The Research Of Voltage Fluctuations And Flicker Detection Based On Interpolation FFT Algorithms

Interpolation algorithm is applied to modify the results of FFT and propose the interpolation FFT algorithm (IFFT) to improve the accuracy of spectral analysis.The short term flicker value Pst is an important index of voltage fluctuations and flicker, two important parts are included in calculating the short term flicker value Pst, which are extracting voltage fluctuations and flicker signal envelope and analyzing the extraction voltage fluctuations and flicker signals. The extraction of the envelope of voltage fluctuations and flicker signal is the premise to calculating the short-term flicker value Pst, but the analysis of voltage fluctuations and flicker signal has some problems. Generally, FFT is used to analyze the extraction voltage fluctuations and flicker signals, however, FFT has the shortcoming of spectral leakage and fence effect, which will lead to the calculation accuracy of the short-term flicker value Ps, is not high.least square method algorithm is used to model the mapping of frequency and sin voltage corresponding frequency at unit instant flicker value。 At caculating short-time flicker value Pst, the Mapping of frequency and sin voltage corresponding frequency at unit instant flicker value must be modeled, Because, a finite number of discrete frequency corresponding to sinusoidal voltage fluctuation value are given in IEC standards。Simulation test show that the caculating accuracy of short-time flicker value Pst can be improved remarkably, and can meet the need of practical engineering.Final, hardware and software of the device of voltage fluctuations and flicker detection is designed carefully.