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5.7 CONTROL ELEMENTS
BASIC RECLOSING OPERATION:
Reclosing operation is determined primarily by the
started by the initiate inputs. A reclose initiate signal sends the scheme into the reclose-in-progress (RIP) state, asserting
the
FlexLogic operand. The scheme is latched into the RIP state and resets only when an
AR RIP
close breaker 1) or
AR CLS BKR 2
The dead time for the initial reclose operation is determined by either the
setting, depending on the fault type and the mode selected. After the dead time interval the scheme asserts the
DEAD TIME 2
or
AR CLOSE BKR 1
AR CLOSE BKR 2
the breaker closes or the scheme goes to Reset or Lockout.
There are three initiate programs: single pole initiate, three pole initiate and three pole, time delay initiate. Any of these
reclose initiate signals start the reclose cycle and set the reclose-in-progress (
operand is sealed-in until the Lockout or Reset signal appears.
The three-pole initiate and three-pole time delay initiate signals are latched until the
Reset signal appears.
AR PAUSE:
The 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 fre-
quency, or a remote transfer trip signal is received. The pause signal freezes all four dead timers. When the 'pause' signal
disappears the autoreclose cycle is resumed by continuing the shot timer it was left at when paused.
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 removed from the line. In this case, the reclose scheme is 'paused' until the transformer is disconnected. The
input will force a three-pole trip through the
AR PAUSE
5
EVOLVING FAULTS:
1.25 cycles after the single pole dead time has been initiated, the
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 1, which calls for 1-Pole or 3-Pole Time Delay 1 for the first reclosure and 3-Pole
Time Delay 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
the
AR 3-P DEAD TIME 1
the first shot.
If
AR MAX NO OF SHOTS
detected by protection and reclose is initiated. The breaker is tripped three-pole through the
and that will set the
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
and that will set the
fault is again detected by protection, the breaker is tripped three-pole, and reclose is initiated again. Because the shot
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
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
5-324
AR MODE
(autoreclose breaker 2) operand is generated or the scheme goes to the Lockout state.
operands, as determined by the sequence selected. These operands are latched until
AR 1-P DEAD TIME
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
operand. Because the shot counter has reached the maximum number of shots per-
AR FORCE 3P
is set to "2", upon the first reclose the shot counter is set to 1. Upon reclosing, the fault is again
operand. After the second reclose the shot counter is set to 2. Upon reclosing, the
AR FORCE 3P
L90 Line Current Differential System
and
AR BKR SEQUENCE
AR 1-P DEAD TIME
AR RIP
path.
3-P DEADTIME 2
AR FORCE 3P TRIP
timer will be started, while for the first multi-phase fault
signal is high, the
AR 3P TD INIT
is "1-2" (reclose Breaker 1 before Breaker 2)
AR BKR SEQUENCE
5 SETTINGS
settings. The reclosing sequences are
AR CLS BKR 1
,
, or
AR 3-P DEAD TIME 1
) operand. The reclose-in-progress
or Lockout or
CLOSE BKR1 OR BKR2
operand is set and it will be reset only
will be started for
AR 3-P DEAD TIME 2
AR SHOT COUNT >0
AR SHOT COUNT >0
GE Multilin
(autore-
AR 3-P
oper-
oper-
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