Autoreclose (760 Only) - GE Feeder Management Relay 750 Instruction Manual

5.8 S7 CONTROL
a) MAIN MENU
PATH: SETPOINTS S7 CONTROL
AR
[ENTER] for more
5
The 760 has a very flexible autoreclose scheme that allows for the many different control strategies typical of utility applica-
tions. Up to four reclosure 'shots' are possible with separately programmable 'dead times' for each shot. Reclosure can be
initiated from any 760 overcurrent element or from external sources. Between each shot, overcurrent protection setpoints
can be adjusted in order to co-ordinate with downstream devices. To prevent breaker wear, a 'current supervision' feature
can reduce the number of shots when the fault current is high. A 'zone co-ordination' feature can maintain protection coor-
dination with downstream reclosers. Logic inputs are available for blocking and disabling the scheme.
Front panel LEDs indicate the present state of the autoreclose scheme. Note that display message group
can also be accessed to determine the present state of the autoreclose scheme.
• Reclosure Enabled: The scheme is enabled and may reclose if a trip occurs.
• Reclosure Disabled: The scheme is not enabled and will not reclose until the scheme is enabled.
• Reclosure In Progress: An autoreclosure has been initiated but the breaker has not yet been closed.
• Reclosure Lockout: The scheme has gone to 'lockout' and must be reset before further recloses are permitted.
The reclosure scheme is considered enabled when all of the following four conditions are true:
1. The
AR FUNCTION
2. Either a 52a or 52b contact is installed and has been programmed to a logic input function.
3. Neither the 'Block Reclosure' nor 'Cancel Reclosure' logic input functions are asserted.
4. The scheme is not in the lockout state.
5. The AR Block Time Upon Manual Close timer is not active.
Following is a simplified description of how the autoreclose scheme works. Refer to the logic diagrams in this section and
the Application Example on page 5–128 for further details.
A fault occurs resulting in an overcurrent element tripping the circuit breaker and initiating a reclosure. Once the breaker is
detected open a 'dead timer' is started. Once this timer exceeds the value programmed for the
Reclosure 1 setpoint, the shot counter is incremented and a breaker closure is initiated using the '2 Close' output con-
SURE
tact. At the same time, overcurrent element characteristics are modified according to the Reclosure 1 setpoints.
5-118
Courtesy of NationalSwitchgear.com
AR
ð
ENTER SCHEME SETUP
ESCAPE
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RATE SUPERVISION
ESCAPE
MESSAGE [ENTER] for more
CURRENT SUPERVISION
ESCAPE
MESSAGE [ENTER] for more
ZONE COORDINATION
ESCAPE
MESSAGE [ENTER] for more
RECLOSURE 1
ESCAPE
MESSAGE [ENTER] for more
RECLOSURE 2
ESCAPE
MESSAGE [ENTER] for more
RECLOSURE 3
ESCAPE
MESSAGE [ENTER] for more
RECLOSURE 4
ESCAPE
MESSAGE [ENTER] for more
setpoint is set to "Enabled".
750/760 Feeder Management Relay

5.8.8 AUTORECLOSE (760 ONLY)

See page 5–119.
See page 5–122.
See page 5–122.
See page 5–124.
See page 5–126.
A1 STATUS
DEAD TIME BEFORE RECLO-
5 SETPOINTS
AR
GE Multilin