About Power Systems

Following are some of the multiple choice questions on the Power Systems with answers that will help the students in developing their knowledge.

Power Systems MCQ

1. How much wind power does India hold?

  • 20,000 MW
  • 12,000 MW
  • 140,000 MW
  • 5000 MW

2. The overall efficiency of thermal power plant is equal to

  • Rankine cycle efficiency
  • Carnot cycle efficiency
  • Regenerative cycle efficiency
  • Boiler efficiency x turbine efficiency x generator efficiency

3. Solar thermal power generation can be achieved by

  • using focusing collector or heliostates
  • using flat plate collectors
  • using a solar pond
  • any of the above system

4. At what range of speed is the electricity from the wind turbine is generated?

  • 100 – 125 mph
  • 450 – 650 mph
  • 250 – 450 mph
  • 30-35 mph

5.  What should be the value of earthing resistance for large power stations?

  • 1 Ω
  • 0.5 Ω
  • 2 Ω
  • 5 Ω

6. The amount of energy available in the wind at any instant is proportional to ___ of the wind speed.

  • Square root power of two
  • Square root power of three
  • Square power
  • Cube power

7. When did the development of wind power in India began?

  • 1965
  • 1954
  • 1990
  • 1985

8.  If the load current decreases then the power factor

  • Will also decrease
  • Will increase
  • Will remains unchanged
  • None of these

9. Power factor of a load can be improved by using

  • Static capacitors
  • Synchronous condenser
  • Phase advancer
  • All of the above

10. Which of the following is not the distribution system normally used

  • 3 phase-4 wire
  • 3 phase-3 wire
  • Single phase - 3 wire
  • Single phase -4 wire.

11. Which type of system is generally adopted for the generation and transmission of electrical power?

  • 3 phase 4 wire
  • 2 phase 3 wire
  • 3 phase 3 wire
  • None of these

12. The steady state stability of the power system can be improved by

  • Increasing the number of parallel lines between the transmission points
  • Connecting capacitors in series with the line
  • Reducing the excitation of the machines
  • Both a and b

13. The stability of the power system is not affected by which among these?

  • Generator reactance
  • Line losses
  • Excitation of generators
  • All of these

14. Various power system faults in increasing order of severity are

  • LG,LL,LLG,LLLG
  • LLLG,LLG,LG,LL
  • LLG,LLLG,LL,LG
  • LL,LG,LLLG,LLG

15. What percentage of fault occurring in the power system is line to line fault

  • 5 %
  • 30 %
  • 25 %
  • 15 %

16. A _________ distribution system is more reliable than the ______ distribution system.

  • parallel, radial
  • parallel, ring
  • radial, parallel
  • ring, parallel

17. What is the expression for fault current in line to line fault?

  • If = √3 * (Ea / Z1 + Z2)
  • If = 3 * (Ea / Z1 + Z2)
  • If = √3 * (Ea / Z1 + Z2 + Z0)
  • If = 3 * (Ea / Z1 + Z2 + Z05)

18. Winds having following speed are suitable to operate wind turbines.

  • 5 – 25m/s
  • 10 – 35m/s
  • 20 – 45m/s
  • 30 – 55m/s

19. The rated voltage of a 3 phase power system is given by

  • rms peak voltage
  • Peak phase voltage.
  • rms line to line voltage
  • Peak line to line voltage.

20. What are the terminal conditions in case of SLG fault, if the fault occurs in the phase A?

  • Vb = 0, Ia = 0, Ic = 0
  • Va = 0, Ib = 0, Ic = 0
  • Va = 0, Ia = 0, Ic = 0
  • Vb = 0, Ia = 0, Ib = 0

21. The generating voltage and frequency in India is about?

  • 11 kV and 60 Hz
  • 11 kV and 50 Hz
  • 220 kV and 60 Hz
  • 220 kV and 50 Hz

22. The short circuit current of an alternator when short circuited on three phases will be

  • Zero as time goes to infinity
  • Maximum when time goes to infinity
  • Infinity when time goes to infinity
  • Small as time goes to infinity but not zero

23. The advantage of neutral earthing is

  • Freedom from persistent arcing grounds
  • Over voltages due to lightning can be discharged to earth
  • Simplified design earth fault protection
  • All of the above

24. When a line-to-line fault occurs, the short circuit current of an alternator depends upon its

  • Sub transient reactance
  • Transient reactance
  • Synchronous reactance
  • Short circuit reactance

25. Base impedance of the power system is given as:

  • (Base kV)2/Base MVA
  • (Base kV)/Base MVA
  • Base MVA/(Base kV)2
  • None of these

26. Which one of the following statements is NOT true?

  • When the equipment is designed at low power factor it is to be designed for more kVA
  • When power factor is decreased, loss in the cable supplying load is decreased.
  • Due to reduced power factor voltage regulation of line becomes poor 
  • Reduced power factor reduces the efficiency of the plant 

27. If power factor is less than unity then it will result in

  • Large kVA rating of equipment
  • Greater conductor size
  • Large copper losses
  • All of the above

28. Which of the following type of reactors are popularly used in power systems?

  • Compensation reactors
  • Current limiting reactors
  • Suppression or Peterson reactors
  • All of these

29. While designing the distribution to locality of one lac population with medium dense load requirement, we can employ ___________

  • radial system
  • parallel system
  • ring main system
  • any of the mentioned

30. In which part of the power system has lowest voltage?

  • Generation
  • Distribution
  • Transmission
  • Grid

31. What are the common assumptions made for the equal area criterion?

  • The transmission line and machine resistances are neglected
  • Rotor speed of the machine is constant
  • Mechanical input remains constant.
  • All of these

32. In India largest thermal power station is located at

  • Kota
  • Sarni
  • Chandrapur
  • Neyveli

33. . One would design the feeders of the transmission system based on its ____________

  • current capacity
  • voltage drop
  • operating voltage
  • all of the mentioned

34. What is the main source for the formation of wind?

  • Uneven land
  • Sun
  • Vegetation
  • Seasons

35. The amount of photo generated current increases slightly with increase in _________

  • Temperature
  • Photons
  • Diode current
  • Shunt current

36. The load flow solution is always assured in case of:

  • Newton-Raphson method
  • Gauss method
  • Gauss-Seidel method
  • None of these methods guarantees

37. In a star connected system without neutral grounding, zero sequence currents are

  • Zero
  • Phaser sum of phase currents
  • Same as r.m.s. value of phase currents
  • Same as peak value of phase currents

38. When alternating current passes through a conductor

  • it remains uniformly distributed throughout the section of conductor
  • portion of conductor near the surface carries more current as compared to the core
  • portion of conductor near the surface carries less current as compared to the core
  • entire current passes through the core of the conductor.

39. Skin effect is proportional to

  • diameter of conductor
  • (diameter of conductor)1/2
  • (diameter of conductor )2
  • none

40. A’ is an operator used to symmetrical component analysis

  • Which rotates the vector, it operates upon, through an angle 90° in the clockwise direction
  • Which rotates the vector, it operates upon, through an angle 120°, in the counter-clockwise direction
  • Which rotates the vector, it operates upon, through an angle 120°, in the clockwise direction
  • Which rotates the vector, it operates upon, through an angle 240°, in the clockwise direction

41. Wind energy is harnessed as ______ energy with the help of windmill or turbine.

  • Mechanical
  • Solar
  • Electrical
  • Heat

42. By using which component can the transient stability limit of a power system be improved?

  • Series resistance
  • Series capacitor
  • Series inductor
  • a. Shunt resistance

43. For the given distribution system the maximum voltage at the midpoint will be ________

  • 155.6 V
  • 311.12 V
  • 622 V
  • 220 V

44. In overhead transmission lines the effect of capacitance can be neglected when the length of line is less than

  • 200 km
  • 160 km
  • 100 km
  • 80 km.

45. Use of high speed circuit breaker will actually increase the system stability.

  • False
  • True

46. Which one of the following device is used for improving the power factor of the system:

  • Synchronous Phase Modifier
  • Shunt Reactor
  • Series Reactor
  • Asynchronous Generator

47. When a line to ground fault occurs,the current in faulted phase is 100 A.The zero sequence current in this case will be

  • 0 A
  • 33.3 A
  • 66.6 A
  • 100 A

48. For the single phase 2-wire system, the maximum voltage between the outer wires and earth is ______________

  • V/√2
  • √2V
  • V
  • 2V

49. Which among the following quantities are specified at the generator bus?

  • P and Q
  • P and |V|
  • Q and |V|
  • P and δ

50. Which one of the following loads has the poorest power factor?

  • Electric fan Induction motor 
  • Transformer 
  • Induction motor
  • Induction furnace

Enjoyed the Quiz. Share this with friends

Comments

Add Your Review

Your email address will not be published.

Subscribe to Newsletter!

Subscribe to get latest updates and information.