Answer Posted / mahmud

Impedance earthing - The purpose of this method is to limit
the current for greater safety.
There are 3 type-
1.Earthing through reactance.
2.Earthing through ARC - Suppression coil.
3.Earthing through resistor.

These parameters are needed to specify the earthing
resistor:
U : Rated voltage line to line voltage or system voltage
(kV)
If : Rated fault current (A)
T s : Rated time (Sec) - Duration of the fault
Resistance value :

R=U/(I.Sqare root3)

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