A Reduced-Order Robust Wide-Area Damping Control for Wind-PV-Thermal-Bundled Power System Considering Operational Uncertainties and Communication Resilience

The wind-photovoltaic-thermal-bundled power system (WPTBS) comes with a wide range of potential grid applications and provides an efficient way to export bulk amount of power under high intermittency of wind and photovoltaic (PV) resources. This increasing penetration alongside distant power transmission, however, may cause detrimental impacts on low-frequency oscillations (LFOs), eventually threatening the stability of WPTBS. In this prospect, installing a wide-area damping controller (WADC) is proven to be efficient in suppressing LFOs but the uncertainty related to varying operating points, the time delay involved in transmitting a wide-area signal, and the possibility of remote signal disconnection may compromise the damping capability of a WADC. Following that, the proposed study presents a reduced-order robust wide-area damping controller (RWDC), injected into the wind turbine system, to stabilize the LFOs in the WPTBS while accounting for operational uncertainties, time delays, and communication failure. At first, the uncertainties are characterized in the form of polytope vertices, where each vertex represents a linearized model corresponding to a distinct operating condition. A two-stage linear matrix inequality (LMI) approach is then adopted to determine the design parameters of reduced-order RWDC, which simultaneously stabilizes the entire uncertain model by minimizing the
$H_{\infty }$
norm and ensures closed-loop stability via parameter-dependent Lyapunov functions. Finally, using small-signal analysis and extensive simulation results, the effectiveness of the controller is confirmed under different operating scenarios, including critical and unstable oscillation conditions, followed by a comparison with existing methods.