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5.8 S7 CONTROL
Set the AR RESET TIME timer to a delay longer than the INCOMPLETE SEQUENCE timer.
NOTE
•
AR BLOCK TIME UPON MANUAL CLOSE: The autoreclose scheme can be disabled for a programmable time delay
after the associated circuit breaker is manually closed. This prevents manual reclosing onto a fault. This delay must be
longer than the slowest expected trip from any protection not blocked after manual closing. If no overcurrent elements
activate after a manual close and this timer expires, the autoreclose scheme is automatically reset. The lockout state
will be cleared and the shot counter will be set to zero.
Manual circuit breaker closures can be initiated by either the front panel breaker
mode, or by the Remote Close logic input and computer communications when in remote mode.
NOTE
•
AR EXTERNAL CLOSE LOGIC: For applications where the breaker may be closed directly, without using the 760 to
provide the closing signal to the breaker, enabling this setpoint will use breaker state to determine if a manual close
has occurred. The 760 uses the detection of a manual close to disable the autoreclose scheme to prevent reclosing
onto a fault. Also, if the Autoreclose scheme is in the lockout state, a successful manual close would result in the
autoreclose scheme being automatically reset after the
When "Enabled", this setpoint uses the detection of the breaker going from the open state to the closed state to deter-
mine if a manual close has occurred. The breaker state is determined by the 52a/b contact feedback to the 760. When
set to "Disabled", only close commands sent via the 760 will be considered as a manual close for the autoreclose
scheme logic.
•
INCOMPLETE SEQUENCE TIME: This timer sets the maximum time interval allowed for a single reclose shot. It is
started whenever a reclosure is initiated and is active when the scheme is in the "Reclosure In Progress" state. If all
conditions allowing a breaker closure are not satisfied when this timer expires, the reclosure initiation is abandoned.
5
Any combinations of the following conditions block the breaker from closing:
– Breaker status logic inputs (52a or 52b contact) fail to report the breaker has opened;
– The "Block 2 Close Relay" logic input function is asserted;
– The synchrocheck feature is blocking breaker closes.
This timer must be set to a delay less than the AR RESET TIME timer.
NOTE
•
RECLOSURE ENABLED RELAYS: Select the relays required to operate while the front panel Reclosure Enabled indi-
cator is on.
•
RECLOSURE IN PROGRESS RELAYS: Select the relays required to operate while the front panel Reclosure In
Progress indicator is on. This indicator is on when the autoreclose scheme has been initiated, but has not yet sent a
close command. This output could be used to block the operation of a transformer tap changer during a reclosure
sequence.
•
RECLOSURE LOCKOUT RELAYS: Select the relays required to operate while the front panel Reclosure Lockout indi-
cator is on. This indicator is on when the autoreclose scheme has progressed to a lockout condition, such that no fur-
ther breaker closures will be initiated until the 760 has been reset.
5-120
Courtesy of NationalSwitchgear.com
AR BLOCK TIME UPON MANUAL CLOSE
750/760 Feeder Management Relay
5 SETPOINTS
key when in local
CLOSE
time has expired.
GE Multilin
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