# EE6701 High Voltage Engineering Nov Dec 2016 Important Questions

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B.E/B.TECH DEGREE EXAMINATION NOV / DEC 2016
Seventh / 07th Semester
Department of EEE
EE6701 High Voltage Engineering
Nov Dec 2016 Important Questions
(Regulation 2013)

16 Marks Important Questions asked in previous years university examinations.

1. Give the origin and characteristics of switching surges and explain the causes of over voltages due to switching surges in EHV and UHV system. Explain the control measures for over voltage due to switching surge.
2. What are the different methods employed for lightning protection of overhead lines / Discuss in detail.
3. Explain the various theories of charge formation. Explain the mechanism of lightning strokes inducing high over voltages on transmission lines with the help of its mathematical model.
4. An underground cable of inductance 0.150 mH/km and of capacitance 0.2 Î¼F/km is connected to an overhead line having a inductance of 1.2 mH/km and capacitance of 0.006 Î¼F/km. calculate the transmitted and reflected voltage and current waves at the junction, if a surge of 200 kV travels to the Junction along with the cable and along the overhead line.
5. Explain the breakdown mechanism involved in commercial liquid dielectrics. Discuss the characteristics of liquid dielectrics.
6. Explain the breakdown mechanisms involving in solid dielectric breakdown
7. Derive an expression for the growth of current due to Townsend’s primary ionization. Assume necessary data.
8. Discuss the important properties of composite dielectrics. And explain the various mechanism of breakdown in composite dielectrics.
9. Discuss the various mechanisms of vacuum breakdown.
10. What is the principle behind the electrostatic method of energy conversion? Explain the construction and operation of Vandegraff generator with neat diagram.
11. A ten stage Cockcroft Walton circuit has all the capacitors of 0.04Î¼F. the secondary voltage of the supply transformer is 120kV at a frequency of 150 Hz. If the load current is 1.2mA, determine voltage regulation, ripple, the optimum number of stages for maximum output voltage and the maximum output voltage.
12. Explain the MARX circuit arrangement for multistage impulse generators.
13. Draw the circuit of an n-stage Cockroft-Walton circuit for generating very high DC voltages and explain its operation. Also derive an expression for the ripple content in the output waveform.
14. Tabulate and explain the methods used for the measurement of high voltages and high currents.
15. With neat sketch and explain the sphere gap arrangement method of high voltage measurement and give the factors influencing the measurement.
16. What is the principle behind the electrostatic voltmeter? Explain the construction, operation of electrostatic voltmeter and give its advantages and limitations.
17. Explain the various tests conducted in high voltage insulators.
18. Explain the power frequency and impulse voltage test conducted on bushings.
19. Discuss with a circuit arrangements, the detailed procedure for conducting impulse voltage testing of HV power transformer.
20. Explain the different aspects of insulation design and insulation coordination adopted for EHV systems.