Siemens SIPROTEC 4, User Manual

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blocked via binary input (no. 235.2113
>$00 BLK.TDly
). The time delay will not be started as long as the
binary input is active; a trip can thus be initiated. The time delay is started after the binary input has dropped
out and the pickup is still present. It is also possible to bypass the expiration of the time delay by activating
binary input (no. 235.2111
>$00 instant.
). The trip will be launched immediately when the pickup is
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 delay time 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
>$00 Dir.TRIP
), it will be logically
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
Figure 2-114 .
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 7006
50BF PICKUP
(Power System Data 1) has been exceeded.
•
Automatic reclosing (AR):
The AR cannot be started directly. In order to interact with the AR, the trip command of the flexible func-
tion needs be linked in CFC to binary input no. 2716
>Start 79 Ph
or no. 2715
>Start 79 Gnd
.
Using an operating time requires the pickup of the flexible function to be linked to binary input no. 2711
>79 Start
.
•
Fuse-Failure-Monitor (see description at “Blocking Functions”).
•
Inrush restraint:
Direct interaction with the inrush restraint is not possible. In order to block a flexible function by the
inrush restraint, the blocking must be carried out in CFC. The flexible function provides three binary
inputs for blocking trip commands selectively for each phase (no. 235.2115 to 235.2117). They have to
be linked with the phase-selective indications for detecting the inrush (no. 1840 to 1842). Activating a
crossblock function requires the phase-selective inrush indications to be logically combined with the
binary input for blocking the function trip command (no. 235.2114
>$00 BLK.TRIP
). The flexible func-
tion also needs to be delayed by at least 20 ms to make sure that the inrush restraint picks up before the
flexible function.
•
Entire relay logic:
The pickup signal of the flexible function is added to the general device pickup, the trip signal is added to
the general device trip (see also Section
2.24 Function Logic ). All functions associated with general
device pickup and tripping are thus also applied to the flexible function.
After the picked up element has dropped out, the trip signals of the flexible protection functions are held
up at least for the specified minimum trip command time 210
TMin TRIP CMD
.
Setting Notes
The setting of the functional scope determines the number of flexible protection functions to be used (see
Section
2.1.1 Functional Scope ). If a flexible function in the functional scope is disabled (by removing the
2.19.2
Functions
2.19 Flexible Protection Functions
SIPROTEC 4, 7SJ62/64, Manual 273
C53000-G1140-C207-8, Edition 08.2016