Electrostatic fields and field stress control:
Electrical field distribution and breakdown strength of insulating materials - fields in homogeneous, isotropic materials - fields in multi-dielectric, isotropic materials.
Numerical analysis of electrical fields in high voltage equipment:
numerical methods - Charge simulation method (CSM), Finite Difference Method (FDM), Finite Element Method (FEM), The boundary-element method, Comparative summary, Formulation of the finite-element equations in two and three dimensions - Forming the functional equation, The energy functional illustrated, Numerical representation.
Electrical breakdown in gases:
Gases as insulating media - ionization and decay processes, Townsend first ionization coefficient, photo ionization, ionization by interaction of metastable with atoms, thermal ionization, deionization by recombination, deionization by attachment–negative ion formation, examples - cathode processes – secondary effects, photoelectric emission, electron emission by positive ion and excited atom impact, thermionic emission, field emission, Townsend second ionization coefficient, secondary electron emission by photon impact, examples - transition from non-self-sustained discharges to breakdown, the Townsend mechanism, examples - the streamer or ‘kanal’ mechanism of spark, examples - the sparking voltage– Paschen’s law, penning effect.
Breakdown in liquid :
Liquid as insulators, breakdown in liquids - electronic breakdown, suspended solid particle mechanism, cavity breakdown, examples - static electrification in power transformers, transformer oil filtration, transformer oil test, alternative liquid insulations like vegetable oils, esters and silicon oils.
Generation of high voltages:
Generation of high direct voltages, half and full wave rectifier circuits, voltage multiplier circuits, Van de Graff generators, electrostatic generators, examples - generation of alternating voltages, testing transformers, cascaded transformers, resonant transformers, examples - impulse voltages, Standard lightning and switching surge and associated parameters and their corrections, design and construction of impulse voltage generator circuits, Marx circuit, operation, examples - impulse current generator.
Measurement of high voltages:
High direct voltage measurement, peak voltage measurements by spark gaps, sphere gaps, reference measuring systems, uniform field gaps, rod gaps, factors affecting sphere gap measurements, examples - electrostatic voltmeters - ammeter in series with high ohmic resistors and high ohmic resistor voltage dividers.
High voltage testing:
Testing of insulators and bushings, testing of isolators and circuit breakers Testing of cables, testing of transformers - testing of surge diverters.
Course Outcome:
1. Apply numerical methods for engineering problem. (Applying) -20%
2. Recall breakdown mechanism for dielectric materials in solid, liquid and gaseous state. (Remembering) -20%
3. Classify insulation test techniques. (Understanding) -20%
4. Examine methods for generation of test high voltage and as well for its measurement. (Analyzing).-20%
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