ABB Relion 670 Series Applications Manual page 434

Section 17
Station communication
IEC08000069 V2 EN-US
Figure 218: Example of a station configuration with the IED receiving analog values from both
17.3.2 Faulty merging unit for bay in service
When a merging unit goes faulty while the bay is in service, the protection functions connected to that
merging unit get blocked. In the busbar protection case, the whole busbar protection is then blocked (the
zone to which the bay is connected). This also applies to protection functions in 1 1/2 circuit breaker
applications, where two SV streams from different merging units are combined.
This can be resolved by connecting external binary input signals to the BLOCK input on the respective
SMAI function blocks with the use of ACT. When the BLOCK input on a SMAI function is energized, the
428
Station Wide
SCADA System
Other
Relays
CT
classical measuring transformers and merging units.
© 2017 - 2021 Hitachi Power Grids. All rights reserved
IEC61850-8-1
IEC61850-8-1
110 V
IED
1 A
1 A
IEC61850-9-2LE
Ethernet Switch
IEC61850-9-2LE
ABB
Merging
Unit
Combi
CT
Sensor
Conventional VT
1MRK 505 370-UUS Rev. K
Station Wide
GPS Clock
Splitter
Electrical-to-
Optical Converter
1PPS
1PPS
en08000069-3.vsd
GUID-CBAB6232-91E6-487C-8C75-7150E2350A6B v1
Busbar protection REB670
Application manual