Analysis of Differential Misoperation of Main Transformer Caused by Abnormal Transmission Characteristics of Merged Units
The article starts with the misoperation and tripping event of the main transformer caused by abnormal transmission characteristics of the low-voltage side merging unit during a 10 kV line fault in an intelligent substation.It elaborates on the event process and protection action analysis.Using waveform sampling data during the fault,starting from differential current calculation and action criteria,the article analyzes the reasons for the abnormal action of the main transformer differential protection.Explored the manifestation and causes of phase anomalies in the transmission characteristics of the merged unit,and proposed corresponding preventive measures and suggestions to reduce the risk of misoperation caused by such faults.