Hierarchical And Partitional Real-time Dispatching Strategy For Charging And Discharging Of Electric Vehicles Considering The Transferable Margin Of Charging/discharging Energy

In recent years,the development of electric vehicles(EVs)has been strongly supported by the government and has raised wide concerns.With the ever-increasing penetration of EVs,the uncoordinated charging and discharging of numerous EVs may result in significant negative impacts on the secure and economic operation of the power system concerned.In addition,with the rapid development of V2G technologies,more and more scholars have studied the provision of auxiliary services such as peak shaving,frequency regulation and spinning reserve to power systems through EV participating in V2G.It is of practical significance to study coordinated charging/discharging strategies of EVs.Given this background,some relevant topics have been studied and the main contributions of this thesis can be summarized as follows:(1)A real-time dispatching strategy for charging and discharging of EVs is proposed,considering the transferable margin of charging/discharging energy.First,the transferable margin of charging/discharging energy is defined to quantify the flexibility of charging/discharging dispatching strategy,with the dispatched time,transferable load of EVs and willingness-to-participation of EV owners taken into account.Then,a real-time dispatching model for coordinated charging/discharging of EVs is presented with the transferable margin of charging/discharging energy considered.A two-step strategy is adopted to attain the charging/discharging dispatching strategy for each dispatching period.In the first step,a quadratic programming model is formulated to determine the total power of EVs with an objective of minimizing the variance of the total system load over a specified dispatching period.In the second step,the target is to obtain the charging/discharging dispatching scheme that meets the requirement of the total power of EVs through maximizing the total transferable margin of charging/discharging energy of EVs that are not charging/discharging in the current period,and an integer programming model is attained.Then,the highly efficient commercial solver,YALMIP/CPLEX,is employed to solve the developed optimization models.Finally,the effectiveness of the proposed strategy is demonstrated by a sample example,and simulation results show that the proposed strategy can effectively improve the system load profile.(2)A hierarchical and partitional real-time dispatching strategy for charging and discharging of numerous EVs is proposed,considering the integration of renewable energy sources.First,the hierarchical and partitional dispatching architecture for large-scale EVs dispatching is proposed.Then,the uncertainty of the renewable energy output is modeled by scenario analyses.Next,a hierarchical and partitional real-time dispatching model for coordinated charging/discharging of EVs is presented with power network constraints considered.A two-step strategy is adopted to attain the charging/discharging dispatching strategy for each dispatching period.In the first step,a quadratic programming model is formulated to determine the total power of EVs in each regional control center with an objective of minimizing the variance of the total system load over a specified dispatching period.In the second step,the target is to obtain the charging/discharging dispatching scheme of each regional control center through maximizing the total transferable margin of charging/discharging energy of EVs that are not charging/discharging in the current period,and an integer programming model is attained.Then,the highly efficient commercial solver,YALMIP/CPLEX,is employed to solve the developed optimization models.Finally,the IEEE 3 3-bus system with four EV regional control centers is employed to demonstrate the effectiveness of the proposed strategy.