Activation schemes of synthetic inertia controller on full converter wind turbine (type 4)

One of the challenges in future energy systems is the massive use of high power converters that decouple new energy sources from the AC power grid, disabling natural frequency response. This situation decreases the total system inertia affecting the ability of power system to overcome system frequency's disturbances. It has been established by the wind power industry a controller to enable inertial response on wind turbines generators (WTG) enabling the frequency response: Artificial, Emulated, Simulated, or Synthetic Inertia. However, there is a clear lack of knowledge about activation scheme used for these controllers and how they work in practical manner. This paper proposes three activation schemes for synthetic inertia on WTG based on full converters: (i) Continuously Operating triggering, (ii) Under-frequency Trigger and (iii) Maximum-Frequency Gradient Trigger. Simulations over a test system are used for a preliminary evaluation of the proposed activation schemes. The main contribution of this paper is the three schemes to activate the synthetic inertia controller and the simulations results that demonstrate under-frequency trigger provides good dynamic response.