Important Questions of Electrical Design of Overhead Lines:

1. What do you understand by the constants of an overhead transmission line ?

2. What is skin effect ? Why is it absent in the d.c. system ?

3. Find an expression for the flux linkages

(i) due to a single current carrying conductor

(ii) in parallel current carrying conductors

4. Derive an expression for the loop inductance of a single phase line.

5. Derive an expression for the inductance per phase for a 3-phase overhead transmission line when

(i) conductors are symmetrically placed

(ii) conductors are unsymmetrically placed but the line is completely transposed

6. What do you understand by electric potential ? Derive an expression for electric potential

(i) at a charged single conductor

(ii) at a conductor in a group of charged conductors

7. Derive an expression for the capacitance of a single phase overhead transmission line.

8. Deduce an expression for line to neutral capacitance for a 3-phase overhead transmission line when the conductors are

(i) symmetrically placed

(ii) unsymmetrically placed but transposed

9. What is the effect of unsymmetrical spacing of conductors in a 3-phase transmission line ?

10. Will capacitance of a transmission line depend upon the ground effect ?

11. Why do we find line to neutral capacitance in a 3-phase system ?

12. How does skin effect vary with conductor material ?

13. What is proximity effect ?