D
A
1 p–( ) Z×
L
Z
B
+
Z
A
Z
L
Z
B
+ +
-----------------------------------------
=
EQUATION97 V1 EN (Equation 60)
Thus, the general fault location equation for a single line is:
FA
A A L F
A
I
V I p Z R
D
= × × + ×
EQUATION1596 V1 EN (Equation 61)
Table 248: Expressions for V
A
, I
A
and I
FA
for different types of faults
Fault type: V
A
I
A
I
FA
AG V
AA
I
AA
+ K
N
x I
NA
EQUATION1597 V1 EN
BG V
BA
I
BA
+ K
N
x I
NA
EQUATION1598 V1 EN
CG V
CA
I
CA
+ K
N
x I
NA
EQUATION1599 V1 EN
ABC, AB, ABG V
AA
-V
BA
I
AA
- I
BA
DI
ABA
BC, BCG V
BA
-V
CA
I
BA
- I
CA
DI
CBA
CA, CAG V
CA
-V
AA
I
CA
- I
AA
DI
CAA
The K
N
complex quantity for zero-sequence compensation for the single line is equal to:
K
N
Z
0L
Z
1L
–
3 Z
1L
×
------------------------
=
EQUATION99 V1 EN (Equation 62)
DI is the change in current, that is the current after the fault minus the current before
the fault.
In the following, the positive sequence impedance for Z
A
, Z
B
and Z
L
is inserted into
the equations, because this is the value used in the algorithm.
For double lines, the fault equation is:
1MRK 505 277-UUS C Section 12
Monitoring
305
Technical Manual
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