The Effect And Control Measures Of Distributed Photovoltaic Grid-connected On Power Quality In Distribution Network

In recent years,the energy crisis and the environmental pollution problems have become increasingly serious.The documentary shooted by Jing chai fully reflects the serious of the problem of haze caused by burning of fossil fuels.As a new renewable,pollution-free energy,solar energy has been payed more and more attention and widely used to salve these problems above,but it also brings many new technical problems.Through the research of grid connection techniques of distributed photovoltaic power generation system and the current situation at home and abroad of its influence on the power quality of distribution network,this paper mainly studies the structure and principles of distributed photovoltaic power generation system.After building a simulation model of distributed photovoltaic power distribution network in Matlab,then the paper analyses the impact mechanism of distributed photovoltaic grid to the voltage of distribution network.It focuses on the solutions of adverse effects,and puts forward reasonable measures to pressure regulating.Firstly,the paper introduces the distributed photovoltaic power generation system.On the basis of understanding the primary principles of photovoltaic cells,the simulation system has been built.The paper introduces the characteristics of photovoltaic cells in detail.Then the maximum power point of the photovoltaic array tracking technology is also introduced,and the incremental conductance method is introduced in detail.Based on the above introductions,an improved incremental conductance method for maximum power point tracking problem is proposed,thereby inhibiting oscillation and misjudgment.This paper uses a single-stage grid connected mode to introduce the inverter simulation model and controlling strategy,and uses a PR and MTTP integrated controlling strategy to control the inverter.Then,it analyses the impact of distributed photovoltaic grid connected to the power quality of distribution network,and focuses on the analysis of voltage influence mechanism on single and multiple photovoltaic researches.Simulation can do help to the analysis of the influence caused by different grid position and different capacity of distributed photovoltaic.What's more,the research on optimal allocation is delivered to the grid position and the capacity of distributed photovoltaic power distribution network.By calculating the feasible assessing location of photovoltaic and proposing optimization method,the photovoltaic capacity is optimized on configuration and the problem is solved.Finally,improvement measures to the influence of distributed photovoltaic grid on the voltage of distribution network are put forward.When the traditional regulating transformer's transformation rate and the methods of distributed photovoltaic power's accessing position can not meet the pressure regulating requirements,VQC control which is based on fuzzy logic and SVC joint pressure regulating strategy are put forward.Simulation analysis can illustrate the feasibility of this method.