西南湿润雾霾环境中硅橡胶材料电晕老化特性与机理研究

With the application of silicone rubber composite insulator in power system, the reliability of the composite insulator has been widely concerned. S.M. Gubanski said that Despite of decades of lasting development, some issues related to the performance of this material in various working conditions still remain to be resolved, including an understanding of the impact of corona discharges on the material deterioration. In HV overhead lines,corona could occur even on well designed transmission line hardware and insulators especially under wet condition. Corona will significantly damage the silicone rubber insulators and affect its long-term operating performance.The project combines haze, high temperature and high humidity of the unique weather characteristics of southwest of China, the research in harsh operating conditions silicon rubber insulation aging properties was carried out. Through laboratory simulation operation conditions on site, the different factors such as different smog ingredients, ambient temperature, humidity, voltage type and aging time on the effects of silicone rubber insulation aging properties of Corona were studied. Use of space charge measurement with the method of combining several test methods to assess the ageing of silicone rubber. The physical-mathematical model and numerical simulation of corona discharge in established wet haze was studied as well as the corona aging differences of silicone rubber material under wet haze or clean and dry condtion.Then the corona aging mechanism of silicone insulating material under wet haze conditon was obtained.

随着硅橡胶复合绝缘子的大量应用，其可靠性得到广泛的关注。国际知名专家IEEE Fellow S.M. Gubanki指出：经过多年的研究，一些与硅橡胶绝缘材料性能相关的问题仍有待解决，其中就包括电晕放电对硅橡胶绝缘材料老化性能的影响。在潮湿条件下运行的高压输电线路，即使是经过精心设计的绝缘子和与之相连的金具都无法避免电晕的产生，持续的电晕会明显的损伤硅橡胶绝缘子并影响其性能。本项目结合我国西南地区湿润雾霾和高温的气候特点，研究恶劣运行条件下硅橡胶绝缘材料的电晕老化特性。通过拟现场的运行条件，研究不同雾霾成分、环境温度、环境湿度等因素对硅橡胶材料的电晕老化特性的影响；利用空间电荷的测量与多种测试手段相结合的方法对硅橡胶的老化状态进行评估；建立湿润雾霾中电晕放电的物理数学模型并进行数值仿真，研究湿润雾霾条件与干燥清洁下硅橡胶材料老化行为的差异，揭示湿润雾霾条件下硅橡胶绝缘材料的老化机理。

西南地区是我国清洁能源基地和“西电东送”工程的起点，区域里的高压电气设备众多，由于硅橡胶材料具有较强的憎水性和憎水性迁移特性，能有效的提高沿面闪络电压，具有良好的外绝缘特性，常用作高压电气设备的外绝缘材料。但由于恶劣的自然环境条件，硅橡胶材料易产生老化现象，电气性能降低，严重时导致绝缘失效，造成外绝缘事故。本项目针对我国西南地区气候特点，搭建了人工模拟雾霾环境试验平台，探索了一种利用高速气流分散粉末模拟雾霾的方法，系统研究了湿度、雾霾、积污等多种恶劣复杂环境对硅橡胶绝缘材料的电晕老化特性的影响规律，并结合憎水性、傅里叶红外光谱、闪络电压等多种测试结果对硅橡胶的老化状态进行综合评估，最后建立了电晕放电的数值仿真模型，探讨了雾霾条件下硅橡胶材料的电晕老化机理。本项目的研究结果可为电气设备外绝缘用硅橡胶的性能优化与改进，以及电气设备的运行和维护提供一定的参考。本项目的研究成果如下：.①电晕老化对硅橡胶的劣化作用是非常显著的，硅橡胶材料老化的宏观状态表现出裂纹，憎水性明显降低，微观结构出现一定程度的变化，但均发生再硅橡胶材料的表层，核磁共振的测试结果表明电晕放电将对硅橡胶产生不可恢复的劣化，硅橡胶材料表面严重覆污时，污秽物质可在一定程度上阻挡电晕放电对硅橡胶的损伤，高温硫化硅橡胶样品的抗电晕老化性能优于普通硅橡胶，因此可以优化硅橡胶填料成分，以提高其抗电晕老化性能。.②基于硅橡胶表面宏观状态、内部微观状态和电气性能状态，提出了基于模糊和证据推理融合方法的硅橡胶材料电晕老化状态评估模型，模型评估的准确率大于90%。.③建立了针-板电极的电晕放电数值仿真模型，在电场作用下带电荷的悬浮气溶胶颗粒不仅影响电晕放电过程和放电的能量，同时易吸附于材料表面，增加材料的表面电荷，更易于导致Si-CH3断裂。雾霾条件下，硅橡胶表面形成硝酸盐、硫酸盐和铵盐等，极易对硅橡胶表面产生腐蚀劣化。