Influence And Strategy Of Distributed Photovoltaic Grid Connection On Distribution Network Voltage

In order to cope with the problems of environmental pollution and the shortage of fossil energy,the state has continuously increased its investment in new sources such as photovoltaics and wind energy,and vigorously developed renewable energy power generation technologies represented by distributed photovoltaics.Then,as the penetration rate of photovoltaic power sources in the distribution network gradually increases,due to the intermittent,random and volatile characteristics of its output,a large number of photovoltaic power sources will have an impact on the voltage of each node after being connected to the distribution network.,Causing voltage flicker and fluctuations.The use of complementary reactive power and voltage control strategies for photovoltaics is one of the effective strategies to reduce the impact of distributed photovoltaic grid connection on the distribution network.Therefore,the research on the optimization of distributed photovoltaic grid-connected operation has theoretical value and practical significance.First of all,this article provides a classification overview of photovoltaic power supply,maximum power tracking,and energy storage device models,and establishes a photovoltaic grid-connected model to lay a foundation for subsequent research.Furthermore,from the perspective of the mechanism of voltage fluctuation after photovoltaic power supply is connected,the change law of the voltage at each node of the distribution network without photovoltaic power supply and after photovoltaic power supply is connected is studied.Then,a calculation example is used to further verify the accuracy of the above analysis and research,and to prepare the theoretical foundation and basic research for the proposed optimization control strategy after the distributed photovoltaic grid is connected.Secondly,this paper proposes an in-situ control strategy for the node voltage of the distributed power distribution network to solve the problem of voltage limit caused by grid connection.Among them,in the case of not reducing the active power to the greatest extent,the local control combines the energy storage and the inverter capacity characteristics,and adjusts the voltage by adjusting the active/reactive power to the greatest extent using the inverter capacity.On the basis of the above-mentioned research results,the thesis considers the advantages and disadvantages of traditional control strategies,combines local control with centralized control,and proposes an optical storage in-situ-centralized voltage control strategy.First,the traditional droop control model is improved,and the boundary parameters of the control curve are adjusted.Second,the centralized control is calculated with the minimum network loss as the objective function.Finally,the obtained result is used as the adjustment basis for the local control,and verified by specific calculation examples.The effectiveness and rationality of the control strategy are improved.