Enhancing Renewable Energy Hosting Capacity in Unbalanced Microgrids via Empowering Smart Inverters

This article presents a coordinated planning strategy for renewable energy sources (RESs) and energy storage systems (ESSs) in unbalanced microgrids. The approach aims to mitigate voltage unbalance, reduce power losses, alleviate feeder congestion, and maximize the hosting capacity (HC) of RESs in grid-connected unbalanced microgrids. By employing smart inverter control for photovoltaic (PV) and ESS inverters, the strategy enhances the integration of additional RESs while minimizing power exchange between operational zones and the utility grid (UG). To achieve such an ambitious goal, smart inverter control functions are employed, including combined mode, volt-var (VV), volt-watt (VW) for Photovoltaic (PV) inverters, and VW for ESS inverters. The IEEE 123-bus test system, divided into six operational zones, is used as a case study, incorporating plug-in electric vehicle (PEV) demand and wind-based distributed generation (DG). A metaheuristic algorithm is developed for optimal DG and ESS deployment using MATLAB and OpenDSS. The results demonstrate significant improvements, including a 16% reduction in feeder congestion, a 150% increase in PV penetration, a 13% reduction in power losses, and decreased reliance on the UG, ensuring enhanced power quality and system reliability.