The Analysis Of Electric Vehicle Charging Mode And Its Load Characteristics

Recently, electric vehicle comes into people’s life gradually. After the utilization of electric vehicles on a large scale, the demand on their charging power will impact power grid to some extent. Model of centralized charging is briefly introduced and the relationship between initial investment and the later running cost is also analyzed. Based on those, this paper establishes a math model of centralized charging under the background of time-of-use price. According to the model,3electricity price projects are proposed in this paper. Simulation has been carried out on a practical case in2020which is predicted according to the typical daily load curve in2010. The simulation results show the third electricity price project with self-adaptive characteristic can not only shift the load obviously, but also minimize the total cost of the centralized charging station, thus achieving a win-win situation for both of the power system and the charging station. In addition to the centralized charging, concept of the dispersed charging is also introduced and the statistical model of electric vehicle’s power demand under this condition is built. This model considers3random variables consisting of Beginning Time of Charging, Driving Distance during One Day and Charging Power. The mathematical expectation of single electric vehicle’s power demand and its standard deviation are solved.After that a method to compute total power demand of many electric vehicles is given. Still taking the daily load curves in a certain day for example, the impacts of power demand of electric vehicles in different scales on original load curves are calculated. Calculation results show that under the condition in this paper the natural charging characteristic of electric vehicles makes maximum load of power grid increased to a certain extent. Discourse the application of electric vehicles on the basis of charge and discharge mode. Analysis the V2G functional of the two-way interaction between electric vehicles and the power grid, and then gives the implementation about the two-way interaction.