负极性衰减振荡冲击电晕的数学物理模型

Mathematical Physical Model of the Corona Under Negative Damped Oscillatory Impulse

从气体放电微观物理过程出发,提出了一种负极性衰减振荡冲击电晕的数学物理模型,该模型考虑了碰撞电离、带电粒子迁移、空间光电离、电子与中性粒子的附着和带电粒子的复合。在已有文献的基础上,推导了同轴圆柱电极中的空间光电离公式。该模型可用来计算同轴圆柱电极中双指数冲击或衰减振荡冲击的负电晕伏库特性,计算结果与测量结果对比基本吻合。测量和计算结果表明,衰减振荡冲击下的伏库特性表现出明显的螺旋回环,这也是其与双指数冲击的主要区别。外施电压下降阶段,由于空间电荷的感应作用,内导体表面出现电场反向,有可能产生反极性电晕。利用提出的模型对反极性电晕过程中空间电场变化进行了定量分析。

Based on the microcosmic physical processes of gas discharge, a mathematical physical model ofthe corona under negative damped oscillatory im pulse is proposed in this paper. C ollision io niza tion, drift , spacephotoionization, attachment and recom bination are included in the proposed model. The space photoionizationform ula is deduced in a coaxial cylin d rica l geometry. The charge-voltage characteristics under the negative dampedoscillatory or the double exponential impulses can be computed by the proposed model. The computed results canagree reasonably w ith those observed from experimental measurement. Both measurement and computation showthat helical trajectories appear on the charge-voltage curves under damped oscillatory im pulses, w hich reveals them ain difference between the damped oscillatory and the double exponential impulses. In the decreasing range oftheapplied voltage, the electric fie ld near the inner conductor is found to undergo a reversal due to the induction ofspace charge. As aresult, the opposite polarity corona may occur. Using the proposed model, quantitativeanalysis is carried out for the electric fie ld in the development process of the opposite polarity corona.