EHVAC Objective Question Bank

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Following are the multiple Choice questions for the subject EHVAC and HVDC power transmission systems of final year Electrical Engineering. Students must visit this page repeatedly for updated material.

By increasing the transmission voltage double of its original value, the same power can be dispatched keeping the line loss,
a) Equal to its original value b) Half of original value
c) Double the original value d) One-forth of original value

Ans: d

Which of the following distribution systems is preferred for good efficiency and high economy
a) Single-phase, 2-wire system b) 2-ph, 3-wire system
c) 3-ph, 3-wire system d) 3-ph, 4-wire system

Ans: c

The main reason for using high voltage for long distance power transmission is
a) Reduction in transmission losses b) Reduction in time of transmission
c) Increase in system reliability d) None of the above

Ans: a

The highest transmission voltage used in India is
a) 400 kv b) 220 kv c) 132 kv d) 765 kv

Ans: d

Corona loss in a transmission line is dependent on
a) Diameter of a conductor
b) Material of the conductor
c) Height of the conductor

Ans: a

Corona is
a) Partial breakdown of air
b) Complete breakdown of air
c) Sparking between lines

Ans: c

With bundled conductors
a) The corona inception voltage increases
b) The corona inception voltage decreases
c) The corona inception voltage remain unaffected

Ans: b

Extra high voltage transmission means
a) Voltage less than 400kv
b) Voltage in the range of 400-750kv
c) Voltage grater than 750

Ans: b

Bundled conductors are used for EHV transmission lines primarily for reducing the
a) Corona loss b) Surge impedance
c) Voltage drop across the line d) None of the above

Ans: a

ACSR conductors have
a) All conductors made of aluminium b) Outer conductors made of aluminium
c) Inner conductors made of aluminium d) No conductors made of aluminium

Ans: b

HVDC transmission needs
a) Pulse converters b) Dc generators
c) Ac filters d) Dc filters

Ans: c

A dc line carries
a) Less power than an equivalent ac line
b) More power than the ac line
c) Same power as an ac line

Ans: b

In the case of an HVDC system, there is
a) Charging current but no skin effect b) No charging current but skin effect
c) Neither charging current nor skin effect d) Both charging current and skin effect

Ans: a

For bulk power transmission over long distance HVDC transmission is
a) Is economically and technically superior to ac transmission
b) Not good alternative to ac transmission
c) Not economically viable

Ans: a

Bulk power transmission over long HVDC lines are preferred an account of
a) Low cost of an HVDC terminal
b) No harmonic problem
c) Minimum line power losses
d) Simple protection

Ans: c

As compared to ac transmission dc transmission is free from
a) Inductance b) Capacitance
c) Phase displacement d) All of the above

Ans: d

For power factor improvement static capacitors have the drawback of
a) Short-service life
b) Getting damaged by high voltage
c) Not repairable
d) All of the above

Ans: d

For power factor improvement static capacitors have the advantage of
a) Small losses
b) Easy installation
c) Low initial cost and little maintenance
d) All of the above

Ans: d