摘要
为分析和诊断两例±500k V干式SF6气体绝缘换流变压器阀侧套管内部放电故障,对放电前后套管绝缘特征量和解体后内部特征进行了测试和检查;通过模拟故障套管运行环温和加载特征谐波电流损耗,对套管载流导电管和绝缘子外套温度分布规律进行有限元仿真计算;故障套管直流电阻值、SF6分解物含量、温度计算结果、解体后内部过热和放电痕迹表明：伊敏、宝鸡换流站两例套管放电故障均由载流导电管铜铝过渡接触电阻异常发热,尼龙导向锥过热分解物污染套管SF6/环氧树脂界面绝缘所致。依据IEC标准规定的套管热点温度要求和故障套管温度场计算结果,提出了绝缘子外套最热点温度与环境温度差为25℃的内部发热缺陷诊断准则,通过第3例同型号异常发热缺陷套管对诊断准则进行了验证。对75支同型号套管利用研制的缺陷套管现场修复装置在不移动换流变和不整体拔出缺陷套管的前提下完成了现场修复。研究结果可为SF6气体绝缘高压套管内部发热缺陷诊断和处理提供方法和依据。
In order to analyze and diagnose internal discharge failure of two ± 500 k V SF6 gas-insulated valve side bushings in converter transformers, insulation characteristics before and after the discharge and internal characteristics after disassembly are tested and checked. Temperature distribution of current-carrying conductor and insulator are simulated with finite element method. DC resistance of conductor, content of SF6 decomposition products, temperature calculation results, overheating and discharge traces show thatbushing discharge failures in Yimin and Baoji convertor station are caused by contact resistance abnormal heating of transitional copper-aluminum contact in conductive tube and contamination of nylon guide cone decomposition along SF6/epoxy insulation interface. According to IEC hottest spot temperature standard and fault bushing temperature field calculation results, a new diagnostic criteria of internal heating defects with temperature difference of 25 ℃ between the hottest point and ambient temperature are put forward. And this method is verified by a bushing of the same type with abnormal thermal defect. 75 bushings of the sametype are repaired on-site without shifting converter transformers and removing the defective bushings. The results provide a method and basis for diagnosis and management of heating defects in SF6 gas-insulated high voltage bushings.
作者
周安春
高理迎
冀肖彤
张民
汤浩
ZHOU Anchun;GAO Liying;JI Xiaotong;ZHANG Min;TANG Hao(State Grid Corporation of China, Xicheng District, Beijing 100031, China;China Electric Power Research Institute, Haidian District, Beijing 100192, China)
出处
《电网技术》
EI
CSCD
北大核心
2018年第5期1401-1409,共9页
Power System Technology
基金
国家电网公司科技项目(GYB17201400058)~~
关键词
SF6气体绝缘
换流变压器阀侧套管
套管放电故障
电流致热
现场修复
SF6 gas insulation
converter transformer valve-side bushing
bushing discharge failure
current overheating
field repair
