1. The topmost conductor in hv
transmission line is
a) B-phase conductor
b)
Y- phase conductor
c)
R- phase conductor
d)
Earth conductor
Ans: (d)
2. Corona has the
disadvantage(s) of
a) Power loss
b)
Introduction with neighbouring communication circuits
c) Introducing the harmonics,
predominately third harmonics, into transmission lines
d)
All of these
Ans: (d)
3. Insulators used on EHT
transmission lines are
a) PVC
b)
Glass
c)
Stealite
d)
Porcelain
Ans: (d)
4. The dielectric strength of
air under normal conditions is around
a) 30 kV/cm.
b)
150 kV/cm.
c)
100 kV /cm.
d) 200 kV/cm Ans: (a)
5. The insulators used on 220
kV transmission lines are of
a) Suspension type
b)
Pin type
c)
Shackle type
d)
None of these
Ans: (a)
6. Power loss due to corona is
directly proportional to
a) Radius of conductor
b)
Supply frequency
c)
Spacing between conductors.
d)
None of these
Ans: (b)
7. HV transmission line uses
a) Pine type insulators
b)
Suspension insulators
c)
Both (a) and (b)
d)
None of these
Ans: (c)
8. Corona occurs between two
transmission conductors when they
a) Have high potential difference
b)
Are closely spaced
c)
Carry dc power
d) Both (a)
and (b) Ans: (d)
9. Critical voltage limit of a
transmission line is increased by
a) Reducing the radius of the conductors
b)
Reducing the spacing between conductors
c) Increasing the spacing
between conductors
d)
Increasing the radius of the conductors
Ans: (d)
10. Which of the following
affects the corona least?
a) Size and charge per ion
b)
Number of ions
c)
Atmospheric temperature
d)
Mean free length
Ans: (c)
11. Transmission line constants are
a) Capacitance
b)
Inductance
c)
Resistance
d)
All of these
Ans: (d)
12.
The effect of corona is
a) Increased inductance
b)
Increased reactance
c) Increased power loss
d) All of these Ans: (c)
13.
The inductance of line is minimum when
a) G M D is high
b)
G M R is high
c)
Both G M D and G M R are high
d)
G M D is low but G M R is high
Ans: (d)
14. Corona is affected by
a) Size of conductor
b)
Shape and surface condition of the conductor
c)
Operating voltage
d) All of these Ans: (d)
15.
The inductance of single phase two wire power
transmission line per km gets doubled when the
a) Radius of the wore is double
b)
Distance between the wires is increased as square of the original distance
c)
Distance between the wires is doubled
d) Distance
between the wires is doubled Ans: (b)
16.
Capacitance of a transmission line
a) Increases
b)
Decreases
c)
Remains same with increase in its length
d) None of these Ans: (a)
17.
The only advantage of corona is that
is
a) Ozone gas is produced
b)
works as a safety valve for surges
c)
makes line current sinusoidal
d)
produces a pleasing luminous glow
Ans: (b)
18.
Compared with solid conductor of the same radius,
corona appears on a stranded conductor at a lower voltage, because stranding
a)
assists ionization
b)
makes the current flow spirally about the axis of the conductor
c)
produces oblique sections to a plane perpendicular to the axis of the conductor
d)
produces surfaces of smaller radius
Ans: (d)
19. The skin effect of a
conductor reduces with the increase in
a) permeability of conductor material
b)
x-section of conductor
c)
Resistivity of the conductor material
d)
Supply frequency
Ans: (c)
20. High voltage transmission
lines are transposed because then
a) Phase voltage imbalances can
be minimized
b)
Voltage drop in the lines can be minimized
c)
Computations of inductance becomes easier
d) Corona
losses can be minimized Ans: (a)
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