Merging Unit - ABB RELION 670 SERIES Applications Manual

1MRK 506 369-UUS -
20.3
20.3.1
Line distance protection REL670 2.2 ANSI
Application manual
IEC16000039 V1 EN
Figure 403: ECT screen with Redundancy set to PRP-1 on Access point 1 and HSR
Access point 3

Merging unit

Application
The IEC/UCA 61850-9-2LE process bus communication protocol enables an IED to
communicate with devices providing measured values in digital format, commonly
known as Merging Units (MU). The rear access points are used for the 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.
Ethernet-based communication
IEC16000039-1-en.vsdx
Section 20
859