沙尘环境下接触网绝缘子电场分布的仿真研究

发布时间：2018-08-08 21:24

【摘要】：我国西北地区植被稀疏，土地荒漠化导致的沙尘暴已经严重影响了铁路运输生产的安全运行。沙尘天气不仅加速了沙尘在绝缘子表面的沉积，还使绝缘子周围的清洁空气变成了空气和悬浮沙粒的混合媒质，并且在空间中形成了强烈的沙尘电场。工作环境的改变会影响绝缘子的电场分布，从而可能导致闪络，研究沙尘环境下接触网绝缘子的电场分布可为同环境下绝缘子闪络等相关研究提供参考依据。本文以电气化铁路接触网专用的QBN-25型号腕臂棒形瓷绝缘子为研究对象，基于静电场有限元法建立了沙尘环境下绝缘子电场数值计算的仿真模型。应用人工截断法设置合理的空气域边界，将绝缘子电场分布问题的求解由无限开区域转化为有限闭区域，并设置无限元区域解决了绝缘子电场的远场耗散问题。针对悬浮沙粒数量巨大，普通计算机无法计算的问题，根据模型的轴对称特性和网格剖分的可操作性，，制作了完整几何模型的简化模型，大幅提高了仿真效率。应用COMSOL Multiphysics有限元软件计算分析了在绝缘子表面覆沙、沙尘电场、空气中悬浮沙粒等沙尘环境下绝缘子沿面电场的分布特性。仿真结果表明：绝缘子沿面电位和电场分布受绝缘子几何形状影响明显；绝缘子表面沉积沙尘会降低覆沙处的场强；当沙层中出现无沙带时，无沙带处的场强将会升高；沙尘电场会使绝缘子圆周方向的电场发生改变；空气中悬浮的电中性沙粒可小幅畸变绝缘子沿面电位和电场；悬浮沙粒带上相同的电量后，绝缘子沿面电位和电场的畸变幅度加大，其畸变幅度受悬浮沙粒的粒径、数量、带电量的大小和极性影响明显；混合粒子群对绝缘子沿面电位和电场的畸变幅度受粒子群中沙粒的带电特性影响明显。各种沙尘环境均会不同程度畸变绝缘子沿面电场，各具特点，悬浮沙粒带电是绝缘子沿面电场畸变的重要原因。
[Abstract]:The sparse vegetation and the dust storm caused by land desertification have seriously affected the safe operation of railway transportation production in northwest China. The dust weather not only accelerates the deposition of dust on the insulator surface, but also makes the clean air around the insulator become a mixed medium of air and suspended sand particles, and forms a strong dust electric field in space. The change of working environment will affect the electric field distribution of insulators, which may lead to flashover. The study of electric field distribution of catenary insulators in sand dust environment can provide reference for the study of insulator flashover in the same environment. In this paper, the electric field simulation model of QBN-25 type wrist-arm rod porcelain insulator for catenary of electrified railway is established based on the finite element method of electrostatic field. Using artificial truncation method to set reasonable air boundary, the solution of insulator electric field distribution problem is transformed from infinite open region to finite closed area, and the far-field dissipation problem of insulator electric field is solved by setting infinite element region. According to the axisymmetric characteristics of the model and the maneuverability of mesh generation, a simplified model of complete geometric model is made, which greatly improves the efficiency of simulation. The distribution characteristics of the insulator electric field along the surface of the insulator in the environment of sand coated on the surface of insulator, dust electric field and suspended sand particles in the air are calculated and analyzed by using the COMSOL Multiphysics finite element software. The simulation results show that the distribution of potential and electric field along the insulator surface is obviously affected by the geometry of the insulator, the sand dust deposited on the surface of the insulator will reduce the field strength of the sand covered area, and the field strength will increase when there is no sand zone in the sand layer. The dust electric field changes the electric field in the circumferential direction of the insulator; the electric neutral sand particles suspended in the air can slightly distort the insulator surface potential and electric field; after the same electric quantity on the suspended sand belt, The distortion amplitude of insulator along the surface potential and electric field is increased, and the distortion amplitude is obviously affected by the particle size, quantity of suspended sand, the size and polarity of the band electric quantity. The effect of mixed particle swarm on the surface potential and electric field distortion of insulator is obviously affected by the charged characteristics of sand particles in the particle swarm. All kinds of sand and dust environments will distort the electric field along the insulator to varying degrees, and each has its own characteristics. The suspended sand charged is an important reason for the distortion of the insulator's electric field along the insulator's surface.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM216;U225

【参考文献】