特高压换流变阀侧油浸表带触指劣化失效机制  

Failure Mechanism of Oil-immersed Louver Contacts in the UHV Converter Valve

作　　者：黄志成 刘凡 涂彦明 胡仕红 刘凯[3] 吴广宁[3] HUANG Zhicheng;LIU Fan;TU Yanming;HU Shihong;LIU Kai;WU Guangning(Electric Power Science Research Institute of Sichuan Electric Power Company,Chengdu 611730,China;Power Internet of Things Key Laboratory of Sichuan Province,Chengdu 611730,China;School of Electrical Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]四川省电力公司电力科学研究院,成都611730 [2]电力物联网四川省重点实验室,成都611730 [3]西南交通大学电气工程学院,成都610031

出　　处：《高电压技术》2024年第9期4120-4130,共11页High Voltage Engineering

基　　金：国网四川省电力公司科技项目(52199723000G)。

摘　　要：油浸表带触指作为特高压换流变阀侧升高座区域绕组引出线与套管的关键载流连接件,其过热失效导致的阀侧直阻超标构成了电力系统的严重安全隐患。为此基于油浸表带触指的劣化分布特征,明确了引发其过热失效的外部原因;通过扫描电镜、能量色散光谱、X射线衍射、电感耦合等离子体及模拟试验等手段,探究了油浸表带触指的劣化失效机制。结果表明:不对中引起的表带触指压力不均导致部分触指片过流并引发局部高温;高温环境下,镀银铜触指片发生孔蚀,铜基底通过微孔与银镀层、绝缘油构成银铜原电池,生成腐蚀性硫银-油与铜-油配合物、铜银硫矿及硫化亚铜等产物,造成触指片银镀层破坏、粘附性降低、接触电阻增大;电接触区域的磨损以及高温下不锈钢骨架的塑性变形则加速了表带触指的劣化。该研究结论可为油浸电接触部件设计、故障分析和进一步研究提供参考。Oil-immersed louver contacts,as a key current-carrying connection component for the lead-out wire and bushing in the elevated seat area of the ultra-high voltage converter valve,plays a crucial role.The overheat failure of the louver contacts on the valve side,leading to excessive direct resistance,constitutes a serious safety hazard in the power system.Based on the degradation distribution characteristics of the louver contacts,this paper clarifies the external causes that trigger its overheat failure.Through scanning electron microscopy,energy-dispersive X-ray spectroscopy,X-ray dif-fraction,inductively coupled plasma,and simulated experiments,the degradation failure mechanism of the oil-immersed louver contacts is explored.The results indicate that uneven pressure on the louver contacts caused by misalignment leads to overcurrent in some finger segments of louver contacts,resulting in local high temperature.Under high-temperature conditions,silver-plated copper finger segments undergo pitting corrosion,and the copper substrate forms a silver-copper primary cell with the silver plating and insulating oil,generating corrosive silver-sulfide-oil and copper-sulfide-oil com-pounds,as well as copper-silver sulfide and cuprous sulfide.This process leads to the destruction of the silver plating,reduced adhesion,and increased contact resistance of the finger segments.Wear in the electrical contact area and plastic deformation of the stainless-steel framework at high temperatures further accelerate the degradation of the louver contacts.The research conclusions can serve as a reference for the design,fault analysis,and further study of oil-immersed electri-cal contact components.

关 键 词：油浸表带触指 孔蚀 塑性变形 磨损 硫化亚铜 

分 类 号：TM721.1[电气工程—电力系统及自动化]