Isolator in sub station is open under ------------- condition?

(A)  no load

(B) short circuit

(C)  full load

(D) any of the above


Answer: (A)  no load


Explanation:


Isolator does not contain any arc quenching medium, it must be open under no load condition only. 

On the both side of the every equipment isolators are provided. 

For attending maintenance working on equipments these isolators are opened


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