A Smart Charging Strategy for Electric Vehicles to Increase their Hosting Capacity in Distribution Systems

Abstract

This paper proposes a smart charging strategy for electric vehicles (EVs) to increase their hosting capacity in distribution systems (DSs). Although EVs can be charged at both home and public charging stations, large percentages of EVs are charged at home. Therefore, coordinated charging of EVs at home has the potential to increase their hosting capacity in DSs. The proposed smart charging strategy is developed based on hourly extra available power (HEAP) of DSs and probability distribution functions of daily travel distance, charging duration, departure time, and arrival time. These distribution functions are constructed using survey data collected from several technical reports. The HEAP is calculated by taking the difference between maximum hourly loading capacities and hourly loads at each node. The proposed strategy is demonstrated on the IEEE 123 node test feeder through several case studies. The AC power flow is performed using OpenDSS to calculate the maximum hourly loading capacities and to check network constraints. Monte Carlo simulations are used to calculate the hosting capacity. The results show that the hosting capacity of EVs in the IEEE 123 node test feeder using the proposed strategy is approximately 43.2% larger than that of uncontrolled charging.