ABB Relion 670 Series Applications Manual page 461

1MRK 505 370-UUS Rev. K
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
OutOfService
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.
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
DiffSync defines the method of time synchronization for the line differential function: Echo or GPS.
GPSSyncErr: when GPS synchronization is lost, synchronization of the line differential function continues
for 16 s based on the stability in the local IED clocks. After that, setting Block blocks the line differential
function or setting Echo keeps it on by using the Echo synchronization method.
CommSync defines the Master and Slave relation in the communication system, and should not be
mistaken for the synchronization of line differential current samples. When direct fiber is used, one LDCM
is set as Master and the other as Slave. When a modem and multiplexer is used, the IED is always set
as Slave because the telecommunication system provides the clock master.
OptoPower has two settings: LowPower and HighPower.
Busbar protection REB670
Application manual
IED does not use data from the LDCM
IED informs the remote end that it is out of service
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.
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.
Using Echo in this case is safe only if there is no risk of varying transmission asymmetry.
Using Echo in this case is safe only if there is no risk of varying transmission asymmetry.
© 2017 - 2021 Hitachi Power Grids. All rights reserved
Section 18
Remote communication
455