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Functions
2.15 Flexible Protection Functions
present and the binary input has been activated. The trip command can be blocked via binary inputs (no.
235.2115
>$00 BL.TripA ) and (no. 235.2114 >$00 BLK.TRIP ). The phase-selective blocking of the trip
command is required for interaction with the inrush restraint (see "Interaction with other functions"). The
function's dropout ratio can be set. If the threshold (>-element) is undershot after the pickup, the dropout
time delay will be started. The pickup is maintained during that time, a started trip time delay continues to
count down. If the trip time delay has elapsed while the dropout time delay is still during, the trip command
will only be given if the current threshold is exceeded. The element will only drop out when the dropout time
delay has elapsed. If the time is set to zero, the dropout will be initiated immediately once the threshold is
undershot.
External Trip Commands
The logic diagram does not explicitly depict the external trip commands since their functionality is analogous.
If the binary input is activated for external trip commands (no. 235.2112
treated as threshold overshooting, i.e. once it has been activated, the pickup time delay is started. If the
pickup time delay is set to zero, the pickup condition will be reported immediately starting the trip time delay.
Otherwise, the logic is the same as depicted in
Interaction with Other Functions
The flexible protection functions interact with a number of other functions such as the
•
Breaker failure protection:
The breaker failure protection is started automatically if the function initiates a trip. The trip will,
however, only take place if the current criterion is met at this time, i.e. the set minimum current
threshold 3902 50BF PICKUP has been exceeded.
•
With the Automatic Reclosure Function (AR):
The AR cannot be started directly. To cooperate with AR, the trip command of the flexible function must
be linked with the binary input No. 2716
flexible function must additionally be linked to the binary input No. 2711
•
Fuse-Failure-Monitor (see description at "Blocking Functions").
•
With inrush restraint:
A direct cooperation with the inrush restraint is not possible. If a flexible function is to be blocked by the
inrush restraint, this blocking must be configured via CFC. Furthermore, please note that the flexible
function must be delayed by at least 20 ms to enable the inrush restraint to pick up reliably before the
flexible function.
•
With the overall device logic:
The pickup indication of the flexible function is included in the general pickup, and the tripping in the
general trip. All functionalities associated with the general pickup and general trip therefore also apply to
the flexible function.
Setting Notes
2.15.2
The setting of the functional scope determines the number of flexible protection functions to be used (see
Section
2.1.1 Functional
checkmark), this will result in losing all settings and configurations of this function or its settings will be reset
to their default settings.
General
In the DIGSI setting dialog "General", parameter In the DIGSI setting dialog „General", parameter FLEXIBLE
FUNC. can be set to OFF, ON or Alarm Only. If the function is enabled in operational mode Alarm Only, no
faults are recorded, no „Effective"-indication is generated, no trip command issued and neither will the circuit-
breaker protection be affected. Therefore, this operational mode is preferred when a flexible function is not
required to operate as a protection function. Furthermore, the OPERRAT. MODE can be configured.
170
Figure
>79 TRIP 3p via CFC. To use an action time, the pickup of the
Scope). If a flexible function in the functional scope is disabled (by removing the
>$00 Dir.TRIP ), it will be logically
2-77.
>79 Start .
E50417-G1100-C474-A2, Edition 02.2018
SIPROTEC 4, 7SD80, Manual
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