Adaptive Active Damped Resonance Suppression Strategy Considering the Frequency Coupling Characteristics of Grid-Connected Oscillations of Photovoltaic Power Stations

This paper addresses the wide-frequency oscillation caused by grid-connected large-scale photovoltaic power stations (PV Power Stations). Based on the complex topology of actual power grid, a grid-connected photovoltaic power station system model is established. Using the Nyquist stability criterion, the “oscillation risk region” of the interconnected system is identified. An improved adaptive active damping method is proposed, considering frequency coupling characteristics induced by phaselocked loop (PLL) control. An adaptive cascade trap is set to provide full-frequency positive damping, with phase angles between ± 90°, adapting to changes in grid operation mode and achieving adaptive oscillation suppression. PSCAD/EMTDC simulations demonstrate the proposed method's better dynamic performance and harmonic suppression effect, reducing resonance frequency shift risks.