Research On Electric Vehicle And V2G Technology-Charge And Discharge Power Prediction And Participation In Power Grid Frequency Control Strategy

Under the pressure of energy shortage and environmental pollution,electric vehicles have become the main development direction of new energy vehicles.The continuous expansion of electric vehicles brings new challenges and opportunities to the safe and stable operation of power grid.When connected to the grid,electric vehicles can be used as controllable loads and distributed energy storage units.With reasonable control,electric vehicles can effectively assist the stable operation of the power grid.On the basis of fully considering the charging load characteristics of electric vehicles,it is of great theoretical significance and application value to discuss the related strategies of electric vehicles participating in grid auxiliary services,which can improve the stable operation level of the grid and the capacity to accept new energy.This dissertation first introduces the concept of V2G.According to the characteristics of electric vehicle with small available capacity and large dispersion,a hierarchical and partitioned control mode is proposed for scheduling control.A third part deals with the electric vehicle control center which is established between the power grid dispatch center and electric vehicle users to serve as the link of communication and coordination between them.In this dissertation,based on the statistics of vehicle travel,Monte Carlo random sampling simulation is used to predict the charging load power and discharge capacity of electric vehicles in each scenario set.It is assumed that the charging and discharging time of electric vehicles follows a uniform distribution and the average daily driving distance follows a logarithmic normal distribution,to predict the random load of electric vehicles.This has a strong reference value for the grid dispatching center when making the dispatching plan,and also provides reliable data basis for the system to take security maintenance measuresSecondly,the energy supply mode and access mode of electric vehicles are introduced.The feasibility of frequency regulation of electric vehicles is analyzed from the aspects of regulation characteristics,response mode,available time and capacity.Based on the economic analysis of electric vehicle regulation,the calculation method of frequency modulation price and frequency modulation income method of electric vehicle participating in power grid frequency regulation are put forward.Finally,based on the decentralized V2G mode,the coordinated control strategy of electric vehicle charging load participating in grid intelligent frequency response is proposed.According to the frequency deviation degree of the power grid,the grid frequency is responded to step by step,and the charging/discharging power of electric vehicles is adjusted and controlled reasonably,so as to realize the friendly interaction between electric vehicles and the power grid.The coordinated control strategy adopts asynchronous and active response,and different electric vehicle charging loads respond at different time nodes.Power System Analysis tools(PSAT)are used to analyze the frequency variations of Power systems under different disturbances,and the results demonstrate the effectiveness of the proposed methodThe work done in this dissertation can provide reference for the large-scale grid access of electric vehicles in the future and the effective assistance to the safe and stable operation of the power grid.