Question 1

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

Accepted Answer

Kelvin's Law states that to achieve the most economical size of a conductor, the annual cost of energy wasted in the conductor should equal the annual cost of interest and depreciation on the capital outlay for the conductor.

Question 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

Accepted Answer

Service mains are the conductors that connect the consumer's terminals to the distribution network, ensuring electricity is delivered from the distribution system to the end user's premises.

Question 3

The underground system cannot be operated above
A)440 V
B)11 kV
C)33 kV
D)66 kV

Accepted Answer

The underground system is typically designed to operate at voltages up to 66 kV. Operating at voltages above 66 kV presents significant challenges and costs for insulation and cooling.

Question 4

Overhead system can be designed for operation upto
A)11 kV
B)33 kV
C)66 kV
D)400 kV

Accepted Answer

The answer of Overhead system can be designed for operation...

Question 5

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

Accepted Answer

Wooden poles that are well impregnated with creosote oil or any preservative compound can have a life expectancy of 25 to 30 years, as these treatments significantly enhance their durability and resistance to decay and pests.

Question 6

Which of the following materials is not used for transmission and distribution of electrical power ?
A)Copper
B)Aluminium
C)Steel
D)Tungsten

Accepted Answer

Tungsten is not used for transmission and distribution of electrical power due to its high cost, high melting point, and relatively lower electrical conductivity compared to copper and aluminium. It is primarily used in applications requiring high temperature resistance, such as in light bulb filaments.

Question 7

Galvanised steel wire is generally used as
A)stay wire
B)earth wire
C)structural components
D)all of the above

Accepted Answer

Galvanized steel wire is versatile and can be used in various applications due to its corrosion resistance. It is commonly used as stay wire for supporting structures, as earth wire for grounding to protect against lightning and electrical surges, and in structural components for added strength and durability.

Question 8

The usual spans with R.C.C. poles are
A)40-50 metres
B)60-100 metres
C)80-100 metres
D)300-500 metres

Accepted Answer

The answer of The usual spans with R.C.C. poles are
A)40-50...

Question 9

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

Accepted Answer

The corona effect is influenced by the size, shape, and surface condition of the conductor, as these factors affect the electric field distribution around the conductor.

Question 10

Which of the following are the constants of the transmission lines ?
A)Resistance
B)Inductance
C)Capacitance
D)All of the above

Accepted Answer

All of the above (Resistance, Inductance, and Capacitance) are considered constants of transmission lines because they define the electrical characteristics of the line under steady-state conditions. Resistance affects power loss, inductance influences the magnetic fields and impedance, and capacitance affects the electric fields and voltage levels along the line.

Question 11

310 km line is considered as
A)a long line
B)a medium line
C)a short line
D)any of the above

Accepted Answer

A transmission line that is 310 km long is considered a long line because it exceeds the typical length (usually around 250 km or more) where line inductance and capacitance significantly affect its performance, necessitating more complex models for accurate analysis.

Question 12

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

Accepted Answer

The Ferranti Effect refers to the increase in voltage observed at the receiving end of a long transmission line when the line is lightly loaded or open-circuited. This phenomenon is due to the capacitive charging currents that lead to a voltage rise over the length of the line.

Question 13

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

Accepted Answer

The square root of the ratio of line impedance (Z) to shunt admittance (Y) is known as the surge impedance of the line. This is a characteristic impedance that plays a crucial role in the analysis of transmission lines, especially for high-frequency or transient conditions.

Question 14

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 reactances
D)Improvement of power factor at times of moderate and heavy loads

Accepted Answer

The demerit of a constant voltage transmission system is the increase of short-circuit current of the system. This is because maintaining a constant voltage regardless of load variations can lead to higher currents during fault conditions, potentially causing more severe damage and complicating protection schemes.

Question 15

Low voltage cables are meant for use up to
A)l.lkV
B)3.3kV
C)6.6kV
D)llkV

Accepted Answer

The answer of Low voltage cables are meant for use...

Question 16

The operating voltage of high voltage cables is upto
A)l.lkV
B)3.3kV
C)6.6kV
D)llkV

Accepted Answer

High voltage cables are typically used for voltages above 1kV, and 11kV is a common operating voltage for high voltage cables.

Question 17

The operating voltage of supertension cables is upto
A)3.3 kV
B)6.6 kV
C)11 kV
D)33 kV

Accepted Answer

Supertension cables are designed for high voltage applications, typically above 33 kV. Therefore, the correct option is D) 33 kV, as it represents the threshold above which cables are considered to be in the supertension category.

Question 18

The operating voltage of extra high tension cables is upto
A)6.6 kV
B)11 kV
C)33 kV
D)66 kV

Accepted Answer

Extra high tension (EHT) cables are designed for operating voltages above 33 kV, up to 66 kV.

Question 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

Accepted Answer

All the mentioned methods, Direct laying, Draw-in-system, and Solid system, are used for laying underground cables.

Question 20

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

Accepted Answer

Operating cables at too high temperatures can lead to several issues, including the loss of oil viscosity, which can cause the oil to draw off from higher levels, the expansion of oil that may cause the sheath to burst, and unequal expansion that may create voids in the insulation, leading to ionization. All these factors can significantly impair the cable's performance and longevity, making it crucial to avoid overheating.

Quiz 1: Electrical Power Transmission and Distribution

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

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

The underground system cannot be operated above

Overhead system can be designed for operation upto

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

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

Galvanised steel wire is generally used as

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

The corona is considerably affected by which of the following ?

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

310 km line is considered as

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

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

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

Low voltage cables are meant for use up to

The operating voltage of high voltage cables is upto

The operating voltage of supertension cables is upto

The operating voltage of extra high tension cables is upto

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

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