Power System Protection MCQs Part 10
a. Statement: Differential protection scheme should not be employed for longer transmission lines.
Logic: It is very expensive.
- Both statement and logic are wrong
- The statement is correct, but logic is incorrect
- The statement is incorrect, but logic is correct
- Logic defends the statement
Correct answer: 4. Logic defends the statement
b. The instantaneous relays used for earth fault detection in motors is usually set to _____________:
- 50% of the RLA
- 50% of the FLA
- 20% of the RLA
- 20% of the FLA
Correct answer: 4. 20% of the FLA
c. Declaration: Ground wires can easily protect the equipment from direct lightning thunders.
X: Ground wires are used to provide protection against traveling waves
- X is an application of declaration
- Both declaration and X are incorrect
- The declaration is correct, X is incorrect
- Declaration and X explain the same fact in different words
Correct answer: 3. The declaration is correct, X is incorrect
d. The method in which earthing is done through a transformer is referred as:
- Effective earthing
- Non-effective earthing
- Peterson coil earthing
- Flick method
Correct answer: 2. Non-effective earthing
e. The term non-effective earthing refers to the earthing which is done through:
- Resistance
- Reactance
- Transformer
- All of these
Correct answer: 4. All of these
f. Argument: Resistance earthing can’t be used for single phase loads.
Solution: Households always employ solid earthing.
- Argument and solution are not connected in the present context
- Argument leads to the solution
- The argument is wrong, the solution is correct
- Both solution and argument are wrong
Correct answer: 2. Argument leads to a solution
Explanation: The resistance earthing can’t be used for single phase loads due to which the solid earthing method is used by households.
g. Striker pin fuse is used for:
- LV circuits
- LV and MV circuits
- MV and HV circuits
- HV circuits
Correct answer: 2. LV and MV circuits
h. R.R.R.V depends on the:
- Inductance
- Capacitance
- Both of these
- None of these
Correct answer: 3. Both of these
i. The arc voltage is always _______________ the current:
- Leading
- Lagging
- In phase with
Correct answer: 3. In phase with
j. If the time required to reach the peak value is 100 µsec and the peak re-striking voltage is 200 kV, then average RRRV is:
- 20 MV/µsec
- 2 kV/µsec
- 200 MV/µsec
- 20 kV/µsec
Correct answer: 2. 2 kV/µsec
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