Analysis And Application Of Harmonic In Photovoltaic Power System

Along with the great development of exploitation and utilization of newenergy and PV industry of the country, photovoltaic power generation will bemore and more proportion in the whole power grid is high, due to powergeneration technology compared with traditional photovoltaic technology, it isinfluenced by light intensity, temperature and a series of unpredictable factorslarger, harmonic of the output will bring great damage to the whole power systemand customers. Harmonic state of the PV system does not require accuratestandards, just use the conventional power grid harmonic standards, research onphotovoltaic harmonic is great significance.In this paper, the power characteristics of PV systems research, especiallythe special nature of the PV harmonic analysis. Through the analog filter method;instantaneous reactive power theory method; wavelet transform; Neural Network;compare Fourier transform method, the paper selects the most widely usedFourier analysis, Fourier analysis of the first transform algorithm theory andapplied to signal analysis, spectral leakage when Fourier analysis method isapplied to harmonic analysis of photovoltaic and fence effect arising problemsare introduced. To solve these problems, study the common characteristics of thewindow function in the frequency domain and windowed interpolation algorithmfor spectrum leakage and fence effect of improved results, on the basis ofproposed improvements based on convolution Hanning window convolutionalgorithms, and gives step algorithm. By MATLAB simulation, the advantages ofthe improved algorithm to detect the weak harmonic amplitude and simplifiedcalculation to verify the amount, but for the existence of inter-harmonicgeneration systems were often used comparison window function simulation.For synchronous sampling PV elusive harmonic analysis, quasi-synchronoussampling method proposed software-based quasi-synchronous sampling canreduce spectral leakage and picket fence effect of generation, combined with improved Hanning window convolution algorithm can greatly improve theharmonic parameters analysis accuracy. While the quasi-synchronous samplingmethod and Hanning window convolution algorithm is applied to improve thephotovoltaic harmonic detection system, and with an accurate harmonic signalanalysis to verify the accuracy of the system harmonics. This provides a practicalreference value for the photovoltaic system harmonic control. Also provide thefundamental basis for the design of harmonic compensation device.