Power System - I (3140914) MCQs

MCQs of Mechanical Features and Design of Overhead Transmission Line

Showing 91 to 100 out of 108 Questions
6 7 8 9 10 11
91.
A suspension type insulator has three units with self-capacitance C and ground capacitance of 0.2C having a string efficiency of
(a) 78%
(b) 80%
(c) 82%
(d) 84%
Answer:

Option (a)

92.
Stringing chart is useful for
(a) Finding the sag in the conductor
(b) In the design of tower
(c) In the design of insulator string
(d) Finding the distance between the tower
Answer:

Option (a)

93.
For an existing AC transmission line the string efficiency is 80%. Now if DC voltage is supplied for the same set up, the string efficiency will be
(a) 80%
(b) More than 80%
(c) Less than 80%
(d) 100%
Answer:

Option (d)

94.
Effect of increase in temperature in overhead transmission lines is to
(a) Increase the stress and length
(b) Decrease the stress and length
(c) Decrease the stress but increase the length
(d) None of the above
Answer:

Option (c)

95.
A 66 kV system has string insulator having five discs and the earth to disc capacitance ratio of 0.10. The string efficiency will be
(a) 89%
(b) 75%
(c) 67%
(d) 55%
Answer:

Option (c)

96.
The voltages across the various discs of a string of suspension insulators having identical discs is different due to
(a) Surface leakage currents
(b) Series capacitance
(c) Shunt capacitance to ground
(d) Series and shunt capacitance
Answer:

Option (c)

97.
The non-uniform distribution of voltage across the units in a string of suspension type insulators is due to
(a) Unequal self-capacitance of the units
(b) Non-uniform distance of separation of the units from the tower body
(c) The existence of stray capacitance between the metallic junctions of the units and the tower body
(d) Non-uniform distance between the cross-arm and the units
Answer:

Option (c)

98.
Whenever the conductors are dead-ended or there is a change in the direction of transmission line, the insulators used are of the
(a) Pin type
(b) Suspension type
(c) Strain type
(d) Shackle type
Answer:

Option (c)

99.
Consider the following statements: In the case of suspension type insulators, the string efficiency can be improved by
1. Using a longer cross arm
2. Using a guard ring
3. Grading the insulator discs
4. Reducing the cross arm length
(a) 1 and 3 are correct
(b) 1, 2 and 3 are correct
(c) 2, 3 and 4 are correct
(d) 2 and 4 are correct
Answer:

Option (b)

100.
Expanded ACSR are conductor composed of
(a) Larger diameter individual strands for a given cross-section of the aluminum strands
(b) Larger diameter of the central steel strands for a given overall diameter of the conductor
(c) Larger diameter of the aluminum strand only for a given overall diameter of the conductor
(d) A filler between the inner steel and the outer aluminum strands to increase the overall diameter of the conductor
Answer:

Option (d)

Showing 91 to 100 out of 108 Questions
6 7 8 9 10 11