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Ground-fault protection switchable to I
2
t characteristic
The ground-fault protection modules for trip units ETU745 - 776 make it possible to switch over from a constant delay time to an
I
2
t characteristic.
This provides an inverse-time tripping characteristic with a constant I
2
t
g
value, providing better selectivity of the ground-fault protection in
systems with several grading levels.
The setting options for the delay time remain unchanged.
Switchover to the I
2
t
g
characteristic can be made via:
-the t
g
rotary coding switch (ETU745);
this must be set to a value in the white area.
- the graphical display (ETU776)
- TD400 and the software "powerconfig"
- the COM modules with a PC with the software “powerconfig” installed (page 29-2).
Ground-fault alarm
Ground-fault protection modules (page 9-44)
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