3 Mounting and Commissioning
306
7SD610 Manual
C53000-G1176-C145-4
External Initiation
Conditions
If the breaker failure protection can also be started by external protection devices, the
external start conditions are checked. Depending on the device version and the setting
of the breaker failure protection, single-pole or three-pole trip are possible. The pole
discrepancy check of the device or the actual breaker may lead to three-pole tripping
after single-pole tripping. Therefore check first how the parameters of the breaker
failure protection are set. See also Section 2.13.2, addresses 3901 onwards.
In order for the breaker failure protection to be started, a current must flow at least
through the monitored phase and the earth. This may be a secondary injected current.
After every start the indication „BF Start“ (no. 1461) must appear in the spontane-
ous or fault indications.
If only single-pole initiation is possible:
• Start by single-pole trip command of the external protection L1:
Binary input functions „>BF Start L1“ and, if necessary, „>BF release“ (in
spontaneous or fault indications). Trip command (depending on settings).
• Start by single-pole trip command of the external protection L2:
Binary input functions „>BF Start L2“ and, if necessary, „>BF release“ (in
spontaneous or fault indications). Trip command (depending on settings).
• Start by single-pole trip command of the external protection L3:
Binary input functions „>BF Start L3“ and, if necessary, „>BF release“ (in
spontaneous or fault indications). Trip command (dependent on settings).
• Start by three-pole trip command of the external protection via all three binary inputs
L1, L2 and L3:
Binary input functions „>BF Start L1“, „>BF Start L2“ and „>BF Start
L3“ and, if necessary, „>BF release“ (in spontaneous or fault indications).
Three-pole trip command.
For three-pole initiation:
• Start by three-pole trip command of the external protection :
Binary input functions „>BF Start 3pole“ and, if necessary, „>BF release“
(in spontaneous or fault indications). Trip command (dependent on settings).
Switch off test current.
If start is possible without current flow:
• Starting by trip command of the external protection without current flow:
Binary input functions „>BF Start w/o I“ and, if necessary, „>BF release“
(in spontaneous or fault indications). Trip command (dependent on settings).
Busbar Tripping The most important thing is the check of the correct distribution of the trip commands
to the adjacent circuit breakers in case of breaker failure.
The adjacent circuit breakers are those of all feeders which must be tripped in order
to ensure interruption of the fault current should the local breaker fail. These are there-
fore the circuit breakers of all feeders which feed the busbar or busbar section to which
the feeder with the fault is connected.
A general detailed test guide cannot be specified because the layout of the adjacent
circuit breakers largely depends on the system topology.
In particular with multiple busbars the trip distribution logic for the surrounding circuit
breakers must be checked. Here check for every busbar section that all circuit break-
ers which are connected to the same busbar section as the feeder circuit breaker
under observation are tripped, and no other breakers.
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