Synchronous inertia control for wind turbines

The purpose of this paper is twofold. First, it provides a self-contained introduction to power system inertia and its emulation with a focus on wind power plants. The physical inertia of synchronous machines plays an important role for the short-term balancing of active power in AC power systems. With an increasing share of inverter-based generating units, like e.g. wind turbines, this system inertia -and its stabilizing effect - is reduced. A widely discussed solution is to integrate an emulation of the inertia in the inverter's controls. Second, the paper presents some first results on the adaption of the so called virtual synchronous machine to a wind turbine. Implications for the control of the generator system are identified, including a suggestion for limiting the inverter power, and an exemplary control design is being carried out. Simulations with simplified, generic models of the power system and an aggregated wind power plant show that the proposed Synchronous Inertia Control Scheme enables wind turbines to contribute to power system inertia in the same way a synchronous machine does.