Question 1

The heat produced at the contact point owing to flow of electric current is least affected by_____________________.

Accepted Answer

A) Temperature of the surrounding medium. 
B) Contact resistance. 
C) Magnitude of electric current flowing. 
D) Duration of flow of current. 
A) Temperature of the surrounding medium. 
B) Contact resistance. 
C) Magnitude of electric current flowing. 
D) Duration of flow of current. A

Question 2

The resistance of an electric arc can be increased by

Accepted Answer

A) Increasing the concentration of ionised particles. 
B) Reducing the arc length. 
C) Splitting the arc 
D) Increasing the arc cross section. 
A) Increasing the concentration of ionised particles. 
B) Reducing the arc length. 
C) Splitting the arc 
D) Increasing the arc cross section. C

Question 3

What is the advantage of HRC fuses over Rewirable fuses?

Accepted Answer

A) High speed operation 
B) High rupturing capacity 
C) No ageing effect. 
D) All of the above. 
A) High speed operation 
B) High rupturing capacity 
C) No ageing effect. 
D) All of the above. D

Question 4

Arcing voltage will be the least in case of

Accepted Answer

A) Carbon 
B) Copper 
C) Silver 
D) Tungsten 
A) Carbon 
B) Copper 
C) Silver 
D) Tungsten

Question 5

Which material is used in the liquid type of fuse?

Accepted Answer

A) SF6 
B) Distilled water 
C) Carbon tetra chloride. 
D) Mineral oil / transformer oil 
A) SF6 
B) Distilled water 
C) Carbon tetra chloride. 
D) Mineral oil / transformer oil

Question 6

Purpose of backup protection is

Accepted Answer

A) To increase the speed 
B) To increase a reach 
C) To leave no blind spot 
D) To guard against failure of primary 
A) To increase the speed 
B) To increase a reach 
C) To leave no blind spot 
D) To guard against failure of primary

Question 7

In a HRC fuse what is the time between the cut off and the final current zero called?

Accepted Answer

A) Pre - arcing time. 
B) Arcing time. 
C) Total operating time. 
D) None of these. 
A) Pre - arcing time. 
B) Arcing time. 
C) Total operating time. 
D) None of these.

Question 8

We do not require any protection against prime mover failure in case of

Accepted Answer

A) Turbo generator sets 
B) Hydro generator sets 
C) Diesel engine driven alternators 
D) Back pressure turbo generators 
A) Turbo generator sets 
B) Hydro generator sets 
C) Diesel engine driven alternators 
D) Back pressure turbo generators

Question 9

Outdoor switchgear is generally used for voltage beyond

Accepted Answer

A) 11 KV 
B) 33 KV 
C) 66 KV 
D) 132 KV 
A) 11 KV 
B) 33 KV 
C) 66 KV 
D) 132 KV

Question 10

The arc resistance depends on which among the following factors?

Accepted Answer

A) Cross section of the arc 
B) Length of the arc 
C) Degree of ionization 
D) All of the above. 
A) Cross section of the arc 
B) Length of the arc 
C) Degree of ionization 
D) All of the above.

Question 11

What is the typical value of the pre arcing time?

Accepted Answer

A) 0.1 
B) 0.01 
C) 0.001 
D) 0.0001 
A) 0.1 
B) 0.01 
C) 0.001 
D) 0.0001

Question 12

By using low resistance method for arc extension what is the value of arc resistance?

Accepted Answer

A) Arc resistance is zero. 
B) Arc resistance is high 
C) Arc resistance is low 
D) Arc resistance is very high 
A) Arc resistance is zero. 
B) Arc resistance is high 
C) Arc resistance is low 
D) Arc resistance is very high

Question 13

When a fault occurs in a high voltage transmission line, what happens first?

Accepted Answer

A) Circuit breaker operates then the relay. 
B) Relay operates and then the circuit breaker. 
C) Relay operates, then successively the isolator and the circuit breaker. 
D) Isolator operates, then successively the relay and the circuit breaker. 
A) Circuit breaker operates then the relay. 
B) Relay operates and then the circuit breaker. 
C) Relay operates, then successively the isolator and the circuit breaker. 
D) Isolator operates, then successively the relay and the circuit breaker.

Question 14

Upto what voltage a cartridge type of fuse can be used?

Accepted Answer

A) 400 V 
B) 11 kV 
C) 20 kV 
D) 33 kV 
A) 400 V 
B) 11 kV 
C) 20 kV 
D) 33 kV

Question 15

If the strands of the fusing wire are twisted, what happens to the fusing current?

Accepted Answer

A) Increases 
B) Reduces. 
C) No change/ remains same 
D) Depends on the value of current, increases or decreases. 
A) Increases 
B) Reduces. 
C) No change/ remains same 
D) Depends on the value of current, increases or decreases.

Question 16

How is the initiation of electric arc at the instant of contact separation caused?

Accepted Answer

A) Thermionic emission of electrons. 
B) Field emission of electrons. 
C) Both (a) and (b) 
D) None of these. 
A) Thermionic emission of electrons. 
B) Field emission of electrons. 
C) Both (a) and (b) 
D) None of these.

Question 17

The least expensive protection for over current in low-voltage system is

Accepted Answer

A) Rewirable fuse 
B) Isolator 
C) Circuit breaker 
D) Air-break switch 
A) Rewirable fuse 
B) Isolator 
C) Circuit breaker 
D) Air-break switch

Question 18

Upto what voltage can the liquid type HRC fuses be used?

Accepted Answer

A) 33 kV 
B) 132 kV 
C) 66 kV 
D) 220 kV 
A) 33 kV 
B) 132 kV 
C) 66 kV 
D) 220 kV

Question 19

What is the arc voltage in a circuit breaker?

Accepted Answer

A) In phase with the arc current. 
B) Lagging the arc current by 90° 
C) Leading the arc current by 90° 
D) Lagging the arcing current by 180° 
A) In phase with the arc current. 
B) Lagging the arc current by 90° 
C) Leading the arc current by 90° 
D) Lagging the arcing current by 180°

Question 20

What happens in the arc extinction using high resistance method?

Accepted Answer

A) Arc resistance is decreased with time. 
B) Arc resistance is increased with time. 
C) No change it remains same. 
D) Arc resistance is kept zero. 
A) Arc resistance is decreased with time. 
B) Arc resistance is increased with time. 
C) No change it remains same. 
D) Arc resistance is kept zero.

The heat produced at the contact point owing to flow of electric current is least affected by_____________________.

The resistance of an electric arc can be increased by

What is the advantage of HRC fuses over Rewirable fuses?

Arcing voltage will be the least in case of

Which material is used in the liquid type of fuse?

Purpose of backup protection is

In a HRC fuse what is the time between the cut off and the final current zero called?

We do not require any protection against prime mover failure in case of

Outdoor switchgear is generally used for voltage beyond

The arc resistance depends on which among the following factors?

What is the typical value of the pre arcing time?

By using low resistance method for arc extension what is the value of arc resistance?

When a fault occurs in a high voltage transmission line, what happens first?

Upto what voltage a cartridge type of fuse can be used?

If the strands of the fusing wire are twisted, what happens to the fusing current?

How is the initiation of electric arc at the instant of contact separation caused?

The least expensive protection for over current in low-voltage system is

Upto what voltage can the liquid type HRC fuses be used?

What is the arc voltage in a circuit breaker?

What happens in the arc extinction using high resistance method?

Electrical Protection and Circuit Breakers

Electrical Protection and Transmission Line Characteristics

Power System Protection and Equipment

Electrical Protection and Safety: Part A

Electrical Protection and Safety: Part B

Protective Relays and Circuit Breakers for Electrical Systems

Circuit Breakers and Fuses

Electrical Components and Circuit Breakers

Electrical Protection and Switchgear

Relaying Schemes and Techniques for Electrical Equipment Protection

Understanding Relays for Power System Protection

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Exam 8: Electric Arc and Circuit Breaker Protection

The heat produced at the contact point owing to flow of electric current is least affected by_____________________.

The resistance of an electric arc can be increased by

What is the advantage of HRC fuses over Rewirable fuses?

Arcing voltage will be the least in case of

Which material is used in the liquid type of fuse?

Purpose of backup protection is

In a HRC fuse what is the time between the cut off and the final current zero called?

We do not require any protection against prime mover failure in case of

Outdoor switchgear is generally used for voltage beyond

The arc resistance depends on which among the following factors?

What is the typical value of the pre arcing time?

By using low resistance method for arc extension what is the value of arc resistance?

When a fault occurs in a high voltage transmission line, what happens first?

Upto what voltage a cartridge type of fuse can be used?

If the strands of the fusing wire are twisted, what happens to the fusing current?

How is the initiation of electric arc at the instant of contact separation caused?

The least expensive protection for over current in low-voltage system is

Upto what voltage can the liquid type HRC fuses be used?

What is the arc voltage in a circuit breaker?

What happens in the arc extinction using high resistance method?

Electrical Protection and Circuit Breakers

Electrical Protection and Transmission Line Characteristics

Power System Protection and Equipment

Electrical Protection and Safety: Part A

Electrical Protection and Safety: Part B

Protective Relays and Circuit Breakers for Electrical Systems

Circuit Breakers and Fuses

Electrical Components and Circuit Breakers

Electrical Protection and Switchgear

Relaying Schemes and Techniques for Electrical Equipment Protection

Understanding Relays for Power System Protection

Filters