Abstract: High current will impact the winding on the low-voltage side of the main transformer. This paper proposes an analysis method of low-voltage side impact current of the main transformer based on the wave recording file. This method only needs to configure a few parameters to analyze the current impact on the low-voltage side of the wave recording file. By recording the relevant information of each impact, a database of high current impact on the main transformer is established to understand the impact situation in the life cycle of the main transformer.