1. No category

DOE Distribution Transformer
Efficiency Regulation
Evaluation of Impact on the Industry
Carlos Gaytan
Manager of Engineering
Distribution Transformers
April 29, 2008
Agenda
 Efficiency Calculations
 Impact on Materials
 Impact on Manufacturers
 Impact on Customers
 Customer Purchasing Practices
 Outstanding Issues / Concerns
 Summary and Next Steps
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Efficiency Calculations
Efficiency = Power OUT / Power IN
100 * kVA* 0.5
% EFF 
kVA* 0.5  (( NL  LL * 0.91* 0.52 ) / 1000)
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
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Efficiency Calculations
No Load Loss Impact
25 kVA 1 Phase Designs having the same Total Losses
at 100% Load / 85°C
99.20
Efficiency @ 100% Load / 85°C
Efficiency @ 50% Load / 55°C
NL/LL=
0.182
99.10
DOE Minimum Efficiency
Tr ansformer Efficiency (%)
99.00
98.91%
98.90
98.80
100 * kVA* 0.5
% EFF 
kVA* 0.5  (( NL  LL * 0.91* 0.52 ) / 1000)
98.70
98.60
98.50
98.44%
98.40
98.30
98.20
98.10
98.00
0
0.2
0.4
0.6
0.8
1
1.2
NL / LL Ratio (85°C)
%EFF  100 x kVA x 0.5/[kVA x 0.5  ((NL  LL x 0.91 x 0.52 )/1000)]
No Load Losses represent a critical portion of the
Transformer Efficiency
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Efficiency Calculations
Examples 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)
% EFF 
100 * 25 * 0.5
25 * 0.5  ((75  325 * 0.91* 0.52 ) / 1000)
%EFF  98.82%
Does Not Meet DOE Rule of 98.91%
• Design #2: NL=55W, LL=345W, TL=400W (NL/LL=0.16)
100 * 25 * 0.5
% EFF 
25 * 0.5  ((55  345 * 0.91* 0.52 ) / 1000)
%EFF  98.94%
Meets DOE Rule of 98.91%
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Efficiency Calculations
Load Loss Impact
99.50
25 kVA Single Phase Designs
Effic @100% & 85°C
Effic. @ 50% & 55 °C
99.30
DOE
99.10
Efficiency
98.90
98.70
98.50
98.30
98.10
97.90
97.70
97.50
Load Losses
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Efficiency Calculations
Efficiency vs Losses
Loss Differential for 0.01 Percent Change in Efficiency
Single Phase 10 to 833 kVA
and Three Phase 15 to 2500 kVA
% Reduction of Losses needed for 0.01 increment in
Efficiency
2.5
2
1.5
1
Delta (%) 1Ph
Delta (%) 3Ph
0.5
0
98.00
98.20
98.40
98.60
98.80
Efficiency
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99.00
99.20
99.40
99.60
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Efficiency Calculations
Percent of available designs that
meet DOE Rule
60
50
Percent
40
30
20
10
0
10
15
25
37.5
50
75
100
167
kVA Rating
Around 50% of present designs available already meet the
Efficiency Levels of the DOE Rule
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Impact on Materials
Core 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
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Impact on Materials
Published Typical Losses of different Core Materials
At 1.5 Tesla / 60 Hz, (except for SA1 which is at 1.3 Tesla)
1.4
1.2
“M3 or Better” Grade
Required to Meet
DOE
M6, 14 mil
1.27
M5 12 mil
M4, 11 mil
1
Losses (W/kg)
M3, 9 mil
M2, 7 mil
1.09
1.00
M0H, 9 mil
0.8
0.89
0.84
0.82
0.6
0.4
SA1
(Amorphous)
1 mil
0.30
0.2
0
1
Core Material
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Impact on Materials
2007 World Installed Production of Grain Oriented Silicon Steel*
EBG/India
0%
Viz Stal
Russia
17%
East Europe
2%
NIPPON STEEL
Japan
13%
JFE
Japan
9%
Acesita
Brazil
2%
POSCO
S.Korea
12%
Allegheny
USA
4%
AK Steel
USA
15%
Wuhan/China
13%
Cogent/W. Eur.
4%
TKES/W. Eur.
12%
Total = 2.1 Million (MT)
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* Data Courtesy of
Sumitomo Corporation
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Impact on Materials
2007 World Installed Production of Hi B Silicon Steel*
Posco
S. Korea
23%
Nippon SC
Japan
32%
COGENT
W. Eur.
1%
AK Steel
USA
8%
JFE
Japan
19%
TKES/ W. Eur.
17%
Total = 0.64 Million (MT)
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* Data Courtesy of
Sumitomo Corporation
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Impact on Materials
World Installed Capacity of Grain Oriented Silicon Steel*
Acesita
(Thousands of MT)
40
2500
Alsco
90
AKS
Russia
320
Other European
2000
40
TKES
90
Baoshang
30
Wuhan
1500
380
304
80
Posco
30
Japan
80
30
80
114
270
330
230
330
230
111
250
160
310
111
1000
110
100
240
250
250
75
120
400
400
400
2004
2005
2006
13
400
200
0
130
0
60
40
200
0
230
500
250
310
410
250
440
0
Year 2007
13
75%+ of
Growth in
Capacity in
Asia; intended
for domestic
market
* Data Courtesy of
Sumitomo Corporation
Proj 2008
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Impact on Manufacturers
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
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Impact on Manufacturers
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
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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
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Impact on Customers
DOE Impact on Designs Quoted
• 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>$1.50):
 Typical current offerings meet or exceed DOE minimum efficiencies
%EFF  100 x kVA x 0.5/[kVA x 0.5  ((NL  LL x 0.91 x 0.52 )/1000)]
Equivalent A & B factors will be driven by NL/LL ratio to meet
DOE Min. Efficiency
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Customer Purchasing Practices
Current Purchasing Practices:
• Non-Evaluated
 Decision based on Lowest Price meeting ANSI/IEEE Standards
 Leads to Low Efficiencies
• Total Owning Cost (TOC) Loss Evaluation
 TOC = (NL × A) + (LL × B) + Price
where:
o TOC = total owning cost ($),
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
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Customer Purchasing Practices
TOC and Band of Equivalence (BoE) Concepts
$
Cost of Losses
Transformer Cost
Total Owning Cost
3% BoE
A higher TOC
due to a 3% BoE,
leads us to a ...
Lowest TOC
Design
... lower First Cost
Transformer,
roughly 4-6%
$
$
~4 - 6 % lower First Cost
Total Losses
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Customer Purchasing Practices
Purchasing Practices in a DOE Rule environment:
• For Non-Evaluated Segment:
 DOE Min. Efficiency will result in lower loss designs
 Purchase 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 design
 Purchase 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 units
 Customers may choose to continue with TOC evaluations
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Outstanding Issues / Concerns
• 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
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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
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Thank You!
Carlos Gaytan
Manager of Engineering
Distribution Transformers
Email: [email protected]
April 29, 2008
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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
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