Eff vs Load

98.6%

98.8%

99.0%

99.2%

99.4%

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 T3 %Efficency T4 %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 T3 losses T4 losses
Design

$1,575 

$2,444 

$2,655 

$2,800 

$1,300 

$1,800 

$2,300 

$2,800 

$3,300 

99.0%

99.0%

99.1%

99.1%

99.2%

99.2%

99.3%

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 

98.8%

98.9%

98.9%

99.0%

Present 2010 design M3_CuAl_dgw_sh M2_CuAl_dgw_sh ZDMH_CuCu_dgw_sh

T1 T2 T3 T4
50 kVA Single-phase pad-mount transformer

13200 to 240/120

125 kV BIL

Ratio "A"/"B" 5.3 4.6

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

4.6 3.8

C03_F3_A11.00_B3.33 D01_C05_G3_A16.00_B3.50 D01_C07_G3_A16.00_B4.50

uAl_dgw_sh M2_CuAl_dgw_sh ZDMH_CuCu_dgw_sh

$2,655 $2,800

$915 $882

$/watt watts/kVA $3,570 $/watt watts/kVA $3,682 $/watt watts/kVA

$4.00 2.00 92.44 $4.00 1.85 99.98 $4.00 2.00

$1.27 9.13 429.12 $1.27 8.58 379.78 $1.27 7.60

521.56 479.76

99.21% 99.23%

0.46 0.51

T2 T3 T4

losses T2 losses T3 losses T4

@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% 522 190 98.97% 480 175 99.05%

401 98.91% 507 376 98.98% 467 346 99.06%

597 98.91% 504 559 98.98% 464 515 99.06%

766 98.97% 433 717 99.04% 401 661 99.11%

929 98.98% 419 870 99.05% 389 803 99.12%

1089 98.99% 410 1020 99.06% 381 943 99.12%

1245 99.00% 400 1166 99.06% 372 1078 99.13%

1399 99.00% 396 1310 99.07% 368 1213 99.13%

1528 99.06% 329 1430 99.12% 309 1326 99.17%

1640 99.09% 289 1536 99.15% 274 1426 99.20%

1750 99.10% 279 1638 99.16% 265 1522 99.20%

1856 99.11% 274 1738 99.16% 260 1617 99.21%

1961 99.11% 267 1835 99.17% 255 1710 99.21%

2062 99.12% 258 1929 99.18% 247 1800 99.21%

2161 99.12% 256 2023 99.18% 244 1889 99.21%

2260 99.12% 252 2115 99.18% 241 1978 99.22%

2356 99.13% 245 2204 99.18% 235 2063 99.22%

2452 99.13% 245 2294 99.18% 235 2149 99.22%

2547 99.13% 244 2383 99.19% 234 2235 99.22%

2642 99.13% 242 2471 99.19% 233 2320 99.22%

2736 99.13% 242 2559 99.19% 232 2404 99.22%

2829 99.13% 237 2646 99.19% 228 2487 99.22%

2919 99.14% 229 2729 99.19% 221 2568 99.22%

3007 99.14% 226 2812 99.20% 218 2648 99.22%

Efficiency overall - 99.05% Efficiency overall - 99.11% Efficiency overall - 99.16%

$1,080 $1,225

537 701
$35 $46

31 27

32 28
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

T3 T4

M2_CuAl_dgw_sh ZDMH_CuCu_dgw_sh

99.21% 99.23%

99.13% 99.18%

$2,655 $2,800

rly demands.