Optimal Power Flow-Based EV Hosting Capacity Enhancement in Distribution System

The increasing penetration of EVs can cause system instability and undervoltage, especially during simultaneous charging. Evaluating EV Hosting Capacity (EVHC) is essential to maintain system stability. This paper investigates EVHC under various conditions by incorporating EV Charging Station (EVCS) and Photovoltaic (PV) systems using the AC Optimal Power Flow (OPF) method on the IEEE 33-bus distribution network. Transformer, voltage, and thermal constraints are considered to ensure system stability. Buses with the highest voltage are used as references points for EVCS installation using DC Fast Charging Level 3. Simulations are conducted hourly over a 24-hour period. Two calculation scenarios are considered: without PV and with PV. The optimum result was obtained using 20 EVCS units, which can accommodate up to 3,656 EVs distributed across the network to reduce losses. The optimal PV installation is achieved when PV is collocated with EVCS, allowing the power output to be directly used for EV charging, resulting in a 2.78% increase in EVHC. Sunny weather provide the most favorable improvement in EVHC. The results of the study show that the AC-OPF method maintains EVHC calculations within system constraints and highlight the importance of the number and placement of EVCS and PV, as well as weather conditions, in improving EVHC.