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D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
INTER-RELAY COMMUNICATIONS
CHAPTER 6: COMMUNICATIONS
channels when the IEDs are configured in a redundant ring. This provides a greater level
of security if one of the rings become disconnected. This mode should be used when
interfacing with UR-series devices.
Inter-Relay Baud Rate
Range: 64 kbps, 128 kbps
Default: 64 kbps
This setting selects the baud rate for each inter-relay communications channel. All
interconnected devices must use the same baud rate for communications to operate
properly.
Protocol Encoding
Range: Default, G.703 Octet Internal Clock, G.703 Octet External Clock, G.703 Internal
Clock, G.703 External Clock, Diff. Manchester, C37.94 Internal Clock, C37.94 External Clock
Default: Default
For RS422 communications, only the “Default” value is available. For channels with G.703
communications, only the “Default”, “G.703 Internal Clock”, “G.703 Octet Internal Clock”.
“G.703 External Clock”, and “G.703 Octet External Clock” values are available. For
channels with fiber option communications, only the “Default”, “Diff. Manchester”,
“C37.94 Internal Clock”, and “C37.94 External Clock” values are available.
The “Default” value defaults the communications to a connection in a higher order
system as shown in the following table.
Table 12: Default value encoding
When an internal value is selected, the inter-relay communications card supplies the
clock for communications. When an external value is selected, the clock is supplied by
the external device connected to the inter-relay communications card.
Inter-relay communication actual values
The inter-relay actual values provide diagnostics to troubleshoot the inter-relay card in the
event there is a problem. These values are useful for the factory and the user in the event
the inter-relay card is not functioning properly. Each fiber transceiver contains a digital
diagnostic monitoring interface (DDMI) that provides the transceiver actual values. Select
the
Actual Values > Communications > Inter-Relay Transceivers
menu item to open the
inter-relay communication actual values window.
Protocol encoding
Channel type
G.703
Fiber
RS422
Octet timing
Enabled
N/A
N/A
Timing
External clock
External clock
N/A
Fiber protocol
N/A
C37.94
N/A
