Interface degradation between mandrel and sheath can cause a decrease in insulation performance and mechanical strength of composite insulators. In this study, the interface ageing properties of cycloaliphatic epoxy resin and silicone rubber composite insulator were compared. A water diffusion test was adopted to simulate the composite insulator ageing in a hot and humid environment. A four-electrode system was built to detect leakage current at different locations (mandrel, sheath and interface), which is an important basis for evaluating insulator performance. The ageing degree of insulator could be quantitatively characterised by leakage current change. It was found that the infiltrated moisture had a great effect on insulation performance. Based on the water absorption test result, the interface performance of two insulators was mainly influenced by their sheath sealing quality. As an auxiliary evaluation method, temperature rise during the test was recorded using an infrared camera. The experiment results showed that interface degradation was the main factor for the insulation performance decrease of silicone rubber composite insulators. However, insulation level reduction of the cycloaliphatic epoxy resin was caused by the wet sheath. In addition, a model for temperature rise of cycloaliphatic epoxy resin insulators was proposed based on good correspondence between sheath material and insulation. The model incorporated multiple processes such as ageing and heating of insulators, and it can predict the early temperature rise well.

中文翻译：

---

基于四电极体系和温升模型的脂环族环氧树脂与硅橡胶复合绝缘子界面研究

芯轴和护套之间的界面退化会导致复合绝缘子的绝缘性能和机械强度下降。本研究比较了脂环族环氧树脂和硅橡胶复合绝缘子的界面老化性能。采用水扩散试验模拟复合绝缘子在湿热环境下的老化。建立了四电极系统来检测不同位置（芯轴、护套和界面）的漏电流，这是评估绝缘子性能的重要依据。绝缘子的老化程度可以通过漏电流的变化来定量表征。研究发现，渗入的水分对绝缘性能影响很大。根据吸水率测试结果，两个绝缘子的界面性能主要受护套密封质量的影响。作为辅助评价方法，使用红外相机记录测试过程中的温升。实验结果表明，界面退化是硅橡胶复合绝缘子绝缘性能下降的主要因素。然而，脂环族环氧树脂的绝缘水平降低是由湿护套引起的。此外，基于护套材料与绝缘之间良好的对应关系，提出了脂环族环氧树脂绝缘子的温升模型。该模型综合了绝缘子老化、发热等多个过程，能够很好地预测早期温升。使用红外摄像机记录测试期间的温度升高。实验结果表明，界面退化是硅橡胶复合绝缘子绝缘性能下降的主要因素。然而，脂环族环氧树脂的绝缘水平降低是由湿护套引起的。此外，基于护套材料与绝缘之间良好的对应关系，提出了脂环族环氧树脂绝缘子的温升模型。该模型综合了绝缘子老化、发热等多个过程，能够很好地预测早期温升。使用红外摄像机记录测试期间的温度升高。实验结果表明，界面退化是硅橡胶复合绝缘子绝缘性能下降的主要因素。然而，脂环族环氧树脂的绝缘水平降低是由湿护套引起的。此外，基于护套材料与绝缘之间良好的对应关系，提出了脂环族环氧树脂绝缘子的温升模型。该模型综合了绝缘子老化、发热等多个过程，能够很好地预测早期温升。脂环族环氧树脂的绝缘水平降低是由护套潮湿引起的。此外，基于护套材料与绝缘之间良好的对应关系，提出了脂环族环氧树脂绝缘子的温升模型。该模型综合了绝缘子老化、发热等多个过程，能够很好地预测早期温升。脂环族环氧树脂的绝缘水平降低是由护套潮湿引起的。此外，基于护套材料与绝缘之间良好的对应关系，提出了脂环族环氧树脂绝缘子的温升模型。该模型综合了绝缘子老化、发热等多个过程，能够很好地预测早期温升。