ABB RELION REX640 Technical Manual page 1242

Protection related functions
Activating the BLOCK input totally blocks the directional comparison blocking
scheme. The CS_PRM and OPERATE outputs can be blocked by the BLK_CS_OPR
input.
Figure 707
In
the fault is not sent as it is not seen by the reverse-looking zones (Z3).
Z3
Bus A
~
Z2_START
Figure 707: Simplified functional diagram of the blocking scheme, internal fault
Figure 708
In
in the reverse direction and sends a blocking signal CS_BLOCKING to the protection
relay at bus A. There is no CB operation at either end.
1242
response times in transmitting the CS_BLOCKING signal to the other
Coordination Time setting must not be zero.
feeder end. The
, in case of internal faults, the CS_BLOCKING signal is not sent because
Z1
3
Z2
TRIP_CB_A
, in case of external faults, the protection relay at bus B sees the fault
Z2
Z1
Z2_START
1MRS759142 F
Bus B
~
3
Z3
TRIP_CB_B
REX640
Technical Manual