Solutions for cable damage avoidance in the vicinity of offshore foundations
taking into account Fluid-Structure-Soil Interaction (CableProtect)
The challenges of climate change demand a robust energy transition, with offshore wind energy as a crucial component. Ensuring the reliability and efficiency of offshore wind farms is vital. Recent occurrences of underwater power cable damage near wind turbines have led to failures, uncertainties in planning, and substantial repair costs. These damages are attributed to hydrodynamic processes around the seabed foundation structures of wind turbines. These processes induce cable dynamics due to wave and current forces and result in sediment redistribution and scour formation, impacting cable structural integrity. Typically, rock protection layers are used to prevent scour, but cable movement on the rocks causes abrasion, damaging the cable protection system (CPS) and the cable itself if not promptly addressed.
This project aims to enhance the reliability and competitiveness of offshore wind energy, supporting the broader energy transition. To achieve this, it’s crucial to gain a comprehensive understanding of cable dynamics at the wind turbine foundation connections. This understanding will help identify the root causes of cable-related issues, considering fluid-structure interaction (hydroelasticity) and fluid-soil or structure-soil interaction (sediment redistribution, scour formation). By doing so, we can develop solutions to assess cable structural integrity and implement methods to reduce dynamic cable loads, ultimately prolonging the power cables’ service life.
Schematic representation of the power cable connection to a monopile foundation and the relevant environmental conditions.
DST e.V. acts as the project coordinator and as an active project partner. Initially, a condition analysis is carried out to determine the environmental conditions, the wind farm characteristics and the structural properties of the cables and foundation structures. A thorough damage analysis will be done and suitable reference conditions and test matrices are defined for subsequent modeling and simulations.
Furthermore, DST undertakes physical modeling of subsystems and the cable connection as an integrated system. Additionally, DST e.V., ESOS Wind, and Uni Siegen engage in numerical modeling and focus on Fluid-Structure Interaction (FSI) and Fluid-Particle Interaction (FPI). This modeling helps us assessing the importance of hydroelasticity and FPI in understanding sediment redistribution and scouring processes within the cable connection area. FSI and FPI are integrated through suitable interfaces to capture the dynamics of fluid-structure-soil interaction.
The project reaches its conclusion with the development of comprehensive solution approaches. This includes the formulation of calculation methods for preliminary design, exploring alternative cable connection designs, providing recommendations for evaluating structural integrity, and creating a comprehensive design guide.
The project is funded by the German Federal Ministry for Economic Affairs and Climate Action under funding number 03EE2059A.
September 2023 – August 2026
Dipl.-Ing. Jens Ley
Tel.: 0203 / 99369-30
Dr.-Ing Wenjing Lyu
Tel.: 0203 / 99369-31
Active project partners:
Entwicklungszentrum für Schiffstechnik und Transportsysteme e. V. (DST)
ESOS Wind GmbH (ESOS)
Universität Siegen, Lehrstuhl für Geotechnik (USG)