impedance and negative-sequence impedance are the same and that the influences of the fault
resistance are ignored.
where,
V
:
Relay point positive-sequence voltage
1
V
:
Relay point negative-sequence voltage
2
V
:
Relay point zero-sequence voltage
0
V
F:
Fault point positive-sequence voltage
1
V
F:
Fault point negative-sequence voltage
2
V
F:
Fault point zero-sequence voltage
0
I
:
Relay point positive-sequence current
1
I
:
Relay point negative-sequence current
2
I
:
Relay point zero-sequence current
0
I
m:
Adjacent line zero-sequence current
0
Z
:
Fault point - relay point positive-sequence impedance
1
Z
:
Fault point - relay point zero-sequence impedance
0
Z
m:
Adjacent line zero-sequence mutual impedance
0
Considering the faulted phase voltage V a F at the point of fault is,
Phase-A voltage V a at the relay is calculated from the following equation:
=
Where, I a is the current of phase-A at the relay and is defined in the following equation
by the symmetrical component of the current:
Here, defining the current synthesized using the phase-A current at the relay as I a ', and
Then equation (2.1-11) can be re-written in the following form:
=
×
1
1
=
×
2
1
=
×
+
×
0
0
0
0
=
+
+
1
2
+
+
=
(
+
1
2
0
1
=
+
1
(
−
)
0
1
'
I
=
+
×
a
0
1
- 27 -
+
1
1
+
2
2
+
0
0
= 0
0
−
0
1
0
×
+
×
0
0
1
1
+
2
0
+
/
×
0
1
0
6F2S1915 (0.46)
(2.1-7)
(2.1-8)
(2.1-9)
(2.1-10)
(2.1-11)
)
(2.1-12)
(2.1-13)
GRZ200 (Soft 031 & 032)