GATE 2022 : Power System Quiz 11

A three phase, 33 kV oil circuit breaker is rated 1200 A,2000 MVA,3 secs. Then the making capacity is?

In a 132 kV system, the series inductance up to the point of circuit breaker location is 50 mH. The shunt capacitance at the circuit breaker terminal is 0.05 μF. The critical value of resistance in ohms required to be connected across the circuit breaker contacts which will give no transient oscillation is _____________.

The circuit breaker is used to protect 200 MVA, 220 kV 3-ϕ transformer. It trips when the magnetising current of transformer exceeds 50% of its operating value. The transformer is designed such that its magnetising current is 5% of full load current. If the inductance is 30 H and stray capacitance is 2000 μF, find the maximum voltage (in Volts) across circuit breaker to interrupt the magnetising current.

Consider a Merz price protection scheme, protecting a 3-phase ∆-Y transformer of 33/6.6 kV rating. If current transformer place on 6.6 kV side has (100: 1) ratio then current transformer ratio of 33 kV side will be (a: b). Ratio of a and b will be __________.