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2.12 Automatic Reclosure Function
131
7ST6 Manual
E50417-G1176-C251-A3
2.12.2 Setting Notes
General
If no reclosure is required on the feeder to which the 7ST6 overhead contact line pro-
tection is applied, e.g. for transformers, the auto reclose function must be removed
during configuration of the device (address
133
, see Section 2.1.1.2). The auto
reclose function is then totally disabled, i.e. the automatic reclosure is not processed
in the 7ST6. No signals regarding the auto reclose function are generated, and the
binary inputs for the auto reclose function are ignored. All parameters for setting the
auto reclose function are inaccessible and of no significance.
Up to 8 reclosure attempts are allowed with the integrated auto reclose function in the
7ST6. The number of reclosure attempts is specified in address
3402
No.Recl.
.
Whereas the settings in the addresses
3401
to
3434
are common to all reclosure
cycles, the individual settings for the first cycle are made from address
3430
onwards.
For the second and all higher cycles, the parameters from address
3440
are valid.
The auto reclose function can be turned
ON
or
OFF
in address
3401
AUTO RECLOSE
.
A prerequisite for automatic reclosure taking place after a trip due to a short-circuit is
that the circuit breaker is ready for at least one TRIP-CLOSE-TRIP cycle at the time
the automatic reclosure circuit is started, i.e. at the time of the first trip command. The
readiness of the circuit breaker is signalled to the device through the binary input
„>CB
Ready“
(FNo. 2730). If no such signal is available, leave the setting in address
3415
CB? 1.TRIP
=
NO
(default setting) because no automatic reclosure would be possible
at all otherwise. If circuit breaker interrogation is possible, set
3415
CB? 1.TRIP
=
YES
.
The circuit breaker ready state can also be interrogated by the 7ST6 prior to every re-
closure. The monitoring time
CB TIME OUT
is set in address
3417
. The monitoring
time
CB TIME OUT
is the same for all reclosure cycles. It starts as soon as the CB
indicates the "not ready" state. The time is set slightly longer than the recovery time of
the circuit breaker after a TRIP-CLOSE-TRIP cycle. If the circuit breaker is not ready
again by the time this timer expires, no reclosure takes place, the automatic reclosure
function is blocked dynamically.
Waiting for the circuit breaker to be ready can lead to an increase of the dead times.
Interrogation of a synchronization check (if used) can also delay reclosure. To avoid
uncontrolled prolongation it is possible to set a maximum prolongation of the dead
time in this case in address
3421
T-DEAD EXT.
. This prolongation is unlimited if the
setting
∞
is applied. This parameter can only be altered with DIGSI® under „ Display-
ing Additional Settings“. Remember that longer dead times are only permissible after
three-pole tripping when no stability problems arise or when a synchro-check takes
place before reclosure.
The blocking time
TIME RESTRAINT
(address
3420
) defines the time that must
elapse, after a successful reclosing attempt, before the auto reclose function is reset.
Re-tripping of a protection function within this time initiates the next reclose cycle in
the event of multiple reclosure; if no further reclosure is permitted, the last reclosure
is treated as unsuccessful. The reclaim time must therefore be longer than the longest
response time of a protective function which can start the automatic reclosure circuit.
A few seconds are generally sufficient. In areas with frequent thunderstorms or
storms, a shorter reclaim time may be necessary to avoid feeder lockout due to se-
quential lightning strikes or flashovers.
A longer reclaim time should be chosen where circuit breaker supervision is not pos-
sible (see above) during multiple reclosures, e.g. because of missing auxiliary con-
tacts and information on the circuit breaker ready status. In this case, the reclaim time
should be longer than the time required for the circuit breaker mechanism to be ready.
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Содержание SIPROTEC 7ST6
Страница 14: ...Contents 14 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 24: ...1 Introduction 24 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 254: ...3 Mounting and Commissioning 254 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 288: ...4 Technical Data 288 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 340: ...A Appendix 340 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 342: ...Literature 342 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 354: ...Index 354 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 355: ...Index 355 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 356: ...Index 356 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...