沿绝缘介质表面的气体放电等离子体模型  

Plasma Model of Gas Discharge Along the Dielectric Surface

作　　者：司马文霞[1] 刘春香[1] 杨鸣[1] 邵千秋 邹密[1] 韩睿[1] 

机构地区：[1]输变电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400044

出　　处：《中国电机工程学报》2017年第9期2725-2733,共9页Proceedings of the CSEE

基　　金：国家重点基础研究发展计划项目(973项目)(2015CB251003);国家创新研究群体基金(51321063)~~

摘　　要：高压直流断路器的断口沿面绝缘性能失效已经成为阻碍直流开断技术发展的主要难点之一,而目前对沿面放电的动态发展规律和放电模型研究还很不完善。该文基于二维自洽流体模拟,建立了N_2/O_2等离子体沿面放电模型,考虑带电粒子的连续性方程和电子能量平衡方程,并耦合泊松方程求解。研究结果发现平板电极中放电由两端向中间发展,累积的表面电荷极性与外加电压一致。根据放电电流波形可判断沿面放电的发展阶段,其中电晕放电阶段电流幅值小且稳定,流注放电阶段电流有小幅波动,火花放电阶段出现电流激增。沿面放电发生在绝缘柱表面的薄层中,其中正、负空间电荷混合存在。并从沿面放电发展速度和表面电荷密度分布两方面验证了该等离子体模型的正确性。Insulation failure along the dielectric surface in the high-voltage direct-current （DC） circuit breaker has become one of the main difficulties in the development of DC switching technology. However, there is still a lack of complete understanding on the development rules of stages transformation and surface discharge models. A two-dimensional （2D） self-consistent fluid simulation of surface discharges of N~/O2 plasma was presented in this paper. This model solved the continuity equations for charged species and the electron energy balance equation, coupled with Poisson＇s equation. The results show that discharge develops from the both ends to the middle in the plates electrodes and it mainly accumulates negative charge on the dielectric surface under the negative voltage. The stage of surface discharge can be judged from the discharge current. It is corona discharge stage if the current amplitude is small and remains unchanged. There is a slight current fluctuation at the streamer discharge stage and a large current will appear at the spark discharge stage. Surface charge occurs in the thin layer of plasma along the dielectric surface which is filled with a mix of positive and negative charges. The correctness of the plasma model is verified from two aspects of the discharge development speed along the dielectric surface and the surface charge density distribution.

关 键 词：等离子体 放电电流 电场分布 电荷密度 放电发展速度 

分 类 号：TM85[电气工程—高电压与绝缘技术]