WorksheetsT&D Quiz Unit 1
Total questions: 30
Worksheet time: 32mins
The surge impedance of 50 miles long underground cable is 50 ohms. For a 25 mile length, it will be
25 ohms
50 ohms
100 ohms
None of the above
The self GMD method is used to evaluate
Inductance
Capacitance
Inductance and capacitance both
None of the above
The inductance of a single phase 2 wire transmission line per km gets doubled when
the distance between the wires is doubled
distance between the wires is increased four fold
distance between the wires is increased as square of the original distance
radius of the wire is doubled
Transmission lines are transposed to
reduce copper loss
reduce skin effect
prevent interference with neighbouring telephone lines
prevent short circuit between any two lines
A single phase transmission line of impedance j0.8 ohm supplies a resistive load of 500A at 300V. The sending end power factor is
unity
0.8 lag
0.8 lead
0.6 lag
Bundled conductors in transmission line provide
reduced capacitance
increased capacitance
increased inductance
increased voltage gradient
When bundle conductors are used in place of single conductors, the effective inductance and capacitance will respectively
increase and decrease
decrease and increase
decrease and remains unaffected
remains unaffected and increase
The inductance of a three phase transmission line is 1.2mH/ph/km.If the spacing of conductors and the radius of the conductor are doubled, then the inductance of the line will be
4.8mH/ph/km
1.2 mH/ph/km
(Logn2)*1.2mH/ph/km
(Logn4)*1.2mH/ph/km
Which one of the following statements is not true for the use of bundled conductors in transmission lines
Control of voltage gradient
Reduction in corona loss
Reduction in inductance
Increase in interference with communication lines
A three phase transmission line has conductors arranged in horizontal spacing with 'd' as the distance between the conductors. If these conductors are rearranged to form an equilateral triangle with sides equal 'd', then the
Capacitance and Inductance will increase
Capacitance will increase and inductance will decrease
Capacitance and inductance will remain the same
Capacitance will decrease and inductance will increase
The inductance per unit length of an overhead line due to internal flux linkages
depends on the size of the conductor
is constant and independent of the size of the conductor
depends on the current through the conductor
depends on distance between conductors
Which of the following is not a component of a distribution system?
Substation
Feeder
Generator
Service mains
Which of the following is not an advantage of a dc system?
Voltage regulation
Stability
Interference with communication circuits
Circuit breaking
Which of the following parameter is not an advantage of high voltage transmission?
Line losses
Voltage regulation
Corona
Power handling capacity
Which of the following is not a transmission line device parameter?
Conductance
Regulation
Resistance
Capacitance
Which of the following is not a requirement of transmission line conductors?
Insulation
Conductivity
Weight
Tensile strength
Which of the following attribute is not an advantage for Aluminium conductors over copper?
Tensile strength
Cost
Corona
Weight
Which conductor is predominantly used in transmission lines in India?
All aluminium
Aluminium with steel reinforcement
Hard drawn copper
Cadmium copper
Transmission line efficiency primarily depends on
Line resistance
Line inductance
Line capacitance
None of the above
When the area of cross section of a conductor is doubled, the resistance of the conductor is
doubled
halved
remains same
none of the above
With increasing temperature, the resistance of a conductor
increases
decreases
remains same
none of the above
Effective radius of a conductor 'r' considering internal flux linkages is
0.6718 times 'r'
0.7788 times 'r'
0.7877 times 'r'
None of the above
Skin effect does not depend on
Material of the conductor
Frequency of supply
Distance between phase conductors
Diameter of conductor
Which of the following is not a feature of double circuit lines?
Continuity of supply
Lesser spacing between conductors
Higher inductive reactance
Deeper foundation
When the spacing between phase condcutors is increased,
Capacitance of the conductor remains same
Capacitance of the conductor increases
Capacitance of the conductor decreases
None of the above
Due to the effect of earth, the capacitance of the conductor
Slightly Increases
Slightly decreases
Remains same
None of the above
When frequency of supply increases, the charging current
Increases
Decreases
Remains same
None of the above
Proximity effect does not depend on
Frequency
Resistivity of conductor material
Diameter of conductor
Tower height
With increasing frequency, skin effect
Increases
Decreases
Remains same
None of the above
A 3 phase transmission line has its conductors at the corners of an equilateral triangle with side 3m. The diameter of each conductor is 1.63cm. Find the inductance per km per phase of the line.
0.78 mH/km
1.23 mH/km
0.48H/km
None of the above
