TRANSMISSION AND DISTRIBUTION

 

1. Which of the following is usually not the generating voltage ?

A) 11 kV
B) 6.6 kV
C) 13.2 kV
D) 9.9 kV

ANSWER= (D)
Explain:- Generally 9.9 kV is not the generating voltage.

 

2. In AC.S.R. conductors, the insulation between aluminium and steel conductors is

A) Varnish
B) Insuline
C) Paper
D) No insulation required

ANSWER= (D)
Explain:- In AC.S.R. conductors, there is no requirement of the insulation between aluminium and steel conductors.

 

3. Overhead system can be designed for operation upto

A) 11 kV
B) 132 kV
C) 765 kV
D) 220 kV

ANSWER= (C)
Explain:- Overhead system can be designed for operation upto 765 kV.

 

4. The underground system cannot be operated above

A) 11 kV
B) 66 kV
C) 6.6 kV
D) 33 kV

ANSWER= (B)
Explain:- The underground system cannot be operated above 66 kV.

 

5. galvanized steel wire is generally used as

A) Structural components
B) Stay wire
C) Earth wire
D) All of the above

ANSWER= (D)
Explain:- galvanized steel wire is generally used for all of the above applications.

 

6. The operating voltage of high voltage cables is upto

A) 1.1 kV
B) 3.3 kV
C) 11 kV
D) 6.6 kV

ANSWER= (C)
Explain:- The operating voltage of high voltage cables is upto 11 kV.

 

7. The operating voltage of supertension cables is upto

A) 33 kV
B) 11 kV
C) 3.3 kV
D) 6.6 kV

ANSWER= (C)
Explain:- The operating voltage of supertension cables is upto 33 kV.

 

8. The operating voltage of extra high tension cables is upto

A) 33 kV
B) 11 kV
C) 132 kV
D) 6.6 kV

ANSWER= (C)
Explain:- The operating voltage of extra high tension cables is upto 132 kV.

 

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

A) 1 phase-4 wire
B) 1 phase-3 wire
C) 3 phase-4 wire
D) 3 phase-3 wire

ANSWER= (A)
Explain:- Single phase 4 wire is not the distribution system normally used.

 

10. Transmission efficiency increases as

A) Voltage and power factor both decrease
B) Voltage and power factor both increase
C) Voltage decreases but power factor increases
D) Voltage increases but power factor decreases

ANSWER= (B)
Explain:- Transmission efficiency increases as voltage and power factor both increase .

 

11. Conductors for high voltage transmission lines are suspended from towers

A) To reduce wind and snow loads
B) To reduce clearance from ground
C) To increase clearance from ground
D) None of the above

ANSWER= (C)
Explain:- Conductors for high voltage transmission lines are suspended from towers to increase clearance from ground.

 

12. The fact that a conductor carries more current on the surface as compared to core, is known as

A) Permeability
B) Corona
C) Skin effect
D) Proximity effect

ANSWER= (C)
Explain:- The fact that a conductor carries more current on the surface as compared to core, is known as skin effect.

 

13. The effective resistance of a conductor will be the same as ohmic resistance when

A) Current is minimum
B) Power factor is 0.5
C) Current is uniformly distributed in the conductor cross-section
D) Power loss is minimum

ANSWER= (C)
Explain:- The effective resistance of a conductor will be the same as ohmic resistance when current is uniformly distributed in the conductor cross-section.

 

14. Skin effect depends on

A) Frequency of the conductor
B) Size of the conductor
C) Resistivity of the material
D) All of the above

ANSWER= (D)
Explain:- Skin effect depends on all of the above factors.

 

15. Which is correct about skin effect

A) Skin effect is proportional to (Diameter of conductor)1/2
B) Skin effect is proportional to Diameter of conductor
C) Skin effect is proportional to (Diameter of conductor)2
D) Skin effect is independent on diameter

ANSWER= (C)
Explain:- Skin effect is proportional to (Diameter of conductor)2 .

 

16. In overhead transmission lines the effect of capacitance is neglected for analysis when the length of line is less than

A) 220 kM
B) 80 kM
C) 200 kM
D) None of the above

ANSWER= (B)
Explain:- In overhead transmission lines the effect of capacitance is neglected for analysis when the length of line is less than 80 kM.

 

17. Pin insulators are normally used

A) Up to 33 kV
B) Up to 132 kV
C) Up to 220 kV
D) Up to 11 kV

ANSWER= (A)
Explain:- Pin insulators are normally used up to 33 kV.

 

18. The number of insulator discs used for 66 kV line are

A) 3
B) 9
C) 12
D) 5

ANSWER= (D)
Explain:- For 66 kV lines the number of insulator discs used are 5.

 

19. Ten discs usually suggest that the transmission line voltage is

A) 132 kV
B) 220 kV
C) 66 kV
D) 11 kV

ANSWER= (A)
Explain:- Ten discs usually suggest that the transmission line voltage is 132 kV.

 

20. Corona usually occurs when the electrostatic stress in the air around the conductor succeeds

A) 11 kV (maximum value)/cm
B) 30 kV (maximum value)/cm
C) 22 kV (maximum value)/cm
D) 6.6 kV (maximum value)/cm

ANSWER= (B)
Explain:- Corona usually occurs when the electrostatic stress in the air around the conductor succeeds 30 kV (maximum value)/cm.

 

21. The current drawn by the line due to corona losses is

A) Rectangular
B) Sinusoidal
C) Triangular
D) Non - Sinusoidal

ANSWER= (D)
Explain:- The current drawn by the line due to corona losses is non-sinusoidal.

 

22. Between two supports, due to sag the conductor takes the form of

A) Rectangular
B) Catenary
C) Triangular
D) Semi-circle.

ANSWER= (B)
Explain:- Between two supports, due to sag the conductor takes the form of catenary.

 

23. The effect of ice deposition on conductor increases

A) Corona losses
B) Weight of conductor
C) Skin effect
D) None of the above

ANSWER= (B)
Explain:- The effect of ice deposition on conductor increases weight of conductor.

 

24. Which of the following statement is correct ?

A) Wind pressure reduces corona effects
B) Wind pressure and ice on conductors together improve regulation of power transmitted
C) Ice on conductors reduces power factor
D) Wind pressure is taken to act in a direction at right angles to that for ice

ANSWER= (D)
Explain:- Wind pressure is taken to act in a direction at right angles to that for ice .

 

25. Which of the following statement is correct ?

A) As the temperature rises the tension in the transmission line decreases
B) As temperature rises the sag in transmission lines reduces
C) As the temperature rises the tension in the transmission line increases
D) As temperature rises the span in transmission lines reduces

ANSWER= (A)
Explain:- As the temperature rises the tension in the transmission line decreases.

 

26. Maximum permissible span for wooden poles is

A) 100 meter
B) 30 meter
C) 60 meter
D) 12 meter

ANSWER= (C)
Explain:- Maximum permissible span for wooden poles is 60 meter.

 

27. For improving life, steel towers are galvanized with

A) Paint
B) Rubber
C) Zinc
D) Silver

ANSWER= (C)
Explain:- For improving life, steel towers are galvanized with zinc.

 

28. Full form of ACSR conductor is

A) Aluminum Conductor Silicon Reinforced
B) Anode Current Sinusoidally Run
C) Aluminum Conductor Steel Reinforced
D) None of the above

ANSWER= (C)
Explain:- ACSR stands for Aluminum Conductor Steel Reinforced.

 

29. The surge resistance of transmission lines is about

A) 400 Ω
B) 40 Ω
C) 400 kΩ
D) 100 Ω

ANSWER= (A)
Explain:- The surge resistance of transmission lines is about 400 Ω.

 

30. The surge resistance of underground cables is about

A) 400 Ω
B) 40 Ω
C) 40 kΩ
D) 200 Ω

ANSWER= (B)
Explain:- The surge resistance of underground cables is about 40 Ω.

 

31. The bundling of conductors is done primarily to

A) Increase reactance
B) Reduce reactance
C) Reduce radio interference
D) Increase radio interference

ANSWER= (B)
Explain:- The bundling of conductors is done primarily to reduce reactance.

 

32. Which of the following regulation is the best

A) 1 %
B) 10 %
C) 99 %
D) 50 %

ANSWER= (A)
Explain:- 1 % is the best regulation.

 

33. For a distortion-less transmission line

A) G/R = L*C
B) RC = LG
C) RLCG = 0
D) RL=CG

ANSWER= (B)
Explain:- For a distortion-less transmission line R/L = G/C.

 

34. Guard ring transmission line

A) Improves regulation
B) Improves power factor
C) Reduces earth capacitance of the lowest unit
D) increases transmission losses

ANSWER= (C)
Explain:- Guard ring transmission line reduces earth capacitance of the lowest unit.

 

35. A relay used for long transmission line is

A) Impedance relay
B) Mho relay
C) Reactance relay
D) None of the above

ANSWER= (B)
Explain:- A relay used for long transmission line is Mho relay.

 

36. A relay used for short transmission line is

A) Impedance relay
B) Mho relay
C) Reactance relay
D) None of the above

ANSWER= (C)
Explain:- A relay used for short transmission line is Reactance relay.

 

37. A relay used for medium transmission line is

A) Impedance relay
B) Mho relay
C) Reactance relay
D) None of the above

ANSWER= (A)
Explain:- A relay used for medium transmission line is Impedance relay.

 

38. Shunt capacitance is usually neglected in the analysis of

A) Long transmission lines
B) Medium transmission lines
C) Short transmission lines
D) All of the above

ANSWER= (C)
Explain:- Shunt capacitance is usually neglected in the analysis of short transmission lines.

 

39. The power transmitted will be maximum when

A) Receiving end voltage is more
B) Sending end voltage is more
C) Corona losses are least
D) Reactance is high

ANSWER= (B)
Explain:- The power transmitted will be maximum when sending end voltage is more.

 

40. The function of steel wire in a ACSR conductor is

A) To prevent corona
B) To provide mechanical strength
C) To take care of surges
D) To improve power factor

ANSWER= (B)
Explain:- The function of steel wire in a ACSR conductor is to provide mechanical strength.

 

41. Which type of insulators are used in 132 kV transmission lines ?

A) Pin type
B) Disc type
C) Shackle type
D) Post type

ANSWER= (B)
Explain:- Disc type insulators are used in 132 kV transmission lines.

 

42. String efficiency can be improved by

A) Grading the insulator
B) Using guard ring
C) Using longer cross arm
D) Any of the above

ANSWER= (D)
Explain:- String efficiency can be improved by using all of the above methods.

 

43. AC power is transmitted at high voltage

A) To minimize the transmission losses
B) To reduce the cost of generation
C) To make the system reliable
D) None of the above

ANSWER= (A)
Explain:- AC power is transmitted at high voltage to minimize the transmission losses.

 

44. In high voltage transmission lines the top most conductor is

A) Y-phase
B) R-phase
C) Earth wire
D) B-phase

ANSWER= (C)
Explain:- In high voltage transmission lines the top most conductor is earth wire.

 

45. The permissible voltage variation in transmission and distribution system is

A) ± 0.1 percent
B) ± 0.2 percent
C) ± 20 percent
D) ± 10 percent

ANSWER= (D)
Explain:- The permissible voltage variation in transmission and distribution system is ± 10 percent.

 

46. The voltage of transmission can be regulated by

A) Using tap changing transformers
B) Using series capacitors to neutralize the effect of series reactance
C) Using shunt capacitors at the receiving end during heavy loads
D) Any of the above

ANSWER= (D)
Explain:- The voltage of transmission can be regulated by using all of the above methods.

 

47. String efficiency is defined as

A) ((Voltage across the string) x (Numbers of discs on the string)) / (Voltage across disc nearest to the conductor)
B) (Voltage across the string) / ((Numbers of discs on the string) x (Voltage across disc nearest to the conductor))
C) (Voltage across disc nearest to the conductor))/ ((Numbers of discs on the string) x (Voltage across the string)
D) None of the above

ANSWER= (B)
Explain:- String efficiency = (Voltage across the string) / ((Numbers of discs on the string) x (Voltage across disc nearest to the conductor)).

 

48. Under no load conditions the current in a transmission line is due to

A) Line capacitance
B) Corona effects
C) Line resistance
D) None of the above

ANSWER= (A)
Explain:- Under no load conditions the current in a transmission line is due to line capacitance.

 

49. Which of the following distribution system is more reliable ?

A) Radial system
B) Tree system
C) Ring main system
D) All are equally reliable

ANSWER= (C)
Explain:- Ring main distribution system is more reliable.

 

50. What are the advantages of dc transmission system over ac transmission system ?

A) DC system is more economical
B) Corona limits are highest for dc circuits as compared to ac circuits
C) There is no skin effect
D) All of the above

ANSWER= (D)
Explain:- All of the above are the advantages of dc transmission system over ac transmission system.

 

51. The main advantage of ac. transmission system over d.c. transmission system is

A) Less insulation problems
B) Easy transformation
C) Less losses in transmission over long distances
D) Less problem of instability

ANSWER= (C)
Explain:- The main advantage of ac. transmission system over d.c. transmission system is less losses in transmission over long distances.

 

52. Step-up substations are associated with

A) Consumer locations
B) Distributors
C) Generating stations
D) Concentrated load

ANSWER= (C)
Explain:- Step-up substations are associated with generating stations.

 

53. Material generally used for bus bar is

A) Al
B) Cu
C) Zn
D) Steel

ANSWER= (A)
Explain:- Material generally used for bus bar is Aluminium.

 

54. Which of following properties has got higher value for aluminium as compared to copper?

A) Specific gravity
B) Melting point
C) Thermal conductivity
D) Electrical resistivity

ANSWER= (D)
Explain:- Aluminium has higher electrical resistivity as compared to copper.

 

55. Isolators are used to disconnect a circuit when

A) Line is energized
B) Circuit breaker is not open
C) Circuit breaker is open
D) Line is on full load

ANSWER= (C)
Explain:- Isolators are used to disconnect a circuit when circuit breaker is open.

 

56. Tap changing transformers are used for

A) Stepping down the voltage
B) Stepping up the voltage
C) Both stepping down the voltage and stepping up the voltage
D) None of the above

ANSWER= (C)
Explain:- Tap changing transformers are used for both stepping down and stepping up the voltage.

 

57. Which device automatically off the supply in the event of surges

A) Series capacitor
B) Isolator
C) Shunt reactor
D) Circuit breaker

ANSWER= (D)
Explain:- Circuit breaker automatically off the supply in the event of surges.

 

58. Which of the following correctly represents the sequence of operations of isolator circuit breaker and earthing switch while opening a circuit?

A) Close earthing switch - open circuit breaker open isolator
B) Open circuit breaker - open isolator - close earthing switch
C) Open isolator - close circuit breaker - open earthing switch
D) Close circuit breaker - close isolator - open earthing switch

ANSWER= (B)
Explain:- While opening a circuit correct sequence is → Open circuit breaker - open isolator - close earthing switch.

 

59. Which of the following correctly presents the sequence of operations of isolator circuit breaker and earthing switch while closing a circuit ?

A) Ensure circuit breaker is open - close isolator - open earthing switch if any close circuit breaker
B) Ensure circuit breaker is closed - close isolator - open earthing switch
C) Ensure circuit breaker is open - open isolator - open earthing switch if any - close circuit breaker
D) Close circuit breaker - close isolator - open earthing switch

ANSWER= (A)
Explain:- While closnig a circuit correct sequence is → Ensure circuit breaker is open - close isolator - open earthing switch if any close circuit breaker.

 

60. A 50 km transmission line carrying power at 33 kV is known as

A) Short transmission line
B) Medium transmission line
C) Long transmission line
D) EHV line

ANSWER= (A)
Explain:- A 50 km transmission line carrying power at 33 kV is known as short transmission line.

 

61. Which of the following D.C. distribution system is the simplest and lowest in first cost?

A) Inter-connected system
B) Radial system
C) Ring system
D) None of the above

ANSWER= (B)
Explain:- Radial D.C. distribution system is the simplest and lowest in first cost.

 

62. The distributors for residential areas are

A) Three-phase four wire
B) Single phase
C) Three-phase three wire
D) None of the above

ANSWER= (C)
Explain:- The distributors for residential areas are three-phase four wire.

 

63. The conductors of the overhead lines are

A) Stranded
B) Solid
C) Both solid and stranded
D) None of the above

ANSWER= (A)
Explain:- The conductors of the overhead lines are Stranded.

 

64. The loads on distributors systems are generally

A) Balanced
B) Unbalanced
C) Either balanced or unbalanced
D) None of the above

ANSWER= (B)
Explain:- The loads on distributors systems are generally unbalanced.

 

65. The minimum clearance between the ground and a 220 kV line is about

A) 4.4 m
B) 5.6 m
C) 7.0 m
D) 10.5 m

ANSWER= (C)
Explain:- The minimum clearance between the ground and a 220 kV line is about 7.0 m.

 

66. The spacing between phase conductors of a 220 kV line is approximately equal to

A) 1.4 m
B) 6.0 m
C) 3.0 m
D) 10.5 m

ANSWER= (B)
Explain:- The spacing between phase conductors of a 220 kV line is approximately equal to 6.0 m.

 

67. Large industrial consumers are supplied electrical energy at

A) 400 V
B) 6.6 kV
C) 67 kV
D) 220 kV

ANSWER= (C)
Explain:- Large industrial consumers are supplied electrical energy at 67 kV.

 

68. In a D.C. 3-wire distribution system, balancer fields are cross-connected in order to

A) Balance loads on both sides of the neutral
B) Boost the generated voltage
C) Equalize voltages on the positive and negative outers
D) Make both machines run as unloaded motors

ANSWER= (C)
Explain:- In a D.C. 3-wire distribution system, balancer fields are cross-connected in order to equalize voltages on the positive and negative outers.

 

69. In a D.C. 3-wire distributor using balancers and having unequal loads on the two sides

A) Both balancers run as motors
B) Both balancers run as generators
C) Balancer connected to heavily- loaded side runs as a motor
D) Balancer connected to lightly- loaded side runs as a motor

ANSWER= (D)
Explain:- In a D.C. 3-wire distributor using balancers and having unequal loads on the two sides. Balancer connected to lightly- loaded side runs as a motor.

 

70. Transmitted power remaining the same, if supply voltage of a D.C. 2-wire feeder is increased 100 percent, saving in copper is

A) 100 percent
B) 75 percent
C) 50 percent
D) 25 percent

ANSWER= (C)
Explain:- Transmitted power remaining the same, if supply voltage of a D.C. 2-wire feeder is increased 100 percent, saving in copper is 50 percent.

 

71. 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)
Explain:- 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 one-fourth.

 

72. As compared to a 2-wire D.C. distributor, a 3-wire distributor with same maximum voltage to earth uses only

A) 33.3 percent of copper
B) 31.25 percent of copper
C) 66.7 percent of copper
D) 75 percent of copper

ANSWER= (B)
Explain:- As compared to a 2-wire D.C. distributor, a 3-wire distributor with same maximum voltage to earth uses only 31.25 percent of copper.

 

73. A feeder, in a transmission system, feeds power to

A) Generating stations
B) Service mains
C) Distributors
D) All of the above

ANSWER= (C)
Explain:- A feeder, in a transmission system, feeds power to Distributors.

 

74. The power transmitted will be maximum when

A) Corona losses are minimum
B) Sending end voltage is more
C) Receiving end voltage is more
D) Reactance is high

ANSWER= (B)
Explain:- The power transmitted will be maximum when sending end voltage is more.

 

75. Which of the following bus-bar schemes has the lowest cost?

A) Single bus-bar scheme
B) Ring bus-bar scheme
C) Main and transfer scheme
D) Breaker and a half scheme

ANSWER= (A)
Explain:- Single bus-bar scheme has the lowest cost.

 

76. By which of the following 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)
Explain:- A bus-bar is rated by current, voltage, frequency and short time current.

 

77. 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)
Explain:- The 1-phase 3 wire system is not generally used.

 

78. When a live conductor of public electric supply breaks down and touches the earth which of the following will happen?

A) Supply voltage will drop
B) Supply voltage will increase
C) No current will flow in the conductor
D) Current will flow to earth

ANSWER= (D)
Explain:- When a live conductor of public electric supply breaks down and touches the earth then current will flow to earth.

 

79. If K is the volume of cable conductor material required to transmit power, then for the transmission of the same power, the volume of cable conductor required for single phase 2 wise AC system is

A) 2K
B) K cosφ
C) K/ cos^2φ
D) 2K/ cos^2 φ

ANSWER= (D)
Explain:- If K is the volume of cable conductor material required to transmit power, then for the transmission of the same power, the volume of cable conductor required for single phase 2 wise AC system is 2K/ cos^2 φ.

 

80. Neglecting losses in a transmission system, if the voltage is doubled, for the same power transmission, the weight of conductor material required will be

A) Four times
B) Double
C) One fourth
D) Half

ANSWER= (C)
Explain:- Neglecting losses in a transmission system, if the voltage is doubled, for the same power transmission, the weight of conductor material required will be one fourth.

 

81. The service mains connect

A) Distributor and transformer
B) Distributor and consumer terminals
C) Transformer and earth
D) Distributor and relay system

ANSWER= (B)
Explain:- The service mains connect distributor and consumer terminals.

 

82. Which of the following is a leading power system?

A) Reactors
B) Mercury arc rectifiers
C) Transformers
D) Underground cables

ANSWER= (D)
Explain:- Underground system is a leading power system.

 

83. The permissible voltage variable in voltage in distribution is

A) 0.2%
B) 1%
C) 10%
D) 50%

ANSWER= (C)
Explain:- The permissible voltage variable in voltage in distribution is 10%.

 

84. Which bus bar scheme offers the lowest cost?

A) Single bus bar scheme
B) Breaker and a half scheme
C) Main and transfer scheme
D) Ring bus bar scheme

ANSWER= (A)
Explain:- Single bus bar scheme offers the lowest cost.

 

85. Which is the most expensive bus bar scheme?

A) Single bus bar scheme
B) Double bus bar double breaker
C) Main and transfer scheme
D) Ring bus bar scheme

ANSWER= (B)
Explain:- Double bus bar double breaker is the most expensive bus bar scheme.

 

86. Out of the following systems of distribution, which system offers the best economy?

A) AC single phase system
B) AC 3 phase 3 wire system
C) AC 3 phase 4 wire system
D) Direct current system

ANSWER= (D)
Explain:- Out of the following systems of distribution, Direct current system offers the best economy.

 

87. Transmission lines link

A) Service points to consumer premises
B) Receiving end station to distribution transformer
C) Distribution transformer to consumer premises
D) Generating station to receiving end station

ANSWER= (D)
Explain:- Transmission lines link generating station to receiving end station.

 

8888. What is the minimum clearance of HV lines from ground across the streets?

A) 2 m
B) 4 m
C) 6 m
D) 10 m

ANSWER= (C)
Explain:- 6 meter is the minimum clearance of HV lines from ground across the streets.

 

89. Minimum horizontal clearance of a low voltage transmission line from residential buildings must be

A) 1.2 m
B) 4 m
C) 0.6 m
D) 0.2 m

ANSWER= (A)
Explain:- Minimum horizontal clearance of a low voltage transmission line from residential buildings must be 1.2 meter.

 

90. If a 132 kV line passes over a residential building, what shall be the minimum vertical clearance from the roof of the building?

A) 1.2 m
B) 4 m
C) 4.57 m
D) 6.38 m

ANSWER= (C)
Explain:- If a 132 kV line passes over a residential building, 4.57 meter shall be the minimum vertical clearance from the roof of the building.

 

91. What is the horizontal spacing between phase conductors of 132 kV line?

A) 8 m
B) 11 m
C) 14 m
D) 18 m

ANSWER= (A)
Explain:- 8 metre is the horizontal spacing between phase conductors of 132 kV line.

 

92. If a 66 kV lines passes over a residential building, the minimum vertical clearance from the roof of the building must be

A) 8 feet
B) 10 feet
C) 13 feet
D) 18 feet

ANSWER= (C)
Explain:- If a 66 kV lines passes over a residential building, the minimum vertical clearance from the roof of the building must be 13 feet.

 

93. By which of the following systems electric power may be transmitted?

A) Underground system
B) Overhead system
C) Both A and B
D) None of these

ANSWER= (C)
Explain:- Option C is correct.

 

94. If variable part of annual cost on account of interest and depreciation on the capital outlay is equal to the annual cost of electrical energy wasted in the conductors, the total annual cost will be minimum and the corresponding size of conductor will be most economical. This statement is known as

A) Kirchhoff’s law
B) Kelvin’s law
C) Faraday’s law
D) None of these

ANSWER= (B)
Explain:- If variable part of annual cost on account of interest and depreciation on the capital outlay is equal to the annual cost of electrical energy wasted in the conductors, the total annual cost will be minimum and the corresponding size of conductor will be most economical. This statement is known as Kelvin’s law.

 

95. The voltage of the single phase supply to residential consumers is

A) 110 V
B) 200 V
C) 230 V
D) 400 V

ANSWER= (C)
Explain:- The voltage of the single phase supply to residential consumers is 230 V.

 

96. Most of the high voltage transmission lines in India are

A) Overhead
B) Underground
C) Either of the above
D) None of these

ANSWER= (A)
Explain:- Most of the high voltage transmission lines in India are Overhead.

 

97. Which of the following is usually not the generating voltage?

A) 8.8 kV
B) 11 kV
C) 6.6 kV
D) 13.2 kV

ANSWER= (A)
Explain:- 8.8 kV is usually not the generating voltage.

 

98. A 3-phase 4 wire system is commonly used on

A) Primary transmission
B) Secondary transmission
C) Primary distribution
D) Secondary distribution

ANSWER= (D)
Explain:- A 3-phase 4 wire system is commonly used on secondary distribution.

 

9999. Which of the following distribution systems is more reliable?

A) Tree system
B) Radial system
C) Ring main system
D) All are equally reliable

ANSWER= (C)
Explain:- Ring main distribution system is more reliable.

 

100. Usually, electric power systems are represented via:

A) Single line diagram
B) Three-phase diagrams
C) Two-phase diagram
D) None of these

ANSWER= (A)
Explain:- Usually, electric power systems are represented via single line diagram.

 

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

A) 11 kV and 50 Hz
B) 11 kV and 60 Hz
C) 132 kV and 50 Hz
D) 132 kV and 60 Hz

ANSWER= (A)
Explain:- The generating voltage and frequency in India is about 11 kV and 50 Hz.

 

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

A) Peak phase voltage
B) Peak line to line voltage
C) RMS peak voltage
D) RMS line to line voltage

ANSWER= (D)
Explain:- The rated voltage of a 3 phase power system is given by RMS line to line voltage.

 

103. What is the main reason for using the high voltage for the long distance power transmission?

A) Increase in system reliability
B) Reduction in the transmission losses
C) Reduction in the time of transmission
D) None of these

ANSWER= (B)
Explain:- The main reason for using the high voltage for the long distance power transmission is reduction in the transmission line losses.

 

104. What is the highest possible transmission voltage in India

A) 132 kV
B) 400 kV
C) 765 kV
D) 220 kV

ANSWER= (C)
Explain:- The highest possible transmission voltage in India is 765 kV.

 

105. For the same conductor length, same amount of power, same losses and maximum voltage to earth, which system requires minimum conductor area?

A) 2 wire DC
B) 3 wire AC
C) 2 wire AC
D) Single phase system

ANSWER= (C)
Explain:- For the same conductor length, same amount of power, same losses and maximum voltage to earth, 3 wire ac system requires minimum conductor area.

 

106. The most important disadvantage of using the high voltage for transmission is

A) The increased cost of insulating the conductors
B) The increased cost of transformers, switchgear and the other terminal apparatus
C) Both A and B
D) None of these

ANSWER= (C)
Explain:- Option C is correct.

 

107. Line efficiency increases for ________ transmission voltages

A) Lower
B) Higher
C) Both A and B
D) None of these

ANSWER= (B)
Explain:- Line efficiency increases for higher transmission voltages.

 

108. Greater the power factor the ________________ is the volume of copper required

A) Smaller
B) Greater
C) Both A and B
D) None of these

ANSWER= (A)
Explain:- Greater the power factor the Smaller is the volume of copper required.

 

109. In transmission system, the weight of copper used is proportional to

A) Square of voltage
B) 1 / voltage
C) Voltage
D) 1 / (square of voltage)

ANSWER= (D)
Explain:- In transmission system, the weight of copper used is proportional to 1/(square of voltage).

 

110. With the same maximum voltage to earth, which among the following AC systems with 0.8 pf will need more copper compared to 2 wire system?

A) Single phase, 2 wire
B) Single phase, 3 wire
C) Three phase, 4 wire
D) Three phase, 3 wire

ANSWER= (C)
Explain:- With the same maximum voltage to earth, Three phase, 4 wire AC systems with 0.8 pf will need more copper compared to 2 wire system.

 

111. Which of these systems uses the 3 phase 4 wire system?

A) Primary transmission
B) Secondary transmission
C) Primary distribution
D) Secondary distribution

ANSWER= (D)
Explain:- Secondary distribution system uses the 3 phase 4 wire system.

 

112. What does the point P refer to?

A) Most economical power transmission
B) Most economical area of cross section
C) Both A and B
D) None of these

ANSWER= (B)
Explain:- Option B is correct.

 

113. In the following graph what does curve 2 represent?

A) Relation between annual cost of energy wasted and area of cross section
B) Relation between annual charge and the area of cross section
C) Both A and B
D) None of these

ANSWER= (A)
Explain:- Option A is correct.

 

114. In the following graph what does the straight line represent?

A) Relation between annual cost of energy wasted and area of cross section
B) Relation between annual charge and the area of cross section
C) Both A and B
D) None of these

ANSWER= (B)
Explain:- Option B is correct.

 

115. The account of interest and depreciation on the capital cost of complete installation of transmission line is denoted by which factor?

A) Annual cost of energy wasted
B) Annual charge on capital outlay
C) Both A and B
D) None of these

ANSWER= (B)
Explain:- The account of interest and depreciation on the capital cost of complete installation of transmission line is denoted by annual charge on capital outlay.

 

116. Which among these is/are the fundamental economical principles that influence/s the design of transmission lines?

A) Economic choice of transmission voltage
B) Economic choice of conductor size
C) Both A and B
D) None of these

ANSWER= (C)
Explain:- Option C is correct.

 

117. What is the total resistance in a single phase or 2 – wire dc line?

A) Half of the resistance of either conductor
B) Equal to the resistance of either conductor
C) Double the resistance of either conductor
D) None of these

ANSWER= (C)
Explain:- The total resistance in a single phase or 2 – wire dc line is double the resistance of either conductor.

 

118. Which type of loads use 3 phase 4 wire ac system of distribution?

A) Unbalanced
B) Balanced
C) Both A and B
D) None of these

ANSWER= (A)
Explain:- Unbalanced loads use 3 phase 4 wire ac system of distribution.

 

119. For purely domestic loads which type of distribution is employed?

A) 3 phase 3 wire
B) Single phase two wire
C) 3 phase 4 wire
D) None of these

ANSWER= (B)
Explain:- For purely domestic loads single phase two wire distribution system is employed.

 

120. Installation of capacitors at suitable locations and of optimum size in a distribution system results in 

i. Improved voltage regulation 

ii. Reduction in distribution power losses 

iii. Reduction of kVA rating of distribution transformers 

Which among the above statements are correct?

A) i only
B) i and ii only
C) iii only
D) All of these

ANSWER= (D)
Explain:- All are correct.

 

121. A uniformly loaded dc distributor is fed at both ends with equal voltages. In comparison to a similar distributor fed at one end only, what will be the drop at the midpoint be?

A) One fourth
B) One third
C) Half
D) One sixth

ANSWER= (B)
Explain:- Option B is correct.

 

122. A uniformly loaded dc distributor is fed at both ends with equal voltages. In comparison to a similar distributor fed at one end only, what will be the maximum voltage drop?

A) One fourth
B) One third
C) Half
D) One sixth

ANSWER= (A)
Explain:- Option A is correct.

 

123. A distribution system is shown in figure with load currents as marked. The two ends of the feeder are fed by voltage sources such that Vp = Vq = 3 V, the value of the voltage Vp for a minimum voltage of 220 V at any point along the feeder is

A) 222.89 V
B) 225.89 V
C) 220 V
D) 228.58 V

ANSWER= (B)
Explain:- Option B is correct.

 

124. What is the loss factor in a distribution system?

A) 0.5 * (load factor)
B) Load factor
C) 0.7 * load factor + 0.3 (load factor)^2
D) 0.3 * load factor + 0.7 (load factor)^2

ANSWER= (C)
Explain:- Loss factor = 0.7 * load factor + 0.3 (load factor)^2.

 

125. If the voltage of the system is about 230 V, then what would be the highest and the lowest permissible voltage?

A) 240 and 210 V
B) 244 and 216 V
C) 244 and 212 V
D) 242 and 214 V

ANSWER= (B)
Explain:- If the voltage of the system is about 230 V, then 244 and 216 V would be the highest and the lowest permissible voltage (± 6 % variation).

 

126. Which distribution system is energised by two or more generating stations or substations?

A) Ring main systems
B) Radial systems
C) Interconnected systems
D) All of these

ANSWER= (C)
Explain:- Interconnected distribution system is energised by two or more generating stations or substations.

 

127. The null point of a uniformly loaded distributor feed at equal voltage at both ends lies at

A) Either end
B) Mid point
C) One fourth distance from one end
D) Two third distance from one end

ANSWER= (B)
Explain:- The null point of a uniformly loaded distributor feed at equal voltage at both ends lies at mid point.

 

128.  What is the main advantage of ring main system over radial system? 

i. Voltage drop in the feeder is less. 

ii. Power factor is higher. 

iii. Supply is more reliable. 

Which among the above statements are correct?

A) ii and iii only
B) i and iii only
C) i, ii and iii
D) i and ii only

ANSWER= (B)
Explain:- Option B is correct.

 

129. Where the radial systems are generally employed?

A) Where power is generated at low voltage
B) Where power is generated at low voltage and substation is located at the centre of the load
C) Where power is generated at high voltage and substation is located at the centre of the load
D) Where power is generated at high voltage

ANSWER= (B)
Explain:- The radial systems are generally employed where power is generated at low voltage and substation is located at the centre of the load.

 

130. What is the permissible limit of voltage variations allowed in the distribution systems?

A) ± 5 %
B) ± 10 %
C) ± 6 %
D) ± 15 %

ANSWER= (C)
Explain:- The permissible limit of voltage variations allowed in the distribution system is ± 6 %.

 

131. The cost of material used in a distribution circuit per kVA of the distributed power varies as

A) Directly according to (supply area)^2
B) Square of linear dimensions of supply area
C) Cube of linear dimensions of supply area
D) None of these

ANSWER= (A)
Explain:- The cost of material used in a distribution circuit per kVA of the distributed power varies as directly according to (supply area)^2.

 

132. Which component connects the substation to the area where power is to be distributed?

A) Feeders
B) Service mains
C) Distributors
D) None of these

ANSWER= (A)
Explain:- Feeders connect the substation to the area where power is to be distributed.

 

133. What is the main type of distribution system in India?

A) Network
B) Parallel
C) Radial
D) All of these

ANSWER= (C)
Explain:- The main type of distribution system in India is Radial.

 

134. What is the horizontal spacing between phase conductors of 132 kV line?

A) 8 m
B) 11 m
C) 18 m
D) 3 m

ANSWER= (A)
Explain:- 8 meter is the horizontal spacing between phase conductors of 132 kV line.

 

135. What is the minimum clearance provided for the 132 kV line from the ground?

A) 10.5 m
B) 3.2 m
C) 7.5 m
D) 6.4 m

ANSWER= (D)
Explain:- 6.4 meter is the minimum clearance provided for the 132 kV line from the ground.

 

136. If a 132 kV line passes over a residential building, what shall be the minimum vertical clearance from the roof of the building?

A) 4.57 m
B) 3 m
C) 6.38 m
D) 9.27 m

ANSWER= (A)
Explain:- If a 132 kV line passes over a residential building, 4.57 meter shall be the minimum vertical clearance from the roof of the building.

 

137. What is the minimum horizontal clearance of a LV line from a residential building?

A) 1.6 m
B) 1.2 m
C) 0.9 m
D) 0.6 m

ANSWER= (B)
Explain:- 1.2 meter is the minimum horizontal clearance of a LV line from a residential building.

 

138. What is the minimum clearance of HV lines from ground across the streets?

A) 3 m
B) 5 m
C) 8 m
D) 6 m

ANSWER= (D)
Explain:- 6 meter is the minimum clearance of HV lines from ground across the streets.

 

139. In a distribution system, which of the following items shares the major cost?

A) Conductors
B) Insulators
C) Distribution Transformers
D) Poles

ANSWER= (C)
Explain:- In a distribution system, Distribution Transformer shares the major cost.

 

140. The following materials of line conductor are given 

i. Hard drawn copper 

ii. Cadmium copper 

iii. Aluminium 

iv. Galvanized steel 

What is the correct series in descending order of their electrical conductivities?

A) i, ii, iv, iii
B) ii, i, iv, iii
C) ii, i, iii, iv
D) i, ii, iii, iv

ANSWER= (D)
Explain:- Option D is correct.

 

141. The most ideal material for the over head conductor is copper. What are the advantages of this?

A) The price of copper is less
B) Smaller cross sectional area
C) Area offered by the wind loads is reduced
D) Both B and C

ANSWER= (D)
Explain:- Option D is correct.

 

142. Which among these properties are not suitable for the conductor material?

A) High electrical conductivity
B) High tensile strength
C) High specific gravity
D) Lower cost

ANSWER= (C)
Explain:- High specific gravity property is not suitable for the conductor material.

 

143. Which among these is not the component of over head transmission lines?

A) Transformers
B) Cross arms
C) Conductors
D) Danger plates

ANSWER= (A)
Explain:- Transformer is not the component of overhead transmission line.

 

144. Which among the following properties has got a higher value for aluminium in comparison to that of copper?

A) Melting point
B) Electrical resistivity
C) Specific gravity
D) Thermal conductivity

ANSWER= (B)
Explain:- Electrical resistivity has got a higher value for aluminium in comparison to that of copper.

 

145. Why are galvanised steel conductors not suitable for transmitting large power over long distance?

A) Poor conductivity
B) More power loss
C) High resistance of steel
D) Both A and C

ANSWER= (D)
Explain:- Option D is correct.

 

146. Which material is used for the manufacture of ground wire?

A) Galvanised steel
B) Aluminium
C) Stainless steel
D) Cast iron

ANSWER= (A)
Explain:- Galvanised steel is used for the manufacture of ground wire.

 

147. When steel is reinforced what happens to the composite conductor?

A) 25 % more compared with equivalent weight of copper
B) 25 % less compared with equivalent weight of copper
C) 35 % more compared with equivalent weight of copper
D) 35 % less compared with equivalent weight of copper

ANSWER= (B)
Explain:- Option B is correct.

 

148. Why is A.C.S.R conductor used as the replacement or substitute for copper?

A) Economy
B) Higher current carrying capacity
C) Higher tensile strength
D) Being less weight

ANSWER= (A)
Explain:- A.C.S.R conductor is used as the replacement or substitute for copper because of economy.

 

149. What is the function of steel wire in A.C.S.R conductors?

A) Takes care of surges
B) Compensate for skin effect
C) Provide additional mechanical strength
D) Reduce capacitance and inductance

ANSWER= (C)
Explain:- The function of steel wire in A.C.S.R conductor is to provide additional mechanical strength.

 

150. Why is grease added between steel and aluminium conductors?

A) To reduce friction between the strand
B) To reduce the corrosion by electrolytic action
C) To reduce the leakage of current
D) To eliminate the air gaps

ANSWER= (B)
Explain:- The grease is added between steel and aluminium conductors to reduce the corrosion by electrolytic action.

 

151. What is the general ratio of the cross sectional area of the two metals used in the A.C.S.R conductors?

A) 4 : 3
B) 1 : 8
C) 2 : 1
D) 1 : 4

ANSWER= (D)
Explain:- The general ratio of the cross sectional area of the two metals used in the A.C.S.R conductors is 1 : 4.

 

152. What is the empirical formula to calculate the number of strands?

A) 3n (n+2n) + 2
B) 3n (n+1) + 2
C) 3n (n+1) + 1
D) 3n (3+ 3n) + 1

ANSWER= (C)
Explain:- Number of strands = 3n (n+1) + 1.

 

153. What is the main drawback of overhead system over underground system?

A) High initial cost
B) Surge problem
C) Underground system is more flexible than overhead system
D) Higher charging current

ANSWER= (B)
Explain:- The main drawback of overhead system over underground system is Surge problem.

 

154. Galvanised steel wire is generally used as

A) Earth wire
B) Structural components
C) Stay wire
D) All of these

ANSWER= (D)
Explain:- All are correct.

 

155. For aluminium, as compared to copper, all the following factors have higher values except

A) Electrical conductivity
B) Specific volume
C) Resistance per unit length for same cross-section
D) Co-efficient of linear expansion

ANSWER= (A)
Explain:- Option A is correct.

 

156. The steel used in steel cored conductors is usually

A) High speed steel
B) Stainless steel
C) Alloy steel
D) Mild steel

ANSWER= (D)
Explain:- The steel used in steel cored conductors is usually Mild steel.

 

157. Which of the following materials is used for overhead transmission lines?

A) Steel cored aluminium
B) Galvanised steel
C) Cadmium copper
D) Any of the above

ANSWER= (D)
Explain:- Option D is correct.

 

158. The conductors of the overhead lines are

A) Stranded
B) Solid
C) Both A and B
D) None of the above

ANSWER= (C)
Explain:- Option C is correct.

 

159. The power transmitted will be maximum when

A) Sending end voltage is more
B) Receiving end voltage is more
C) Corona losses are minimum
D) Reactance is high

ANSWER= (A)
Explain:- The power transmitted will be maximum when sending end voltage is more.

 

160. Which of the following materials is not used for transmission and distribution of electrical power?

A) Aluminium
B) Steel
C) Copper
D) Tungsten

ANSWER= (D)
Explain:- Tungsten material is not used for transmission and distribution of electrical power.

 

161. Overhead lines generally use

A) Copper conductors
B) All Aluminium conductors
C) A.C.S.R. conductors
D) Tungsten conductors

ANSWER= (C)
Explain:- Overhead lines generally use A.C.S.R. conductors.

 

162. In AC.S.R. conductors, the insulation between aluminium and steel conductors is

A) Insulin
B) Bitumen
C) Varnish
D) No insulation is required

ANSWER= (D)
Explain:- No insulation is required in AC.S.R. conductors between aluminium and steel conductors. .

 

163. In aluminium conductors, steel core is provided to

A) Neutralize proximity effect
B) Compensate for skin effect
C) Increase the tensile strength
D) Reduce line inductance

ANSWER= (C)
Explain:- In aluminium conductors, steel core is provided to increase the tensile strength.

 

164. Stranded conductors are used for transmitting power at high voltages because of

A) Low cost
B) Ease-in handling
C) Better wind resistance
D) Increased tensile strength

ANSWER= (B)
Explain:- Stranded conductors are used for transmitting power at high voltages because of ease-in handling.

 

165. Stranded conductors are used for transmitting power at high voltages because of

A) 2
B) 1
C) 0.5
D) 1.5

ANSWER= (A)
Explain:- For the same resistance of line the ratio of weight of copper conductor/ weight of aluminium conductor is 2.

 

166. A 70/6 ACSR conductor is an aluminium conductor steel reinforced, having

A) Cross-sectional area of steel as 70 mm^2 and the cross-sections area of aluminium as 6 mm^2
B) Cross sectional area of aluminium as 70 mm^2 and the cross-sectional area of steel as 6 mm^2
C) 70 steel conductors and 6 aluminium conductors
D) 70 aluminium conductors and 6 steel conductors

ANSWER= (D)
Explain:- A 70/6 ACSR conductor is an aluminium conductor steel reinforced, having 70 aluminium conductors and 6 steel conductors.

 

167. ACSR conductor having 7 steel stands surrounded by 25 aluminum conductor will be specified as

A) 7/32
B) 7/25
C) 25/7
D) 32/7

ANSWER= (C)
Explain:- ACSR conductor having 7 steel stands surrounded by 25 aluminum conductor will be specified as 25/7.

 

168. Aluminium is being favored as bus-bar material mainly because of

A) Low density
B) Low cost
C) Case of fabrication
D) Non availability of copper

ANSWER= (B)
Explain:- Aluminium is being favored as bus-bar material mainly because of low cost.

 

169. Which type of copper wire will have highest tensile strength?

A) Medium drawn
B) Soft drawn
C) Hard drawn
D) None of these

ANSWER= (C)
Explain:- Hard drawn copper wire will have highest tensile strength.

 

170. While deciding an efficient and economical transmission and distribution system, the preferred distribution system will be

A) Three phase, 3 wire
B) Three phase, 4 wire
C) Single phase, 2 wire
D) Two phase, 3 wire

ANSWER= (B)
Explain:- While deciding an efficient and economical transmission and distribution system, the preferred distribution system will be three phase, 4 wire.

 

171. The volume of copper required in a transmission system is proportional to

A) Voltage
B) Power factor
C) Both voltage and power factor
D) Current

ANSWER= (C)
Explain:- The volume of copper required in a transmission system is proportional to voltage and power factor.

 

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

A) Current capacity
B) Voltage drop
C) Operating voltage
D) All of the above

ANSWER= (A)
Explain:- One would design the feeders of the transmission system based on its Current capacity.

 

173. One would design the distributors of the distribution system based on its

A) Current capacity
B) Voltage drop
C) Operating frequency
D) All of the above

ANSWER= (B)
Explain:- One would design the distributors of the distribution system based on its voltage drop in it.

 

174. In a transmission line system, the feeders act as input to

A) Distributors
B) Service mains
C) Transformer substations
D) All of the above

ANSWER= (A)
Explain:- In a transmission line system, the feeders act as input to distributors.

 

175. In emergency cases, another wire is installed in the system, that is widely known as

A) Neutral wire
B) Line wire
C) Guy wire
D) Earth wire

ANSWER= (C)
Explain:- In emergency cases, another wire is installed in the system, that is widely known as Guy wire.

 

176. Before installing any transmission system, one has to decide about the type of the transmission system to be employed. Considering a monetary shortage and economical setup, one would take up

A) Overhead system
B) Underground system
C) Underground or Overhead system
D) Can be chosen randomly

ANSWER= (A)
Explain:- Before installing any transmission system, one has to decide about the type of the transmission system to be employed. Considering a monetary shortage and economical setup, one would take up overhead system.

 

177. The underground transmission and distribution of power is better than the corresponding overhead transmission and distribution in

A) Appearance and Safety
B) Frequency of faults
C) Maintenance cost
D) Appearance, Safety, Maintenance, Frequency of faults

ANSWER= (D)
Explain:- The underground transmission and distribution of power is better than the corresponding overhead transmission and distribution in appearance, safety, maintenance, frequency.

 

178. The usual spans with R.C.C. poles are

A) 40 - 50 metres
B) 60 - 100 metres
C) 80 - 100 metres
D) 300 - 500 metres

ANSWER= (C)
Explain:- The usual spans with R.C.C. poles are 80 - 100 metres.

 

179. The wooden poles well impregnated with creosite oil or any preservative compound have life from

A) 2 to 5 years
B) 10 to 12 years
C) 25 to 30 years
D) 70 to 80 years

ANSWER= (C)
Explain:- The wooden poles well impregnated with creosite oil or any preservative compound have life from 25 to 30 years.

 

180. Transmission voltage of 11 kV is normally used for distances upto

A) 20 - 25 km
B) 40 - 50 km
C) 60 - 70 km
D) 80 - 100 km

ANSWER= (A)
Explain:- Transmission voltage of 11 kV is normally used for distances upto 20 - 25 km.

 

181. Transmission voltage of 11 kV is normally used for distances upto

A) 20 - 25 km
B) 40 - 50 km
C) 60 - 70 km
D) 80 - 100 km

ANSWER= (A)
Explain:- Transmission voltage of 11 kV is normally used for distances upto 20 - 25 km.

 

182. Wooden poles for supporting transmission lines are used for voltages up to

A) 440 V
B) 11 kV
C) 1.1 kV
D) 22 kV

ANSWER= (D)
Explain:- Wooden poles for supporting transmission lines are used for voltages up to 22 kV.

 

183. When transformers or switchgears are to be installed in a transmission line, the poles used are

A) I type
B) J type
C) H type
D) L type

ANSWER= (C)
Explain:- When transformers or switchgears are to be installed in a transmission line, the poles used are H type.

 

184. The disadvantage of transmission lines as compared to cables is

A) Exposure to atmospheric hazards like smoke, ice, etc
B) Exposure to lightening
C) Inductive interference between power and communication circuits
D) All of the above

ANSWER= (D)
Explain:- Option D is correct.

 

185. When the power is to be transmitted over a distance of 500 km, the transmission voltage should be in the range

A) 150kV - 220kV
B) 33 kV - 66 kV
C) 66 kV - 100 kV
D) 110 kV - 150 kV

ANSWER= (A)
Explain:- When the power is to be transmitted over a distance of 500 km, the transmission voltage should be in the range 150kV - 220kV.

 

186. If 3000 kW power is to be transmitted over a distance of 30 km, the desirable transmission voltage will be

A) 11 kV
B) 33 kV
C) 132 kV
D) 220 kV

ANSWER= (B)
Explain:- If 3000 kW power is to be transmitted over a distance of 30 km, the desirable transmission voltage will be 33kV.

 

187. The most economic voltage for transmitting given power over a known distance by overhead transmission line is approximately

A) 3.6 kV/km
B) 0.6 kV/km
C) 1.6 kV/km
D) 2.6 kV/km

ANSWER= (B)
Explain:- The most economic voltage for transmitting given power over a known distance by overhead transmission line is approximately 0.6 kV/km.

 

188. Steel poles for transmission lines need protection against

A) Termites
B) Borer
C) Corrosion
D) All of the above

ANSWER= (C)
Explain:- Steel poles for transmission lines need protection against Corrosion.

 

189. Guy wire is used to

A) Support the pole
B) Provide protection against surges
C) Provide emergency earth route
D) Protect conductors against short circuiting

ANSWER= (A)
Explain:- Guy wire is used to support the pole.

 

190. High voltage transmission lines use

A) Pin insulators
B) Suspension insulators
C) Both A and B
D) None of these

ANSWER= (B)
Explain:- High voltage transmission lines use suspension insulators.

 

191. Distribution lines in India generally use

A) R.C.C. poles
B) Wooden poles
C) Steel towers
D) None of these

ANSWER= (A)
Explain:- Distribution lines in India generally use R.C.C. poles.

 

192. In transmission lines the cross-arms are made of

A) R.C.C.
B) Wood
C) Steel
D) Copper

ANSWER= (C)
Explain:- In transmission lines the cross-arms are made of Steel.

 

193. The use of strain type insulators is made where the conductors are

A) Dead ended
B) At intermediate anchor towers
C) Both A and B
D) None of the above

ANSWER= (C)
Explain:- Option C is correct .

 

194. Pin type insulators are generally not used for voltages beyond

A) 11 kV
B) 33 kV
C) 132 kV
D) 66 kV

ANSWER= (B)
Explain:- Pin type insulators are generally not used for voltages beyond 33 kV.

 

195. For transmission of power over a distance of 200 km, the transmission voltage should be

A) 11 kV
B) 33 kV
C) 132 kV
D) 66 kV

ANSWER= (C)
Explain:- For transmission of power over a distance of 200 km, the transmission voltage should be 132 kV.

 

196. What is the main purpose for guy wire?

A) Provides emergency earth route
B) Supports the pole
C) Protects against the surges
D) All of these

ANSWER= (B)
Explain:- The main purpose for guy wire is to support the pole.

 

197. What is the usual span of the RCC poles?

A) 250 – 400 metre
B) 80 – 150 metre
C) 50 – 105 metre
D) 10 – 75 metre

ANSWER= (B)
Explain:- The usual span of the RCC poles are 80 – 150 metre.

 

198. Which among these is not a type of steel poles?

A) Rolled steel joints
B) Rail poles
C) Tubular poles
D) None of these

ANSWER= (D)
Explain:- Option D is correct.

 

199. Steel poles are painted so as to prevent it from-----

A) Termites
B) Borer
C) Corrosion
D) All of these

ANSWER= (C)
Explain:- Steel poles are painted so as to prevent it from Corrosion.

 

200. To prevent rotting oil the wooden poles which oil is impregnated to it ?

A) Creosote oil
B) Kerosene oil
C) Mineral oil
D) All of these

ANSWER= (A)
Explain:- To prevent rotting oil the wooden poles Creosote oil is impregnated to it.

 

201. Which among these are the properties for the line supports?

A) Higher mechanical strength
B) Light in weight
C) Easy accessibility of conductors for maintenance
D) All of these

ANSWER= (D)
Explain:- Option D is correct.

 

202. In India, which types of poles are commonly used for distribution?

A) RCC poles
B) Wooden poles
C) Steel poles
D) Both A and C

ANSWER= (D)
Explain:- Option D is correct.

 

203. For high voltage transmission lines, why are conductors suspended from towers?

A) Reduce clearance from ground
B) Increase the clearance from ground
C) Reduce the environmental effects
D) Take care of increase in length

ANSWER= (B)
Explain:- For high voltage transmission lines, the conductors are suspended from towers to increase the clearance from ground.