Link Forwarding - ABB Relion 670 Series Application Manual

1MRK 505 382-UEN E
IEC07000229 V1 EN-US
Figure 23: Typical application with redundant channels (for two or three line ends)
Redundant channels must be configured in the same way at both ends of the line differential
communication link or otherwise an unwanted trip may occur when the main channel fails and
the redundant channel is enabled. This means that it is not possible to have an LDCM for a
redundant channel only at one end.
Also, SMT configuration for the redundant channel must be left empty. The redundant channel
takes over the signal matrix configuration from the main channel when enabled. If the
redundant channel has been allocated, for example, current inputs at one end or at both ends
via the SMT tool, an unwanted trip occurs.
4.5

Link forwarding

If it is not possible to have a communication link between each station, the solution has been
to set the protection up in a slave-master-slave configuration. This means that in Figure 24,
only IED-B has access to all currents and, therefore, this is the only place where the differential
current is evaluated. If the evaluation results in a trip, the trip signal will be sent over the two
communication links.
IEC16000077 V1 EN-US
Figure 24: Three-end differential protection with two communication links
If the LDCM is in 2Mbit mode, you can send the three local currents as well as the three remote
currents from the other links by configuring the transmitters in IED-B:
Communication set-up, 670/650 series
Application Guide
Primary channel
Secondary redundant (reserve) channel
3-end differential protection with two communication links
Ldcm312
IED-A
Ldcm312
© Copyright 2017 ABB. All rights reserved
Analog and binary signal transfer for line differential protection
Telecommunication
network
Telecommunication
network
IED-B
Ldcm313
IEC07000229-1-en.vsdx
GUID-DD3CF47C-A202-4416-954A-EFC0F8BEBCB7 v1
Ldcm312
IED-C
IEC16000077-1-en.vsd
Section 4
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