Transmission and distribution mcq
transmission and distribution electrical Multiple Choice Questions :-
transmission and distribution electrical Multiple Choice Questions :-
1. The usual spans with R.C.C. poles are -
(a) 30—40 meters
(b) 90—100 meters
(c) 80—100 meters
(d) 400—500 meters
Ans: c
2.
Which of the following materials is not used for transmission and
distribution of electrical power ?
(a)
Lead
(b)
Aluminium
(c)
Nickel
(d)
Tungsten
Ans:
d
3.
The wooden poles well impregnated with creosite oil or any preservativecompound
have life-----
(a)
from 5 to 8 years
(b)
25 to 30 years
(c)
10 to 30 years
(d)
50 to 70 years
Ans:
b
4. 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 sizeof conductor will be most economical. This statement
is known as –
(a)
Lenz'z law
(b)
Ohm’s law
(c)
Kirchhoffs law
(d)
Kelvin’s law
Ans:-
d
5. By which of the
following systems electric power may be transmitted?
(a)
Underground system
(b)
overhead system
(c)
only (b)
(d) both (a) and (b)
Ans-
d
6. The
underground system cannot be operated above
(a)
66 V
(b)132kV
(c)
11 kV
(d)33kV
Ans:-
a
7. Overhead
system can be designed for operation up to
(a)132kV
(b)11
kV
(c)
66 kV
(d)
400 kV
Ans:-
write in
comment box
8. 310 km line is considered
as
(a)
a short line
(b)
a medium line
(c)
a long line
(d)
none of the above
Ans:
c
9. Which of the
following are the constants of the transmission lines----
(a)
Resistance
(b)
Inductance
(c)
Capacitance
(d)
none of the above
Ans:
d
10. The
corona is 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
Ans:
d
11. Galvanised
steel wire is used as -
(a)
stay wire
(b)
earth wire
(c)
structural components
(d)
All of the above
Ans:-
d
12. The
square root of the ratio of line impedance and shunt admittance is called
(a) conductance of the line
(b)
surge impedance of the line
(c)
regulation of the line
(d)
all of the above
Ans:
b
13. The
phenomenon qf rise in voltage at the receiving end of the open-circuited or
lightly loaded line is called
(a) Ferranti effect
(b)
Doppler effect
(c)
Raman effect
(d)
all of the above
Ans:-
a
14.
conductors, which connect the consumer’s terminals to the distribution
(a) Feeders
(b) Distributors
(c) Service mains
(d) None of the
above
Ans:c
15. The operating
voltage of supertension cables is up to
(a)
1.1 kV
(b)
6.6 kV
(c)
33 kV
(d)
11 kV
Ans:-
c
16. Which
of the following methods is used for laying of underground cables
(a)
Solid system
(b)Direct laying
(c)
Draw-in-system
(d) All of the above
Ans:
d
17. The
operating voltage of extra high tension cables is upto
(a)
6.6 kV
(b)
66 kV
(c)
33 kV
(d)
132 kV
Ans:
b
18. 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
Ans:
- write in comment box
19. Which of the
following D.C. distribution system is the simplest and lowest in first cost?
(a)
Ring system
(b)
Inter-connected system
(c)
Radial system
(d)
None of the above
Ans:-
a
20. A booster is a
--
(a)
synchronous generator
(b) shunt wound generator
(c)
series wound generator
(d)
All of the above
Ans:
c
21. The voltage of the single phase supply to
residential consumers is
(a)
200 V
(b)
120 V
(c)
440 V
(d)
230 V
Ans:-
d
22. 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
Ans: d
23. The
distributors for residential areas are
(a)
single phase
(b)
three-phase four wire
(c)
three-phase three wire
(d)
all of the above
Ans:
b
24. The cause of
damage to the lead sheath of a cable is
(a)
mechanical damage
(b) chemical action on the lead when buried in
the earth
(c)
crystallisation of the lead through vibration
(d)
all of the above
Ans:
d
25. The conductors
of the overhead lines are
(a) Stranded
(b) Solid
(c)
both solid and stranded
(d)
all of the above
Ans:
a
26. Multicore
cables generally use
(a)
square conductors
(b)
circular conductors
(c)
sector-shaped conductors
(d)
rectangular conductors
Ans:-
c
27. High voltage
transmission lines use
(a) pin insulators
(b)
suspension insulators
(c)
both (a) and (b)
(d)
all of the above
Ans:-
b
28. The material
commonly used for insulation in high voltage cables is
(a)
paper
(b) rubber
(c)
lead
(d)
graphite
Ans:-
a
29. The loads on
distributors systems are
(a)
balanced
(b)
unbalanced
(c)
both balanced and unbalanced
(d)
none of the above
Ans:
b
30. Overhead lines
generally use
(a)
copper conductors
(b)
All aluminium conductors
(c)
Aluminium conductor steel-reinforcement
(d)
Nickel coated copper
Ans:
c
31. The power
factor of industrial loads is generally
(a) zero
(b) leading
(c) unity
(d) lagging
Ans:-
d
32. Transmission
line insulators are made of
(a)
porcelain
(b)
iron
(C)
glass
(d)
P.V.C.
Ans:
a
33. The material
generally used for armour of high voltage cables is
(a)
copper
(b)
brass
(c)
aluminium
(d) steel
Ans:-
d
34. The minimum
clearance between the ground and a 220 kV line is about
(a)
7.0m
(b)
7.5 m
(c)
8.0m
(d)
8.5 m
Ans:
a
35. Large
industrial consumers are supplied electrical energy at
(a)
132 kV
(b)
33 kV
(c)
400 kV
(d)
66 kV
Ans:-
d
36. For an overhead
line, the surge impedance is taken as
(a)
10-30 ohms
(b)
100—200 ohms
(c)
300—400 ohms
(d)
700—1000 ohms
Ans:
b
37. A feeder, in a
transmission system, feeds power to
(a)
service mains
(b)
generating stations
(c)
distributors
(d)
none of the above
Ans:-
c
38. In aluminium
conductors, steel core is provided to
(a) increase the tensile strength
(b) reduce line inductance
(c ) compensate for skin effect
(d) neutralise proximity effect
Ans:- a
39. Aluminium has a
specific gravity of
(a)
2.5
(b)
2.6
(c)
2.7
(d)
2.8
Ans:-
c
40. Pin
type insulators are generally not used for voltages beyond
(a)
33 kV
(b)
66 kV
(c)
132 kV
(d)
400 kV
Ans:-
a
41. For
transmission of power over a distance of 200 km, the transmission voltage
should be
(a)
11 kV
(b)
33 kV
(c)
66 kV
(d)
132 kV
Ans:-
d
42. Series
capacitors on transmission lines are of little use when the load VAR
requirement is
(a)
small
(b)
large
(c)
fluctuating
(d)
none of the above
Ans:
a
43. When a
conductor carries more current on the surface as compared to core, it is due to
(a)
unsymmetrical fault
(b)
skin effect
(c)
corona
(d)
permeability variation
(e)
all of the above
Ans:-
b
44. The skin effect
of a conductor will reduce as the
(a)
frequency increases
(b)
resistivity of conductor material increases
(c)
diameter increases
(d)
permeability of conductor material increases
Ans:-
b
45. The angular
displacement between two interconnected stations is mainly due
(a)
reactance of the interconnector
(b)
armature reactance of both alternators
(c)
synchronous reactance of both the alternators
(d)
none of the above
Ans:
b
46. When the interconnector between two stations
has large reactance
(a) the stations will fall out of step because of
large angular displacement between the stations
(b) the transfer of power will take place with
voltage fluctuation and noise
(c) the
transfer of power will take place with least loss
(d)
all of the above
Ans:-
a
47. Which of the
following equipment, for regulating the voltage in distribution feeder, will be
most economical
(a)
Booster transformer
(b)
Synchronous condenser
(c)
Tap changing transformer
(d) Static condenser
Ans:- a
48. The current
drawn by the line due to corona losses is
(a)
non-sinusoidal
(b)
sinusoidal
(c)
triangular
(d)
square
Ans:-
a
49. Corona usually
occurs when the electrostatic stress in air around the conductor exceeds
(a)
33 kV (r.m.s. value)/cm
(b)
11 kV (r.m.s. value)/cm
(c)
66 kV (maximum value)/cm
(d)
30 kV (maximum value)/cm
Ans:
d
50. Which of the
following characteristics should the line supports for transmission lines
possess ------
(a)
Low cost
(b)
High mechanical strength
(c)
Longer life
(d)
all of the above
Ans:-
d
Posts
No comments:
Post a Comment