On which of the following factors skin effect depends ?

Resistivity of the conductor material

A conductor consisting of a centre core of steel surrounded by layers of aluminium is named as:

Aluminium Conductor Steel Reinforced

A power line is coupled capacitively through various parasitic capacitances to a shielded signal line as shown in the figure. The conductive shield is grounded solidly at one end. Assume that the length of the signal wire extending beyond the shield, and the shield resistance are negligible. The magnitude of the noise voltage coupled to the signal line is

inversely proportional to the power line frequency

In a cable voltage stress is maximum

At the surface of the insulator

At the surface of the armouring

At the surface of the conductor

For the transmission of power, a direct drive is only preferred when:

the high speed motor is to drive a low speed machine

the speed of the driven machine equals the motor speed

the high speed motor is to drive a low speed machine

a noiseless, slipless and smooth operation is required

A steel- cored aluminium conductor consists of central core of _______ wires surrounded by a number of: _____.

galvanised steel; aluminium strands

Transformer has lowest insulation level

Lighting arrester has lowest insulation level

Transformer has lowest insulation level

Bus bar has lowest insulation level

Insulation level of lightning arrester, transformer and bus bar must be same

As compared to single conductor, the bundled conductor transmission lines have

Higher values of surge impedance

Lower values of surge impedance

Higher values of surge impedance

In the case of nominal – T representation of medium length transmission lines, the shunt capacitance can be

assumed to be equally lumped at each end of the line

assume to be distributed throughout the length

assumed to be lumped at the middle of the line

In the loaded-frequency control system with tree governor action, the increase in load demand under steady condition is met,

partly by increased generation and partly by decrease of load demand

only by decrease of load demand due to drop in system frequency

only by increased generation due to opening of steam valve

partly by increased generation and partly by decrease of load demand

partly by increased generation and partly by increased generator excitation

Insulation resistance of a straight cable is:

Directly proportional to the length of cable

Inversely proportional to the length of cable

Ferranti effect in transmission lines is due to the presence of

line resistance and capacitance

line capacitance and inductance

line resistance and capacitance

If a medium transmission line is represented by nominal T, the value of B of ABCD constant is

\(\left( {1 + \frac{1}{2}YZ} \right)\)

\(Y\left( {1 + \frac{1}{4}YZ} \right)\)

\(Z\left( {1 + \frac{1}{4}YZ} \right)\)

\(\left( {1 + \frac{1}{2}YZ} \right)\)

517 + Mcqs in Transmission And Distribution in Electrical Engineering Page 2 McqOptions

51.	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» E.

Discussion

52.	Which of the following are the constants of the transmission lines ?
A.	Resistance
B.	Inductance
C.	Capacitance
D.	All of the above
Answer» E.

Discussion

53.	The phenomenon qf rise in voltage at the receiving end of the open-circuited or lightlyloaded line is called the
A.	Seeback effect
B.	Ferranti effect
C.	Raman effect
D.	none of the above
Answer» C. Raman effect

Discussion

54.	Which of the following materials is not used for transmission and distribution ofelectrical power ?
A.	Copper
B.	Aluminium
C.	Steel
D.	Tungsten
Answer» E.

Discussion

55.	Which of the following materials is used for overhead transmission lines ?
A.	Steel cored aluminium
B.	Galvanised steel
C.	Cadmium copper
D.	Any of the above
Answer» E.

Discussion

56.	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» E.

Discussion

57.	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 statementis known as
A.	Kelvin's law
B.	Ohm's law
C.	Kirchhoffs law
D.	Faraday's law
Answer» B. Ohm's law

Discussion

58.	Which of the following distribution systems is more reliable ?
A.	Radial system
B.	Tree system
C.	Ring main system
D.	All are equally reliable
Answer» D. All are equally reliable

Discussion

59.	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» B. one-third

Discussion

60.	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» E.

Discussion

61.	The wooden poles well impregnated with creosite oil or any preservative compoundhave life
A.	from 2 to 5 years
B.	10 to 15 years
C.	25 to 30 years
D.	60 to 70 years
Answer» D. 60 to 70 years

Discussion

62.	Which of the followingbus-bar schemes has the lowest cost ?
A.	Ring bus-bar scheme
B.	Single bus-bar scheme
C.	Breaker and a half scheme
D.	Main and transfer scheme
Answer» C. Breaker and a half scheme

Discussion

63.	By which of the following methods string efficiency can be improved ?
A.	Using a guard ring
B.	Grading the insulator
C.	Using long cross arm
D.	Any of the above
Answer» E.

Discussion

64.	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» E.

Discussion

65.	A conductor consisting of a centre core of steel surrounded by layers of aluminium is named as:
A.	Aluminium Conductor
B.	All Aluminium Conductor
C.	All Aluminium Alloy Conductor
D.	Aluminium Conductor Steel Reinforced
Answer» E.

Discussion

66.	A power line is coupled capacitively through various parasitic capacitances to a shielded signal line as shown in the figure. The conductive shield is grounded solidly at one end. Assume that the length of the signal wire extending beyond the shield, and the shield resistance are negligible. The magnitude of the noise voltage coupled to the signal line is
A.	directly proportional to C1G
B.	inversely proportional to the power line frequency
C.	inversely proportional to C1S
D.	zero
Answer» E.

Discussion

67.	Grading of cable is preferred in order to achievea. uniform stressb. reduction in the quantity of insulationc. reduction in the quality of insulation
A.	a and b only
B.	b only
C.	a and c only
D.	b and c only
Answer» B. b only

Discussion

68.	A C.S.R conductor having 7 steel strands surrounded by 25 aluminium conductors will be specified as
A.	25/7
B.	7/25
C.	50/15
D.	15/50
Answer» B. 7/25

Discussion

69.	HT cables are generally used up to
A.	11 kV
B.	33 kV
C.	66 kV
D.	132 kV
Answer» B. 33 kV

Discussion

70.	In a cable voltage stress is maximum
A.	At the surface of the insulator
B.	At the surface of the armouring
C.	At the surface of the sheath
D.	At the surface of the conductor
Answer» E.

Discussion

71.	A long transmission line has a large capacitance. If such a line is open-circuited or connected to the very light load at the receiving end, the magnitude of the voltage at the receiving end becomes higher than the voltage at the sending end. Such a phenomenon is called:
A.	Skin effect
B.	Corona loss
C.	Ferranti effect
D.	Sag in transmission lines
Answer» D. Sag in transmission lines

Discussion

72.	For the same conductor length, same amount of power, same losses and same maximum voltage to earth, which system requires minimum conductor area?
A.	Single-phase ac
B.	3 wire DC
C.	2-phase ac
D.	3 wire AC
Answer» C. 2-phase ac

Discussion

73.	In a distribution system, major cost is that of
A.	Earthing system
B.	Distribution transformer
C.	Conductors
D.	Meters
Answer» C. Conductors

Discussion

74.	Fig. below shows a 2 wire DC distributor cable AC of 4 km long supplying loads of 100 A and 200 A at distances of 2 km and 4 km from A. The feeder is fed at point A with a voltage of 500 V. The voltage available at the farthest point in the system is ______.(Assume conductor resistance per km as 0.02 Ω).
A.	470 V
B.	460 V
C.	476 V
D.	480 V
Answer» C. 476 V

Discussion

75.	Overhead transmission lines are transposed because
A.	Efficiency improves
B.	Voltage regulation improves
C.	Unbalance reduces
D.	None of the above
Answer» D. None of the above

Discussion

76.	For the transmission of power, a direct drive is only preferred when:
A.	the slip is negligible
B.	the speed of the driven machine equals the motor speed
C.	the high speed motor is to drive a low speed machine
D.	a noiseless, slipless and smooth operation is required
Answer» C. the high speed motor is to drive a low speed machine

Discussion

77.	In the overhead system the maximum disruptive stress exists between the:
A.	Phase conductor and neutral
B.	Conductor and the earth
C.	Conductors
D.	Conductor and pole
Answer» C. Conductors

Discussion

78.	Least number of faults occur in:
A.	Transmission lines
B.	Cables
C.	Switchgears
D.	Transformers
Answer» C. Switchgears

Discussion

79.	Conductors experience skin effect in
A.	HVDC transmission
B.	AC transmission
C.	Both AC and DC transmissions
D.	DC transmission
Answer» C. Both AC and DC transmissions

Discussion

80.	A short transmission line, having its line impedance angles as θ, is delivering a given power at the receiving end at a lagging power factor angle of ϕ. Which one of the following a set of conditions for which this line will have maximum and zero regulation respectively?
A.	ϕ = θ, ϕ - θ = π/2
B.	ϕ - θ = π/2, ϕ = θ
C.	ϕ = θ, ϕ + θ = π/2
D.	ϕ + θ = π/2, ϕ = θ
Answer» D. ϕ + θ = π/2, ϕ = θ

Discussion

81.	A two-wire 1000-m-long DC distributor cable is loaded with 0.5 A/m. The resistance of each of the conductors is 0.05 Ω/km. If the distributor is fed from both ends with equal voltages of 220 V, the maximum voltage drop will be:
A.	4.8 V
B.	5.2 V
C.	6.25 V
D.	2.4 V
Answer» D. 2.4 V

Discussion

82.	A steel- cored aluminium conductor consists of central core of _______ wires surrounded by a number of: _____.
A.	galvanised steel; aluminium strands
B.	copper; aluminium strands
C.	aluminium; copper strands
D.	aluminium; steel strands
Answer» B. copper; aluminium strands

Discussion

83.	A consumer is taking load of 20 kW at power factor of 0.8 lagging. Find the rating of capacitor to rise the power factor to 0.95.
A.	9.43 kVAR
B.	8.43 kVAR
C.	7.53 kVAR
D.	6.43 kVAR
Answer» C. 7.53 kVAR

Discussion

84.	Insulators are made of which material?
A.	Porcelain
B.	Rubber
C.	Glass
D.	Styrofoam
Answer» B. Rubber

Discussion

85.	In a substation
A.	Lighting arrester has lowest insulation level
B.	Transformer has lowest insulation level
C.	Bus bar has lowest insulation level
D.	Insulation level of lightning arrester, transformer and bus bar must be same
Answer» B. Transformer has lowest insulation level

Discussion

86.	One of the principal reason for the widespread use of A.C. power system is the availability of
A.	the transformer
B.	the moving iron instrument
C.	the transmission lines
D.	large quantity of power
Answer» B. the moving iron instrument

Discussion

87.	Phase advancers are used with induction motors to
A.	Reduce noise
B.	Reduce vibrations
C.	Reduce copper losses
D.	Improve power factor
Answer» E.

Discussion

88.	A load is supplied by a 230 V, 50 Hz source. The active power P and the reactive power Q consumed by the load are such that 1 kW ≤ P ≤ 2 kW and 1 kVAR ≤ Q ≤ 2 kVAR. A capacitor connected across the load for power factor correction generates 1 kVAR reactive power. The worst case power factor after power factor connection is
A.	0.447 lag
B.	0.707 lag
C.	0.894 lag
D.	1
Answer» C. 0.894 lag

Discussion

89.	As compared to single conductor, the bundled conductor transmission lines have
A.	Lower values of surge impedance
B.	Higher values of surge impedance
C.	Zero surge impedance
D.	Infinite surge impedance
Answer» B. Higher values of surge impedance

Discussion

90.	In series compensation, if the degree of compensation is 0.5, then the power transfer capability of transmission line with compensation will be __________ times the power transfer capability without compensation.
A.	2
B.	3
C.	4
D.	0.5
Answer» B. 3

Discussion

91.	One among the following is the top most conductors in high voltage transmission lines, identify it.
A.	R - phase conductor
B.	Y - phase conductor
C.	B - phase conductor
D.	Earth conductor
Answer» E.

Discussion

92.	In the case of nominal – T representation of medium length transmission lines, the shunt capacitance can be
A.	assumed to be equally lumped at each end of the line
B.	assume to be distributed throughout the length
C.	neglected
D.	assumed to be lumped at the middle of the line
Answer» E.

Discussion

93.	In the loaded-frequency control system with tree governor action, the increase in load demand under steady condition is met,
A.	only by decrease of load demand due to drop in system frequency
B.	only by increased generation due to opening of steam valve
C.	partly by increased generation and partly by decrease of load demand
D.	partly by increased generation and partly by increased generator excitation
Answer» C. partly by increased generation and partly by decrease of load demand

Discussion

94.	A cable has insulation of relative permittivity 2. If the insulation is replaced by one of relative permittivity 4, the capacitance of the cable will become
A.	one fourth
B.	half
C.	double
D.	four times
Answer» D. four times

Discussion

95.	Insulation resistance of a straight cable is:
A.	Zero
B.	Directly proportional to the length of cable
C.	Inversely proportional to the length of cable
D.	One
Answer» D. One

Discussion

96.	Ferranti effect in transmission lines is due to the presence of
A.	line inductance
B.	line capacitance
C.	line capacitance and inductance
D.	line resistance and capacitance
Answer» D. line resistance and capacitance

Discussion

97.	A distribution feeder of 1 km length having resistance, but negligible reactance, is fed from both the ends by 400 V, 50 Hz balanced sources. Both voltage sources S1 and S2 are in phase. The feeder supplies concentrated loads of unity power factor as shown in the figure.The contributions of S1 and S2 in 100 A current supplied at location P respectively, are
A.	75 A and 25 A
B.	50 A and 50 A
C.	25 A and 75 A
D.	0 A and 100 A
Answer» E.

Discussion

98.	If a medium transmission line is represented by nominal T, the value of B of ABCD constant is
A.	Z
B.	\(Y\left( {1 + \frac{1}{4}YZ} \right)\)
C.	\(Z\left( {1 + \frac{1}{4}YZ} \right)\)
D.	\(\left( {1 + \frac{1}{2}YZ} \right)\)
Answer» D. \(\left( {1 + \frac{1}{2}YZ} \right)\)

Discussion

99.	In a long or medium transmission line, the phenomenon causing receiving end voltage to be greater than sending end voltage under no-load condition is called:
A.	skin effect
B.	Corona effect
C.	loading effect
D.	Ferranti effect
Answer» E.

Discussion

100.	Consider the following statementsHigh voltage is used in long-distance power transmission in order to:A) Reduce the time of transmissionB) Reduce the transmission lossesC) Make the system reliableOut of these, the correct statements are?
A.	Only B
B.	All three
C.	Only A and B
D.	Only A and C
Answer» B. All three

Discussion

Explore topic-wise MCQs in Electrical Engineering.

Which of the following equipment, for regulating the voltage in distribution feeder,will be most economical ?

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

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

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

Which of the following materials is used for overhead transmission lines ?

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

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 statementis known as

Which of the following distribution systems is more reliable ?

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

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

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

Which of the followingbus-bar schemes has the lowest cost ?

By which of the following methods string efficiency can be improved ?

On which of the following factors skin effect depends ?

A conductor consisting of a centre core of steel surrounded by layers of aluminium is named as:

Grading of cable is preferred in order to achievea. uniform stressb. reduction in the quantity of insulationc. reduction in the quality of insulation

A C.S.R conductor having 7 steel strands surrounded by 25 aluminium conductors will be specified as

HT cables are generally used up to

In a cable voltage stress is maximum

A long transmission line has a large capacitance. If such a line is open-circuited or connected to the very light load at the receiving end, the magnitude of the voltage at the receiving end becomes higher than the voltage at the sending end. Such a phenomenon is called:

For the same conductor length, same amount of power, same losses and same maximum voltage to earth, which system requires minimum conductor area?

In a distribution system, major cost is that of

Overhead transmission lines are transposed because

For the transmission of power, a direct drive is only preferred when:

In the overhead system the maximum disruptive stress exists between the:

Least number of faults occur in:

Conductors experience skin effect in

A short transmission line, having its line impedance angles as θ, is delivering a given power at the receiving end at a lagging power factor angle of ϕ. Which one of the following a set of conditions for which this line will have maximum and zero regulation respectively?

A two-wire 1000-m-long DC distributor cable is loaded with 0.5 A/m. The resistance of each of the conductors is 0.05 Ω/km. If the distributor is fed from both ends with equal voltages of 220 V, the maximum voltage drop will be:

A steel- cored aluminium conductor consists of central core of _______ wires surrounded by a number of:­­­ ­_____.

A consumer is taking load of 20 kW at power factor of 0.8 lagging. Find the rating of capacitor to rise the power factor to 0.95.

Insulators are made of which material?

In a substation

One of the principal reason for the widespread use of A.C. power system is the availability of

Phase advancers are used with induction motors to

As compared to single conductor, the bundled conductor transmission lines have

In series compensation, if the degree of compensation is 0.5, then the power transfer capability of transmission line with compensation will be __________ times the power transfer capability without compensation.

One among the following is the top most conductors in high voltage transmission lines, identify it.

In the case of nominal – T representation of medium length transmission lines, the shunt capacitance can be

In the loaded-frequency control system with tree governor action, the increase in load demand under steady condition is met,

A cable has insulation of relative permittivity 2. If the insulation is replaced by one of relative permittivity 4, the capacitance of the cable will become

Insulation resistance of a straight cable is:

Ferranti effect in transmission lines is due to the presence of

If a medium transmission line is represented by nominal T, the value of B of ABCD constant is

In a long or medium transmission line, the phenomenon causing receiving end voltage to be greater than sending end voltage under no-load condition is called:

Consider the following statementsHigh voltage is used in long-distance power transmission in order to:A) Reduce the time of transmissionB) Reduce the transmission lossesC) Make the system reliableOut of these, the correct statements are?

A steel- cored aluminium conductor consists of central core of ___ wires surrounded by a number of: _.