However, as deployments increase (in 2017, a record-breaking 4,331 megawatts were installed), there is also increasing pressure on operators to significantly enhance the robustness of the supporting infrastructure for their wind farms. In particular, there is a pressing need to increase the security and optimise the maintenance of the crucial cable networks that control offshore wind farms and transmit power back to shore.
These cable networks are vital – but they are also vulnerable and expensive to repair when something does go wrong. And the threats to these undersea cables are many and varied.
These cables are designed to be in place for a long time, but the sea bed is a hostile environment. Although cables are buried, seafloor currents can erode the protective layer of sea bed – exposing cables to the sea. This causes cables to drift, causing strain and damage that can ultimately result in the cable breaking through fatigue. Cables may also suffer electrical damage caused by arcing if the cable insulation fails. And of course, there is the risk of cables being damaged accidentally in a ‘strike’ incident.
Cable arcing event displaying clear acoustic signature in DAS data, as displayed on the HWI software suite interface.
Ultimately, as offshore wind becomes a more established source of power for national grids, operators need smarter, faster ways to manage and reduce the risks on these vital networks. They need to be able to detect, locate and deal with failures and cable arcing events at the earliest possible stage.
DAS technology is well placed to provide just this insurance for offshore cable networks – giving operators real-time visibility of the integrity of their offshore networks. All of the threat events that operators care about have clear, recognisable acoustic signatures which can be detected by DAS, enabling operators to detect, classify and act on cable integrity events with confidence.
As investment in offshore wind continues to grow, operators, energy providers and technology vendors need to do more to protect that investment. Although subsea cable networks are very much the ‘unseen’ part of offshore wind farms, they are also the most vulnerable.
As such, the industry needs to adopt a more holistic view of the whole system of offshore wind, which recognises the threats and importance of the supporting cable infrastructure. All stakeholders must come together to optimise the safety of the cable networks and management platforms that make offshore wind possible.