(i) Breakdown in Gases: Introduction to mechanism of breakdown in gases, Townsend’s
breakdown mechanism. Breakdown in electromagnetic gases. Application of gases in power
system.
(ii) Breakdown in Liquids: Introduction to mechanism of breakdown in liquids, suspended
solid particle mechanism and cavity breakdown. Application of oil in power apparatus.
(iii) Breakdown in solids: Introduction to mechanism of breakdown in solids,
electromechanical breakdown, treeing & tracking breakdown and thermal breakdown.
Units: II
(i) High DC Voltage Generation: Generation of high dc voltage, basic voltage multiplier
circuit.
(ii) High AC Voltage Generation: Cascaded Transformers.
(iii) Impulse Voltage generation: Impulse voltage, basic impulse circuit, Mark’s multistage
impulse generator.
(iv) Measurement of High Voltage: Potential dividers - resistive, capacitive and mixed
potential dividers. Sphere gap- Construction and operation. Klydonorgraph.
Units: III
Nondestructive Insulation Tests: (i) Measurement of resistively, dielectric constant and loss
factor. High Voltage Schering Bridge- measurement of capacitance and dielectric loss.
(ii) Partial Discharges: Introduction to partial discharge, partial discharge equivalent circuit.
Basic wide-band and narrow band PD detection circuits.
Units: IV
(i) Over voltages: Causes of over voltages, introduction to lightning phenomena, over
voltages due to lighting.
(ii) Travelling Waves: Travelling waves on transmission lines-open end line, short circuited
line, line terminated through a resistance, line connected to a cable, reflection and refraction at
a T-junction and line terminated through a capacitance. Attenuation of tavelling waves.
Units: V
(i) Over Voltage Protection: Basic construction and operation of ground wires- protection
angle and protective zone, ground rods, counterpoise, surge absorber, rod gap and arcing horn,
lighting arresters - expulsion type, non -linear gap type and metal oxide gapless type.
(ii) Insulation Coordination: Volt - time curves, basic impulse insulation levels, coordination
of insulation levels.