切向电场主导下C_(4)F_(7)N/CO_(2)混合气体中环氧复合材料表面电荷积聚特性及机理研究

Study on Surface Charge Accumulation Characteristics and Mechanism of Epoxy Composite Material in C_(4)F_(7)N/CO_(2)Mixture Under Severe Non-uniform Electric Field

气固界面的电荷积聚问题是诱发沿面闪络的重要原因,而当前C_(4)F_(7)N/CO_(2)混合气体中电荷积聚特性的相关研究还不够充分。为研究C_(4)F_(7)N/CO_(2)混合气体中表面电荷积聚特性及机理,本文通过指型电极构建极不均匀电场,测量了环氧复合材料在C_(4)F_(7)N/CO_(2)混合气体中的表面电荷分布特性;进一步的,为理清表面电荷来源及迁移特性,测量了冲击电压下C_(4)F_(7)N/CO_(2)混合气体中材料表面电位,比较了附加背板电极前后的表面电荷分布。研究表明,C_(4)F_(7)N/CO_(2)混合气体与SF_(6)中表面电位分布形态相似,均表现为高压电极附近积聚大量同极性电荷,地电极附近积聚少量异极性电荷。随着C4F7N含量升高,C_(4)F_(7)N/CO_(2)混合气体抑制电荷积聚能力增强。表面电荷来源于气体电离和高压电极注入并且随着电场强度的改变,电荷来源也发生变化,切向电场促进了电荷沿表面向更大范围的迁移。该工作对于明确C_(4)F_(7)N/CO_(2)混合气体中表面电荷积聚特性及环保型绝缘气体的推广应用具有重要意义。

Charge accumulation at gas-solid interface is an important cause of surface flashover.The charge accumulation characteristics in C_(4)F_(7)N/CO_(2)mixtures have not been sufficiently studied.To investigate the characteristics and mechanism of surface charge accumulation in C_(4)F_(7)N/CO_(2)mixture,the surface charge distribution characteristics of epoxy composite insulation in C_(4)F_(7)N/CO_(2)mixture were measured by constructing a severe non-uniform electric field with finger-type electrode.In order to further clarify the surface charge accumulation mechanism,the surface potentials of the material in the C_(4)F_(7)N/CO_(2)mixture were measured under the impulse voltage and were compared with that after attaching a back-plate electrode.The study shows that the surface potential distribution in the C_(4)F_(7)N/CO_(2)mixture is similar to that in SF_(6),showing that a large number of homopolar charges accumulate near the high voltage electrode and a small number of heteropolar charges accumulate near the ground electrode.As the C4F7N content rises,the charge suppression ability of the C_(4)F_(7)N/CO_(2)mixture increases.The surface charges are derived from gas ionization and electrode injection and the mechanism is converted with the electric field.With the tangential electric field facilitating,the charges migrate along the surface to a larger area.This work is of great significance for the clarification of the surface charge accumulation characteristics in C_(4)F_(7)N/CO_(2)mixture and the promotion of eco-friendly insulation gas applications.