5-106 750/760 Feeder Management Relay GE Multilin
5.8 S7 CONTROL 5 SETPOINTS
5
5.8.6 UNDERFREQUENCY RESTORATION
PATH: SETPOINTS ÖØ S7 CONTROL ÖØ UNDERFREQ RESTORE
This scheme is initiated by a trip of either the Bus Underfrequency elements. After the feeder breaker has been tripped, it
will display the UFreq Restore Init and operate any programmed output relays. Once initiated it will monitor the bus voltage
level and frequency, and send a close command to the Close Relay when the voltage on the phase A input has risen above
the programmed minimum level and frequency for a selected time interval. The scheme is equipped with an incomplete
sequence timer, so it will not remain initiated for an indeterminate time, but will automatically reset if the voltage does not
recover during the programmed interval. Initiation of the scheme can be canceled by a reset command. Cancellation of a
previous initiation is only effective if the voltage and frequency are above the restoration thresholds. A “Block Restoration”
logic input is available to prevent both initiation and operation. It is recommended that if automatic underfrequency restora-
tion is to be used, that the cold load pickup feature is also enabled, to prevent the breaker from tripping shortly after it is
automatically closed.
UNDERFREQ RESTORE
[ENTER] for more
UNDERFREQ RESTORE
FUNCTION: Disabled
Range: Disabled, Alarm, Latched Alarm, Control
UNDERFREQ RESTORE
RELAYS (3-7): -----
Range: Any combination of 3 to 7 Auxiliary relays
UNDERFREQ RESTORE
MIN VOLTS: 0.90 x VT
Range: 0.00 to 1.25 x VT in steps of 0.01
UNDERFREQ RESTORE
MIN FREQ: 59.90 Hz
Range: 20.00 to 65.00 Hz in steps of 0.01
UNDERFREQ RESTORE
DELAY: 10 s
Range: 0 to 10000 s in steps of 1
INCOMPLETE SEQUENCE
TIME: 100 min
Range: 1 to 10000 min. in steps of 1
ENTER
ESCAPE
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Courtesy of NationalSwitchgear.com
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