Fast Frequency Control of Low-Inertia Hybrid Grid Utilizing Extended Virtual Synchronous Machine

Massive integration of renewables e.g., wind, pv and energy storage in hybrid energy systems introduce new challenges in terms of frequent control due to the inherent low inertia characteristic of non-synchronous generators (NSG). In this paper, an extended virtual synchronous machine (VSM) control strategy is proposed to provide better frequency support in the hybrid low-inertia grids. This approach is realized by adding a fast frequency response (FFR) droop block to the VSM control of power converter. By applying the proposed control model, the power converters interfaced energy storage systems (ESS) are enabled to emulate the dynamic behavior of a synchronous machine and provide inertia for the grid. Furthermore, compared to the conventional VSM, which, just behaves like a synchronous machine, the proposed control approach provides better frequency support. Simulation results for an RMS study in DIgSILENT PowerFactory show the performance of the proposed control in a hybrid low-inertia grid.