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Circuit Breaker
Auxiliary Contacts
External Start
Conditions
Busbar tripping
7SA6 Manual
C53000-G1176-C156-2
The trip command of the tested Distance Protection is made ineffective so that the lo-
cal breaker can be tripped only by the breaker failure protection function of 7SA6.
Although the following lists do not claim to be complete it may also contain points
which are to be ignored in the current application.
If the circuit breaker auxiliary contacts are connected to the device, these provide an
essential input to the functionality of the breaker failure protection. Make sure the
correct assignment has been checked (Section 8.3.3).
If the breaker failure protection can also be started by external protection devices, the
external start conditions should be checked. Single-pole or three-pole tripping is pos-
sible depending on the setting of the breaker failure protection. The pole discrepancy
check of the device or the breaker may itself lead to three-pole tripping after single-
pole tripping. Therefore check first how the parameters of the breaker failure protec-
tion are set. See Subsection 6.18.2, addresses 3901 onwards.
In order for the breaker failure protection to be started, a current must flow at least via
the monitored phase. This may be a secondary injected current.
After every start, the message " BF Start " (FNo. 1461 ) must appear in the sponta-
neous annunciation list or the trip log.
Only if phase segregated starting possible:
G
single-pole starting by trip command of the external protection in phase L1:
binary input functions " >BF Start L1 " and possibly " >BF release " (in sponta-
neous or fault messages). Trip command depending on configuration.
G
single-pole starting by trip command of the external protection in phase L2:
binary input functions " >BF Start L2 " and possibly " >BF release " (in sponta-
neous or fault messages). Trip command depending on configuration.
G
single-pole starting by trip command of external protection in phase L3:
binary input functions " >BF Start L3 " and possibly " >BF release " (in sponta-
neous or fault messages). Trip command depending on configuration.
G
three-pole starting by trip command of the external protection via all three binary in-
puts L1, L2 and L3:
binary input functions " >BF Start L1 ", " >BF Start L2 " and " >BF Start L3 "
and possibly " >BF release " (in spontaneous or fault messages). Trip command
three-pole.
For common phase starting:
G
three-pole starting by trip command of the external protection:
binary input functions " >BF Start 3pole " and possibly " >BF release " (in spon-
taneous or fault messages. Trip command depending on configuration.
Switch off test current.
If BF start is possible without current flow
G
BF start by trip command of the external protection without current flow:
binary input functions " >BF Start w/o I " and possibly " >BF release " (in spon-
taneous or fault messages). Trip command depending on configuration.
For testing the distribution of the trip commands in the substation in the case of break-
er failures it is important to check that the trip commands to the surrounding circuit
breakers is correct.
Installation and Commissioning
8-57
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