POWER SYSTEM DISTRIBUTION – MCQs

Q1. The usual primary distribution voltage in India is:
A) 400 V
B) 6.6 kV
C) 11 kV
D) 33 kV
Ans: C

Q2. The usual secondary distribution voltage in India is:
A) 110 V
B) 220/230 V
C) 400 V
D) 660 V
Ans: C

Q3. Distribution systems are generally designed for:
A) Constant current
B) Constant voltage
C) Variable frequency
D) None of the above
Ans: B

Q4. The distributor fed at one end only is called:
A) Radial distributor
B) Ring distributor
C) Double-fed distributor
D) Interconnected distributor
Ans: A

Q5. The distributor fed at both ends is called:
A) Radial distributor
B) Ring distributor
C) Double-fed distributor
D) Interconnected distributor
Ans: C

Q6. The distributor forming a closed loop is called:
A) Radial distributor
B) Ring main distributor
C) Interconnected distributor
D) None of these
Ans: B

Q7. Which system has the highest reliability?
A) Radial
B) Ring main
C) Interconnected
D) Both B and C
Ans: D

Q8. The common frequency of AC distribution in India is:
A) 25 Hz
B) 50 Hz
C) 60 Hz
D) 100 Hz
Ans: B

Q9. The load power factor in distribution systems is generally:
A) Unity
B) Lagging
C) Leading
D) Zero
Ans: B

Q10. For domestic consumers, supply is given by:
A) DC 3-wire
B) Single-phase 2-wire AC
C) Three-phase 3-wire AC
D) Three-phase 4-wire AC
Ans: D

Q11. Voltage drop in distribution is most affected by:
A) Line resistance
B) Line reactance
C) Power factor
D) All of the above
Ans: D

Q12. The size of a distributor is decided by:
A) Current carrying capacity
B) Voltage drop
C) Both A and B
D) None
Ans: C

Q13. The substation where distribution voltage is obtained from transmission voltage is:
A) Step-up substation
B) Step-down substation
C) Generating substation
D) None
Ans: B

Q14. The most common secondary distribution system is:
A) 1-phase, 2-wire
B) 1-phase, 3-wire
C) 3-phase, 3-wire
D) 3-phase, 4-wire
Ans: D

Q15. The most economical location of a distribution substation is:
A) Center of gravity of load
B) Far away from load
C) Near power plant
D) Near transmission line
Ans: A

Q16. In ring main system, if one section fails:
A) Whole system fails
B) Only that section is cut off
C) Supply is maintained from other side
D) None
Ans: C

Q17. Feeder size is determined by:
A) Current carrying capacity
B) Voltage drop
C) Power factor
D) Frequency
Ans: A

Q18. Distributor size is determined by:
A) Current carrying capacity
B) Voltage drop
C) Both A and B
D) Frequency
Ans: C

Q19. A feeder is:
A) Part of transmission system
B) Part of distribution system
C) Connector between source and distributor
D) Both B and C
Ans: D

Q20. The main disadvantage of radial system is:
A) Simplicity
B) Less reliability
C) Less maintenance
D) Economical
Ans: B

Q21. The interconnected system improves:
A) Reliability
B) Efficiency
C) Voltage regulation
D) All of the above
Ans: D

Q22. Load shedding is applied when:
A) Voltage increases
B) Power demand exceeds generation
C) Frequency is stable
D) None
Ans: B

Q23. Distribution lines generally use:
A) Underground cables
B) Overhead conductors
C) Both A and B
D) None
Ans: B

Q24. The voltage regulation of distribution system is better in:
A) Radial system
B) Ring main system
C) Interconnected system
D) Both B and C
Ans: D

Q25. Low voltage distribution for domestic purpose is usually:
A) 110 V
B) 220–240 V
C) 400 V
D) 660 V
Ans: B

Q26. High voltage distribution (for industries) is usually:
A) 400 V
B) 3.3 kV to 11 kV
C) 33 kV
D) 66 kV
Ans: B

Q27. The maximum permissible voltage drop in distribution systems is about:
A) 2%
B) 5%
C) 10%
D) 15%
Ans: B

Q28. Voltage drop is least in which distribution system?
A) Radial
B) Ring main
C) Interconnected
D) Both B and C
Ans: D

Q29. Power loss in distribution lines can be minimized by:
A) Using high voltage
B) Using low voltage
C) Increasing current
D) None
Ans: A

Q30. The efficiency of distribution system is maximum when losses are:
A) Equal to half of load
B) Equal to load
C) Minimum
D) Zero
Ans: C

Q31. The distributors for residential areas are:
A) Lightly loaded
B) Heavily loaded
C) Always DC
D) None
Ans: A

Q32. The distributors for industrial areas are:
A) Lightly loaded
B) Heavily loaded
C) Always AC
D) None
Ans: B

Q33. Which is cheaper for distribution?
A) DC
B) AC
C) Both same
D) Depends on load
Ans: B

Q34. Voltage fluctuations at consumer end cause:
A) Lamp flicker
B) Motor damage
C) Low efficiency
D) All of the above
Ans: D

Q35. The ring main system is preferred in:
A) Rural areas
B) Urban areas
C) Remote villages
D) None
Ans: B

Q36. Which one is NOT a distribution system?
A) Radial
B) Ring main
C) Interconnected
D) Star-delta
Ans: D

Q37. Distribution transformers usually have:
A) Delta-Delta connection
B) Star-Star connection
C) Delta-Star connection
D) Star-Delta connection
Ans: C

Q38. The frequency of supply in India is:
A) 25 Hz
B) 50 Hz
C) 60 Hz
D) 100 Hz
Ans: B

Q39. The efficiency of a good distribution system is about:
A) 60%
B) 70%
C) 80%
D) 90%
Ans: D

Q40. The most commonly used power factor improvement device in distribution is:
A) Capacitor
B) Inductor
C) Transformer
D) Synchronous motor
Ans: A

Q41. Underground distribution is more common in:
A) Cities
B) Villages
C) Hills
D) Remote areas
Ans: A

Q42. In India, the frequency tolerance allowed is:
A) ±5%
B) ±3%
C) ±1%
D) ±0.5%
Ans: A

Q43. Which is more reliable?
A) Overhead distribution
B) Underground distribution
C) Both same
D) None
Ans: B

Q44. The voltage of distribution system is stepped down from transmission voltage using:
A) Step-up transformer
B) Step-down transformer
C) Autotransformer
D) Phase transformer
Ans: B

Q45. The load curve of distribution shows:
A) Variation of current with time
B) Variation of voltage with time
C) Variation of load with time
D) None
Ans: C

Q46. Diversity factor of distribution system is always:
A) Less than 1
B) Equal to 1
C) Greater than 1
D) Zero
Ans: C

Q47. Maximum demand of a system is related to:
A) Average load
B) Connected load
C) Demand factor
D) All of the above
Ans: D

Q48. Power factor correction reduces:
A) Voltage
B) Current
C) Frequency
D) Resistance
Ans: B

Q49. The highest voltage used for distribution in India is:
A) 11 kV
B) 22 kV
C) 33 kV
D) 66 kV
Ans: C

Q50. A good distribution system should have:
A) Minimum losses
B) Good voltage regulation
C) Reliability
D) All of the above

Ans: D