| At present,China is vigorously developing the electric vehicle industry,which is of great significance for environmental protection,energy conservation and emission reduction.However,as more and more electric vehicles are put into use,the impact and influence of its charging process on the power grid is becoming greater and greater,especially in the distribution network.As a kind of random mobile load,the large-scale integration of electric vehicles into the power grid may lead to some power quality problems,such as the overload of distribution network lines,the increase of line loss,the decrease of voltage and so on.It is of research significance and value to use the mobility and scheduling of charging load to correctly guide the orderly charging of electric vehicles,so as to reduce the adverse impact on the distribution network and even convert them into the favorable impact.In this paper,a quantitative analysis of the impact of unordered charging load on the distribution network and how to schedule vehicles for orderly charging were carried out.Firstly,the advantages,disadvantages and application fields of several common electric vehicles and power batteries are analyzed and summarized in details.By comparing,lithiumion batteries with small volume,long life and high specific energy are used as the research object in this paper.Then,the author analyzed the structure and charging and discharging principles of lithium-ion batteries in details.What's more,the structure and working principle of the charging pile are briefly described.Because a large number of harmonics will be generated in the working process of the charging pile,the charging process of the charging pile is modeled with the help of MATLAB software platform.The effectiveness and superiority of APF in harmonic control of charging pile are verified by simulation.Secondly,based on the full analysis of the factors affecting the charging load and distribution of electric vehicles,the charging load model of electric vehicles is established,which used the statistical data of the Department of Transportation of the United States in 2017 on the travel law of household cars in the United States.The unordered charging load of electric vehicle is calculated by MonteCarlo random simulation algorithm,and the influence of electric vehicle charging on the distribution network load curve under different permeability is analyzed.Then,the typical IEEE33 node distribution system is taken as the simulation object,and the node voltage offset rate and system network loss rate are taken as the index.The control variable method was adopted to comprehensively analyze the influence of large-scale electric vehicles on the operation stability and economy of the distribution network from different perspectives.Finally,an intelligent orderly charging strategy based on smart grid and internet technology is proposed in order to minimize the adverse impact of unordered charging of electric vehicles on the distribution network,and at the same time improve the utilization efficiency of the power supply units in the distribution system and the capacity of the original distribution network to electric vehicles.Intelligent charging scheme considers the owner's subjective selectivity.Taking the time-sharing and partition electricity prices as the guiding means,and aiming at the minimum daily load standard deviation and the minimum user charging cost of the distribution network.Therefore,the intelligent charging orderly dispatching model of electric vehicles is established and the MOPSO intelligent algorithm was used to solve the optimization model.The results show that the proposed scheme can achieve charge transfer of load in time and space,so as to ease the distribution network load fluctuation,enhance the utilization efficiency of generator sets,improve the operation quality of power grid operation,and reduce the cost of charging users.Therefore,it achieved the expected research objectives. |
PDF Full Text Request