An Interpolation Signal Reconstruction-based Harmonic And Inter-harmonic Analysis Algorithm For Grid

Harmonics and inter-harmonics are becoming increasingly serious pro blem with the widespread use of the influx of non-linear loads in power systems and new energy. At the same time, the demanding on power quality of the modern industry is increasingly. The prerequisite of power quality improvement and harmonic pollution control, which is the accurate extraction of p ower signal harmonics and inter-harmonics.The fundamental frequency of power system in the presence of irregular wave, which is difficult to realize synchronous sampling. Non-synchronous sampling and non-sampling the whole cycle will cause severe spectral leakage. Therefore, this thesis presents a interpolation signal reconstruction-based harmonic analysis algorithm, by the quasi-synchronization of non-synchronous sampling signal to achieving the purpose of suppression of spectral leakage and picket fence effect. In addition, according to the characteristics of interharmonic which are small amplitude and frequency uncertainty, this thesis presents a interpolation signal reconstruction-based interharmonic analysis algorithm based on the analysis of interference spectrum between harmonic and interharmonic. It is used for separating the harmonic and inter-harmonics, in order to reduce the mutual interference. To verify the veracity of the inter-harmonic detection algorithm based on reconstruction by interpolation, the thesis has seted up the hardware platform based on ADC+DSP framework, and on which verify effectiveness of the algorithm by means of measuring the harmonic signal generating by the standard source and inter-harmonic signal generating by the signal generator.This thesis consists of five parts. The first chapter is the introduction, briefly introduced the project background and significance of the research, the generation and harm of harmonic and inter-harmonic, harmonic and inter-harmonic detection technology research status and development trend and the project sources. The second chapter mainly introduces a interpolation signal reconstruction-based harmonic analysis algorithm by using interpolation method of reconstruction quasi-synchronous sampling sequence to reduce the FFT spectral leakage in a non-synchronous sampling condition.The third chapter analyzes the spectrum interferences between harmonic and interharmonic and details a interpolation signal reconstruction-based inter-harmonic analysis algorithm which improve the accuracy of the fundamental frequency estimation by improving the DFT algorithm, reducing interference spectrum to the fundamental frequency spectrum brought by the inter-harmonics.The main contents of the fourth chapter is through the MATLAB simulation to verify the effectiveness of the harmonic detection algorithm and the inter-harmonic detection algorithm, the analysis of the measurement accuracy, computational efficiency and anti-noise characteristics of the interpolation signal reconstruction-based harmonic and inter-harmonics analysis algorithm by setting comparative experiments of other measuring methods of harmonic and inter-harmonic The fifth chapter focuses on the hardware and software design of harmonic integrated detection system based on DSP, which including the signal conditioning module and data acquisition module, communication interface module, DSP minimum system module, power supply module. Finally test the interpolation signal reconstruction-based harmonic and inter-harmonic analysis algorithm on the hardware platform.The test results show that measurement error of harmonic and inter harmonic parameters which obtained by the harmonic integrated detection system can meet the GB/T 14549-1993 “Quality of electric energy supply- Harmonics in public supply network” and the GB/T 24337-2009 “Power quality-Interharmonics in public supply network”. The harmonic integrated detection system can achieve the A standard of harmonic and inter harmonic measurement instrument. Finally, summarizes the innovation and weakness of this thesis, points out the research work and prospect of the next stage.