Impacts Of Electric Vehicles Charging On The Load Of Power System

Electric vehicles, as a new means of transport, have the incomparable advantage in alleviating the energy crisis and reducing environmental pollution over conventional cars. Because of uncertainty of EVs'activities in time and space, free charging may lead to power consumption increase during the peak load of the power grid, the burden aggravation of power grid, and system efficiency reduction. It is significant in improving the reliability and energy efficiency of power system, to build the model of charging power consumption of electric vehicles and to conduct the user with appropriate tariff strategies or controlled charging strategies.This thesis builds the model of power consumption of EVs based on the factors of charging, analyzes the impacts of tariff policy on EV power consumption, proposes a controlled charging strategy to smooth load profile of power grid, and finally builds a coordinated charging model with the integration of distributed resources:A model of calculating EV power consumption without any tariff policy or controlling strategy is built based on the analysis in the factors of EV power consumption and the study in the charging load model of a single electric vehicle. According to the calculation of the EV power consumption in Shanghai, charging would increase the peak-valley difference of load profile. As the foundation of analyzing the impact of charging on power grid, it is very important to calculate EV power consumption for power system planning and operation.Based on the analysis of electricity demand response and demand elasticity of EV users, the demand response model of EV users for dual tariff policy is proposed. And further the model of charging strategy under the dual tariff policy is built, to prove the validity in guiding users to charge EVs in off-peak periods. It provides a reference for the management and policy of EVs charging.The controlled charging strategy is proposed to reduce the negative influence of charging, and make use of EVs' energy storage capacity. By analyzing users'charging requirements, the optimal EV controlled charging model is established, considering the uncertainty of charging. It is based on the expectation model of stochastic planning, and aims to decrease the fluctuation of load of power grid. The charging dispatch scheme shows that controlled charging has a substantial potential on load shifting.For increasing the capability of accommodating wind power and solar power, the coordinated charging strategy is designed. Based on the correlation and complementarity between EV charging, renewable energy and load, the chance-constrained programming coordinated charging strategy is built. Simulations show the feasibility of dispatch charging of EVs to enhance the capacity of accommodating intermittent power. And the thesis provides a valuable exploration.