NOPR Rulemaking Stage

Framework

Document

PreliminaryA

n

alysis NOPR Final Rule Date Compliance Document a ys s Rule Date Date

Screening

EngineeringAnalysis

Markups for Equipment Price Determination

Market & Technology Assessment

Analysis

Energy Use and End Use Load

Life-CycleCost andPayback Period Analysis

End-Use LoadCharacterization

ShipmentsAnalysis

Manufacturer Impact Analysis

1 | Building Technologies Program 
Goals of the Engineering Analysis

• To evaluate design options that improve efficiency.• To characterize manufacturer selling price (MSP) versus 

efficiency for higher-efficiency distribution transformers.

Downstream An

Manufacturer Selling Price – Efficiency Relationship

• Life-Cycle Cost a

Payback Period 

cturer 

Price

• National Impact 

Manufac

Selling 

2 | Building Technologies Program 

Efficiency Level
Engineering Analysis:

Methodology

 Subdivide 10 equipment class groupings into 1

based on similar principles of design. Identify r

Choose Rep. 

Design Lines and 

Units

 Identify design option combinations to characte

spectrum of possible efficiencies. Select Higher Efficiency Design Options

 Identify materials prices, markups, labor require

other cost components for each design option c

 U O ti i d P S i (OPS) ft 

Develop Cost 

Inputs

Use Optimized Program Service (OPS) softwa

optimized designs based on several hundred A 

 Develop efficiency levels (ELs) that span the ra

Model Optimized 

Designs Based 

on A’s and B’s

Develop efficiency levels (ELs) that span the ra

efficiency from the baseline to the maximum tefeasible.

Develop ELs

Scale to 

3 | Building Technologies Program 

 Scale results to other equipment classes not an

Equipment Classes Not 

Analyzed
Engineering Design Lines and 

Representative Units

• Subdivide equipment classes into 14 engin

design lines based on similar principles of 

d t ti

Choose Rep. 

Design Lines and 

Units

an

d cons

truction.

– Five liquid-immersed,– Three LVDT, and

Select Higher 

Efficiency 

Design Options

– Six MVDT.

• Span a range of kVA ratings for which the 

Develop Cost 

Inputs

scaling rule would provide accurate results

• Select one re

presentative unit from each e

Model Optimized 

Designs Based 

on A’s and B’s

p 

design line. Develop ELs

Scale to 

4 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Liquid-Immersed Equipment Class to 

Design Line Mapping

Choose Rep. 

Design Lines and 

Units

Equipment Class Group 1

Liquid-Immersed,

Equipmen

Liquid

Select Higher 

Efficiency 

Design Options

Rectangular Round

Tank Tank

10

Single-Phase

kVA 

15

Thr

kVA

Develop Cost 

Inputs

101525

37.5

L 1

L 2

Rep Unit

15304575

112 5

Model Optimized 

Designs Based 

on A’s and B’s

5075

100

167

DL

DLRep Unit 112.5 150

225300500

Develop ELs

Scale to 

167250333500667

DL 3 Rep Unit

500750

10001500

2000

5 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed

667833

20002500
Liquid-Immersed Design Lines and 

Representative Units

uipment 

Class

esign 

LineType of Distribution Transformer kVA Range Representativ

Equ

C

De

LTransformer Range

1

Liquid-immersed, sin

glephase, 10

–167

50 kVA, 65°C, single-ph14400V 

primar

y, 240/12

1

g p ,

rectangular tank

p y, 

rectangular tank

2

Liquid-immersed, single-phase, round 

tank

10–167

25 kVA, 65°C, single-ph14400V primary, 240/12

tank round tank round tank

3 Liquid-immersed, single-phase 250–833 500 kVA, 65°C, single-p

14400V primary, 277V 

6 | Building Technologies Program 
Identify Transformer Design Option 

Combinations

• Select design option combinations.

– Vary core configurations, core steels, and wind

Capture most common designs and maximum 

Choose Rep. 

Design Lines and 

Units

– Capture most common designs and maximum 

Select Higher 

Efficiency 

Design Options Design Option Designs Consider

Wound core distributed gap;

Develop Cost 

Inputs Core Configuration (Type)

Wound core distributed gap;Stacked butt-lap;Stacked full miter;Step-lap miter;Stacked cruciform miter Model Optimized 

Designs Based 

on A’s and B’s

Stacked cruciform miter.

Core Configuration (Construction)

1-Phase: Shell and Core type.3-Phase: 3-legged, 5-legged and S

Develop ELs

Core Steels

Silicon steel: M12, M6, M5, M4, MDomain refined silicon steel: H-0 ZDMH (liquid-immersed).

Scale to Amorphous steel: SA1 (Dry-type 

7 | Building Technologies Program 

Winding materials Copper; Aluminum. Equipment Classes Not Analyzed
Identify Transformer Design Option 

Combinations (Continued)

Design Core Conductor Conductor Core/

Choose Rep. 

Design Lines and 

Units

Example of Design Option Combinations 

DL7: 75 kVA low-voltage dry-type, three-

Design

Option

Core

Material

Conductor

Primary

Conductor

Secondary

Core/

1 M12 Al Al 3-leg s2 M12 Cu Al 3-leg s

Select Higher 

Efficiency 

Design Options

3 M6 Al Al 3-leg s4 M6 Al Al 3-leg s5 M4 Cu Al 3-leg s

Develop Cost 

Inputs

6 M3

Al Al 3-leg s

7 M3 Al Al 3-leg 8 M3 Al Al 3-leg dis9

H

0 DR Al Al

3 leg s

Model Optimized 

Designs Based 

on A’s and B’s

9

H-0 DR Al Al

3-leg s

10 H-0 DR Al Al 3-leg 11 ZDMH Al Al 3-leg dis12 H-0 DR Cu Cu 3-le

g s

Develop ELs

Scale to 

8 | Building Technologies Program 

g

13 SA1 Al Al 5-leg dis14 SA1 Cu Cu 5-leg dis

Equipment 

Classes Not 

Analyzed
Engineering Analysis:

Markups and Labor Rate

• DOE determined materials prices and labor r

through conversations with manufacturers an

Choose Rep. 

Design Lines and 

Units

• DOE determined markups and labor rates fro

data, SEC filings, and manufacturer interview

Select Higher 

Efficiency 

Design Options

Develop Cost 

Inputs

Markup / Cost Input Markup Notes

Scrap and handling

2.5 % Standard scrap and hand

materials

15% P f bi t d h Model Optimized 

Designs Based 

on A’s and B’s

Scrap and handling 1.5 % Prefabricated amorphous 

4.0 % Additional scrap on fully m

Factory overhead 12.5 % Applied to materials

Develop ELs

Shipping $ 0.28 / pound Added prior to profit mark

4–8% of MSP

Fully-burdened hourly labor rate Scale to $ 51.52 Applied to total labor hou

9 | Building Technologies Program 

labor rateNon-production 25 % Applied to total cost for S

warranty/risk provisions, a

Equipment Classes Not Analyzed
Engineering Analysis:

Markups and Labor Rate

• For large (1500 kVA or greater) dry-type desig

amorphous core, DOE accounted for additionahardware costs.

Choose Rep. 

Design Lines and 

Units

Select Higher 

Efficiency 

Design Options

Cost Factor Additional Amount per Design Ration

E t h dli 

Develop Cost 

Inputs

Labor 10 hours Extra handling re

large, fragile amAdditional bracin

Model Optimized l d i t 

Designs Based 

on A’s and B’s

Hardware $230 to $330 large designs to 

and prevent shoproblems.

Develop ELs

Scale to 

10 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Engineering Analysis:

Modeling Optimized Designs

• Optimized Program Service (OPS) software c

design runs.

Choose Rep. 

Design Lines and 

Units

• As an input to the OPS software, economic p

(A and B values) are varied to simulate a ran

Select Higher 

Efficiency 

Design Options

customer orders, creating a database of trandesigns. Develop Cost Inputs

• Approximately 2,500 unique designs for each 

fourteen representative units within each of tdesign lines.

Model Optimized 

Designs Based 

on A’s and B’s

Develop ELs

Scale to 

11 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Engineering Analysis:

Modeling Optimized Designs

• OPS design software output includes:

– Construction and winding instructions for the 

Choose Rep. 

Design Lines and 

Units

(e.g., core dimensions, high- and low-voltage locations, insulation, cooling ducts, and labor

– Bill of materials and electrical analysis report.

Select Higher 

Efficiency 

Design Options

• Material, labor costs and markups are combi

determine the manufacturer’s selling price (M

Develop Cost 

Inputs

• Temperature-corrected efficiency determined 

software electrical analysis report.

Model Optimized 

Designs Based 

on A’s and B’s

Develop ELs

Scale to 

12 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Engineering Analysis:

Symmetric Core Designs

• DOE was unable to identify a company that co

symmetric core designs.

Choose Rep. 

Design Lines and 

Units

• DOE gathered information on symmetric cores 

manufacturer interviews, published literature, a

d i id d b f t

Select Higher 

Efficiency 

Design Options

designs provided by manufacturers.

– Using these data sources, DOE roughly estima

efficiency relationship of symmetric core design

Develop Cost Inputs

• DOE did receive limited design data from man

symmetric core transformers, and may issue s

to the extent that it is able.

Model Optimized 

Designs Based 

on A’s and B’s

to the extent that it is able.

Develop ELs

Scale to 

13 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Engineering Analysis:

Develop efficiency Levels

• DOE identified efficiency levels (ELs) that spa

distribution transformer efficiencies from the ba

maximum technologically feasible efficiency

Choose Rep. 

Design Lines and 

Units

maximum technologically feasible efficiency.

• Factors DOE considered in setting ELs:

Select Higher 

Efficiency 

Design Options

Develop Cost 

Inputs Harmonization across single-phase and the p

kVA equivalent three-phase design lin

Model Optimized 

Designs Based 

on A’s and B’s Equally spaced efficiency increment

q p g

Develop ELs Benchmark efficiency levels (e.g., NEMA P

Scale to 

14 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Engineering Analysis:

Modeled Designs from DL1

Rep Unit from DL1: 50 kVA liquid-immersed, single-phase, pad

$4,000 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 

$3,500 $3,000 

Selling Price ($)

$2,500 

Manufacturer M5_CuA

M3_AlAM3_CuAM2_AlAM2_CuA

$2,000 ZDMH_A

ZDMH_CSA1_AlASA1_CuCSLs

15 | Building Technologies Program 

$1,500 

99.00% 99.10% 99.20% 99.30% 99.40% 99.50% 

Efficiency at 50% Load, Temperature Corrected
Developing Trial Standard Levels for 

the NOPR

• If DOE issues a NOPR, it will select trial stand

(TSLs) based on groupings of ELs, such as:

P h h i ti i i LCC d 

Choose Rep. 

Design Lines and 

Units

–

P

e

r-p

hase 

harmonization, minimum LCC, an

d 

• These TSLs may consider any interaction betw

Select Higher 

Efficiency 

Design Options

equipment classes.

• DOE will select its 

pro

posed standard level in 

Develop Cost 

Inputs

p p

Model Optimized from the list of TSLs developed. Designs Based 

on A’s and B’s

Develop ELs

Scale to 

16 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Medium-Voltage Dry-Type Equipment 

Class to Design Line Mapping

Medium-Voltage Dry-Type, Single-Phase• Single-phase MVDT units have low unit shipments a

capacity shipped.

Choose Rep. 

Design Lines and 

Units capacity shipped.

• Rather than directly analyzing these units, DOE sca

units by dividing the kVA rating of three-phase MVDthree.

Select Higher 

Efficiency 

Design Options

Develop Cost 

Inputs Three-Phase Rep Unit 

kVA

Single-Phas

Unit k

Model Optimized 

Designs Based 

on A’s and B’s

300 100

1500 500 Scales To...

Develop ELs

Scale to 

2000 667

17 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed
Engineering Analysis:

Scaling Results

• DOE scaled the total losses (TL) from a repre

to other unanalyzed kVA ratings (S) within a dusing the 0.75 Scaling Rule:

Choose Rep. 

Design Lines and 

Units g g

TL1 = TL0 x (S1 / S0)0.75

Select Higher 

Efficiency 

Design Options

• Costs of construction and losses can be scale

design parameters are held constant, includin

frequency magnetic flux density current dens

Develop Cost 

Inputs

– frequency, magnetic flux density, current dens

insulation level. Model Optimized Designs Based 

on A’s and B’s

Design Line 7 (LVDT, 3-phase, 15 – 150 kV

Develop ELs 75 kVA Representative Unit 75 kVA Representative Unit

15 30 45 75 112 5 

Scale Results

Scale to 

18 | Building Technologies Program 

15

kVA

30

kVA

45

kVA

75

kVA

112.5

kVA

Equipment 

Classes Not 

Analyzed
19 | Building Technologies Program 
Backup Slides

Backup Slides

20 | Building Technologies Program 
Liquid-Immersed Equipment Class to 

Design Line Mapping

Equipment Class 1

Li

quid-Immersed,

Equipm

Li

quid

Choose Rep. 

Design Lines and 

Units

Rectangular Round

Tank Tank

q ,

Single-Phase

kVA 

15

q

Thre

kVA Select Higher Efficiency 

Design Options

101525

37.5

L 1

L 2

Rep Unit

15304575

112 5

Develop Cost 

Inputs

37.5

5075

100

167

DL

DL Rep Unit 112.5 150

225300

Model Optimized 

Designs Based 

on A’s and B’s

167250333500

DRep UnitL 3

500750

10001500

Develop ELs

Scale to 

21 | Building Technologies Program 

667833

D

20002500

Equipment 

Classes Not 

Analyzed
Low-Voltage Dry-Type Equipment 

Class to Design Line Mapping

Equipment Class 3

Dr

y-Type, Low Volta

ge,

Equipmen

Dry-Type, Lo

Choose Rep. 

Design Lines and 

Units

kVA Design Line

15

y yp g

Single-Phase kVA D

15

Three-P

Select Higher 

Efficiency 

Design Options

1525

37.5

Rep Unit

304575 R

Develop Cost Inputs

5075

100

DL 6

112.5

150225

Model Optimized 

Designs Based 

on A’s and B’s

100167250333

300500750

Develop ELs R

Scale to 

22 | Building Technologies Program 

333 1000 Equipment Classes Not 

Analyzed
Medium-Voltage Dry-Type Equipment 

Class to Design Line Mapping

Choose Rep. 

Design Lines and 

Units

EC 6 EC 8 E

20-45kV 46-95kV >

Dry-Type, Medium Voltage, Three-Phas

Select Higher 

Efficiency 

Design Options

15 30 45 

Develop Cost 

Inputs

75 

112.5 

150 

DL 9

DL 11

Model Optimized 

Designs Based 

on A’s and B’s

225300500750

Rep Unit Rep Unit Rep 

Develop ELs

Scale to 

750

100015002000

DL 10

D

Rep Unit Rep Unit

L 12

Rep 

23 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed

20002500

D

DRep 
Liquid-Immersed Design Lines and 

Representative Units

nt Equipme

Class

Design 

LineType of Distribution Transformer kVA Range Representativ

E

1

Liquid-immersed, single-phase, rectangular tank

10–167

50 kVA, 65°C, single-ph14400V primary, 240/12rectangular tank

1

2

Liquid-immersed, single-phase, round tank

10–167

25 kVA, 65°C, single-ph

14400V primary, 120/24round tank

Liquid

-immersed 500 kVA 65

°C single

-p

3 Liquid immersed, single-phase 250

–833 500 kVA, 65

C, single p

14400V primary, 277V 

24 | Building Technologies Program 
Liquid-Immersed Design Lines and 

Representative Units

pment 

lass

esign 

LineType of Distribution Transformer kVA Range Re

presentativ

Equi

Cl

De

LTransformer Range

p

4 Liquid-immersed, 15

–500

150 kVA, 65°C, three-p12470Y/7200V primary 

2

4 three-phase 15 500 12470Y/7200V primary

secondary

5 Liquid-immersed, three

-phase 750–2500

1500 kVA, 65°C, three-24940GrdY/14400V pri

480Y/277V d three phase 480Y/277V secon

dary

25 | Building Technologies Program 
Low-Voltage Dry-Type Design Lines 

and Representative Units

nt Equipme

Class

Design

LineType of Distribution Transformer kVA Range Representative 

3 6 Dry-type, low-voltage, single-phase 15–333 25 kVA, 150°C, single-ph

480V primary, 120/240V s10kV BIL

75 kVA 150

°C three pha

4

7 Dry-type, low-voltage, three-phase 15–150 75 kVA, 150

C, three

-pha

480V primary, 208Y/120V 10kV BIL

300 kVA 150

°C three

-ph

8 Dry-type, low-voltage, three-phase 225–1000 300 kVA, 150

C, three ph

480V Delta primary, 208Ysecondary, 10kV BIL

26 | Building Technologies Program 
Medium-Voltage Dry-Type Design 

Lines and Representative Units

quipment 

Class

Design 

LineType of Distribution Transformer kVA Range Representativ

Eq

D

6

9

Dry-type, mediumvoltage, three-phase, 20-45kV BIL

15–500 300 kVA, 150°C, three-phase

Delta primary, 480Y/277V se

6

10

Dry-type, mediumvoltage, three-phase, 20-45kV BIL

750–2500 1500 kVA, 150°C, three-pha

primary, 480Y/277V seconda

Dry-type, medium- 300 kVA 150°C three-phase 

8

11 voltage, three-phase, 46-

95kV BIL

15

–500 300 kVA, 150

C, three phase

primary, 480Y/277V seconda

12

Dry-type, mediumvoltage, three-phase, 46-

95kV BIL

750–2500 1500 kVA, 150°C, three-phas

primar

y, 480Y/277V seconda

95kV BIL py 

10 13 (A & B) Dry-type, medium- voltage, three-phase, 96- 150kV BIL 225–2500

300 kVA, 150°C, three-phaseprimary, 480Y/277V seconda2000 kVA, 150°C, three-phas

i 480Y/277V d 

27 | Building Technologies Program 

150kV BIL primary, 480Y/277V secon

da
Engineering Analysis: Materials 

Prices for Core Steels

Material Units 2010 Price [2010$] 2006 Pri

[2010

M12 core steel $/lb 1.03 0

M6 core steel $/lb 1.46 0M5 core steel $/lb 1.51 0M4 core steel $/lb 1.59 1M3 core steel $/lb 1.88 1M3 core steel ( M3 core steel (Lite Carlite Carlite) $/lb 1.95 1

M2 core steel $/lb 2.00 1

M2 core steel (Lite Carlite) $/lb 2 10 1 M2 core steel (Lite Carlite) $/lb

2.10 1

ZDMH (mechanically-scribed core steel) $/lb 2.05 1H-0 DR core steel (laser scribed) $/lb 2 06 1 

28 | Building Technologies Program 

$/lb

2.06 1

SA1 (amorphous) finished core, volume production $/lb 2.38 1
Engineering Analysis: Materials Prices for 

Liquid-Immersed Design Lines

Material Units 2010 Price [2010$] 2006 P

[201

Conductor and Miscellaneous Prices

Copper wire, formvar, round #10-20 $/lb 4.87 

Copper wire, enameled, round #7-10 $/lb 4.84 

Copper wire, enameled, rectan

gular sizes $/lb 4 97 

pp , , g

4.97

Aluminum wire, formvar, round #9-17 $/lb 3.07 

Aluminum wire, formvar, round #7-10 $/lb 2.57 

Copper strip, thickness range 0.02-0.045 $/lb 4.97 

Copper strip, thickness range 0.030-0.060 $/lb 4.97 

Aluminum strip, thickness range 0.02-0.045 $/lb 2.08 

Aluminum strip, thickness range 0.045-0.080 $/lb 2.08 

Kraft insulating paper with diamond adhesive $/lb 1.52 

Mineral oil $/gal 3 35 29 | Building Technologies Program Mineral oil $/gal

3.35 

Tank Steel $/lb 0.38 
Engineering Analysis: Materials 

Prices for Dry-Type Design Lines

Material Units 2010 Price 2006 P

Conductor and Miscellaneous Prices

[2010$] [201

Copper wire, rectangular 0.1 x 0.2, Nomexwrapped $/lb 4.52 

Aluminum wire, rectangular 0.1 x 0.2, Nomex $/lb 2 97 Aluminum wire, rectangular 0.1

x 0.2, Nomex

wrapped $/lb

2.97

Copper strip, thickness range 0.02-0.045 $/lb 4.97 

Aluminum strip, thickness range 0.02-0.045 $/lb 2.08 

Nomex insulation $/lb 24.50 1

Cequin insulation $/lb 5.53 

Impregnation $/ l ga 22 55 . 1Winding combs $/lb 12.34 

Enclosure Steel $/lb 0.38 

30 | Building Technologies Program 
Developing Trial Standard Levels for 

the NOPR

Choose Rep. 

Design Lines and 

Units

• Illustration of how TSLs are selected based on 

ELs:

C bi li id i d d i li i 

Select Higher 

Efficiency 

Design Options

–

Combine liquid

-immerse

d

design lines using m

available that does not use amorphous metal.

Develop Cost 

Inputs Design Line EL

Model Optimized 

Designs Based 

on A’s and B’s

1 22 23

3

T

Develop ELs

Scale to 

4 25

2

31 | Building Technologies Program 

Equipment 

Classes Not 

Analyzed

5

2
NOPR Rulemaking Stage

Framework

Document

PreliminaryA

n

alysis NOPR Final Rule Date Compliance Document a ys s Rule Date Date

Screening

EngineeringAnalysis

Markups for Equipment Price Determination

Market & Technology Assessment

Analysis

Energy Use and End Use Load

Life-CycleCost andPayback Period Analysis

End-Use LoadCharacterization

ShipmentsAnalysis

Preliminary Manufacturer Impact Analysis

32 | Building Technologies Program 
Purpose

• Market and Technology Assessment

– Characterize the distribution transformer market and industry Characterize the distribution transformer market and industry

– Identify the technology options to improve distribution transfo

efficiency.

– Establish equipment classes Establish equipment classes.

• S i Ali Screening Analysis

– Screen out technology options that DOE will not consider in t

engineering analysis for distribution transformers based on se

33 | Building Technologies Program 
Relationship of Market and Technology 

Assessment to Other Analyses

Market and Technology 

Assessment Equipment Cl

Th l ec

hno

logy options t i ffi i to 

improve effic

iency

Screening Analysis

Design options to improve efficiency

Engineering Analysis

34 | Building Technologies Program 
Equipment Classes

• DOE divides covered equipment into classes by:

– The Type of energy used,– The Capacity, or– Any performance-related features that affect consumer utility 

efficiency.

• DOE considered 10 equipment class groupings by dividing 

popul i f di ib i f b d lation of distribution transformers based upon:

– Type of transformer insulation: liquid-immersed or dry-type,– Number of phases: single or three,– Voltage class: low or medium (for dry-type units only), and– Basic impulse insulation level (BIL): (for MVDT units only).

35 | Building Technologies Program 
Distribution Transformers 

Equipment Class Groupings

There are 115 discrete kVA ratings across the ten equipment class gr

ECG Ins lation Ins

ulation Phases Voltage Voltage BIL 

1 Liquid-Immersed Single Medium --- 2 Liquid-Immersed Three Medium --- 3 Dry-Type Single Low --- 4 Dry-Type Three Low --- 5

DryType Si l ng

e M di e um 20-45 kV BIL 45 kV BIL 

6 Dry-Type Three Medium 20-45 kV BIL 7 Dry-Type Single Medium 46-95 kV BIL 8 Dry-Type Three Medium 46-95 kV BIL 9 Dry-Type Single Medium >96 kV BIL 

10 Dr

y-Type Three

Medium >96 kV BIL 2

36 | Building Technologies Program 

0

y ype ee ed u 96
Distribution Transformers

2009 Industry Shipments

Equipment Class Grouping Units Shipped 

1. Liquid-immersed, medium-voltage, single-phase 683,726 2. Liquid-immersed, medium-voltage, three-phase 49,739 3 Dry . Dry-type low type, low-voltage single voltage, single-phase 17 740 , 4. Dry-type, low-voltage, three-phase 206,929 5. Dry-type, medium-voltage, single-phase, 20-45 kV BIL 709 6. Dry-type, medium-voltage, three-phase, 20-45 kV BIL 522 7. Dry-type, medium-voltage, single-phase, 46-95 kV BIL 546 8. Dry-type medium type, medium-voltage three voltage, three-phase 46 phase, 46-95 kV BIL 95 kV BIL 2 074 , 9. Dry-type, medium-voltage, single-phase, 

≥ 96 kV BIL 202 

10. Dry-type, medium-voltage, three-phase, 

≥ 96 kV BIL 1,286 

37 | Building Technologies Program 

TOTAL 963,473 
Technology Options

Technology Option Material / Concept

Aluminum (wire and sheet)

Conductor Materials for Coils

(wire and sheet)

Copper (wire and sheet)

Core Materials

Cold-Rolled High Silicon (CRHiSCRHiSi Domain-Refined Steels

Amorphous Materials in Wound 

Geometry Modifications Adjust the cross-sectional area o

/ dt dj t lt 

Geometry Modifications core/conductor, or adjust volts p

Symmetric Core Designs Continuously wound cores with 

radial symmetry for three-phase 

A transformer is replaced by thre

38 | Building Technologies Program 

Core Deactivation Technology

A transformer is replaced by thre

transformers that are (de)activatresponse to changes in load dem
Technology Assessment:

Symmetric Core Designs

• “Symmetric Core” designs are three-phase 

designs that use a continuously wound 

core with 120 ith 120

° radi l t a symme

try.

• Advantages include lowered: weight, 

volume, no-load losses, noise, vibration, stray magnetic fields, inrush current, and power in the third harmonic.

• Best suited for delta-delta or delta-wye 

connections, though zero-sequence fluxes 

associated with wye-wye connections can be mitigated by a delta-connected tertiary winding.

S L d 

39 | Building Technologies Program 

Source: Lun

d

Electromagnetic P

http://www.hexaformer.co
Technology Assessment:

Core Deactivation Technology

• Reduces core losses by using a system of smaller transfo

replace a single larger transformer replace

a single, larger transformer.

– Example: Three 25 kVA transformers in parallel replace a 7

transformer.

• Control unit can activate and deactivate component transf

depending on the loading demands.

– Optimizes combination of transformers at given load.

• DOE is only aware of this technology in LVDT distribution 

transformers.

– Medium-voltage core deactivation systems have not been p

commercially, and pose difficulties for switching within the prsecondary connections.

40 | Building Technologies Program 

• Best suited for applications with low loading demands.
Core Deactivation Technology

Load vs. Efficiency

989997

ncy % Core Deactivation System

9596

EfficienCore Deactivation System Traditional Transformer Desi

T P d L di

9394

Test 

Proce

dure 

Loadin

g

This figure is for illustrative purposes only and is not based 

5 15 25 35 45 55 65 75 8

Percentage of Full Rated Load

41 | Building Technologies Program 

This figure is for illustrative purposes only, and is not based 

DOE research
Technology Assessment:

Core Deactivation Technology

• While core deactivation technology could save energy ove

cycle, these energy savings may not be captured by the c

p p yg g rocedure s

pecifyin

g a sin

gle load factor.

• A weighted-average loss calculation using various loading

better ca

p gy gy g p ture this technology’s energy savin

gs 

potential.

Example:

Loading 

(%)

Losses 

( )

Single Loading Point,

(%)

Weighte

(%)

(

W

) Load Frequency (%) Load Fre

0 200.0 0 

15 222.5 0 35 322.5 100 50 450.0 0 75 762 5

0

42 | Building Technologies Program 

75 762.5

0

Average Losses 322.5 3
Technology Assessment:

Core Deactivation Technology

• DOE is not considering core deactivation technology in the 

setting standards, but may explore doing so in the future.

– Scale each design to 1/3 its kVA and group them in sets of thre

Scale each design to 1/3 its kVA and group them in sets of thre

– Account for additional cost and weight of the core deactivation – Analyze each core deactivation system using various loading s

• Core deactivation systems using non-identical component tr

– Each component transformer requires a similar winding design 

i d t h l di impe

dance a

t eac

h loading.

• Based on conversations with manufacturers, core deactivat

MVDT has additional challenges.

43 | Building Technologies Program 
Screening Analysis

Purpose

• Screen out technology options that DOE will not consider in 

engineering analysis for distribution transformers.

Approach

Technological feasibility

• DOE will evaluate each technology option based on the follo

Practicability to manufacture, install, and service

Technological feasibility

Impacts on health or safety

Adverse impacts on equipment utility or availability 

consumers

44 | Building Technologies Program 

Impacts on health or safety
Technology Options Screened 

Out of the Analysis

Technology Option Excluded Screening Criteria

Silver as a Conductor Material Practicabilit

y ,

 to manufacture, instal

High-Temperature Superconductors

Technological feasibility; Practicability to manufacture, instal

Amorphous Core Material in Stacked Core Configuration

Technological feasibility; Practicability to manufacture, instal

Carbon Composite Materials Carbon Composite Materials

for Heat Removal Technological feasibilityHigh-Temperature Insulating Material Technological feasibility

Solid-State (Power Electronics) Technology

Technological feasibility;Practicability to manufacture, instalservice.

45 | Building Technologies Program 

Nanotechnology Composites Technological feasibility
Engineering Validation

• DOE may g make available detailed design informatio

certain design lines and efficiency levels to allow manufacturers to compare with designs of their own

• DOE may invite manufacturers to submit similar des

information for their own designs. Such information, 

submitted to a Department contractor would be kept submitted to a Department contractor, would be kept 

confidence.

46 | Building Technologies Program