Study On The Influence Of Large-Scale Electric Vehicle On Power Grid

Electric vehicles due to its special energy drive that can improve energy efficiency and reduce pollution of the environment, is increasing concern.Countries also adopted a positive policy measures to encourage the development of electric vehicles.However, electric vehicles as a kind of special loads thier charging behavior is random and intermittent.If electric vehicles are charged without ordering on a large scale,it may lead to the “peak plus peak ”load problem, which will be a pressure on the structure and operation power grid, and affecting the safe and economic operation of power grid. As a result, mesures should be taken to control electric vehicles’ charging behavior Meanwhile, with the development of V2G(Vehicle-to-Grid) technology,electric vehicles can also be used as energy storage device instead of loads, supplying electric power to the grid at specific time. It will be great value in grid load shifting,eliminating new energy and so on. Therefore, the study of electric vehicles’ charging and discharging characteristics, adopting appropriate strategy to dispatch electric vehicles’ charging and discharging behavior orderly, taking full advantages of electric vehicles’ efforts on the grid load shifting, eliminating new energy and so on, is of great significance to improve the safe operation of power grid and energy efficiency.Based on the probability distribution of the travel distance and ending time for an owner in a day, this paper used the Monte-Carlo method to conduct random sampling,and establish the statistical model of random charging and discharging power after electric vehicles’ large-scale incorporation into the power grid. Taking the load level of some region as the reference, the influence on the local loads after different scale electric vehicles access to the grid was considered, as the basis for analyzing the impact of electric vehicles on the grid, which is of great significance for the planning and operation of the power system.A electric vehicles’ charging and discharging orderly dispatching strategy is proposed to reduce the negative impact of the charging and discharging on the grid and play its role in energy storage. By analyzing the needs of charging and discharging for users, a mathematical model was established, whose objective function is to smooth grid load fluctuations, reduce power loss and reduce the cost of charging for users.Considering the charging and discharging characteristic of battery, available capacity,grid voltage offset and other constraints, the genetic optimization algorithm is used to solve the stochastic optimization model.According to the consumption of wind power, solar photovoltaic power generation and other new energy problem, a electric vehicle collaborative charging and schedulingstrategy is designed. Based on the behavior of electric vehicle charging and the relevance and complementarity between renewable energy and grid load, the multi-objective optimization model for coordinated control of electric vehicles and distributed energy is established. The new model is aimed to suppress fluctuations in new energy output,reduce power loss and reduce the cost of charging for owners. It can also adjust the charging and discharging power of electric vehicles dynamically, match loads and power fluctuations of distributed generation in a good way, and reduce the impact of intermittent of distributed generation on the power grid.Finally, with the simulation of the example, the effectiveness and feasibility of proposed electric vehicles’ charging and discharging orderly dispatching strategy is verified. It’s of pratical effects on improving the characteristics of power grid and has certain reference value for the planning and operation of the power grid in the future.