摘要
以南方高湿度地区某500 k V交流线路复合绝缘子大面积发热事故为背景,选取7支绝缘子样品,测量表面灰密(non-soluble material deposit density,NSDD)/盐密(equivalent salt deposit density,ESDD)、憎水性;在高压试验大厅悬挂绝缘子进行加压试验,利用紫外仪和红外仪进行观察,研究绝缘子的发热特性;解剖绝缘子,结合X射线光电子能谱(X ray electron energy spectrum,XPS)分析材料的理化特性,排除局部放电造成端部异常温升的可能性;做硅橡胶和芯棒样品吸水性试验,分析老化绝缘子的受潮特性;测量受潮硅橡胶的介电常数和电阻率;基于有限元分析软件Ansoft对硅橡胶受潮后的绝缘子进行仿真,研究硅橡胶受潮对电场分布的影响。得出结论:运行一段时间后,交界面良好的绝缘子在硅橡胶受潮后电场分布改变,导致护套端部电场强度升高,从而导致局部的极化损耗增加,出现局部温升。增大的电场也会影响材料的微观结构,使得材料老化加速。最后,针对复合绝缘子受潮后温升,提出防范措施。
In view of phenomenon of abnormal temperature rise at high voltage（HV） end of 500 k V AC composite insulators widely found in southern wet area, seven insulators are selected as sample studied. Non-soluble material deposit density（NSDD）/ equivalent salt deposit density（ESDD） and static contact angel on sheath surface are measured. The insulators are suspended in HV testing hall while peak value of operating voltage are applied on HV ends of insulators. HV end parts of insulators are dissected, whose chemical and physical features are analyzed via X ray electron energy spectrum. Possibility of partial discharge is excluded. Water absorption experiments are conducted to analyze moisture features of silicone rubber. Then relative dielectric constant and conductivity of damp silicone rubber are measured. Electric field distribution along surface of damp sheath is calculated with finite element method software. After tests and analysis, it is concluded that silicone rubber of aged composite insulators are prone to be moistened, and change of dielectric constant and conductivity may lead to electric field rise near HV end of insulator and cause its higher dielectric loss and temperature rise. Besides, higher electric field would influence micro structure of materials, challenging insulator life. Finally, some measures taken to avoid abnormal temperature rise are presented.
出处
《电网技术》
EI
CSCD
北大核心
2016年第2期608-613,共6页
Power System Technology
基金
国家自然科学基金项目(51477072)~~
关键词
复合绝缘子
异常温升
受潮
电场畸变
极化损耗
composite insulator
abnormal temperature rise
water absorption
electric field distortion
polarization loss
