An improved dynamic mode decomposition for real‐time electromechanical oscillation monitoring in power systems: The impact of ultra‐low frequency modes and its removal strategy

Abstract The growing complexity of power systems, driven by the increasing use renewable energy sources, necessitates efficient real‐time monitoring electromechanical oscillations, which is crucial for enhancing grid security. Dynamic Mode Decomposition (DMD) a promising data‐driven method addressing this challenge made possible system digitalization. However, DMD implementation faces unresolved issues, including impact ultra‐low‐frequency modes (ULFM) on accuracy due to trends caused their excitation. While larger data windows can mitigate this, they slow down oscillation estimation. ULFM characteristics remain poorly studied. This study conducts comprehensive analysis and proposes solution combining with high‐pass filter counter ULFM's adverse effects accuracy. allows reduction in DMD's window size, significantly improving computational efficiency. Simulations three test systems demonstrate that enhanced offers faster computation superior compared traditional method.