EV Hosting Capacity and Voltage Unbalance: An Australian Case Study

The widespread adoption of residential electric vehicles (EVs) will result in larger voltage drops due to the extra demand. Since most residential EV chargers are single-phase, they might also contribute to voltage unbalance which, in turn, can make voltage drop issues on certain phases worse. This paper investigates the extent to which voltage unbalance affects the EV hosting capacity of distribution networks using a Monte Carlo-based time-series analysis to capture the uncertainties of EV location, charger size, and charging behavior. Using a realistically modeled Australian MV-LV network with 1,300+ customers, results show that with increasing EV penetrations, the voltage unbalance keeps increasing too, even for 100% EV penetration. Moreover, it is demonstrated that large voltage unbalance significantly limits EV hosting capacity, suggesting the need for considering balancing strategies when possible.