11.3.2.5 Control of the auto-reclosing open time for shot 1
Up to four different time settings can be used for the first shot, and one extension time.
There are separate settings for single- and three-phase auto-reclosing open time, t1 1Ph,
t1 3Ph. If no particular input signal is applied, and an autoreclosing program with single-
phase reclosing is selected, the auto-reclosing open time t1 1Ph will be used. If input
signal TR3P is activated in connection with start, the auto-reclosing open time for three-
phase reclosing is used.
An auto-reclosing open time extension delay, tExtended t1, can be added to the normal
shot 1 delay. It is intended to come into use if the communication channel for permissive
line protection is lost. In such a case there can be a significant time difference in fault
clearance at the two ends of the line. A longer “auto-reclosing open time” can then be
useful. This extension time is controlled by setting parameter Extended t1 = Disabled and
the input PLCLOST.
11.3.2.6 Long trip signal
In normal circumstances the trip command resets quickly due to fault clearing. The user
can set a maximum trip pulse duration tTrip. When trip signals are longer, the auto-
reclosing open time is extended by tExtended t1. If Extended t1 = Disabled, a long trip
signal interrupts the reclosing sequence in the same way as a signal to input INHIBIT.
11.3.2.7 Reclosing programs
The maximum number of reclosing shots in an auto-reclosing cycle is selected by the
setting parameter NoOfShots. The type of reclosing used at the first reclosing shot is set by
parameter FirstShot. The first alternative is three-phase reclosing. The other alternatives
include some single-phase or two-phase reclosing. Usually there is no two-phase tripping
arranged, and then there will be no two-phase reclosing.
The decision is also made in the tripping function block (TR) where the setting 3Ph,1/3Ph
is selected.
11.3.2.8 FirstShot=3ph (normal setting for a single 3 phase shot)
3-phase reclosing, one to five shots according to setting NoOfShots. The output three-
phase trip PREP3P is always set (high). A trip operation is made as a three-phase trip at
all types of fault. The reclosing is as a three-phase Reclosing as in mode 1/3ph described
below. All signals, blockings, inhibits, timers, requirements etc. are the same as for
FirstShot=1/3ph .
1MRK 506 334-UUS A Section 11
Control
323
Application manual
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