Introduction: Electric field stress, gas, liquid, solid and composite dielectrics.

Conduction and Breakdown in Gases: Gases as Insulating Media, Collision Process – types of collision, Mobility of ions and electrons. Ionization Processes- Ionization by collision. Townsend’s Current Growth Equation–Current Growth in the Presence of primary and Secondary Processes, Townsend’s Criterion for Breakdown, Breakdown in Electronegative Gases, Time Lags for Breakdown, Paschen’s Law, Corona Discharges.

Conduction and Breakdown in Liquid Dielectrics: purification of liquid dielectrics, Breakdown in Liquid dielectrics. – Suspended particle, bubble and stressed oil volume mechanism.

Conduction and Breakdown in Solid Dielectrics: Intrinsic Breakdown, Electromechanical Breakdown, Thermal Breakdown.

Generation of High Direct Current Voltages: Voltage Doubler circuit, Voltage multiplier circuit- Cockcroft Walton circuit, Ripple and voltage drop in multiplier circuit. Vandegraaff generator.

Generation of High Alternating Voltages: Cascade transformers, Resonant transformers, Tesla coil.

Generation of Impulse Voltages and currents: Standard impulse wave, Circuit for producing impulse waves- Analysis of impulse generator RLC circuit, Wave shape control, Marx circuit , Generation of impulse current: standard impulse current wave ,Circuit for producing impulse current wave.

Measurement of High DC Voltages and Currents: Measurement of High DC Voltages – Series Resistance micro ammeter, Resistance potential divider, Generating voltmeter.

Measurement of High AC voltages– Series impedance voltmeter, Series capacitance voltmeter, Capacitance potential dividers, Capacitance voltage transformers. Electrostatic voltmeter, series capacitance peak voltmeter (chubb-Fortscue method), Spark gaps for measurement of High dc, ac and Impulse voltages – Spark gap measurements, Factors influencing the spark over voltage of sphere gaps.

Measurement of Impulse Voltages– Resistance potential dividers, capacitance voltage dividers, Mixed R-C potential dividers Peak reading voltmeters for impulse voltages. Measurement of High DC, AC and impulse Currents– Hall generator, Resistive shunt, Rogowski coils and Magnetic links.

Natural Causes for Over voltages
Lightning phenomenon: Charge formation in the clouds, Mechanism of lightning strokes, Mathematical model for lighting, Over voltages due to indirect stroke.

Power frequency Overvoltage: Sudden load rejection, Ferranti effect. Control of over voltages due to switching.

Protection of transmission lines against over voltages: Using shielded or ground wires, Ground rods and counter poise wires, Surge arresters -Protector tubes, Nonlinear element surge arrestor.

Non-Destructive Testing of Materials and Electrical Apparatus Power frequency measurements- Schering bridge for audio frequency, transformer ratio arm bridge. Partial discharge measurements- straight discharge detection, Balance detection.

High Voltage Testing of Electrical Apparatus– Testing of insulators, bushings, circuit breakers, cables. Testing of transformers- Impulse test, Tests on surge arrestors.