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174
Automatic reclosing function (AR)
•
Number of AR attempts
•
AR programs
•
Open times for different AR attempts
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The mode of operation can be selected by setting the parameter Operation to ON, OFF
or Stand-by. ON activates automatic reclosing. OFF deactivates the auto-recloser.
Stand-by enables On and Off operation via input signal pulses.
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The automatic operation of the auto-reclosing function is controlled by the parameter
2SHUDWLRQ and the input signals as described above. When it is on, the AR01-SETON
output is high (active). See Function block diagrams.
The auto-reclosing function is activated at a protection trip by the AR01-START input
signal. At repeated trips, this signal is activated again to make the reclosing program
continue.
There are a number of conditions for the start to be accepted and a new cycle started.
After these checks, the start signal is latched in and the 6WDUWHG state signal is activated.
It can be interrupted by certain events.
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The purpose of this function is to adapt the length of the AR Open time to the possibility
of non-simultaneous tripping at the two line ends. If a permissive communication
scheme is used and the permissive communication channel (for example, PLC, power-
line carrier) is out of service at the fault, there is a risk of sequential non-simultaneous
tripping. To ensure a sufficient line dead time, the AR open time is extended by 0.4 s.
The input signal AR01-PLCLOST is checked at tripping. See Function block diagrams.
Select this function (or not) by setting the Extended t1 parameter to On (or Off).
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During normal circumstances, the trip command resets quickly due to fault clearing.
The user can set a maximum trip pulse duration by tTrip. At a longer trip signal, the AR
open dead time is extended by Extend_t1. If the Extended t1 = Off, a long trip signal
interrupts the reclosing sequence in the same way as AR01-INHIBIT.
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The reclosing program can be performed with up to maximum four reclosing attempts
(shots), selectable with the NoOfReclosing parameter.
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