Application of soft-threshold wavelet de-noising method in the diagnosis of transformer during impulse test

In this paper, neutral point current data during transformer impulse tests are analyzed by soft-threshold shrinkage de-noising method based on wavelet frame. Simulation tests are made to verify that the partial features of the original signal can be reserved after de-noising. The simulation results show that this de-noising method is applicable to processing the oscillating signal that damps quickly. In addition, it is verified that the conflicts between de-noising and reserving the signal's partial features can be solved by this method.