Integrated reactive power optimization for distribution systems considering electric vehicle dis-/charging support

Abstract

Electric vehicle (EV) charging, and discharging have an important reactive power support capability for the distribution network, for which a reactive power optimization method considering EV dis-/charging is proposed. Firstly, the principle of charger’s reactive power regulation is analysed,​ and a charger state constraint model is established to satisfy the constraints on the power factor angle by modifying the charger state for the battery capacity and the target power of the users. Secondly, a quantification method for user reactive power optimization subsidies is proposed to establish network-side and user-side demand indicators respectively, and to integrate reactive power optimization target function for the distribution system. Then, bi-directional charger’s PF is taken as the optimization variable, and the charger power factor angle optimization method is proposed based on the Particle Swarm Optimization (PSO) algorithm, so as to establish a reactive power optimization model considered the orderly dis-/charging, in order to realize the active/reactive power regulation between the distribution network and Owners of the EV. Finally, simulations are carried out using the IEEE-33 model as an example. Results proved that presented orderly dis-/charging method can increase voltage profile and decrease loss rate of the network to 40%, but also significantly decrease customer’s expenditure to 13%, while satisfying the temporary travel demand of customers.

Keywords

• Electric vehicles
• Bi-directional chargers
• Power factor angle
• Ordered dis-/charging
• Reactive power optimization