Question 1

The use of strain type insulators is made where the conductors are
A)dead ended
B)at intermediate anchor towers
C)any of the above
D)none of the above

Accepted Answer

Strain type insulators are used both where conductors are dead-ended and at intermediate anchor towers to manage the tension in the lines.

Question 2

The current drawn by the line due to corona losses is
A)non-sinusoidal
B)sinusoidal
C)triangular
D)square

Accepted Answer

Corona losses result in a non-sinusoidal current because the corona discharge phenomenon is irregular and does not follow a smooth, sinusoidal pattern. This irregularity is due to the ionization of air around the conductors, which occurs unevenly as the voltage varies.

Question 3

Pin type insulators are generally not used for voltages beyond
A)1 kV
B)11 kV
C)22 kV
D)33 kV

Accepted Answer

Pin type insulators are generally used for voltages up to 33 kV. Beyond this voltage, the mechanical and electrical stresses become too high for pin type insulators, and other types like suspension insulators are preferred.

Question 4

Aluminium has a specific gravity of
A)1.5
B)2.7
C)4.2
D)7.8

Accepted Answer

Aluminium has a specific gravity of approximately 2.7, which is a measure of its density compared to water.

Question 5

For transmission of power over a distance of 200 km, the transmission voltage should be
A)132 kV
B)66 kV
C)33 kV
D)11 kV

Accepted Answer

For transmission of power over long distances, higher voltages are preferred to reduce power losses. A voltage level of 132 kV is suitable for distances around 200 km, as it strikes a balance between reducing losses and the cost of insulation and other equipment.

Question 6

For aluminium, as compared to copper, all the following factors have higher values except
A)specific volume
B)electrical conductivity
C)co-efficient of linear expansion
D)resistance per unit length for same cross-section

Accepted Answer

Aluminum has a lower electrical conductivity compared to copper. Copper is widely used for electrical wiring and applications where high conductivity is required because of its superior electrical conductivity.

Question 7

Which of the following equipment, for regulating the voltage in distribution feeder, will be most economical ?
A)Static condenser
B)Synchronous condenser
C)Tap changing transformer
D)Booster transformer

Accepted Answer

The answer of Which of the following equipment, for regulating...

Question 8

In a tap changing transformer, the tappings are provided on
A)primary winding
B)secondary winding
C)high voltage winding
D)any of the above

Accepted Answer

The answer of In a tap changing transformer, the tappings...

Question 9

Constant voltage transmission entails the following disadvantage
A)large conductor area is required for same power transmission
B)short-circuit current of the system is increased
C)either of the above
D)none of the above

Accepted Answer

The answer of Constant voltage transmission entails the following disadvantage
A)large...

Question 10

On which of the following factors skin effect depends ?
A)Frequency of the current
B)Size of the conductor
C)Resistivity of the conductor material
D)All of the above

Accepted Answer

Skin effect depends on the frequency of the current, the size of the conductor, and the resistivity of the conductor material. Higher frequencies, larger conductor sizes, and specific material resistivities can all influence the degree to which current is concentrated at the surface of a conductor, thus affecting the skin effect.

Question 11

The effect of corona can be detected by
A)presence of zone detected by odour
B)hissing sound
C)faint luminous glow of bluish colour
D)all of the above

Accepted Answer

Corona discharge can be detected by a combination of odor, sound, and visual indicators, including a faint bluish glow.

Question 12

For transmission of power over a distance of 500 km, the transmission voltage should be in the range
A)150 to 220 kV
B)100 to 120 kV
C)60 to 100 kV
D)20 to 50 kV

Accepted Answer

For transmission of power over long distances, such as 500 km, higher voltages are used to reduce power losses. The range of 150 to 220 kV is appropriate for such distances, as it helps in minimizing the line losses and improving efficiency. Lower voltage ranges would result in higher losses and are typically used for shorter distances or distribution networks rather than long-distance transmission.

Question 13

In the analysis of which of the following lines shunt capacitance is neglected ?
A)Short transmission lines
B)Medium transmission lines
C)Long transmission lines
D)Medium as well as long transmission lines

Accepted Answer

Shunt capacitance is neglected in the analysis of short transmission lines because their length is typically less than 80 kilometers, and the effects of capacitance are minimal compared to resistance and inductance over such short distances.

Question 14

When the interconnector between two stations has large reactance
A)the transfer of power will take place with voltage fluctuation and noise
B)the transfer of power will take place with least loss
C)the stations will fall out of step because of large angular displacement between the stations
D)none of the above

Accepted Answer

Large reactance in the interconnector can lead to a significant angular displacement between the stations, causing them to fall out of step.

Question 15

The frequency of voltage generated, in case of generators, can be increased by
A)using reactors
B)increasing the load
C)adjusting the governor
D)reducing the terminal voltage

Accepted Answer

The frequency of the voltage generated by a generator is primarily determined by the speed at which the generator's rotor is turning. Adjusting the governor, which controls the engine or turbine speed, can directly influence this speed, thereby increasing the frequency of the generated voltage. Reactors, load changes, and terminal voltage adjustments do not directly affect the generator's rotational speed and thus its frequency.

Question 16

When an alternator connected to the bus-bar is shut down the bus-bar voltage will
A)fall
B)rise
C)remain unchanged
D)none of the above

Accepted Answer

When an alternator is shut down, the bus-bar voltage typically remains unchanged because other alternators or sources connected to the bus-bar continue to maintain the voltage level.

Question 17

The angular displacement between two interconnected stations is mainly due to
A)armature reactance of both alternators
B)reactance of the interconnector
C)synchronous reactance of both the alternators
D)all of the above

Accepted Answer

The answer of The angular displacement between two interconnected stations...

Question 18

Electro-mechanical voltage regulators are generally used in
A)reactors
B)generators
C)transformers
D)all of the above

Accepted Answer

Electro-mechanical voltage regulators are primarily used in generators to maintain a constant voltage level. They adjust the voltage output of the generator by controlling the amount of current in the field winding.

Question 19

Series capacitors on transmission lines are of little use when the load VAR requirement is
A)large
B)small
C)fluctuating
D)any of the above

Accepted Answer

Series capacitors on transmission lines are primarily used to improve the voltage profile along the line by compensating for the inductive reactance of the line. They are of little use when the load VAR (Volt-Ampere Reactive) requirement is small because their main function is to manage larger reactive power demands to maintain system stability and efficiency.

Question 20

The voltage regulation in magnetic amplifier type voltage regulator is effected by
A)electromagnetic induction
B)varying the resistance
C)varying the reactance
D)variable transformer

Accepted Answer

Magnetic amplifiers control voltage by varying the reactance, which adjusts the impedance in the circuit to regulate the output voltage.

Quiz 4: Electrical Transmission and Insulation

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

The current drawn by the line due to corona losses is

Pin type insulators are generally not used for voltages beyond

Aluminium has a specific gravity of

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

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

Which of the following equipment, for regulating the voltage in distribution feeder, will be most economical ?

In a tap changing transformer, the tappings are provided on

Constant voltage transmission entails the following disadvantage

On which of the following factors skin effect depends ?

The effect of corona can be detected by

For transmission of power over a distance of 500 km, the transmission voltage should be in the range

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

When the interconnector between two stations has large reactance

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

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

The angular displacement between two interconnected stations is mainly due to

Electro-mechanical voltage regulators are generally used in

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

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