Quiz  /  Switchgear & Protection Gate & PSU MCQ Questions With Answers

  • 1. 
    Which among these are the main characteristics of a fuse element?

  • Low melting point
  • high conductivity
  • least detonation due to oxidation
  • all of the above

  • 2. 
    Lightning arrester is made up of which material?

  • Aluminium,
  • silicon oxide,
  • silver,
  • copper.

  • 3. 
    The hysteresis losses do not depend on

  • Volume of material
  • Magnetic field
  • Frequency
  • Either of them
  • None of these

  • 4. 
    38. Standard impulse testing of a power transformer requires:

  • (a) Two applications of chopped wave followed by one application of a full wave
  • (b) One application of chopped wave followed by one application of a full wave
  • (c) One application of chopped wave followed by two applications of a full wave
  • (d) None of the above.

  • 5. 
    A voltage source can be converted into constant current source by adding

  • Low resistance in parallel with the voltage source
  • High resistance in parallel with the voltage source
  • Low resistance in series with the voltage source
  • High resistance in series with the voltage source

  • 6. 
    Why sensationalized bus bar scheme is more reliable as compare to a single bus bar scheme due to to..

  • long time saving
  • due to extra breaker
  • due to section
  • all of these

  • 7. 
    The ground wire should not be smaller than No ______ copper.

  • 2
  • 4
  • 6
  • 10

  • 8. 
    Advantages of isolator is .......

  • safe from risk
  • helps to eliminate variations in output power
  • Moreover, it avoids frequency pulling due to changing loads.
  • all of these

  • 9. 
    The reflection co-efficient at the open circuited end of a transmission line.

  • 0
  • infinity
  • 1
  • none

  • 10. 
    A transmission line is protected by

  • inrush protection
  • distance protection
  • time graded and current graded over current protection
  • both (b) and (c)

  • 11. 
    Earthing of the transformer neutral through reactance will improve its

  • a) Transient stability
  • b) Steady state stability
  • c) dynamic stability,
  • d) all of the above.

  • 12. 
    SF6 is which type of gas?

  • electropositive
  • electro negative
  • invalid information
  • both A and B

  • 13. 
    Bus coupler is very essential in arrangement

  • single bus,
  • double bus, double breaker,
  • main and transfer bus,
  • all of the above.

  • 14. 
    16. Which of the following statements is incorrect ?

  • (a) Lightning arrestors are used before the switchgear
  • (b) Shunt reactors are used as compensation reactors
  • (c) The peak short current is (1.8 xV2) times the A.C. component
  • (d) The MVA at fault is equal to base MVA divided by per unit equivalent fault reactance.

  • 15. 
    Which one is apparatus protection

  • transmission protection
  • out of step protection
  • under frequency relay
  • islanding system

  • 16. 
    The interaction between a transmission line and communication line is minimized by

  • (a) transposing transmission as well as communication lines.
  • (b) increasing the height of the trans-mission line tower
  • (c) increasing the distance between the two lines
  • (d) all of the above

  • 17. 
    A Bucholz relay is used for

  • protection of a transformer against all internal faults
  • protection of a transformer against all external faults
  • protection of a transformer against both internal and external faults
  • protection of induction motors.

  • 18. 
    The current transformer can also be used to measured high d.c. current.

  • true
  • false

  • 19. 
    Input of relay is

  • temperature
  • power breakdown
  • warning alarm
  • communication

  • 20. 
    On which of the following routine tests are conducted?

  • Oil circuit breakers
  • Air blast circuit breakers
  • Minimum oil circuit breakers
  • All of the above

  • 21. 
    For cost and safety, the outdoor substations are installed for voltages above

  • 11 KV
  • 33KV
  • 60KV
  • 110KV

  • 22. 
    The maximum voltage for the switches is up to

  • up to 10kv
  • upto 15kv
  • up to25kv
  • up to35kv

  • 23. 
    When any material has negative magnetism, the material is called as

  • Paramagnetic
  • Diamagnetic
  • Ferromagnetic
  • Antiferromagnetic

  • 24. 
    27. Over fluxing protection is recommended for

  • (a) distribution transformer,
  • (b) generator transformer of the power plant
  • (c) auto-transformer of the power plant,
  • (d) station transformer of the power plant
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