GE D90 Plus Instruction Manual page 319

CHAPTER 7: PROTECTION
Directional comparison unblocking
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
RX1, RX2, RX3, RX4
Range: any FlexLogic operand
Default: OFF
These settings allow the user to select the FlexLogic operands that represent the receive
signals for the directional comparison blocking scheme. Typically input contacts
interfacing with a signaling system are used as follows:
– In single-bit applications,
– In two-bit applications,
– In four-bit applications,
Events
Range: Enabled, Disabled
Default: Enabled
This setting enables and disables the logging of directional comparison blocking scheme
events in the sequence of events recorder.
The figure shows the directional comparison blocking scheme logic.
Figure 261: Directional comparison blocking scheme logic
The directional comparison unblocking scheme is available for single-pole tripping
applications and can be used with one, two, or four bit communications channels. Choices
of communications channel include remote inputs, remote outputs, and
telecommunications interfaces.
must be used
RX1
and must be used
RX1 RX2
through must be used
RX1 RX4
CONTROL ELEMENTS
309