Questions
3
The dielectric strength of air under normal conditions is around
Answer: 30 kV/cm
5
Critical voltage limit of a transmission line is increased by
Answer: Increasing the radius of the conductors
7
The inductance of line is minimum when
Answer: G M D is low but G M R is high
8
The inductance of single phase two wire power transmission line per km gets doubled when the
Answer: Distance between the wires is increased as square of the original distance
9
Compared with solid conductor of the same radius, corona appears on a stranded conductor at a lower voltage, because stranding
Answer: produces surfaces of smaller radius
10
High voltage transmission lines are transposed because then
Answer: Phase voltage imbalances can be minimized
11
Transposition of transmission line is done to
Answer: Balance line voltage drop
12
Increase in frequency of transmission line causes
Answer: Increases in line resistance
13
The presence of earth in case of overhead lines
Answer: Increases the capacitance
15
In a transmission line the distributed constants are
Answer: Resistance, inductance, capacitance and shunt conductance.
16
The presence of earth in case of overhead lines
Answer: Increases the capacitance
17
Which of the following is neglected while analyzing a short transmission line?
Answer: Shunt admittances
18
Following effects are associated with transmission lines
1. Skin effect
2. Corona effect
3. Proximity effect
The effective resistance of conductor is increased by
Answer: 1 and 3 only
19
For 11 kV transmission line the capacitance per km will be about
Answer: 0.01 F.
20
Percentage regulation of transmission line is given by the expression
Answer: (VS - VR)/VR × 100
