ABB RER620 Technical Manual page 261

1MAC309294-MB F
RER620
Technical Manual
Table 267: Fault identification
Fault in phase A Fault in phase B
1 0
0 1
0 0
1 1
0 1
1 0
1 1
1 1
0 1
1 0
1 1
0 0
Once the specific fault type is determined, the respective fault loop voltage and current
phasor are taken for fault location algorithm.
If the fault is any single phase to ground fault, then the respective phase current should be
ground compensated.
The procedure for the ground compensation is given below,
For ground fault cases, the current measured at the relay is ground compensated by
employing the following formula:
 
*
I I k * I ( * ZL
rly rly 0 zero
where
  
I ( I _ A I _ B I _
0
k = 1.0 (scaling factor)
ZL and ZL refer to positive and zero sequence line impedances.
pos zero
ZL = RL + j*XL
pos pos pos
ZL = RL + j*XL
zero zero zero
RL = PosSeqR * LinLen
pos
XL = PosSeqX * LinLen
pos
RL = ZeroSeqR * LinLen
zero
XL = ZeroSeqX * LinLen
zero
*
I
= Ground compensated phase current
rly
I = Non-compensated phase current
rly
Fault in phase C Fault in ground (Io)
0
0
1
0
1
1
1
0
1
1
1
0

ZL / ) ZL
pos pos
C ) 3 /
Section 4
Protection functions
FLTLOOP FLTLOOP
1 AG Fault
1 BG Fault
1 CG Fault
1 AB Fault
1 BC Fault
1 CA Fault
1 ABC Fault
0 ABG Fault
0 BCG Fault
0 CAB Fault
0 ABCG Fault
0 No Fault
Equation (37)
Equation (38)
1
2
3
4
5
6
7
-1
-2
-3
-4
0
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