Power System Protection MCQ
Power System Protection is focused on the implementation of schemes and procedures for protecting electrical power systems against faults.
Electrical Engineering MCQ
The most dangerous fault
The most dangerous fault:
- 3 phase fault
- Line to line fault
- Line to ground gault
- Double line to ground fault
Correct answer: 1. 3 phase fault
Heavy current fuses have wires that are in diameter than smaller ones
Heavy current fuses have wires that are _________ in diameter than smaller ones:
- Larger
- Smaller
- Same
- Any of above
Correct answer: 1. Larger
The pickup current of a relay having 125% current setting connected to 100/5 transformer is
The pickup current of a relay having 125% current setting connected to 100/5 transformer is:
- 1 Amp
- 5 Amp
- 6.25 Amp
- 10 Amp
Correct answer: 3. 6.25 Amp
Which device signals the circuit breaker in case of fault
______________ signals circuit breaker in case of fault:
- Fuse
- Isolator
- CT
- Relay
Correct answer: 4. Relay
Buchholz relay is used for protection of
Buchholz relay is used for protection of:
- Busbar
- Transformer
- Alternator
- Motors
Correct answer: 2. Transformer
While short-circuit test on circuit breaker a protection engineer obtained following readings on single frequency transient
While short-circuit test on circuit breaker a protection engineer obtained following readings on single frequency transient:
Time to reach the peak re-striking voltage = 50 µsec
Peak re-striking voltage = 150 kV
The average RRRV is:
- 2.5 kV/µsec
- 5 kV/µsec
- 10 kV/µsec
- 50 kV/µsec
Correct answer: 5 kV/µsec
Formula Hint: Average RRRV = Peak restriking voltage/Time to reach peak value
What is the approximate value of the contact resistance of circuit breaker
What is approximate value of the contact resistance of circuit breaker:
- 25 µΩ
- 25 mΩ
- 25 Ω
- 250 Ω
Correct answer: 1. 25 µΩ
Important Note: Contact resistance test of circuit breaker may not be the sole predictor of breaker thermal performance.
Which of the following voltage surge is more harmful: 1/50 µs or 4/50 µs
Which of the following voltage surge is more harmful: 1/50 µs or 4/50 µs:
- 1/50 µs is more harmful
- 4/50 µs is more harmful
- Both are equally armful
- Insufficient data provided
Correct answer: 1. 1/50 µs is more harmful
Explanation: A 1/50 µs reaches to its maximum value in 1 µs while it decays to half of its peak value in 50 µs. While a 4/50 µs surge will reach to the maximum value in 4 µs while decays to half of its peak value in 50 µs.
More MCQ Questions
- Power System Protection MCQ Part 1
- Power System Protection MCQ Part 2
- Power System Protection MCQ Part 3
- Power System Protection MCQ Part 4
- Power System Protection MCQ Part 5
- Power System Protection MCQ Part 6
- Power System Protection MCQ Part 7
- Power System Protection MCQ Part 8
- Power System Protection MCQ Part 9
- Power System Protection MCQ Part 10
More MCQ on Power System Protection:
- Breaking capacity is the value
- Lubrication oil failure results in
- Which one of the following is classified as an electrical fault
- The most common cause of motor damage is
- Active fault refers to
- The term Passive faults in Power system refers to
- Incipient faults are best defined as faults that
- The more accurately the fault is detected by the protection system, the more is it
- The smaller the current a protection system detects, the more the is it
- Which type of fault has the highest probability of occurrence on the power system
- The Zero-sequence current can flow from a line to the transformer bank if the windings are in