Why 6.6 kV transformer is resistance grounded by 10 ohms and current limited to 400 A?

1 Answer

Answer :

a) To reduce burning and melting in faulted switchgear or machine.

b) To reduce mechanical stresses in equipment.

c) To reduce the electrical hazards by stray ground fault currents in the ground return path.

d) To reduce momentary line voltage dip due to ground fault.

e) The current is limited to 400a, that is ¼ th of the load current to reduce the size of the screen in 6.6 kV XLPE (cross-linked polyethylene). Therefore the cost of the cable decreases. 

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