Research on Scheme for Ordered Charging of Electric Vehicles

Large-scale charging of electric vehicles(EV) in the future will affect power grid operation and unordered charging of EV will bring about negative impacts to power grid.Chargin load possesses adjustability in time-scale and space-scale,so it is possible to perform dual-scale load scheduling in time and space to make charging load of EV playing a positive role in power grid operation.Based on the feature of charging load and measured charging load data,a load forecasting-based ordered charging scheme is proposed and an optimization equation is established to obtain the optimal charging starting time for each charging load,and the total laod curve can be adjusted by changing charging starting times.On the basis of satisfying user demand,the proposed scheme can change EV in the valley period as far as possible to stablize the fluctuation of load and reduce load difference between peak and valley period,and the new peak load due to charging EV can be avoided.Simulation results shows that the proposed scheme is effective.It also can be seen from simulation results that due to the restriction of power characteristic of charging process and the influence of human behavior,it is unable to achieve ideal effect of load adjustment by means of charging EV only.