Functions
2.22 Circuit Breaker Failure Protection
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
400
Figure 2-187 Creation of signal "CB ≥ any pole closed"
If an internal protection function or an external protection device trips without current flow, the circuit breaker
failure protection is initiated by the internal input „Start internal w/o I“, if the trip signal comes from the internal
voltage protection or frequency protection, or by the external input „>BF Start w/o I“. In this case the start
signal is maintained until the circuit breaker is reported to be open by the auxiliary contact criterion.
Initiation can be blocked via the binary input „>BLOCK BkrFail“ (e.g. during test of the feeder protection
relay).
Figure 2-188 Breaker failure protection with common phase initiation
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