The Influence Of Photovoltaic Power Station In Shenyang On Power Quality Of Distribution Grid

During the "13th Five-Year Plan" period,with the depletion of traditional energy sources and the worsening environmental pollution in China,the construction of large-scale clean energy bases and UHV AC and DC transmission projects will lay a solid foundation for the prevention and control of air pollution projects.As a major form of new energy,solar energy is developing in the direction of large-scale and base-based operations around the world.Several megawatt grid-connected photovoltaic power stations in China have started operation in Xinjiang,Sichuan,Inner Mongolia and Qinghai.However,PV power plants have problems such as low power quality and limited grid voltage fluctuation.When the system impedance such as transformers and transmission lines are large or the installed capacity is increased,resonance of the photovoltaic power generation system is induced,which limits the photovoltaic Large-scale application of power plants.In order to analyze the impact of PV power station on the power quality after the access to the regional power grid,this paper focuses on the current situation of the impact of PV power station integration on power quality in Shenyang region.Based on the actual operation data of Shenyang PV power station,Quality problems of a large-scale photovoltaic power plant grid-connected power quality simulation model.Secondly,this paper mainly studies the power quality characteristics under three conditions: 1)constant power;2)power fluctuation;3)power mutation;4)load changes and system failure.Through the simulation analysis,it is found that the main factors that affect the power quality of the PV power station and the power quality problems most likely to occur in the PV power station when the external conditions of the power system change.In this paper,theoretical simulations are conducted to investigate the harmonic interaction effects and harmonic suppression strategies that occur when PV power plants are connected to the grid.Firstly,a dynamic mathematical model method for large-scale photovoltaic power plants was proposed,which revealed the particularity of the output harmonics of large-scale photovoltaic power plants,and analyzed the relationship between the harmonic power output of the photovoltaic power plant and the light intensity and the surface temperature of the battery.Secondly,the photovoltaic power station transmission in Shenyang was established.The mathematical model of the distribution system reveals the mechanism of the harmonic interaction between the PV power plant and the power grid,especially considering the distributed capacitance of the high-voltage transmission line system,the load on the line and reactive power compensation devices,etc.;The access capacity of the power station and the planning of the power grid structure are analyzed.The control plan for the system voltage support problem is analyzed.A cascaded SVG simulation model for the reactive power compensation device of the photovoltaic power station is established.The above-mentioned control plan for the photovoltaic power station is analyzed in detail under different operating conditions.The governance effects of PV power plants have led to the solution of power quality problems applicable to PV power plants under different conditions.This theory analyzes the impact of photovoltaic power plant grid-connected power quality from the perspective of practical engineering.Its modeling methods,design ideas,and control strategies can be used to study the characteristics of large-scale new energy grid integration,engineering design ideas,control strategies,and evaluation grids.The ability to accept new energy provides a certain theoretical reference.