JIPS

Joint Industry Project

Cable 2

STATIC CABLE FOR OFFSHORE WIND TLP

Initiative

In the Cable 1 JIP a fully operational simulation model was developed for assessing the ultimate life and fatigue life of a free hanging electrical cable under the floating offshore wind turbine. In the sequel Cable 2 JIP, work will continue towards developing the required technology readiness level for real projects.

objectives

The main objective of the project is to develop the required subsea inter‐array cable technology for the rapidly developing offshore renewable industry. As evidenced by insurance claims and recent experience from offshore wind farms, there is still a lot to be gained for subsea electrical cable technology. Overall, there is a strong need to de‐risk the subsea electrical cables and to bring down the levelized cost of energy (LCoE).


Deliverables

  • A new generation subsea inter‐array cable with improved fatigue properties. The new subsea inter‐array cable will retain the attractive features of the present generation cable, including its competiveness compared to alternative solutions. The improvement of the new cable is obtained by corrugated aluminium sheathing, which will reduce the bending stiffness as well as the stress levels under cyclic loading. The modern design of thecable allow for rapid offshore installation and repair, without the complications of ‘dirty tar’ or other difficult to handle materials. The cable will be produced in long length up to several hundreds of kilometres for up to 66 kV application.
  • The project will fill in the knowledge gaps for design life prediction for free spanning subsea electrical cables in exposed offshore dynamic application. Although the technology exists in principle (e.g. in Orcaflex or Shear7), the large uncertainties prevents the potential cost saving that can be achieved for the electrical cables. The main knowledge gaps that will be addressed in the project are: more accurate dynamic response calculations in the time domain, more accurate VIV predictions and industry qualified fatigue resistance tests for the electrical cable. The project aims at achieving TRL 5‐7, which is substantially above current TRL 3‐5.

Activities and planning

The project will be structured as a normal joint industry project and is divided into 5 main work packages plus one additional work package for JIP management:
WP 1: Development of next generation cable (TKF)
WP 2: Design of cable system (Bluewater)
WP 3: Development of cable VIV tool (MARIN)
WP 4: Development of cable monitoring system (MARIN)
WP 5: Offshore site test of cable under a CALM buoy (contingency)
WP 6: Management & Coordination (MARIN)