Cable protection helps to preserve the cables at vulnerable locations from wave and tidal action. For dynamic cables, this is typically where the cable enters and exits floating substructures and offshore substations, the touch down point, and where the cable lies exposed on the sea bed.
What it costs
About £7.7 million for a 450 MW floating offshore wind farm.
Who supplies them
Balmoral, CRP Subsea, First Subsea, MacArtney, Subsea Energy Solutions, Tekmar (including Pipeshield) and WT Henley.
Cable bend stiffener. Image courtesy of Kaylan Offshore. All rights reserved.
Cable protection systems ensure the cable is not subjected to excessive loading along the cable route.
Bend stiffeners and bend restrictors reduce the bending moments applied to cables. Connection points between cables and floating substructures use dynamic bend stiffeners. These are conical devices that limit the movement of the cable to a permitted range (dependent on the cable’s minimum bend radius). Connections between cables and fixed structures (including fixed offshore substations or the sea bed) use static bend restrictors. These are rigid devices that force the cable to follow a constant bend radius to prevent overbending.
Dynamic cables can also require tether and anchor systems to reduce the movement of the current loading on the dynamic cables at the touch down point.
Abrasion protection and touch down protection are provided by protection matting and protection sleeves. These protect the cable where it lies exposed on the sea bed, where it enters or exits the sea bed, or where it crosses other cable routes.