Q.38 The single line diagram of a balanced
power system is shown in the figure. The voltage magnitude at the generator
internal bus is constant and 1.0 p.u. The p.u. reactances of different
components in the system are also shown in the figure. The infinite bus voltage
magnitude is 1.0 p.u. A three phase fault occurs at the middle of line 2. The
ratio of the maximum real power that can be transferred during the pre-fault
condition to the maximum real power that can be transferred under the faulted
condition is _________.

Answer: 6

Q.39 The open loop transfer function of a
unity feedback control system is given by

Answer: (C)

Q.40 At no load condition, a 3-phase, 50 Hz,
lossless power transmission line has sending-end and receiving-end voltages of
400 kV and 420 kV respectively. Assuming the velocity of travelling wave to be
the velocity of light, the length of the line, in km, is ____________.

Answer: 301

Q.41 The power consumption of an industry is
500 kVA, at 0.8 p.f. lagging. A synchronous motor is added to raise the power
factor of the industry to unity. If the power intake of the motor is 100 kW,
the p.f. of the motor is _____________

Answer: 0.316

Q.42 The flux linkage (λ) and current (i)
relation for an electromagnetic system is ߣ = (√݅)/݃. When i = 2A and ݃ (air-gap length) = 10 cm, the magnitude of mechanical force on the
moving part, in N, is ________.

Answer: 14.14

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