MGVCL Exam Paper (30-07-2021 Shift 2)
A single phase motor connected to 415 V, 50 Hz supply takes 30 A at a power factor of 0.7 lagging. Calculate the capacitance required in parallel with the motor to raise the power factor to 0.9 lagging.

76.32 µF
66.32 µF
96.32 µF
86.32 µF

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MGVCL Exam Paper (30-07-2021 Shift 2)
A 50 Hz synchronous generator is connected to an infinite bus through a line. The p.u. reactances of generator and the line are j0.3 p.u. and j0.2 p.u. respectively. The generator no load voltage is 1.1 p.u. and that of infinite bus is 1.0 p.u. The inertia constant of the generator is 4 MW-sec/MVA. Determine the frequency of natural oscillations if the generator is loaded to 60% of its maximum power transfer capacity and small perturbation in power is given.

1.62 Hz
1.32 Hz
1.52 Hz
1.42 Hz

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MGVCL Exam Paper (30-07-2021 Shift 2)
The necessary equation to be solved during the load flow analysis using Fast-Decoupled method is given below:
where B' and B'' are formed using the imaginary part of the bus admittance matrix, Ybus. If the system consists of 6 buses of which one of the bus is slack bus and 2 bues are voltage regulated buses, then then the matrix B' is of order ____and the matrix B'' is of order____, respectivity.
∆P/|Vi| = - B'∆δ
∆Q/|Vi| = - B''∆|V|

5 and 3
3 and 5
3 and 6
6 and 3

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MGVCL Exam Paper (30-07-2021 Shift 2)
A 3-phase motor load has a p.f. of 0.397 lagging. The two wattmeter method used to measure power show the input as 30 kW. Find the reading on each wattmeter.

W1 = 10 kW and W2 = 20 kW
W1 = 5 kW and W2 = 25 kW
W1 = -5 kW and W2 = 35 kW
W1 = -10 kW and W2 = 40 kW

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

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

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