Fibre-Optic Wind Monitoring of Overhead Powerlines for Smart and Resilient Power Grids

Dynamic Line Rating (DLR) is a method employed by grid operators to maximise electrical use of powerlines. This requires detailed knowledge of conditions of the powerlines themselves, and also environmental conditions at high spatio-temporal resolution. Wind is particularly interesting as it both cools the conductor and induces conductor motion. Under certain conditions, wind excitation can lead to large-amplitude instabilities such as conductor galloping which can cause damage to the power line. Recent advances in distributed fibre-optic sensing (DFOS), particularly Distributed Acoustic Sensing (DAS) enables continuous monitoring of conductor movement over hundreds of kilometres of optical ground wire (OPGW) or phase conductors equipped with optical fibres, offering unprecedented spatial resolution for infrastructure monitoring.

In this contribution, we present a methodology to exploit conductor vibration measurements obtained via DAS to infer wind velocities and detect incipient galloping events. These measurements thus provide actionable environmental information for transmission grid operation.

A key processing step is the extraction of harmonic components from the vibration spectra. Aeolian vibrations and galloping manifest in distinct frequency bands and modal structures. By performing automated spectral peak detection and tracking of harmonic modes, we derive robust features that are sensitive to wind speed via Strouhal-type relationships, while also capturing changes in mechanical boundary conditions. We present here first results of two installation on OPGWs (15km and 55km) the mountains of central Norway during the winter of 2025/2026.

Furthermore, we demonstrate that galloping events can be identified through the emergence of low-frequency, high-amplitude oscillations with characteristic harmonic signatures. Real-time monitoring of these spectral features enables early warning of critical events, supporting proactive grid operation and risk mitigation. The ability to monitor such phenomena continuously along entire transmission corridors represents a significant advancement compared to point-based sensor systems.

By improving the estimate of wind conditions and enabling early detection of extreme loading events, this methodology directly supports Dynamic Line Rating and more efficient utilisation of existing transmission infrastructure. This contributes to the energy transition by increasing grid capacity, facilitating renewable integration, and enhancing the resilience of critical energy systems without the need for extensive new construction.