Functions
2.6 Circuit breaker failure protection (optional)
SIPROTEC, 7VK61, Manual
C53000-G1176-C159-3, Release date 05.2009
127
Note
If the breaker failure protection is to perform a single-pole TRIP repetition, the time set for the AR, address
3408
T-Start MONITOR
, has to be longer than the time set for address
3903
1p-RETRIP (T1)
to prevent
3-pole coupling by the AR before
T1
expires.
To prevent AR after
„BF T2-TRIP(bus)“
, the time
3408
T-Start MONITOR
can be set to expire together
with
T2
.
Figure 2-43
Time sequence example for normal clearance of a fault, and with circuit breaker failure, using
two-stage breaker failure protection
Single-stage breaker failure protection
With single-stage operation, the adjacent circuit breakers (i.e. the breakers of the busbar zone and, if applica-
ble, the breaker at the remote end) are tripped after a delay time
T2
(address
3906
) following initiation, should
the fault not have been cleared within this time.
The timers
T1-1pole
(address
3904
) and
T1-3pole
(address
3905
) are then set to
∞
since they are not
needed.
But you may use the T1 timers for single-stage protection if you wish to utilise the facility of setting different
delay times after single-pole trip and three-pole trip of the feeder protection. In this case set
T1-1pole
(ad-
dress
3904
) and
T1-3pole
(address
3905
) separately, but address
3903
1p-RETRIP (T1)
to
NO
to avoid
a single-pole trip command to the busbar. Set
T2
(address
3906
) to
∞
or equal to
T1-3pole
(address
3905
).
Be sure that the correct trip commands are assigned to the desired trip relay(s).
The delay time is determined from the maximum operating time of the feeder circuit breaker, the reset time of
the current detectors of the breaker failure protection, plus a safety margin which allows for any tolerance of
the delay timers. The time sequence is illustrated in Figure 2-44. The dropout time for sinusoidal currents is
≤
15 ms. If current transformer saturation is anticipated, the time should be set to 25 ms.
Summary of Contents for Siprotec 7VK61
Page 8: ...Preface SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 8 ...
Page 14: ...Contents SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 14 ...
Page 316: ...Literature SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 316 ...
Page 328: ...Glossary SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 328 ...
