A novel power harmonic analysis method based on Nuttall-Kaiser combination window double spectrum interpolated FFT algorithm

Abstract

Harmonics pose a great threat to safe and economical operation of power grids. Therefore, it is critical to detect harmonic parameters accurately to design harmonic compensation equipment. The fast Fourier transform (FFT) is widely used for electrical popular power harmonics analysis. However, the barrier effect produced by the algorithm itself and spectrum leakage caused by asynchronous sampling often affects the harmonic analysis accuracy. This paper examines a new approach for harmonic analysis based on deducing the modifier formulas of frequency, phase angle, and amplitude, utilizing the Nuttall-Kaiser window double spectrum line interpolation method, which overcomes the shortcomings in traditional FFT harmonic calculations. The proposed approach is verified numerically and experimentally to be accurate and reliable.K e y w o r d s: power system, harmonic analysis, barrier effect, window function, FFT

Enhanced Dual-Spectrum Line Interpolated FFT with Four-Term Minimal Sidelobe Cosine Window for Real-Time Harmonic Estimation in Synchrophasor Smart-Grid Technology

“…The signal frequencies are considered as 49.5 Hz and 50.5 Hz to justify the estimation accuracy under non-synchronous sampling frequency, the input signal is analyzed by using PLIS-based DSLIFFT with 4MSCW. The proposed PLIS-based DSLIFFT using 4MSCW results are compared with the conventional DSLIFFT algorithm reported in [11][12][13][14][15][16][17][18][19][20][21][22] using 4MSCW. The simulated benchmark signal waveform representation is depicted in Figure 3.…”

“…Here α takes integer values, and N is fixed to 2 k , where k is a natural number. Based upon the window function given in Equation (1) various advanced CWs are derived for harmonic estimation [7][8][9][10][11][12][13][14][15][16]18,19,[21][22][23]. Given the main lobe, sidelobe, and sidelobe roll of rate requirements a 4MSCW is adopted for harmonic and synchrophasor estimation, a PLIS-based DSLIFFT algorithm has been developed to improve its accuracy matching with the RT signal analysis.…”

“…This procedure effectively decreases the computation process. However, the peak search process in the conventional DSLIFFT algorithm reported in the literature [11][12][13][14][15][16][17][18][20][21][22][23] will check for the entire frequency bin peak locations, which in turn increases the computation burden.…”

“…After obtaining the locations of the spectral lines, an interpolation method is applied to estimate the amplitude, phase, and frequency of the harmonic signal. The conventional DSLIFFT algorithm presented in the literature [11][12][13][14][15][16][17][18][19][20][21][22] is improved by using the PLIS method. The spectral line location of the h th harmonic component can be obtained from the PLIS method.…”

Improved Parameter Identification Method for Envelope Current Signals Based on Windowed Interpolation FFT and DE Algorithm

“…Several approaches have been reported to analyze harmonics, including wavelet transform [6,7], neural network [8,9], multiple signal classification (MUSIC) algorithm [10,11], fast Fourier transform (FFT)-based method [12,13] and so on. So far, it has been a difficult and important research direction to find a suitable wavelet basis function for harmonic analysis [14,15].…”