一起220 kV主变压器有载分接开关触头烧损缺陷分析

Analysis of Burning Damage Defects of Contacts of On-load Tap-changer in 220 kV Main Transformer

文中分析了一起有载分接开关触头在220 kV主变压器有载分接开关深度检修中首次报告烧损的缺陷。该有载分接开关经过试验和现场吊芯检查后,发现奇数侧主动触头组的A相触头发黑变色,转轴烧结失去功能。经分析奇数侧触头组的转轴接触电阻异常增大导致的过热为开关触头烧损的直接原因。根据缺陷产生机理分析,文中对有载分接开关日常运维提出了针对性建议,为后续类似工作处置提供了宝贵经验。

The defects of burning damage are analyzed, which are reported for the first time in an in-depth maintenance of on-load tap-changer in a 220 kV main transformer. After electrical test and hanging-core inspection, it is found that the contacts in phase A of odd-numbered active contact group turns black, and the rotating shaft is sintered and loses its function. The overheating caused by the abnormal increase of contact resistance of rotating shaft of contact group in odd-numbered side directly leads to burning damage of the contacts. The cor responding suggestions for daily operation and maintenance of on-load tap-changers are put forward, which provides precious experiences for the follow-up similar works.