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2.13 Autoreclose
The GRE110 series provides a multi-shot (five shots) autoreclosing scheme for single circuit
breaker application:
• A three phase autoreclosing scheme is used for all shots
• Autoreclosing counter
Autoreclosing (ARC) can be initialized by OC1 to OC4, EF1 to EF4, SEF1 to SEF4 trip signals or
external trip signals via binary inputs, as determined by scheme switches [∗∗∗∗-INIT]. Trip signals
are selected for ARC used/not used, by setting [∗∗∗∗-INIT] to "On" or "NA" respectively. If a trip
signal is used to block ARC, then [∗∗∗∗-INIT] is set to "BLK". ARC can also be blocked by using
programmable binary inputs ARCBLK.
Three-phase autoreclosing is provided for all shots, regardless of whether the fault is single-phase
or multi-phase. Autoreclosing can be programmed to provide any number of shots, from one to five.
In each case, if the first shot fails, then all subsequent shots apply three-phase tripping and
reclosing.
To disable the autoreclosing, scheme switch [ARCEN] is set to "Off".
The GRE110 also provides a manual close function. A manual close can be performed via
programmable binary inputs ARCMCL.
2.13.1 Scheme Logic
Figure 2.13.1 shows the simplified scheme logic for the autoreclose. Autoreclose becomes ready
when the circuit breaker is closed and ready for autoreclose (CB READY=1), the on-delay timer
TRDY is picked up, and the [ARCEN] is set to "ON". TRDY is used to determine the reclaim time.
If the autoreclose is ready, then reclosing can be activated by the PLC signal ARC_INIT, etc.
Auto-reclose conditions such as voltage and synchronism check VCHK, etc., can be provided by
PLC signals ARC-S∗_COND.
Once autoreclose is activated, it is maintained using a flip-flop circuit until one reclosing cycle is
completed.
Autoreclose success (ARC SUCCESS) or fail (ARC FAIL) can be displayed as an event record
message.
Multi-shot autoreclose
Regardless of the tripping mode, three-phase reclosing is performed. If the [ARCEN] is set to "On",
the dead time counter TD1 for three-phase reclosing is started. After the dead time has elapsed, the
reclosing command ARC-SHOT is initiated.
Multi-shot autoreclose can be executed up to four times after the first-shot autoreclose fails. The
multi-shot mode, one to five shots, is set with the scheme switch [ARC∗-NUM].
During multi-shot reclosing, the dead time counter TD2 for the second shot is activated if the first
shot autoreclose has been performed, but tripping occurs again. The second shot autoreclose is
performed after the period of time set on TD2 has elapsed. At this time, the outputs of the step
counter are: SP1 = 1, SP2 = 0, SP3 = 0, SP4 = 0 and SP5 = 0.
Autoreclose is completed at this step if the two shots mode is selected for the multi-shot mode. In
this case, tripping following a "reclose-onto-a-fault" becomes the final trip (ARC FT = 1).
If the three shot mode is selected for the multi-shot mode, autoreclose is further retried after the
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