There are several counters within the function. One for each shot and type of fault
and one overall counter for total number of circuit breaker closing commands. All
counters can be reset to zero using either the HMI command or the RSTCOUNT
input or by an IEC 61850 command.
The circuit breaker closing command, CLOSECB output is a pulse with settable
duration by setting tPulse. For circuit breakers without anti-pumping function,
close pulse cutting can be used. This is controlled by the setting CutPulse. In case
of a new auto recloser start pulse, the breaker closing command pulse is cut
(interrupted). The minimum duration of the closing pulse is always 50ms.
The prepare three-phase trip, PREP3P output is usually connected to the trip
function SMPPTRC to force the coming trip to be three-phase. If the auto recloser
cannot make a single-phase or two-phase reclosing, the start from the trip function
should be three-phase.
The permit single-phase trip, PERMIT1P output is the inverse of the PREP3P
output. It can be connected to a binary output relay for connection to external
protection or trip relays. In case of a total loss of auxiliary power, the output relay
drops and does not allow single-phase trip.
The setting Follow CB can be used to prevent close command to be issued when
dead time has expired and circuit breaker is already closed (e.g. by manual close
command). If a new start is received after the dead time expiration the auto recloser
will advance to next shot.
If input SKIPHS is activated, and simultaneously STARTHS input is initiated then
actually normal three-phase shot one with dead time "t1 3Ph" will be started.
The ZONESTEP input is used when coordination between local auto reclosers and
down stream auto reclosers is needed. If function is in "ready" status and this input
is activated the auto recloser increases its actual shot number by one and enters
directly the “reclaim time” status for shot one. If a start is received during the
reclaim time, the function will proceed with the next shot (e.g. starting dead time
for shot two). Every new pulse on the ZONESTEP input will further increase the
shot number. Note that ZONESTEP input will have such effect only if local start
signal was not activated, as shown in Figure
157. The setting NoOfShots limits of
course the maximum number of available shots. This functionality is controlled by
the setting ZoneSeqCoord.
By activating the THOLHOLD input the auto recloser is set on hold. It can be
connected to a thermal overload protection trip signal which resets only when the
thermal content has fallen to an acceptable level, for example, 70%. As long as the
signal is high, indicating that the line is hot, the auto reclosing is halted. When the
signal resets, a reclosing cycle will continue. This may cause a considerable delay
between start of the auto recloser and the breaker closing command. An external
logic limiting this time and activating the INHIBIT input can be used. The
THOLHOLD input can also be used to set the auto recloser on hold, for longer or
shorter time periods, for other purposes if for some reason the auto recloser needs
to be halted. The logic for thermal protection hold is shown in Figure
158.
Section 12 1MRK 505 394-UEN A
Control
340 Line differential protection RED650 2.2 IEC
Technical manual
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