Siemens siprotec 7SD5, User Manual

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2.20 Circuit Breaker Failure Protection
371
7SD5 Manual
C53000-G1176-C169-1
Pole Discrepancy
Supervision The pole discrepancy supervision can be switched
ON
or
OFF
independently at
address
3931 PoleDiscrepancy
. It is only useful if the breaker poles can be oper-
ated individually. It avoids that only one or two poles of the local breaker are open
during steady state. 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
) determines how long a breaker
pole discrepancy condition of the feeder circuit breaker, i.e. only one or two poles
open, may be present before the pole discrepancy supervision issues a three-pole trip
command. This time must clearly be longer than the duration of a single-pole automat-
ic reclose cycle. The time should be less than the permissible duration of an unbal-
anced load condition which is caused by the unsymmetrical position of the circuit
breaker poles. Conventional values are 2 s to 5 s.
2.20.3 Settings
The table indicates region-specific presettings. Column C (configuration) indicates the
corresponding secondary nominal current of the current transformer.
Addr. Parameter C Setting Options Default Setting Comments
3901 FCT BreakerFail ON
OFF ON Breaker Failure Protection
is
3902 I> BF 1A 0.05 .. 20.00 A 0.10 A Pick-up threshold I>
5A 0.25 .. 100.00 A 0.50 A
3903 1p-RETRIP (T1) NO
YES YES 1pole retrip with stage T1
(local trip)
3904 T1-1pole 0.00 .. 30.00 sec;
∞
0.00 sec T1, Delay after 1pole start
(local trip)
3905 T1-3pole 0.00 .. 30.00 sec;
∞
0.00 sec T1, Delay after 3pole start
(local trip)
3906 T2 0.00 .. 30.00 sec;
∞
0.15 sec T2, Delay of 2nd stage
(busbar trip)
3907 T3-BkrDefective 0.00 .. 30.00 sec;
∞
0.00 sec T3, Delay for start with de-
fective bkr.
3908 Trip BkrDefect. NO
with T1-trip
with T2-trip
w/ T1/T2-trip NO Trip output selection with
defective bkr
3909 Chk BRK CONTACT NO
YES YES Check Breaker contacts
3921 End Flt. stage ON
OFF OFF End fault stage is
3922 T-EndFault 0.00 .. 30.00 sec;
∞
2.00 sec Trip delay of end fault
stage
3931 PoleDiscrepancy ON
OFF OFF Pole Discrepancy supervi-
sion
3932 T-PoleDiscrep. 0.00 .. 30.00 sec;
∞
2.00 sec Trip delay with pole dis-
crepancy
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