Delivering Specialist 220kV Subsea transition Jointing in Germany

Working alongside Equans in Germany, we delivered specialist 220kV subsea and transition joining works for the Ostwind offshore transmission system, ensuring a secure power export from offshore generation to the German grid.

Scope

This project included the installation of subsea joints on offshore export cables, the construction of transition joints between subsea and land cable sections, and the execution of all jointing activities in line with OEM procedures and international HV standards. Providing support to the wider transmission installation and commissioning programme.

Challenges

One of the key elements of work was managing the complex interfaces between the subsea and land cable systems, as they demand flawless alignment and preparation to ensure the transition jointing happened smoothly. The team had to follow strict compliance with the NKT and OEM-specific jointing methodologies alongside elevated safety and quality requirements typical of German high-voltage transmission projects. ​

Approach

To carry out the highly skilled project we deployed our senior, fully certified jointers trained in 220 kV subsea and transition jointing.​

• Use of approved tooling, materials and OEM‑validated installation processes.​
• Robust quality controls, including inspection, verification and staged sign‑off.​
• Full testing of joint performance for electrical, insulation and continuity parameters.
• ​Delivery aligned with NKT’s safety, documentation and installation standards.

Outcomes and benefits to the client

As a result our team completed a successful installation of all 220 kV subsea and transition joints, demonstrating our capability in delivering high-voltage works for major European grid projects.

• High‑reliability connections supporting secure offshore energy transmission.​
• Full compliance with safety, technical and documentation requirements.​