Research On The Influence Of Large-scale Solar Cell Module Surface Shading On Power Quality Of Distribution Network

Solar energy is currently one of the cleanest renewable energy sources in the world with the cleanest power generation process,the easiest and most realistic production process,and the most promising.With the large number of grid-connected photovoltaic power generation systems of thousands of watts and hundreds of megawatts,solar power systems have The safe and stable operation of the power system and power quality have had a serious impact.A series of technical problems such as low power quality and over-limit voltage fluctuations in the distribution network need to be resolved urgently.When the large-scale component surface is shielded,the power fluctuation caused by the power distribution network system generates resonance and harmonics,which limits the large-scale application of solar power generation systems.In order to analyze the impact of large-scale solar module surface shading on the power quality of the distribution network,based on the actual operation of a photovoltaic power station in Jiuquan area,a large-scale photovoltaic power station model that can simulate various power quality prob lems analysis is established,so as to combine theory with reality,Verify and solve the problem.In this thesis,through theoretical simulation,the problem of harmonic interaction and harmonic suppression strategy generated after the surface of large-scale solar power system components is shaded is studied.Firstly,the basic characteristics of solar cell modules,the output characteristics of different shades of modules,the influence of surface ash on the performance of modules,and the influence of partial shades of any proportion of modules on the inverter were studied and verified.Photovoltaic module characte ristic test under shading,under a specific ratio of shading,surface shading and dust accumulation on light transmittance test,and shading on photovoltaic module characteristics.Secondly,it studies the influence of solar cell module surface shading on the output characteristics of the module,the output characteristic of the module is affected by the shading effect on the voltage/current of the inverter,and the large-scale solar power system composed of a large number of inverters.The impact of grid p ower quality.It reveals the particularity of the harmonic output after the large-area module surface is shielded.Experiments on the waveform load of the inverter with different loads(meaning different degrees of module surface shading)have been establi shed to establish a grid-connected photovoltaic power generation system module surface shading model,including photovoltaics Modules,photovoltaic arrays,inverter modules,etc.,and verify the theoretical results through the established simulation model.Through the research and simulation analysis of the simulation model of the solar power generation system,the main factors affecting the power quality of the distribution network are determined,as well as the specific impact on the power quality of the distribution network when the large-area component surface shade ratio is different and changes at any time.Finally,study the impact of large-scale grid-connected solar cell module surface shading on the power quality,voltage,current,and islanding effect of the distribution network and formulate corresponding preventive measures.Research the harmonic characteristics of grid-connected photovoltaic inverters that affect the power quality of the distribution network,analyze the harmonic characteristics of grid-connected inverters in the system,and analyze the impact of large-scale grid-connected photovoltaic modules on the distribution network Carry out analysis,optimize the inverter control strategy under the shielding situation,analyze the reasons for the harmonics generated when the inverter power fluctuates on a large scale(that is,when the large-scale component surface is shielded),and formulate measures to eliminate harmonics.The improved filtering effect of the inverter and the effect on the power quality of the distribution network were verified under working conditions,and good results were achieved.A technical transformation was successfully completed,and theory was integrated with practice to solve practical problems.This thesis analyzes the power quality impact of photovoltaic power stations integrated into the distribution network from the production side.Its modeling methods,research ideas and control strategy optimization can be used for large-scale new energy grid-connected characteristics research,engineering design ideas,and control strategy improvements.And improving the ability of the distribution network to accept new energy provides a certain theoretical reference.