动态载荷下复合空心绝缘子连接界面疲劳失效机理研究

Hollow composite insulator are usually made of FRP, flange and silicon rubber sheds. As an important component of UHV ac/dc equipment, such as wall bushing, dc circuit breaker, disconnecting switch, dc voltage divider, arrester and so on, mainly undertake machinery, sealing, insulation coordination inside and outside. Along with the development of the UHV projects in China, the failure on the interface of flange and FRP tube has appeared several times, which led to the decrease of the equipment and mechanical properties of the interface, SF6 gas leakage, and even breakdown discharge failure. Therefore, the higher reliability of the interface and connection of the hollow core insulators is required because of the safe and stable operation of UHV equipment. So the research on failure mechanism of the interface and connection is also required urgently. This project focuses on the interface and connection between FRP tube and flange of the hollow core insulators. Researches are carried out on the damage rule of the interface under different load (tensile and shear), which reveals the relationship the interface microstructure and fatigue failure load, and the relationship of curing temperature of the glue and the connection interface strength. The objective of the study can not only reveal the hollow composite insulator interface connection failure mechanism of the structure, but also can improve the design method and reliability of the equipment, which not only be an important theoretical value, but also an important practical significance.

空心复合绝缘子通常由玻璃钢筒、法兰金具和硅橡胶伞裙等三部分组成，一般作为特高压交直流设备的重要组成部件，主要承担机械、密封及内外绝缘配合等作用。随着中国特高压工程的发展，换流站/变电站设备已多次出现因空心复合绝缘子玻璃钢筒和法兰金具连接界面失效导致的设备机械性能下降、SF6气体泄漏，甚至击穿放电等故障。因此，特高压设备的安全稳定运行对空心复合绝缘子连接界面的可靠性提出了更高的要求，亟需开展空心复合绝缘子界面连接结构的失效机理研究。本项目主要针对空心复合绝缘子玻璃钢筒-法兰金具连接界面，研究不同载荷作用下，界面连接结构的疲劳破坏规律，揭示疲劳失效界面微观形貌和载荷的关系；研究界面表面处理对连接界面抗疲劳失效的影响；研究胶黏剂固化温度和连接界面强度的关系。本项目的研究不但能够揭示空心复合绝缘子界面连接结构的失效机理，而且能够提高设备的设计可靠性，既具有重要的理论价值，又有重大的实际意义。

近年来，变电设备多次出现因空心复合绝缘子端部连接结构动态失效导致的机械和电气故障。本项目以直流穿墙套管用500kV长悬臂空心复合绝缘子作为主要研究对象，分别对间隙结构和过盈结构产品的间隙或过盈量、胶装比、温度特性、不同负荷下的应力分布、损伤演化进行了仿真计算研究和试验研究，分析了交变载荷下，空心复合绝缘子端部连接结构的疲劳破坏规律，法兰金属表面处理方法对粘接界面抗疲劳性能和失效形式的影响，及不同温度下粘接结构和粘接强度的疲劳特性。本项目首次设计了空心复合绝缘子的疲劳特性试验，揭示了不同连接界面结构空心复合绝缘子的失效规律，并开发优化了新型的空心复合绝缘子结构，在直流直流工程中得到推广应用。