| Epoxy resin is the raw material of basin insulator support in GIS/GIL.Due to the assembly of GIS/GIL and insulation wear,metal,insulation and semiconductor dust will accumulate on the insulator surface,which seriously threatens the safe and stable operation of GIS/GIL.In recent years,the phenomenon of electrified insulator surface has attracted more and more attention of researchers.In this paper,various types of dust attached to the surface of epoxy resin are taken as the research object,and the surface charge characteristics and flashover characteristics along the surface under AC voltage are studied.The surface charge characteristics of the samples were measured.Dust of three kinds of materials and four kinds of particle radius with a certain quality was selected to prepare the dust attached samples,which were attached to a specific area.The samples were charged by corona respectively after the dust was attached.The accumulation and dissipation characteristics of the positive and negative surface charges of different samples were studied.The results show that the initial charge accumulation of samples decreases with the decrease of metal dust particle size,and the surface charge dissipation rate increases with the decrease of metal dust particle radius;the initial charge accumulation of samples decreases with the decrease of insulating dust particle radius,and the charge dissipation rate slows down;the initial charge accumulation of samples decreases with the decrease of semiconductor dust particle radius increases first and then decreases,and the charge dissipation slows down first and then increases.The flashover characteristics along the surface of dust-attached samples under AC voltage are analyzed.SF6 and 20%C4F7N-80%CO2,which are the common insulating gases in GIS/GIL,are selected as the gas conditions for surface flashover test.The results show that the surface flashover voltage of different types and radius of the dust-attached samples in the two gas environments is increased with the decrease of metal dust particle radius d,while that of the samples is increased with the decrease of semiconductor and insulation dust particle radius d.Compared with the AC flashover characteristics of the samples with different dust materials,the samples with metal dust are most prone to flashover,followed by the semiconductor dust,and the samples with insulation dust have the highest flashover voltage.The influence of dust particle radius on the surface electric field distribution and its relationship with surface charge characteristics and surface flashover characteristics are explained.The electric field distribution between samples with different particle radius was observed,and the electric field simulation results were used to analyze the charge characteristics,flashover characteristics and the relationship between them.Based on the above research,the influence of metal,semiconductor and insulation dust in GIS/GIL on the surface charge characteristics and flashover characteristics of epoxy resin insulation is given,which provides theoretical basis for dust pollution prevention,insulation performance evaluation and insulation structure design in GIS/GIL. |
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