Determining Maximum Hosting Capacity of Electric Distribution Systems to Electric Vehicles

Abstract

This paper proposes a voltage constrained-based approach to determine the maximum hosting capacity of electric distribution systems (DSs) to electric vehicles (EVs). The continuous growth in penetration level of EVs in DSs increases the challenges to allocate power system resources. Determining the maximum hosting capacity of EVs in DSs without violating voltage constraints has a potential to handle these challenges. In this work, the maximum hosting capacity of DSs to EVs is determined-under both uncontrolled (actual) and controlled charging scenarios-ensuring that voltage requirements are not violated. The maximum hosting capacity of EVs under the uncontrolled charging scenario is estimated based on load profile of EVs and hourly extra available power (HEAP). EV load profiles are constructed using probability distribution functions of daily travel distance, 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 differences between the maximum hourly loading capacities and hourly loads at each node. For the fully controlled charging scenario, daily extra available energy (DEAE) of DSs and daily required energy to charge EVs are used to estimate the maximum hosting capacity of DSs. The DEAE of a distribution system is estimated using the HEAP. The proposed approach is demonstrated on the IEEE 123 test feeder through several case studies. OpnDSS is used to calculate the HEAP and to check the voltage constraints. Monte Carlo simulations are used to calculate the expected maximum hosting capacity. The results show that the maximum hosting capacities under uncontrolled and controlled charging scenarios are 438 and 1510 cars respectively.