Research On Interharmonic Detection Algorithms For Wind-solar Complementary Generation System

With the increasing destruction of the environment and the large-scale development and utilization of traditional energy,renewable and green energy,such as wind energy,solar energy,tidal energy,etc.,have attracted people's attention.People have made great progress in the development and utilization of new energy,especially wind and solar power.Wind/PV Hybrid Generation System(WPHGS)is a new energy generation system which integrates the advantages and complementarities of solar energy and wind energy.It has high efficiency and high utilization.It has a good performance in alleviating energy crisis and solving environmental problems.Wind-solar complementary system not only produces a series of harmonics and interharmonics in the power grid,but also distorts the grid voltage,reduces the utilization of wind energy and solar energy,and reduces the power quality.It also interferes with relay protection devices,measuring instruments,precision instruments and communication signals.Many experts and scholars at home and abroad attach importance to the detection of Interharmonics in grid-connected WPHGS.The interharmonics of wind-solar hybrid power generation systems are characterized by small amplitude and variety,and rapid changes in real-time.This paper is used to detect common interharmonics(ie,fast Fourier method,wavelet algorithm,empirical mode decomposition(EMD),Modern spectral estimates(prony),Hilbert Yellow(HHT),etc.were compared.Due to the traditional method of detecting interharmonics,the mutual interference of harmonics and interharmonics,as well as some real-time problems,make it impossible to detect interharmonics well.In this paper,the improved windowed interpolation FFT algorithm and wavelet packet algorithm are used to detect the interharmonics.By comparing several common window functions and interpolation correction formulas,and comparing and detecting the data by simulation,four four-order Nuttall windows with high precision and small calculation amount are selected as the optimal interharmonic detection algorithm,and the wavelet packet can be utilized at the same time.The algorithm performs accurate and fast detection of interharmonic components.The improved DFT method and wavelet packet algorithm proposed in this paper are compared and verified.The proposed method can detect the interharmonics of WPHGS and improve the accuracy of traditional detection algorithms.The AD sampling module is built and the grid-connected signals of the existing wind-solar hybrid power generation system are collected.The algorithm is used to analyze and realize the detection and calculation of the interharmonic content,which makes it an effective solution to the intermediate harmonic problem of the WPHGS.