Siemens siprotec 7SA522 User Manual page 356

Functions
Circuit breaker not
operational
Transfer trip to the
remote end circuit
breaker
6-208
For the first time stage, different time delays can be selected for a single-pole trip and
three-pole trip by the feeder protection. Additionally, you can select (parameter S
5(75,3 7 ) whether this repeated trip should be single-pole or three-pole.
Start only L1
> 1
Start only L2
Start only L3
Start L123
Figure 6-107 Two-stage breaker failure protection with phase segregated initiation — one
phase
There may be cases when it is immediately apparent that the circuit breaker associat-
ed 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
"!&% GHIHFW" of the 7SA522. 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 6-108). Thus, the adjacent circuit breakers (bus-bar) are tripped imme-
diately in case the feeder circuit breaker is not operational.
FNo 1461
(all initiation
conditions BF Start
Fig 6-101/6-
104)
FNo 378
>CB faulty
Figure 6-108 Circuit breaker not operational
The 7SA522 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).
"(# 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-C119-2
7SA522 Manual