Fault Analysis and Location of the Main Transformer in UHV Substation

UHV AC transformer is an important equipment in 1000kV UHV substation, and its importance is self-evident. In this paper, the characteristics of fault current in UHV main transformer are analyzed combined with the UHV main transformer trip event caused by abnormal discharge of a combined electric appliance. And the transformer fault recorder is used to realize the quick location of main transformer by phase difference. According to the analysis results, it was determined that the primary fault point was in the B phase gas chamber of 50121 switch on the 500kV side. The gas component test results on site were consistent with the analysis results, which verified the effectiveness of the fault location method.