Design and implementation of a virtual islanding controller for renewable energy communities

The increasing penetration of Renewable Energy Sources (RES) in distribution networks calls for advanced flexibility services to support system operation. Among emerging solutions, Virtual Islanding (VI) has been proposed as a promising service; however, a dedicated control architecture enabling Renewable Energy Communities (RECs) to effectively provide VI has not yet been systematically addressed in the literature. This paper fills this gap by defining a novel control architecture specifically designed to coordinate the distributed resources of a REC during a VI request from the Distribution System Operator (DSO). The proposed coordinated two-level control framework combines a higher-level optimization-based energy management strategy, which schedules available flexibility resources over the VI time horizon, with a lower-level real-time controller that compensates for load and RES forecast deviations to ensure power balance. The proposed architecture is implemented and validated through detailed simulations on a representative REC providing the VI service in a 4.5-hour time window over a reference day. Results show the effectiveness of the proposed architecture, where the higher-level control provides suitable management of dispatchable resources while the FLL provides compensation for fast power variations. More quantitatively, a root-mean-square imbalance of 0.027 MW (0.28% of the total REC peak load), a maximum load imbalance of 0.224 MW (2.3% of the total REC peak load)) and an energy imbalance of 0.005 MWh (0.23% of the maximum RES shared energy of the considered test case) have been achieved in the proposed simulations, thereby ensuring effective real-time VI operation throughout the scheduled horizon. These findings demonstrate the technical feasibility and effectiveness of RECs in providing VI as an innovative distributed flexibility service.