Siemens siprotec 7SA6 User Manual page 418

Functions
Circuit Breaker not
Operational
Transfer Trip to the
Remote End Circuit
Breaker
6-236
Start only L1
> 1
Start only L2
Start only L3
Start L123
Figure 6-122 Two-stage breaker failure protection with phase segregated initiation — one
phase
There may be cases when it is immediately apparent that the circuit breaker
associated with a feeder protection relay cannot clear a fault, e.g. when the tripping
voltage or the tripping energy is not available.
In such a case it is not necessary to wait for the response of the feeder circuit breaker.
If provision has been made for the detection of such a condition (e.g. control voltage
monitor or air pressure monitor), the monitor alarm signal can be fed to the binary input
"!&% IDXOW\" of the 7SA6. On occurrence of this alarm and a trip command by the
feeder protection, a separate timer 7%NU'HIHFWLYH, which is normally set to 0, is
started (Figure 6-123). Thus, the adjacent circuit breakers (bus-bar) are tripped
immediately in case the feeder circuit breaker is not operational.
FNo 1461
(all initiation
BF Start
conditions
Fig 6-116/6-119)
FNo 378
>CB faulty
Figure 6-123 Circuit breaker not operational
The 7SA6 has the facility to give an additional intertrip signal to the circuit breaker at
the remote line end in the event that the local feeder circuit breaker fails. For this, a
suitable protection signal transmission link is required (e.g. via communication cable,
power line carrier transmission, radio transmission, or optical fibre transmission).
To realise this intertrip, the desired command — usually the trip command which is
intended to trip the adjacent breakers — is assigned to a binary output of the device.
The contact of this output triggers the transmission device.
"(# U  Q‚yr "(" ƒS@USDQÃU 
<HV
UÃÃÃÃÃÃ
1R
"($ U "Q‚yr
> 1
UÃÃÃÃÃÃ
"(% U!
UÃÃÃÃÃÃ
> 1
"(& U"7x…9rsrp‡v‰r
T
&
(accordingly for
other phases)
FNo 1472
&
BF T1-TRIP 1pL1
Start only L1
(Trip repetition
feeder breaker)
FNo 1476
BF T1-TRIP L123
(Trip
bus-bar)
FNo 1494
BF T2-TRIP (bus)
FNo 1493
0
BF TRIP CBdefec
C53000-G1176-C133-1
7SA6 Manual