ABB Relion 670 Series Applications Manual page 462

Section 18
Station communication
The merging units (MU) are called so because they can gather analog values from one or more
measuring transformers, sample the data and send the data over process bus to other clients (or
subscribers) in the system. Some merging units are able to get data from classical measuring
transformers, others from non-conventional measuring transducers and yet others can pick up
data from both types. The electronic part of a non-conventional measuring transducer (like a
Rogowski coil or a capacitive divider) can represent a MU by itself as long as it can send sampled
data over process bus.
IEC08000069 V2 EN-US
Figure 214: Example of a station configuration with the IED receiving analog values from
456
Station Wide
SCADA System
Other
Relays
CT
both classical measuring transformers and merging units.
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 511 358-UUS A
Station Wide
GPS Clock
Splitter
Electrical-to-
Optical Converter
1PPS
1PPS
en08000069-3.vsd
Application manual