Application - ABB REL670 2.2 IEC Applications Manual

Section 16
Scheme communication
16.7.2
16.7.2.1
724

Application

Fault current reversal logic
Figure 374 and figure 375
fault current reversal.
Assume that fault is near the B1 breaker. B1 Relay sees the fault in Zone1 and A1
relay identifies the fault in Zone2.
Note that the fault current is reversed in line L2 after the breaker B1 opening.
It can cause an unselective trip on line L2 if the current reversal logic does not
block the permissive overreaching scheme in the IED at B2.
A1
A2
IEC99000043 V3 EN-US
Figure 374: Current distribution for a fault close to B side when all breakers are
closed
A1
A2
IEC99000044 V3 EN-US
Figure 375: Current distribution for a fault close to B side when breaker at B1 is
opened
When the breaker on the parallel line operates, the fault current on the healthy line
is reversed. The IED at B2 recognizes the fault in forward direction from reverse
direction before breaker operates. As IED at B2 already received permissive signal
from A2 and IED at B2 is now detecting the fault as forward fault, it will
immediately trip breaker at B2. To ensure that tripping at B2 should not occur, the
permissive overreaching function at B2 needs to be blocked by IRVL till the
received permissive signal from A2 is reset.
The IED at A2, where the forward direction element was initially activated, must
reset before the send signal is initiated from B2. The delayed reset of output signal
IRVL also ensures the send signal from IED B2 is held back till the forward
direction element is reset in IED A2.
show a typical system condition, which can result in a
L1
B1
L2
B2
IEC9900043-2.vsd
L1
B1
L2
B2
IEC99000044-2.vsd
1MRK 506 369-UEN B
Line distance protection REL670 2.2 IEC
Application manual
IP15041-1 v1
M15285-3 v7