35
The warning signal generated in case of continuous light on the light
sensor inputs can be routed to SO2 by setting switch SGF1/8 to 1.
Arc I>
Arc I
0
>
SGF3/6=1
SGF3/7=1
SGF4/6=0
I
L
0
25 ms
Arc protection
Arc Trip
L> light output
Light sensor 1
Light sensor 2
External Arc
AND
OR
I
A040316_2
Fig. 5.1.4.7.-1 Block diagram of the arc protection
5.1.4.8. Auto-reclose function
The vast majority of MV overhead line faults are transient and automatically cleared
by momentarily de-energizing the line. De-energizing of the fault location for a
selected time period is implemented through automatic reclosing, during which
most faults can be cleared.
At a permanent fault, auto-reclosing is followed by definite tripping. A permanent
fault must be located and cleared before the fault location can be re-energized.
The auto-reclose (AR) function of REF 610 can be used with any circuit breaker
suitable for auto-reclosing. The AR function provides three programmable auto-
reclose shots and can thus be set to perform one to three successive auto-reclosures
of desired type and duration, one high-speed and one delayed, for instance.
The AR function can be initiated by pickup and trip signals from certain overcurrent
and earth-fault protection stages. Consequently, tripping of the arc protection stage,
for instance, does not initiate the AR function. Initiation is also possible from an
external device via a digital input.
The AR function can be inhibited (AR inhibit) by trip signals from certain
protection stages or via a digital input. Inhibition is advantageous with tripping
faults as this type of fault cannot be cleared during an auto-reclose sequence.
Tripping faults are detected by the CBFP, for instance. Inhibition will also interrupt
any ongoing shot.
The initiation of one or several auto-reclose shots can be set to be blocked by trip
signals from certain protection stages. Blocking is also possible via a digital input.
Blocking can be used to limit the number of shots in an auto-reclose sequence,
which may be advantageous with certain types of faults. In case of shot initiation
while a blocking is active, the next shot will be initiated.
Feeder Protection Relay
Technical Reference Manual
REF 610REF 610
1MRS755310
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