ABB RELION REX640 - Page 663

STR_LS_LOC
STR_LS_REM
OPR_LS_LOC
OPR_LS_REM
OPR_HS_LOC
OPR_HS_REM
OPR_LS_A
OPR_LS_B
OPR_LS_C
Stabilized
low stage
OR
SEND
STR_LS_A
STR_LS_B
STR_LS_C
OR
SEND
OPR_HS_A
OPR_HS_B
OPR_HS_C
OR
SEND
OPR_LS_A
OPR_LS_B
OPR_LS_C
OR
RECEIVE
STR_LS_A
STR_LS_B
STR_LS_C
OR
RECEIVE
OPR_HS_A
OPR_HS_B
OPR_HS_C
OR
RECEIVE
Inst.
high stage
START
OPERATE
OR
OR
Figure 374: Operation logic of the direct intertrip function
The start and operate signals are provided separately for the low and high stages,
and in the local and remote.
Blocking functionality
There are two independent inputs that can be used for blocking the function: BLOCK
and BLOCK_LS. The difference between these inputs is that BLOCK_LS (when TRUE)
blocks only the stabilized low stage leaving the instantaneous high stage operative.
BLOCK (when TRUE) blocks both stages and also the PRO_ACTIVE output is updated
according to the BLOCK input status, as described in the Fail safe function chapter.
The BLOCK and BLOCK_LS input statuses affect only the behavior of the local
protection instance. When a line differential protection stage (stabilized low
or instantaneous high) is blocked, also the received remote signals related to
the corresponding stage are ignored (received direct inter-trip signals from the
remote end). The binary signal transfer functionality should therefore be used for
1MRS759142 F
Protection functions
REX640
Technical Manual
663