A time extension delay, tExtended t1, can be added to the dead time delay for the
first shot. It is intended to come into use if the communication channel for
permissive line protection is lost. In a case like this there can be a significant time
difference in fault clearance at the two line ends, where a longer auto reclosing
dead time can be useful. This time extension is controlled by the setting Extended
t1 = On and the PLCLOST input. If this functionality is used the auto recloser start
must also be allowed from distance protection zone 2 time delayed trip. Time
extension delay is not possible to add to the three-phase high-speed auto reclosing
dead time, t1 3PhHS.
12.2.2.6 Long trip signal
M12391-117 v4
In normal circumstances the auto recloser is started with a protection trip command
which resets quickly due to fault clearing. The user can set a maximum start pulse
duration tLongStartInh. This start pulse duration time is controlled by setting
LongStartInhib.
When start pulse duration signal is longer than set maximum start pulse duration,
the auto reclosing sequence interrupts in the same way as for a signal to the
INHIBIT input.
12.2.2.7 Maximum number of reclosing shots
M12391-120 v7
The maximum number of auto reclosing shots in an auto reclosing cycle is selected
by the setting NoOfShots. A maximum of five shots can be done. The type of auto
reclosing used at the first auto reclosing shot is set by the setting ARMode. The first
alternative is three-phase auto reclosing. The other alternatives include some
single-phase or two-phase auto reclosing. Usually there is no two-phase tripping
arranged, and then there will be no two-phase auto reclosing.
The decision for single- and three-phase trip is also made in the tripping logic
(SMPTTRC) function block where the setting 3 phase, 1ph/3Ph (or 1ph/2ph/3Ph)
is selected.
12.2.2.8
ARMode
=
3ph,
(normal setting for a three-phase shot)
M12391-124 v5
Three-phase auto reclosing, one to five shots according to the NoOfShots setting.
The prepare three-phase trip PREP3P output is always set (high). A trip operation
is made as a three-phase trip for all type of faults. The auto reclosing is as a three-
phase auto reclosing as in mode 1/2/3ph described below. All signals, blockings,
inhibits, timers, requirements and so on, are the same as in the example described
below.
12.2.2.9
ARMode
=
1/2/3ph
M12391-127 v8
Single-phase, two-phase or three-phase auto reclosing first shot, followed by 3-
phase auto reclosing shots, if selected. Here, the auto recloser is assumed to be
"On" and "Ready". The circuit breaker is closed and the operation gear ready
1MRK 505 393-UEN B Section 12
Control
Line differential protection RED650 2.2 IEC 235
Application manual
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