Name Type Description
CH4 STRING Remote communication channel 4, 2M
CH5 STRING Remote communication channel 5, 2M
CH6 STRING Remote communication channel 6, 2M
CH7 STRING Remote communication channel 7, 2M
CH8 STRING Remote communication channel 8, 2M
CH9 STRING Remote communication channel 9, 2M
4.8.4 Setting guidelines
M12454-3 v10
64 kbit mode common settings
ChannelMode defines how an IED discards the LDCM information when one of the IEDs in the
system is out of service: it can either be done on the IED out of service by setting all local LDCMs to
channel mode OutOfService or at the remote end by setting the corresponding LDCM to channel
mode Blocked. If OutOfService is selected, the IED should have active communication to the remote
end during the whole maintenance process, that is, no restart or removal of the fiber can be done.
This setting does not apply to two-end communication.
Blocked IED does not use data from the LDCM
OutOfService IED informs the remote end that it is out of service
TerminalNo is used to assign a unique address to each LDCM in all current differential IEDs. Up to
256 LDCMs can be assigned a unique number. For example, in a local IED with two LDCMs:
• LDCM for slot 305: set TerminalNo to 1 and RemoteTermNo to 2
• LDCM for slot 306: set TerminalNo to 3 and RemoteTermNo to 4
In multiterminal current differential applications,with 4 LDCMs in each IED, up to 20 unique
addresses must be set.
A unique address is necessary to give high security against incorrect addressing in the
communication system. If the same number is used for TerminalNo in some of the
LDCMs, a loop-back test in the communication system can give an incorrect trip.
RemoteTermNo is used to assign a number to each related LDCM in the remote IED. For each
LDCM, RemoteTermNo is set to a different value than TerminalNo, but equal to the TerminalNo of the
remote end LDCM. In the remote IED, TerminalNo and RemoteTermNo are reversed as follows:
• LDCM for slot 305: set TerminalNo to 2 and RemoteTermNo to 1
• LDCM for slot 306: set TerminalNo to 4 and RemoteTermNo to 3
The redundant channel is always configured to the lower position, for example:
• Slot 305: main channel
• Slot 306: redundant channel
The same is applicable for slot 312-313 and slot 322-323.
DiffSync defines the method of time synchronization for the line differential function: Echo or GPS.
Using
Echo in this case is safe only if there is no risk of varying transmission asymmetry.
Section 4 1MRK505382-UEN Rev. K
Analog and binary signal transfer for line differential protection
54 Communication set-up, 670/650 series
Application Guide
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