Transmission And Distribution Of Electrical Energy Set 4 MCQs

Q1 | jCorona usually occurs when the electrostatic stress in air around the conductor exceeds

6.6 kV (r.m.s. value)/cm

11 kV (r.m.s. value)/cm

22 kV (maximum value)/cm

30 kV (maximum value)/cm

Q2 | The voltage drop, for constant voltage transmission is compensated by installing

inductors

capacitors

synchronous motors

all of above

Q3 | The use of strain type insulators is made where the conductors are

dead ended

at intermediate anchor towers

any of the above

none of the above

Q4 | The current drawn by the line due to corona losses is

non-sinusoidal

sinusoidal

triangular

square

Q5 | Pin type insulators are generally not used for voltages beyond

1 kV

11 kV

22 kV

33 kV

Q6 | Aluminium has a specific gravity of

1.5

2.7

4.2

7.8

Q7 | For transmission of power over a distance of 200 km, the transmission voltage should be

132 kV

66 kV

33 kV

11 kV

Q8 | For aluminium, as compared to copper, all the following factors have higher values except

specific volume

electrical conductivity

co-efficient of linear expansion

resistance per unit length for same cross-section

Q9 | Which of the following equipment, for regulating the voltage in distribution feeder, will bemost economical ?

Static condenser

Synchronous condenser

Tap changing transformer

Booster tr

Q10 | In a tap changing transformer, the tappings are provided on

primary winding

secondary winding

high voltage winding

any of the above

Q11 | Constant voltage transmission entails the following disadvantage

large conductor area is required for same power transmission

short-circuit current of the system is increased

either of the above

none of the above

Q12 | On which of the following factors skin effect depends ?

Frequency of the current

Size of the conductor

Resistivity of the conductor material

All of the above

Q13 | The effect of corona can be detected by

presence of ozone detected by odour

hissing sound

faint luminous glow of bluish colour

all of the above

Q14 | For transmission of power over a distance of 500 km, the transmission voltage should be inthe range

150 to 220 kV

100 to 120 kV

60 to 100 kV

20 to 50 kV

Q15 | In the analysis of which of the following lines shunt capacitance is neglected ?

Short transmission lines

Medium transmission lines

Long transmission lines

Medium as well as long tr

Q16 | When the interconnector between two stations has large reactance

the transfer of power will take place with voltage fluctuation and noise

the transfer of power will take place with least loss

the stations will fall out of step be¬cause of large angular displacement between the stations

none of the above

Q17 | The frequency of voltage generated, in case of generators, can be increased by

using reactors

increasing the load

adjusting the governor

reducing the terminal voltage

Q18 | When an alternator connected to the bus-bar is shut down the bus-bar voltage will

fall

rise

remain unchanged

none of the above

Q19 | The angular displacement between two interconnected stations is mainly due to

armature reactance of both alternators

reactance of the interconnector

synchronous reactance of both the alternators

all of the above

Q20 | Electro-mechanical voltage regulators are generally used in

reactors

generators

transformers

all of the above

Q21 | Series capacitors on transmission lines are of little use when the load VAR requirement is

large

small

fluctuating

any of the above

Q22 | The voltage regulation in magnetic amplifier type voltage regulator is effected by

electromagnetic induction

varying the resistance

varying the reactance

variable tr

Q23 | When a conductor carries more current on the surface as compared to core, it is due to

permeability variation

corona

skin effect

unsymmetrical fault

Q24 | The following system is not generally used

1-phase 3 wire

1-phase 4 wire

3-phase 3 wire

3-phase 4 wire

Q25 | The skin effect of a conductor will reduce as the

resistivity of conductor material increases

permeability of conductor material increases

diameter increases

frequency increases