6EE6.3 HIGH VOLTAGE ENGINEERING
 

1. BREAKDOWN IN GASES: Mechanism of breakdown in gases, Townsend's or kenal mechanism of spark, Paschen's law.

2. BREAKDOWN IN LIQUID AND SOLID DIELECTRICS: Mechanism of breakdown in liquids suspended particle theory cavitation and bubble mechanism, stressed oil volume mechanism, mechanism of breakdown in solids: Intrinsic break dwon. Electromechanical break down, break down due to treeing and tracking, thermal break down, thermal breakdown time.

3. GENERATION OF HIGN VOLTAGE: Methods of generation of power frequency high voltage: cascaded transformers and resonance transformers Generation of high voltage DC, voltage multiplier circuits. Electrostatic Generation:Van de Graff machine and its voltage stabilisation. Impulse voltage generation.:Basic impulse circuit,single stage impulse generator, multistage impulse generator (Marx circuit)

4. MEASUREMENT OF HIGH VOLTAGE: Potential dividers:resistive,capacitive and mixed dividers for high voltage, sphere gap:construction mounting,effect of nearby earth objects, effect of humidity and atmospheric conditions,effect of irradiation and polarity. Ryall crest voltmeter, Electrostatic voltmeter:Principle and classification.Constructional details of an absolute electrostatic voltmeter. Measurement of dc high voltage. Measurement of impulse voltage:Klydonograph. Oscilloscope and its application in high voltage measurement.

5. OVER VOLTAGES: Accumulation of charge in clouds. Direct & Indirect strokes, isokeraunic level, switching surges.

6. PROTECTION OF SYSTEM AGAINST SURGES: Ground wires, protective angle,tower footing resistance,surge diverters. Gap type and gapless lightning arresters. Insulation coordination, basic insulation levels. Voltage-time curve, impulse ratio.

RECOMMENDED BOOKS:

1. Thaper, High voltage Engg. 2. Wadhwa:High voltage Engg. 3. Kamaraj Naidu:High voltage Engg. 4. Richjovij:High voltage Engg.