The severity of line to ground and three phase faults at the terminals of an unloaded

The severity of line to ground and three phase faults at the terminals of an unloaded synchronous generator is to be same. If the terminal voltage is 1.0 pu, Z1=Z2=j0.1 p.u. and Z0= j0.05 p.u. for the alternator, then the required inductive reactance for neutral grounding is 

 (a) 0.05 p.u. (b) 0.0166 p.u. (c) 0.1 p.u. (d) 0.15 p.u.
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1 Answer

Answer :

The severity of line to ground and three phase faults at the terminals of an unloaded synchronous generator is to be same. If the terminal voltage is 1.0 pu, Z1=Z2=j0.1 p.u. and Z0= j0.05 p.u. for the alternator, then the required inductive reactance for neutral grounding is 0.0166 p.u.

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