Indeximate’s technology leverages existing optical fibers that commonly exist in subsea power cables to collect and automatically interpret distributed acoustic sensing (DAS) data. The monitoring and analysis included key areas of the cable protection system (CPS) between touchdown and aperture, as well as inside the monopile from aperture to hang off, where installation of sensors for monitoring has long been a legacy issue for the sector.
Over the six-month period, data were collected on the cables as they were subject to typical winter storm conditions, the effects of gravity, and 7-meter-high waves. Dynamic strain measurements from DAS were taken 2,000 times per second at 10-meter intervals along the cables. Indeximate compressed the raw data in real time using its proprietary Indeximation® technology, uploaded to its cloud portal, the Scattersphere, where automated analytics extracted several long-term risk profiles for the cable, including abrasion, strain, fatigue integrity, and vibration.
Automated analysis of the data identified signatures related to cable movement, abrasion, and vibration, as well as fatigue and damage. Analyzed alongside co-registered wave and wind data, the long-term data record allows Indeximate to observe how the cables behaved in certain conditions, such as directional weather and specific wave heights, and identify where issues may emerge. These insights have the potential to identify points of failure in advance, providing time for O&M teams to develop approaches to mitigate issues and avoid disruption and downtime, which can cost operators millions.
Commenting on the ongoing monitoring work, Dr. Chris Minto, Director, Indeximate, said: “Our proprietary data compression and analysis technologies are unlocking vital insight into cable health that previously was unavailable to operators and allow us to establish health and risk profiles for all subsea power cables, helping operators avoid repair costs. We are hugely proud of our work with RWE to provide a clearer view of the condition of their cables at the Arkona wind farm in the hard-to-inspect regions inside the monopile and through the CPS, showing how weather variations affect cable health.”
Anika Borm-Schmelcher, Head of Innovation & Industrialization at RWE Offshore Wind, commented: “We have been impressed by the work Indeximate delivered to monitor our cables at our Arkona offshore wind farm. Since participating in RWE’s Innovation Competition in 2023, Indeximate and its data processing and monitoring technologies have further developed and now demonstrated their potential to deliver insight on our assets and to exploit the cloud-based resource for multiple approaches beyond cable health. The solution might finally enable RWE to better forecast the health of seabed power cables and, further in the future, to monitor the working environment of our offshore wind farms.”
Indeximate uses industry-leading proprietary data compression technology to enable the analysis of petabytes of long-term DAS data collected using optical fibers that commonly exist as part of subsea power cables, in Indeximate’s cable health monitoring Scattersphere technology.
Historical pattern and trend analysis allows the creation of years-long risk profiles, which enable cable operators to continuously assess risks to assets, understand remaining life, and benefit from early warning and detection of cable flaws. New fiber sensing and data compression approaches are enabling the offshore wind industry to reevaluate cable monitoring and the extent of insights that can be gathered on cable health, environment, and the water column.
