Development & Tec

SQUARE D MONROE ELECTRICAL SYSTEM

Duke (2) 2000 kVA 1000 kVA 75kV

A

Stage 1 Stage 2 Stage 3

Duke

Energy

24940V 4160V

MV Liquid Filled

24940: 4160GrdY / 2400 V 4160: 480GrdY / 277 V

MV Dry

480V

LV Dry Offi

ComandPerip

24940: 4160GrdY / 2400

V 4160: 480GrdY / 277

V 480: 208GrdY / 120V 480: 208GrdY / 120V

Other MV Dry Transformers Other LV Dry Transformers

Figure 1
Development & Tec

Monroe Plant Typical Load Cycle

0 50.60.70.8

ad

RMS Load Actual PU Load 

0.10.20.30.40.5

PU Loa

Friday Saturday Sunday Monday Tuesday Wednesday Thur

0

0.1

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00 PM

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Time & Day
Development & Tec

Figure 3: 1000 kVA Substation 4 Power Quality Readings 

Schne·der 

Electric 

Time: 11 :29:39 

Date: 8/23/2000 
Development & Tec

Table1: Substation4PowerQualityAnalysis 8 23 2000

Harmonic Current In rms amperes Current,% of TotalFundamental 102.42 99.951

2 0.28 0.2

7

3

3 1.34 1.3

0

8

Table

1: Substation

4PowerQualityAnalysis-8-23-2000

4 0.07 0.0

6

8

5 2.21 2.15

7

6 0.07 0.0

6

8

7 0.56 0.5

4

7

8 0.06 0.0

5

9

9 0 1. 5 0 146 .

10 0.08 0.078

11 0.11 0.10712 0.09 0.08813 0.2 0.195

14 0 05 . 0 049 .15 0.06 0.059

16 0.04 0.03917 0.09 0.08818 0.05 0.049

19 0.1 0.09820 0.07 0.068

21 0.06 0.05922 0.02 0.02023 0.06 0.05924 0.08 0.078

Total rms amps 102.47
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Figure 4: Substation 4 Instantaneous Voltage and Current Traces on 4160 V

Primar

y
Development & Tec

Figure 5 Figure

5: Power Quality Readings on Lighting Panel 32 @ 480 V Power Quality Readings on Lighting Panel 32

@ 480

V

Power Quality Readings 

Device: LP 32 

Time: 11 :30:22 

Date: 8/23/2000 

Phase A 

Phase B 

Phase C 

3-Phase Total 

3.4 

2.9 2.2 

N/A 

I 1 1 1 

1.26 

5.6 

1 6.3 

0.3 1.3 5.4 0.3 1.1 5.7 0.3 0.9 5.6 0.4 

.•.• ••..•• •. .•.......•. ••..•••. •.•.. .... ••... 

-1 • 0 .•. 0 -1 .... . 0 . 2 -2 0 ..... 3 
Development & Tec

Figure 6: Lighting Panel 32 Instantaneous Voltage and Current T
Development & Tec

Fi 7gure 

7a: I V nstantaneous 

V

ol d ta

ge an

d C LV urrent on 

Low 

V

ol 7 ta

ge 75

kVA

Dr

y Type Secondar

y at 11:17 a.m. on 10/4/00

Ph A N Ph A

-

-53

0

53

105

17 33 50 

Phase 

A

-

-84

0

84

168

17 33 50 66

Phase 

A-N

-24

0

2448

17 33 50 

Phase B

-83

0

83

166

17 33 50 66

Phase B-N

3467

Phase C

-48-24

83

167

Phase C-N

-

-83

-67-34

0

17 33 50 

-

-83

0

17 33 50 66
Development & Tec

Figure 7b: Instantaneous Voltage and Current on Low Voltage 75 kVA

Dr

y Type Secondar

y at 12:00 

p.m. on 10/4/00

-

0

5

10

135

Phase A

-

0

8

16

1356

Phase A-N

0

36

1 3 5 

Phase B

-

0

8

16

1 3 5 6Phase B-N

-

37

Phase C

-- 1 3 5 

8

16

Phase C-N

-

- 1 3 5 6

--

0

3

135

-

-

0

8

1356
Development & Tec

T bl 2 I C H i f 11 17 10/4/00

Square D Monroe Low Voltage Transformer Office Load Analysis on 208Y/120V Output of 75 kVA T3H Tran

by PJ Hopkinson 10/4/00

Ia= 44.09 Ib= 19.66 Ic= 26.87

A t 31 90 E l 15 31 %L d

Phase A Phase B Phase C

T

able 

2: Instant 

Current 

Harmonics from 11:17 a.m. on 10/4/00

Average rms current, amps 31.90

Equals 15.31

%

Loa

d

h Ih Ih(pu) h^2*(Ih(pu))

^ h Ih Ih(pu) h^2*(Ih(pu))

^ h Ih Ih

1.00 34.51 0.78 0.61 1.00 16.86 0.86 0.74 1.00 20.66 02.00 0.03 0.00 0.00 2.00 0.09 0.00 0.00 2.00 0.14 03.00 23.30 0.53 2.51 3.00 7.11 0.36 1.18 3.00 13.75 04.00 0.15 0.00 0.00 4.00 0.06 0.00 0.00 4.00 0.14 05.00 13.40 0.30 2.31 5.00 5.87 0.30 2.23 5.00 9.10 06.00 0.14 0.00 0.00 6.00 0.01 0.00 0.00 6.00 0.21 07.00 4.67 0.11 0.55 7.00 3.50 0.18 1.55 7.00 4.33 08.00 0.04 0.00 0.00 8.00 0.06 0.00 0.00 8.00 0.08 09.00 1.43 0.03 0.09 9.00 1.85 0.09 0.72 9.00 1.29 0

10.00 0.03 0.00 0.00 10.00 0.05 0.00 0.00 10.00 0.06 011.00 1.98 0.04 0.24 11.00 0.56 0.03 0.10 11.00 0.90 0

12 00 . 0 15 . 0 00 . 0 00 . 12 00 . 0 03 . 0 00 . 0 00 . 12 00 . 0 006 . 0 13.00 1.03 0.02 0.09 13.00 0.48 0.02 0.10 13.00 0.95 014.00 0.04 0.00 0.00 14.00 0.06 0.00 0.00 14.00 0.04 015.00 0.55 0.01 0.04 15.00 0.52 0.03 0.16 15.00 0.56 016.00 0.12 0.00 0.00 16.00 0.01 0.00 0.00 16.00 0.03 017.00 0.44 0.01 0.03 17.00 0.35 0.02 0.09 17.00 0.50 018.00 0.01 0.00 0.00 18.00 0.05 0.00 0.00 18.00 0.02 019.00 0.21 0.00 0.01 19.00 0.29 0.01 0.08 19.00 0.43 020.00 0.05 0.00 0.00 20.00 0.01 0.00 0.00 20.00 0.10 021.00 0.33 0.01 0.02 21.00 0.31 0.02 0.11 21.00 0.36 022.00 0.01 0.00 0.00 22.00 0.02 0.00 0.00 22.00 0.03 023.00 0.24 0.01 0.02 23.00 0.29 0.01 0.12 23.00 0.12 024.00 0.18 0.00 0.01 24.00 0.06 0.00 0.01 24.00 0.05 0

K= 6.53 K= 7.17 

Average K factor = 7.24
Development & Tec

Square D Monroe Low Voltage Transformer Losses Square D Monroe Low Voltage Transformer Losses By PJ Hopkinson By PJ Hopkinson

10/05/2000

Objective: Determine losses in Low Voltage Transformer supplying office load Approach: 1. Load profile as measured using Power Logic Sensor at Square D Monroe Office 2. Installed transformer (75kVA standard T3H) from 1983, with losses calculated using IEEE C57.1 3. Recalculated transformer losses in 75kVA T3H(EE), meeting NEMA TP-1 1996 Efficiency

Load Summary: 1. RMS Average Load Current 31.9 amperes = 15.3% of rated 208.3 amperes rated current 2. Average K factor = 7.24 on 208GrdY/120 V Load side of transformer with total harmonic distor 3. Voltage harmonics less than 2% total Harmonic distortion and are ignored.Item 75 kVA T3H 75 kVA T3H (EE)

Losses %

No-load loss 432 253 179 

Improvemen

No-load loss 432 253 179 Full Load Load Loss @75C (K=1)a. Primary 1249 1019 230 b. Secondary 782 707 75 c. Total Load Loss 2031 1726 305 Eddy Current losses @75C (K=1)a. Primary 31 24 7 

b. Secondary 65 35 30 

Eddy Current losses @75C (K=7.24)

a. P ir mary 224 4. 173 8. 50 68 . b. Secondary 470.6 253.4 217.2 

Full Load Load Loss @75C (K=7.24)a. Primary 1442.4 1168.8 273.68 b. Secondary 1187.6 925.4 262.2 Load Loss @ 15.3% Load, K=7.24a. Primary 33.8 27.4 6.4 

b. Secondary 27.8 21.7 6.1 c. Total Load Loss 61.6 49.0 12.5 

Total Loss (Load + No Load)@15.3% Load, K=7.24 493.6 302.0 191.5 

%Efficiency @ 15.3% Load, K=7.24 95.88 97.44Average Winding Temperature Rise, degrees C 19 16

Total Loss ( Load + No Load)@15.3% Load, K=1 479.5 293.4 186.1 %Efficiency@15.3%Load, K=1 95.99 97.51

Total Loss (Load + No Load)@35%Load, K=1 680.8 464.4 216.4 %Efficiency@35%Load, K=1 97.47 98.26

754 2 509 5

Total Loss (Load + No Load)@35%Load, K=7.24 754.2 509.5 244.6 

%Efficiency@35%Load, K=7.24 97.21 98.10