Resilient Periodic Observer-based Control for Wide Area Oscillation Damping Against Time Synchronization Attacks

The paper proposes a secure implementation of a Wide-Area Oscillation Damping Controller (WAODC) to improve the damping of low-frequency inter-area oscillations under both First-Order Time Synchronization Attacks (FO-TSAs) and DoS attacks. The proposed controller, which is based on a Luenberger observer, only requires periodic samples of the power system outputs; thus, it can be digitally implemented. Targeting to deteriorate the controller performance in damping the oscillations, the adversary attempts to block the control unit in an atypical pattern. Sufficient conditions to guarantee the damping of inter-area oscillations (i.e., stability) under FO-TSA are derived as Linear Matrix Inequality (LMI) conditions obtained from delay-dependent Lyapunov-Krasovskii functionals. In addition to the sampling period for measurements and the oscillation damping rate, the proposed design framework allows including the desired level of resilience against FO-TSAs and DoS attacks by computing the proper control and observer gains. Simulation results are also provided to confirm the effectiveness of the proposed approach.