500kV输电线路在运复合绝缘子典型缺陷及分析

Typical Defects and Analysis of Composite Insulators Served in 500 kV Transmission Lines

500 kV输电线路复合绝缘子运行10年以上,出现伞裙粉化、对折开裂、异常发热等缺陷。为了分析其中的原因,对故障绝缘子进行外观检查、红外测温、额定拉力试验、硬度测试、机械性能测量、傅里叶红外光谱分析、X射线光电子能谱分析、解剖试验,结果表明500 kV输电线路复合绝缘子在户外环境里长期运行,受到电、光、热、污秽等因素的影响,绝缘子伞裙表面污秽受潮放电,导线电晕放电等将产生高能带电粒子,在放电产生的带电粒子及太阳紫外光子的作用下,硅橡胶材料分子中的Si-O-Si主链和Si-CH3侧链将发生断链,引发硅橡胶性能劣化,表现为粉化、劣化现象;对故障绝缘子发热部位进行解剖,芯棒表面明显酥朽,芯棒缺陷处的玻璃纤维明显裸露,表面存在一定的蚀损痕迹,环氧树脂严重缺损,颜色呈现棕黄色,结合芯棒解剖结果分析异常温升是由于芯棒酥朽老化引起的局部放电等过程产生。

The composite insulators of 500 kV transmission line have been running for more than 10 years,and there are defects such as pulverized sheds,splitting cracking,abnormal heating and so on. In order to analyze the reasons,the visual inspection of fault insulators、infrared temperature measurement、rated tensile test、hardness test、mechanical property measurement、Fourier infrared spectroscopy、X-ray photoelectron spectroscopy、anatomical test were carried out. The results show that the composite insulator of500 kV transmission line runs for a long time in the outdoor environment was affected by factors such as electricity、light、heat、and pollution. The surface of the shed is polluted by moisture,and the corona discharge of the wire will produce high-energy charged particles. Under the action of charged particles and solar ultraviolet photons generated by discharge,the Si-O-Si backbone and the Si-CH3 side chain in the molecule of the silicone rubber material will be broken. The performance of silicone rubber is deteriorated,which is characterized by pulverization and deterioration. The heating part of the faulty insulator was dissected,the surface of the mandrel was obviously rotten and the fiberglass at the defect of the mandrel was obviously bare. There was a certain trace of corrosion on the surface. The epoxy resin was seriously defected;Color is brownish yellow. Combined with the anatomical results of the mandrel,the abnormal temperature rise is due to the partial discharge caused by the aging of the mandrel.