Study on the proportional allocation of electric vehicles with conventional and fast charge methods when in distribution network

This paper studies the hierarchical classification of electric vehicles (EV) by analyzing the differences of charging behaviors of different types of EVs. According to the different proportions of conventionally-charged EVs and fast-charged EVs, four indexes (the increment of peak load, the duration of peak load, the maximum smoothing index of load curve and the average smoothing index) are proposed to evaluate the impact on the distribution network. Then a method is established to configure the proportion of EV in different charging methods. Finally, based on the field data of a distribution network and the IEEE-34 node example, the optimal proportion of EV in different charging methods are made combined with the Monte Carlo simulation of charging load. Results show that suitable ratio of EV with different charging methods can make the load curve smoother and the grid´s difference between peak and valley loads decrease significantly.