Power System Protection MCQs - Quiz 1

1. Insulation resistance of HV circuit breakers is more than ___ mega ohms.
A) 1
B) 10
C) 100
D) 1000

The correct answer is C

2. Which of the following is the least expensive overcurrent protection for LV system?
A) Isolator
B) Rewireable fuse
C) Oil circuit breaker
D) None of the above

The correct answer is B

3. The contacts of high voltage breakers used in power system are submerged in oil to:
A) Extinguish the arc
B) Insulate the contacts from switch body
C) Lubricate the contacts
D) None of the above

The correct answer is A

4. To protect most of the electrical equipment handling low power, the types of relays used are:
A) Thermocouple
B) Electronic and bimetallic
C) Both A & B
D) None of the above

The correct answer is C

5. The co-efficient of reflection at the open circuited end of a transmission line is:
A) Zero
B) Unity
C) Infinity
D) None of the above

The correct answer is B

6. A ___ is used to measure the stator winding temperature in a generator.
A) Resistance thermometer
B) Pyrometer
C) Thermocouple
D) Thermometer

The correct answer is A

7. The under voltage relay can be used for:
A) Generators
B) Busbars
C) Transformers
D) All of the above

The correct answer is D

8. Which of these devices will receive voltage surge first travelling on the transmission line?
A) Relays
B) Lightning arresters
C) Step down transformer
D) Switchgear

The correct answer is B

9. Which of the following parameters can be neglected for a short line?
A) Resistance
B) Capacitance
C) Inductance
D) Reactance

The correct answer is B

10. The relay with inverse time characteristic will operate within ___ sec.
A) 20 to 30
B) 5 to 20
C) 5 to 10
D) None of the above

The correct answer is C