Review of electric vehicles integration impacts in distribution networks: Placement, charging/discharging strategies, objectives and optimisation models

Abstract

Vehicles around the world are being converted to electric power in order to combat climate change and lower pollution levels. Sustaining this process calls for more electric vehicle charging stations (EVCS) to be made available to the general population. The uncoordinated surge of electric vehicles (EV) and the EVCS will have repercussions on the distribution network, environment, EV users, and charging stations, posing significant technical, economic, and environmental issues. Coordinating and scheduling the charging/discharging of EVs at EVCSs is essential for preventing the issues. EVs may be employed as sources of distributed energy storage and leveraged to improve network performance and efficiency with suitable charge/discharge control management. This paper examines various approaches for the optimal placement of EVCS, including the distribution network operator (DNO) approach, the charging station operator (CSO) approach, the EV user approach, and the environmental approach with different objective functions, their combinations, and constraints. The charging procedures, charging control and management, and coordinated EV flows in the EVCS and distribution network are evaluated. In addition, alternative optimization strategies for EVCS placement with objective functions are discussed. In this review study, the effects of EV load on the distribution system, the environment, and the economy are also analyzed.