CPS defect on inter-array cables hits RWE’s UK offshore wind farm

One more developer has joined the battle with inter-array cable issues that continues across the offshore wind industry, as RWE and its consortium partners behind an offshore wind farm in the UK have discovered a defect in the cable protection system on multiple locations along several inter-array cable lines.

According to Notices to Mariners for the offshore wind farm site, a defect of the cable protection system (CPS) on an inter-array cable was discovered several months ago. A subsea survey carried out in February then found evidence of sections of cable exposure in ten areas over seven cable routes.

While remedial protection work was initiated a few months later, another survey performed in May discovered further 19 locations that have the same defect.

The first inter-array cable CPS fault at the Galloper offshore wind farm was identified on the scour protection around one of the project’s wind turbine foundations, an Achilles’ heel of the CPS with which Ørsted is also having trouble on multiple offshore wind farms.

Ørsted recently revealed that the issue at its offshore wind farms occurs when the CPS moves across the scour protection, abrading the CPS and in the worst-case scenario causing the cables to fail.

Whether RWE is having the exact same issue is left to be seen. The company has confirmed to our sister site OffshoreWIND.biz that it is looking into the potential CPS issues across its offshore wind farms, but has not provided specific details on the matter.

“We are aware of the specific issues with CPS and have been analyzing potential issues on our fleet of offshore wind parks”, a spokesperson for RWE told OffshoreWIND.biz.

“We have identified a limited number of locations in rather new assets, including Galloper, that may be affected. We have already identified and are taking steps to introduce remedial measures that will not have a material impact on RWE”.

Meawhile, Ørsted is coming up with ways to remedy the losses brought by the CPS issue and to protect the inter-array cables from further degradation and failures.

The company now plans to implement a “band aid” solution, instead of an initially planned two-phased approach that would have involved placing a second layer of rocks and replacing the exposed cables.

The new measure would see divers placing a cover over the cables that could potentially eliminate the need for all of the damaged cables to be fixed or replaced, and could reduce the financial impact that has been estimated to be around €403 million.

Cable failures are the most frequent of issues with offshore wind farm components and account for the most losses. As more and more offshore wind farms are now entering operations and numerous new and big projects are set to be built, the industry is now increasingly trying to prevent cable failures and minimise their impact.

While cable failures are occurring more often with export cables, which also bear greater financial impact, inter-array cables are not much risk-free either. According to data from GCube Insurance, this component type comes after export cables and foundations in terms of frequency and financial severity of component failures.