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.
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.
Using
Echo
in this case is safe only if there is no risk of varying transmission
asymmetry.
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.
1MRK 505 370-UEN D Section 18
Remote communication
Busbar protection REB670 423
Application manual
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