LEVEL 1

1. Explain why bus-coupler is used.
2. What is a ring-bus bar system? Explain in brief.
3. What is the difference between class 1 and class 2 power transformer?
4. Explain the working of buchholz relay?
5. What is a core type transformer?
6. What is a shell type transformer?
7. Explain the four oil preservation system designs?
8. Explain why instrument transformers are used ?
9. Go through the specification of any current transformer.
10. How are transmission lines classified as? Explain them in brief.
11. What are the advantages and limitations of high transmission lines voltage.
12. What is kelvin’s law and what are its limitations?
13. Distinguish between A.C and D.C resistance of a conductor. Why the two differ ?
14. What is a plain break oil circuit breaker and what is its major drawback?
15. Write a note on water type circuit breaker.
16. What are the different type of air blast circuit breaker and expalin them in brief.
17. What are the methods of arc extensions? Explain them in brief.
18. What is arc voltage?
19. What is restriking voltage?
20. What is recovery voltage?
21. What is current chopping?
22. What is resistance switching?
23. Explain the construction and working of SF6 Circuit breaker.
24. Types of SF6 Circuit breaker.
25. Explain the construction and working of Vacuum Circuit breaker.

LEVEL 2

1. What might be the causes of transformer failure & what are the impacts?
2. What are the different types of faults that can occur in a transformer? Distinguish between internal and external fault.
3. What are the different types of protection given for transformer?
4. Why is differential protection most preferred in the case of transformer? What are the difficulties that have to be overcome for the same?
5. What are the major differences between instrument transformers used for measurement purpose and protection purpose?
6. Buchholz relay is a safety device used for all transformers. Justify.
7. Explain typical characteristics of magnetizing inrush currents.
8. Explain arc extinction in a circuit breaker.
9. What is the difference between switch & an isolator?