JNTU III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008
HIGH VOLTAGE ENGINEERING
(Electrical & Electronic Engineering)
1. Discuss the applications of insulating materials in construction of bushings.
2. (a) Mention the names of the gases which are used in the Electrical apparatus as an insulating medium.
(b) Discuss about the electrical properties of gases.
(c) Discuss about various physical conditions of gases to govern the ionization process.
3. What is internal discharge? How it is different from treeing and tracking. Explain these mechanisms briefly and discuss their affects on solid insulation breakdown in
4. (a) Explain a Cockroft-Walton circuit with a schematic diagram?
(b) Why is a Cockroft-Walton circuit preferred for voltage multiplier circuits?
5. (a) Discuss various methods of measuring high d.c and a.c currents.
(b) Mention various methods of measuring high impulse currents.
6. Give the mathematical models for lightning discharges and explain them.
7. Explain the concept of apparent charge in partial discharge measurements. Describe a simple experiment technique to measure partial discharge
8. Describe the impulse current tests performed on lighting arrestors. How do you conclude that the arrester has passed the test?