MCQ
61. Suspension insulators are used when transmission voltage is-
high
low
fluctuating
steady
62. Interference between a power line and a communication line is due to-
electromagnetic induction
electrostatic induction
electromagnetic and electrostatic induction.
none of the above
63. The skin effect shows that-
the distribution of AC current is uniform through the cross section of the conductor
current density is more at the centre of the condutor
current density is lower at the surface of the condutor
current density is more at the surface of the condutor
64. Common declared distribution voltage in Bangladesh for low voltage circuit is-
230 Volts
250 Volts
440 Volts
380 Volts
65. If the fault current is 2000A, the relay setting is 50% and CT ratio is 400: 5, then plug setting multiplier will be-
10
25
15
50
66. When power is to be transmitted over a distance of 250km, the transmission voltage should be-
66kV
132kV
33kV
11kV
67. Plog setting of a relay can be altered by varying-
air gap of magnetic path
adjustable back up stop
no. of ampere-turns
none of these
68. Routing means connecting-
Circuit or equipment to earth
Impent to earth
Circuit to earth
None of the above
69. Permissible variation in power frequency in Bangladesh is-
±0.1%
±1%
±5%
±10%
70. Objectives of power system is/are-
Cost of electrical energy per kWh is to be minimum
Rated voltage and frequency has to be supplied to the consumers
both 1 and 2
nether 1 nor 2
71. The volume of copper required for an ac transmission line is inversely proportional to-
current
voltage
power factor
both b & c
72. India's largest thermal power station is located at--
Madhya Pradesh
Neyveli
Kota
Chandrapur
73. Length of the cable is doubled, its capacitance C will be-
one-fourth
doubled
one-half
unchanged
74. Which of the following rotor is used in thermal power plants?
cylindrical rotor
salient pole rotor
squirrel cage rotor
either of these
75. Find the number of strands of ACSR conductor for 4 layer transmission line.
1
67
37
2
76. Which distribution system is more reliable?
Ring main system
Tree system
Radial System
All are equally reliable
77. Which is used for power factor improvement?
Spring motor
Sychronous motor
Commutator motor
Squirrel case motor
78. Proximity effect is more in case of-
power cables
same in both cases
overhead lines
none of the above
79. If the frequency is increased, then skin effect will—
increases
decreases
remains unaffected
any of the above
80. Four identical alternators each are rated for 20 MVA, 11KV having a subtransient reactance of 16% are working in parallel. The short circuit level at the busbar is-
500 MVA
400 MVA
125 MVA
100 MVA