GE D90 Plus Instruction Manual page 353

CHAPTER 7: PROTECTION
Autoreclose pause input
Dual breaker operation
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 284: Autoreclose shot counter logic
The autoreclose pause input offers the possibility of freezing the autoreclose cycle until the
pause signal disappears. This can be done when a trip occurs and simultaneously or
previously, some conditions are detected such as out-of step or loss of guard frequency, or
a remote transfer trip signal is received. The pause signal blocks all three dead timers.
When the pause signal disappears, the autoreclose cycle is resumed by initiating the
operand.
DEAD TIME 2
This feature can be also used when a transformer is tapped from the protected line and a
reclose is not wanted until the transformer is removed from the line. In this case, the
reclose scheme is paused until the transformer is disconnected. The
a three-pole trip through the
Figure 285: Autoreclose multi-shot supervision logic
The operation for two-breaker reclosing on a permanent fault is the same as that outlined
for the single-breaker application, except as follows, which assumes the
setting is "1-2" (reclose breaker 1 before breaker 2). The signal output from the dead time
timers passes through the breaker selection logic to initiate reclosing of breaker 1. The
CLOSE BREAKER 1 signal initiates the transfer timer. After the reclose of the first breaker,
the fault is again detected by the protection, the breaker is tripped three-pole, and the
autoreclose scheme is initiated. The INITIATE signal stops the transfer timer. After the three-
pole dead time times out, the CLOSE BREAKER 1 signal closes the first breaker again and
starts the transfer timer. Since the fault is permanent, the protection trips again and
initiates the autoreclose scheme that is sent to lockout by the SHOT COUNT = MAX signal.
path.
3-P Dead Time 2
CONTROL ELEMENTS
AR 3-P
input forces
AR PAUSE
Breaker Sequence
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