Functions
6-259
7SA6 Manual
C53000-G1176-C156-2
Circuit Breaker
Pole Discrepancy
Supervision
The pole discrepancy supervision has the task to detect discrepancies in the position
of the three circuit breaker poles. Under steady-state conditions, either all three poles
of the breaker must be closed, or all three poles must be open. Discrepancy is permit-
ted only for a short time interval during a single-pole automatic reclose cycle.
The scheme functionality is shown in Figure 6-135. The signals which are processed
here are the same as those used for the breaker failure protection. The pole discrep-
ancy condition is established when at least one pole is closed (“CB any pole closed”)
and at the same time not all poles are closed (“CB any pole open”).
Additionally, the current criteria (from Figure 6-122) are processed. Pole discrepancy
can only be detected when current is not flowing through all three poles (<3), i.e.
through only one or two poles. When current is flowing through all three poles, all three
poles must be closed even if the breaker auxiliary contacts indicate a different status.
If pole discrepancy is detected, this is annunciated by a fault detection signal. This sig-
nal identifies the pole which was open before the trip command of the pole discrepan-
cy supervision occurred.
Figure 6-135 Function block diagram of pole discrepancy supervision
6.18.2 Applying the Function Parameter Settings
General
The breaker failure protection and its ancillary functions (end fault protection, pole dis-
crepancy supervision) can only operate if they were configured as
enabled
during
setting of the scope of functions (see Section 5.1, address
139
).
Breaker Failure
Protection
The complete breaker failure protection including its ancillary functions is switched Off
or On under address
3901
FCT BreakerFail
.
The current threshold
I> BF
(address
3902
) should be selected such that the protec-
tion will operate with the smallest expected short-circuit current. To ensure this, the
value should be 10 % less than the minimum anticipated fault current. On the other
hand, the value should not be set lower than necessary.
3932
T-PoleDiscrep.
BF CBdiscr TRIP
<3
L2>
L3>
L1>
T
&
&
(f
ro
m
F
ig
6
-12
2)
&
&
BF CBdiscr L1
BF CBdiscr L3
FNo 1500
FNo 1499
FNo 1498
FNo 1497
0
BF CBdiscr L2
CB any pole closed
CB any pole open
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 ...