Multi-period Coordinated Dispatch For Electric Vehicles In Distribution Systems With Renewable Energies

With growing sustainable development of energy problems and environmental protection problems,electric vehicles,as clean vehicles,have aroused wide public concerns in recent years.Based on the predictive and actual information of power systems in different time periods,this paper models the charging demands of electric vehicles under various patterns,considers the electric vehicle users' satisfaction degree towards travel needs,and raises a multi-time scale dispatch scheme of electric vehicles.The dispatch scheme can not only enrich the methods of controlling power systems on the theoretical level,but also has great significance in the applying dispatch to the real power system.The main contents and achievements of this research are as follows:(1)Charging power models of electric vehicles are built,and the carrying capacity of distribution networks when there are large-scale electric vehicles accessing the network is analyzed.According to different charging patterns needed,the model creates a variety of charging power models for electric vehicles,which lays the foundation for electric vehicles' multi-time dispatch.From the security and economic point of view,in different control modes,the carrying capacity of electric vehicles under extreme or non-extreme condition is analyzed.(2)A dispatch strategy which takes users' satisfaction degree toward travel needs into consideration is proposed.From the predictive information recently,the model comes up with electric vehicle grouping criteria,and it greatly reduces the dimensions of electric vehicles' dispatch model.Meanwhile,the model refers to electric vehicle users' travel needs to improve their willingness to get involved in the power system dispatch.Interval optimization is employed to solve the model in order to ensure that the electric vehicles dispatch strategy obtained is a feasible solution.The present dispatch strategy can act as a basis for subsequent dispatch,and can also be used directly in real-time dispatch of electric vehicles with rolling updated information and real-time information is not available.(3)A rolling dispatch strategy based on two-stage optimization is presented.On the basis of the rolling update values of uncertainty in the power system,such as electric vehicles and renewable energy sources in this model,a multi-objective optimization dispatch that aims at stabilizing active power of the distribution network and reducing the power losses is set up.On the foundation of the former dispatch,this model revises the prediction error,and updates the dispatch continually.Two-stage optimization is adopted to reduce the difficulty of solving this model and enhance the computational efficiency of this model.(4)A real-time dispatch strategy for electric vehicles in reference to wind power's random fluctuations is put forward.Taking tracking wind power's random fluctuations and achieving the current day-ahead or rolling dispatch strategy as objective,wind power's random fluctuations in extreme short time is analyzed to implement the real-time dispatch according to current practical situation.And it also brings up the charging and discharging priority indicators of electric vehicles.On the premise of meeting electric vehicle users' demands and satisfying the requirements of real-time dispatch on response time,each individual electric vehicle in dispatched.