Circuit Breakers MCQs

41. A three-phase, 33 kV oil circuit breaker is rated for 1200 A, 2000 MVA, 3s. The symmetrical breaking current is

1. 1200 A
2. 3600 A
3. 35 kA
4. 104.8 kA

42. In a circuit breaker, the time duration from the instant of the fault of the extinction of arc is known as

1. Total clearing time
2. Operation time
3. Protection time
4. Recovery time

43. In an indoor substation for 220 kV, the circuit breakers will be of the type

1. Oil
2. Air break
3. SF₆
4. Vaccum

44. Resistance switching is normally employed in

1. All breakers
2. Bulk oil breakers
3. Minimum oil breakers
4. Air blast breakers

45. Which is the preferred type of C.B. to be installed in the EHV system?

1. Vacuum C.B.
2. Air blast C.B.
3. Bulk oil C.B.
4. None of these

46. Circuit breaker is used for which of the following

1. Voltage control
2. Power control
3. Frequency control
4. Over control protection

47. Which one of the following is not a routine test of a circuit breaker?

1. Short circuit test
2. Dielectric test
3. Thermal test
4. DC resistance voltage drop test

48. The most suitable circuit breaker for interrupting short line fault without resistance switching is

1. Minimum oil circuit breaker
2. SF₆ circuit breaker
3. Bulk oil circuit breaker
4. Air blast circuit breaker

49. The restriking voltage in circuit breaker is measured in

1. RMS value
2. Peak value
3. Instantaneous value
4. Average value

50. The Air Blast circuit breakers for 400 kV system are designed to operate

1. 0.1 s
2. 0.5 s
3. 50 ms
4. 100 μs