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100+ Transmission and Distribution of Electrical Energy Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Electrical Engineering .

1.

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

A. Overhead system
B. Underground system
C. Both (a) and (b)
D. None of the above
Answer» C. Both (a) and (b)
2.

are the conductors, which connect the consumer’s terminals to the distribution

A. Distributors
B. Service mains
C. Feeders
D. None of the above
Answer» B. Service mains
3.

The underground system cannot be operated above

A. 440 V
B. 11 kV
C. 33 kV
D. 66 kV
Answer» D. 66 kV
4.

Overhead system can be designed for operation up to

A. 11 kV
B. 33 kV
C. 66 kV
D. 400 kV
Answer» D. 400 kV
5.

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. Kelvin’s law
B. Ohm’s law
C. Kirchhoffs law
D. Faraday’s law
Answer» A. Kelvin’s law
6.

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

A. from 2 to 5 years
B. 10 to 15 years
C. 25 to 30 years
D. 60 to 70 years
Answer» C. 25 to 30 years
7.

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

A. Copper
B. Aluminium
C. Steel
D. Tungsten
Answer» D. Tungsten
8.

Galvanised steel wire is generally used as

A. stay wire
B. earth wire
C. structural components
D. all of the above
Answer» D. all of the above
9.

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

A. 40—50 meters
B. 60—100 meters
C. 80—100 meters
D. 300—500 meters
Answer» C. 80—100 meters
10.

The corona is considerably affected by which of the following ?

A. Size of the conductor
B. Shape of the conductor
C. Surface condition of the conductor
D. All of the above
Answer» D. All of the above
11.

Which of the following are the constants of the transmission lines ?

A. Resistance
B. Inductance
C. Capacitance
D. All of the above
Answer» D. All of the above
12.

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
13.

The phenomenon qf rise in voltage at the receiving end of the open-circuited or lightly loaded line is called the

A. Seeback effect
B. Ferranti effect
C. Raman effect
D. none of the above
Answer» B. Ferranti effect
14.

The square root of the ratio of line impedance and shunt admittance is called the

A. surge impedance of the line
B. conductance of the line
C. regulation of the line
D. none of the above
Answer» A. surge impedance of the line
15.

Which of the following is the demerit of a ‘constant voltage transmission system’ ?

A. Increase of short-circuit current of the system
B. Availability of steady voltage at all loads at the line terminals
C. Possibility of better protection for the line due to possible use of higher terminal reactants
D. Improvement of power factor at times of moderate and heavy loads
Answer» A. Increase of short-circuit current of the system
16.

The operating voltage of high voltage cables is up to

A. l.lkV
B. 3.3kV
C. 6.6kV
D. llkV
Answer» D. llkV
17.

The operating voltage of supertension cables is up to

A. 3.3 kV
B. 6.6 kV
C. 11 kV
D. 33 kV
Answer» D. 33 kV
18.

The operating voltage of extra high tension cables is upto

A. 6.6 kV
B. 11 kV
C. 33 kV
D. 66 kV
Answer» D. 66 kV
19.

Which of the following methods is used for laying of underground cables ?

A. Direct laying
B. Draw-in-system
C. Solid system
D. All of the above
Answer» D. All of the above
20.

Which of the following is the source of heat generation in the cables ?

A. Dielectric losses in cable insulation
B. losses in the conductor
C. Losses in the metallic sheathings and armourings
D. All of the above
Answer» D. All of the above
21.

Due to which of the following reasons the cables should not be operated too hot ?

A. The oil may loose its viscosity and it may start drawing off from higher levels
B. Expansion of the oil may cause the sheath to burst
C. Unequal expansion may create voids in the insulation which will lead to ionization
D. All of the above
Answer» D. All of the above
22.

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

A. Radial system
B. Ring system
C. Inter-connected system
D. None of the above
Answer» A. Radial system
23.

A booster is a

A. series wound generator
B. shunt wound generator
C. synchronous generator
D. none of the above
Answer» A. series wound generator
24.

Besides a method of trial and error, which of the following methods is employed for solution of network problems in interconnected system ?

A. Circulating current method
B. Thevenin’s theorem
C. Superposition of currents
D. All of the above
Answer» D. All of the above
25.

Which of the following faults is most likely to occur in cables ?

A. Cross or short-circuit fault
B. Open circuit fault
C. Breakdown of cable insulation
D. All of the above
Answer» D. All of the above
26.

The cause of damage to the lead sheath of a cable is

A. crystallisation of the lead through vibration
B. chemical action on the lead when buried in the earth
C. mechanical damage
D. all of the above
Answer» D. all of the above
27.

The voltage of the single phase supply to residential consumers is

A. 110 V
B. 210 V
C. 230 V
D. 400 V
Answer» C. 230 V
28.

Most of the high voltage transmission lines in India are

A. underground
B. overhead
C. either of the above
D. none of the above
Answer» B. overhead
29.

The distributors for residential areas are

A. single phase
B. three-phase three wire
C. three-phase four wire
D. none of the above
Answer» C. three-phase four wire
30.

The conductors of the overhead lines are

A. solid
B. stranded
C. both solid and stranded
D. none of the above
Answer» B. stranded
31.

High voltage transmission lines use

A. suspension insulators
B. pin insulators
C. both (a) and (b)
D. none of the above
Answer» A. suspension insulators
32.

Multicore cables generally use

A. square conductors
B. circular conductors
C. rectangular conductors
D. sector-shaped conductors
Answer» D. sector-shaped conductors
33.

Distribution lines in India generally use

A. wooden poles
B. R.C.C. poles
C. steel towers
D. none of the above
Answer» B. R.C.C. poles
34.

The material commonly used for insulation in high voltage cables is

A. lead
B. paper
C. rubber
D. none of the above
Answer» B. paper
35.

The loads on distributors systems are generally

A. balanced
B. unbalanced
C. either of the above
D. none of the above
Answer» B. unbalanced
36.

The power factor of industrial loads is generally

A. unity
B. lagging
C. leading
D. zero
Answer» B. lagging
37.

Overhead lines generally use

A. copper conductors
B. all aluminium conductors
C. A.C.S.R. conductors
D. none of these
Answer» C. A.C.S.R. conductors
38.

In transmission lines the cross-arms are made of

A. copper
B. wood
C. R.C.C.
D. steel
Answer» D. steel
39.

The material generally used for armour of high voltage cables is

A. aluminium
B. steel
C. brass
D. copper
Answer» B. steel
40.

Transmission line insulators are made of

A. glass
B. porcelain
C. iron
D. P.V.C.
Answer» B. porcelain
41.

The material commonly used for sheaths of underground cables is

A. lead
B. rubber
C. copper
D. iron
Answer» A. lead
42.

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

A. 4.3 m
B. 5.5 m
C. 7.0 m
D. 10.5 m
Answer» C. 7.0 m
43.

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

A. 2 m
B. 3.5 m
C. 6 m
D. 8.5 m
Answer» C. 6 m
44.

Large industrial consumers are supplied electrical energy at

A. 400 V
B. 11 kV
C. 66 kV
D. 400 kV
Answer» C. 66 kV
45.

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

A. boost the generated voltage
B. balance loads on both sides of the neutral
C. make both machine^ run as unloaded motors
D. equalize voltages on the positive and negative outers
Answer» D. equalize voltages on the positive and negative outers
46.

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

A. both balancers run as generators
B. both balancers run as motors
C. balancer connected to lightly- loaded side runs as a motor
D. balancer connected to heavily- loaded side runs as a motor
Answer» D. balancer connected to heavily- loaded side runs as a motor
47.

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

A. 25 percent
B. 50 percent
C. 75 percent
D. 100 percent
Answer» B. 50 percent
48.

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. one-fourth
49.

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

A. 31.25 percent of copper
B. 33.3 percent of copper
C. 66.7 percent of copper
D. 125 percent of copper
Answer» A. 31.25 percent of copper
50.

Which of the following is usually not the generating voltage ?

A. 6.6 kV
B. 8.8 kV
C. 11 kV
D. 13.2 kV
Answer» B. 8.8 kV

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