外绝缘用液体硅橡胶老化现象的微观表征

摘要

In recent years, some composite hollow core insulators of current transformers used in China Southern Power Grid have showed different levels of aging and cracking. In this paper, some tests and experiments, including SEM, FTIR and TG analysis, have been done on the aged silicone rubber. It is found that the upper surface of the housing and sheds suffer from more serious degradation than the lower surface. Also, it is found that the structure and functional groups of the aged surface have changed a lot and crystal structure is observed, which may lead to the loss of hydrophobicity and the degradation of tracking performance.%本文针对近年来出现在一些变电站SF6电压、电流互感器的液体硅橡胶绝缘护套出现龟裂老化这一现象，对发生老化的硅橡胶材料进行了性能测试和试验，并利用红外光谱分析、XPS分析、热失重等手段分析了其微观结构和物质组成的变化。研究发现老化后的液体硅橡胶中Si-C、Si-O官能团和Si、C、O元素的相对含量发生了变化，且随着老化程度的增加呈现出较为明显的规律，老化越严重，Si-C键含量越少，C元素的含量越少，O元素含量越多。本文认为，用官能团含量、元素相对含量可以准确地表征液体硅橡胶材料的老化程度。通过对不同老化程度的液体硅橡胶进行的憎水性、耐漏电起痕性能的试验也证实了本文的观点。