GE C60 Instruction Manual page 134

5.6 CONTROL ELEMENTS
This feature can be also used when a transformer is tapped from the protected line and a reclose is not desirable until the
transformer is disconnected from the line. In this situation the reclose scheme will be "paused" until the transformer is dis-
connected.
The input will force a three-pole trip through the
AR PAUSE
EVOLVING FAULTS:
8 ms after the single pole dead time has been initiated, the "AR FORCE 3P TRIP" operand is set and it will be reset only
when the scheme is reset or goes to Lockout. This will ensure that when a fault on one phase evolves to include another
phase during the single pole dead time of the auto-recloser the scheme will force a 3 pole trip and reclose.
RECLOSING SCHEME OPERATION FOR ONE BREAKER:
• Permanent Fault: Consider mode No.1 which calls for 1-Pole or 3-Pole time delay No. 1 for the first reclosure and 3-
Pole time delay No. 2 for the second reclosure, and assume a permanent fault on the line. Also assume the scheme is
in the Reset state. For the first single-phase fault the
phase fault the
AR 3-P DEAD TIME 1
started for the first shot.
If
AR MAX NO OF SHOTS
detected by protection and reclose is initiated. The breaker is tripped three-pole through the "AR SHOT COUNT >0"
that will set the "AR FORCE 3P" operand. Because the shot counter has reached the maximum number of shots per-
mitted the scheme is sent to the Lockout state.
If
AR MAX NO OF SHOTS
detected by protection and reclose is initiated. The breaker is tripped three-pole through the "AR SHOT COUNT >0"
that will set the "AR FORCE 3P" operand. After the second reclose the shot counter is set to 2. Upon reclosing, the
fault is again detected by protection, the breaker is tripped three-pole, and reclose is initiated again. Because the shot
5
counter has reached the maximum number of shots permitted the scheme is sent to the lockout state.
• Transient Fault: When a reclose output signal is sent to close the breaker the reset timer is started. If the reclosure
sequence is successful (there is no initiating signal and the breaker is closed) the reset timer will time out returning the
scheme to the reset state with the shot counter set to "0" making it ready for a new reclose cycle.
RECLOSING SCHEME OPERATION FOR TWO BREAKERS:
• Permanent Fault: The general method of operation is the same as that outlined for the one breaker applications
except for the following description, which assumes
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 will initiate 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 will stop the transfer timer. After the 3-P dead time times out the close breaker 1 signal will close first breaker
again and will start the transfer timer. Since the fault is permanent the protection will trip again initiating the autoreclose
scheme that will be sent to Lockout by the "Shot Count = Max" signal.
• Transient Fault: When the first reclose output signal is sent to close breaker 1, the reset timer is started. The close
breaker 1 signal initiates the transfer timer that times out and sends the close signal to the second breaker. If the reclo-
sure sequence is successful (both breakers are closed and there is no initiating signal) the reset timer will time out,
returning the scheme to the reset state with the shot counter set to 0. The scheme will be ready for a new reclose
cycle.
AR BKR1(2) RECLS FAIL:
If the selected sequence is "1–2" or "2–1" and after the first or second reclose attempt the breaker fails to close, there are
two options. If the
AR BKR 1(2) FAIL OPTION
is set to "Continue", the reclose process will continue with Breaker No. 2. At the same time the shot counter will be
OPTION
decreased (since the closing process was not completed).
SCHEME RESET AFTER RECLOSURE:
When a reclose output signal is sent to close either breaker 1 or 2 the reset timer is started. If the reclosure sequence is
successful (there is no initiating signal and the breakers are closed) the reset timer will time out, returning the scheme to
the reset state, with the shot counter set to 0, making it ready for a new reclose cycle.
5-70
timer will be started. If the
is set to "1", upon the first reclose the shot counter is set to 1. Upon reclosing, the fault is again
is set to "2", upon the first reclose the shot counter is set to 1. Upon reclosing, the fault is again
AR BKR SEQUENCE
is set to "Lockout", the scheme will go to lockout state. If the
C60 Breaker Management Relay
path.
3-P DEADTIME 2
timer will be started, while for the first multi-
AR 1-P DEAD TIME
signal is high, the
AR 3P TD INIT
is set to "1-2" (reclose breaker 1 before breaker
5 SETTINGS
will be
AR 3-P DEAD TIME 2
AR BKR 1(2) FAIL
GE Multilin