Setting Guidelines - Hitachi 670 Series Application Manual

Section 4
Analog and binary signal transfer for line differential protection
Name
CH4
CH5
CH6
CH7
CH8
CH9
4.8.4

Setting guidelines

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
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.
54
Type
STRING
STRING
STRING
STRING
STRING
STRING
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.
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Description
Remote communication channel 4, 2M
Remote communication channel 5, 2M
Remote communication channel 6, 2M
Remote communication channel 7, 2M
Remote communication channel 8, 2M
Remote communication channel 9, 2M
Communication set-up, 670/650 series
1MRK505382-UEN Rev. K
M12454-3 v10
Application Guide