EXTRA HIGH VOLTAGE POWER TRANSMISSION UNIT III VOLTAGE GRADIENTS ON CONDUCTORS 2 MARKS QUESTION & ANSWERS

EXTRA HIGH VOLTAGE POWER TRANSMISSION

UNIT III

VOLTAGE GRADIENTS ON CONDUCTORS

2       MARKS QUESTION & ANSWERS

1.     What is meant by voltage gradient?

A voltage per unit length along a resistor or other conductive paths, or it’s the change in the electric potential measure between earth  point of high potential to low potential.

2.     State the equivalent radius or geometric mean radius of a bundled conductor?

The equivalent radius or geometric mean radius of a bundled conductor is

                            

R = bundle radius,

r = radius of each sub-conductor,

N = number of conductors in the bundle.

3.     State the charge potential relation for multi conductors’ lines?

The effect of a ground plane considered as an equipotential surface gave rise to Maxwell's Potential coefficients and the general equations are

                                            

4.     Define the Maximum Charge Condition on a 3-Phase Line?

E.H.V. transmission lines are mostly single-circuit lines on a tower with one or two ground wires. The equation for maximum charge is

5.     Draw the diagram for distribution of gradient on 2 bundle conductor?

6.     Draw the average height over a span S with sag d?

7.     State the average inductance over the span?

The average inductance over the span is

8.     Calculate   for  H = 10, d = 10?

                      = 10 + (10/3)

                      = 13.3

9.     Calculate    for  H=10, d=8?

          

                      = 10 + (8/3)

                      = 12.25

10.             Calculate   for H= 14, d=10?

                       = 14 + (10/3)

                      = 17.3

11.            Draw the diagram for 2 conductor bundle above ground for voltage gradient calculation?

            

12.What are the assumptions of  2 conductor bundle?

1. The conductors of the other phases or poles are very far from the bundled conductor under examination, i.e

2. The image conductors are also very far, i.e. .

13. State the formula of    of 2 conductors bundle?

                            

14.State the formula of    of 2 conductors bundle?

                            

15. Define Maximum Surface Voltage Gradients for?

The maximum surface voltage gradients for number of sub conductor more or equal to three will be

                   

16. What is meant by Markt-Mengele Formula?

A 3-phase ac line with horizontal configuration of phases, a convenient formula due to Mangoldt can be derived. This is known as the Markt-Mengele Formula.

17. State the formula of ?

             

18. State the formula of ?

               

19.State the formula of for bipolar DC line?

             

20. State the formula of gradient factor?

                   The gradient factor is denoted as