Settings - Siemens SIPROTEC 4 7VK61 Manual

Functions
2.6 Circuit breaker failure protection (optional)
Circuit breaker not operational
These delays are not necessary if the control circuit of the local circuit breaker is faulted (e.g. control voltage
failure or air pressure failure) since it is apparent that the circuit breaker is not capable of clearing the fault. If
the relay is informed about this disturbance (via the binary input
(busbar and remote end if applicable) are tripped after the time T3-BkrDefective (address 3907) which is
usually set to 0.
Address 3908 Trip BkrDefect. determines to which output the trip command is routed in the event that
the circuit breaker is not operational when a feeder protection trip occurs. Select that output which is used to
trip the adjacent circuit breakers (bus-bar trip).
End fault protection
The end fault protection can be switched in address 3921 End Flt. stage separately to ON- or OFF. An end
fault is a short-circuit between the circuit breaker and the current transformer set of the feeder. The end fault
protection presumes that the device is informed about the circuit breaker position via circuit breaker auxiliary
contacts connected to binary inputs.
If, during an end fault, the circuit breaker is tripped by a reverse stage of the feeder protection or by the
busbar protection (the fault is a busbar fault as determined from the location of the current transformers), the
fault current will continue to flow, because the fault is fed from the remote end of the feeder circuit.
The time T-EndFault (address 3922) is started when, during the time of pickup condition of the feeder
protection, the circuit breaker auxiliary contacts indicate open poles and, at the same time, current flow is still
detected (address 3902). The trip command of the end fault protection is intended for the transmission of an
intertrip signal to the remote end circuit breaker.
Thus, the delay time must be set so that it can bridge out short transient apparent end fault conditions which
may occur during switching of the circuit breaker.
Pole discrepancy supervision
In address 3931 PoleDiscrepancy (pole discrepancy protection), the pole discrepancy supervision can be
switched separately ON- or OFF. It is only useful if the circuit breaker poles can be operated individually. It
avoids that only one or two poles of the local circuit breaker are open continuously. It has to be provided that
either the auxiliary contacts of each pole or the series connection of the NO auxiliary contacts and the series
connection of the NC auxiliary contacts are connected to the device's binary inputs. If these conditions are not
fulfilled, switch address 3931 OFF.
The delay time T-PoleDiscrep. (address 3932) indicates how long a circuit breaker pole discrepancy condi-
tion of the feeder circuit breaker, i.e. only one or two poles open, may be present before the pole discrepancy
supervision issues a 3-pole trip command. This time must be clearly longer than the duration of a 1-pole auto-
matic reclose cycle. The time should be less than the permissible duration of an unbalanced load condition
which is caused by the unsymmetrical position of the circuit breaker poles. Standard durations are between 2 s
and 5 s.

Settings

2.6.3
The table indicates region-specific presettings. Column C (configuration) indicates the corresponding secon-
dary nominal current of the current transformer.
Addr. Parameter
3901 FCT BreakerFail
3902 I> BF
3903 1p-RETRIP (T1)
3904 T1-1pole
128
C Setting Options
ON
OFF
1A 0.05 .. 20.00 A
5A 0.25 .. 100.00 A
NO
YES
0.00 .. 30.00 sec
>CB faulty , the adjacent circuit breakers
Default Setting Comments
ON Breaker Failure Protection
0.10 A Pick-up threshold I>
0.50 A
YES 1pole retrip with stage T1
(local trip)
0.00 sec T1, Delay after 1pole start
(local trip)
SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018