Close on Fault Trip
The Close on Fault Trip is a feature to help ensure that a single shot trip occurs if the switchgear is closed onto a fault when the protection 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:
-
The Close on Fault Trip feature enabled.
-
Switchgear close by a local or remote operator.
-
At least one bushing is live at the time of the close request.
-
Switchgear has to have closed onto a fault (A fault alarm is raised after the close).
-
Supply is lost within the Maximum Fault Period from the close.
Configuration
Close on Fault
Trip can be made available in WSOS Feature Selection only
if Per Element Protection is already available.
Attempts
to make Close on Fault Trip available when Per Element Protection
is not available will cause WSOS to display the message below.
Similarly an attempt to disable the Pre Element Protection 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 protection group displayed by WSOS. The Maximum Fault Period is 10 s by default and can be configured from 1 s...180 s in 1 s steps.
Figure 138
Close On Fault Trip setting
The Maximum Fault Period can also be set via the O.I. on flexVUE at:
> > Fault period,
and on setVUE on the Protection Setting 8 in the Protection menu.