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Functions
Trip Seal-in
(Reclosure
Lock-out)
Breaker Tripping
Alarm Suppression
6-300
When tripping the circuit-breaker with a protection function reclosure must often be
locked until the cause for the protection function operation is found. 7SA6 therefore
provides the integrated reclosure lock-out function.
The lock-out state (" LOCKOUT ") is realized by a RS flipflop which is protected against
auxiliary voltage failure (see Figure 6-153). The RS flipflop will be set via a binary input
" >Lockout SET " (FNo 385 ). With the output alarm " LOCKOUT " (FNo 530 ), if intercon-
nected correspondingly, a reclosure of the circuit-breaker (e.g. for automatic reclos-
ure, manual close signal, synchronization, closing via control) can be blocked. Only
once the cause for the protection operation is known, should the lock-out be reset by
a manual reset via binary input " >Lockout RESET " (FNo 386 ).
FNo 385
>LOCKOUT Set
FNo 386
>LOCKOUT Reset
Figure 6-153 Trip circuit seal-in (reclosure lock-out)
The conditions which cause reclosure lock-out and the control commands which have
to be locked can be set individually. The two inputs and the output can be wired via
the correspondingly allocated binary inputs and outputs or be linked via user-defined
logic functions (CFC).
If, for example, each trip by the protection function should be sealed, then combine the
tripping command " Relay TRIP " (FNo 511 ) with the binary input " >Lockout SET ".
If automatic reclosure is applied, only the final trip of the protection function should es-
tablish closing lock-out. Then combine the output alarm " Definitive TRIP " (FNo
536 ) with the lock-out input " >Lockout SET ", so that the lock-out function is not es-
tablished when an automatic reclosure is still expected to come.
In the most simple case the output alarm " LOCKOUT " (FNo 530) can be allocated to
the output which trips the circuit-breaker without creating further links. Then the trip-
ping command is sealed until the lock-out is reset via the binary reset input. Naturally
it has to be ensured in advance that the close coil at the circuit breaker — as is usually
done — is locked as long as a tripping command is maintained.
The output alarm " LOCKOUT " can also be applied to interlock certain closing com-
mands (externally or via CFC), e.g. by combining the output alarm with the binary input
" >Close Cmd. Blk " (FNo 357 ) or by connecting the inverted alarm with the bay in-
terlocking of the feeder.
The reset input " >Lockout RESET " (FNo 386 ) resets the interlocking state. This input
is initiated by an external device which is protected against unauthorized or uninten-
tional operation. The lock-out state can also be reset by internal sources, e.g. a func-
tion key, operation of the device or using DIGSI
For each case please make sure the corresponding logical combinations, security
measures, etc. are taken into account for the routing of the binary inputs and outputs
(Section 5.2) and are also considered for the setting of user-defined logic functions
(Section 5.3), if necessary.
While on feeder without automatic reclosure every trip command by a protection func-
tion is final, it is desirable, when using automatic reclosure, to prevent the operation
detector of the circuit-breaker (intermediate contact on the breaker) from sending an
alarm if the trip of the breaker is not final (Figure 6-154).
FNo 530
S
Q
LOCKOUT
R
®
4 on a PC.
C53000-G1176-C156-2
7SA6 Manual
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