Abstract:The nonlinear loads and power electronic equipment have introduced a large number of harmonics and inter-harmonics into the power system, posing a threat to the safe and stable operation of the power system. The existing DFT technology has a low frequency resolution. When the frequency interval between the interharmonic and the fundamental or harmonic is small, the adjacent frequency components cannot be accurately distinguished. Algorithms with higher frequency resolution, such as Matrix Pencil Method, usually require a lot of calculations and can only perform offline analysis of harmonics and inter-harmonics. Combining ApFFT and Taylor Fourier multi-frequency model, this paper proposes a harmonic and interharmonic analysis model with high frequency resolution and small calculation amount, and its frequency resolution is much greater than that of traditional DFT technology, and its operation speed is about 39 times that of the Matrix Pencil Method. The noise robustness, frequency resolution, calculation speed of it have been simulated and verified by experiments in this paper. The simulation and experimental results show that the proposed model has good noise robustness and needs small amount of calculation, the frequency resolution can reach 12Hz. The frequency error and amplitude error during harmonic and inter-harmonic analysis is less than 0.01Hz and 5% respectively, and it can realize rapid detection of harmonics and inter-harmonics.
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