摘要
沿面放电是导致高频电力变压器气-固绝缘系统失效的主要原因之一。为研究空气-聚酰亚胺界面放电发展过程,该文基于流体动力学理论,通过对粒子输运方程、泊松方程和等离子化学反应的耦合表征,并充分考虑带电粒子在绝缘介质表面的反应过程和累积条件,建立了负极性脉冲电应力下空气-聚酰亚胺沿面放电等离子体模型。模型采用简化反应集定义空气放电涉及的粒子反应,模型复杂程度大幅降低。为避免求解过程中粒子密度出现负值,采用对数形式有限元法求解所建模型,实现了针-棒电极结构下1cm间隙沿面放电发展过程的动态模拟,得到了放电过程中带电粒子密度、表面电荷密度及电场分布等参量的时空演化规律,并通过实验从放电发展形态和表面电荷累积两方面验证了模型可靠性。基于该仿真模型,进一步探究了沿面放电的影响因素,结果表明,沿面放电平均传播速度与温度正相关,与气压负相关;界面二次电子发射系数越大,放电发展越迅速,表面电荷积聚越严重。
Surface discharge is one of the main reasons for the failure of the gas-solid insulation system of high-frequency power transformers.In order to investigate the evolution process of surface discharge,a simplified but effective set of reactions was used to describe all the particle reactions in air discharges.On this basis,a numerical model for discharge along air-polyimide surface was proposed with fluid dynamic theory,in which the transport equations of different particles,Poisson equation and plasma chemistry reactions in the discharge gap or channel were involved,along with the reaction process and accumulation of the charged particles on the dielectric surface.Then,the surface discharge evolution under the needle-to-bar electrode with 1 cm gap was investigated by simulations.Distribution and variation of particle density,surface charge density and electric field versus discharge time were obtained.The reliability of the model was verified by experiments from the aspects of discharge development morphology and surface charge accumulation.Accordingly,the influence of temperature,gas pressure and secondary electron emission on surface discharge was also studied and revealed.The results indicate that the discharge propagation velocity is positively correlated with temperature,and negatively correlated with air pressure.The larger the secondary electron emission coefficient,the faster the discharge develops and the more the surface charge accumulates.
作者
董国静
刘涛
李庆民
Dong Guojing;Liu Tao;Li Qingmin(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University,Beijing 102206 China;China Electric Power Research Institute,Beijing 100192 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2020年第9期2006-2019,共14页
Transactions of China Electrotechnical Society
基金
国家自然科学基金资助项目(51929701,51737005)。
关键词
沿面放电
流体模型
等离子体
电荷密度
电场分布
放电发展速度
Surface discharge
fluid model
plasma
charge density
electric field distribution
discharge propagation velocity
