covered 
by this rulemaking. DOE used its publicly available Compliance 
Certification Database \23\ to create a list of companies that import 
or otherwise manufacture distribution transformers covered by this 
rulemaking. Using these sources, DOE identified a total of 21 distinct 
manufacturers of distribution transformers.
---------------------------------------------------------------------------

    \22\ https://www.sba.gov/document/support--table-size-standards.
    \23\ https://www.regulations.doe.gov/certification-data.
---------------------------------------------------------------------------

    DOE then reviewed these data to determine whether the entities met 
the

[[Page 20724]]

SBA's definition of ``small business'' as it relates to NAICS code 
335311 and to screen out companies that do not offer equipment covered 
by this rulemaking, do not meet the definition of a ``small business,'' 
or are foreign owned and operated. Based on this review, DOE has 
identified 10 manufacturers that are potential small businesses. 
Through this analysis, DOE has determined the expected effects of the 
proposed rule on these covered small businesses and whether an IRFA was 
needed (i.e., whether DOE could certify that this rulemaking would not 
have a significant impact).
    The proposed requirements of this NOPR neither expand the scope of 
equipment currently subject to test procedures, nor do they place 
additional requirements on distribution transformers currently subject 
to test procedures. In addition, the proposed amendments would not 
alter the measured energy efficiency/energy use of the distribution 
transformers. Manufacturers would be able to rely on data generated 
under the current test procedure should the proposed amendments be 
finalized. Therefore, no proposed revisions would increase burden on 
manufacturers.
    However, in the NOPR, DOE is proposing to allow manufacturers to 
make voluntary representations of the performance of distribution 
transformers at conditions other than those required currently for 
compliance testing. DOE estimates that, if a manufacturer chose to make 
such representations, no additional testing cost would be incurred 
because the voluntary representations could be determined 
mathematically and without any additional testing required. Therefore, 
DOE concludes that no incremental testing cost and no additional 
testing burden would be incurred by manufacturers because of this 
proposed rule.
    Given that the proposed test procedures would not increase burden 
on small manufacturers, DOE certifies that the proposed testing 
procedure amendments would not have a ``significant economic impact on 
a substantial number of small entities,'' and the preparation of an 
IRFA is not warranted. DOE will submit a certification and supporting 
statement of factual basis to the Chief Counsel for Advocacy of the 
Small Business Administration for review under 5 U.S.C. 605(b).
    DOE seeks comment on whether the proposed test procedure changes 
would place new and significant burdens on a substantial number of 
small entities.

D. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of distribution transformers must certify to DOE that 
their products comply with any applicable energy conservation 
standards. To certify compliance, manufacturers must first obtain test 
data for their products according to the DOE test procedures, including 
any amendments adopted for those test procedures. DOE has established 
regulations for the certification and recordkeeping requirements for 
all covered consumer products and commercial equipment, including 
distribution transformers. (See generally 10 CFR part 429.) The 
collection-of-information requirement for the certification and 
recordkeeping is subject to review and approval by OMB under the 
Paperwork Reduction Act (PRA). This requirement has been approved by 
OMB under OMB control number 1910-1400. Public reporting burden for the 
certification is estimated to average 35 hours per response, including 
the time for reviewing instructions, searching existing data sources, 
gathering and maintaining the data needed, and completing and reviewing 
the collection of information.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

E. Review Under the Treasury and General Government Appropriations Act, 
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 proposed 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.

F. Review Under the National Environmental Policy Act of 1969

    In this proposed rule, DOE proposes test procedure amendments that 
it expects will be used to develop and implement future energy 
conservation standards for distribution transformers. 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 DOE's implementing 
regulations at 10 CFR part 1021. Specifically, this proposed rule would 
amend the existing test procedures without affecting the amount, 
quality or distribution of energy usage, and, therefore, would not 
result in any environmental impacts. Thus, this rulemaking is covered 
by Categorical Exclusion A5 under 10 CFR part 1021, subpart D, which 
applies to any rulemaking that interprets or amends an existing rule 
without changing the environmental effect of that rule. Accordingly, 
neither an environmental assessment nor an environmental impact 
statement is required.

G. 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 examine the 
constitutional and statutory authority supporting any action that would 
limit the policymaking discretion of the States and to 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 this proposed rule and has 
determined that it would 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. EPCA governs and prescribes Federal 
preemption of State regulations as to energy conservation for the 
products that are the subject of this proposed rule. States can 
petition DOE for exemption from such preemption to the extent, and 
based on criteria, set forth in EPCA. (42 U.S.C. 6297(d)) No further 
action is required by Executive Order 13132.

H. Review Under Executive Order 12988

    Regarding the review of existing regulations and the promulgation 
of new regulations, section 3(a) of Executive Order 12988, ``Civil 
Justice Reform,'' 61 FR 4729 (Feb. 7, 1996), imposes on Federal 
agencies the general duty to adhere to the following

[[Page 20725]]

requirements: (1) Eliminate drafting errors and ambiguity, (2) write 
regulations to minimize litigation, (3) provide a clear legal standard 
for affected conduct rather than a general standard, and (4) 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 sections 3(a) and 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, the proposed rule meets the relevant standards of Executive Order 
12988.

I. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) 
requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments and the 
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531). 
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://energy.gov/gc/office-general-counsel. DOE examined this 
proposed rule according to UMRA and its statement of policy and 
determined that the rule contains neither an intergovernmental mandate, 
nor a mandate that may result in the expenditure of $100 million or 
more in any year, so these requirements do not apply.

J. Review Under Executive Order 12630

    DOE 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 that might require compensation under the Fifth 
Amendment to the U.S. Constitution.

K. Review Under 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 (Feb. 22, 2002), and 
DOE's guidelines were published at 67 FR 62446 (Oct. 7, 2002). DOE has 
reviewed this proposed rule under the OMB and DOE guidelines and has 
concluded that it is consistent with applicable policies in those 
guidelines.

L. 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 OMB, 
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.
    The proposed regulatory action to amend the test procedure for 
measuring the energy efficiency of distribution transformers is not a 
significant regulatory action under Executive Order 12866. Moreover, it 
would not have a significant adverse effect on the supply, 
distribution, or use of energy, nor has it been designated as a 
significant energy action by the Administrator of OIRA. Therefore, it 
is not a significant energy action, and, accordingly, DOE has not 
prepared a Statement of Energy Effects.

M. 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; 42 U.S.C. 7101), DOE must comply with section 32 of the 
Federal Energy Administration Act of 1974, as amended by the Federal 
Energy Administration Authorization Act of 1977. (15 U.S.C. 788; FEAA) 
Section 32 essentially provides in relevant part that, where a proposed 
rule authorizes or requires use of commercial standards, the notice of 
proposed rulemaking must inform the public of the use and background of 
such standards. In addition, section 32(c) requires DOE to consult with 
the Attorney General and the Chairman of the Federal Trade Commission 
(FTC) concerning the impact of the commercial or industry standards on 
competition.
    The proposed modifications to the test procedure for distribution 
transformers in this NOPR do not incorporate by reference any 
commercial testing standards. Therefore, the requirements of section 
32(b) of the FEAA do not apply.

N. Referenced Consensus Standards

    In this NOPR, DOE does not propose to incorporate by reference any 
industry test standards. Rather, DOE proposes that the test procedure 
continue to be stand-alone, and be based on NEMA TP 2-1998 and NEMA TP 
2-2005, and the latest versions of the IEEE standards, IEEE C57.12.90-
2015, IEEE C57.12.91-2011, IEEE C57.12.00-2015, and IEEE C57.12.01-
2015.

V. Public Participation

A. Submission of Comments

    DOE will accept comments, data, and information regarding this 
proposed rule no later than the date provided in the DATES section at 
the beginning of this proposed rule. Interested parties may submit 
comments using any of the methods described in the ADDRESSES section at 
the beginning of this notice.

[[Page 20726]]

    Submitting comments via http://www.regulations.gov. The http://www.regulations.gov web page will require you to provide your name and 
contact information. Your contact information will be viewable to DOE 
Building Technologies staff only. Your contact information will not be 
publicly viewable except for your first and last names, organization 
name (if any), and submitter representative name (if any). If your 
comment is not processed properly because of technical difficulties, 
DOE will use this information to contact you. If DOE cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, DOE may not be able to consider your comment.
    However, your contact information will be publicly viewable if you 
include it in the comment itself or in any documents attached to your 
comment. Any information that you do not want to be publicly viewable 
should not be included in your comment, nor in any document attached to 
your comment. Otherwise, persons viewing comments will see only first 
and last names, organization names, correspondence containing comments, 
and any documents submitted with the comments.
    Do not submit to http://www.regulations.gov information for which 
disclosure is restricted by statute, such as trade secrets and 
commercial or financial information (hereinafter referred to as 
Confidential Business Information (CBI)). Comments submitted through 
http://www.regulations.gov cannot be claimed as CBI. Comments received 
through the website will waive any CBI claims for the information 
submitted. For information on submitting CBI, see the Confidential 
Business Information section.
    DOE processes submissions made through http://www.regulations.gov 
before posting. Normally, comments will be posted within a few days of 
being submitted. However, if large volumes of comments are being 
processed simultaneously, your comment may not be viewable for up to 
several weeks. Please keep the comment tracking number that http://www.regulations.gov provides after you have successfully uploaded your 
comment.
    Submitting comments via email, hand delivery/courier, or mail. 
Comments and documents submitted via email, hand delivery/courier, or 
mail also will be posted to http://www.regulations.gov. If you do not 
want your personal contact information to be publicly viewable, do not 
include it in your comment or any accompanying documents. Instead, 
provide your contact information in a cover letter. Include your first 
and last names, email address, telephone number, and optional mailing 
address. The cover letter will not be publicly viewable as long as it 
does not include any comments.
    Include contact information each time you submit comments, data, 
documents, and other information to DOE. If you submit via mail or hand 
delivery/courier, please provide all items on a CD, if feasible, in 
which case it is not necessary to submit printed copies. No 
telefacsimiles (faxes) will be accepted.
    Comments, data, and other information submitted to DOE 
electronically should be provided in PDF (preferred), Microsoft Word or 
Excel, WordPerfect, or text (ASCII) file format. Provide documents that 
are not secured, that are written in English, and that are free of any 
defects or viruses. Documents should not contain special characters or 
any form of encryption and, if possible, they should carry the 
electronic signature of the author.
    Campaign form letters. Please submit campaign form letters by the 
originating organization in batches of between 50 to 500 form letters 
per PDF or as one form letter with a list of supporters' names compiled 
into one or more PDFs. This reduces comment processing and posting 
time.
    Confidential Business Information. Pursuant to 10 CFR 1004.11, any 
person submitting information that he or she believes to be 
confidential and exempt by law from public disclosure should submit via 
email, postal mail, or hand delivery/courier two well-marked copies: 
One copy of the document marked ``confidential'' including all the 
information believed to be confidential, and one copy of the document 
marked ``non-confidential'' with the information believed to be 
confidential deleted. Submit these documents via email or on a CD, if 
feasible. DOE will make its own determination about the confidential 
status of the information and treat it according to its determination.
    Factors of interest to DOE when evaluating requests to treat 
submitted information as confidential include (1) a description of the 
items, (2) whether and why such items are customarily treated as 
confidential within the industry, (3) whether the information is 
generally known by or available from other sources, (4) whether the 
information has previously been made available to others without 
obligation concerning its confidentiality, (5) an explanation of the 
competitive injury to the submitting person that would result from 
public disclosure, (6) when such information might lose its 
confidential character due to the passage of time, and (7) why 
disclosure of the information would be contrary to the public interest.
    It is DOE's policy that all comments may be included in the public 
docket, without change and as received, including any personal 
information provided in the comments (except information deemed to be 
exempt from public disclosure).
    DOE considers public participation to be a very important part of 
the process for developing test procedures and energy conservation 
standards. DOE actively encourages the participation and interaction of 
the public during the comment period in each stage of this process. 
Interactions with and between members of the public provide a balanced 
discussion of the issues and assist DOE in the process. Anyone who 
wishes to be added to the DOE mailing list to receive future notices 
and information about this process should contact Appliance and 
Equipment Standards Program staff at (202) 586-6636 or via email at 
[email protected].

B. Issues on Which DOE Seeks Comment

    Although DOE welcomes comments on any aspect of this proposal, DOE 
is particularly interested in receiving comments and views of 
interested parties concerning the following issues:
    (1.) DOE requests comment on: (1) Whether the current definition of 
rectifier transformer is sufficiently specific, (2) if not, what 
modifications would make it sufficiently specific, and (3) whether 
partial output phase shift, harmonic current tolerance, or other 
electrical properties may be used to reliably identify rectifier 
transformers.
    (2.) DOE requests comment on: (1) Whether the current definition of 
drive transformer is sufficiently specific, (2) if not, what 
modifications would make it sufficiently specific, and (3) the level of 
technical similarity drive transformers bear to rectifier transformers.
    (3.) DOE requests comment on its proposed definition of ``per-unit 
load'' and its proposal to consolidate the usage of various terms 
referring to less-than-full rated load to the single term ``per-unit 
load.''
    (4.) DOE requests comment on its proposed definition of 
``terminal.''
    (5.) DOE requests comment on its proposed definition of ``auxiliary 
device,'' and whether certain components should be added or removed 
from the listed auxiliary devices and why. DOE also requests comment on 
whether it is appropriate to include functional component

[[Page 20727]]

designations as part of a definition of ``auxiliary device'' and, if 
so, which functions and why.
    (6.) DOE requests comment on its proposed updated definition of 
``low-voltage dry-type distribution transformer.''
    (7.) DOE requests comment on its proposed updated definition of 
``reference temperature.''
    (8.) DOE requests comment on the proposed updates based on the 
latest version of the applicable IEEE standards for testing 
distribution transformers, and specifically regarding whether industry 
is already testing to the requirements of those IEEE standards.
    (9.) DOE requests comment on the tentative determination that each 
of the proposals do not increase test cost or burden, and that they 
would not result in different measured values than the current test 
procedure.
    (10.) DOE requests comment on the proposal to amend the DOE test 
procedure to permit manufacturers to make voluntary representations at 
any additional PUL and/or reference temperature, and whether this would 
assist consumers in making better purchasing decisions based on their 
specific installation conditions. DOE requests comment on whether the 
current DOE test procedure would be appropriate at non-mandatory PULs 
and reference temperatures.
    (11.) DOE requests comment on secondary winding configurations. DOE 
also requests comment on the magnitude of the additional losses 
associated with the less efficient configurations as well as the 
relative period of operation in each winding configuration.
    (12.) DOE requests comments regarding when, or at what number of 
time constants, stability is reached for the voltmeter-ammeter method 
and the resistance bridge method.
    (13.) DOE seeks comment on its proposal to maintain the laboratory 
ambient and transformer internal temperature requirements with no 
changes.
    (14.) DOE seeks comment on its proposal to modify section 4.1 of 
appendix A to read ``. . .Test all distribution transformers using a 
sinusoidal waveform (k=1).''
    (15.) DOE requests comment on its understanding of the impact and 
associated costs of the proposed test procedure. To the extent 
commenters believe that manufacturers would not be able to rely on data 
generated under the current test procedure should the proposed 
amendments be finalized, DOE requests comment on the potential 
associated costs.
    (16.) DOE seeks comment on the degree to which the DOE test 
procedure should consider and be harmonized further with the most 
recent relevant industry standards for distribution transformers, and 
whether any changes to the Federal test method would provide additional 
benefits to the public. DOE also requests comment on the benefits and 
burdens of adopting any industry/voluntary consensus-based or other 
appropriate test procedure, without modification.
    (17.) DOE seeks comment on whether the proposed test procedure 
changes would place new and significant burdens on a substantial number 
of small entities.

VI. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this proposed 
rule.

List of Subjects in 10 CFR Part 431

    Administrative practice and procedure, Confidential business 
information, Energy conservation test procedures, Incorporation by 
reference, and Reporting and recordkeeping requirements.

    Signed in Washington, DC, on April 23, 2019.
Steven Chalk,
Acting Deputy Assistant Secretary for Energy Efficiency, Energy 
Efficiency and Renewable Energy.

    For the reasons stated in the preamble, DOE is proposing to amend 
part 431 of Chapter II of Title 10, Code of Federal Regulations 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; 28 U.S.C. 2461 note.

0
2. Section 431.192 is amended by revising the definitions of Low-
voltage dry-type distribution transformer and Reference temperature, 
and adding in alphabetical order, definitions for Auxiliary device, 
Per-unit load, and Terminal, to read as follows:


Sec.  431.192   Definitions.

* * * * *
    Auxiliary device means a localized component of a distribution 
transformer that is a circuit breaker, switch, fuse, or surge/lightning 
arrester.
* * * * *
    Low-voltage dry-type distribution transformer means a distribution 
transformer that--
    (1) Has an input voltage of 600 volts or less;
    (2) Is air-cooled; and
    (3) Does not use insulating liquid as a coolant.
* * * * *
    Per-unit load means the fraction of rated load.
* * * * *
    Reference temperature means the temperature at which the 
transformer losses are determined, and to which such losses are 
corrected if testing is done at a different point. (Reference 
temperature values are specified in the test method in appendix A to 
this subpart.)
* * * * *
    Terminal means a conducting element of a distribution transformer 
providing electrical connection to an external conductor that is not 
part of the transformer.
* * * * *
0
3. Section 431.193 is revised to read as follows:


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. The test procedures specified in appendix A 
to this subpart apply only to distribution transformers subject to 
energy conservation standards at Sec.  431.196.
0
4. Section 431.196 is amended by revising the Notes in paragraphs 
(a)(1), (a)(2), (b)(1), (b)(2), (c)(1), and (c)(2), to read as follows:


Sec.  431.196   Energy conservation standards and their effective 
dates.

    (a) * * *
    (1) * * *

    Note: All efficiency values are at 35 percent per-unit load.

    (2) * * *

    Note: All efficiency values are at 35 percent per-unit load.

    (b) * * *
    (1) * * *

    Note: All efficiency values are at 50 percent per-unit load.

    (2) * * *

    Note: All efficiency values are at 50 percent per-unit load.

    (c) * * *
    (1) * * *

    Note: All efficiency values are at 50 percent per-unit load.


[[Page 20728]]


    (2) * * *

    Note:  All efficiency values are at 50 percent per-unit load.

* * * * *
0
5. Appendix A to subpart K of part 431 is amended by:
0
a. Revising section 2.0;
0
 b. Adding sections 2.1, 2.2, and 2.3;
0
 c. Revising paragraph (b) and adding paragraph (c) in section 3.1;
0
 d. Revising section 3.2.1.1;
0
 e. Revising paragraph (b) of section 3.2.1.2;
0
 f. Revising section 3.2.2;
0
 g. Revising section 3.3;
0
 h. Revising paragraphs (a) introductory text and paragraph (b) in 
section 3.3.2;
0
 i. Revising section 3.3.3;
0
 j. Revising the introductory text and adding paragraphs (f), (g), (h), 
and (i) in section 3.4.1;
0
 k. Revising paragraph (a) in section 3.4.2;
0
 l. Revising paragraph (a) in section 3.5;
0
 m. Revising section 4.1;
0
 n. Revising paragraph (a) and adding paragraph (c) in section 4.3;
0
 o. Revising paragraph (b) and the note following the paragraph in 
section 4.4.2;
0
 p. Revising section 4.4.3.3;
0
 q. Revising section 5.1;
0
 r. Revising section 6.0;
0
 s. Revising section 6.1;
0
 t. Revising paragraph (a) of section 6.2; and
0
 u. Adding section 7.0.
    The additions and revisions read as follows:

Appendix A to Subpart K of Part 431--Uniform Test Method for Measuring 
the Energy Consumption of Distribution Transformers

* * * * *

2.0 Per-Unit Load, Reference Temperature, and Accuracy Requirements

2.1 Per-unit Load

    In conducting the test procedure in this Appendix for the 
purpose of:
    (a) Certification to an energy conservation standard, the 
applicable per-unit load in Table 2.1 must be used; or
    (b) Making voluntary representations as provided in section 7.0 
at an additional per-unit load, select the per-unit load of 
interest.

    Table 2.1--Per-Unit Load for Certification to Energy Conservation
                                Standards
------------------------------------------------------------------------
                                                               Per-unit
              Distribution transformer category                  load
                                                               (percent)
------------------------------------------------------------------------
Liquid-immersed.............................................          50
Medium-voltage dry-type.....................................          50
Low-voltage dry-type........................................          35
------------------------------------------------------------------------

2.2 Reference Temperature

    In conducting the test procedure in this Appendix for the 
purpose of:
    (a) Certification to an energy conservation standard, the 
applicable reference temperature in Table 2.2 must be used; or
    (b) Making voluntary representations as provided in section 7.0 
at an additional reference temperature, select the reference 
temperature of interest.

      Table 2.2--Reference Temperature for Certification to Energy
                         Conservation Standards
------------------------------------------------------------------------
     Distribution transformer category          Reference temperature
------------------------------------------------------------------------
Liquid-immersed...........................  20 [deg]C for no-load loss.
                                            55 [deg]C for load loss.
Medium-voltage dry-type...................  20 [deg]C for no-load loss.
                                            75 [deg]C for load loss.
Low-voltage dry-type......................  20 [deg]C for no-load loss.
                                            75 [deg]C for load loss.
------------------------------------------------------------------------

2.3 Accuracy Requirements

    (a) Equipment and methods for loss measurement must be 
sufficiently accurate that measurement error will be limited to the 
values shown in Table 2.3.

 Table 2.3--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..........................  1.5 [deg]C for liquid-
                                        immersed distribution
                                        transformers, and 2.0 [deg]C for low-voltage
                                        dry-type and medium-voltage dry-
                                        type distribution transformers.
------------------------------------------------------------------------

    (b) Only instrument transformers meeting the 0.3 metering 
accuracy class, or better, may be used under this test method.

3.0 * * *

3.1 General Considerations

* * * * *
    (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 while taking measurements, 
such as those in section 3.4, in order to maintain measurement 
uncertainty limits specified in Table 2.3.
    (c) Measure resistance with the transformer energized by a 60 Hz 
supply.
* * * * *

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 insulating liquid 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 insulating liquid, with one located directly above 
the winding and other located directly below the winding.

3.2.1.2 Conditions

* * * * *
    (b) The temperature of the insulating liquid has stabilized, and 
the difference between the top and bottom temperature does not 
exceed 5 [deg]C. The temperature of the insulating liquid is 
considered stable if the top liquid temperature does not vary more 
than 2 [deg]C in a 1-h period.

3.2.2 Dry-Type Distribution Transformers

    Record the winding temperature (Tdc) of dry-type 
transformers as one 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; or
    (b) 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
    (c) For ventilated units or sealed units, use the ambient 
temperature of the test area, only if the following conditions are 
met:
    (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.
    Enclosure surface temperatures for sealed units must not differ 
from the test area ambient temperature by more than 2 [deg]C.
    (2) Test area ambient temperature must not have changed by more 
than 3 [deg]C for 3 hours before the test.
    (3) 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 (i.e., after 48 hours, the transformer windings can be 
assumed to have stabilized at the level of the ambient temperature. 
Any stabilization time beyond 48 hours is optional).

[[Page 20729]]

3.3 Resistance Measurement Methods

    Make resistance measurements using either the resistance bridge 
method (section 3.3.1), the voltmeter-ammeter method (section 3.3.2) 
or resistance meters (section 3.3.3). In each instance when this 
Appendix 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.
* * * * *

3.3.2 Voltmeter-Ammeter Method

    (a) Employ the voltmeter-ammeter method only if 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. * 
* *
    (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 a minimum of four readings of voltage and current. 
Voltage and current readings must be taken simultaneously for each 
of the readings. Calculate the average voltage and average current 
using the readings. Determine the winding resistance Rdc 
by using equation 3-4 as follows:
[GRAPHIC] [TIFF OMITTED] TP10MY19.000

Where:

Vmdc is the average voltage measured by the voltmeter V, 
and
Imdc is the average current measured by the ammeter (A).
* * * * *

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 2.3 in section 
2.3.
* * * * *

3.4.1 Required Actions

    The following requirements must be observed when making 
resistance measurements:
* * * * *
    (f) Keep the polarity of the core magnetization constant during 
all resistance measurements.
    (g) For single-phase windings, measure the resistance from 
terminal to terminal. The total winding resistance is the terminal-
to-terminal measurement. For series-parallel windings, the total 
winding resistance is the sum of the series terminal-to-terminal 
section measurements.
    (h) For wye windings, measure the resistance from terminal to 
terminal or from terminal to neutral. For the total winding 
resistance, the resistance of the lead from the neutral connection 
to the neutral bushing may be excluded. For terminal-to-terminal 
measurements, the total resistance reported is the sum of the three 
measurements divided by two.
    (i) For delta windings, measure resistance from terminal to 
terminal with the delta closed or from terminal to terminal with the 
delta open to obtain the individual phase readings. The total 
winding resistance is the sum of the three-phase readings if the 
delta is open. If the delta is closed, the total winding resistance 
is the sum of the three phase-to-phase readings times 1.5.

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 2.3:
* * * * *

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.
* * * * *

4.0 * * *

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 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 all distribution transformers using a 
sinusoidal waveform (k=1). Measure losses with the transformer 
energized by a 60 Hz supply.
* * * * *

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 2.3 in 
section 2.3. 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 2.3 or the individual phase angle error exceeds the 
values specified in section 4.5.3.
* * * * *
    (c) Both load loss and no-load loss measurements must be made 
from terminal to terminal.
* * * * *

4.4.2 No-Load Loss Test

* * * * *
    (b) Adjust the voltage to the specified value as indicated by 
the average-sensing voltmeter. Automatically and simultaneously 
record the values of rms voltage, rms current, electrical power, and 
average voltage using a digital data acquisition system. 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.

* * * * *

4.4.3.3 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. For both 
certification to energy conservation standards and voluntary 
representations, 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. For 
certification to energy conservation standards only, if the no-load 
loss measurements were made between 10 [deg]C and 30 [deg]C, this 
correction is not required. Correct the no-load loss to the 
reference temperature by using equation 4-2 as follows:
[GRAPHIC] [TIFF OMITTED] TP10MY19.001

Where:

Pnc is the no-load losses corrected for waveform distortion and then 
to the reference temperature,
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.
* * * * *

[[Page 20730]]

5.0 * * *

5.1 Output Loading Level Adjustment

    If the per-unit load selected in section 2.1 is different from 
the per-unit load 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] TP10MY19.002

Where:

Plc is the adjusted load loss power to the per-unit load,
Plc2 is as calculated in section 4.5.3.3,
Por is the rated transformer apparent power (name plate),
Pos is the adjusted rated transformer apparent power, where Pos = 
PorL, and
L is the per-unit load, e.g., if the per-unit load is 50 percent 
then ``L'' is 0.5.
* * * * *

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 2.3, Table 2.3.

6.1 Test Equipment

    The party performing the tests must 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 must 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

* * * * *
    (a) Identify the measurements to be made, the accuracy required 
(section 2.3) and select the appropriate measurement and test 
equipment;
* * * * *

7.0 Test Procedure for Voluntary Representations

    Follow sections 1.0 through 6.0 of this appendix using the per-
unit load and/or reference temperature of interest for voluntary 
representations of efficiency, and corresponding values of load loss 
and no-load loss at additional per-unit load and/or reference 
temperature. Representations made at a per-unit load and/or 
reference temperature other than those required to comply with the 
energy conservation standards at Sec.  431.196 must be in addition 
to, and not in place of, a representation at the required DOE 
settings for per-unit load and reference temperature. As a best 
practice, the additional settings of per-unit load and reference 
temperature should be provided with the voluntary representations.

[FR Doc. 2019-09218 Filed 5-9-19; 8:45 am]
BILLING CODE 6450-01-P