A new method with high accuracy for electrical harmonic estimation based on CZT
Yang Luo · Advanced Technology of Electrical Engineering and Energy · 2012
A new method with high accuracy for electrical harmonic estimation based on CZT(Chirp z-transform) is presented in this paper.First,using the characteristic that CZT can realise frequency spectrum refinement,the phasor of the power system fundamental frequency signals is extracted from the multifrequency signals.After subtracting the system fundamental frequency signal from the multifrequency signals,the surplus signal is truncated with the five term Rife-Vincent window and its spectrums are calculated by FFT.Finally,according to the power system fundamental frequency,each harmonic frequency is calculated.And then the Rife-Vincent window is interpolated in the frequency domain.The results of experiments show that the five term Rife-Vincent window has a better curb ability to the spectral leakage.And in the non-coherent sampling conditions,the proposed method almost has the same estimation accuracy with the method which is based on multipoint interpolation FFT through analysing the 30 order harmonics,but the new method only costs about half computation times.