Siemens siprotec 7SA6 User Manual

Functions
6-236 7SA6 Manual
C53000-G1176-C133-1
Figure 6-122 Two-stage breaker failure protection with phase segregated initiation — one
phase
Circuit Breaker not
Operational
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.
Figure 6-123 Circuit breaker not operational
Transfer Trip to the
Remote End Circuit
Breaker
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.
BF T1-TRIP L123
BF T2-TRIP (bus)
(Trip
bus-bar)
Start only L1
Start only L2
Start only L3
Start L123
>
1
7
7
 73ROH
 73ROH
7
 7
>
1
<HV
1R
 S5(75,37
>
1
&
BF T1-TRIP 1pL1
Start only L1
(accordingly for
other phases)
(Trip repetition
feeder breaker)
FNo 1472
FNo 1476
FNo 1494
T0
&
(all initiation
conditions
Fig 6-116/6-119)
 7%NU'HIHFWLYH
>CB faulty
BF TRIP CBdefec
BF Start
FNo 378
FNo 1493
FNo 1461

Siemens siprotec 7SA6 Specifications

General

Brand	Siemens
Model	siprotec 7SA6
Category	Relays
Language	English