Siemens siprotec 7SA522, User Manual

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Functions
6-210
7SA522 Manual
C53000-G1176-C119-2
Figure 6-110 Function block diagram of end fault protection
Circuit breaker pole
discrepancy super-
vision 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 6-111. 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 (“any pole closed”) and
at the same time not all poles are closed (“any pole open”).
Additionally, the current criteria (from Figure 6-99) 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 6-111 Function block diagram of pole discrepancy supervision
&
3922 T-ENDFault
BF EndFlt TRIP
≥
1 pole closed
> 1
L2>
L3>
L1>
&
T
BF Start
(fr
o
m
F
ig
6-
99)
FNo 1495
FNo 1461
0
3932
T-PoleDiscrep.
BF CBdiscr TRIP
≥
1 pole closed
<3
L2>
L3>
L1>
T
&
≥
1 pole open
&
(f
ro
m F
ig
6-9
9
)
&
&
BF CBdiscr L1
BF CBdiscr L3
FNo 1500
FNo 1499
FNo 1498
FNo 1497
0
BF CBdiscr L2