Protective Relay MCQ

31. For the grounding of an entire substation

1. Counterpoises are used
2. Grounding rods are used
3. Grounding mats are used
4. Peterson coil is used

32. Power system protection is provided so that

1. Information is relayed
2. Faults are prevented
3. Damage subsequent to faults is mitigated
4. Economic operation of power system is achieved

33. Reactance relays are generally deployed for the phase faults in

1. Short lines
2. Medium lines
3. Long lines

The correct amongst the given is

1. only 1 and 2
2. only 2 and 3
3. none
4. only 1

34. In terms of relays, IDMT relays stands for

1. Inverse direct maximum time lag
2. Inverse definite maximum time lag
3. Inverse definite maximum time lag
4. None of these

35. The most efficient torque producing actuating structure for an induction-type relay is

1. Shaded pole structure
2. Watt-hour meter structure
3. Induction-cup structure
4. Single-induction loop structure

36. The induction cup structure is used in the

1. Differential relays
2. I.D.M.T. relays
3. Time delay relays
4. Mho relays

37. A pitot relay is used for

1. High-speed tripping
2. Delayed tripping
3. Preset tripping
4. No tripping

38. Impedance relay is used on ……… on transmission lines.

1. Short
2. Medium
3. Long
4.  All

39. If the fault current is 2000A, the relay setting is 50% and CT ratio is 400 : 5, then plug setting multiplier will be

1. 25 A
2. 15 A
3. 50 A
4. 10 A

40. For complete protection of a 3 phase line

1. Three-phase and three earth fault relays are required.
2. Three-phase and two earth fault relays are required.
3. Two-phase and two earth fault relays are required.
4. Two-phase and one earth fault relays are required.