IIEE Load Calculation and Voltage Drop Presentation

 

Load Calculation and Voltage Drop Calculation

 

Load Calculation Fundamental Principles PEC

 

PEC 1.3.2.1 (f)

 

Branch Circuit Generally for the branch circuit, PEC 2.10 can be used as guide. The circuit’s   rating is based on the ampacity of the cable or the Over Current Protective Device (OCPD) rating as rega re gard rded ed in PEC 2. 2.10 10.1 .1.3 .3.. As a fun unda dame ment ntal al gu guid ide, e, PE PEC C 2.10.2.1 (a) suggests that the ampacity should be based on 100% non-continuous loads plus 125% of continuous loads.

 

8 28 b 24 8 16 16 24 4 16 16

16 12 28 b 16 24 24 2

8 4 2

 

Feeder Protection Protection + FLC of Other Protection = Highest Motor Protection

 

Voltage Drop Calculation

 

Voltage Drop (Using Per Unit Calculation) Establishment of Single Line Diagram withCalculations Per Unit (pu) Impedance

 

Single Line Diagram

To be discussed in Sample Computation

 

1 pu

1 pu Genset Cable ZG1  =

Tie Connection

ZG2  =

ZUM  =

ZUK =

ZUM-A1 =

ZUK-A2 =

ZA1  =

ZA2  =

ZA1-M1 =

ZA2-M2 =

Tie Connection Z

 =

G1-S

ZS-L1  =

Z

 =

G2-S

ZS-L3 =

ZS-L2 =

ZS-L4  =

ZM1-F1 =

MVSG1

MVSG2

CB

CB

ZM1-F3 =

ZM2-F2 =

ZM2-F4 =

Feeder1

Feeder3

Feeder2

Feeder4

CB

CB

CB

CB

ZF1-T1 =

ZF3-T3 =

ZF2-T2 =

ZT1  =

ZT3  =

ZT2  =

ZT4  =

ZT1-L1 =

ZT3-L3  =

ZT2-L2 =

ZT4-L4  =

LVSG1 CB ZL1  =

LVSG3 CB ZL3  =

ZF4-T4 =

LVSG2

LVSG4

CB

CB

ZL2  =

ZL4  =

 

Sample for Marikina 1 pu

ZUM =

ZUM-A1 =

ZA1 =

ZA1-M1 =

MVSG1 CB

ZM1-F1 =

ZM1-F3 =

Feeder1

Feeder3

CB

CB

ZF1-T1 =

ZF3-T3 =

ZT1 =

ZT3 =

ZT1-L1 =

ZT3-L3 =

LVSG1 CB ZL1 =

LVSG3 CB ZL3 =

 

Sample Per Unit (pu) Impedances Calculations Impedances

Base Values

LV

HV

1 Utility

SB

400000 0

40000 00

2 Cable

VB

48 0

345 00

3 Transformer & AVR

ZB =

0.0576

297.5625

Solved Bases

4811.25

66.93916

Solved Bases

4 Bus Duct

VB2

Chosen Bases

SB

5 Load

IB =

SB √3 x VB

Utility SF =

Marikina SB

Zpu =

Zpu Zpu =

SB SF

Kamuning SB

Zpu =

SF Zpu =

400000 0

From Meralco 3.2E+0 8

SB SF

Zpu =

4000000

From Meralco 2.86E+08

Zpu =

0.01262

Zpu =

0.013986

 

R

L

Ω  /km

H/km

60mm2

 

100mm2

0. 247

Ω  /km

 

0. 342

From Table

Z

ω

From Table

Ω  /km

 

0.000482

0.1817097

0. 38728

0.000458

0.1726619

0. 30137

Cable 100mm2, Utility to AVR Zactual =

Z per km x

1 km / 1000 m

length in m

# of sets Zactual =

0.3013655 1

Zactual = Zpu =

0.0150683 Zactual ZB

Zpu =

0.0150683 297.5625

0.001

50

Estimated at Site

Zpu =

5.064E-05

 

Bus Duct

Zpu =

Zactual

ZB Zactual =

10-3 ohm per mili oh ohm x

Z mili o oh hm per 100m x

Zactual =

From Table1.8

Zactual =

0.000036

Zpu =

0.000036

1 / 100 x

0. 001

0.0576

Zpu =

0.0003125

0.000625

length in m

0.01

2

Estimated at Site

 

Transformer

Zpu(new) =

Zpu(old) x

SB(new)

SB(old) Zpu(new) =

0. 062 From Nameplate

40000 00

4000000

Zpu(new) =

0.062

 

AVR (Autotransformer) Conversion from Two-winding to Autotransformer For Step-Up Auto Zpu(auto) =

Zpu(two-wind) a+1

a=

Zpu(auto) =

10

From Nameplate

0.06

From Nameplate

Zpu(two-wind) a+1

Zpu(auto) =

11 Zpu(auto) =

S(auto) =

0.0054545

S(two-wind) x

a+1 10000 00

S(auto) = Zpu(new) =

11

11000000 Zpu(old) x

SB(new) SB(old)

Zpu(new) =

0.0054545

40000 00 11000000

Zpu(new) =

0.0019835

 

Load (LVSG) Zpu =

Zactual ZB

Zactual =

Vphase Iphase

Zactual =

277.12813 2400 From Client’s Load

Data

Zactual =

0.1154701

Zpu =

0.1154701 0.0576

Zpu =

2.0046884

 

Table 3.2.1-2 Summary of Impedances For Kamu Ka munin ning g Cir Circui cuitt

Table 3.2.1-1 Summary of Impedances For Marikina Circuit 1 ZUM 2 ZUM-A1

0.012618297 5.0639E-05

1 ZUK 2 ZUK-A2

0.013986014 5.0639E-05

3 ZA1

0.001983471

3 ZA2

0.001983471

4 ZA1-M1

1.01278E-05

4 ZA2-M2

1.01278E-05

5 ZM1-F1

1.04119E-05

5 ZM2-F2

1.04119E-05

6 ZM1-F3

2.08239E-05

6 ZM2-F4

2.08239E-05

7 ZF1-T1

5.20597E-06

7 ZF2-T2

5.20597E-06

5.20597E-06

8 ZF4-T4

5.20597E-06

8 ZF3-T3 9 ZT1

0.062

9 ZT2

0.062

10 ZT3

0.062

10 ZT4

0.062

11 ZT1-L1

0.0003125

11 ZT2-L2

0.0003125

12 ZT3-L3

0.0003125

12 ZT4-L4

0.0003125

13 ZL1

2.004688435

13 ZL2

2.004688435

14 ZL3

2.004688435

14 ZL4

2.004688435

 

Table ble 3. 3.2. 2.11-3 3 Sum umma mary ry of Im Impe peda danc nce es Forr Em Fo Emer erge genc ncy y Circ Circui uitt

1 ZG1

0.16512

2 ZG2

0.16512

3 ZG1-S

0.003283943

4 ZG2-S

0.003283943

5 ZS-L1

0.004269126

6 ZS-L2

0.004269126

7 ZS-L3

0.007115209

8 ZS-L4

0.007115209

 

Fig 3.2.1-1 3.2.1-1 Over Overall all Im Impeda pedance nce Diagram for Voltage Drop 1 pu

ZUM =

ZT

ZS3

ZUM-A1 =

ZA1 =

ZA1-M1  =

IT MVSG1 CB

ZM1-F1 =

ZM1-F3 =

Feeder1

Feeder3

CB

CB

ZF1-T1 =

ZS1

ZS2

ZT1 =

ZT3 =

ZT1-L1  =

ZT3-L3 =

LVSG1

LVSG3

CB ZL1 =

ZP

ZF3-T3 =

CB

I1

ZL3 =

I2

 

ZS1 =

ZM1-F1

ZF1-T1

=

1.0412E-05

=

2.06701655

ZS2 =

ZM1-F3

5.21E-06

ZF3-T3

=

2.0824E-05

=

2.06702696

ZS3 =

ZT1

ZUM 0.0126183

=

0.01466253

5.21E-06

5.06E-05

ZS1

ZS2

ZS1 + ZP =

ZP =

ZS2 2.067

2.06702696

2.067

2.06702696

1.034

ZT = =

ZP

ZS3 1.03351088

0. 014663

ZL1 0. 00031

ZT3-L3 0.062

ZA1

PARALLEL ZP =

0.062

ZT3

ZUM-A1

=

ZT1-L1

ZL3 0. 00031

ZA1-M1 0.00198

2. 00469

1E-05

2. 00469

=

1.04817341

 

IT =

1 ZT

IT =

1 1.04817341

IT =

0.95404061

By Current Divider Rule I1 =

IT

ZS2

ZS1 +

ZS2

I1 =

0.954

2.06702696

I1 =

2.067 0.477

2.06702696

V

pu VL1 =

I1

ZL1

=

0. 4770215

= V

0.95627949 pu

actual VL1 =

%VD

2. 004688

V pu

V base

=

0.95627949

=

459.014157

=

1-

480

V pu

x 100%

=

1

0. 956279 x 100%

=

4.37%

 

Summary From

To

V pu

V base

V actual

% VD

Utility

MVSG1

9.827E-01

34500

33903.15

1.730%

Utility

MVSG F1

9.827E-01

34500

33903.15

1.730%

Utility

MVSG F3

9.827E-01

34500

33903.15

1.730%

Utility

LVSG 1

9.531E-01

480

457.488

4.690%

Utility

LVSG 3

9.530E-01

480

457.44

4.700%

From

To

V pu

V base

V actual

% VD

Utility

MVSG2

9.814E-01

34500

33858.3

1.860%

Utility

MVSG F2

9.814E-01

34500

33858.3

1.860%

Utility

MVSG F4

9.814E-01

34500

33858.3

1.860%

Utility

LVSG 2

9.518E-01

480

456.864

4.820%

Utility

LVSG 4

9.518E-01

480

456.864

4.820%

 

Thank you!

Engr. Mark Christian P. Plaza, PEE MCPP MUL MULTIDISCIPLINE TIDISCIPLINE CONSTRUCTION AND PROJECT PROFICIENCY “Managers

Consultants Professional Partners”