A High Accuracy Detection Method of Voltage Flicker Signal Based on Time-Frequency Transform

High-accuracy and fast detection of voltage fluctuation and flicker is the basis of analyzing the flicker event and controlling its hazards. Here, a new method based on the Blackman-windowed short time Fourier transform (B-STFT) is proposed for the detection of voltage flicker signal. Extracting the rated frequency spectra achieved from the B-STFT amplitude matrix of the analyzed flicker signal, the flicker envelop, the magnitude of the carrier signal fundamental frequency component and the modulator signal can be detected. This method is not only suited for the detection of the stationary flicker but also suited for the detection of the short-time and time-varying flicker signal. It can handle the harmonic-carrier flicker as well as the fundamental-carrier flicker. The simulation results show that the detection accuracy is in high precision and effectiveness, and the method is immune against noise and the fluctuation of power frequency as well.