电网技术2018，Vol.42Issue(5)：1401-1409,9.DOI:10.13335/j.1000-3673.pst.2018.0219
干式SF6气体绝缘换流变压器阀侧套管电流致热型放电故障分析及现场修复
Analysis and Field-Repair of Current Overheating Faults on Dry Type SF6 Gas-Insulated Valve Side Bushing in Converter Transformer
摘要
Abstract
In order to analyze and diagnose internal discharge failure of two ± 500kV 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.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Key words
SF6 gas insulation/converter transformer valve-side bushing/bushing discharge failure/current overheating/field repair分类
信息技术与安全科学引用本文复制引用
周安春,高理迎,冀肖彤,张民,汤浩..干式SF6气体绝缘换流变压器阀侧套管电流致热型放电故障分析及现场修复[J].电网技术,2018,42(5):1401-1409,9.基金项目
国家电网公司科技项目(GYB17201400058).Project Supported by Science and Technology Project of SGCC(GYB17201400058). （GYB17201400058）
