ABB Relion 670 Series Applications Manual page 485

1MRK 511 358-UUS A
TerminalNo : This setting shall be used to assign an unique address to each LDCM, in all current
differential IEDs. Up to 256 LDCMs can be assigned a unique number. Consider a local IED with two
LDCMs:
• LDCM for slot 302: Set
• LDCM for slot 303: Set
In multiterminal current differential applications, with 4 LDCMs in each IED, up to 20 unique
addresses must be set.
RemoteTermNo : This setting assigns a number to each related LDCM in the remote IED. For each
LDCM, the parameter
but equal to the
RemoteTermNo settings are reversed as follows:
• LDCM for slot 302: Set
• LDCM for slot 303: Set
DiffSync : Here the method of time synchronization, Echo or GPS , for the line differential function is
selected.
GPSSyncErr : If GPS synchronization is lost, the synchronization of the line differential function will
continue during 16 s. based on the stability in the local IED clocks. Thereafter the setting
block the line differential function or the setting
synchronization method. It shall be noticed that using
there is no risk of varying transmission asymmetry.
CommSync : This setting decides the Master or Slave relation in the communication system and
shall not be mistaken for the synchronization of line differential current samples. When direct fibre
is used, one LDCM is set as
used, the IED is always set as
master.
OptoPower has two settings: LowPower and HighPower .
Application manual
TerminalNo to 1 and RemoteTermNo to 2
TerminalNo to 3 and RemoteTermNo to 4
The unique address is necessary to give high security against incorrect addressing
in the communication system. Using the same number for setting
some of the LDCMs, a loop-back test in the communication system can give
incorrect trip.
RemoteTermNo shall be set to a different value than parameter TerminalNo ,
TerminalNo of the remote end LDCM. In the remote IED the TerminalNo and
TerminalNo to 2 and RemoteTermNo to 1
TerminalNo to 4 and RemoteTermNo to 3
The redundant channel is always configured in the lower position, for example
• Slot 302: Main channel
• Slot 303: Redundant channel
The same is applicable for slot 312-313 and slot 322-323.
Echo in this situation is safe only as long as there is no risk of varying
Using
transmission asymmetry.
Master and the other one as Slave . When a modem and multiplexer is
Slave , as the telecommunication system will provide the clock
Echo will make it continue by using the Echo
Echo in this situation is only safe as long as
Section 19
Remote communication
TerminalNo in
Block will
479