Aiming at the analysis of power quality perturbation

a kind of power quality analysis method based on the combination of improved EMD denoising and S-transform is proposed. The obtained signal is decomposed by EMD and the IMF component of high-frequency signal is selected for wavelet threshold denoising. The IMF component of high-frequency signal and the original signal are reconstructed in sequence. The reconstructed signal is processed by S-transform so to extract the characteristics of power quality perturbation. The specific power quality perturbation is analyzed in accordance with such characteristics as time

frequency and amplitude of S-transform

and the perturbation time and type are judged. The simulation results show that the combination of improved EMD denoising and S-transform can effectively remove the noise component in the signal and improve the accuracy of power quality perturbation analysis under noise interference.