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PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
DIRECT INPUTS AND OUTPUTS
CHAPTER 6: COMMUNICATIONS
Table 11: Expected delivery times for healthy rings
This configuration can be applied to both permissive and blocking schemes.
Direct inputs and outputs statistics
Select the
Actual Values > Communications > Direct IO Statistics
menu item to open the
direct inputs and outputs statistics window.
Figure 140: Direct inputs and outputs statistics
The following actual values are available for each channel and are applicable to all direct
inputs and direct outputs.
Message Return Time
Range: 0 to 10000 ms in steps of 1
This actual value displays the time taken for direct output messages to return to the
sender. There are two return times (one for each channel) for dual-channel
communications modules. The value is defaulted to the maximum “10000 ms” if the
message is not received or if the ring configuration function setting is “Disabled”.
CRC Fail Count
Range: 0 to 65535 in steps of 1
These actual values (one per communications channel) display the number of direct
output messages that have been received but fail the CRC check. High values may
indicate a problem with wiring or the communication channel on one or more devices.
This value can be reset to zero using the Clear Direct I/O Counters command.
Unreturned Message Count
Range: 0 to 65535 in steps of 1
These actual values (one per communications channel) display the number of direct
output messages that do not complete the trip around the communications ring. High
values may indicate a problem with wiring or the communication channel on one or
more devices. This value can be reset to zero using the Clear Direct I/O Counters
command. If the
Message Alarm Function
setting is changed to “Disabled”, then this
value is frozen to the value at the time of change.
Direct inputs and outputs commands
Select the
Actual Values > Communications > Commands > Commands
menu item to
open the inter-relay communications commands.
Path
Delivery time
IED 1 to IED 2
0.2 of a power system cycle
IED 1 to IED 3
0.2 of a power system cycle
IED 2 to IED 3
0.2 of a power system cycle