GE Digital Energy L30, Instruction Manual, Page: 439 / 644

GE Multilin L30 Line Current Differential System 9-21
9 THEORY OF OPERATION 9.3 FAULT LOCATOR
9
For BG faults:
(EQ 9.44)
For CG faults:
(EQ 9.45)
For AB and ABG faults:
(EQ 9.46)
For BC and BCG faults:
(EQ 9.47)
For CA and CAG faults:
(EQ 9.48)
where K
0
is the zero sequence compensation factor (for the first six equations above)
For ABC faults, all three AB, BC, and CA loops are analyzed and the final result is selected based upon consistency of the
results
The element calculates the distance to the fault (with m in miles or kilometers) and the phases involved in the fault.
The relay allows locating faults from delta-connected VTs. If the
FAULT REPORT 1 VT SUBSTITUTION
setting is set to “None”,
and the VTs are connected in wye, the fault location is performed based on the actual phase to ground voltages. If the VTs
are connected in delta, fault location is suspended.
If the
FAULT REPORT 1 VT SUBSTITUTION
setting value is “V0” and the VTs are connected in a wye configuration, the fault
location is performed based on the actual phase to ground voltages. If the VTs are connected in a delta configuration, fault
location is performed based on the delta voltages and externally supplied neutral voltage:
(EQ 9.49)
If the
FAULT REPORT 1 VT SUBSTITUTION
setting value is “I0” and the VTs are connected in a wye configuration, the fault loca-
tion is performed based on the actual phase to ground voltages. If the VTs are connected in a delta configuration, fault loca-
tion is performed based on the delta voltages and zero-sequence voltage approximated based on the zero-sequence
current:
(EQ 9.50)
where Z
SYS 0
is the equivalent zero-sequence impedance behind the relay as entered under the fault report setting menu.
V
A
V
A
B
, I
A
I
A
B
K
0
I
0 A

V
A
V
A
C
, I
A
I
A
BC
K
0
I
0 A

V
A
V
A
A
V
A
B
, I
A
I
A
A
I
A
B
V
A
V
A
B
V
A
C
, I
A
I
A
B
I
A
C
V
A
V
A
C
V
A
A
, I
A
I
A
C
I
A
A
V
A
1
3
---
V
N
V
AB
V
CA
 
V
B
1
3
--- V
N
V
BC
V
AB
 
V
B
1
3
---
V
N
V
CA
V
BC
 
V
A
1
3
---
V
AB
V
CA
 
Z
SYS 0
I
0
V
B
1
3
--- V
BC
V
AB
 
Z
SYS 0
I
0
V
B
1
3
---
V
CA
V
BC
 
Z
SYS 0
I
0