Siemens SIPROTEC 7UT613 series, Manual, Page: 268 / 638

2 Functions
268
7UT613/63x Manual
C53000-G1176-C160-2
2.17 Circuit Breaker Failure Protection
The circuit breaker failure protection provides rapid back-up fault clearance, in the
event that the assigned circuit breaker fails to respond to a protective relay.
7UT613/63xis equipped with two breaker failure protection functions that can be used
independently from each other and for different locations of the protected object, i.e.
for different circuit breakers. You can also work with different starting criteria (see
below). Allocation of the protective function to the sides or measuring locations and
breakers were done according to Section 2.1.4.
2.17.1 Function Description
General The following information refers to the first breaker failure protection, if not stated oth-
erwise.
Whenever the differential protection or any internal or external fault protection function
of a feeder issues a trip command to the circuit breaker, for example, this is indicated
to the breaker failure protection at the same time (figure 2-107). A timer T–BF in the
breaker failure protection is started. The timer runs as long as a trip command is
present and current continues to flow through the breaker poles.
Figure 2-107 Simplified function diagram of circuit breaker failure protection with current flow
monitoring