Close on Fault Trip
The Close on Fault Trip is a feature helps to ensure that a single shot trip occurs if the switchgear is closed onto a fault when the detection is in the alarm mode.
It applies whenever a downstream fault is cleared by an upstream device within the Maximum Fault Period of the switchgear being closed by an operator.
The required conditions for a Close on Fault Trip to occur are:
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The Close on Fault Trip feature enabled.
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Switchgear close by a local or remote operator.
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At least one bushing is live at the time of the close request.
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Switchgear has to have closed onto a fault (A fault alarm is raised after the close).
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Supply is lost within the Maximum Fault Period from the close.
Close on Fault Trip Configuration
Close
on Fault Trip can be made available in WSOS Feature Selection only
if Per Element Detection is already available.
Attempts to make Close on Fault Trip available when
Per Element Detection is not available will cause WSOS to display
the message below.
Similarly an attempt to disable the Pre Element Detection feature when the Close on Fault Trip feature is enabled will also be rejected.
Maximum Fault Period
The configuration parameter required for the Close on Fault Trip feature is the Maximum Fault Period.
When the Close on Fault Trip feature is enabled, a configuration page by that name is added to the settings for each detection group displayed by WSOS.
The Maximum Fault Period is 10 s by default and can be configured from 1 s to 180 s in 1 s steps.
Figure 190
AS Maximum Fault Period setting
The Maximum Fault Period can also be set via the operator interface.