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POWER SYSTEM ANALYSIS
TADP 641
Case Example
SHORT CIRCUIT
CALCULATION
Juan Manuel Gers, PhD
Example
Example
Calculate the short circuit current for a three phase fault at busbar D.
Consider that the Hydro Power Station is under maintenance and therefore all the breakers associated are open.
Let base MVA = 75 MVA
Let base kV on 132 kV nominal part of system = 132 kV
The base kV on other parts of the system is obtained by referring this voltage through the interconnecting transformers.
Example Solution
SUPPLYGRID
G3
G4
G5
G6
E'
T9
T10
T17
T18
T16
T15
E
D6
T20
T21
T13T11
D4B
D4A
T12
F'
F
D5
DT7
T8
D'
D2
C C'
Positive Secuence Diagram for Fault at Busbar D
NEUTRAL BUS ' N '
E
G6
G5
G4
G3
T18
T17
T16
T15
FI
F
D5
D4B
D4A
D6
E
T10
T9
E'
SZ
D
Positive Sequence Network
P.U.1E
FI
EE'
Z
F
E
I
AZ
D
ZB
FI
E
A
D
ZC
Equivalent Impedances
The resulting positive sequence diagram is shown below:
..0712.04
285.0
4
151.0134.0upZ A
..0897.00327.0047.001.01768.0
1335.00433.0
2
094.001.0 up
xZ B
..0397.01607.0
0897.00712.0upZC
..19.250397.0
1up
Z
EI
c
F
Axx
xupcurrentBase 328
101323
1075.).1(
3
6
Fault Current Calculation
Solution of Example with Software
Questions?
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