21. Which one of the following statement. is not correct for the use of bundled conductors in transmission lines?
(a) Control of voltage gradient
(b) Reduction in corona 1088
(c) Reduction in radio interference
(d) Increase in interference with communication lines
Ans: d
22. The main consideration for higher and higher operating voltage of transmission is to
(a) increase the efficiency of transmission
(b) reduce power losses
(c) increase power transmission capability
(d) both (a) and (b) above
Ans: c
23. A single phaae transmisson line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is
(a) unity
(b) 0.8 lagging
(c) 0.8 leading
(d) 0.6 lagging
Ans: d
24. A medium line with parameters A, B, C, D is extended by connecting a short line of impedance Z in series The overall ABCD parameteres of the series combinatton will be
(a) A, AZ, C + D/Z, D
(b) A, AZ + B, C, CZ + D
(c) A + BZ, B, C + DZ, D
(d) AZ, B, C/Z, D
Ans: b
25. When bundle conductors are used in place of single conductors, the effective inductance and capacitance will respectively
(a) increase and decrease
(b) decrease and increase
(c) decrease and remain unaffected
(d) remain unaffected and increase
Ans: c
26. To increase the visual critical voltage of cporona for an overhead line, one solid phase-conductor is replaced by a "bundle" of four smaller conductors per phase, having an aggregate cross-sectional area equal to that of the solid conductor. If the radius of the solid conductor is 40 mm, then the radius of each of the bundle conductors would be
(a) 10 mm
(b) 20 mm
(c) 28.2 mm
(d) 30 mm
Ans: d
27. For an existing ac transmision line, the string efficiency is 80%, if dc voltage is supplied for the same set up, the string efficiency will be
(a) < 80%
(b) 80%
(c) 90%
(d) 100%
Ans: b
28. In a string of suspension insulators, the voltage distribution across the different units of a string could be made uniform by the use of a grading ring, because it
(a) forms capacitances with link-pins to carry the charging current from link pins
(b) forms capacitances which help to cancel the charging current from link pins
(c) increases the capacitances of lower insulator units of cause equal voltage drop
(d) decreases the capacitances of upper insulators units to cause equal voltage drop
Ans: b
29. A three phase over head transmission line has its conductors horirzontally spaced with spacing between adjacent conductors equal to 'd'. if now the conductors of the line are rearranged to form and equilateral triangle of sides equal to 'd' then
(a) average capacitance and inductance will increase
(b) average capacitance will decrease and inductance will increase
(c) average capacitance will increase and inductance will decrease
(d) surge impedance loading of the line Increases
Ans: a
30. For a 500 Hz frequency excitation, a 50 km, long power line will be modelled as
(a) short line
(b) medium line
(c) long line
(d) data insufficiency for decision
Ans: c
Read More Questions:
Power Systems MCQs Part1
Power Systems MCQs Part2
(a) Control of voltage gradient
(b) Reduction in corona 1088
(c) Reduction in radio interference
(d) Increase in interference with communication lines
Ans: d
22. The main consideration for higher and higher operating voltage of transmission is to
(a) increase the efficiency of transmission
(b) reduce power losses
(c) increase power transmission capability
(d) both (a) and (b) above
Ans: c
23. A single phaae transmisson line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is
(a) unity
(b) 0.8 lagging
(c) 0.8 leading
(d) 0.6 lagging
Ans: d
24. A medium line with parameters A, B, C, D is extended by connecting a short line of impedance Z in series The overall ABCD parameteres of the series combinatton will be
(a) A, AZ, C + D/Z, D
(b) A, AZ + B, C, CZ + D
(c) A + BZ, B, C + DZ, D
(d) AZ, B, C/Z, D
Ans: b
25. When bundle conductors are used in place of single conductors, the effective inductance and capacitance will respectively
(a) increase and decrease
(b) decrease and increase
(c) decrease and remain unaffected
(d) remain unaffected and increase
Ans: c
26. To increase the visual critical voltage of cporona for an overhead line, one solid phase-conductor is replaced by a "bundle" of four smaller conductors per phase, having an aggregate cross-sectional area equal to that of the solid conductor. If the radius of the solid conductor is 40 mm, then the radius of each of the bundle conductors would be
(a) 10 mm
(b) 20 mm
(c) 28.2 mm
(d) 30 mm
Ans: d
27. For an existing ac transmision line, the string efficiency is 80%, if dc voltage is supplied for the same set up, the string efficiency will be
(a) < 80%
(b) 80%
(c) 90%
(d) 100%
Ans: b
28. In a string of suspension insulators, the voltage distribution across the different units of a string could be made uniform by the use of a grading ring, because it
(a) forms capacitances with link-pins to carry the charging current from link pins
(b) forms capacitances which help to cancel the charging current from link pins
(c) increases the capacitances of lower insulator units of cause equal voltage drop
(d) decreases the capacitances of upper insulators units to cause equal voltage drop
Ans: b
29. A three phase over head transmission line has its conductors horirzontally spaced with spacing between adjacent conductors equal to 'd'. if now the conductors of the line are rearranged to form and equilateral triangle of sides equal to 'd' then
(a) average capacitance and inductance will increase
(b) average capacitance will decrease and inductance will increase
(c) average capacitance will increase and inductance will decrease
(d) surge impedance loading of the line Increases
Ans: a
30. For a 500 Hz frequency excitation, a 50 km, long power line will be modelled as
(a) short line
(b) medium line
(c) long line
(d) data insufficiency for decision
Ans: c
Read More Questions:
Power Systems MCQs Part1
Power Systems MCQs Part2
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