# Objective Type Question or MCQ of B. Economics of Operation page-3

21.Self GMD method is used to evaluate

a) Inductance
b) Capacitance.
c) Inductance and capacitance both
d) None of the above

Ans: (a)

22. Most economic load an underground cable will be

d) None of the above is necessary.

Ans: (b)

23. Corona loss on a particular system at 50 Hz is 1 kW/phase per km. The corona loss on the same system with supply frequency 25 Hz will be

a) 1 kW/phase/km.
b) 0.5 kW/phase/km.
c) 0.667 kW/phase/km.
d) None of the above.

Ans: (c)

24. Effect of bonding the cable is

a) To increase the effective resistance and inductance.
b) To increase the effective resistance but reduce inductance.
c) To decreases the effective resistance and inductance.
d) To decrease the effective resistance but increases the inductance.

Ans: (b)

25. For effective application of counterpoise it should be buried into the ground to a depth of

a) 1 meter.
b) 2 meters.
c) Just enough to avoid theft.
d) None of the above.

Ans: (c)

26. Corona loss is less when the shape of the conductor is

a) Circular.
b) Flat.
c) Oval.
d) Independent of shape.

Ans: (a)

27. A system is said to be effectively grounded if its

a) Neutral is grounded directly.
b) Ratio of X0/X1 > 3.0.
c) Ratio of X0/X1 > 2.0.
d) Ratio of X0/X1 < 3.0.

Ans: (d)

28. Velocity of travelling wave through a cable of relative per mittivity 9 is

a) 9 × 108 metres/sec.
b) 3 × 108 metres/sec.
c) 108 metres/sec.
d) 2 × 108 metres/sec.

Ans: (c)

29. Voltage at the two ends of a line are 132 kV and its reactance is 40 ohms. The capacity of the line is

a) 435.6 MW.
b) 217.8 MW.
c) 251.5 MW.
d) 500 MW.

Ans: (a)

30. For a lumped inductive load, with increase in supply frequency

a) P and Q increases.
b) P increases, Q decreases.
c) P decreases, Q increases.
d) P and Q decreases.

Ans: (c)