Coordinated Inertial Response Provision by Wind Turbine Generators: Effect on Power System Small-Signal Stability of the Sicilian Network

To guarantee the small-signal stability in power systems with lower rotational inertia due to high renewable energy sources penetration, a coordinated controller exploiting the inertia of variable speed wind turbines is here proposed and assessed. In particular, wind turbines based on permanent magnet synchronous generators are considered for this scope; the rotor kinetic energy reserve and the electrostatic energy stored in the supercapacitor units interfaced to the DC-link are employed to provide the inertial response. The controllers of the individual schemes are first presented alone; then, the coordinated control scheme is derived. The impact on power system small-signal stability of these schemes is studied first on the well-known Two-Area Network, and then on a portion of the Italian transmission grid employed in the framework of the European project OSMOSE. For the considered networks, both modal analysis and dynamic simulation results, evaluated in the DIgSILENT PowerFactory environment, indicate that the coordinated synthetic inertia control scheme enhances the small-signal stability with the correct gain selection.