Siemens SIPROTEC 7SD610 Manual page 183

Phase-segregated initiation
Phase segregated initiation of the circuit breaker failure protection is necessary if the circuit breaker poles are
operated individually, e.g. if 1-pole automatic reclosure is used. This is possible if the device is able to trip 1-
pole.
If the circuit breaker failure protection is intended to be initiated by further external protection devices, it is rec-
ommended, for security reasons, to connect two binary inputs to the device. Besides the three trip commands
of the external relay to the binary input „>BF Start L1", „>BF Start L2" and „>BF Start L3" it is
recommended to connect also, for example, the general device pickup to binary input „>BF release". Figure
2-70 shows this connection.
Nevertheless, it is possible to initiate the circuit breaker failure protection in single-channel mode should a sep-
arate release criterion not be available. The binary input „>BF release" must then not be assigned to any
physical input of the device during configuration.
If the external protection device does not provide a general fault detection signal, a general trip signal can be
used instead. Alternatively, the parallel connection of a separate set of trip contacts can produce such a release
signal as shown in Figure 2-71.
Figure 2-70
Figure 2-71
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
Breaker failure protection with phase segregated initiation — example for initiation by
an external protection device with release by a fault detection signal
Breaker failure protection with phase segregated initiation — example for initiation by
an external protection device with release by a separate set of trip contacts
Functions
2.13 Circuit Breaker Failure Protection
183