MGVCL Exam Paper (30-07-2021 Shift 2)
A generating station having 'n' section busbars each rated at Q kVA with ×% reactance is connected on the tie-bars systems through busbar reactances of b%. Determine the short circuit kVA if a 3-phase fault takes place on one section.

Q[(1/x) + (n-1)/(bn+x)]
Q[(1/x) - (n+1)/(bn-x)]
Q[(1/x) + (n+1)/(bn-x)]
Q[(1/x) + (n+1)/(bn+x)]

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MGVCL Exam Paper (30-07-2021 Shift 2)
The magnitude of the generator earth-fault current is limited by

inserting the stabilizing resistance in series with the relay
inserting suitable resistance in neutral grounding circuit
controlling field exciter
using higher rating CTs

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MGVCL Exam Paper (30-07-2021 Shift 2)
The miniature circuit breaker (MCB) with Class D trip characteristics trips instantaneously when the current flowing through it reaches ____ the rated current.

between 5 to 10 times
between 2 to 3 times
between 10 to 20 times
between 3 to 5 times

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