220kV电流互感器故障分析  

Analysis of 220 kV Current Transformer Fault

作　　者：刘晓波 李月文 陈志勇 苗宇 LIU Xiaobo;LI Yuewen;CHEN Zhiyong;MIAO Yu(Ulanqab Electric Power Bureau,Ulanqab 012000,China)

机构地区：[1]乌兰察布电业局,内蒙古乌兰察布012000

出　　处：《内蒙古电力技术》2021年第2期84-88,共5页Inner Mongolia Electric Power

摘　　要：某变电站一220 kV间隔U相电流互感器金属膨胀器发生异常顶起,通过油色谱分析,发现H2体积分数严重超标,CH4与CO体积分数与故障前相比明显增大,结合特征气体法与三比值法分析,认为电流互感器内部存在低能量放电,遂返厂进行诊断性试验。试验结果表明,绝缘电阻及电容量、介质损耗因数试验均合格,局部放电试验与油色谱分析数据异常,初步判定电流互感器器身内部存在绝缘缺陷。通过解体试验,确定了电流互感器故障原因为零屏铝箔开裂后边缘形成毛刺、尖角等不规则形状使该处场强畸变,导致运行过程中存在低能量放电,变压器油裂解产生气体,最终使金属膨胀器向上顶起。对电流互感器进行返修处理,重新包扎电流互感器一次绕组,试验合格后交付使用。The metal expander of 220 kV interval U phase current transformer in a substation jacks up abnormally.Through oil chromatography,it is found that the H2 content exceeds the standard seriously and the content of CH4 and CO increased significantly before the failure.Analyzing in combination of characteristic gas method and Three Ratio Method,it is suspected that there is low energy discharge inside so that it is returned to the factory for diagnostic test.The test results show that insulation resistance and capacitance and dielectric loss factor test are qualified but partial discharge test and oil chromatographic analysis data are abnormal.According to the preliminary judge,there are insulation defects inside.Through disintegration tests,it is identified that the fault cause of current transformer lies in strong distortion caused by irregular shapes such as burr and sharp angle formed on the edge after zero screen aluminum foil cracking,which causes low energy discharge during operation,causes the transformer oil to crack to produce the gas,and finally causes that the metal expander jacked up.After finding the cause,the fault phase current transformer is returned to factory for repair and the current transformer primary winding is re-wrapped.After the test is qualified,it will be delivered for use.

关 键 词：电流互感器 金属膨胀器 低能量放电 解体试验 零屏开裂 

分 类 号：TM452[电气工程—电器]