Research On Optimization Strategy Of Orderly Charge And Discharge Of Electric Vehicle Considering Both Sides Of Supply And Demand

Electric vehicles(EVs)has attracted wide attention in recent years because of its advantages of environmental protection,energy saving and high efficiency.The entry of large-scale electric vehicles into the network is one of the typical signs of the smart grid in the future.The charge and discharge behavior of EVs is random and aggregated,and disorderly charge and discharge will bring risks to the safe operation of the power grid Therefore,it is necessary to guide EVs charge and discharge behavior in an orderly manner.With the continuous improvement of two-way charge and discharge technology(Vehicle to Grid,V2G),EVs can be equivalent to a mobile energy storage device,which can participate in power system peak regulation while taking into account the interests of both the grid side and the user side.The research content of this paper mainly includes the following aspects:First of all,the influence of disordered charge and discharge mode of EVs on the safe operation of power grid is studied.The influence factors of charge and discharge load are determined,the charge and discharge behavior is simplified according to the law of user behavior,and the probability density function of initial charge and discharge time and daily mileage is obtained by analyzing the load characteristics of EVs charge and discharge.The disordered charge and discharge load model of EVs is established.The variation of the daily load curve of the community in the disordered mode is obtained by Monte Carlo algorithm.The simulation results show that under the unguided measures,the difference between the peak and valley of the daily load increases,and the phenomenon of "adding peak on the peak" occurs,which affects the operation safety of the power gridSecondly,in order to alleviate the burden on the power grid caused by the disorderly entry of EVs,an orderly charge and discharge model considering user response is proposed by using the time-of-use electricity price of peak and valley.The guiding principle of time-sharing electricity price is explained,and the initial charge and discharge time of EVs in ordered mode is obtained.The concept of responsiveness is introduced,and the orderly charge and discharge load model of EVs under time-sharing electricity price is established.The relationship between responsiveness and charge and discharge load of EVs is obtained by Monte Carlo simulation.The simulation results show that "peak cutting and valley filling" can be effectively realized with the increase of user responsibility.A new load peak will be formed in the original valley period,which will also bring pressure to the operation of the power grid.Finally,in view of the shortcomings of the previous two charge-discharge modes,the original time-sharing electricity price is improved and an orderly charge-discharge optimization strategy is proposed.This paper studies the method of determining the upper and lower limits of EVs charge and discharge price,comprehensively considers the interests of power grid side and user side,takes the minimum peak-valley difference rate of daily load and the lowest user cost as the optimization objective,selects the peak-valley time-sharing interval as variables,establishes the optimal charge and discharge model of EVs,and uses NSGA-II and particle swarm optimization to solve the optimal charge and discharge time period respectively.The simulation results show that the two optimization algorithms have a certain effect on reducing the peak-valley difference rate and the user cost,and verify the correctness and effectiveness of the orderly charge and discharge optimization strategy.The comparative analysis shows that NSGA-? algorithm has more advantages in optimizing time period,which provides a basis for EVs in optimizing power load curves.