Coordination of electric vehicles charging in the distribution system

As the environmental awareness has become crucial in 21
^st
century, large penetration of electric vehicles (EVs) is expected in near future. However, integration of these vehicles in the existing distribution system will not be an easy task. Uncoordinated and random charging would cause problems such as overloads, voltage deviations and increased power losses. Thus, electric vehicle charging has to follow some optimal charging pattern that will reduce negative impact on the utility grid. This paper analyzes problems caused by EVs charging and proposes an optimal charging solution for coordinating charging of large number of electric vehicles that aims to improve voltage profile. Therefore, three charging modes have been considered: uncoordinated, dual-tariff and coordinated charging. It is shown that the proposed coordinated charging solution has improved voltage profiles and reduced negative impact on the grid. All calculations are done in GAMS (General Algebraic Modeling System) environment, using CONOPT solver.