西部沙尘地区电气化铁路接触网绝缘子污闪特性及在线监测技术研究

As the acreage of desertification is gradually increasing in Chinese western area year by year, which doing harm to the insulation of high-tension transmission lines seriously. Studying the influence of this working environment of dust on the distribution of insulators on catenaries can provide the corresponding theoretic evidence of the insulators’ flashover under the dust.. Firstly, a mathematical model of electromagnetic field was built to illustrate the electric field distribution of the insulators on catenaries. Then the boundary conditions were structured and transformed to the corresponding finite element model. Secondly, a three dimensional geometric model was build to simulink the insulators on catenaries under the dust. According to the specialties of the entity inside the model differed widely in scale, grids as well as high computational complexity, the model was simplified reasonably to increase the efficiency of simulation and the method of geometric modeling was raised. Thirdly, through the calculation from finite element simulation, the characteristics of the electric distribution of insulators on catenaries influenced by different dust factors were discovered. In laboratory, a measurement system was built to measure the electric distribution of the insulators as well as verify the simulation results. Finally, summarize the results and put forward the influences by different level of dust pollution on insulators’ performances. Then, provide early warning value of the pollution level and the electric field strength when flashover appears of the insulators on catenaries caused by the dust. Furthermore, insulators effective monitoring scheme in the dust environment were raised aiming at the insulators’ designing, operating and maintenance.

随着我国西部沙漠化面积逐年加大，对电气化铁路绝缘影响愈发严重。研究沙尘环境对接触网绝缘子电场分布的影响，可为给该环境下接触网绝缘子污闪研究提供理论依据。首先，建立沙尘环境下接触网绝缘子电场分布的电磁场数学模型，构建边界条件，并转化为相应的有限元数学模型。其次，建立沙尘环境下接触网绝缘子的三维几何模型，根据模型内实体大小比例悬殊、网格和计算困难的特点，对模型进行合理的简化，提高仿真效率，提出沙尘环境下接触网绝缘子的几何建模方法。再次，通过有限元法计算得出不同环境因素影响下接触网绝缘子电场分布的特性规律，从而得出沙尘环境下的污闪特性。在实验室建立沙尘环境下的接触网绝缘子电场分布测量系统，测量绝缘子电场分布，验证计算结果。最后，总结得出沙尘天气导致接触网绝缘子闪络的电场强度及染污程度预警值。并针对接触网绝缘子设计及运营维护方面，提出绝缘子在沙尘环境下的有效监测方案。

我国西部地区沙漠化程度严重，随着铁路里程在西部的逐年增加，沙尘天气对电气化铁路接触网的影响也日益凸显。大量沙尘附着在接触网绝缘子表面，导致其表面污秽度急剧上升，在特定的条件下容易引发绝缘子闪络。“沙闪”作为一种特殊形式的污闪，已经成为影响我国西部电气化铁路正常运行的因素之一，有必要对西部沙尘地区接触网绝缘子的污闪特性和在线监测技术进行研究。.课题组以沙尘地区电气化铁路实际应用的接触网绝缘子为研究对象，分析了风速、粒径、浓度对绝缘子表面积污量的影响。设计了一种新型接触网腕臂绝缘子，为沙尘环境下绝缘子的选型提供了参考。仿真对比平腕臂和斜腕臂绝缘子积污特性差异，研究了不同安装方式对绝缘子积污特性的影响。.通过建立接触网绝缘子电场计算模型，研究了绝缘子表面覆着沙粒时，沙粒的粒径、带电量、极性和覆着位置对电场分布的影响。研究了绝缘子表面出现干燥带时，干燥带宽度、位置、数量对绝缘子电场分布的影响。讨论了全尺寸模型下绝缘子的电场特性，同时对绝缘子电晕特性进行了分析。.项目设计了一套泄漏电流在线监测系统，分析污秽绝缘子泄漏电流时频特性，提取其特征量，建立绝缘子状态预测模型，将泄漏电流特征量与环境参数输入模型实现对接触网绝缘子污秽度的实时预测。同时建立绝缘子污秽等级和污闪概率预测模型，实现了接触网绝缘子和线路当月污闪概率预测。最后，利用逻辑决断图对几类绝缘子常见故障的维修策略进行了分析和研究，针对不同故障得出了相应的维修策略并提出了关于绝缘子维修管理工作的建议。.本课题组对西部沙尘地区电气化铁路接触网绝缘子污闪特性及在线监测技术的研究，既是对现有接触网绝缘子污闪特性研究的完善和发展，同时也是当前沙尘地区铁路运输生产实际中亟待解决的关键问题，具有十分重要的理论意义和工程实际价值。