A method of voltage flicker estimation based on interharmonic pairs

This paper proposed a new method to estimate voltage flicker using the discrete Fourier transform (DFT). Based on the specified signal processing recommendations by IEC61000-4-7, the proposed method obtains the amplitude, frequency and phase angle of each harmonic/interharmonic using the odd points interpolation correction method. According to the electric power distortion component symbiosis mechanism, the detected interharmonics in pairs are transformed into a flicker signal. Combined with the double-side property, the interharmonics in pairs can be extracted. The parameters of flicker signal are obtained by the signal transform equations. The simulation results indicate that it is easy and quick to estimate the parameters by detecting the interharmonics signal directly and estimating the flicker signal indirectly; and the odd points interpolation correction method can separate harmonics from interharmonics effectively, and strongly restrain the spectral interruption.