Smart Charging/Dischariging Control Of Electric Vehicles And Its Effecis On Power System Reliarbility

In order to reduce the external dependence of fossil fuels,alleviate the environmental problems such as smog caused by exhaust emissions from gasoline car,and achieve break-through in the automotive industry,China has included electric vehicles into the strategic emerging industries and introduced subsidies for purchases.This article mainly analyzes the large-scale integration problem of electric vehicles from two perspectives.The first is the use of smart charging and discharging control algorithm to guide the behaviors of electric vehicles.The second is to analyze the impact of large-scale integration of electric vehicles on power systm from the perspective of reliability,and explore how to use electric vehicles' characteristics of flexible and controllable to provide ancillary services for the power system.Based on the survey data and statistical results,this paper first carries out an accurate simulation of the charging load of electric vehicles.Then,a distributed smart charging control algorithm based on price guidance mechanism in a market environment was proposed.Each electric vehicle has enough intelligence and communication capabilities to determine its own charging strategy based on the charging price signal to achieve its own maximize revenue.The electric vehicle aggregator use the smart pricing mechanism and the sequential price update mechanism proposed in this paper to guide the charging behavior of the electric vehicle and achieve the control goal of peak load reduction and valley filling.In this paper,a discrete hybrid GSA-PSO optimization algorithm is proposed to solve the charging planning problem of each vehicle.This algorithm combines the social thinking of the PSO and the exploration capabilities of the GSA,it can avoid the situation that local optimum is trapped in the search process,and accelerates the convergence speed to the global optimal solution,which is very suitable for the scenario that electric vehicles have limited computing power.Aiming at the problem that electric vehicles discharging to the grid through V2G technology,this paper proposes a centralized smart charging/discharging control algorithm for electric vehicles.The algorithm changes the traditional role of electric vehicle as passive load in the distribution network,and then uses its flexibility and controllability to achieve the goal of reducing the peak load of the grid.EV aggregators monitor the status and behavior of all connected EVs in real time,and achieve the cost minimum goal by providing real-time control signals for each controlled EV.In order to solve the problem of dimension disaster caused by the centralized optimization probelm,this paper proposes a dominant matrix method to reduce the search space reasonably,and uses a modified particle swarm optimization algorithm to solve the problem.Based on the sequential Monte Carlo simulation method,the reliability of the gener-ation system is analyzed and evaluated.Specifically,the impact of uncontroled charging load of electric vehicles on reliability and the effect of smart charging control algorithm to improve reliability are analyzed,which providea a new perspective for the evaluation and analysis of smart charging algorithms.Based on the operating characteristics of the power system and the controllable characteristics of electric vehicle,the feasibility and implementation mechanism of the coordinated electric vehicle to provide operating reserve to the power grid are discussed,and proposed an efficient method for estimating available capacity of aggregated electric vehicles.In this method,the available capacity of electric vehicle is divided into interruptible capacity and V2G capacity based on its status.Afterwards,this paper introduces the basic concept and analysis procedures of operation reliability,and an operational reliability analysis method based on modified PJM method is proposed.The simulation finds that unit commitment risk of the system has obvious discrete characteristics,the available operating reserve capacity provided by aggregated electric vehicles can significantly reduce the operation risk level of the system.