DHANALAKSHMI COLLEGE OF ENGINEERING CHENNAI
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
EE2353 - HIGH VOLTAGE ENGINEERING
UNIT I
PART A
1. Define – Surge Impedance of a transmission line
2. Define – Isokeraunic Level
3. List out the different kinds of over voltages.
4. Compare lightning surges with switching surges.
5. What is meant by switching surges?
6. What is basic impulse level (BIL)?
7. Define – Indirect Stroke
8. What is meant by stepped leader stroke?
9. How is attenuation and distortion caused?
10. What is meant by back flashover?
PART B (16 Marks)
1. Explain in detail, the various protection schemes for overhead lines.
2. Explain in detail, the technique of modeling the lightning.
3. Explain in detail, the theories of charge formation in thunder clouds.
4. Explain the importance of insulation coordination.
(10)
(8)
(16)
(8)
5. Explain in detail, the different methods employed for lightning protection of overhead lines.(16)
6. Explain in detail, the characteristics of switching surges and also explain the causes of over
voltage due to switching surges in EHV and UHV system.
(10)
7. Explain the different methods of protection against over voltages.
(8)
8. Explain the causes of power frequency over voltages in power system.
(8)
9. Explain the protection of transmission lines using protection devices.
(8)
UNIT - II
PART A
1. What is meant by composite dielectric?
2. Define – Paschen’s Law
3. What is meant by Townsend’s discharge?
4. What are called electronegative gases?
5. What is meant by corona discharges?
6. What are the requirements of good solid dielectrics?
7. Define – Treeing and Tracking
8. What is meant by intrinsic strength of a solid dielectric?
9. Write the various mechanism of vacuum breakdown.
10. What is meant by ionization by collision?
PART B
1. Explain in detail, the streamer theory of breakdown in air at atmospheric pressure.
Derive the criterion for breakdown in electronegative gases.
(16)
2. State the criteria for sparking potential and hence obtain the relation between sparking
potential and (pd) values (Paschens Law). Discuss on the nature of variation of sparking
potential with (pd) values.
(16)
3. Explain in detail, the breakdown of vacuum medium.
(16)
4. Explain in detail, the breakdown mechanism in non-uniform fields and phenomenon of
Corona.
(16)
5. Explain in detail, the breakdown mechanism involved in commercial liquid dielectrics.
(16)
6. Explain in detail, the various theories that explain the breakdown mechanism in liquid
dielectrics.
(8)
7. Explain the ageing and breakdown in composite dielectrics due to partial discharge.
(8)
8. Explain in detail, the Cavitation theory and Bubble theory in liquid breakdown.
(8)
UNIT 3
PARTA
1. What is meant by tesla coil?
2. How is the circuit inductance controlled and minimized in impulse current generators?
3. List out the specifications of the standard impulse voltage.
4. Write any two methods of switching surge generation in laboratory.
5. What are the advantages of generating HV using Resonant Transformer?
6. Write the components of a multistage impulse generator.
7. List out the merits of Vande Graff generator.
8. List out the advantages of HVDC.
9. What is meant by Deltatron circuit?
10. What are the advantages of cascaded transformer method?
PART B
1. Explain in detail, the Marx circuit arrangement for multistage impulse generators. How
is the basic arrangements modified to accommodate the wave time control resistances?
(16)
2. What is the principle behind the electrostatic method of energy conversion? Explain the
construction and operation of Vande graff generator.
(16)
3. Explain in detail, the tripping and control of impulse generators with Trigatron gap
arrangements.
(16)
4. Explain in detail, the circuits for producing impulse waves.
(16)
5. Explain in detail, the impulse current generation using capacitor bank.
6. Explain the components of multistage impulse generator.
(8)
(8)
UNIT - 4
PART A
1. Why are capacitance voltage dividers preferred for high a.c. voltage measurements?
2. State the disadvantages of CVT method of measurement.
3. How the stray effect is reduced in resistive shunt type of measurement?
4. Give the advantages of electrostatic voltmeter.
5. Define Capacitance voltage transformer (CVT)
6. Explain the basic principle of Hall generator.
7. List some advantages of Faraday generator.
8. What are the advantages of generating voltmeters?
9. What are the advantages of CVT?
10. What is Rogowski coil?
PART B
1. With neat sketch explain the sphere gap arrangement method of high voltage
measurement and give the factors influencing the measurement. (16) (Nov -Dec 2011)
2. Tabulate and explain the methods used for the measurement of high voltages and high
currents.
(16) (Nov -Dec 2011)
3. What is the principle behind the electrostatic voltmeter? Explain the construction,
operation of electrostatic voltmeter and give its advantages and limitations.
(16) (May - June 2012)
4. What is Capacitance Voltage transformer? Explain with phasor diagram how a tuned
CVT can be used for high voltage measurement in power systems.
(16) (Nov -Dec 2006)
5. With a block diagram, illustrate the measurement of HVAC using digital technique.
(16) (Nov -Dec 2008)
6. Discuss the various techniques for the measurement of impulse voltage.
(16) (Nov -Dec 2010)
7. Compare the merits and demerits of measuring very high voltages using sphere gaps
and potential dividers.
(8) (April-may2008)
8. Describe the generating voltmeter method for measuring high d.c. voltages.
(8)(April-may2008)
9. Explain the faraday generator method of measurement.
(8) (May - June 2012)
10. Explain the electro optical method of high power frequency alternating current
measurement.
(8)(May - June 2012)
UNIT V
PART A
1. What are the different tests conducted on insulators?
2. Classify the types of tests to be conducted for HV apparatus.
3. What do you mean by type tests and routine
4. Define partial discharge.
5. Write the standard atmospheric conditions for HV testing as per Indian standard.
6. Define creeping distance.
7. Define 5O% flash over voltage.
8. What are the tests conducted on power transformers?
9. What are the tests conducted on surge arrester?
10. What is insulation coordination?
PART B
1. Explain the method of impulse testing of high voltage transformers. What is the procedure
adopted for locating the fail arc.
(16) (April-May 2010)
2. Discuss the dielectric power factor test and partial discharge test conducted on high voltage
cables.
(16) (Nov -Dec 2011)
3. What are the tests conducted on isolators and circuit breakers explain in detail?
(16) (May - June 2012)
4. Explain the various tests conducted in high voltage insulators,
5. Explain the following
(16) (May - June 2013)
(16)(Nov -Dec 2012)
(1) Flashover voltage
(2) Withstand voltage
(3) Impulse voltage
(4) Creep age distance.
6. (j) Why is the synthetic testing advantageous over the other testing methods for short circuit
tests?
(4) (April-May 2010)
(ü) Explain the different aspects of insulation design and insulation co-ordination adopted for
EHV systems.
(12) (April-May 2010)
7. (i) Explain the need for high voltage testing of electrical apparatus
(ii) Mention the different types and ‘nature of tests conducted.
(4) (April-may2008)
8. Discuss the arrangement with detailed procedure for conducting wet withstand tests and state
specification for water used in such tests.
(8) (April-may2008)
9. What are the tests done on Bushings? Explain them.
(8) (May - June 2009)
10. Explain the synthetic testing of circuit breakers.
(8) (May - June 2009)