Question 1

Transmission voltage of llkV is normally used for distances upto

Accepted Answer

A)  20-25 km
B)  40-50 km
C)  60-70 km
D)  80-100 km A

Question 2

A conductor, due to sag between two supports, takes the form of

Accepted Answer

A)  semi-circle
B)  triangle
C)  ellipse
D)  catenary D

Question 3

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

Accepted Answer

A)  inductors
B)  capacitors
C)  synchronous motors
D)  all of above C

Question 4

Skin effect is proportional to

Accepted Answer

A)  (conductor diameter) 
B)  (conductor diameter) .
C)  (conductor diameter) ,
D)  (conductor diameter) ..

Question 5

A 3-phase 4 wire system is commonly used on

Accepted Answer

A)  primary transmission
B)  secondary transmission
C)  primary distribution
D)  secondary distribution

Question 6

Which of the following relays is used on long transmission lines ?

Accepted Answer

A)  Impedance relay
B)  Mho's relay
C)  Reactance relay
D)  None of the above

Question 7

In AC.S.R. conductors, the insulation between aluminium and steel conductors is

Accepted Answer

A)  insulin
B)  bitumen
C)  varnish
D)  no insulation is required

Question 8

By which of the following a bus-bar is rated ?

Accepted Answer

A)  Current only
B)  Current and voltage
C)  Current, voltage and frequency
D)  Current, voltage, frequency and short time current

Question 9

There is a greater possibility of occurence of corona during

Accepted Answer

A)  dry weather
B)  winter
C)  summer heat
D)  humid weather

Question 10

By which of the following methods string efficiency can be improved ?

Accepted Answer

A)  Using a guard ring
B)  Grading the insulator
C)  Using long cross arm
D)  Any of the above

Question 11

A circuit is disconnected by isolators when

Accepted Answer

A)  line is energized
B)  there is no current in the line
C)  line is on full load
D)  circuit breaker is not open

Question 12

The power transmitted will be maximum when

Accepted Answer

A)  corona losses are minimum
B)  reactance is high
C)  sending end voltage is more
D)  receiving end voltage is more

Question 13

Which of the following regulations is considered best?

Accepted Answer

A)  50%
B)  20%
C)  10%
D)  2%

Question 14

In aluminium conductors, steel core is provided to

Accepted Answer

A)  compensate for skin effect
B)  neutralise proximity effect
C)  reduce line inductance
D)  increase the tensile strength

Question 15

The steel used in steel cored conductors is usually

Accepted Answer

A)  alloy steel
B)  stainless steel
C)  mild steel
D)  high speed steel

Question 16

Which of the following materials is used for overhead transmission lines ?

Accepted Answer

A)  Steel cored aluminium
B)  Galvanised steel
C)  Cadmium copper
D)  Any of the above

Question 17

Which of the following characteristics should the line supports for transmission lines possess ?

Accepted Answer

A)  Low cost
B)  High mechanical strength
C)  Longer life
D)  All of the above

Question 18

Which of the followingbus-bar schemes has the lowest cost ?

Accepted Answer

A)  Ring bus-bar scheme
B)  Single bus-bar scheme
C)  Breaker and a half scheme
D)  Main and transfer scheme

Question 19

In a substation the following equipment is not installed

Accepted Answer

A)  exciters
B)  series capacitors
C)  shunt reactors
D)  voltatre transformers

Question 20

Owing to skin effect

Accepted Answer

A)  current flows through the half cross-section of the conductor
B)  portion of the conductor near the surface carries more current and core of the conductor carries less current
C)  portion of the conductor near the surface carries less current and core of the conductor carries more current
D)  any of the above

Exam 3: Transmission System and Equipment