Grid Frequency Regulation Based on Point of Common Coupling Angle Deviation Control of Distributed Energy Resources With Fully Active Hybrid Energy Storage System

This article proposes an architecture that controls hybrid energy storage system (HESS) integrated photovoltaic distributed energy resource (as a dc-microgrid) and achieves grid frequency regulation by capturing voltage angle deviations (Δδ) at the microgrid point of common coupling (PCC). The proposed architecture is an optimal controller that augments the conventional bidirectional control of the HESS and serves as a supervisor to ensure optimal dispatch of HESS for inertial support. The architecture is tested on a modified IEEE 123 bus power distribution system, where three dc-microgrids are integrated at different buses using three-phase d-q voltage source inverters. Power-sharing determined by the minimization routine is based on the relative angle sensitivity at PCC. Unlike, frequency-droop approach the proposed architecture shares power depending on the proximity of fault/dynamics location from the microgrid of interest. Both inertial and secondary frequency responses are supported by individual dc-microgrids by locally detected (Δδ) deviations and the demonstration shows that the architecture shows an improvement of more than 20% in comparison to the conventional frequency-droop method.