Integration Of Plug-in Electric Vehicles In Power Systems:Intelligent Network Control, Unit Commitment And Economic Analysis

With the continuous development of renewable energy generation technologies and increasing pressure to combat the global effects of greenhouse warming, plug-in electric vehicles (PEVs) have received worldwide attentions. When a large number of PEVs are introduced into a power system, there may be extensive impacts on power system planning and operation, as well as on electricity market development. It is therefore necessary to properly control PEVs’charging and discharging behaviors. Meanwhile, the vehicle-to-grid (V2G) technology could serve as the energy storage to mitigate the intermittency and uncertainty of the renewable energy generation as well as effectively to provide regulation and spinning reserve ancillary services. Research work done in this thesis includes three parts:the design of an intelligent network application system for PEVs and its associate communication mechanism; unit commitment in power systems considering PEV and Plug-in Hybrid Electric Vehicle (PHEV) applications; and the economic evaluation on PEV participations in ancillary service markets. Detailed contents include the followings:1) A brief research survey is provided on how PEV applications would impact the power system when a high level of PEV penetration happens in the future, including: the impacts of the PEV application on transmission and distribution systems; PEV load characteristics; when acting as energy storage, how PEV could provide synergy with renewable energy generation integrating in a power system.2) An overview is made on the global PEV developing status, deployments of charging stations, and discussions on the eco-system of PEVs and the practices and challenges concerning the operation business model presented, with the emphasis on China PEV industry analysis, vehicle and battery manufacture and the government setting goals and sponsoring policies. An aggregator based architecture is briefed and represents an effective architecture to control groups of PEVs for providing ancillary services. The challenges and opportunities on the PEV industry in the near future are pointed out.3) An intelligent PEV network architecture is developed in this thesis including different layers as:the smart terminal device layer, charging and discharging access layer, application layer and backend operation and management layer. The detailed designs of the application layer, including the charging and discharging controlling system, as well as mobility and roaming management are provided. An effective associated communication mechanism is suggested with the following aspects:user authentication, roaming location updates, charging and discharging strategy decision-making and its commanding, and its related billing record generation. The presented architecture leverages the philosophy in mobile communication network buildup.4) A new unit commitment model and its solution method that takes into account the optimal PHEV charging and discharging controls is presented in this thesis. A10-unit and24-hour Unit Commitment (UC) problem is employed to demonstrate the feasibility and efficiency of the developed method, and the impacts of the wide applications of PHEVs on the operating costs and the emission of the power system are studied. Case studies are also carried out to investigate the impacts of different PHEV penetration levels and different PHEV charging modes on the results of the unit commitment problem. A100-unit system is employed for further analysis on the impacts of PHEVs on the unit commitment problem in a larger system application. Simulation results demonstrate that the employment of optimized PHEV charging and discharging modes is very helpful for smoothing the load curve profile and enhancing the ability of the power system to accommodate more PHEVs.5) How to make PEV provision profitable in the marketplace is an essential subject for the mass deployment and growth of the PEV industry. The PEVs with the V2G technology that can effectively be controlled by the aggregators on charging and discharging has the potential to supply ancillary services with rapid response and at low cost, especially with respect to regulation and spinning reserves. This thesis examines the economic feasibility of PEVs’ participation in ancillary service markets. In this thesis, an optimization model is developed to maximize aggregators" profits in the markets of regulation and spinning reserves through controlling the scheduling of the charging and discharging of PEVs. The objective function of the model takes into account of the ancillary service revenue, electricity energy discharge revenue and emission benefit gain deducted by costs of battery charging and battery depreciation. The developed model is simulated using driving pattern statistical data from the New Jersey region in USA, and electricity market price data from New York Independent System Operator (NYISO) are employed for the analysis. Simulation results indicate that aggregators can create profits by providing regulation and spinning reserve services in actual electricity market environment in most scenarios.