广东地区高温发热线路棒形复合绝缘子劣化特性

为了揭示高温发热的线路棒形复合绝缘子的劣化特性,文中对广东电网江门供电局某220 kV故障绝缘子开展了研究。观察了该支绝缘子的外观形貌,在带电状态下进行红外、紫外检测。之后进行解剖观察,采用现代材料测试方法(SEM、XPS)对比了芯棒劣化处与正常处的材料特性,使用宽频介电谱仪对比测试了劣化处与正常处芯棒短样的电气参数。试验和解剖结果发现,该绝缘子护套表面有击穿孔,加压温升严重、外部有微弱放电。内部交界面处芯棒表面劣化已经从高压端延伸至中部。材料分析表明界面处芯棒受到了严重的放电破坏,环氧树脂发生裂解,玻璃纤维有断裂和蚀损现象,存在氧化分解、酸性液体侵蚀等劣化过程。此外,劣化处芯棒的介电常数、介损角正切、电导率都有了明显的上升,造成电场进一步产生畸变,局部放电过程增强。研究表明,该类高温发热的线路棒形复合绝缘子芯棒劣化严重,并且局部放电等劣化过程较为剧烈,断裂风险极大。

Deterioration Characteristics of Rod Type Composite Insulators in Guangdong High Temperature Heating Line

In order to reveal the deterioration characteristics of the high temperature heating line rod composite insulators,this paper has carried out a study on a 220 kV fault insulator of the Jiangmen Power Supply Bureau of Guangdong power grid.The appearance of the insulators was observed and the infrared and ultraviolet detection was carried out under the charged state.Then the anatomical observation was carried out.The material characteristics of the core rod deterioration and normal location were compared with modern material testing method(SEM and XPS).The electrical parameters of the short rod of the deteriorating part and the normal mandrel were compared with the broadband dielectric spectrometer.The experimental and anatomical results show that the surface of the insulator is perforated,the pressure temperature rises seriously,and the external discharge is weak.The surface degradation of the mandrel at the internal interface has been extended from the high pressure end to the middle.The material analysis shows that the core rod at the interface is seriously damaged by electric discharge.The epoxy resin is cracked,and the glass fiber is cracked and eroded.There are deterioration processes such as oxidative decomposition and acid liquid erosion.In addition,the dielectric constant,dielectric loss tangent and electrical conductivity of the core rod increased significantly,resulting in further distortion of the electric field and enhanced partial discharge.The research shows that the core rod of the high temperature heating line composite insulator is deteriorated seriously,and the partial discharge and other deterioration processes are more severe,and the risk of fracture is great.