IMPORTANT QUESTIONS OF PERFORMANCE OF TRANSMISSION LINES:
1. What is the purpose of an overhead transmission line ? How are these lines classified ?
2. Discuss the terms voltage regulation and transmission efficiency as applied to transmission line.
3. Deduce an expression for voltage regulation of a short transmission line, giving the vector diagram.
4. What is the effect of load power factor on regulation and efficiency of a transmission line ?
5. What do you understand by medium transmission lines ? How capacitance effects are taken into account
in such lines ?
6. Show how regulation and transmission efficiency are determined for medium lines using
(i) end condensor method
(ii) nominal T method
(iii) nominal π method
Illustrate your answer with suitable vector diagrams.
7. What do you understand by long transmission lines ? How capacitance effects are taken into account in such lines?
8. Using rigorous method, derive expressions for sending end voltage and current for a long transmission line.
9. What do you understand by generalized circuit constants of a transmission line? What is their importance?
10. Evaluate the generalized circuit constants for
(i) short transmission line
(ii) medium line — nominal T method
(iii) medium line — nominal π method
11. What is the justification in neglecting line capacitance in short transmission lines ?
12. What are the drawbacks of localized capacitance methods ?
13. A long transmission line is open circuited at the receiving end. Will there be any current in the line at the sending end ? Explain your answer.
14. Why is leakage conductance negligible in overhead lines ? What about underground system ?
15. Why do we analyze a 3-phase transmission line on single phase basis ?