400 Important Transmission and Distribution MCQ Question and Answer | PDF Free Download
1.The corona effect can be minimized by increasing
- ASpacing between conductors
- BThe length of conductor
- CDiameter of conductors
- DBoth spacing between conductors and diameter of the conductors
2.Corona losses in transmission lines are minimized when
- AConductor size is reduced
- BSmooth conductor is used
- CSharp points are provided in the line hardware
- DCurrent density in conductor is reduced
3.The corona loss on a particular system at 50 Hz is 1kW/km per phase. What is the corona loss at 60 Hz in kW/km per phase ?
- A0.83
- B1.0
- C1.13
- D1.2
4.In a transmission line the distributed constants are
- AResistance and shunt conductance only
- BResistance and inductance only
- CResistance, inductance and capacitance only
- DResistance, inductance, capacitance and shunt conductance
5.Skin effect depends upon
- AX-section of conductor
- BSupply frequency
- CPermeability of conductor material
- DAll of the above
6.Skin effect in transmission line is due to
- ASupply frequency
- BSelf-inductance of conductor
- CHigh sensitivity of material in the centre
- DBoth (a) and (b)
7.Increasing the frequency of transmission line will
- AIncrease shunt reactance
- BDecrease line resistance
- CIncrease line resistance
- DDecrease series reactance
8.Skin effect exists in
- ACable carrying DC current
- BDC transmission line only
- CAC transmission line only
- DDC as well as AC transmission line
9.Skin effect
- AIncreases the effective resistance and effective internal reactance
- BReduces the effective resistance and effective internal reactance
- CIncreases the effective resistance but reduces the effective internal reactance
- DReduces the effective resistance but increases the effective internal reactance
10.The skin effect of a conductor reduces with the increase in
- ASupply frequency
- BResistivity of the conductor material
- CX-section of conductor
- DPermeability of conductor material
11.In order to reduce the skin effect at UHF
- ACopper tubes with silver plating are used
- BCopper rods with silver plating are used
- CAnodised conductors are used
- DPainted conductors are used
12.A 100 km long transmission line is loaded at 110 kV . if the loss of line is 15 MW and the load is 150 MVA, the resistance of the line is
- A8.06 ohms per phase
- B0.806 ohms per phase
- C0.0806 ohms per phase
- D80.6 ohms per phase
13.Consider a long, two-wire line composed of solid round conductors. The radius of both conductors is 0.25 cm and the distance between their centres is 1 m. if this distance is doubled, then the inductance per unit length.
- ADoubles
- BHalves
- CIncreases but does not double
- DDecreases but does not halve
14.The inductance of single-phase two-wire power transmission line per km gets doubled when the
- ADistance between the wires is doubled
- BDistance between the wires is increased four fold
- CDistance between the wires is increased as square of the original distance
- DRadius of the wire is doubled
15.For 11 kV line, the inductance per km per phase will be of the order of
- A1 H
- B0.1 H
- C1 mH
- D0.1 mH
16.A 3-phase transmission line has its conductors at the corners of an equilateral triangle with side 3 m. the diameter of each conductor is 1.63 cm. the inductance of the line per phase per km is
- A1.232 mH
- B0.182 mH
- C1.093 mH
- D1.043 mH
17.The conductors of a 10 km long, single-phase, 2-wire line are separated by a distance of 1.5 m. the diameter of each conductor is 1 cm. if the conductors are of coper, the inductance of the circuit is
- A50.0 mH
- B45.3 mH
- C23.8 mH
- D19.6 mH
18.The inductance of a power transmission line increases with
- ADecrease in line length
- BIncrease in diameter of conductor
- CIncrease in spacing between the phase conductors
- DIncrease in load current carried by the conductors
19.The inductance of a transmission line minimum when
- AGMD is high
- BGMR is high
- CBoth GMD and GMR are high
- DGMD is low and GMR is high
20.Hollow conductors are used in transmission lines to
- AReduce weight of copper
- BImprove stability
- CReduce corona
- DIncrease power transmission capacity