Analysis of Synthetic Inertia Strategies from Wind Turbines for Large System Stability

In this paper, two different strategies to enhance power system stability exploiting synthetic inertia are presented and compared to assess the possibility of increasing the penetration of converter-based generation in power systems, keeping a suitable stability margin. Synthetic inertia is the emulation, carried out by converted-based generation, of the inertial response provided by rotating generators during frequency events. Two approaches are hence described, focusing on wind power. In the first approach, the primary power source is connected to the grid by a grid-following converter, and it exploits the energy content of the direct current link, suitably sized (or, with the same concept, of a suitable energy buffer available). The second approach uses a grid-forming converter model, whose features resemble more a traditional synchronous machine. The paper aims at assessing the contribution to frequency stability that can be provided by converter-based generation. The simulation results demonstrate that converter-based generation can efficiently guarantee frequency stability, thus proving that future power systems will be able to manage ever-increasing RES converter-based generation.