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Three-phase autoreclose (ARC)
The purpose of the autoreclose function (ARC) is to provide an efficient means of restoring
service following the tripping of circuit breakers (CBs) for temporary faults. The ARC function
is used to maintain the stability and synchronism of the system, whilst at the same time secure
the continuity of supply. The ARC function provides both a single-shot and multi-shot schemes;
the ARC function is designed for radial distribution lines, which can be protected together with
the overcurrent relays, Sectionalizers, and fuses; the ARC function is designed to reclose a
single CB.
In reclosing, whenever a fault occurs on the line, a CB is tripped to clear the fault and
recloses after a time delay. Generally, 80 to 90% of faults that do occur on lines are temporary
or transient faults, which can be cleared by the tripping and subsequent reclosing of the CB.
The remaining 10 to 20% of faults are either semi-permanent or permanent faults, such as
open conductor faults etc., which cannot be cleared by the opening and subsequent closing of
the CB.
Given the important purpose of autoreclose and the very significant problems mentioned
above, it is extremely important to distinguish between the temporary/transient fault and the
permanent fault and hence, we must select either the single-shot scheme or the multi-shot
scheme.
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6F2T0207 (0.01)
GRE200 (5,6)
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