Functions
6-250
7SA6 Manual
C53000-G1176-C156-2
Figure 6-122 Current flow monitoring with the plausibility currents 3·
I
0
and 3·
I
2
Processing of the
Circuit Breaker
Auxiliary Contacts
The position of the circuit breaker is derived from the central function control of the de-
vice (refer also to Section 6.22.2). Evaluation of the breaker auxiliary contacts is car-
ried out in the breaker failure protection function only when the current flow monitoring
has not picked up. Once the current flow criterion has picked up during the trip signal
from the feeder protection, the circuit breaker is assumed to be open as soon as the
current disappears, even if the associated auxiliary contact does not (yet) indicate that
the circuit breaker has opened (Figure 6-123). This gives preference to the more reli-
able current criterion and avoids overfunctioning due to a defect e.g. in the auxiliary
contact mechanism or circuit. This interlock feature is provided for each individual
phase as well as for three-pole trip.
It is possible to disable the auxiliary contact criterion. If you set the parameter switch
Chk BRK CONTACT
(Figure 6-125 above) to
No
, the breaker failure protection can
only be started when current flow is detected. The position of the auxiliary contacts is
then not evaluated even if the auxiliary contacts are connected to the device.
I>
&
I>
I>
&
&
&
&
&
> 1
> 1
> 1
Current
criterion
I
L1
I
L2
I
L3
> 1
I>
3I
2
I>
3I
0
3902
I> BF
L1>
L2>
L3>
plausi-
bility
Summary of Contents for siprotec 7SA6
Page 2: ...Siemens Aktiengesellschaft Book No C53000 G1176 C156 2 ...
Page 18: ...xviii 7SA6 Manual C53000 G1176 C156 2 ...
Page 32: ...Introduction 1 14 7SA6 Manual C53000 G1176 C156 2 ...
Page 82: ...Hardware and Connections 2 50 7SA6 Manual C53000 G1176 C156 2 ...
Page 119: ...SIPROTEC 4 Devices 4 25 7SA6 Manual C53000 G1176 C156 2 Figure 4 20 CFC Logic example ...
Page 190: ...Configuration 5 62 7SA6 Manual C53000 G1176 C156 2 ...
Page 652: ...Installation and Commissioning 8 78 7SA6 Manual C53000 G1176 C156 2 ...
Page 724: ...Technical Data 10 56 7SA6 Manual C53000 G1176 C156 ...
Page 800: ...Appendix A 76 7SA6 Manual C53000 G1176 C156 2 ...
Page 866: ...Appendix B 66 7SA6 Manual C53000 G1176 C156 2 ...