CHAPTER 7: PROTECTION CONTROL ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 315
RX1, RX2, RX3, RX4
Range: any FlexLogic operand
Default: OFF
These settings select FlexLogic operands to represent the permission receive signals for
the scheme. Contact inputs interfacing with a signaling system typically are used. These
settings must be used in conjunction with the loss-of-guard signals, otherwise the
scheme does not unblock and thus fails to operate. These settings are used as follows:
– In single-bit applications,
RX1 must be used
– In two-bit applications,
RX1 and RX2 must be used
– In four-bit applications,
RX1 through RX4 must be used
Loss of Guard 1, Loss of Guard 2, Loss of Guard 3, Loss of Guard 4
Range: any FlexLogic operand
Default: OFF
These settings select FlexLogic operands to represent the loss-of-guard receive signals
for the scheme. Contact inputs interfacing with a signaling system typically are used.
Each loss-of-guard signal must correspond to the same receive signal from the same
communications channel (that is,
RX1 and Loss of Guard 1 must be from the same
communications channel, and the same for channels 2, 3 and 4, if used). These settings
are used as follows:
– In single-bit applications,
Loss of Guard 1 and RX1 must be used
– In two-bit applications,
Loss of Guard 1 with RX1 and Loss of Guard 2 with RX2
must be used
– In four-bit applications, all receive and loss-of-guard signals must be used
Events
Range: Enabled, Disabled
Default: Enabled
This setting enables and disables the logging of directional comparison unblocking
scheme events in the sequence of events recorder.
The figures show the directional comparison unblocking scheme logic.
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