Deepakkumar Yadav
Breakdown Mechanisms Short term breakdown Long term breakdown Short-Term Breakdown If electric field stresses are very high, failure occur in seconds or even faster without any damage to the insulating surface prior to breakdown. When applied voltage close to breakdown value, breakdown occurs in one or more discharges. When stress exceeds the critical stress at … Read more
Breakdown and Conduction in Solids Composite Dielectrics It is difficult to imagine complete (perfect) insulation system, in an electric equipment. We have combination of dielectric materials. The solids may have voilds, having filled with gases; liquids may have suspected solid impurities, dirt, dust etc. Insulation system having combination of more than dielectrics in series and … Read more
Alternative Liquid Insulators The use of mineral oil in conjuction with solid insulation is followed for many years. Esters Ester based fluids have good biodegradability and these have high flash point. The modern complex electrical supply system demands high degree of safety. Due to high flash point property esters are more safe. These are particularly … Read more
Transformer oil Filtration The transformer oil due to its repeated use comes in contact with moisture, dust, dirt, temperature, sludge formation and becomes impure and it is to be reconditioned so that it can be used again and again. For this purpose the oil is to be filtered in a filter plant. Due to filtration; … Read more
Transformer Oil Test The transformer oil should be checked during periodic maintenance as well as suitability of new oil to be decided. The sample is taken into a standard oil test cell. These tests are recommended as per I.S. (a) Crackle Test of Transformer Oil : It is initially a test aimed to determine the … Read more
Properties and Application of Good Transformer Oil and Agents which Contaminated Transformer Oil Transformer oil is used as di-electric coolant in transformers, switch gears, starters, regulators etc. The satisfactory performance of such equipment largely depends on the conduction and quality of transformer oil. The fresh oil has a pale clear yellow colour. The dark cloudy … Read more
Hydro Dynamic Model of Dielectric Breakdown When dielectric liquid is subjected to charge carriers, space charge is produced giving rise to coulomb’s force. The charge carriers are originated from electrode surfaces. The hydraulic instability is produced due to which convicting currents are initiated. Thus whenever conduction in a fluid is subjected to space chargers, convection … Read more
Conclusion of Conduction and Breakdown Commercial Liquids All the theories discussed above do not consider the dependence of breakdown system on the pap length. They all try to account for the maximum obtainable breakdown strength only. However, experimental evidence showed that he breakdown strength of a liquid depends on the gap length given by … Read more
Thermal Mechanism of Breakdown Q. Explain the various theories that explain breakdown in commercial liquid dielectrics. This mechanism is based on the experimental observations of extremely large currents just before breakdown . This high circuit pulses are believed to originate from the tips of the microscopic projections on the cathode surface with densities of the … Read more
Conduction and Breakdown Commercial Liquids Q. Explain clearly suspended particle mechanism of liquid breakdown. Figure A 1. Suspended particle theory In commercial liquids, the presence of solid impurities cannot be avoided These impurities will be present as fibers or as dispersed solid particles. The permittivity of these particles (∈2) will be different from the permittivity … Read more