Technical description
2 Protection functions
2.11 Circuit breaker failure stage
CBFP (50BF)
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2.11.
Circuit breaker failure stage CBFP
(50BF)
The circuit breaker failure protection can be used to trip any
upstream circuit breaker (CB), if the fault has not disappeared
within a given time after the initial trip command. A different
output contact of the device must be used for this backup trip.
The operation of the circuit-breaker failure protection (CBFP)
is based on the supervision of the signal to the selected trip
relay and the time the fault remains on after the trip command.
If this time is longer than the operating time of the CBFP
stage, the CBFP stage activates another output relay, which
will remain activated until the primary trip relay resets.
The CBFP stage is supervising all the protection stages using
the same selected trip relay, since it supervises the control
signal of this relay. See chapter 5.4 for details about the output
matrix and the trip relays.
Parameters of the circuit breaker failure stage CBFP (50BF)
Parameter
Value
Unit
Description
Note
Status
-
Blocked
Start
Trip
Current status of the stage
F
F
SCntr
Cumulative start counter
C
TCntr
Cumulative trip counter
C
Force
Off
On
Force flag for status forcing for
test purposes. This is a
common flag for all stages and
output relays, too.
Automatically reset by a 5-
minute timeout.
Set
Cbrelay
1
2
The supervised output relay
*)
.
Relay T1
Relay T2
Set
t>
s
Definite operation time.
Set
For details of setting ranges see chapter 9.2.
Set = An editable parameter (password needed)
C = Can be cleared to zero
F = Editable when force flag is on
*) This setting is used by the circuit breaker condition monitoring, too. See
chapter 3.5.
Recorded values of the latest eight faults
There are detailed information available of the eight latest
faults: Time stamp and elapsed delay.
