the power system configuration and the users practices and preferences. When the
circuit breaker only have three-phase operation, then three-phase auto reclosing has
to be chosen. This is usually the case in sub-transmission and distribution lines.
Three-phase tripping and reclosing for all types of faults is also widely accepted in
completely meshed power systems. In transmission systems with few parallel
circuits, single-phase reclosing for single-phase faults is an attractive alternative for
maintaining service and system stability.
AutoContinue: Automatic continuation to the next shot if the circuit breaker is not
closed within the set time of tAutoContWait. The normal setting is AutoContinue =
Off.
tAutoContWait: This is the length in time the auto recloser waits to see if the circuit
breaker is closed when AutoContinue is set to On. Normally, the setting of
tAutoContWait can be 2 sec.
StartByCBOpen: The normal setting Off is used when the function is started by
protection trip signals. If set On the start of the auto recloser is controlled by an
circuit breaker auxiliary contact.
LongStartInhib: Usually the protection trip command, used as an auto reclosing
start signal, resets quickly as the fault is cleared. A prolonged trip command may
depend on a circuit breaker failing to clear the fault. A protection trip signal present
when the circuit breaker is reclosed will result in a new trip. The user can set a
maximum start pulse duration time tLongStartInh. This start pulse duration time is
controlled by the LongStartInhib setting. When the 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.
tLongStartInh: The user can set a maximum start pulse duration time
tLongStartInh. At a set time somewhat longer than the auto reclosing dead time,
this facility will not influence the auto reclosing. A typical setting of tLongStartInh
could be close to the auto reclosing dead time.
tInhibit: To ensure reliable interruption and temporary blocking of the auto recloser
a resetting time delay tInhibit is used. The auto recloser will be blocked this time
after the deactivation of the INHIBIT input. A typical resetting delay is 5.0 s.
ZoneSeqCoord: The ZONESTEP input is used when coordination between local
auto reclosers and down stream auto reclosers is needed. When this input is
activated the auto recloser increases its actual shot number by one and enters
“reclaim time” status. If a start is received during this reclaim time the auto
recloser is proceeding as usual but with the dead time for the increased shot
number. Every new increase of the shot number needs a new activation of the
ZONESTEP input. The setting NoOfShots limits of course the possibility to
increase the shot number. This functionality is controlled by the setting
ZoneSeqCoord.
Section 12 1MRK 505 393-UEN B
Control
248 Line differential protection RED650 2.2 IEC
Application manual
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