low voltage distribution transformers - weat · 2015. 8. 19. · 12 distribution transformer means...

8 8

Your Presenters

> Thomas Patzner

Product Manager, Low Voltage Transformers

> Marquette University – Electrical Engineering

> Apprentice Electrician

> Low Voltage Transformers

- Co-op (Square D Company) (lab testing, inoperative trouble shooting, designing of units)

- Application Engineer (Square D Company)

- Sales Engineer (Jefferson Transformer)

- Marketing (Square D Company)

- Product Manager (Square D Company)

9

The Energy Policy and Conservation Act of 1975 (EPCA), as amended, prescribes

energy conservation standards for various consumer products and certain commercial

and industrial equipment, including distribution transformers.

10

EPACT 1992

• Authorized Department of Energy to evaluate

Distribution Transformers

Market Response

• Energy Star – added Distribution Transformers to

program – 1994

• NEMA – publishes Standard for Higher Efficient

Transformers - 1996

• States Mandated NEMA Standard Level for Low

Voltage Products (1999 through 2005)

Department of Energy

• DOE start analysis process

• Advance Notice of Public Ruling – July, 2004

11

EPACT 2005

• Authorized DOE to mandate efficiency levels on

Distribution Transformers

• Low Voltage Transformers – Mandated to TP1 standard

effected Jan, 2007

Market Response

• Energy Star Program discontinued May, 2007

Department of Energy

• DOE stop all work being done on Low Voltage units from

the EPACT1992

• DOE finalized Medium Voltage

Final Rule – 2007 – mandating levels effected Jan, 2010

• 10 CFR 431 includes how to test the distribution

transformers

• 10 CFR 429 -CERTIFICATION, COMPLIANCE, AND

ENFORCEMENT… COMMERCIAL AND INDUSTRIAL EQUIPMENT

12

Distribution transformer means a transformer that—

(1) Has an input voltage of 34.5 kV or less;

(2) Has an output voltage of 600 V or less;

(3) Is rated for operation at a frequency of 60 Hz; and

(4) Has a capacity of 10 kVA to 2500 kVA for liquid-immersed units and 15 kVA

to 2500 kVA for dry-type units; but…

Liquid-immersed distribution transformer means a distribution

transformer in which the core and coil assembly is immersed in an

insulating liquid.

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.

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 oil as a coolant.

13

Distribution transformer means a transformer that—

(5) The term “distribution transformer” does not include a transformer that is

an—

(i) Autotransformer;

(ii) Drive (isolation) transformer;

(iii) Grounding transformer;

(iv) Machine-tool (control) transformer;

(v) Nonventilated transformer;

(vi) Rectifier transformer;

(vii) Regulating transformer;

(viii) Sealed transformer;

(ix) Special-impedance transformer;

(x) Testing transformer;

(xi) Transformer with tap range of 20 percent or more;

(xii) Uninterruptible power supply transformer; or

(xiii) Welding transformer.

14

Distribution

Transformer

Liquid-immersed Dry-Type

Low Voltage Medium Voltage

(2007 Final Rule)

(2007 Final Rule) EPACT 2005

Final Rule – April 2013

http://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/66

http://www.regulations.gov/

15

The ERAC subcommittee for medium voltage liquid-immersed,

and dry-type distribution transformers consisted of

representatives of parties, listed below, having a defined stake

in the outcome of the proposed standards and included:

The ERAC subcommittee for low voltage distribution transformers

consisted of representatives of parties having a defined stake in the

outcome of the proposed standards and included:

> ABB Inc.

> AK Steel Corporation

> American Council for an Energy-Efficient Economy

> American Public Power Association

> Appliance Standards Awareness Project

> ATI-Allegheny Ludlum

> Baltimore Gas and Electric

> Cooper Power Systems

> Earthjustice

> Edison Electric Institute

> Fayetteville Public Works Commission

> Federal Pacific Company

> Howard Industries Inc.

> LakeView Metals

> Efficiency and Renewables Advisory Committee member

> Metglas, Inc.

> National Electrical Manufacturers Association

> National Resources Defense Council

> National Rural Electric Cooperative Association

> Northwest Power and Conservation Council

> Pacific Gas and Electric Company

> Progress Energy

> Prolec-GE

> U.S. Department of Energy

> AK Steel Corporation

> American Council for an Energy-Efficient Economy

> Appliance Standards Awareness Project

> ATI-Allegheny Ludlum

> EarthJustice

> Eaton Corporation

> Federal Pacific Company

> Lakeview Metals

> Efficiency and Renewables Advisory Committee member

> Metglas, Inc.

> National Electrical Manufacturers Association

> Natural Resources Defense Council

> ONYX Power

> Pacific Gas and Electric Company

> Schneider Electric

> U.S. Department of Energy

16

10 CFR 431 – April 2013 Final Rule

Conclusion

Based on the analyses culminating in this final rule, DOE

found the benefits to the nation of the standards

(energy savings, consumer LCC savings, positive NPV

of customer benefit, and emission reductions) outweigh

the burdens (loss of INPV and LCC increases for some

users of this equipment).

DOE has concluded that the standards in today's final

rule represent the maximum improvement in energy

efficiency that is technologically feasible and

economically justified, and would result in significant

conservation of energy.

17


A diversity of core materials are cost

competitive and economically feasible for all

Design Lines.

EL 1 for all design lines

Maximum efficiency achievable with M3 Steel

Maximum NPV with 7% discounting


Maximum source energy savings with

positive NPV (7% discounting)

Maximum technologically feasible (max tech)

TSL 1

TSL 2

TSL 3

TSL 4

TSL 5

TSL 6

TSL 7

Liquid-immersed Distribution transformers:

18


A diversity of core materials are cost


Design Lines. TSL 1

Liquid-immersed Distribution transformers:

Type Design linePhase

countTSL Energy efficiency level Efficiency(%)

Liquid-immersed 1 1 1 1 (0.4 actual)* 99.11

2 1 Base (0.5 actual)* 98.95

3 1 1 (1.1 actual)* 99.49

4 3 1 99.16

5 3 1 99.48

19


Maximum efficiency achievable with M6 Steel

NEMA Premium Levels (CSL3-2004)

Maximum efficiency achievable using butt lap

core mitering for single-phase designs and

full mitering for three-phase designs





TSL 1

TSL 2

TSL 3

TSL 4

TSL 5

TSL 6

Low Voltage Distribution transformers:

20


NEMA Premium Levels (CSL3-2004) TSL 2

Low Voltage Distribution transformers:



Low-voltage dry-type 6 1 2 Base 98.00

7 3 3 98.60

8 3 2 99.02

21



A diversity of core materials are cost-


design lines





TSL 1

TSL 2

TSL 3

TSL 4

TSL 5

Medium Voltage Dry Type Distribution transformers:

22


A diversity of core materials are cost-


design lines TSL 2

Medium Voltage Dry Type Distribution transformers:



Medium-voltage dry-type 9 3 2 1 98.93

10 3 2 99.37

11 3 1 98.81

12 3 2 99.30

13A 3 1 98.69

13B 3 2 99.28

23

431.196 Energy conservation

standards and their effective

dates.

(a) Low Voltage Dry-Type Distribution Transformers

kVA

Efficiency

(%) kVA

Efficiency

(%) kVA

Efficiency

(%) kVA

Efficiency

(%)

15 97.7 15 97.0 15 97.70 15 97.89

25 98.0 30 97.5 25 98.00 30 98.23

37.5 98.2 45 97.7 37.5 98.20 45 98.40

50 98.3 75 98.0 50 98.30 75 98.60

75 98.5 112.5 98.2 75 98.50 112.5 98.74

100 98.6 150 98.3 100 98.60 150 98.83

167 98.7 225 98.5 167 98.70 225 98.94

250 98.8 300 98.6 250 98.80 300 99.02

333 98.9 500 98.7 333 98.90 500 99.14

750 98.8 750 99.23

1000 98.9 1000 99.28

(1) The efficiency of a low-

voltage, dry-type distribution

transformer manufactured on or

after January 1, 2007, but before

January 1, 2016

(2) The efficiency of a low-

voltage dry-type distribution


after January 1, 2016,

Single-phase Three-phase Single-phase Three-phase

Low Voltage Distribution Transformers

Three Phase set at EL3 and EL2 (NEMA

PREMIUM, CSL3-2004) levels from the

DOE engineering analysis

Single Phase set at Base levels (no

change) from the DOE engineering

analysis

Minimum Levels of Efficiency at four

significant digits from three (ie - .xxx to .xxxx)

Note

EL = Efficiency Level

CSL=Candidate Standard Level

24



dates.

(b) Liquid-Immersed Distribution Transformers.

kVA

Efficiency

(%)

kVA

Efficiency

(%)

kVA

Efficiency

(%)

kVA

Efficiency

(%)

10 98.62 15 98.36 10 98.70 15 98.65

15 98.76 30 98.62 15 98.82 30 98.83

25 98.91 45 98.76 25 98.95 45 98.92

37.5 99.01 75 98.91 37.5 99.05 75 99.03

50 99.08 112.5 99.01 50 99.11 112.5 99.11

75 99.17 150 99.08 75 99.19 150 99.16

100 99.23 225 99.17 100 99.25 225 99.23

167 99.25 300 99.23 167 99.33 300 99.27

250 99.32 500 99.25 250 99.39 500 99.35

333 99.36 750 99.32 333 99.43 750 99.40

500 99.42 1000 99.36 500 99.49 1000 99.43

667 99.46 1500 99.42 667 99.52 1500 99.48

833 99.49 2000 99.46 833 99.55 2000 99.51

2500 99.49 2500 99.53

(2) The efficiency of a liquid-

immersed distribution


after January 1, 2016

Single-phase Three-phaseSingle-phase Three-phase

(1) The efficiency of a liquid-

immersed distribution



January 1, 2016,Liquid-immersed Distribution Transformers

EL1 (or lower) levels from the DOE

engineering analysis Note EL = Efficiency Level

25



dates.

(c) Medium-Voltage Dry-Type Distribution Transformers.

20-45 kV 46-95 kV ≥96 kV 20-45 kV 46-95 kV ≥96 kV

Efficiency

(%)

Efficiency

(%)

Efficiency

(%)

Efficiency

(%)

Efficiency

(%)

Efficiency

(%)

15 98.10 97.86 15 98.10 97.86

25 98.33 98.12 25 98.33 98.12

37.5 98.49 98.3 37.5 98.49 98.30

50 98.60 98.42 50 98.60 98.42

75 98.73 98.57 98.53 75 98.73 98.57 98.53

100 98.82 98.67 98.63 100 98.82 98.67 98.63

167 98.96 98.83 98.8 167 98.96 98.83 98.80

250 99.07 98.95 98.91 250 99.07 98.95 98.91

333 99.14 99.03 98.99 333 99.14 99.03 98.99

500 99.22 99.12 99.09 500 99.22 99.12 99.09

667 99.27 99.18 99.15 667 99.27 99.18 99.15

833 99.31 99.23 99.20 833 99.31 99.23 99.20

kVA

(1) The efficiency of a medium-




January 1, 2016,

(2) The efficiency of a medium-



after January 1, 2016,

BIL*

kVA

BIL*

Single-phaseSingle-phase

26



dates.

Medium-Voltage Distribution Transformers

Three Phase set at EL1 and EL2 levels

from the DOE engineering analysis

Negotiate Levels with all stack holders Note EL = Efficiency Level

27 27

Form / Fit / Function

Low Voltage Distribution Transformers

DL7 (75kVA)

DL8 (300kVA)

Liquid-immersed Distribution Transformers

DL5 (1500kVA)

Medium Voltage Dry-Type Distribution

Transformers

DL12 (1500kVA)

Comparing actual existing designs to new product

offering available in 2016.

These are Schneider Electric comparison, other

manufactures might have different changes

28

Design Line 7, 75kVA, Aluminum, 150°C / 220 Ins

F

O

R

M

Top Ventilation front only,

Primary / Secondary Terminals separated, (meet all NEC bending requirements side and bottom entry)

Mounting Bracket

Square D: EE75T3H Square D: EX75T3H

F

I

T

H – 37”

W – 30”

D – 20”

Weight - 585 pounds

H – 42”

W – 30.63”

D – 22.75”

Weight - 710 pounds

F

U

N

C

T

I

O

N

98.0% Efficient @ 35% Loading 75°C

IZ – 3.7% 5.6k 10kAIC

Inrush – 10X Rated

Core Loss: 253 Watts

Coil Loss: 2518 Watts

BTU’s @ 75% Load: 5695

Sound Level: 50dB


IZ – 5.88% 3.5k 10kAIC

Inrush – 5.7X Rated



BTU’s @ 75% Load: 4695

Sound Level: 47dB

29

Design Line 8, 300kVA, Aluminum, 150°C / 220 Ins

F

O

R

M

Ventilation front only,

Open Bottom increase access

Primary / Secondary Terminals separated, (meet all NEC bending requirements side and bottom entry)

Mounting Bracket

Square D: EE300T3H Square D: EX300T3H

F

I

T

H – 49.5”

W – 41”

D – 32”

Weight – 1350 pounds

H – 57.5”

W – 40.1”

D – 32.75”

Weight - 1975 pounds

F

U

N

C

T

I

O

N


IZ – 5.9% 14.1k 18kAIC / 22kAIC




BTU’s @ 75% Load: 15472

Sound Level: 55dB


IZ – 4.95% 16.8k 18kAIC / 22kAIC




BTU’s @ 75% Load: 10605

Sound Level: 52dB

30

Design Line 5, 1500 KVA, Aluminum, 65C Rise, 120 Insulation

F

O

R

M

Liquid Filled Padmounted

Mineral Oil

Bottom Entry, NEMA 3R Rated

24940GY/14400V Primary, 480Y/277 Secondary

Square D 2010 Efficiencies Square D 2016 Efficiencies

F

I

T

H –72.5”

W –86”

D – 70”

Weight –10,030 pounds

H –72.5”

W –80”

D – 66”


F

U

N

C

T

I

O

N

99.42% Efficient @ 50% Load

IZ – 5.75%

Core Loss 1942 Watts

Coil Loss 10488 Watts

BTU’s @ 50% Load 14,717


IZ – 5.75%

Core Loss 1773 watts

Coil Loss 7944

BTU’s@50% Load 12,179

31

Design Line 10, 1500 kVA VPI, 150 Rise, 45KV BIL, 220 Insulation

F

O

R

M

VPI, Power Dry, Substation Transformer

Close Coupled to Primary and Secondary Gear

NEMA 1 Indoor

4160 Delta Primary, 480 Wye Secondary

Square D 2010 Efficiencies Square D 2016 Efficiencies

F

I

T

H –94”

W –84”

D – 54”


H –100”

W –96”

D – 60”


F

U

N

C

T

I

O

N


IZ – 5.75%



BTU’s @ 50% Load 22,993


IZ – 5.75%



BTU’s @ 50% Load 17,118

32

Codes and Standard – Low Voltage Transformers • National Electrical Code

• NEMA ST-20

• NEMA TP1, TP2, TP3

33

NEC Updates

> NEC change 1.2kV units from 600 Volt Max to 1000 Volt Max

> 450.9 Ventilation

> 450.10 Grounding

> 450.11 Markings

> 450.12 Terminal wiring space

34

450.9 Ventilation

> The ventilation shall be adequate to dispose of the transformer full-

load losses without creating a temperature rise that is in excess of

the transformer rating

> Transformers with ventilation openings shall be installed so that the

ventilating openings are not blocked by walls or other obstructions

> The required clearances shall be clearly marked on the transformer

> Square D Low Voltage Units – all tested at ½” Clearance in alcove

November 1992 – UL 1561 was modified an mandated that the minimum

distance be 6 inches unless the manufactured alcove tested the units at a

different distance, Expect to see distances at less than 6” in the market

place with product being completely redesigned.

35

450.10 Grounding

> (A) Dry Type Transformer Enclosures. Where separate equipment grounding

conductors and supply-side bonding jumpers are installed, a terminal bar for all

grounding and bonding conductor connections shall be secured inside the transformer

enclosure. The terminal bar shall be bonded to the enclosure in accordance with

250.12 and shall not be installed on or over any ventilated portion of the enclosure.

36

450.11 Markings

(A) General. Each transformer shall be provided with a nameplate giving the following

information

(1) Name of Manufacturer

(2) Rated kilovolt amperes

(3) Frequency

(4) Primary and Secondary voltage

(5) Impedance of transformer 25kVA and Larger

(6) Required clearance for transformers with ventilated openings

(7) Amount and kind of insulating liquid where used

(8) Dry-Type transformer, temperature class for the insulation system

(B) Source Marking. A transformer shall be permitted to be supplied at the marked secondary

voltage, provided that the installation is in accordance with the manufacturer's instructions.

37

450.12 Terminal wiring Space

> Minimum wire bending space at fixed,

1000-volt and below terminals of

transformer line and load connections shall

be as required by 312.6

> TERMINAL:

(A) a conducting element of an equipment or a circuit

intended for connection to an external conductor

(B) a device attached to a conductor to facilitate

connection with another conductor

> Most transformers require that the

raceways be brought into the transformer

case in a certain area.

> This is usually the lower half of the

transformer case.

38

NEMA ST-20

> NEMA Publishes Reinstated NEMA ST 20-2014 Dry Type Transformers for General

Applications – June 2014

> The reinstated and revised edition of NEMA ST 20 applies to single-phase and polyphase dry-type

transformers (including autotransformers and non-current-limiting reactors) for supplying energy to

power, heating, and lighting circuits, and designed to be installed and used in accordance with the

National Electrical Code®. It also covers transformers with or without accessories having ratings of 1.2

kV class, 0.25 kVA through 4000 kVA

> NEMA ST 20 is one of the few standards in the marketplace that specifically addresses sound levels

for this particular type of transformer.

> C57-12.01 IEEE Standard General Requirements for Dry-Type Distribution and Power

Transformers Including Those with Solid- Cast and/or Resin-Encapsulated Windings

> This standard is intended as a basis for the establishment of performance, interchangeability, and

safety requirements of equipment described, and for assistance in the proper selection of such

equipment. Electrical, mechanical, and safety requirements of ventilated, nonventilated, and sealed

dry-type distribution and power transformers or autotransformers (single and polyphase, with a voltage

of 601 V or higher in the highest voltage winding) are described. The information in this standard

applies to all dry-type transformers

39

NEMA ST-20

> NEMA Publishes Reinstated NEMA ST 20-2014 Dry Type Transformers for General

Applications – June 2014

> The reinstated and revised edition of NEMA ST 20 applies to single-phase and polyphase dry-type

transformers (including autotransformers and non-current-limiting reactors) for supplying energy to

power, heating, and lighting circuits, and designed to be installed and used in accordance with the

National Electrical Code®. It also covers transformers with or without accessories having ratings of 1.2

kV class, 0.25 kVA through 4000 kVA

> NEMA ST 20 is one of the few standards in the marketplace that specifically addresses sound levels

for this particular type of transformer.

40

NEMA TP1, TP2, TP3

DOE Final Rules 10 CFR 429 and 431 > NEMA TP1

> Provides the basis for determining the energy

efficiency of certain single- and three-phase dry-

type and liquid-filled distribution transformers and

assists with the proper selection of such

equipment.

> NEMA TP2

> Standard Test Method for Measuring the Energy

Consumption of Distribution Transformers. The

document provides a standardized method for

measurement of distribution transformer loss to

achieve energy efficiency levels outlined in NEMA

publication TP 1, Guide for Determining Energy

Efficiency for Distribution Transformers

> NEMA TP3

> Defines the labeling of distribution transformers

tested to the efficiency levels specified in TP1

> 10 CFR 429

> Provisions for Statistical Sampling Plans for

Certification Testing

- 10 CFR 429.47

- 10 CFR 429.70

> APPENDIX C TO SUBPART C OF PART 429:

SAMPLING PLAN FOR ENFORCEMENT

TESTING OF DISTRIBUTION

TRANSFORMERS

> 10 CFR 431

> Subpart K—Distribution Transformers

> Appendix A to Subpart K of Part 431—Uniform

Test Method for Measuring the Energy

Consumption of Distribution Transformers

41

NEMA TP1, TP2, TP3

DOE Final Rules 10 CFR 429 and 431

> 10 CFR 429

> Provisions for Statistical Sampling Plans for

Certification Testing

- 10 CFR 429.47

- 10 CFR 429.70

> APPENDIX C TO SUBPART C OF PART 429:

SAMPLING PLAN FOR ENFORCEMENT

TESTING OF DISTRIBUTION

TRANSFORMERS

> 10 CFR 431

> Subpart K—Distribution Transformers

> Appendix A to Subpart K of Part 431—Uniform

Test Method for Measuring the Energy

Consumption of Distribution Transformers

42

Low Voltage Transformer Market Conditions • Harmonics (HMT and K-rated)

• Copper Windings

• Electrostatic Shields

• Efficiency Better Than Law

43

Harmonic Load Applications

K-Rated (1990 through now) Harmonic Mitigation Transformers

> Early 90’s UL 1561 determine method for

testing for harmonic loads

> UL Listing for 4, 9, 13, 20, 30

- Readily available from the Market 4 and 13

> Over the last 25+ years

> Reduction in Harmonic Profiles with

electronic equipment

> Impact of source impedance on K-factor on

Transformers

> K-7, is the maximum level seen by a 100%

load transformer

> K-9 rated should be the level to meet the

market conditions

> Leverage Drive Process for single phase

harmonic Loads

> 0°, 30°, 15°, 45° (-15°)

> Initial Launch 90’s, not successful –

Delta – Wye and HMT convert the tripplen

harmonics equally

> Never really accepted for 5th and 7th Harmonics

> Energy Impact added in 21st Century

> Increase Value over Delta-Wye

> Voltage Distortion lessen with HMT

> Should be K-rated, device sees harmonic

loads on the Secondary Windings

44

Delta to Wye 30° Shift Delta to ZigZag 0° Shift

> Primary wave form – No Tripplens > Primary wave form – No Tripplens

45

Copper Windings vs Aluminum Windings

> Truths

> Properly terminating line and load

connections is more difficult for aluminum-

wound transformers

> Aluminum wound transformers are lighter in

weight than copper wound equivalents

> Copper-wound transformers can be made

smaller than aluminum wound equivalents.

> Myths

> Aluminum-wound transformer terminations are

incompatible with copper line and load cables

> Line and load connections to copper-wound

transformers are more reliable than those to

aluminum wound transformers

> Aluminum-wound transformers have higher

losses because copper is a better conductor

> Aluminum-wound transformers have higher hot-

spot temperatures because copper is a better

thermal conductor X than aluminum

46

Electrostatic Shield

Transformers shall be supplied with quality, full width electrostatic shields resulting in a

maximum effective coupling capacitance between primary and secondary of 33

picofarads. With transformers connected under normal, loaded operating conditions,

the attenuation of line noise and transients shall equal or exceed the following limits:

Common Mode: 0 to 1.5kHZ - 120dB

1.5kHZ to 10kHZ - 90dB

10kHZ to 100kHZ - 65dB

100kHZ to 1MHZ - 40dB

Transverse Mode: 1.5kHZ to 10kHZ - 52dB



47


Transformers shall be supplied with quality, full width electrostatic shields resulting in a

maximum effective coupling capacitance between primary and secondary of 33

picofarads. With transformers connected under normal, loaded operating conditions,

the attenuation of line noise and transients shall equal or exceed the following limits:

Common Mode: 0 to 1.5kHZ - 120dB

1.5kHZ to 10kHZ - 90dB



Transverse Mode: 1.5kHZ to 10kHZ - 52dB



Above is DC testing and verification – completed in the late 80’s

48


Technology Allows for AC Testing of

the shield

Schneider Electric White paper

0150PD9603

AC testing has shown that shielding may have little value or no benefits when the secondary is grounded

per the NEC requirements. (Wye, ZigZag, and Center Tap Delta Secondaries)

Proper grounding practices, as well as placing isolation transformers as close as possible to loads, are two

major factors in providing high quality power to sensitive electronic equipment.

49

Better than the Law

> 2007 to 2016 – NEMA PREMIUM, CSL3

> Justified by the DOE Advance rule in July 2004

> What about in 2016

> DOE has concluded that the standards in today's final rule represent the maximum

improvement in energy efficiency that is technologically feasible and economically justified,

and would result in significant conservation of energy.

- 10,000 Designs at multiple Efficiency Levels

- All review at the Market Loading Conditions

Low Voltage 15 to 20% (Law still sets standard at 35%)

> Comparisons need to be to EL3 and EL2 – which become law in 2016

Not EL0 (which is the base – TP1 Levels)

> Before you agree to levels above

> Review the full FINAL RULE (102 page document)

> DOE to announce in 2016 if they will start reviewing Low Voltage – wait till they start there

anlyisis

low voltage distribution transformers - weat · 2015. 8. 19. · 12 distribution transformer means...

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