Switchgear Protections

21. Discrimination between main and back up protection is provided by the use of relays which are

  1. fact
  2. sensitive
  3. slow
  4. none of the above

Correct answer: (C)
slow

22. Distance relays are generally

  1. split-phase relays
  2. reactance relays
  3. impedance relays
  4. none of the above

Correct answer: (D)
none of the above

23. elays are used for phase faults on long line.

  1. Impedance
  2. Reactance
  3. Either of the above
  4. None of the above

Correct answer: (A)
Impedance

24. Fault diverters are basically

  1. fuses
  2. relays
  3. fast switches
  4. circuit breakers

Correct answer: (C)
fast switches

25. For cost and safety, the outdoor substations are installed for voltages above

  1. 11 kV
  2. 33 kV
  3. 60kV
  4. 110kV

Correct answer: (B)
33 kV

26. For the protection of power station buildings against direct strokes the requirements are

  1. interception
  2. interception and conduction
  3. interception, conduction and dissipation
  4. interception, conduction, dissipation and reflection

Correct answer: (C)
interception, conduction and dissipation

27. For which of the following protection from negative sequence currents is provided?

  1. Generators
  2. Motors
  3. Transmission line
  4. Transformers

Correct answer: (A)
Generators

28. For which of the following ratings of the transformer differential protection is recommended?

  1. above 30 kVA.
  2. equal to and above 5 MVA
  3. equal to and above 25 MVA
  4. none of the above

Correct answer: (B)
equal to and above 5 MVA

29. H.R.C. fuse, as compared to a rewirable fuse, has

  1. no ageing effect
  2. high speed of operation
  3. high rupturing capacity
  4. all of the above

Correct answer: (D)
all of the above

30. H.R.C. fuses provide best protection against

  1. overload
  2. reverse current
  3. open-circuits
  4. short-circuits

Correct answer: (D)
short-circuits

Previous
Page 3 of 10
Next
Copyright © EngineeringMCQ.com