硅橡胶和脂环族环氧树脂复合绝缘子界面的水煮老化特性

Hydrothermal Aging Characteristics of Silicone Rubber and Cycloaliphatic Epoxy Resin Composite Insulators Interface

复合绝缘子是常用的输电线路绝缘器件,良好的芯棒-护套界面是复合绝缘子安全稳定运行的前提。水煮老化后测量泄漏电流是评价硅橡胶绝缘子界面性能的有效方法,在此基础上采用四电极装置将硅橡胶和脂环族环氧树脂绝缘子样品的护套、界面和芯棒处的泄漏电流分开进行了测量和比较。猜想并验证了影响绝缘子水煮老化表现的主要因素——水分,进一步地,比较了硅橡胶和脂环族环氧树脂复合绝缘子的吸水性。结果表明:水煮老化过程中,硅橡胶样品界面电流增加明显,而环氧树脂样品主要增大的是护套电流,界面电流增加迟缓;绝缘子护套材料的水分扩散系数越大,水分越容易进入界面,界面绝缘性能下降越明显,选用扩散系数小的护套可以有效地改善绝缘子界面性能。

Composite insulators are commonly used in transmission line insulating devices, and a good core-sheath interface is the prerequisite for safe and stable operation of composite insulators. Measuring the leakage current after boiling and aging is an effective method to evaluate the interface performance of silicone rubber insulators. On this basis, a four-electrode device is used to measure and compare the leakage currents at the sheath, interface, and core of the silicone rubber and cycloaliphatic epoxy insulator samples. The main factor affecting the aging performance of insulators is verified to be moisture. Furthermore, the water absorption of silicone rubber and cycloaliphatic epoxy resin composite insulators is compared. The results show that, during a boiling aging process, the interface current of the silicone rubber samples increases significantly, while the sheath current of the epoxy resin samples is mainly increased, and the interface current increases slowly. The greater the moisture diffusion coefficient of the insulator sheath material is, the more easily the moisture enters the interface, and the more obvious the degradation of the interface insulation performance is. Selecting a sheath with a small diffusion coefficient can effectively improve the interface performance of the insulator.