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350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S4 CONTROLS
CHAPTER 6: SETPOINTS
The Automatic Reclosure function is designed to perform up to four breaker
autoreclosings, with a configurable dead time before each reclosing shot. Upon AR
function enabled, and breaker status “closed”, the AR is set into “AR Ready” state. If an
intermittent feeder fault occurs such as overhead conductor touching tree branch, one or
more of the overcurrent protection elements enabled under AR initiate menu will operate
and issue a breaker trip command. If the breaker opens, the dead time configured under
the first AR shot will start timing out. After this time expires, the AR scheme will produce the
first breaker reclosing shot. Upon breaker close and no fault conditions, the overcurrent
elements set for initiation on the first AR shot will not operate, and the reclosing is declared
successful. The remaining of the configured AR sequence will be executed. The AR Reset
time will start timing out, where upon time expiry resets the AR counter. The AR sequence is
reset with AR function into “AR Ready” state.
If the fault is permanent, the configured AR sequence will be executed in full, where the
breaker opens after the last reclosing shot and the AR function goes into lockout.
The reclosure scheme passes through the following states during operation:
AR NOT READY
: When in this state, the AR is blocked. The AR NOT READY occurs if any of
the following conditions are present:
•
The maximum shot number was reached.
•
The incomplete sequence AR INCOM SEQ TIME timer times out.
•
The AR BLOCK INPUT is set
AR READY
: To reach this state the AR RESET NOT READY timer times out from NOT READY
state or the AR RESET TIME timer times out from WAIT RST TIME state. In this state the
autorecloser is waiting for reclose Initiation (RI) event to start the reclosure process.
WAIT FOR 52 OPEN
: Once a Reclose Initiation event occurs the autorecloser is waiting for
breaker status OPEN or otherwise the AR INCOM SEQ TIME timer will time out. If the AR
INCOM SEQ TIME expires, the autorecloser will go into NOT READY state. However if the
breaker opens, the AR scheme will start the configured DEAD TIME timer, and will be put
into WAIT DEAD TIME state.
WAIT DEAD TIME
: In this state the autorecloser is waiting for the relevant AR DEAD TIME
SHOT timer to time out. If during this time out the breaker status changes to CLOSE, a
Reclose Initiation or an AR BLOCK input occurs the autorecloser process ends in a NOT
READY state. If not, the WAIT FOR 52 CLOSE state is reached.
WAIT FOR 52 CLOSE
: In this state upon reclosing command, the autorecloser is waiting for
the breaker to CLOSE. If the AR INCOM SEQ TIME timer times out or a new Reclose Initiation
occurs and it’s the last shot then the autorecloser ends in a NOT READY state. If a new
Reclose Initiation occurs and it is not the last from the programmed sequence, the
autorecloser goes into the WAIT FOR 52 OPEN status.
WAIT RESET TIME
: In this state, when the AR RST TIME timer times out the number of shots
is reset and the autorecloser goes into AR READY state waiting for a new AR execution.If
the breaker status changes to OPEN or an AR BLOCK input occurs, or a new
Reclose
Initiation
happens and it’s the last shot then the autorecloser ends in a NOT READY state.
If a new
Reclose Initiation
different from the last shot occurs the autorecloser goes into the
WAIT FOR 52 OPEN status for the next shot.
Reclose Initiation
is produced by a trip with the relevant permission enabled.
