Analysis On Electric Vehicle Integration Technology And Social Comprehensive Benefits

Along with the fiercer and fiercer contradiction between economy development and energy supply&environment pollution, energy saving and reduction of the dependence on fossil fuel have become an urgent issue on domestic economy sustainable development. The electric vehicle (EV) is a kind of vehicle forced entirely or partly by electricity, by saving energy and reducing carbon emission through replacing petrol with electricity, EV becomes an important method to solve problems in transportation, energy and environment. Since the Eighth Five-year Plan, China has invested a large number of human resource and finance supply in EV research and development and a series of achievements have been obtained. Currently the small-scale demonstration operation of EV is going on in cities such as Beijing, Tianjin, Hangzhou and so on.The EV is a new kind of load for power system, charging from power grid randomly in aspects of both time and space. With the swift increase in the load curve caused by large scale EV charging intensively, security and stability of power system can be seriously affected. Being not only an electricity consumer but also the energy storage device, the EV can help solve problems such as load shifting and renewable energy intermittent through Vehicle to Grid (V2G) concept.Given this background, the impact of EV integration into power system, especially the distribution system, EV’s ordered charging schedule, battery switch station operation mode under microgrid environment and EV’s social comprehensive economy are investigated respectively. The research results are obtained as follows:1) As a stochastic load both in time and space, EV charging from power system will influence unit commitment in the generation side, decrease transmission capacity adequacy and affect electricity quality and supply-demand balance of distribution system. Especially for the distribution system, the overload, over-limit voltage, increased transformer failure and aging, distortion of voltage and current wave induced by EVs random charging can seriously threat power system security and stability operation. Thus the investigation in EV ordered charging/discharging schedule is necessary.2) The development of smart grid technology, especially EV charging/discharging technology makes it possible to dispatch EV and wind power jointly. EVs with V2G function can provide frequency regulation or spinning reserves to wind power when it is necessary to reduce negative influence of wind power forecasting error. Based on which, an EV ordered charging/discharging model with the aim of maximizing EV agent’s benefits is developed and particle swarm optimization (PSO) is utilized in solving the problem. The results of the test example show that with this ordered dispatching model, EV agent can obtain benefits through providing spinning reserves to wind power and the negative effect of wind power forecasting error can be reduced.3) Battery switch station can be regarded as the storage system when taking part into microgrid operation for the purpose of adopting renewable energy as much as possible. The battery switch station operation mode is proposed with the goal of minimizing the switching power between microgrid and main grid, satisfying EV owners’battery switching demand. The simulation result shows that the proposed operation mode can help battery switch station improve microgrid operation performance such as absorbing extra renewable power or providing inadequate microgrid power generation, and the more batteries the station possesses, the better the station performs.4) Compared with traditional vehicle, EV’s large scale application can realize more social benefits, including energy saving, carbon emission reduction and power system operation cost decrease. Through developing the evaluation model of EV social comprehensive benefits and calculating2020EV social benefits based on the developed model, the conclusions can be made: the economy of EV in aspects of energy saving, carbon emission reduction and power system fluctuation decrease is obvious compared with traditional vehicles; the smaller the occupation of thermal power generation among total power generation, the larger the EV social comprehensive benefits; the higher the EV penetration, the better the EV’s ancillary service ability, thus the larger the benefits of it.Finally, several conclusions are obtained based on the research outcomes, and directions for future research indicated.