Hi Learners, in this article we have listed 60+ important MCQs on Transmission and Distribution which will be useful for your competitive exams, various interviews, viva, and other exams. The questions and answers are all collected from different exams and interviews of previous years.
These listed MCQs will be helpful for your conceptual clarity and preparation about Transmission and Distribution.
1. A 3-phase 4-wire system is commonly used on
a) Primary transmission
b) Secondary transmission
c) Primary distribution
d) Secondary distribution
Answer: d
2. The loads on the distributor’s systems are generally
a) Balanced
b) Unbalanced
c) None of the above
Answer: b
3. Which of the following are the constants of the transmission lines?
a) Resistance
b) Inductance
c) Capacitance
d) All of the above
Answer: d
4. Due to which of the following reasons the cables should not be operated too hot?
a) The oil may loose its viscosity and it may start drawing off from higher levels
b) Expansion of the oil may cause the sheath to burst
c) Unequal expansion may create voids in the insulation which will lead to ionization
d) All of the above
Answer: d
5. When a live conductor of public electric supply breaks down and touches the earth which of the following will happen?
a) Current will flow to earth
b) Supply voltage will drop
c) Supply voltage will increase
d) No current will flow in the conductor
Answer: a
6. The angular displacement between two interconnected stations is mainly due to
a) Armature reactance of both alternators
b) Reactance of the interconnector
c) Synchronous reactance of both the alternators
d) All of the above
Answer: a
7. Constant voltage transmission entails the following disadvantage
a) Large conductor area is required for same power transmission
b) Short-circuit current of the system is increased
c) Either of the above
d) None of the above
Answer: b
8. The use of strain-type insulators is made where the conductors are
a) Dead ended
b) At intermediate anchor towers
c) Any of the above
d) None of the above
Answer: c
9. A circuit is disconnected by isolators when
a) Line is energized
b) There is no current in the line constant
c) Line is on full load
d) Circuit breaker is not open
Answer: b
10. A conductor, due to sag between two supports, takes the form
a) Semicircle
b) Triangle
c) Ellipse
d) Catenary
Answer: d
11. Most of the high-voltage transmission lines in India are
a) Underground
b) Overhead
c) Either of the above
d) None of the above
Answer: b
12. Which of the following methods is used for laying underground cables?
a) Direct laying
b) Draw-in-system
c) Solid system
d) All of the above
Answer: d
13. A uniformly loaded D.C. distributor is fed at both ends with equal voltages. As compared to a similar distributor fed at one end only, the drop at the middle point is
a) One-fourth
b) One-third
c) One-half
d) Twice
Answer: a
Also learn : Synchronous Motor: Working Principle, Types & Applications
14. Which of the following is not a constituent for making porcelain insulators?
a) Quartz
b) Kaolin
c) Felspar
d) Silica
Answer: d
15. In aluminum conductors, a steel core is provided to
a) Compensate for skin effect
b) Neutralise proximity effect
c) Reduce line inductance
d) Increase the tensile strength
Answer: d
16. For transmission of power over a distance of 200 km, the transmission voltage should be
a) 132 kV
b) 66 kV
c) 33 kV
d) 11 kV
Answer: a
17. When the interconnector between two stations has large reactance
a) The transfer of power will take place with voltage fluctuation and noise
b) The transfer of power will take place with least loss
c) The stations will fall out of step because of large angular displacement between the stations
d) None of the above
Answer: c
18. The skin effect of a conductor will reduce as the
a) Resistivity of conductor material increases
b) Permeability of conductor material increases
c) Diameter increases
d) Frequency increases
Answer: a
19. By which of the following systems electric power may be transmitted?
a) Overhead system
b) Underground system
c) Both (A) and (B)
d) None of the above
Answer: c
20. The square root of the ratio of line impedance and shunt admittance is called the
a) Surge impedance of the line
b) Conductance of the line
c) Regulation of the line
d) None of the above
Answer: a
21. The material commonly used for insulation in high-voltage cables is
a) Lead
b) Paper
c) Rubber
d) None of the above
Answer: b
22. Transmitted power remains the same, if the supply voltage of a D.C. 2-wire feeder is increased 100 percent, saving in copper is
a) 25 percent
b) 50 percent
c) 75 percent
d) 100 percent
Answer: b
23. Which of the following materials is used for overhead transmission lines?
a) Steel core aluminum
b) Galvanised steel
c) Cadmium copper
d) Any of the above
Answer: d
24. In AC.S.R. Conductors, the insulation between aluminum and steel conductors is
a) Insulin
b) Bitumen
c) Varnish
d) No insulation is required
Answer: d
25. The voltage drop, for constant voltage transmission, is compensated by installing
a) Inductors
b) Capacitors
c) Synchronous motors
d) All of above
Answer: c
26. In the analysis of which of the following lines shunt capacitance is neglected?
a) Short transmission lines
b) Medium transmission lines
c) Long transmission lines
d) Medium as well as long transmission lines
Answer: a
27. The following system is not generally used
a) 1-phase 3-wire
b) 1-phase 4-wire
c) 3-phase 3-wire
d) 3-phase 4-wire
Answer: a
28. ______ are the conductors, which connect the consumer’s terminals to the distribution.
a) Distributors
b) Service mains
c) Feeders
d) None of the above
Answer: b
29. Which of the following is the demerit of a ‘constant voltage transmission system’?
a)Increase of short-circuit current of the system
b) Availability of steady voltage at all loads at the line terminals
c) Possibility of better protection for the line due to possible use of higher terminal reactants
d) Improvement of power factor at times of moderate and heavy loads
Answer: a
30. Besides a method of trial and error, which of the following methods is employed for the solution of network problems in an interconnected system?
a)Circulating current method
b) Thevenin’s theorem
c) Superposition of currents
d) All of the above
Answer: d
31. Overhead lines generally use
a) Copper conductors
b) All aluminum conductors
c) C.S.R. conductors
d) None of the above
Answer: c
32. As compared to a 2-wire D.C. distributor, a 3-wire distributor with same maximum voltage to earth uses only
a) 25 percent of copper
b) 33.3 percent of copper
c) 66.7 percent of copper
d) 125 percent of copper
Answer: a
33. The steel used in steel core conductors is usually
a) Alloy steel
b) Stainless steel
c) Mild steel
d) High-speed steel
Answer: c
34. By Which of the following is a bus-bar is rated?
a) Current only
b) Current and voltage
c) Current, voltage, and frequency
d) Current, voltage, frequency, and short-time current
Answer: d
35. Which of the following equipment, for regulating the voltage in distribution feeder, will be most economical?
a) Static condenser
b) Synchronous condenser
c) Tap changing transformer
d) Booster transformer
Answer: d
36. Series capacitors on transmission lines are of little use when the load VAR requirement is
a) Large
b) Small
c) Fluctuating
d) Any of the above
Answer: b
37. The underground system cannot be operated above
a) 440 V
b) 11 KV
c) 33 KV
d) 66 KV
Answer: d
38. 310 km line is considered as
a) A long line
b) A medium line
c) A short line
d) Any of the above
Answer: a
39. The distributors for residential areas are
a) Single phase
b) Three-phase three wire
c) Three-phase four wire
d) None of the above
Answer: c
40. Which of the following is usually not the generating voltage?
a) 6 kV
b) 8.8 kV
c) 11 kV
d) 13.2 kV
Answer: b
41. The power transmitted will be maximum when
a) Corona losses are minimum
b) Reactance is high
c) Sending end voltage is more
d) Receiving end voltage is more
Answer: c
42. The material commonly used for sheaths of underground cables is
a) Lead
b) Rubber
c) Copper
d) Iron
Answer: a
43. High-voltage transmission lines use
a) Suspension insulators
b) Pin insulators
c) Both (A) and (B)
d) None of the above
Answer: a
44. The phenomenon of rising in voltage at the receiving end of the open-circuited or lightly loaded line is called the
a) See-back effect
b) Ferranti effect
c) Raman effect
d) None of the above
Answer: b
45. The Overhead system can be designed for operation up to
a) 11 kV
b) 33 kV
c) 66 kV
d) 400 kV
Answer: c
46. When a conductor carries more current on the surface as compared to core, it is due to
a) Permeability variation
b) Corona
c) Skin effect
d) Unsymmetrical fault
Answer: c
47. The effect of corona can be detected by
a) Presence of ozone detected by odour
b) the Hissing sound
c) Faint luminous glow of bluish color
d) All of the above
Answer: d
48. Pin-type insulators are generally not used for voltages beyond
a) 1 kV
b) 11 kV
c) 22 kV
d) 33 kV
Answer: d
49. Owing to skin effect
a)Current flows through the half cross-section of the conductor
b) Portion of the conductor near the surface carries more current and core of the conductor carries less current
c) Portion of the conductor near the surface carries less current and core of the conductor carries more current
d) Any of the above
Answer: b
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50. There is a greater possibility of the occurrence of the corona during
a) Dry weather
b) Winter
c) Summer heat
d) Humid weather
Answer: d
51. For which of the following equipment current rating is not necessary?
a) Circuit breakers
b) Isolators
c) Load break switch
d) Circuit breakers and load break switches
Answer: b
52. On which of the following factors skin effect depends?
a) Frequency of the current
b) Size of the conductor
c) Resistivity of the conductor material
d) All of the above
Answer: d
53. The wooden poles well impregnated with creosote oil or any preservative compound has life
a) From 2 to 5 years
b) 10 to 15 years
c) 25 to 30 year
d) 60 to 70 years
Answer: c
54. Which of the following D.C. distribution system is the simplest and lowest in first cost?
a) Radial system
b) Ring system
c) Interconnected system
d) None of the above
Answer: a
55. The power factor of industrial loads is generally
a) Unity
b) Lagging
c) Leading
d) Zero
Answer: b
56. The spacing between phase conductors of a 220 kV line is approximately equal to
a) 2 m
b) 5 m
c) 6 m
d) 8.5 m
Answer: c
57. Which of the following distribution systems is more reliable?
a) Radial system
b) Tree system
c) Ring the main system
d) All are equally reliable
Answer: c
58. In a substation, the following equipment is not installed
a) Exciters
b) Series capacitors
c) Shunt reactors
d) Voltage transformers
Answer: a
59. In a tap-changing transformer, the tapings are provided on
a) Primary winding
b) Secondary winding
c) High voltage winding
d) Any of the above
Answer: b
60. The voltage regulation in magnetic amplifier-type voltage regulator is affected by
a) Electromagnetic induction
b) Varying the resistance
c) Varying the reactance
d) Variable transformer
Answer: c
61. When an alternator connected to the bus bar is shut down the bus-bar voltage will
a) Fall
b) Rise
c) Remain unchanged
d) None of the above
Answer: c
62. The current drawn by the line due to corona losses is
a) Non-sinusoidal
b) Sinusoidal
c) Triangular
d) Square
Answer: a
63. A feeder, in a transmission system, feeds power to
a) Distributors
b) Generating stations
c) Service mains
d) All of the above
Answer: a
64. The minimum clearance between the ground and a 220 kV line is about
a) 3 m
b) 5.5 m
c) 7.0 m
d) 10.5 m
Answer: c
65. The voltage of the single-phase supply to residential consumers is
a) 110 V
b) 210 V
c) 230 V
d) 400 V
Answer: c
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