312
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CONTROL ELEMENTS
CHAPTER 7: PROTECTION
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 are typically used.
These settings must be used in conjunction with the loss-of-guard signals, otherwise the
scheme will not unblock and thus fail 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 are typically 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 directional comparison unblocking scheme logic is shown below.
