Modeling zero-dynamics attacks on wind turbines through Laplace and z-domain representations

Zero-dynamics attacks pose a new kind of threat to distributed control systems as an attacker can cause unbounded vibrations of the plant, which can not be detected from the sampled signals via a monitoring system. This paper illustrates a zero-dynamics attack that can be carried out on a wind power system controlled by a discrete-time control law. It is shown that the response functions can be represented analytically both in the z and Laplace domains, and a novel method is also provided to reconstruct the signals in the time domain. Simulations verify the theoretical results and show that the presented method can model the continuous-time response, including the critical intersample behavior, to detect the zero-dynamics attack.