The abnormal temperature rise of glass fibre reinforced polymer (GRP) composite in the composite insulator, which has been reported as the early stage of decay-like fractures, has gained significant attention from both industrial and academic sectors. In this study, GRP rod samples, obtained from composite insulators were subjected to hygrothermal ageing and were tested under the conditions according to IEC 62217. The leakage current, partial discharge and temperature rise of the samples were measured. All three parameters tended to increase with the ageing time under AC and DC electric fields. The power contribution supplied by partial discharge could be ignored. Simulation results proved that the temperature rise was mainly caused by the volume current. Under the DC electric field, the conductive current was the heating source, whereas under the AC electric field, the heating power was supplied by both conductive current and the polarisation loss. The content of absorbed moisture in the GRP rod sample showed a linear relationship with the temperature rise. The moisture absorption property can be used as an index to evaluate the ageing state of GRP rod in the composite insulator.

中文翻译：

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湿热老化后交直流电场作用下玻璃纤维增​​强聚合物的热源

据报道，复合绝缘子中玻璃纤维增​​强聚合物（GRP）复合材料的异常温升已被视为腐烂性断裂的早期阶段，引起了工业界和学术界的广泛关注。在这项研究中，将从复合绝缘子获得的GRP棒样品进行湿热老化，并在符合IEC 62217的条件下进行测试。测量了样品的泄漏电流，局部放电和温度升高。在交流和直流电场下，这三个参数都随着老化时间的增加而增加。由局部放电提供的功率贡献可以忽略。仿真结果表明，温升主要是由体积电流引起的。在直流电场下，导电电流是热源，而在交流电场下，通过传导电流和极化损耗来提供加热功率。玻璃钢棒样品中吸收的水分含量与温度升高呈线性关系。吸湿性可以用作评价复合绝缘子中的GRP棒的老化状态的指标。