This document contains questions for an examination on high voltage engineering. It includes 9 questions covering various topics: 1. The advantages of transmitting power at high voltages and the need for generating high voltages in the laboratory. 2. Important applications of high voltages and medical and industrial applications. 3. Factors that affect gas breakdown and an explanation of Paschen's law and the minimum voltage for breakdown. 4. Thermal breakdown in solid dielectrics and the suspended particle mechanism in liquids. 5. The equivalent circuit of an impulse generator and why cascading of transformers is done. 6. The Cockcroft-Walton voltage multiplier circuit and a typical impulse current generator circuit.

1. EX-7201
B.E. VII Semester
Examination, December 2014
High Voltage Engineering
(Elective) Time: Three Hours
Maximum Marks: 70
Note: 1. Attempt All questions. 2. All questions carry equal marks.
1.a) Describe the advantages of transmitting electrical power at high voltages. Mtf What is
need for generating high voltages in laboratory.
OR
2.a) Explain the important application of high voltages.
b) Describe different medical and Industrial applications of high voltages.
3. a) Discuss the various factors which affect the breakdown of gases. State and explain
paschen's law. How do you account for the minimum voltage for break down under a given pd
conditions.
4. a) Explain thermal break down in solid dielectrics. How this mechanism is more significant
than the other mechanism, b) Explain clearly suspended particle mechanism of liquid
5. a) Draw a neat exact equivalent circuit of a impulse generator I and indicate the significance
of each parameter being used.
b) What is a cascaded transformer? Explain why cascading is done. Describe with neat
diagram a three stage cascaded trans fonner.
6. a) Explain with neat sketches cockraft walton voltage multiplier circuit.
b) Draw a typical impulse current generator circuit and explain its operation and application.
7. a) What are the requirements of a sphere gap for measurement of high voltages? Discuss the
disadvantages I of sphere gap measurements.
b) What are the problem associated with measurement of very high impulse voltages? Explain
how these can be taken care of during measurement?
OR
8. a) Discuss various resistance potential dividers and compare their performance for
measurement of impulse generator.
b) Discuss various methods of measurement of high impulse currents.
9. Write short note on any two of the following:
i) Testing of isolators
ii) Testing of circuit breakers
iii) Testing of cables
iv) Testing of transformers