Figure 54: Distribution Of Currents During A Phase C Fault; Figure 55: Phasors For A Phase C Earth Fault In A Petersen Coil Earthed System - GE MiCOM P40 Agile Technical Manual

Chapter 6 - Current Protection Functions
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Figure 54: Distribution of currents during a Phase C fault

Assuming that no resistance is present in X
below:
I
H3
I A
L
I
H2
I
H1
I
B1
I
A1
N
C
a) Capacitive and inductive currents
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Figure 55: Phasors for a phase C earth fault in a Petersen Coil earthed system

126
I
L
jX
L
I = I + I + I + I
L F H1 H2
or X , the resulting phasor diagrams will be as shown in the figure
L C
3V
0
B
I
A1
I
B1
I
R1
-jX
C1
I
H1
I
A2
I
B2
I
R2
-jX
C2
I
H 2
I
A3
I
B3
I = I
C3 F
I
R3
-jX
C3
I
F
I
I + I
H3
H1 H2
H3
I = I
R1 H1
I
b1
I
a1
V = -3V
res o
b) Unfaulted line
P14x
I
L
-I
H1
-I
H2
I I = I + I
R3 R3 F H3
= I - I
L H1
V = -3V
res o
c) Faulted line
P14xEd1-TM-EN-1
- I
H2