ABB REC650 - Page 483

Thus, the general fault location equation for a single line is:
U
A
I
A
p Z
L
I
FA
D
A
--------
R
F
×+× ×=
EQUATION98 V1 EN (Equation 64)
Table 411: Expressions for U
A
, I
A
and I
FA
for different types of faults
Fault type: U
A
I
A
I
FA
L1-N U
L1A
I
L1A
+ K
N
x I
NA
3
2
---
D I
L1A
I
0A
–( )´
EQUATION110 V1 EN
L2-N
U
L2A
I
L2A
+ K
N
x I
NA
3
2
---
D I
L2A
I
0A
–( )´
EQUATION111 V1 EN
L3-N
U
L3A
I
L3A
+ K
N
x I
NA
3
2
--- D I
L3A
I
0A
–( )´
EQUATION112 V1 EN
L1-L2-L3, L1-L2,L1-L2-
N
U
L1A
-U
L2A
I
L1A
- I
L2A
DI
L1L2 A
EQUATION113 V1 EN
L2-L3, L2-L3-N U
L2A
-U
L3A
I
L2A
- I
L3A
DI
L2L3A
EQUATION114 V1 EN
L3-L1, L3-L1-N
U
L3A
-U
L1A
I
L3A
- I
L1A
DI
L3L1A
EQUATION115 V1 EN
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 65)
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 511 287-UEN A Section 12
Monitoring
477
Technical manual