DOE Distribution Transformer Efficiency Regulation Evaluation of Impact on the Industry Carlos...

DOE Distribution Transformer Efficiency Regulation

Evaluation of Impact on the Industry

Carlos GaytanManager of Engineering

Distribution Transformers

April 29, 2008

2 © Prolec GEproprietary information

Agenda

Efficiency Calculations

Impact on Materials

Impact on Manufacturers

Impact on Customers

Customer Purchasing Practices

Outstanding Issues / Concerns

Summary and Next Steps



Efficiency = Power OUT / Power IN

Where:

%EFF = Efficiency means the ratio of the useful power to the total power input; for DOE Rule it is calculated at 50% Load

kVA = Transformer Capacity in kilo Volt Ampere

NL = No Load (Core) Losses corrected to 20°C

LL = Load Losses corrected to 85°C

0.91 = Load Loss Temperature correction from 85°C to 55°C

)1000/)5.0*91.0*((5.0*

5.0**100%

2LLNLkVA

kVAEFF



)/1000)]0.5 x 0.91 x LL((NL0.5 0.5/[kVA xkVA x x 100%EFF 2No Load Losses represent a critical portion of the

Transformer Efficiency

)1000/)5.0*91.0*((5.0*

5.0**100%

2LLNLkVA

kVAEFF

No Load Loss Impact25 kVA 1 Phase Designs having the same Total Losses

at 100% Load / 85°C

98.00

98.10

98.20

98.30

98.40

98.50

98.60

98.70

98.80

98.90

99.00

99.10

99.20

0 0.2 0.4 0.6 0.8 1 1.2

NL / LL Ratio (85°C)

Tr

ansf

orm

er E

ffici

ency

(%

)

Efficiency @ 100% Load / 85°C

Efficiency @ 50% Load / 55°C

DOE Minimum Efficiency

98.44%

98.91%

NL/LL=0.182


Efficiency CalculationsExamples of No Load Loss Impact

Two 25 kVA 1-Phase Designs with Same Efficiency at 100% Load are evaluated at 50% load (DOE basis):

• Design #1: NL=75W, LL=325W, TL=400W (NL/LL=0.23)

• Design #2: NL=55W, LL=345W, TL=400W (NL/LL=0.16)

)1000/)5.0*91.0*32575((5.0*25

5.0*25*100%

2EFF

%82.98% EFF Does Not Meet DOE Rule of 98.91%

)1000/)5.0*91.0*34555((5.0*25

5.0*25*100%

2EFF

%94.98% EFF Meets DOE Rule of 98.91%


Efficiency CalculationsLoad Loss Impact

25 kVA Single Phase Designs

97.50

97.70

97.90

98.10

98.30

98.50

98.70

98.90

99.10

99.30

99.50

Load Losses

Eff

icie

nc

y

Effic @100% & 85°C

Effic. @ 50% & 55 °C

DOE


Loss Differential for 0.01 Percent Change in EfficiencySingle Phase 10 to 833 kVA

and Three Phase 15 to 2500 kVA

0

0.5

1

1.5

2

2.5

98.00 98.20 98.40 98.60 98.80 99.00 99.20 99.40 99.60

Efficiency

% R

educ

tion

of L

osse

s ne

eded

for

0.0

1 in

crem

ent

in

Effi

cien

cy

Delta (%) 1Ph

Delta (%) 3Ph

Efficiency CalculationsEfficiency vs Losses



Around 50% of present designs available already meet the Efficiency Levels of the DOE Rule

Percent of available designs that meet DOE Rule

0

10

20

30

40

50

60

10 15 25 37.5 50 75 100 167

kVA Rating

Pe

rce

nt


Impact on MaterialsCore Material:

• Silicon Steel – M5(12 mil), M4(11 mil), M3 and M0H (9 mil), M2(7 mil) As efficiency of material improves total market volume decreases Worldwide limited supply of Grain Oriented Silicon Steel 5-year cost increase = 65% M3, M2 or better grades will become the most popular for DOE compliance

• Amorphous Metal Supply is tight, price flat in last 5 years Not an option for a significant conversion from Silicon Steel

Conductor Material:• Copper Wire

5-year cost increase = 240% Preferred material for High Voltage Windings

• Aluminum 5-year cost increase = 20% Preferred for LV windings; limited application for HV windings


Published Typical Losses of different Core MaterialsAt 1.5 Tesla / 60 Hz, (except for SA1 which is at 1.3 Tesla)

SA1 (Amorphous)

1 mil

M2, 7 mil M0H, 9 milM3, 9 mil

M4, 11 mil

M5 12 mil

M6, 14 mil

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1Core Material

Lo

sse

s (W

/kg

)

0.30

1.27

0.820.84

0.89

1.00

1.09

Impact on Materials

“M3 or Better” Grade Required to Meet DOE


NIPPON STEELJapan13%

JFEJapan

9%

AK SteelUSA15%

TKES/W. Eur.12%Cogent/W. Eur.

4%

East Europe2%

Viz StalRussia

17%

AcesitaBrazil

2%

POSCOS.Korea

12%

AlleghenyUSA4% Wuhan/China

13%

EBG/India0%

Total = 2.1 Million (MT)

2007 World Installed Production of Grain Oriented Silicon Steel*

* Data Courtesy of Sumitomo Corporation

Impact on Materials


PoscoS. Korea

23%

JFEJapan19%

TKES/ W. Eur.17%

AK SteelUSA8%

COGENTW. Eur.

1%

Nippon SCJapan32%

2007 World Installed Production of Hi B Silicon Steel*

Total = 0.64 Million (MT)* Data Courtesy of Sumitomo Corporation

Impact on Materials


World Installed Capacity of Grain Oriented Silicon Steel*(Thousands of MT)

400 400 400 410 440

60 75 120250 250130

200

200

400

160

230

240

250

250

250

100

110

111

111

114

310

310

330

330

380

230

230

270

304

320

80

80

80

90

90

130

0

0

40

30

30

30

40

40

0

500

1000

1500

2000

2500

2004 2005 2006 2007 Proj 2008Year

Acesita

Alsco

AKS

Russia

Other European

TKES

Baoshang

Wuhan

Posco

Japan

* Data Courtesy of Sumitomo Corporation

Impact on Materials

75%+ of Growth in Capacity in Asia; intended for domestic market


Manufacturer Key Issues:

• Amorphous Material

Possible difficulty of access to the technology; limited sourcing options

The high level of capital equipment investment required (rendering obsolete a large portion of the equipment used in the liquid-immersed industry, particularly core-cutting equipment and annealing furnaces)

• Core steel price volatility and uncertainty

• Dimensional and physical constraints

Meeting DOE efficiency standard and their customers’ dimensional and physical constraints simultaneously



Manufacturer Key Issues:

•Backsliding

Market may move from a highly customized market, to a commoditized market

Customized designs become less common

•Testing Methods and Systems

Manufacturing Process capabilities with Max. target Std. Deviation of 4%

The bigger the sample size, the closer the mean has to be to the Required Efficiency

Test Equipment Accuracy

•Design Optimization Customers’ response to DOE Rule

Will buyers purchase on Minimum Efficiency only or include a TOC evaluation?

Design optimization processes will change in response to purchasing practices



Impact on Customers

• For this rulemaking, DOE identified rural electric cooperatives and municipal utilities as transformer consumer subgroups that could be disproportionately affected

• NRECA commented that standards may encourage some utilities to stop evaluating transformer purchases for efficiency because the small differences between the energy savings and costs of evaluated and standard compliant transformers may no longer justify the cost of performing evaluations

• Impact to Customers of DOE efficiency standard will be proportional to their present purchasing practice


Impact on Customers

• For Non-Evaluated Market:Expected Price Increase of 15% to 20%Weight Difference of –5% to +10%

• For Mid-Evaluated Segment (e.g., A=$3.00; B=$1.00):Expected Price Increase of 5% to 10%Weight Difference of 0% to +5%

• For High-Evaluated Segment (e.g., A>$4.50; B>$1.50):Typical current offerings meet or exceed DOE minimum efficiencies

DOE Impact on Designs Quoted

)/1000)]0.5 x 0.91 x LL((NL0.5 0.5/[kVA xkVA x x 100%EFF 2Equivalent A & B factors will be driven by NL/LL ratio to meet

DOE Min. Efficiency


Customer Purchasing PracticesCurrent Purchasing Practices:

• Non-Evaluated Decision based on Lowest Price meeting ANSI/IEEE Standards

Leads to Low Efficiencies

• Total Owning Cost (TOC) Loss Evaluation TOC = (NL × A) + (LL × B) + Price

where:

o TOC = total owning cost ($),

o NL = no-load loss (Watts),

o A = equivalent first-cost of no-load losses ($/Watt),

o LL = load loss at the transformer’s rated load (Watts),

o B = equivalent first-cost of load losses ($/Watt), and

o Price = bid price (retail price)($).

TOC with Band of Equivalence (BoE)

• Efficiency Standards Evolution Energy Star ®

NEMA TP 1


TOC and Band of Equivalence (BoE) ConceptsCustomer Purchasing Practices

Total Losses

$Cost of Losses

Transformer Cost

Total Owning Cost

3% BoE

~4 - 6 % lower First Cost

Lowest TOCDesign

A higher TOCdue to a 3% BoE, leads us to a ...

... lower First Cost Transformer, roughly 4-6%

$

$


Customer Purchasing PracticesPurchasing Practices in a DOE Rule environment:

• For Non-Evaluated Segment:DOE Min. Efficiency will result in lower loss designsPurchase on lowest price from compliant bids?

• For Mid-Evaluated Segment (e.g., A=$3.00; B=$1.00):DOE Min. Efficiency will typically result in lower loss designPurchase Lowest Price only, or TOC, or TOC with BoE?

• For High-Evaluated Segment (e.g., A>$4.50; B>$1.50):Some DOE designs could result in less efficient, higher TOC unitsCustomers may choose to continue with TOC evaluations


• Multiple winding connections

Dual Voltage

120/240 V on the secondary.

• Efficiency must be measured on the winding connection that produces the highest losses.

• This requirement imposes a significant additional burden on manufacturers

Outstanding Issues / Concerns


Summary and Next Steps

From a Manufacturer’s Perspective:

• Understand how customers will purchase in a DOE standards environment

• Impact on Design Optimization Programs based on minimum efficiency and lowest material cost

• Review of standard materials

• Impact of global supply chain

• Flexibility of manufacturing and test processes

• IEEE Transformer Committee – assess impact on total industry


Thank You!

Carlos GaytanManager of EngineeringDistribution TransformersEmail: [email protected]

April 29, 2008


Bibliography.

10 CFR 431 Part III Energy Conservation Program for Commercial Equipment: Distribution Transformers Energy Conservation Standards; Final Rule. Issued Oct 12, 2007

10 CFR 431 Part III Energy Conservation Program for Commercial Equipment: Test Procedures for Distribution Transformers; Final Rule. Issued Apr 27, 2006

EERE Appliances and Commercial Equipment Standards, Distribution Transformers Web Page, last consulted on 12th Feb 2008.http://www.eere.energy.gov/buildings/appliance_standards/commercial/distribution_transformers.html

EERE Appliances and Commercial Equipment Standards, Technical Supporting Documentation for Final Rule (Distribution Transformers)http://www.eere.energy.gov/buildings/appliance_standards/commercial/distribution_transformers_fr_tsd.html

AK Steel Product Catalog, 2007

Personal communications with NEMA.

Report on Global Production of Silicon Steel by Sumitomo Corporation

DOE Distribution Transformer Efficiency Regulation Evaluation of Impact on the Industry Carlos...

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