Electrical Power Transmission MCQs Part 16
Contents
- 1 Potential across the various discs of suspension string is different. This is primarily due to
- 2 If safety factor is doubled, sag of line will
- 3 Shunt capacitance in string of suspension insulators can be decreased using
- 4 If spacing between conductors increases, the corona effect
- 5 Power loss in an overhead transmission line mainly occurs due to
Potential across the various discs of suspension string is different. This is primarily due to
Potential across the various discs of suspension string is different. This is primarily due to:
- Self-capacitance
- Shunt capacitance
- Both of these
- None of these
Correct answer: 2. Shunt capacitance
Also see: String efficiency formula
If safety factor is doubled, sag of line will
If safety factor is doubled, sag of line will:
- Increase
- Decrease
- Remain unchanged
- None of the above
Correct answer: 1. Increase
Explanation:
The formula for allowable tension (T) is: T = Ultimate strength/Safety factor
While Sag has the formula: S = (wl²)/8T = {(wl²)/8 } * {Safety Factor/Ultimate strength}
Since both are directly related to each other, doubling safety factor increases sag
Shunt capacitance in string of suspension insulators can be decreased using
Shunt capacitance in string of suspension insulators can be decreased using:
- Shorter cross-arms
- Longer cross-arms
- Longer spans
- None of these
Correct answer: 2. Longer cross-arms
Explanation: In order to reduce shunt capacitance, distance of conductor from tower must be increased. In other terms/words, the longer cross-arms should be used.
Also see practical applications of Suspension type insulators
If spacing between conductors increases, the corona effect
If spacing between conductors increases, the corona effect:
- Increases
- Decreases
- Remains unchanged
- None of these
Correct answer: 2. Decreases
Explanation: If spacing between conductors is large compared to their diameters, the electrostatic stress at conductor surface is decreases. As a result of this the corona effect decreases.
Power loss in an overhead transmission line mainly occurs due to
Power loss in an overhead transmission line mainly occurs due to:
- Resistance of the line
- Capacitance of the line
- Inductance of the line
- None of these
Correct answer: 1. Resistance of the line
Explanation: The line resistance is the major factor that is responsible for power loss in an overhead transmission line.
See complete list of Electric Power Transmission MCQs