Coordination Strategies for Electric Vehicle Chargers Integration in Electrical Grids

Currently, smart grids are integrating electric vehicles into the power grids. However, the uncoordinated electric vehicle charge can lead to overloads in the transformers due to power increases during peak hours. Therefore, this paper presents different coordination strategies for charging electric vehicles, by constraining the power delivered by the grid with the transformer limits. In particular, two optimal strategies are assessed and compared with a standard approach, that has an uncoordinated electric vehicle charge operation. The first optimal strategy looks for charging the electric vehicles when the electrical energy price is lower. The second strategy aims to provide flexible capacity to the electrical grid leading to a smooth behaviour in the power demanded by the station. These optimal strategies are proposed to integrate the electric vehicles into the electrical grids and avoid overloads in the transformers. The strategies are validated in the case study which presents the worst-case scenario in terms of the week with more charging events per charger.