Study on Nanosecond Impulse Frequency Response for Detecting Transformer Winding Deformation Based on Morlet Wavelet Transform

摘要

A large amount of studies has shown that compared with sweep frequency response analysis (SFRA), impulse frequency response analysis (IFRA) is feasible for online condition monitoring of power transformer winding deformation and can increase the frequency range of analysis. At present, the frequency response curves of off-line IFRA methods are mostly solved by Fast Fourier Transform (FFT). In this paper, IFRA for detecting transformer winding deformation based on morlet wavelet transform is presented. The deformation of the winding is detected by calculating the offset between the resonance point of the frequency response curve and the anti-resonance point instead of the correlation coefficient between the frequency response curves. Three levels of axial winding deformation are simulated in a 10kV distribution transformer. The IFRA method is solved using FFT and Morlet wavelet transform, respectively, and the winding is determined by calculating the offset of the resonance points of the frequency response curve. The reliability and sensitivity of the IFRA method based on the Morlet wavelet transform are verified, and the repetitive verification is performed.