Question 1

Which of the following is not a part of the circuit breaker?

Accepted Answer

A) Explosion pot 
B) Fixed and moving contacts 
C) Conservator 
D) Operating mechanism. 
A) Explosion pot 
B) Fixed and moving contacts 
C) Conservator 
D) Operating mechanism. C

Question 2

Which of the following statement about SF6 gas is incorrect?

Accepted Answer

A) It is non-toxic gas 
B) It is non-inflammable 
C) It has density 5 times that of air at 200C 
D) It has dark yellow color. 
A) It is non-toxic gas 
B) It is non-inflammable 
C) It has density 5 times that of air at 200C 
D) It has dark yellow color. D

Question 3

The breaking capacity of a circuit breaker in MVA (3 phase) is given by

Accepted Answer

A) Rated service voltage x rated symmetrical current 
B) 1.1 x rated service voltage x rated symmetrical current 
C) (2)1/2 x rated service voltage x rated symmetrical current 
D) (3)1/2x rated service voltage x rated symmetrical current. 
A) Rated service voltage x rated symmetrical current 
B) 1.1 x rated service voltage x rated symmetrical current 
C) (2)1/2 x rated service voltage x rated symmetrical current 
D) (3)1/2x rated service voltage x rated symmetrical current. D

Question 4

For a circuit breaker 'break time' is

Accepted Answer

A) Same as opening time 
B) Opening time + arc duration 
C) Opening time + arc duration + resistor current duration. 
D) none 
A) Same as opening time 
B) Opening time + arc duration 
C) Opening time + arc duration + resistor current duration. 
D) none

Question 5

Which of the following relays is used on transformers?

Accepted Answer

A) Buchholz relay 
B) MHO relay 
C) Merz price relay 
D) None of the above. 
A) Buchholz relay 
B) MHO relay 
C) Merz price relay 
D) None of the above.

Question 6

Which of the following is the demerit of SF6 circuit breakers?

Accepted Answer

A) Sealing problem of gas 
B) In flux of moisture in the gas system is dangerous 
C) Deterioration of quality of circuit breaker affects reliability of circuit breaker 
D) All of the above. 
A) Sealing problem of gas 
B) In flux of moisture in the gas system is dangerous 
C) Deterioration of quality of circuit breaker affects reliability of circuit breaker 
D) All of the above.

Question 7

The values of fault current depend on

Accepted Answer

A) Voltage at the faulty point 
B) Total impedance up to the fault 
C) Both (
A)  and (
B)  above 
D) None of the above 
A) Voltage at the faulty point 
B) Total impedance up to the fault 
C) Both (
A)  and (
B)  above 
D) None of the above

Question 8

Merz-price protection is used on

Accepted Answer

A) Substations 
B) Capacitor bank 
C) Induction motor 
D) Generators. 
A) Substations 
B) Capacitor bank 
C) Induction motor 
D) Generators.

Question 9

The tripping circuit is_

Accepted Answer

A) AC 
B) DC 
C) either AC or DC 
D) None of these 
A) AC 
B) DC 
C) either AC or DC 
D) None of these

Question 10

Plug setting of a electromagnetic relay can be altered by varying

Accepted Answer

A) Number of ampere turns 
B) Air gap of magnetic path 
C) Adjustable back stop 
D) None of these 
A) Number of ampere turns 
B) Air gap of magnetic path 
C) Adjustable back stop 
D) None of these

Question 11

Which of the following are air-break switching devices ?

Accepted Answer

A) Isolator 
B) Limit switch 
C) Earthling switch 
D) All of the above. 
A) Isolator 
B) Limit switch 
C) Earthling switch 
D) All of the above.

Question 12

The protection against over-voltage due to lightening is provided by

Accepted Answer

A) Use of surge diverters 
B) Low tower footing resistance 
C) Use of overhead ground wires 
D) Any of the above. 
A) Use of surge diverters 
B) Low tower footing resistance 
C) Use of overhead ground wires 
D) Any of the above.

Question 13

Which of the following is a conducting medium for electric current ?

Accepted Answer

A) Low temperature gas 
B) High temperature gas 
C) Dissociated gas 
D) Plasma. 
A) Low temperature gas 
B) High temperature gas 
C) Dissociated gas 
D) Plasma.

Question 14

Which relay is used for feeders?

Accepted Answer

A) MHO relay 
B) Translay relay 
C) Merz price protection 
D) Buchholz relay. 
A) MHO relay 
B) Translay relay 
C) Merz price protection 
D) Buchholz relay.

Question 15

the most efficient torque producing actuating structure for the induction type relays is

Accepted Answer

A) Shaded pole structure 
B) Watt hour meter structure 
C) Induction cup structure 
D) Single induction loop structure 
A) Shaded pole structure 
B) Watt hour meter structure 
C) Induction cup structure 
D) Single induction loop structure

Question 16

MHO relay is used for

Accepted Answer

A) Rectifiers 
B) Circuit breakers 
C) Transmission lines 
D) Feeders. 
A) Rectifiers 
B) Circuit breakers 
C) Transmission lines 
D) Feeders.

Question 17

The over-voltage surges in power systems may be caused by

Accepted Answer

A) Lightning 
B) Switching 
C) Resonance 
D) Any of the above. 
A) Lightning 
B) Switching 
C) Resonance 
D) Any of the above.

Question 18

Which of the following circuit breaker will produce the least arc energy?

Accepted Answer

A) Minimum oil circuit breaker 
B) Air blast circuit breaker 
C) Plain oil circuit breaker 
D) All will produce same energy. 
A) Minimum oil circuit breaker 
B) Air blast circuit breaker 
C) Plain oil circuit breaker 
D) All will produce same energy.

Question 19

Dielectric strength of SF6 is

Accepted Answer

A) less than that of air at atmospheric pressure 
B) less than that of oil used in OCB 
C) more than that of oil used in OCB 
D) More at lower pressure and low at higher pressures. 
A) less than that of air at atmospheric pressure 
B) less than that of oil used in OCB 
C) more than that of oil used in OCB 
D) More at lower pressure and low at higher pressures.

Question 20

Which component ensures the safety of the line from damage?

Accepted Answer

A) Relay 
B) Circuit breaker 
C) Bus bar 
D) Current tr 
A) Relay 
B) Circuit breaker 
C) Bus bar 
D) Current tr

Which of the following is not a part of the circuit breaker?

Which of the following statement about SF6 gas is incorrect?

The breaking capacity of a circuit breaker in MVA (3 phase) is given by

For a circuit breaker 'break time' is

Which of the following relays is used on transformers?

Which of the following is the demerit of SF6 circuit breakers?

The values of fault current depend on

Merz-price protection is used on

The tripping circuit is_

Plug setting of a electromagnetic relay can be altered by varying

Which of the following are air-break switching devices ?

The protection against over-voltage due to lightening is provided by

Which of the following is a conducting medium for electric current ?

Which relay is used for feeders?

the most efficient torque producing actuating structure for the induction type relays is

MHO relay is used for

The over-voltage surges in power systems may be caused by

Which of the following circuit breaker will produce the least arc energy?

Dielectric strength of SF6 is

Which component ensures the safety of the line from damage?

Electrical Components and Protective Relays

Electrical Protection and Transmission Systems

Electrical Substation Equipment and Protection Systems

Electrical Protection and Circuit Breakers

Electrical Protection and Switchgear Systems

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Exam 6: Electrical Protection and Circuit Breakers

Which of the following is not a part of the circuit breaker?

Which of the following statement about SF6 gas is incorrect?

The breaking capacity of a circuit breaker in MVA (3 phase) is given by

For a circuit breaker 'break time' is

Which of the following relays is used on transformers?

Which of the following is the demerit of SF6 circuit breakers?

The values of fault current depend on

Merz-price protection is used on

The tripping circuit is_

Plug setting of a electromagnetic relay can be altered by varying

Which of the following are air-break switching devices ?

The protection against over-voltage due to lightening is provided by

Which of the following is a conducting medium for electric current ?

Which relay is used for feeders?

the most efficient torque producing actuating structure for the induction type relays is

MHO relay is used for

The over-voltage surges in power systems may be caused by

Which of the following circuit breaker will produce the least arc energy?

Dielectric strength of SF6 is

Which component ensures the safety of the line from damage?

Electrical Components and Protective Relays

Electrical Protection and Transmission Systems

Electrical Substation Equipment and Protection Systems

Electrical Protection and Circuit Breakers

Electrical Protection and Switchgear Systems

Filters