220kV Cable Protection for Borssele Offshore Wind Farm Expansion
The Client
The client is a Dutch infrastructure EPC contractor, renowned for delivering complex offshore power grid projects in the North Sea. Managing the expansion of the Borssele wind cluster required them to navigate not only extreme marine conditions but also strict regulatory requirements set by European offshore grid operators.
The Challenge
In 2025, our team was commissioned to support this critical expansion phase. The project faced severe environmental constraints:
Seabed Scour & Free-spans: The North Sea’s mobile sand waves caused significant seabed morphology changes. Without protection, the heavy 220kV export cables risked becoming suspended, leading to vortex-induced vibrations (VIV) that could snap the cable.
Critical MBR Requirements: Due to the massive diameter of the high-voltage cables, maintaining a strict Minimum Bend Radius (MBR) was non-negotiable. Any deviation during the cable-pulling phase through the J-tube would result in internal damage to the insulation layers.
Operational Longevity: The client required a design life of 30 years with minimal subsea intervention, demanding materials that could withstand the constant salinity and high-energy wave climate of the North Sea.
The Solution
We moved beyond standard protection, delivering a bespoke Bend Restrictor system integrated with our field-proven engineering expertise:
Precision-Molded Geometry: Each BR segment was engineered using CNC-machined polyurethane to match the exact diameter of the 220kV cable, ensuring an interlocking mechanism that prevents over-bending while allowing for essential cable flexibility.
Advanced Load Distribution: Our design incorporated stainless steel (Grade 316L) hardware within the internal locking structure, providing the necessary shear strength to distribute dynamic loads across the turbine foundation interface.
Full Lifecycle Qualification: We conducted rigorous Full-Scale Bending Tests and Fatigue Life Analysis in our lab to verify that the protection system would withstand 30 years of cyclic loading in the North Sea environment, supported by comprehensive Material Test Reports (MTRs).
The Result
Flawless Installation: The installation at the J-tube exit was completed within the planned 48-hour window, with ROV (Remotely Operated Vehicle) feedback confirming a perfect alignment between the BR and the foundation transition piece.
Reduced O&M Costs: By preventing fatigue damage at critical cable entry points, the client projected a 20% reduction in planned underwater inspection frequency over the next decade.
Strategic Trust: This deployment has positioned our company as a preferred supplier for upcoming North Sea offshore wind tenders, with the client specifically citing our “technical transparency and engineering-led design approach” as the deciding factor in the partnership.
Beyond Bend Restrictors: Comprehensive Cable Protection Solutions
The success of the Borssele project is a testament to our specialized approach to subsea asset integrity. Beyond our bespoke Bend Restrictor systems, we provide a full portfolio of Cable Protection Systems (CPS) designed to secure high-voltage assets throughout their entire operational life.
