Resilient fixed-order damping controller for low-frequency inter-area oscillations in power systems under communication failures

Abstract Low-frequency inter-area oscillations (LFOs) pose a critical challenge to small-signal stability, affecting the reliable operation of interconnected power systems. These oscillations can reduce tie-line power transfer capability and weaken overall system performance. This paper proposes, for the first time, a robust fixed low-order two-input single-output (TISO) damping controller based on dual wide-area signals to mitigate the effects of communication failures and time delays on system stability. Inter-area modes can be effectively observed from multiple locations and controlled from a single point, which motivates the use of a wide-area damping controller (WADC). Communication failures and time delays are important challenges in wide-area control, and delays are modeled using the Padé approximation. The controller is designed by optimizing key performance measures, such as the $$H_{\infty }$$ norm, spectral abscissa, and complex stability radius, to improve the robustness and stability of the system under uncertain conditions. The proposed controller improves system resilience by using the two most observable wide-area signals associated with critical inter-area modes. Kundur’s 11-bus system and the IEEE 39-bus test system are used to validate the proposed method. Simulation results show that the controller effectively improves the damping of inter-area oscillations under normal conditions and maintains stable performance even in the presence of communication failures and delays.