GE D90 Plus Instruction Manual page 412

AUTOMATION CONTROL
404
3-Bit Mode
Range: Time-out, Acknowledge
Default: Time-out
This setting selects the selector mode of operation. When set to "Time-out", the selector
changes its position after a pre-defined period of inactivity at the control input. The
change is automatic and does not require explicit confirmation to change the selector
position. When set to "Acknowledge", the selector changes its position only after
confirmation through a separate acknowledging signal. If the acknowledging signal
does not appear within a pre-defined period of time, the selector rejects the change and
an alarm established by invoking the
seconds.
3-Bit Acknowledge
Range: any automation logic operand or shared operand
Default: OFF
This setting selects an acknowledging input for the three-bit control input. The pre-
selected position is applied on the rising edge of the assigned operand. This setting is
active only under the acknowledge mode of operation. The acknowledging signal must
appear within the time defined by the
bit control inputs. Note that the stepping up control input and three-bit control input
have independent acknowledging signals (the
operands, accordingly).
Power-Up Mode
Range: Restore, Synchronize, Sync/Restore
Default: Restore
This setting selects the selector switch behavior on power up of the relay.
When set to "Restore", the last position of the selector (stored in the non-volatile
memory) is restored after powering up the relay. If the position restored from memory is
out of range, position 0 (no output operand selected) is applied and an alarm is set
(SELECTOR 1 PWR ALARM).
When set to "Synchronize", the selector switch acts as follows. For two power cycles, the
selector applies position 0 to the switch and activates the
operand. After two power cycles expire, the selector synchronizes to the position
dictated by the three-bit control input. This operation does not wait for time-out or the
acknowledging input. When the synchronization attempt is unsuccessful (that is, the
three-bit input is not available (0,0,0) or out of range) then the selector switch output is
set to position 0 (no output operand selected) and an alarm is established (the
operand is asserted).
PWR ALARM
The operation of the "Synch/Restore" mode is similar to the "Synchronize" mode. The
only difference is that the switch will attempt to restore the position stored in the relay
memory after an unsuccessful synchronization attempt. The synch/restore mode is
useful for applications where the selector switch is employed to change the setting
group in redundant (two relay) protection schemes.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of selector switch events in the sequence
of events recorder. If enabled, the following events are logged.
Selector switch events
SELECTOR 1 POS 1 ................. Selector 1 changed its position to 1.
SELECTOR 1 POS 2 ................. Selector 1 changed its position to 2.
SELECTOR 1 POS 3 ................. Selector 1 changed its position to 3.
SELECTOR BIT ALARM
setting after the last activity of the three-
Timeout
SELECTOR 1 ACK
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 8: AUTOMATION
FlexLogic™ operand for 3
and
SELECTOR 1 3BIT ACK
SELECTOR 1 PWR ALARM
SELECTOR 1