Description
2.3 Protection system
3WA1 air circuit breaker
Equipment Manual, 02/2023, 92310000002-06
57
2.3.5.6 Ground-fault alarm
A ground fault can occur due to aging and the resulting deterioration of an insulating
component in a power distribution system or due to a foreign body in the system. If the
fault resistance is so high that the ground-fault current is below the settings of the
ground-fault protection, the electronic trip unit will not trip. With the ground-fault alarm,
a high-resistance ground fault can be detected without switching off the system. Then
the elimination of the fault must be initiated.
The ground-fault alarm detects fault currents between the conductors and grounded
parts of the power distribution system. It responds when the rms value of the ground-
fault current exceeds the set alarm threshold I
g alarm
for the duration of the set delay t
g
alarm
.
As an option, the ground-fault alarm function can detect intermittent faults over a period
of 5 s.
The intermittent detection is only available if a GF protective function is present and
intermittent detection for the GF protective function is activated. For more information,
see Chapter Ground-fault protection GF (Page 58).
Characteristic
To Next Page
Loading...
