SubTel Forum Magazine #126 - Offshore Energy

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FEATURE

HOW DISTRIBUTED FIBER SENSING IS ADVANCING SUBSEA CABLE MONITORING BY MARK ENGLUND

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hen the first telegraph message sent via subsea cable was transmitted in 1868 between the UK and Canada, a lack of cable capacity and repeaters restricted the cable transmission to 2 words per minute. Although piecemeal, messages arrived quicker than the next fastest transmission method: steamships, which would require 10 days to travel between the two locations.1 Within two years, the transmission speed had already improved to 20 words per minute. Fast-forward 150 years later and subsea cables have evolved to become communication superhighways, responsible for transporting 99% of internet and cloud traffic globally across approximately 500 submarine cables that span 1.3 million kilometers of ocean floor.2 Subsea power cables, too, are looked to as a game changer in the energy sector as the solution to transmitting high-voltage electricity underwater. Use cases for subsea cables continue to develop. They play a central role in harnessing offshore energy, with impressive projects like the recently completed North Sea Link3 drawing attention to countries’ 1 https://www.iscpc.org/information/learn-about-submarine-cables/timeline-history/ 2 https://www.submarinecablemap.com/ 3 https://www.cnbc.com/2021/10/04/worlds-longest-under-sea-electricity-cable-beginsoperations.html

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SUBMARINE TELECOMS MAGAZINE

need to reap the benefits of superior ocean wind activity and tidal power generation. Given the increasing dependence the global economy has on both connectivity (internet and cloud) and power transmission, subsea cables are therefore increasingly vital, which is why it is crucial that innovations in threat mitigation keep evolving to ensure reliable delivery of critical connectivity and power to our communities. Much like the evolution of subsea cables themselves, distributed fiber optic sensing, and specifically vibration detection and ranging (VID+R) technologies, have seen rapid growth and are reaching an inflection point in adoption. Fiber sensing benefits cable operators by providing instantaneous awareness of threats across every meter of the long linear asset for the first time. This type of actionable real-time information drives clear cost savings and avoids downtime. While fiber optic sensing is increasingly being adopted for telecommunications cables, it remains a lesser-known solution for power cables. With the distributed fiber sensing (DFS) market expected to grow at a compound annual growth rate of 7.3% over the next eight years, reaching a total market value of $2,553.5 million USD by