9328900990 Rev L BE1-951 Application 8-43
Table 8-24. BACKUP Virtual Output Logic
State Labels
Output Purpose Description Label
True False
VOA
(OUTA)
Alarm Output Contact.
Alarm contact closes/opens
(refer to style number)
automatically when relay
trouble alarm occurs.
ALARM ACTIVE NORMAL
BESTlogic Expression: VOA=0
VO1
(OUT1)
Bus Breaker Trip.
Trip for BACKUP breaker
virtual control switch trip OR for
51 trip when in Normal mode.
BKR_TRIP TRIP NORMAL
BESTlogic Expression: VO1=101T+VO8+BFPU
VO2
(OUT2)
Bus Breaker Close.
Close breaker when virtual
breaker control switch is
operated to close.
BKR_CLOSE CLOSE NORMAL
BESTlogic Expression: VO2=101C
VO3
(OUT3)
Feeder Relay Out of
Service.
Signals a relay monitoring the
bus source and using BUS
logic that a feeder relay is out
of service (indicated by open
contact from feeder relays).
BACKUPMODE BACKUP NORMAL
BESTlogic Expression: VO3=/IN2
VO4
(OUT4)
Bus Fault Trip (86B).
Trip bus breaker via lockout for
bus faults (50T with 18-20
cycles delay).
BUS_TRIP TRIP NORMAL
BESTlogic Expression: VO4=VO9
VO5
(OUT5)
Breaker Failure Trip.
Trip backup if breaker
protection times out.
BKR_FAIL TRIP NORMAL
BESTlogic Expression: VO5=BFT
VO6 N/A N/A VO6 TRUE FALSE
BESTlogic Expression: VO6=0
VO7 N/A N/A VO7 TRUE FALSE
BESTlogic Expression: VO7=0
VO8 Time Overcurrent Trip.
TRUE when any time
overcurrent element trips.
51_TRIP TRIP NORMAL
BESTlogic Expression: VO8=51PT+51NT+51QT
VO9
Instantaneous
Overcurrent Trip.
TRUE when any instantaneous
overcurrent element trips.
50_TRIP TRIP NORMAL
BESTlogic Expression: VO9=50TPT+50TNT+50TQT
VO10 Breaker Failure Initiate.
Initiate breaker failure timing
when protective trip expression
is TRUE or when external
initiate contact is sensed and
any of the fault detectors is
picked up.
SUPV-BFI BFI-INI NORMAL
BESTlogic Expression: VO10=VO11+IN3*150TNPU+IN3*150TNPU+IN3*150TQPU
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