Design of Multiple Supplementary Controllers for Embedded HVDC Links Using a Model-Free Adaptive Control Approach

Power system stability is a fundamental requirement for ensuring reliable and secure operation of interconnected grids. Disturbances such as short circuits or generator trips can initiate or amplify electromechanical oscillations, which, if not properly damped, can compromise system integrity. In this paper, a data-driven approach known as Model-Free Adaptive Control (MFAC) is applied to the design of Power Oscillation Damping (POD) controllers for mitigating inter-area oscillation modes in large-scale power systems. Unlike traditional model-based techniques, the MFAC method does not require a mathematical model of the system, relying solely on real-time input–output data to adaptively adjust the control signal. This makes the controller particularly suitable for systems with significant nonlinearities and uncertain operating conditions. The proposed POD controllers are implemented as supplementary controllers on embedded High Voltage Direct Current (HVDC) links. Their performance is validated through two case studies: a test system composed of two HVDC links and eight synchronous generators, and a full-scale model of the Brazilian Interconnected Power System (BIPS). In both cases, the MFAC approach is applied to design POD controllers in multiple HVDC links, and the performance is compared with that of POD designs based on traditional techniques. In all evaluated scenarios, the MFAC controllers exhibit effective and efficient damping of inter-area oscillation modes. Additionally, the controllers demonstrate robust performance under large variations in power system operation.