Islanding Control of a Distributed Generation Unit´s Power Conversion System to the Electric Utility Grid

This paper addresses the design issues of a power conversion system (PCS) with regards to distributed generation (DG) and intentional islanding; in particular, control algorithms with active islanding detection and re-closure schemes for the inverter(s) that directly interface the PCS to the utility grid. The proposed control strategies and new active detection and reclosure schemes in this paper allows for fast disconnect times, a zero non-detection zone, and autonomous operation from the grid. The detection and re-closure schemes work with the switched-mode operation of the control to permit the PCS to continuously supply power to the loads. The control, detection and re-closure algorithms are compared to other schemes and verified through simulation