1. Which of the following is not the transmission voltage in America ?
(A) 66 kV
(B) l32kV
(C) 264 kV
(D) 400 kV
C
2. Which of the following is usually not the generating voltage ?
(A) 6.6 kV
(B) 9.9 kV
(C) 11kV
(D) 13.2 kV.
B
3. Boosters are basically
(A) inductors
(B) capacitors
(C) transformers
(D) synchronous motors.
C
4. Which of the following is not the distribution system normally used
(A) 3 phase-4 wire
(B) 3 phase-3 wire
(C) Single phase - 3 wire
(D) Single phase -4 wire.
D
5. Conductors for high voltage transmission lines are suspended from towers
(A) to reduce clearance from ground
(B) to increase clearance from ground
(C) to reduce wind and snow loads
(D) to take care of extension in length during summer.
B
6. Transmission efficiency increases as
(A) voltage and power factor both increase
(B) voltage and power factor both decrease
(C) voltage increases but power factor decreases
(D) voltage decreases but power factor increases.
A
7. With same maximum voltage to earth, which ac system (with p.f. 0.8) will require more copper as compared to dc 2 wire system
(A) single phase. 2 wire (mid point earthed)
(B) single phase. 3 wire (neutral=1/2 outer)
(C) three phase three wire
(D) three phase-four wire (neutral = outer).
D
8. When alternating current passes through a conductor
(A) it remains uniformly distributed throughout the section of conductor
(B) portion of conductor near the surface carries more current as compared to the core
(C) portion of conductor near the surface carries less current as compared to the core
(D) entire current passes through the core of the conductor.
B
9. The fact that a conductor carries more current on the surface as compared to core, is known as
(A) skin effect
(B) corona
(C) permeability
(D) unsymmetrical fault.
A
10. The effective resistance of a conductor will be the same as ohmic resistance when
(A) current is in true sine wave form
(B) voltage is low
(C) power factor is unity
(D) Current is uniformly distributed in the conductor cross-section.
D
11. Skin effect results in
(A) reduced effective resistance but increased effective internal reactance of the conductor
(B) increased effective resistance but reduced effective internal reactance of. the conductor
(C) reduced effective resistance as well as effective internal reactance
(D) increased effective resistance as well as effective internal reactance.
B
12. Skin effect depends on
(A) size of the conductor
(B) frequency of the current
(C) resistivity of the conductor material
(D) all of the above.
D
13. The skin effect of a conductor will reduce as the
(A) diameter increases
(B) frequency increases
(C) permeability of conductor material increases
(D) resistivity of conductor material increases.
D
14. Skin effect is proportional to
(A) diameter of conductor
(B) (diameter of conductor)1/2
(C) (diameter of conductor )2
(D) (diameter of conductor )2.
C
15. In overhead transmission lines the effect of capacitance can be neglected when the length of line is less than
(A) 200 km
(B) 160 km
(C) 100 km
(D) 80 km.
D
16. For constant voltage transmission the voltage drop is compensated by installing
(A) synchronous motors
(B) capacitors
(C) inductors
(D) all of the above.
17. The disadvantage of constant voltage transmission is
(A) short circuit current of the system is increased
(B) load power factor in heavy loads
(C) large conductor area is required for same power transmission
(D) air of the above.
18. The surge impedance for over head line is taken as
(A) 10-20 ohms
(B) 50-60 ohms
(C) 100-200 ohms
(D) 1000-2000 ohms.
19. Pin insulators are normally used up to voltage of about
(A)100kV
(B) 66 kV
(C) 33 kV
(D) 25 kV.
20. Strain type insulator arc used where the conductors arc
(A) dead ended
(B) at intermediate anchor towers
(C) any of the above
(D) none of the above.
21. For 66 kV lines the number of insulator discs used are
(A) 3
(B) 5
(C) 8
(D) 12.
22. Ten discs usually suggest that the transmission line voltage is
(A) 11 kV
(B) 33 kV
(C) 66 kV
(D) 132 kV.
23. The effect of corona is
(A) increased energy loss
(B) increased reactance
(C) increased inductance
(D) all of the above.
24. Corona usually occurs when the electrostatic stress in the air around the conductor succeeds
(A) 30 kV (maximum value)/cm
(B) 22 kV (maximum value)/cm
(C) 11 kV (rms value)/cm
(D) 6.6 kv (rms value)/cm.
25. Corona effect can be detected by
(A) hissing sound
(B) faint luminous flow of bluish color
(C) presence of ozone detected by odor
(D) all of the above.
26. The current drawn by the line due to corona losses is
(A) sinusoidal
(B) square
(C) non-sinusoidal
27. Presence of ozone as a result of corona is harmful because
(A) it gives bad odor
(B) it corrodes the material
(C) it transfers energy to the ground
(D) reduces power factor.
28. Between two supports, due to sag the conductor takes the form of
(A) catenary
(B) triangle
(C) ellipse
(D) semi-circle.
29. The inductance of a single phase two wire line is given by (D is the distance between conductors and 2v is the diameter of conductor)
(A) 0.4 loge (D/r) mH/km
(B) 0.55 loge (D/r) mH/km
(C) 0.4 loge (r/D) mH/km
(D) 0.55 loge (r/D) mH/km.
30. The effect of ice deposition on conductor is
(A) increased skin effect
(B) reduced corona losses
(C) increased weight
(D) reduced sag.
(A) synchronous motors
(B) capacitors
(C) inductors
(D) all of the above.
A
17. The disadvantage of constant voltage transmission is
(A) short circuit current of the system is increased
(B) load power factor in heavy loads
(C) large conductor area is required for same power transmission
(D) air of the above.
A
18. The surge impedance for over head line is taken as
(A) 10-20 ohms
(B) 50-60 ohms
(C) 100-200 ohms
(D) 1000-2000 ohms.
C
19. Pin insulators are normally used up to voltage of about
(A)100kV
(B) 66 kV
(C) 33 kV
(D) 25 kV.
D
20. Strain type insulator arc used where the conductors arc
(A) dead ended
(B) at intermediate anchor towers
(C) any of the above
(D) none of the above.
C
21. For 66 kV lines the number of insulator discs used are
(A) 3
(B) 5
(C) 8
(D) 12.
B
22. Ten discs usually suggest that the transmission line voltage is
(A) 11 kV
(B) 33 kV
(C) 66 kV
(D) 132 kV.
D
23. The effect of corona is
(A) increased energy loss
(B) increased reactance
(C) increased inductance
(D) all of the above.
A
24. Corona usually occurs when the electrostatic stress in the air around the conductor succeeds
(A) 30 kV (maximum value)/cm
(B) 22 kV (maximum value)/cm
(C) 11 kV (rms value)/cm
(D) 6.6 kv (rms value)/cm.
A
25. Corona effect can be detected by
(A) hissing sound
(B) faint luminous flow of bluish color
(C) presence of ozone detected by odor
(D) all of the above.
D
26. The current drawn by the line due to corona losses is
(A) sinusoidal
(B) square
(C) non-sinusoidal
C
27. Presence of ozone as a result of corona is harmful because
(A) it gives bad odor
(B) it corrodes the material
(C) it transfers energy to the ground
(D) reduces power factor.
B
28. Between two supports, due to sag the conductor takes the form of
(A) catenary
(B) triangle
(C) ellipse
(D) semi-circle.
A
29. The inductance of a single phase two wire line is given by (D is the distance between conductors and 2v is the diameter of conductor)
(A) 0.4 loge (D/r) mH/km
(B) 0.55 loge (D/r) mH/km
(C) 0.4 loge (r/D) mH/km
(D) 0.55 loge (r/D) mH/km.
A
30. The effect of ice deposition on conductor is
(A) increased skin effect
(B) reduced corona losses
(C) increased weight
(D) reduced sag.
C
31. The effect of wind pressure is more predominant on
(A) transmission lines
(B) neutral wires
(C) insulator
(D) supporting towers.
32. Which of the following statement is correct ?
(A) Wind pressure reduces corona effects
(B) Ice on conductors improves power factor
(C) Wind pressure is taken to act in a direction at right angles to that for ice
(D) Wind pressure and ice on conductors together improve regulation of power transmitted.
33. Which of the following statements is incorrect ?
(A) As the temperature rises the tension in the transmission line decreases
(B) As temperature rises the sag in transmission lines reduces
(C) Tension and sag in transmission lines are complementary to each other.
34. Wooden poles for supporting transmission lines are used for voltages up to
(A) 440 V
(B)11 kV
(C) 22 kV
(D) 66 kV.
35. 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 cosf
(C) k/ cos2f
(D) 2k/ cos2p
36. Maximum permissible span for wooden poles is
(A) 10 meter
(B) 20 meters
(C) 60 meters
(D) 200 meters.
37. 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.
38. For improving life, steel poles are galvanized. Galvanizing is the process of applying a layer of
(A) paint
(B) varnish
(C) tar coal
(D) zinc.
39. The disadvantage of transmission lines as compared to cables is
(A) exposure to lightening
(B) exposure to atmospheric hazards like smoke, ice, etc.
(C) inductive interference between power and communication circuits
(D) all of the above.
40. ACSR conductor implies
(A) All conductors surface treated and realigned
(B) Aluminum conductor steel reinforced
(C) Anode current sinusoidally run
(D) Anodized Core Smooth Run.
41. The surge resistance of transmission lines is about
(A) 50 ohms
(B) 100 ohms
(C) 250 ohms
(D) 500 ohms.
42. During storm the live conductor of public electric supply breaks down and touches the earth. The consequences will be
(A) supply voltage will drop
(B) supply voltage will increase
(C) current will flow to earth
(D) no current will flow in the conductor.
43. In transmission system a feeder feeds power to
(A) service mains
(B) generating stations
(C) distributors
(D) all of the above.
44. For transmission lines the standing wave ratio is the ratio of
(A) maximum voltage to minimum voltage
(B) maximum current to minimum voltage
(C) peak voltage to rms voltage
(D) maximum reactance to minimum reactance.
45. In a transmission line following arc the distributed constants
(A) resistance and inductance only
(B) resistance, inductance and capacitance
(C) resistance, inductance, capacitance and short conductance.
(A) transmission lines
(B) neutral wires
(C) insulator
(D) supporting towers.
D
32. Which of the following statement is correct ?
(A) Wind pressure reduces corona effects
(B) Ice on conductors improves power factor
(C) Wind pressure is taken to act in a direction at right angles to that for ice
(D) Wind pressure and ice on conductors together improve regulation of power transmitted.
C
33. Which of the following statements is incorrect ?
(A) As the temperature rises the tension in the transmission line decreases
(B) As temperature rises the sag in transmission lines reduces
(C) Tension and sag in transmission lines are complementary to each other.
C
34. Wooden poles for supporting transmission lines are used for voltages up to
(A) 440 V
(B)11 kV
(C) 22 kV
(D) 66 kV.
C
35. 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 cosf
(C) k/ cos2f
(D) 2k/ cos2p
D
36. Maximum permissible span for wooden poles is
(A) 10 meter
(B) 20 meters
(C) 60 meters
(D) 200 meters.
C
37. 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.
C
38. For improving life, steel poles are galvanized. Galvanizing is the process of applying a layer of
(A) paint
(B) varnish
(C) tar coal
(D) zinc.
D
39. The disadvantage of transmission lines as compared to cables is
(A) exposure to lightening
(B) exposure to atmospheric hazards like smoke, ice, etc.
(C) inductive interference between power and communication circuits
(D) all of the above.
D
40. ACSR conductor implies
(A) All conductors surface treated and realigned
(B) Aluminum conductor steel reinforced
(C) Anode current sinusoidally run
(D) Anodized Core Smooth Run.
B
41. The surge resistance of transmission lines is about
(A) 50 ohms
(B) 100 ohms
(C) 250 ohms
(D) 500 ohms.
D
42. During storm the live conductor of public electric supply breaks down and touches the earth. The consequences will be
(A) supply voltage will drop
(B) supply voltage will increase
(C) current will flow to earth
(D) no current will flow in the conductor.
C
43. In transmission system a feeder feeds power to
(A) service mains
(B) generating stations
(C) distributors
(D) all of the above.
C
44. For transmission lines the standing wave ratio is the ratio of
(A) maximum voltage to minimum voltage
(B) maximum current to minimum voltage
(C) peak voltage to rms voltage
(D) maximum reactance to minimum reactance.
A
45. In a transmission line following arc the distributed constants
(A) resistance and inductance only
(B) resistance, inductance and capacitance
(C) resistance, inductance, capacitance and short conductance.
C
46. The bundling of conductors is done primarily to
(A) reduce reactance
(B) increase reactance
(C) increase ratio interference
(D) reduce radio interference.
47. Which of the following regulation is considered to be the best
(A) 2%
(B) 30%
(C)70%
(D) 98%.
48. The characteristic impedance of a transmission line depends upon
(A) shape of the conductor
(B) surface treatment of the conductors
(C) conductivity of the material
(D) geometrical configuration. of the conductors.
49. For a distortion-less transmission line (G = shunt conductance between two wires)
(A) R/L = G/C
(B) RL=GC
(C) RG=LC
(D)RLGC=0
50. Guard ring transmission line
(A) improves power factor
(B) reduces earth capacitance of the lowest unit
(C) reduces transmission losses
(D) improves regulation.
51. When the power is to be transmitted over a distance of 500 km, the transmission voltage should be in the range
(A) 33 kV - 66 kV
(B) 66 kV - 100 kV
(C) 110 kV - 150 kV
(D) 150kV - 220kV.
52. A relay used on long transmission lines is
(A) mho's relay
(B) reactance relay
(C) impedance relay
(D) no relay is used.
53. Total load transmitted through a 3 phase transmission line is 10,000 kW at 0.8 power factor lagging. The I2R losses are 900 kW. The efficiency of transmission line is
(A) 60%
(B) 90%
(C) 95%
(D) 99%.
54. Litz wires are used for intermediate frequencies.to overcome
(A) corona effect
(B) skin effect
(C) radio interference
(D) all of the above.
55. In order to reduce skin effect at UHF
(A) conductors are painted
(B) conductors are anodized
(C) copper lubes with silver plating are used
(D) copper rods with silver plating are used.
56. Shunt capacitance is usually neglected in the analysis of
(A) Short transmission lines
(B) Medium transmission lines
(C) Long transmission lines
(D) Medium as well as long transmission lines.
57. The chances of corona are maximum during
(A) summer heat
(B) winter
(C) dry weather
(D) humid weather.
58. The power transmitted will be maximum when
(A) Sending end voltage is more
(B) Receiving end voltage is more
(C) Reactance is high
(D) Corona losses are least.
59. 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) half
(D) one fourth.
60. When two conductors each of radius r are at a distance D, the capacitance between the two is proportional to
(A) loge (D/r)
(B) loge (r/D)
(C) 1/loge (D/r)
(D) 1/loge (r/D).
(A) reduce reactance
(B) increase reactance
(C) increase ratio interference
(D) reduce radio interference.
A
47. Which of the following regulation is considered to be the best
(A) 2%
(B) 30%
(C)70%
(D) 98%.
A
48. The characteristic impedance of a transmission line depends upon
(A) shape of the conductor
(B) surface treatment of the conductors
(C) conductivity of the material
(D) geometrical configuration. of the conductors.
D
49. For a distortion-less transmission line (G = shunt conductance between two wires)
(A) R/L = G/C
(B) RL=GC
(C) RG=LC
(D)RLGC=0
A
50. Guard ring transmission line
(A) improves power factor
(B) reduces earth capacitance of the lowest unit
(C) reduces transmission losses
(D) improves regulation.
B
51. When the power is to be transmitted over a distance of 500 km, the transmission voltage should be in the range
(A) 33 kV - 66 kV
(B) 66 kV - 100 kV
(C) 110 kV - 150 kV
(D) 150kV - 220kV.
D
52. A relay used on long transmission lines is
(A) mho's relay
(B) reactance relay
(C) impedance relay
(D) no relay is used.
A
53. Total load transmitted through a 3 phase transmission line is 10,000 kW at 0.8 power factor lagging. The I2R losses are 900 kW. The efficiency of transmission line is
(A) 60%
(B) 90%
(C) 95%
(D) 99%.
B
54. Litz wires are used for intermediate frequencies.to overcome
(A) corona effect
(B) skin effect
(C) radio interference
(D) all of the above.
B
55. In order to reduce skin effect at UHF
(A) conductors are painted
(B) conductors are anodized
(C) copper lubes with silver plating are used
(D) copper rods with silver plating are used.
C
56. Shunt capacitance is usually neglected in the analysis of
(A) Short transmission lines
(B) Medium transmission lines
(C) Long transmission lines
(D) Medium as well as long transmission lines.
A
57. The chances of corona are maximum during
(A) summer heat
(B) winter
(C) dry weather
(D) humid weather.
D
58. The power transmitted will be maximum when
(A) Sending end voltage is more
(B) Receiving end voltage is more
(C) Reactance is high
(D) Corona losses are least.
A
59. 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) half
(D) one fourth.
D
60. When two conductors each of radius r are at a distance D, the capacitance between the two is proportional to
(A) loge (D/r)
(B) loge (r/D)
(C) 1/loge (D/r)
(D) 1/loge (r/D).
C
61. In a transmission line having negligible resistance the surge impedance is
(A) (L+C)1/2
(B) (C/L)1/2
(C) (1/LC)1/2
(D) (L/C)1/2
62. A relay used on short transmission lines is
(A) Reactance relay
(B) Mho's relay
(C) Impedance relay
(D) None of the above.
63. In case the characteristic impedance of the line is equal to the load impedance
(A) all the energy will pass to the earth
(B) all the energy will be lost in transmission losses
(C) the system will resonate badly
(D) all the energy sent will be absorbed by the load.
64. For a properly terminated line
(A) ZR=ZO
(B) Z/R > ZO
(C) ZR < ZO
(D) ZR =Z0 = 0.
65. The dielectric strength of air at 250C and 76 cm/Hg is
(A) 1 kV/cm
(B) 1 kV/mm
(C) 3 kV/cm
(D) 30 kV/cm.
66. The chances of corona are maximum in
(A) domestic wiring
(B) distribution lines
(C) transmission lines
(D) all of the above.
67. Transmission lines link
(A) service points to consumer premises
(B) distribution transformer to consumer premises
(C) receiving end station to distribution transformer
(D) generating station to receiving end station.
68. In case of open circuit transmission lines the reflection coefficient is
(A) 1
(B) 0.5
(C) -1
(D) Zero.
69. Impedance relay is used on
(A) Short transmission lines
(B) Medium transmission lines
(C) Long transmission line
(D) All the transmission lines.
70. Which type of insulators are used on 132 kV transmission lines ?
(A) Pin type
(B) Disc type
(C) Shackle type
(D) Pin and shackle type.
71. String efficiency can be improved by
(A) using Longer cross arm
(B) grading the insulator
(C) using a guard ring
(D) any of the above.
72. Minimum horizontal clearance of a low voltage transmission line from residential buildings must be
(A) 11/2 feet
(B) 3 feet
(C) 4 feet
(D) 8 feet.
73. 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) 12 feet
(C) 13 feet
(D) 16 feet.
74. Alternating current power is transmitted at high voltage
(A) to safeguard against pilferage
(B) to minimize transmission losses
(C) to reduce cost of generation
(D) to make the system reliable.
75. Stranded conductors arc used for transmitting, power at high voltages because of
(A) increased tensile strength
(B) better wind resistance
(C) ease-in handling
(D) low cost.
(A) (L+C)1/2
(B) (C/L)1/2
(C) (1/LC)1/2
(D) (L/C)1/2
D
62. A relay used on short transmission lines is
(A) Reactance relay
(B) Mho's relay
(C) Impedance relay
(D) None of the above.
A
63. In case the characteristic impedance of the line is equal to the load impedance
(A) all the energy will pass to the earth
(B) all the energy will be lost in transmission losses
(C) the system will resonate badly
(D) all the energy sent will be absorbed by the load.
D
64. For a properly terminated line
(A) ZR=ZO
(B) Z/R > ZO
(C) ZR < ZO
(D) ZR =Z0 = 0.
D
65. The dielectric strength of air at 250C and 76 cm/Hg is
(A) 1 kV/cm
(B) 1 kV/mm
(C) 3 kV/cm
(D) 30 kV/cm.
D
66. The chances of corona are maximum in
(A) domestic wiring
(B) distribution lines
(C) transmission lines
(D) all of the above.
C
67. Transmission lines link
(A) service points to consumer premises
(B) distribution transformer to consumer premises
(C) receiving end station to distribution transformer
(D) generating station to receiving end station.
D
68. In case of open circuit transmission lines the reflection coefficient is
(A) 1
(B) 0.5
(C) -1
(D) Zero.
D
69. Impedance relay is used on
(A) Short transmission lines
(B) Medium transmission lines
(C) Long transmission line
(D) All the transmission lines.
B
70. Which type of insulators are used on 132 kV transmission lines ?
(A) Pin type
(B) Disc type
(C) Shackle type
(D) Pin and shackle type.
B
71. String efficiency can be improved by
(A) using Longer cross arm
(B) grading the insulator
(C) using a guard ring
(D) any of the above.
D
72. Minimum horizontal clearance of a low voltage transmission line from residential buildings must be
(A) 11/2 feet
(B) 3 feet
(C) 4 feet
(D) 8 feet.
C
73. 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) 12 feet
(C) 13 feet
(D) 16 feet.
C
74. Alternating current power is transmitted at high voltage
(A) to safeguard against pilferage
(B) to minimize transmission losses
(C) to reduce cost of generation
(D) to make the system reliable.
B
75. Stranded conductors arc used for transmitting, power at high voltages because of
(A) increased tensile strength
(B) better wind resistance
(C) ease-in handling
(D) low cost.
C
76. For the same resistance of line the ratio, weight of copper conductor/ weight of aluminium conductor , is
(A) 0.50
(B) 0.75
(C) 1.50
(D) 2.0.
77. The function of steel wire in a ACSR conductor is
(A) to take care of surges
(B) to prevent corona
(C) to reduce inductance and hence improve power factor
(D) to provide additional mechanical strength.
78. In high voltage transmission lines the top most conductor is
(A) R-phase conductor
(B) Y- phase conductor
(C) B-phase conductor
(D) Earth conductor.
79. For 11 kV line the inductance per km per phase will be of the order of
(A) 1 H
(B) 0.1 H
(C) 1 mH
(D) 0.1 mH.
80. For 11 kV. line the capacitance per km per phase will be of the order of
(A) 1 Farad
(B) 0.1 Farad
(C) 0.01 Farad
(D) 0.01 microF.
81. 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) 66 kV
(D) 132 kV.
82. The permissible voltage variation in transmission and distribution system is
(A) 0.1%
(B) 1%
(C)10%
(D)25%.
83. The voltage of transmission can be regulated by
(A) use of tap changing transformers
(B) switching in shunt capacitors at the receiving end during heavy loads
(C) use of series capacitors to neutralize the effect of series reactance
(D) any of the above methods.
84. The most economic voltage for transmitting given power over a known distance by overhead transmission line is approximately
(A) 3.6 kV/km
(B) 1.6 kV/km
(C) 2.6 kV/km
(D) 3.6 kVkm.
85. String efficiency is given by
(A) (voltage across the string) / ((numbers of discs on the string) x (voltage across disc nearest to the conductor))
(B) ((voltage across the string) x (numbers of discs on the string)) / (voltage across disc nearest to the conductor)
(C) ( (voltage across disc nearest to the conductor) x (numbers of discs on the string)) / (voltage across the string)
(D) (voltage across disc nearest to the conductor))/ ((numbers of discs on the string) x (voltage across the string)
86. For a 66 kV line having span of 200 meters between towers the approximate sag will be
(A) 0.02 m
(B) 0.2 m
(C) 2 m
(D) 20 m.
87. In the above case if the span is doubled, the sag will be
(A) 2 m
(B) 4m
(C) 8m
(D) 1 m.
88. The reflection coefficient for a short circuit line is
(A) 1
(B) Zero
(C) 0.5
(D) - 1.
89. In case the height of transmission tower is increased
(A) the line capacitance and inductance will not change
(B) the line capacitance will decrease but line inductance will decrease
(C) the line capacitance will decrease and line inductance will increase
(D) the line capacitance will decrease but line inductance will remain unaltered.
90. In a transmission line if booster transformer are to be used, preferred location will be
(A) at the receiving end
(B) at the sending end
(C) at the intermediate point
(D) any where in the line.
(A) 0.50
(B) 0.75
(C) 1.50
(D) 2.0.
D
77. The function of steel wire in a ACSR conductor is
(A) to take care of surges
(B) to prevent corona
(C) to reduce inductance and hence improve power factor
(D) to provide additional mechanical strength.
D
78. In high voltage transmission lines the top most conductor is
(A) R-phase conductor
(B) Y- phase conductor
(C) B-phase conductor
(D) Earth conductor.
D
79. For 11 kV line the inductance per km per phase will be of the order of
(A) 1 H
(B) 0.1 H
(C) 1 mH
(D) 0.1 mH.
C
80. For 11 kV. line the capacitance per km per phase will be of the order of
(A) 1 Farad
(B) 0.1 Farad
(C) 0.01 Farad
(D) 0.01 microF.
C
81. 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) 66 kV
(D) 132 kV.
B
82. The permissible voltage variation in transmission and distribution system is
(A) 0.1%
(B) 1%
(C)10%
(D)25%.
C
83. The voltage of transmission can be regulated by
(A) use of tap changing transformers
(B) switching in shunt capacitors at the receiving end during heavy loads
(C) use of series capacitors to neutralize the effect of series reactance
(D) any of the above methods.
D
84. The most economic voltage for transmitting given power over a known distance by overhead transmission line is approximately
(A) 3.6 kV/km
(B) 1.6 kV/km
(C) 2.6 kV/km
(D) 3.6 kVkm.
A
85. String efficiency is given by
(A) (voltage across the string) / ((numbers of discs on the string) x (voltage across disc nearest to the conductor))
(B) ((voltage across the string) x (numbers of discs on the string)) / (voltage across disc nearest to the conductor)
(C) ( (voltage across disc nearest to the conductor) x (numbers of discs on the string)) / (voltage across the string)
(D) (voltage across disc nearest to the conductor))/ ((numbers of discs on the string) x (voltage across the string)
A
86. For a 66 kV line having span of 200 meters between towers the approximate sag will be
(A) 0.02 m
(B) 0.2 m
(C) 2 m
(D) 20 m.
C
87. In the above case if the span is doubled, the sag will be
(A) 2 m
(B) 4m
(C) 8m
(D) 1 m.
C
88. The reflection coefficient for a short circuit line is
(A) 1
(B) Zero
(C) 0.5
(D) - 1.
D
89. In case the height of transmission tower is increased
(A) the line capacitance and inductance will not change
(B) the line capacitance will decrease but line inductance will decrease
(C) the line capacitance will decrease and line inductance will increase
(D) the line capacitance will decrease but line inductance will remain unaltered.
D
90. In a transmission line if booster transformer are to be used, preferred location will be
(A) at the receiving end
(B) at the sending end
(C) at the intermediate point
(D) any where in the line.
C
91. A 70/6 ACSR conduction is an aluminium conductor steel reinforced, having
(A) cross sectional area of aluminium as 70 mm2 and the cross-sectional area of steel as 6 mm2
(B) cross-sectional area of steel as 70 mm2 and the cross-sections area of aluminium as 6 mm2
(C) 70 aluminium conductors and 6 steel conductors
(D) 80 steel conductors and 6 aluminium conductors.
92. In aluminium conductors steel reinforced, the insulation between aluminium and steel conductors is
(A) any insulator
(B) bitumen
(C) insulin
(D) no insulation is required.
93. Under no load conditions the current in a transmission line is due to
(A) corona effects
(B) capacitance of the line
(C) back flow from earth
(D) spinning reserve.
94. Which distribution system is more reliable ?
(A) Ring main system
(B) Tree system
(C) Radial system
(D) All are equally reliable.
95. Out of the following systems of distribution, which system offers the best economy ?
(A) Direct current system
(B) AC single phase system
(C) AC 3 phase 3 wire system
(D) AC 3 phase 4 wire system.
96. What are the advantages of dc transmission system over ac transmission system ?
(A) DC system is economical
(B) There is no skin effect in dc system
(C) Corona limits are highest for dc circuits as compared to ac circuits
(D) All of the above.
97. The main advantage of ac. transmission system over d.c. transmission system is
(A) Easy transformation
(B) Less losses in transmission over long distances
(C) ) Less insulation problems
(D) Less problem of instability.
98. Which curve correctly represents the relation between capital cost and dc voltage of transmission ?
(A) curve A
(B) curve B
(C) curve C
(D) curve D.
99. Step-up substations are associated with
(A) distributors
(B) consumer location
(C) concentrated load
(D) generating stations.
Questions 100 to 102 refer to figure given below :
100. A section of a single bus scheme is shown in the figure. In this figure B represents
(A) Isolator
(B) Circuit breaker
(C) Current transformer
(D) Inductance.
101. An isolator is represented by
(A) A
(B) B
(C) C
(D) A and D.
102. C represents
(A) circuit breaker
(B) Mho's relay
(C) Earth switch
(D) None of the above.
103. When an alternator is connected to the infinite but bar and its excitation is gradually increased
(A) the terminal voltage will rise
(B) the terminal voltage will drop
(C) the terminal voltage will remain unaltered
(D) the terminal voltage will vary rapidly.
104. Consumers having low power factor equipment are advised to install
(A) tap changing transformer
(B) capacitor bank
(C) synchronous condensers
(D) none of the above.
105. A bus bar is rated by
(A) current only
(B) current and voltage only
(C) current, voltage, frequency
(D) current, voltage, frequency and short time current.
(A) cross sectional area of aluminium as 70 mm2 and the cross-sectional area of steel as 6 mm2
(B) cross-sectional area of steel as 70 mm2 and the cross-sections area of aluminium as 6 mm2
(C) 70 aluminium conductors and 6 steel conductors
(D) 80 steel conductors and 6 aluminium conductors.
C
92. In aluminium conductors steel reinforced, the insulation between aluminium and steel conductors is
(A) any insulator
(B) bitumen
(C) insulin
(D) no insulation is required.
D
93. Under no load conditions the current in a transmission line is due to
(A) corona effects
(B) capacitance of the line
(C) back flow from earth
(D) spinning reserve.
B
94. Which distribution system is more reliable ?
(A) Ring main system
(B) Tree system
(C) Radial system
(D) All are equally reliable.
A
95. Out of the following systems of distribution, which system offers the best economy ?
(A) Direct current system
(B) AC single phase system
(C) AC 3 phase 3 wire system
(D) AC 3 phase 4 wire system.
A
96. What are the advantages of dc transmission system over ac transmission system ?
(A) DC system is economical
(B) There is no skin effect in dc system
(C) Corona limits are highest for dc circuits as compared to ac circuits
(D) All of the above.
D
97. The main advantage of ac. transmission system over d.c. transmission system is
(A) Easy transformation
(B) Less losses in transmission over long distances
(C) ) Less insulation problems
(D) Less problem of instability.
B
98. Which curve correctly represents the relation between capital cost and dc voltage of transmission ?
(A) curve A
(B) curve B
(C) curve C
(D) curve D.
B
99. Step-up substations are associated with
(A) distributors
(B) consumer location
(C) concentrated load
(D) generating stations.
D
Questions 100 to 102 refer to figure given below :
100. A section of a single bus scheme is shown in the figure. In this figure B represents
(A) Isolator
(B) Circuit breaker
(C) Current transformer
(D) Inductance.
C
101. An isolator is represented by
(A) A
(B) B
(C) C
(D) A and D.
D
102. C represents
(A) circuit breaker
(B) Mho's relay
(C) Earth switch
(D) None of the above.
A
103. When an alternator is connected to the infinite but bar and its excitation is gradually increased
(A) the terminal voltage will rise
(B) the terminal voltage will drop
(C) the terminal voltage will remain unaltered
(D) the terminal voltage will vary rapidly.
C
104. Consumers having low power factor equipment are advised to install
(A) tap changing transformer
(B) capacitor bank
(C) synchronous condensers
(D) none of the above.
B
105. A bus bar is rated by
(A) current only
(B) current and voltage only
(C) current, voltage, frequency
(D) current, voltage, frequency and short time current.
D
106. Material generally used for bus bar is
(A) copper
(B) aluminium
(C) steel
(D) tungsten.
107. Which of following properties has got higher value for aluminium as compared to copper?
(A) Melting point
(B) Specific gravity
(C) Electrical resistivity
(D) Thermal conductivity.
108. For carrying a 100 A (rms) current the cross-sectional area of aluminium bus bar should be at least
(A) 1 mm2
(B) 10 mm 2
(C) 25 mm 2
(D) 50 mm2
109. Isolators are used to disconnect a circuit when
(A) line is on full load
(B) line is energized
(C) circuit breaker is not open
(D) there is no current in the line.
110. Tap changing transformers are used for
(A) stepping up the voltage
(B) stepping down the voltage
(C) both stepping up and stepping down the voltage
(D) supplying low voltage current for instruments.
111. Which device automatically interrupts the supply in the event of surges
(A) Earthing switch
(B) Series reactor
(C) Isolator
(D) Circuit breaker.
112. In a substation the equipment used to limit short circuit current level is
(A) Series reactor
(B) Coupling capacitor
(C) Lightening switch
(D) Isolator.
113. Which of the following equipment is not installed in a substation ?
(A) Shunt reactors
(B) Exciters
(C) Voltage transformers
(D) Series capacitors.
114. Which bus bar scheme offers the lowest cost ?
(A) Single bus bar scheme
(B) Ring bus bar scheme
(C) Breaker and a half scheme
(D) Main and transfer scheme.
115. Which is the most expensive bus bar scheme ?
(A) Single bus bar scheme
(B) Ring bus bar scheme
(C) Double bus bar double breaker
(D) Main and transfer scheme.
116. Current rating is not necessary in case of
(A) Isolators
(B) Circuit breakers
(C) Load break switches
(D) Circuit breakers and load break switches.
117. 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 isolator - close circuit breaker - open earthing switch
(C) Open circuit breaker - open isolator - close earthing switch
(D) Close circuit breaker - close isolator - open earthing switch.
118. 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 closed - close isolator - open earthing switch
(B) Ensure circuit breaker is open - close isolator - open earthing switch if any close circuit breaker
(C) Ensure circuit breaker is open - open isolator - open earthing switch if any - close circuit breaker.
(D) None of the above.
119. Which of the following type tests are conducted on isolators
(A) Temperature rise test
(B) Impulse stage with stand test
(C) Short time current test
(D) All of the above.
120. In a balance 3 f , 4 wire AC system, the phase sequence is RYB. If the voltage of R phase is. 230 < 0 V, then for Y phase
(A) 230 < 0 V
(B) 230 < 60 V
(C) 230 < 90°V
(D) 230 < 120 V.
(A) copper
(B) aluminium
(C) steel
(D) tungsten.
B
107. Which of following properties has got higher value for aluminium as compared to copper?
(A) Melting point
(B) Specific gravity
(C) Electrical resistivity
(D) Thermal conductivity.
C
108. For carrying a 100 A (rms) current the cross-sectional area of aluminium bus bar should be at least
(A) 1 mm2
(B) 10 mm 2
(C) 25 mm 2
(D) 50 mm2
C
109. Isolators are used to disconnect a circuit when
(A) line is on full load
(B) line is energized
(C) circuit breaker is not open
(D) there is no current in the line.
D
110. Tap changing transformers are used for
(A) stepping up the voltage
(B) stepping down the voltage
(C) both stepping up and stepping down the voltage
(D) supplying low voltage current for instruments.
C
111. Which device automatically interrupts the supply in the event of surges
(A) Earthing switch
(B) Series reactor
(C) Isolator
(D) Circuit breaker.
D
112. In a substation the equipment used to limit short circuit current level is
(A) Series reactor
(B) Coupling capacitor
(C) Lightening switch
(D) Isolator.
A
113. Which of the following equipment is not installed in a substation ?
(A) Shunt reactors
(B) Exciters
(C) Voltage transformers
(D) Series capacitors.
B
114. Which bus bar scheme offers the lowest cost ?
(A) Single bus bar scheme
(B) Ring bus bar scheme
(C) Breaker and a half scheme
(D) Main and transfer scheme.
A
115. Which is the most expensive bus bar scheme ?
(A) Single bus bar scheme
(B) Ring bus bar scheme
(C) Double bus bar double breaker
(D) Main and transfer scheme.
C
116. Current rating is not necessary in case of
(A) Isolators
(B) Circuit breakers
(C) Load break switches
(D) Circuit breakers and load break switches.
A
117. 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 isolator - close circuit breaker - open earthing switch
(C) Open circuit breaker - open isolator - close earthing switch
(D) Close circuit breaker - close isolator - open earthing switch.
C
118. 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 closed - close isolator - open earthing switch
(B) Ensure circuit breaker is open - close isolator - open earthing switch if any close circuit breaker
(C) Ensure circuit breaker is open - open isolator - open earthing switch if any - close circuit breaker.
(D) None of the above.
B
119. Which of the following type tests are conducted on isolators
(A) Temperature rise test
(B) Impulse stage with stand test
(C) Short time current test
(D) All of the above.
D
120. In a balance 3 f , 4 wire AC system, the phase sequence is RYB. If the voltage of R phase is. 230 < 0 V, then for Y phase
(A) 230 < 0 V
(B) 230 < 60 V
(C) 230 < 90°V
(D) 230 < 120 V.
D
121. The relation between traveling voltage wave and current wave is
(A) e = i (L/C) 1/2
(B) e = i (C/L) 1/2
(C) e = i (iL/C) 1/2
(D) (L/iC) 1/2
122. Steepness of the traveling waves is attenuated by
(A) resistance of the line
(B) inductance of the line
(C) capacitance of the line
(D) all of the above.
123. The protection against direct lightening strokes and high voltage steep waves is provided by
(A) earthing of neutral
(B) lightening arresters
(C) ground wires
(D) lightening arresters and ground wires.
124. Voltages under Extra High Voltage are
(A) 1 kV and above
(B) 11 kV and above
(C) 132 kV and above
(D) 330 kV and above.
125. In outdoor substation, the lightening arresters is placed nearer to
(A) the isolator
(B) the current transformer
(C) the power transformer
(D) the current breaker.
126. Stability of a system is not affected by
(A) Reactance of line
(B) Losses
(C) Reactance of generator
(D) Output torque.
127. A 10 MVA generator has power factor 0.866 lagging. The reactive power produced will be
(A) 10 MVA
(B) 8 MVA
(C) 5 MVA
(D) 1.34 MVA.
128. In order to increase the limit of distance of transmission line
(A) series resistances are used
(B) synchronous condensers are used
(C) shunt capacitors and series reactors are used
(D) series capacitors and shunt reactors are used.
129. A 30 km transmission line carrying power at 33 kV is known as
(A) short transmission line
(B) long transmission line
(C) high power line
(D) ultra high voltage line.
130. If K is the volume of conductor material required for 2 wire dc system with one conductor earthed, then the volume of cable conductor material required for transmission of same power in single phase 3 wire system is (A) K/3 cos f
(B) 5K cos2f
(C) K/ 5 cos2f
(D) 5K/ 8 cos2f
131. The permissible voltage variable in voltage in distribution is
(A) 0.1%
(B) 1%
(C) 10%
(D) 50%.
132. Surge impedance of transmission line is given by
(A) (L/C)1/2
(B) (C/L)1/2
(C) (CL)1/2
(D) 1/(CL)1/2
133. 750 kV is termed as
(A) Medium high voltage
(B) High voltage
(C) Extra high voltage
(D) Ultra high voltage.
134. In case of transmission line conductors with the increase in atmospheric temperature
(A) length increase but stress decreases
(B) length increases and stress also increases
(C) length decreases but stress increases
(D) both length as well as stress decreases.
135. If the height of transmission towers is increased, which of the following parameters is likely to change ?
(A) Resistance
(B) Inductance
(C) Capacitance
(D) None of the above.
(A) e = i (L/C) 1/2
(B) e = i (C/L) 1/2
(C) e = i (iL/C) 1/2
(D) (L/iC) 1/2
A
122. Steepness of the traveling waves is attenuated by
(A) resistance of the line
(B) inductance of the line
(C) capacitance of the line
(D) all of the above.
A
123. The protection against direct lightening strokes and high voltage steep waves is provided by
(A) earthing of neutral
(B) lightening arresters
(C) ground wires
(D) lightening arresters and ground wires.
D
124. Voltages under Extra High Voltage are
(A) 1 kV and above
(B) 11 kV and above
(C) 132 kV and above
(D) 330 kV and above.
D
125. In outdoor substation, the lightening arresters is placed nearer to
(A) the isolator
(B) the current transformer
(C) the power transformer
(D) the current breaker.
C
126. Stability of a system is not affected by
(A) Reactance of line
(B) Losses
(C) Reactance of generator
(D) Output torque.
B
127. A 10 MVA generator has power factor 0.866 lagging. The reactive power produced will be
(A) 10 MVA
(B) 8 MVA
(C) 5 MVA
(D) 1.34 MVA.
C
128. In order to increase the limit of distance of transmission line
(A) series resistances are used
(B) synchronous condensers are used
(C) shunt capacitors and series reactors are used
(D) series capacitors and shunt reactors are used.
D
129. A 30 km transmission line carrying power at 33 kV is known as
(A) short transmission line
(B) long transmission line
(C) high power line
(D) ultra high voltage line.
A
130. If K is the volume of conductor material required for 2 wire dc system with one conductor earthed, then the volume of cable conductor material required for transmission of same power in single phase 3 wire system is (A) K/3 cos f
(B) 5K cos2f
(C) K/ 5 cos2f
(D) 5K/ 8 cos2f
C
131. The permissible voltage variable in voltage in distribution is
(A) 0.1%
(B) 1%
(C) 10%
(D) 50%.
C
132. Surge impedance of transmission line is given by
(A) (L/C)1/2
(B) (C/L)1/2
(C) (CL)1/2
(D) 1/(CL)1/2
A
133. 750 kV is termed as
(A) Medium high voltage
(B) High voltage
(C) Extra high voltage
(D) Ultra high voltage.
D
134. In case of transmission line conductors with the increase in atmospheric temperature
(A) length increase but stress decreases
(B) length increases and stress also increases
(C) length decreases but stress increases
(D) both length as well as stress decreases.
A
135. If the height of transmission towers is increased, which of the following parameters is likely to change ?
(A) Resistance
(B) Inductance
(C) Capacitance
(D) None of the above.
C
136. For increasing the capacity of a transmission line to transmit power which of the following must be decreased ?
(A) Voltage
(B) Capacitance
(C) Line inductance
(D) All of the above.
137. In terms of constants A, B, C and D for short transmission lines, which of the following relation is valid ?
(A) A = B = 1
(B) B = D = 0
(C) A = C = 1
(D) C=0.
138.Which of the following is reduced due to the use of bundled conductors ?
(A) Capacitance of the circuit
(B) lnductance of the circuit
(C) Power loss due to corona
(D) All of the above.
139. The ratio of capacitance from line to line capacitance from line to neutral is nearly
(A)1/4
(B) 1/2
(C) 1
(D) 2.
140. Following effects are associated with transmission lines
I. Corona effect
II. Proximity effect
III. Skin effect.
The effect resistance of a conductor is increased by
(A) I only
(B) II and III only
(C) I and III only
(D) I. II and III.
141. The sag of a transmission line is least affected by
(A) self weight of conductors
(B) temperature of surrounding air
(C) current through conductor
(D) ice deposited on conductor.
142. The sag of the conductors of a transmission line is 1.5 m when the span is 100 m. Now if the height of supporting towers is increased by 20%, the sag will
(A) increase by 20%
(B) increase by 10%
(C) reduced by 20%
(D) remain unchanged.
143. ACSR conductor having 7 steel stands surrounded by 25 aluminum conductor will be specified as
(A) 7/25
(B) 7/32
(C) 25/7
(D) 25/32.
144. The networks associated with transmission lines are
I. T-network
II. π network
III. Tree net.
A two terminal pair of network of a transmission line can be represented by
(A) I only
(B) II only
(C) Either of I or II
(D) Either of I, II or III.
145. Which of the following relationships is not valid for short transmission lines ?
(A) B = Z = C
(B) A = D = 1
(C) Is = Ir
(D) None of the above.
146. In order to improve the steady state stability of an overhead transmission lines, which of the following methods can be adopted
(A) Reducing impedance between the stations
(B) Adopting quick response excitation systems
(C) Using series capacitors to make X = (3 R)1/2
(D) Any of the above.
147. Transient disturbances arc due to
(A) Switching operations
(B) Load variations
(C) Faults
(D) Any of the above.
148. Which of the following short circuit is the most dangerous ?
(A) Line to line short circuit
(B) Dead short circuit
(C) Line to ground short circuit
(D) Line to line and ground short circuit.
149. In case line to line fault occurs, the short circuit current of an alternator will .depend on its
(A) Synchronous reactance
(B) Transient reactance
(C) Short circuit resistance
(D) All of the above.
150. Transient state stability is generally improved by ,
(A) using high speed governors on machines by
(B) using low inertia machines
(C) dispensing with neutral grounding
(D) any of the above.
(A) Voltage
(B) Capacitance
(C) Line inductance
(D) All of the above.
C
137. In terms of constants A, B, C and D for short transmission lines, which of the following relation is valid ?
(A) A = B = 1
(B) B = D = 0
(C) A = C = 1
(D) C=0.
D
138.Which of the following is reduced due to the use of bundled conductors ?
(A) Capacitance of the circuit
(B) lnductance of the circuit
(C) Power loss due to corona
(D) All of the above.
C
139. The ratio of capacitance from line to line capacitance from line to neutral is nearly
(A)1/4
(B) 1/2
(C) 1
(D) 2.
A
140. Following effects are associated with transmission lines
I. Corona effect
II. Proximity effect
III. Skin effect.
The effect resistance of a conductor is increased by
(A) I only
(B) II and III only
(C) I and III only
(D) I. II and III.
B
141. The sag of a transmission line is least affected by
(A) self weight of conductors
(B) temperature of surrounding air
(C) current through conductor
(D) ice deposited on conductor.
C
142. The sag of the conductors of a transmission line is 1.5 m when the span is 100 m. Now if the height of supporting towers is increased by 20%, the sag will
(A) increase by 20%
(B) increase by 10%
(C) reduced by 20%
(D) remain unchanged.
D
143. ACSR conductor having 7 steel stands surrounded by 25 aluminum conductor will be specified as
(A) 7/25
(B) 7/32
(C) 25/7
(D) 25/32.
C
144. The networks associated with transmission lines are
I. T-network
II. π network
III. Tree net.
A two terminal pair of network of a transmission line can be represented by
(A) I only
(B) II only
(C) Either of I or II
(D) Either of I, II or III.
C
145. Which of the following relationships is not valid for short transmission lines ?
(A) B = Z = C
(B) A = D = 1
(C) Is = Ir
(D) None of the above.
A
146. In order to improve the steady state stability of an overhead transmission lines, which of the following methods can be adopted
(A) Reducing impedance between the stations
(B) Adopting quick response excitation systems
(C) Using series capacitors to make X = (3 R)1/2
(D) Any of the above.
D
147. Transient disturbances arc due to
(A) Switching operations
(B) Load variations
(C) Faults
(D) Any of the above.
D
148. Which of the following short circuit is the most dangerous ?
(A) Line to line short circuit
(B) Dead short circuit
(C) Line to ground short circuit
(D) Line to line and ground short circuit.
B
149. In case line to line fault occurs, the short circuit current of an alternator will .depend on its
(A) Synchronous reactance
(B) Transient reactance
(C) Short circuit resistance
(D) All of the above.
A
150. Transient state stability is generally improved by ,
(A) using high speed governors on machines by
(B) using low inertia machines
(C) dispensing with neutral grounding
(D) any of the above.
A
151. Aluminium is being favored as bus-bar material mainly because of
(A) case of fabrication
(B) low density
(C) low cost
(D) non availability of copper.
152. Which section can lie used for bus bar ?
(A) bars
(B) rods
(C) tubes
(D) any of the above.
153. A string efficiency of 100% implies that
(A) shunt capacitance is 1 MF
(B) potential across each disc is same
(C) potential across each disc is zero
(D) one of the insulator disc is shorted.
154. Steel poles for transmission lines need protection against
(A) termites
(B) borer
(C) corrosion
(D) all of the above.
155. Which type of copper wire will have highest tensile strength ?
(A) Soft drawn
(B) Medium drawn
(C) Hard drawn.
156. 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.
157. Which of the following is a leading power system ?
(A) Underground cables
(B) Reactors
(C) Mercury arc rectifiers
(D)Transformers.
158. Which of the following is a static exciter ?
(A) dc separately excited generator
(B) amplidyne
(C) retool
(D) rectifier.
159. The service mains connect
(A) distributor and consumer terminals
(B) distributor and transformer
(C) distributor and relay system
(D) transformer and earth.
160. System grounding is song
(A) so that the floating potential on the lower voltage winding for a transformer is brought down to an insignificant value
(B) so that arcing faults to earth would not set up dangerously high voltage on healthy phases
(C) so that inductive interference between power and communication circuits can be controlled
(D) for all above reasons.
161. Hot template curves are plots of
(A) conductor sage and span lengths
(B) temperature and ground clearance curves
(C) temperature and humidity
(D) conductor weight and sag.
Questions 162 and 163 refer to data given below:
A 66 kV system has string insulator having five discs and the earth to disc capacitance ratio of 0.10.
162. The string efficiency will be
(A) 89%
(B) 75%
(C) 67%
(D) 55%.
163. The voltage shared by the individual discs will be
(A) 1.25 kV
(B) 2.50 kV
(C) 3.88 kV
(D) 5.28 kV.
164. The shape of heat rate (HR) versus power (P) curve for a power station will be as shown in
(A) figure A
(B) figure B
(C) figure C
(D) figure D
165. The reflection coefficient for the voltage wave in case of overhead lines is given by
(A) (RL - R0 )/ (RL+ R0)
(B) (RL + R0 )/ (RL- R0)
(C) (RL + R0 )/ (RL+ R0)
(D) (RL R0 )/ (RL- R0)
166. In a diesel engine the governor controls
(A) fuel pressure
(B) fuel flow rate
(C) fuel temperature
(D) fuel volume.
167. For overhead transmission line when the conductors are supported between two supports, the variation of tension T will temperature is represented by
(A) Curve A
(B) Curve B
(C) Curve C
(D) Curve D.
168. If the voltage across the units in a two unit suspension insulator is 60% and 40% respectively of the line voltage, the. ratio of capacitance of the insulator to that of its capacitance to earth will be
(A) 0.5
(B) 0.50
(C) 0.65
(D) 0.75.
169. In the analysis of short transmission lines which of the following is neglected ?
(A) I2 R loss
(B) Shunt admittance
(C) Series impedance
(D) All of the above.
170. In medium transmission lines the shunt capacitance is taken into account in
(A) Tee method
(B) Pie method
(C) Steinmetz method
(D) all of the above.
Questions 171 and 172 refer to data given below:
A transmission line has a capacitance of 0.01 micro F/km and an inductance of 2 mH/km and is connected to a cable having an inductance of 0.25 mH/km. When voltage surge having peak value of 100 kV travels along the cable towards the line, the resulting peak voltage at the junction of the cable and the line is 180 kV.
171. The surge impedance of the cable is
(A) 14.1 ohms
(B) 42.5 ohms
(C) 87.75 ohms
(D) 141.2 ohms.
172 . The capacitance of cable per km is
(A) 0.1 microF
(B) 0.7 microF
(C) 1.5 microF
(D) 10 microF.
(A) case of fabrication
(B) low density
(C) low cost
(D) non availability of copper.
C
152. Which section can lie used for bus bar ?
(A) bars
(B) rods
(C) tubes
(D) any of the above.
D
153. A string efficiency of 100% implies that
(A) shunt capacitance is 1 MF
(B) potential across each disc is same
(C) potential across each disc is zero
(D) one of the insulator disc is shorted.
B
154. Steel poles for transmission lines need protection against
(A) termites
(B) borer
(C) corrosion
(D) all of the above.
C
155. Which type of copper wire will have highest tensile strength ?
(A) Soft drawn
(B) Medium drawn
(C) Hard drawn.
C
156. 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.
A
157. Which of the following is a leading power system ?
(A) Underground cables
(B) Reactors
(C) Mercury arc rectifiers
(D)Transformers.
A
158. Which of the following is a static exciter ?
(A) dc separately excited generator
(B) amplidyne
(C) retool
(D) rectifier.
D
159. The service mains connect
(A) distributor and consumer terminals
(B) distributor and transformer
(C) distributor and relay system
(D) transformer and earth.
A
160. System grounding is song
(A) so that the floating potential on the lower voltage winding for a transformer is brought down to an insignificant value
(B) so that arcing faults to earth would not set up dangerously high voltage on healthy phases
(C) so that inductive interference between power and communication circuits can be controlled
(D) for all above reasons.
D
161. Hot template curves are plots of
(A) conductor sage and span lengths
(B) temperature and ground clearance curves
(C) temperature and humidity
(D) conductor weight and sag.
A
Questions 162 and 163 refer to data given below:
A 66 kV system has string insulator having five discs and the earth to disc capacitance ratio of 0.10.
162. The string efficiency will be
(A) 89%
(B) 75%
(C) 67%
(D) 55%.
C
163. The voltage shared by the individual discs will be
(A) 1.25 kV
(B) 2.50 kV
(C) 3.88 kV
(D) 5.28 kV.
D
164. The shape of heat rate (HR) versus power (P) curve for a power station will be as shown in
(A) figure A
(B) figure B
(C) figure C
(D) figure D
C
165. The reflection coefficient for the voltage wave in case of overhead lines is given by
(A) (RL - R0 )/ (RL+ R0)
(B) (RL + R0 )/ (RL- R0)
(C) (RL + R0 )/ (RL+ R0)
(D) (RL R0 )/ (RL- R0)
A
166. In a diesel engine the governor controls
(A) fuel pressure
(B) fuel flow rate
(C) fuel temperature
(D) fuel volume.
B
167. For overhead transmission line when the conductors are supported between two supports, the variation of tension T will temperature is represented by
(A) Curve A
(B) Curve B
(C) Curve C
(D) Curve D.
C
168. If the voltage across the units in a two unit suspension insulator is 60% and 40% respectively of the line voltage, the. ratio of capacitance of the insulator to that of its capacitance to earth will be
(A) 0.5
(B) 0.50
(C) 0.65
(D) 0.75.
B
169. In the analysis of short transmission lines which of the following is neglected ?
(A) I2 R loss
(B) Shunt admittance
(C) Series impedance
(D) All of the above.
B
170. In medium transmission lines the shunt capacitance is taken into account in
(A) Tee method
(B) Pie method
(C) Steinmetz method
(D) all of the above.
D
Questions 171 and 172 refer to data given below:
A transmission line has a capacitance of 0.01 micro F/km and an inductance of 2 mH/km and is connected to a cable having an inductance of 0.25 mH/km. When voltage surge having peak value of 100 kV travels along the cable towards the line, the resulting peak voltage at the junction of the cable and the line is 180 kV.
171. The surge impedance of the cable is
(A) 14.1 ohms
(B) 42.5 ohms
(C) 87.75 ohms
(D) 141.2 ohms.
D
172 . The capacitance of cable per km is
(A) 0.1 microF
(B) 0.7 microF
(C) 1.5 microF
(D) 10 microF.
A
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