Eff vs Load

98.8%

99.0%

99.2%

99.4%

99.6%

Efficie

n

c

y

25 kVA Single-phase Pole Type

Page 1

98.2%

98.4%

98.6%

1.00 0.98 0.98 0.89 0.87 0.86 0.85 0.84 0.74 0.68 0.66 0.65 0.64 0.62 0.62 0.61 0.60 0.60 0.59 0.59 0.59 0.58 0.56 0.56

Transformer Load (p.u.)

T1 %Efficency T2 %Efficency T5 %Efficency T6 %Efficency
1500 

2000 

2500 

3000 

3500 

4000 

kilo

w

att-h

o

urs (k

W

h)

25 kVA Single-phase Pole Type

0 

500 

1000 

Equivalent Hours

T1 losses T2 losses T5 losses T6 losses
Design

$1,575 

$2,444 

$3,069 

$3,415 

$1,800 

$2,300 

$2,800 

$3,300 

$3,800 

99.0%

99.1%

99.2%

99.3%

99.4%

99.5%

99.6%

Initial C

o

st (I.C.)

Efficie

n

c

y

Equivalent (p.u.) 0.73 Equivalent (p.u.) 0.5 I.C.

Page 1

$300 

$800 

$1,300 

98.6%

98.7%

98.8%

98.9%

Present 2010 design M3_CuAl_dgw_sh SA1_AlAl_dgw_sh SA1_CuCu_dgw_sh

T1 T2 T5 T6
50 kVA Single-phase pad-mount transformer

13200 to 240/120

125 kV BIL

Ratio "A"/"B" 5.3 4.6

64% D01_C03_F3_A11.00_B3.33

Present 2010 design M3_CuAl_dgw_sh

I.C. $1,575 $2,444

Loss Cost $1,073 $980

E.C. $2,648 $/watt watts/kVA $3,424

Pnl "A-factor" 100 $4.00 2.00 100

Pll "B-factor" 530 $1.27 10.60 456.71

Ptotal 630 556.71

Max eff 99.09% 99.15%

@ p.u. 0.43 0.47

p.f.

1.00 T1

losses T1

LOAD LOAD Ptotal @pu load %Efficency Ptotal

Hours (kWH) (p.u.) @ p.u. load (kWH) @p.u. load @ p.u. load

365 18,250 1.00 630 230 98.76% 557

730 36,195 0.98 612 453 98.77% 542

1095 54,060 0.98 608 675 98.77% 538

1460 70,317 0.89 521 865 98.84% 462

1825 86,236 0.87 503 1049 98.86% 448

2190 101,937 0.86 492 1229 98.87% 438

2555 117,389 0.85 480 1404 98.88% 427

2920 132,730 0.84 475 1577 98.88% 423

3285 146,273 0.74 392 1720 98.95% 352

3650 158,612 0.68 342 1845 99.00% 309

4015 170,656 0.66 331 1966 99.01% 299

4380 182,515 0.65 324 2084 99.01% 293

4745 194,158 0.64 316 2199 99.02% 286

5110 205,496 0.62 305 2310 99.03% 276

5475 216,747 0.62 301 2420 99.03% 274

5840 227,882 0.61 297 2529 99.03% 270

6205 238,775 0.60 289 2634 99.04% 263

6570 249,664 0.60 289 2740 99.04% 263

6935 260,502 0.59 287 2844 99.04% 261

7300 271,288 0.59 285 2949 99.04% 260

7665 282,058 0.59 285 3052 99.04% 259

8030 292,643 0.58 278 3154 99.05% 254

8395 302,950 0.56 269 3252 99.06% 246

8760 313,130 0.56 265 3349 99.06% 242

 Efficiency overall - 98.94% Efficiency overall -

$20,604 Energy cost

OC1Y2009 Cost adder $869

$0.0658 saved kWh 342
per kWh Saved per yr $23

Pay back yrs 39

Pay back yrs at 4.00% 40
transformer

7.7 7.9

C03_F3_A11.00_B3.33 D01_C08_G3_A16.00_B7.50 D01_C09_F3_A16.00_B4.84

uAl_dgw_sh SA1_AlAl_dgw_sh SA1_CuCu_dgw_sh

$3,069 $3,415

$768 $574

$/watt watts/kVA $3,837 $/watt watts/kVA $3,988 $/watt watts/kVA

$4.00 2.00 55.65 $4.00 1.11 40.75 $4.00 0.82

$1.27 9.13 429.12 $1.27 8.58 323.39 $1.27 6.47

272.19 364.14

99.39% 99.54%

0.36 0.35

T2 T5 T6

losses T2 losses T5 losses T6

@pu load %Efficency Ptotal @pu load %Efficency Ptotal @pu load %Efficency

(kWH) @p.u. load @ p.u. load (kWH) @p.u. load @ p.u. load (kWH) @p.u. load

203 98.90% 485 177 99.04% 364 133 99.28%

401 98.91% 471 349 99.05% 353 262 99.29%

597 98.91% 467 519 99.06% 351 390 99.29%

766 98.97% 396 664 99.12% 297 498 99.34%

929 98.98% 382 803 99.13% 287 603 99.35%

1089 98.99% 373 939 99.14% 280 705 99.35%

1245 99.00% 363 1072 99.15% 273 805 99.36%

1399 99.00% 359 1203 99.15% 269 903 99.36%

1528 99.06% 292 1310 99.22% 219 983 99.41%

1640 99.09% 252 1401 99.26% 189 1052 99.45%

1750 99.10% 243 1490 99.27% 182 1118 99.45%

1856 99.11% 237 1576 99.28% 177 1183 99.46%

1961 99.11% 230 1661 99.28% 172 1246 99.46%

2062 99.12% 221 1741 99.29% 166 1306 99.47%

2161 99.12% 219 1821 99.30% 164 1366 99.47%

2260 99.12% 215 1900 99.30% 161 1425 99.47%

2356 99.13% 209 1976 99.31% 156 1482 99.48%

2452 99.13% 208 2052 99.31% 156 1539 99.48%

2547 99.13% 207 2127 99.31% 155 1595 99.48%

2642 99.13% 206 2203 99.31% 154 1651 99.48%

2736 99.13% 205 2277 99.31% 153 1707 99.48%

2829 99.13% 200 2350 99.32% 150 1762 99.49%

2919 99.14% 193 2421 99.32% 144 1814 99.49%

3007 99.14% 189 2490 99.33% 141 1866 99.50%

Efficiency overall - 99.05% Efficiency overall - 99.21% Efficiency overall - 99.41%

$1,494 $1,840

859 1483
$57 $98

26 19

28 20
Load T1 T2

(p.u.) Present 2010 design M3_CuAl_dgw_sh

Equivalent (p.u.) 0.5 99.08% 99.15%

Equivalent (p.u.) 0.73 98.96% 99.07%

I.C. $1,575 $2,444

Note: System load curve taken from year 2005 hourly demands.

1 365

0.967 352.907

0.958 349.746

0.794 289.633

0.761 277.724

0.740 270.164

0.717 261.659

0.707 257.923

0.551 201.002

0.457 166.847

0.436 158.959

0.422 154.117

0.407 148.552

0.386 140.891

0.380 138.725

0.372 135.876

0.356 130.031

0.356 129.954

0.353 128.707

0.349 127.508

0.348 127.098

0.336 122.788

0.319 116.431

0.311 113.578

0.73

(rms value)

Equivalent load

T5 T6

SA1_AlAl_dgw_sh SA1_CuCu_dgw_sh

99.35% 99.52%

99.23% 99.42%

$3,069 $3,415

rly demands.