Study On The Electrical Properties Of Epoxy Resin Insulation Materials In Low Temperature Environment

There are very cold areas in the north of China,The temperature in these areas is a long time below-40?.Electrical equipment in the extremely cold area is unavoidable for a long time to work in severe low temperature environment.At present,The research on insulation materials in the cold area is less in our country and there are security risks in Electrical equipments.So it has important theoretical and practical significance to study the electrical characteristics and the variation law of the insulation material at low temperature.Filler can improve the performance of epoxy resin,and Al2O3 particles are commonly used as filler in casting insulators.We prepared epoxy resin composites with micron Al2O3 filler content of 75%,20%,50% and 0%.We erected the low temperature environment test platform.The test platform includes low temperature test chamber,power supply system and temperature control system and the test platform can realize adjustable temperature in the range of 150?~-70?.Using the low temperature test platform,We studied the permittivity,the tg?,the breakdown strength and the surface flashover voltage of epoxy resin insulation material in the range of-70?~20?.The result shows that:1.Adding micron Al2O3 filler can reduce the dielectric loss angle factor of epoxy resin insulation material.at 20?~-70?,as the temperature increasing,the dielectric loss factor increases at first and then decreases.The temperature of the maximum dielectric loss factor will be decreased with the addition of micron Al2O3 filler to the epoxy resin.2.The permittivity of epoxy resin insulation material at different temperature increases with the increase of the content of Al2O3 in micron.When the filler is less than20%,the relative dielectric constant of the epoxy resin insulation material increases with the increase of the filler.The change law of the permittivity of the epoxy resin is almost independent of the temperature.3.The electrical strength of epoxy resin in power frequency is increased with the temperature increasing at 25? ~-60?.At the same temperature.The average breakdown strength of epoxy resin is decreased with the increase of the filler content of micron Al2O3.4.The surface flashover voltage of pure epoxy resin increases with the temperature increasing in the range from 20? to-70?.The addition of filler will reduce the surface flashover of epoxy resin from the overall trend.The surface flashover voltage of the pure epoxy resin is higher than that of the filler material at all temperatures.