Transmission and Distribution MCQ PDF

61. Capacitors are used in power system to

(a) improve supply power factor.
(b) improve voltage regulation.
(c) change the load characteristics.
(d) all of the above.

62. Series capacitors on transmission lines are of little use when

(a) the load VAR requirement is small.
(b) the load VAR requirement is large.
(c) the load VAR requirement is fluctuating.
(d) series capacitors are never used in transmission lines.

63. The reactive power transfer over a line mainly depends on

(a) power angle δ.
(b) |V_s| – |V_R|
(c) V_s.
(d) V_R.

64. For a fixed value of complex power flow in a transmission line having a sending end voltage V, the real power loss will be proportional to

(a)V
(b)V²
(c)1/V²
(d)1/V

64. For a fixed receiving-end and sending-end voltages in a transmission system, what is the locus of the constant power?

(a) A straight line.
(b) An ellipse.
(c) A parabola.
(d) A circle. [I.E.S. E.E.-II, 2004]

65. Conduit pipe is generally employed for protection of

(a) unsheathed cables.
(b) armoured cables.
(c) PVC sheathed cables.
(d) all of above.

66. Sheaths are used in cables to

(a) provide proper insulation.
(b) provide mechanical strength.
(c) prevent ingress of moisture.
(d) none of the above.

67. The bedding on a cable consists of

(a) jute strands.
(d) hessian tape.
(c) paper tape compounded with a fibrous material.
(d) any of the above.

68. The material(s) used for armouring of an underground cable is/are

(a) galvanized steel wire.
(b) steel tape.
(c) aluminum.
(d) either (a) or (b).

69. Metallic shielding is provided on underground cables to

(a) reduce thermal resistance.
(b) reduce corona effect.
(c) control the electrostatic voltage stress.
(d) all of the above.

70. Metallic shielding provided on cables is usually of thickness.

(a) 0.1 – 0.8 mm.
(b) 3 – 5 mm.
(c) 10 – 15 mm.
(c) 15 – 25 mm.

71. The effect of bonding the cable is

(a) to increase the effective resistance and inductance.
(b) to increase the effective resistance but reduce inductance.
(c) to reduce the effective resistance and inductance.
(d) to reduce the effective resistance but increase the inductance

72. The thickness of insulation layer provided on the conductor, in cables, depends upon

(a) operating voltage.
(b) current to be carried.
(c) power factor.
(d) both (a) and (b).

73. The insulating material used for cables should have all of the following except

(a) high dielectric strength, high mechanical strength, high tensile strength and plasticity, high resistivity and high viscosity at impregnation temperature.
(b) low thermal coefficient, low permittivity, acid proof, non-inflammable and non-hygroscopic.
(c) high water absorption.
(d) capability of withstanding high rupturing voltages.

74. Empire tape is

(a) varnished cambric.
(b) impregnated paper.
(c) vulcanized rubber.
(d) enamel insulation.

75. Paper as an insulating material has the main drawback that it

(a) is hygroscopic.
(b) has poor dielectric strength.
(c) has low insulation resistivity.
(d) has high capacitance.

76. In paper insulated cables, the conductor x-section is usually limited to

(a) 50 mm²
(b) 250 mm²
(c) 600 mm²
(d) 1200 mm²

77. The dielectric strength of impregnated paper is about

(a) 30 kV/mm
(b) 20kV/mm
(c) 15 kV/mm
(d) 5 kV/mm

78. Paper used as an insulating material is usually treated with oily compound because it

(a) is hygroscopic.
(b) gets electrostatically charged at high voltage.
(c) is porous.
(d) all of the above.

79. Single-core cables are usually not provided with armouring in order to

(a) avoid excessive loss in the armour.
(b) make the cable more flexible.
(c) make the cable non-hygroscopic.
(d) none of the above.

80. Single-core cable should have armour made of

(a) magnetic material.
(b) non-magnetic and non-conducting material.
(c) non-magnetic but conducting material.