A Harmonic-to-Harmonic Detection Method Based on Nuttall Dual-window All-Phase FFT

Abstract

The invention relates to a harmonic and inter-harmonic detection method based on Nuttall dual-window all-phase FFT (Fast Flourier Transform). Existence of harmonics and inter-harmonics in a power grid brings great harm to a power system. The traditional FFT (Fast Flourier Transform) transformation algorithm has certain problem in aspects of spectrum leakage suppression and phase detection. In order to improve the measurement precision, all-phase FFT (apFFT)with phase invariant characteristics and a good spectrum leakage suppression function is introduced and is combined with a Nuttall window with good sidelobe characteristics, an FFT / apFFT phase difference correction method is then adopted to correct the detection amplitude and the detetcion frequency, and harmonic and inter-harmonic detection in the power system can be realized. The method has obvious advantages in aspects of spectrum leakage suppression and phase detection. Compared with the traditional method, the method of the invention has better precision. In the case of complicated power harmonic detection and especially in the case of inter-harmonic existence, the robustness and the reliability are good.

Description

technical field [0001] The invention relates to the technical field of power system power quality, in particular to a method for detecting harmonics and inter-harmonics based on Nuttall double-window all-phase FFT. Background technique [0002] With the development of smart grids, various new energy sources such as wind energy, solar energy, and bioenergy are connected, causing harmonics and interharmonics to become important factors affecting power quality and grid security. How to detect harmonics and interharmonics with high precision It has become one of the important research topics in the field of electric power to eliminate and suppress the wave. At present, the detection of harmonics and interharmonics is mainly done by Fast Fourier Transform (FFT), but in the case of asynchronous sampling, its detection accuracy will be seriously affected due to the fence effect and spectrum leakage. Therefore, it is very important to study and find new ways to carry out related me...

AI Technical Summary

Problems solved by technology

In the field of harmonic analysis, because the traditional windowed interpolation FFT algorithm still has problems such as complex correction and inaccurate phase measurement, some researches have also introduced all-phase analysis into harmonic analysis. The above provides a good idea, but there is still room for further improvement in terms of the completeness and accuracy of the algorithm

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