One-minute frequency disturbances from unintended synchronization in cyber–physical power systems

Electric power systems are evolving into cyber–physical infrastructures shaped by power electronics and digital control. As inverter-based generation alters system dynamics and digitalization heightens vulnerability to errors and attacks, cyber–physical coupling can also introduce subtle system-level effects. Here we show that grid-frequency time series worldwide exhibit a persistent 1-min oscillatory pattern whose origin has remained unexplained. We show that clock-synchronized control software in digitally controlled energy devices, particularly uninterruptible power supplies and battery energy storage systems, generates periodic power-demand peaks that propagate across voltage levels and can give rise to the observed pattern. The pattern amplitude has increased substantially in several grids over recent years, contributing to wear and tear in hydropower systems and motivating stricter frequency-control requirements. The rapid expansion of battery storage, data centres and the Internet-of-Things may further amplify such cyber–physical power oscillations, highlighting the need for improved control design.