If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded

If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then 

(A) zero sequence currents are present on both sides of the transformer 

(B) zero sequence currents are absent on both sides of the transformer 

(C) zero sequence currents are present on the secondary side but not on the primary side 

(D) zero sequence currents are present on the primary side but not on the secondary side
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1 Answer

Answer :

If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then zero sequence currents are absent on both sides of the transformer 

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