复合绝缘子表面电荷动态积聚过程的PIC/MCC模拟

PIC/MCC Simulation of the Dynamic Process of Surface Charge Accumulation on Composite Insulators

局部放电是绝缘子表面电荷的主要来源。为了研究局部放电的复合绝缘子表面电荷的动态积聚过程,采用粒子网格法(PIC法)与Monte Carlo碰撞模型(MCC模型)相结合的方法(PIC/MCC法)跟踪了带电粒子运动轨迹,同时充分考虑了电子与气体分子之间的各种碰撞过程以及带电粒子空间分布对绝缘子电场的影响。计算结果表明:电子在电场作用下将运动到复合绝缘子阴极侧伞裙表面以及护套表面从而形成电荷积聚,伞裙表面电荷积聚量沿半径即径线方向先增加后减少,护套表面电荷积聚量则呈现出阴极侧较多的特点。比较计算结果与实验结果,其一致性较好,表明PIC/MCC法适用于模拟复合绝缘子表面电荷的动态积聚过程。

Partial discharge is the main source generating surface charge on insulators. In order to study the dynamic process of surface charge accumulation on composite insulators, we have developed a PIC/MCC method that combines the particle-in-cell method （PIC method） and the Monte Carlo collision model （MCC model） to track the motion of elec- trons, in which various kinds of collisions between electrons and gas molecules, as well as the effect of special distribution of charged particles on the electric field of insulators, are fully taken into consideration. The results show that under the influence of electric field, the electrons generated from gas discharges mainly accumulate on the surfaces of in- sulator jacket and umbrella close to the negative electrode side. The number of electrons firstly increases and then decreases along the outward radical direction on the umbrella surface, while it decreases along the insulator jacket from the negative electrode side. The simulation results are in accordance with experimental ones, showing that the proposed PIC/MCC method is fit to simulate the dynamic process of surface charge accumulation on composite insulators.