Impedance-Based Stability Analysis for Weak Grid Interactions

Wind parks can interact with weak AC grids, potentially causing instability. This paper presents the use of Impedance-Based Stability Assessment for a type IV wind park connected to a weak grid. The generic EMT-model is used for representing the wind park. The results show that type IV wind turbines can interact with weak grid in supersynchronous frequencies, given the behaviour of its impedance in that range. Simulations in time-domain are used to validate the results. Bode Plot, Nyquist Criterion and the Vector Fitting algorithm were used to identify the instability and the frequency where it occurs.