220 kV电流互感器油中溶解气体异常故障分析

Fault Analysis on Abnormal Dissolved Gas of a 220 kV Current Transformer

以220 kV油浸式电流互感器为研究对象,对一起油中溶解气体数据异常导致停运事件进行了故障分析。故障特征表现为油中溶解气体氢气、乙炔和总烃远超标准值,经测试绝缘电阻、介质损耗因数和电容量均正常。对设备解体发现绝缘层存在褶皱和积碳,电容屏出现断裂和X蜡。分析认为由于绕组制造工艺不良,绑扎不紧实导致绝缘层褶皱和电容屏断裂,形成绝缘薄弱点,引起局部放电和过热,导致油中溶解气体超标。

In this paper,the 220 kV oil-immersed current transformer is taken as the research object,and the fault analysis of a shutdown event caused by abnormal dissolved gas analysis data is carried out.The fault shows that hydrogen,acetylene and total hydrocarbon dissolved in the oil seriously exceeded standard value.After testing,the insulation resistance,dielectric loss factor and capacitance were all normal.Through the equipment disintegration,it was found that there were wrinkles and carbon deposition in the insulation layer,and there were cracks and X wax in the capacitance plates.The analysis shows that due to the poor manufacturing process and loose binding of the winding,the insulation layer was wrinkled and the capacitance plates were broken,forming weak points of the current transformer,which caused partial discharge and overheating,and resulted in excessive dissolved gas in the oil.