Adaptive Wide‐Area Damping Control for Local Oscillations Induced by Grid‐Forming Converters and Frequency‐Sensitive Loads

ABSTRACT

In high‐proportion power‐electronic‐based power systems, the dynamic interaction between grid‐forming (GFM) converters and frequency‐sensitive loads (e.g., induction motors) may induce weakly damped or even negative‐damped local oscillation modes, which seriously threaten system stability. Traditional modelling and stability analysis methods often oversimplify load dynamics and overlook the coupling mechanism between GFM control and frequency‐dependent load characteristics. Meanwhile, conventional damping controllers such as Power System Stabilizers (PSS) and POD lack robustness to operating‐point changes, parameter uncertainties, and model mismatches. To fill these gaps, this paper establishes a unified small‐signal state‐space model that integrates GFM‐controlled renewable energy, hybrid energy storage systems, and aggregated induction motor loads. Using eigenvalue analysis, participation factors, and multivariable frequency‐domain theory, this study reveals that high load factor and low motor inertia form a dangerous parameter region that triggers negative‐damping oscillations. The key oscillation mode is dominated by the active power–frequency coupling loop between GFM units and motor loads. Accordingly, an adaptive wide‐area damping controller based on improved linear active disturbance rejection control (ALC‐ILADRC) is proposed. By employing wide‐area frequency signals and an enhanced linear extended state observer, the controller can online estimate and compensate for unmodelled dynamics, parameter perturbations, and interactive disturbances. Adaptive bandwidth adjustment is further introduced to match the drifting oscillation frequency. Electromagnetic transient simulations verify that the proposed method rapidly suppresses oscillations and provides greater robustness than conventional damping controllers across various operating conditions and parameter variations.