真空中固体绝缘沿面闪络现象的研究进展

Research Progress on Surface Flashover Phenomena Across Solid Insulation in Vacuum

针对长期以来高电场下复合绝缘系统的耐电性能受绝缘材料的沿面闪络现象所限制,严重制约了很多电气电子系统的整体性能的现状,迫切需要深入研究真空中绝缘子沿面闪络现象,为此,综述了国内外相关研究现状和进展,认为此现象是一种发生在高电场下的复杂界面(电极与材料的交界面)和表面(材料的表面)的物理现象。闪络过程在本质上反映出高电场下的电荷行为,由体内(材料的表层内)和体外(材料的表面及表面以上)2过程支配。需综合考虑绝缘材料的介电常数、电阻率、二次电子发射特性、表面陷阱分布等影响因素,进而提出表征和改善真空中沿面闪络特性的综合评价体系,最终达到认识新的物理现象并将之有效调控的目的。

The electric strength of composite insulation system is always determined by the surface flashover phenomena of its insulating materials, which greatly limits the overall performance of many electrical and electronic systems. The state-of-the-art of flashover across solid insulation in vacuum is reviewed. It is considered as a kind of complex interface （the boundary of electrode and material） and surface （the surface of material） physical phenomena occurred under high electric field. Essentially flashover process reveals the charge behaviors under high field, consisting of two processes, i. e. , the bulk （inside surface layer of a material） and outside （on and above surface of a material） processes. It is needed to synthetically consider the influential factors such as relative permittivity, electric resistivity, secondary electron emission behavior and surface trap distribution of insulation, henceforth to propose the general evaluation system for characterizing and mending flashover characteristics, and to ultimately understand new physical phenomena and efficiently control them.