SF_(6)气氛中表面电荷对环氧树脂气固界面电子倍增过程的影响机制  

Effect of Surface Charge on Electron Multiplication Process of ER/SF_(6)Interface

作　　者：许航[1] 司马文霞[1] 孙魄韬 邵千秋 徐建伟 李闯[1] XU Hang;SIMA Wenxia;SUN Potao;SHAO Qianqiu;XU Jianwei;LI Chuang(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学电气工程学院输配电装备及系统安全与新技术国家重点实验室,重庆400044

出　　处：《高电压技术》2022年第5期1716-1725,共10页High Voltage Engineering

基　　金：国家自然科学基金(51837002;52077014);强电磁场环境模拟与防护重点实验室基金(6142205200103);国家重点研发计划(2017YFB0902702)。

摘　　要：为了研究表面电荷对绝缘介质气固界面电子倍增过程的影响机制,本文搭建表面电荷定量注入与沿面闪络动态观测平台。在SF_(6)气氛中通过非接触式电晕放电向环氧树脂表面注入定量电荷,根据光电倍增管探测放电发出的光信号判断沿面放电起始时刻,并对沿面放电起始电压UIFO和闪络电压UFO进行测量;同时通过Monte Carlo法求解SF_(6)中电子输运参数,结合Poisson方程计算沿面放电电子崩起始电压,并利用电子崩对流-扩散方程计算电子崩发展参数,研究表面电荷对沿面放电电子崩起始与电子崩发展的影响规律。研究结果表明:表面电荷一方面通过增强电极三结合点处场强,提高SF_(6)气体有效电离系数,促进电子崩起始;另一方面,积聚在电子崩发展临界长度xele内的表面电荷通过减小电子崩中空间电荷数量与增加电子崩头部半径阻碍电子崩的发展,抑制流注的形成,在两种机制的共同作用下,沿面闪络电压随着电荷沉积位置的变化呈现非单调性下降。To study the influence mechanism of surface charge on electron multiplication process of gas-solid interface,the surface charge injection and surface flashover dynamic observation platform was built.Surface charges were injected by non-contact corona discharge in SF_(6),and the discharge initial moment was determined by the pulse signal measured by photomultiplier,then the initiation voltage of electron avalanche(UIFO)and flashover voltage(UFO)were measured.To study the influence of surface charges on electron avalanche initiation and development,we calculated the UIFO,electron avalanche length and radius by Poisson equation and convection diffusion equation,respectively.The results indicate that surface charges increase the effective ionization coefficient of SF_(6) by enhancing the electric field at electrode triple junction points,which promotes the initiation of electron avalanche.Meanwhile,by reducing carriers number and increasing avalanche radius,surface charges accumulated on the critical length xele of avalanche prevent avalanche development.Under the action of above mechanisms,UFO decreases non-monotonically with the change of charge accumulation position.

关 键 词：表面电荷 闪络起始电压 闪络电压 临界场强 电子崩 

分 类 号：TM215.1[一般工业技术—材料科学与工程]