Cold Load Protection - Toshiba GRD110 Manual

GRD110
functions can also be initiated by external protections
via a binary input if required.
Inrush Current Detector
GRD110-500 and -520 provides an inrush current
detector against magnetizing inrush currents during
transformer energisation. The inrush current detector
detects the ratio between second harmonic current
and fundamental current.

Cold Load Protection

The cold load function modifies the overcurrent protection
settings for a period after energising the system. This
feature is used to prevent unwanted protection operation
when closing on to the type of load which takes a
high level of current for a period after energisation.
This is achieved by a 'Cold Load Settings Group' in
which the user can programme alternative settings.
Normally the user will choose higher current settings
and/or longer time delays and/or disable elements
altogether within this group.
Auto-Reclose
GRD110-500 and -520 provides an auto-reclose
function. Four independent sequences are provided,
one for each of the following:
Phase fault
Earth fault
Sensitive earth fault
External trip (initiated by a binary input)
Each sequence is independently programmable for
single shot, two shot, three shot, four shot or five shot
(i.e. six trips to lock-out) auto-reclose. Each
protection trip is programmable for instantaneous or
delayed operation, and each ARC shot has a
programmable dead time. Sequence co-ordination is
maintained between the auto-reclose sequences of
in-series relays on a feeder.
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