ABB Relion 670 Series Technical Reference Manual page 820

Section 13
Scheme communication
814
measuring and the directional ground-fault current system of the healthy line may
detect a fault in different directions, which could result in unwanted tripping.
Common channels cannot be used when the weak-end infeed function is used in the
distance or ground-fault protection.
In case of an internal ground-fault, the forward directed measuring element operates
and sends a permissive signal to the remote end via the CS output (sent signal). Local
tripping is permitted when the forward direction measuring element operates and a
permissive signal is received via the CR binary input (received signal).
The permissive scheme can be of either underreaching or overreaching type. In the
underreaching alternative, an underreaching directional residual overcurrent
measurement element will be used as sending criterion of the permissive input signal
CSUR.
In the overreaching alternative, an overreaching directional residual overcurrent
measurement element will be used as sending criterion of the permissive input signal
CSOR. Also the underreaching input signal CSUR can initiate sending.
BLOCK
CR
PLTR_CRD
BLKCS
Overreach
AND
CSOR
CSUR
ANSI05000280 V1 EN
AND
0-tCoord
AND AND
AND
AND
50ms
OR
0
1MRK505222-UUS C
0
25ms
0
0
50ms
OR
en05000280_3_ansi.vsd
Technical reference manual
CRL
TRIP
CS