Impact of Semi-fast Charging Stations on Unbalanced Power Distribution Systems Integrated with PV Systems

Rooftop photovoltaics (PVs) and electric vehicles (EVs) have gained significant attention recently due to their key factor of decarbonising the electricity and transportation sectors. However, introducing new charging stations and increasing PV integration into power distribution systems can bring new operational challenges, including overvoltage and voltage unbalance. Therefore, this paper investigates the impact of EVs connection on an unbalanced power distribution system considering local voltage control of PV inverters. Several cases were studied using the unbalanced IEEE 37-node test feeder over a 24-hour simulation period. The unbalanced load flow calculation results argue that EVs connection can increase the severity of voltage unbalance, and PVs connection can potentially reduce the voltage unbalance issues. On the other hand, the reactive power capability of a PV system does not necessarily minimise power losses, especially at a high penetration level of PV.