ABB REC670 Applications Manual page 549

1MRK 511 401-UEN A
Bay control REC670 2.2 IEC
Application manual
local
IED
MU
IEC13000298 V2 EN-US
Figure 227: Normal operation
Case 2:
Failure of the MU (sample lost) blocks the sending of binary signals through
LDCM. The received binary signals are not blocked and processd normally.
→DTT from the remote end is still processed.
local
IED
MU
IEC13000299 V2 EN-US
Figure 228: MU failed, mixed system
Case 3:
Failure of one MU (sample lost) blocks the sending and receiving of binary signals
through LDCM.
→DTT from the remote end is not working.
Direct transfer trip (DTT)
OK
OK
IEC13000298-2-en.vsd
Direct transfer trip (DTT)
Not OK
OK
IEC13000299-2-en.vsd
Section 20
Station communication
remote
IED
remote
IED
543