Power System Protection MCQs Part 7
a. The selectivity of the system is increased by:
- Considering the system as a single block
- Dividing the system into various protection zones
- Dividing system into two large blocks
- None of these
Correct answer: 2. Dividing the system into various protection zones
b. The protection system which compares the electrical quantity which enters and leaves any zone and then operates is:
- Balanced voltage
- Balanced current
- Differential protection system
- All of these
Correct answer: 4. All of these
c. Solkor unit protection is used with ________________:
- Stranded nonmetallic buses
- Solid metallic pilot wires
- Induction motors
- Transformers
Correct answer: 2. Solid metallic pilot wires
d. For safe operations, the transformer oil should have a minimum dielectric strength of:
- 10 KV
- 20 kV
- 50 kV
- 100 KV
Correct answer: 3. 50 kV
e. The protection relay which has inherent directional characteristics:
- Mho relay
- Reactance relay
- Distance relay
- All of these
Correct answer: 1. Mho relay
f. The magnetic circuit breaker has:
- Instantaneous working action
- Delays working action
- Both of these
- None of these
Correct answer: 1. Instantaneous working action
g. The correct statement about the unbalanced condition in alternator:
- The same current flows through different phases in the unbalanced alternator
- Unbalanced loading is not dangerous for the alternator
- Unbalanced loading introduces eddy current in the alternator
- None of these is correct
Correct answer: 3. Unbalanced loading introduces eddy current in the alternator
h. The circuit breaker which produces least arc energy:
- Air Blast
- Air break
- Bulk oil
- Plain oil
Correct answer: 1. Air Blast
i. The correct statement about Buchholz relay
- It can only be used with largely sized alternators
- It is installed with largely sized transformers which have no conservator tank
- It can detect incipient faults
- It should never be used with oil immersed transformers
Correct answer: 3. It can detect incipient faults
j. Generally, earth relays have _____________ current setting:
- Lower
- Higher
Correct answer: 1. Lower
Continue reading:
- Power System Protection MCQs Part 1
- Power System Protection MCQs Part 2
- Power System Protection MCQs Part 3
- Power System Protection MCQs Part 4
- Power System Protection MCQs Part 5
- Power System Protection MCQs Part 6
- Power System Protection MCQs Part 7
- Power System Protection MCQs Part 8
- Power System Protection MCQs Part 9
- Power System Protection MCQs Part 10