The transition to sustainable energy requires advanced control methods as variable renewable sources like wind and solar replace conventional generation. Millions of digitally controlled devices, including electric vehicle chargers, heat pumps, and smart appliances, are being introduced into the grid. Data centres add software-dependent loads. Together, these trends are reshaping the power system into a cyber-physical infrastructure where physical devices and digital control are deeply intertwined. System reliability increasingly depends on software-controlled device coordination across all operational layers.
While cyber-physical integration enables unprecedented efficiency and flexibility, it introduces new systemic risks. Historical events underscore the stakes: inadequate situational awareness contributed to the 2003 North American blackout, and software-driven control failures have played critical roles in recent major outages. Beyond failures and malicious attacks, even benign control routines can become systemically relevant when many devices act coherently. Unintended synchronization can generate recurrent and potentially amplified oscillatory behaviour in large-scale cyber-physical energy systems. Modern power systems exhibit oscillations across a broad range of time scales. Oscillations with characteristic periods around 1 min have previously been discussed as ultralow-frequency oscillations (ULFOs) and linked to resonance phenomena in hydropower turbine-governor systems. However, resonance phenomena in classical control systems differ fundamentally from cyber-physical synchronization effects. Oscillations without external timing signals do not naturally explain patterns that remain phase-coherent over long time scales or occur reproducibly across diverse power systems. In this Article, we identify and explain a coherent 1-min oscillation in power systems worldwide caused by cyber-physical synchronization effects. The grid frequency, and thus the power balance, exhibits a highly regular periodic pattern with a period of exactly 1 min. Clock-synchronized control actions in battery-based uninterruptible power supplies (UPSs) generate periodic power-demand peaks, and this signal propagates across multiple voltage levels up to the transmission interface. The identified synchronization mechanism is not specific to UPSs or battery systems, but reflects a general property of digitally controlled devices operating with external timing signals or periodic software routines. The rapid expansion of battery storage, data-centre infrastructure and Internet-of-Things devices increases the relevance of cyber-physical risks. Decreasing system inertia makes power systems more sensitive to coherent power imbalances. The oscillation contributes to wear and tear, especially in hydropower turbines, and has motivated stricter load-frequency control requirements. Coherent cyber-physical oscillations can be mitigated directly at their source through improved control design.
Source: Hacker News · Summarized by HeadlinesBriefing