Contribution of Coordinated Charging of Plug-in Electric Vehicles to Urban Medium Voltage Distribution Grid

To facilitate the integration of Plug-in Electric Vehicles (PEVs) into distribution networks, this paper proposes a coordinated charging approach. This approach consists of several stages. At first, a stochastic model of PEV charging demand is developed. Then, the constraints introduced into the power system are integrated into the mathematical model. Finally, optimal coordinated charging decisions are made through an improved optimization technique. The approach aims to minimize the total losses of the grid without violating system constraints and PEV owners' satisfaction. This strategy enables active and reactive power support to achieve peak load shaving and voltage regulation. The capability of the proposed coordinated charging approach of PEVs in mitigating the negative impacts of the recharging load is investigated on a typical power system by solving a mixed-integer linear programming problem. The study is carried out for different penetration levels of PEVs by modeling the stochastic temporal and spatial natures of the driving patterns. The proposed model considers charging at both residential and public charging stations. The findings of the study on a real distribution system using real local driving patterns and vehicle fleet data prove that not only the technical challenges of the high-penetrated PEVs to the grid is managed, but also the grid operation indices are improved significantly.