MCQ on Power System

1.For aluminum, as compared to copper, all the following factors have higher values except

(a) specific volume
(b) electrical conductivity
(c) co-efficient of linear expansion
(d) resistance per unit length for same cress-section


Answer: (b) electrical conductivity
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2.Which of the following equipment, for regulating the voltage in distribution feeder, will be most economical ?

(a) Static condenser
(b) Synchronous condenser
(c) Tap changing transformer
(d) Booster transformer


Answer: (d) Booster transformer
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3.In a tap changing transformer, the tappings are provided on

(a) primary winding
(b) secondary winding
(c) high voltage winding
(d) any of the above


Answer: (b) secondary winding
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4.Constant voltage transmission has the following disadvantage

(a) small conductor area is required for same power transmission
(b) short-circuit current of the system is increased
(c) either of the above
(d) none of the above


Answer: (b) short-circuit current of the system is increased
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5. On which of the following factors skin effect depends ?

(a) Frequency of the current
(b) Size of the conductor
(c) Resistivity of the conductor material
(d) All of the above


Answer: (d) All of the above
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6.The effect of corona can be detected by

(a) presence of ozone detected by odor
(b) hissing sound
(c) faint luminous glow of bluish color
(d) all of the above.


Answer: (d) all of the above.
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7.For transmission of power over a distance of 600 km, the transmission voltage should be in the range

(a) 150 to 220 kV
(b) 100 to 120 kV
(c) 60 to 100 kV
(d) 20 to 50 kV.


Answer: (a) 150 to 220 kV
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8.In the analysis of which of the following lines shunt capacitance is neglected ?

(a) Short transmission lines
(b) Medium transmission lines
(d) Long transmission lines
(d) Medium as well as long transmission lines.


Answer: (a) Short transmission lines
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9.When the interconnector between two stations bas large reactance

(a) the transfer of power will take place with voltage fluctuation and noise
(b) the transfer of power will take place with least loss
(c) the stations will fall out of step because of large angular displacement between the stations
(d) none of the above.


Answer: (c) the stations will fall out of step because of large angular displacement between the stations
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10.The frequency of voltage generated in case of generators, can be increased by

(a) using reactors
(b) increasing the load
(c) adjusting the governor
(d) reducing the terminal voltage


Answer: (c) adjusting the governor
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11.When an alternator connected to the bus-bar is, shut down the bus-bar voltage will

(a) fall
(b) rise
(c) remain unchanged
(d) none of the above.


Answer: (c) remain unchanged
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12.The angular displacement between two interconnected stations is mainly due to

(a) armature reactance of both alternators
(b) reactance of the interconnector
(c) synchronous reactance of both the alternators
(d) all of the above.


Answer: (b) reactance of the interconnector
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13.Electro-mechanical voltage regulators are generally used in

(a) reactors
(b) generators
(c) transformers
(d) all of the above.


Answer: (b) generators
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14.Series capacitors on transmission lines are of little use when the load VAR requirement is

(a) large
(b) small
(c) fluctuating
(d) any of the above.


Answer: (b) small
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15.The voltage regulation in magnetic amplifier type voltage regulator is effected by

(a) electromagnetic induction
(b) varying the resistance
(c) varying the reactance
(d) variable transformer.


Answer: (c) varying the reactance
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16.When a conductor carries more current on the surface as compared to core, it is due to

(a) permeability variation
(b) corona
(c) skin effect
(d) unsymmetrical fault.


Answer: (c) skin effect
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17.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: (b) 1-phase 4 wire
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18.The skin effect of a conductor will reduce as the

(a) resistivity of conductor material increases
(b) permeability of conductor material increases
(c) diameter increases
(d) frequency increases.


Answer: (a) resistivity of conductor material increases
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19.When a live conductor of public electric supply breaks down and touches the earth which of the following will happen ?

(a) Current will flow to earth
(b) Supply voltage will drop
(c) Supply voltage will increase
(d) No current will flow in the conductor.


Answer: (a) Current will flow to earth
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20.A 310 km line is considered as

(a) a long line
(b) a medium line
(c) a short line
(d) any of the above.


Answer: (a) a long line
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21.The conductors are bundled primarily to

(a) increase reactance
(b) reduce reactance
(c) reduce radio interference
(d) none of the above.


Answer: (b) reduce reactance
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22.The top most conductor in a high transmission line is

(a) earth conductor
(b) R-phase conductor
(c) Y-phase conductor
(d) B-phase conductor


Answer: (a) earth conductor
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23.By which of the following methods voltage of transmission can be regulated ?

(a) Use of series capacitors to neutralize the effect of series reactance
(b) Switching in shunt capacitor at the receiving end during heavy loads
(c) Use of tap changing transformers
(d) Any of the above methods.


Answer: (d) Any of the above methods.
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24.Which of the following distribution systems is the most economical ?

(a) A.C. 1-phase system
(b) A.C. 3-phase 3 wire system
(c) A.C. 3-phase 4 wire system
(d) Direct current system.


Answer: (d) Direct current system.
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25.Which of the following is the main advantage of AC transmission system over DC transmission system?

(a) Less instability problem
(b) Less insulation problems
(c) Easy transformation
(d) Less losses in transmission over long distances.


Answer: (d) Less losses in transmission over long distances.
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26.A tap changing transformer is used to

(a) supply low voltage current for instruments
(b) step up the voltage
(c) step down the voltage
(d) step up as well as step down the voltage.


Answer: (d) step up as well as step down the voltage.
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27.Which of the following bus-bar schemes is the most expensive ?

(a) Double bus-bar double breaker
(b) Ring bus-bar scheme
(c) Single bus-bar scheme
(d) Main and transfer scheme


Answer: (a) Double bus-bar double breaker
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28.By which of the following methods the protection against direct lightning strokes and high voltage sweep waves is provided ?

(a) Lightening arresters
(b) Ground wire
(c) Lightening arresters and ground wires
(d) Earthing of neutral.


Answer: (c) Lightening arresters and ground wires
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29.In which of the following voltage regulators the effect of dead zero is found ?

(a) Electromagnetic type
(b) Magnetic amplifier
(c) Electronic type using integrated circuits
(d) All of the above.


Answer: (a) Electromagnetic type
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30.Corona results in

(a) radio interference
(b) power factor improvement
(c) better regulation
(d) none of the above.


Answer: (a) radio interference
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MCQ on Power System

 

  1. Power System MCQ With Answers
  2. Power System Multiple Choice Questions
  3. MCQ on Power System
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