Distributed Charging and Discharging Strategy for Electric Vehicle Considering Three-Phase Load Balance for Incremental distribution network

Abstract

The unbalanced three-phase may occur in distributed network with large-scale uncontrolled charging loads of electric vehicles plugged in, at present, most of the researches on the coordinated electric vehicles charging and discharging strategies are based on the assumption of single-phase power networks, the load balancing constraints of three-phase are not considered. In this paper, a centralized charging and discharging optimization model for electric vehicles is established aiming to achieve a valley-filling concept, it can allocate electric vehicles demand during valley hours. Based on this, a distributed charging and discharging optimization method for electric vehicles considering three-phase load balancing constraints is proposed, and then the centralized optimization problem is decomposed into multiple sub-optimization problems, and a penalty term is added to the single electric vehicle charging and discharging optimization objective function. Solve the three-phase load imbalance problem in distribution network operation, and use CPLEX solver to solve the optimization model in MATLAB. Combining with information interaction mechanism, through the method of iteratively correcting the virtual electricity price, the orderly intelligent charging and discharging of electric vehicles can be realized. The IEEE 33-node distribution system is used for simulation analysis to verify the characteristics and effectiveness of the proposed method.