Frequency stability enhancement for low inertia systems using synthetic inertia of wind power

High-level integration of renewable energy sources in power system leads to the displacement of conventional generators and consequently challenges in power system frequency stability are introduced. To mitigate the negative impact of significant wind power penetration in the grid on the frequency stability, this paper proposes supplementary control methods to implement synthetic inertia for doubly-fed induction generator (DFIG) based wind energy system during frequency excursions. Different control strategies and activation schemes are analyzed and implemented on the Western Danish renewable-based system using-real time digital simulator (RTDS) to propose the best one for the synthetic inertia controller. From the comparative simulation results, it can be concluded that the method using a combination of both the frequency deviation and derivative as input signals, and the under-frequency trigger provides the best dynamic response in term of the system frequency stability improvement.