French project takes dynamic subsea cable monitoring tech to sea trials

A sea trials campaign for monitoring dynamic subsea power cables was conducted from 1 to 6 July in the Bay of Douarnenez, France. The trials are part of the HT-20MW project that aims to design, test, and certify a high-voltage rotating mechanical and electrical connection for a 20 MW floating wind turbine.

The sea trials focused on simultaneously testing different monitoring technologies on a real cable in offshore conditions. The cable was deployed in a lazy-wave configuration from an anchored vessel, TSM Penzer. The trials aimed to record its deformed shape over time, measure the local curvature radius, and identify stress peaks.

Five companies have taken part in the trials to test their sensor solutions in real-life conditions: CADDEN (France) in partnership with Sonardyne (UK), FEBUS Optics (France), NKT (Sweden), and Viper Innovations (UK). A sixth company, Exail (France) was contracted to monitor the cable shape with a multibeam echosounder as a reference for the trials.

France Energies Marines oversaw the sea trials and recorded the position and movements of the boat and of the cable hang-off, as well as cable tension.

The results of the trials are expected to be published in early 2025.

The campaign is part of a broader effort to enhance the reliability and monitoring of dynamic subsea power cables, which are critical for the development and maintenance of floating offshore wind farms, according to France Energies Marines.

The HT-20MW project, which is supported by the sea trials of dynamic cable monitoring, is funded by ADEME, Corimer, BPI France, and the France 2030 program. The project is led by Eolink, with partners France Energies Marines, Ifremer, Everaxis, Windglaz, and Université Gustave Eiffel.