接触网绝缘子电晕放电特性仿真研究

Simulation study on corona discharge characteristics of insulators on the contact wire

为研究接触网绝缘子电晕放电特性,提出基于化学反应与流体力学结合的绝缘子电晕放电2维数值模型,采用数值仿真模拟计算,分析在绝缘子电晕放电过程中电场强度、电子数密度、电子温度和正离子数密度的动态分布。通过分析瞬态仿真数据可知,绝缘子的沿面电场受绝缘子形状的影响较大,在金具两端和曲率半径较大的伞裙外边沿容易形成电离区,电离区场强随放电时间的改变较大;电子温度分布与电场分布的变化趋势相近;阴极区域,电子密度随放电时间的增加缓慢增加,阳极和伞裙边沿区域电子密度出现最大值;放电过程中N2的电子碰撞电离反应是电子产生的主要方式,但由于电离阈值能量和电荷转移等原因O2+比N2+的离子数密度大;本文提出的绝缘子电晕放电2维数值模型可真实模拟绝缘子电晕放电的暂态过程,对研究电晕放电的物理机理具有重要意义。

In order to investigate the corona discharge characteristics of contact wire, chemical reaction and fluid mechanics were combined to propose a two-dimensional numerical model of corona discharge. Simulation calculation and analysis of dynamic distribution of electric field intensity, electron density, electron temperature, ion density in insulator corona discharge were processed by numerical simulation. Through the analysis of the transient simulation, data shows that the insulator surface electric field is influenced by the shape of the insulator is larger. In the metal at both ends and the radius of curvature of the larger outer edge of the umbrella skirt easy to form ionization area, ionization field strength with the discharge time changes. The electronic temperature distribution and the electric field distribution have similar regulars. In the vicinity of the cathode, the electron density increases slowly with the increase of time, the maximum density of electron in the edge area of the anode and umbrella skirt. The electron impact ionization reaction of N2 is the main way of electron production, but the ion density of O_2~＋ is higher than that of N_2~＋ due to ionization threshold energy and charge transfer. In this paper, the two-dimensional numerical model of corona discharge of insulator can simulate the transient process of corona discharge of insulator, which is of great significance to study the physical mechanism of corona discharge.