The Application of Wavelet in the Short-Term Flicker Severity Calculation

The short term flicker severity P_st is an important index of power quality in the standards of IEC. Usually Discrete Fourier Transform (DFT) is used to calculate P_st, due to the inherent spectral leakage and barrier effect of DFT lead to low accuracy of P_st, therefore a method to improve the accuracy of P_st is proposed in this paper, the corn of this method is that, using DFT and Discrete Fourier inverse transform (IDFT) overcomes the problem of frequency aliasing in the wavelet transform (WT), and applying WT extracts voltage fluctuations signals in order to get accurate frequency and amplitude information, thereby improving the accuracy of P_st. The simulation experiments show that the method is effective.