HIGH VOLTAGE ENGINEERING Question paper Nov/Dec 2010

B.E/B.Tech Degree Examination November/December 2010, 
Seventh Semester, 
Electrical and Electronics Engineering, 

Answer all the questions.


1. What are the causes of over voltage in a power system in few words?
2. Differentiate switching surge from lightning impulse.
3. What is ionization by collision?
4. Define Gas law.
5. Draw the simple voltage doubler circuit.
6. What is Deltatron circuit?
7. What are the advantages of CVT?
8. What are the merits of series resistance micro ammeter method?
9. Define 50% flash over voltage.
10. What are the tests conducted on power transformers?

11.(a)(i) What are the causes for switching and power frequency over voltage? How they are controlled in power system? (12)
(ii) Explain lightning phenomena. (4)
11.(b) What are the different methods employed for lightning protection of over head lines? Discuss in detail. (16)

12.(a) Explain the primary and secondary breakdown mechanism of gaseous dielectrics. (16)
12.(b)Explain the various breakdown theories involved in commercial liquid dielectrics. (16)

13.(a) Draw and explain the circuits for producing impulse waves. (16)
13.(b)Explain any one method of generating HV AC at power frequency and discuss its limitation/feature. (16)

14.(a) Discuss the various techniques for the measurement of impulse voltage. (16)
14.(b)With a neat sketch explain the sphere gap measurements for peak voltage measurement. (16)

15.(a) Discuss the various tests carried out in a circuit breaker at HV labs. (16)
15. (b) What is the significance of impulse tests? Briefly explain the impulse testing of insulators. (16)