The Preparation Of Surface Micro-strip Insulator And Its Vacuum Surface Flashover Performance Reasearch

When the solid insulation material is applied in the devices with high vacuum,high voltage,strong current and rapid pulse,and its surface flashover occur easily.While the voltage that applied to the solid insulator is less than the breakdown strength of solid insulator.A large number of researches about vacuum surface flashover phenomenon of various materials indicated that:(1)The flashover voltage is closely related to the surface structure of the material.(2)Under the same experimental condition,the flashover voltage of insulator with metal composite is the highest.Inspired by the researchers' experimental research,this paper prepared a new kind of surface micro-strip insulator with cross-linked polystyrene and boron nitride ceramics as abstracted materials.The electric field distribution in the different structure of the insulator surface is simulated and the surface flashover property is studied.The research contents of this paper are followed:(1)a new type of surface micro-strip insulator is adopted and its micro-strip structure and material are designed and selected.(2)the cross-linked polystyrene/silver pulp and the boron nitride ceramics/ silver pulp surface micro-strip insulators are prepared by the coating method.(3)the Comsol Multiphysics finite element simulation software is used to simulated the strength of surface electric field for insulator with different micro-strip structure,and the relationship between the surface electric field distribution and the width,the quantity and the depth of conductive layer is studied.(4)the surface flashover voltage of different surface micro-strip insulators in vacuum is tested by flashover voltage test system,and the changes of its electrical properties is analyzed.(5)the surface morphology of the surface micro-strip insulator before and after the flashover test is observed by microscope.The main findings are:(1)Compared with the strength of electric field of the traditional insulator,the electric field intensity of the cross-linked polystyrene/silver pulp and the boron nitride ceramic/silver pulp micro-strip insulators have changed.With the increase of the width of conductive layer,the peak of electric field intensity increases.With the increase of the number of conductive layer,the peak of electric field intensity decreased.With the depth of conductive layer increase,the distribution and size of electric field intensity are basically keeping stable.(2)when the position and number of conduction layer in the surface micro-strip insulator are constant,with the increase of the permittivity of insulting material in the insulator,the distribution of electric field intensity is the same,but the peak of electric field intensity is slightly reduced.(3)For traditional insulators-the cross-linked polystyrene,the strength of electric field decreases as the total thickness of insulators increases.(4)Compared with the flashover voltage value of the traditional insulator,the flashover voltage of the cross-linked polystyrene/silver pulp and the boron nitride ceramic/silver pulp micro-strip insulator has been reduced.With the increase of the width of the conductive layer,the flashover voltage value is decreased.With the number of conductive layer increases,the flashover voltage value is increased.(5)When the position and number of conduction layer in the surface micro-strip insulator are constant,the flashover voltage value decreases with the increase of the permittivity of insulting material in the insulator.(6)For traditional cross-linked polystyrene insulators,the flashover voltage increase with the total thickness of insulators.(7)the surface of the micro-strip insulator has a serious ablation phenomenon after the flashover voltage occurred.