Offshore Power Cable Installation Using Empty Tubes
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Solution Overview
Problem
Conventional offshore wind turbine power cable installation methods are time-consuming and prone to cable damage due to the use of heavy armoring layers, which add weight and complexity to the process, and often require multiple vehicles for trenching and backfilling.
Innovation Solution
The method involves laying empty, lightweight plastic tubes in the seabed, which are later filled with power cables, allowing for continuous installation and reducing the need for heavy armoring, with a seabed vehicle capable of trenching and tube handling to streamline the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power cables with armoring layers are used for offshore installation, then the cable is protected when installed in the seabed, but the cable experiences substantial strain due to additional weight and the installation process becomes time-consuming
Solution Approach 1:
The solution divides the cable system into two separate components: an unprotected lightweight cable and a protective empty tube. The cable is inserted into the tube after the tube is laid in the seabed, separating the protection function from the cable itself and eliminating the weight penalty during installation.
Solution Approach 2:
The empty protective tube is laid in the seabed before the power cable is inserted. This preliminary action prepares the protection pathway in advance, allowing the cable to be installed quickly without carrying its own heavy armor during the laying process.
2Reliability
If heavy armoring layers are added to power cables, then the cable is protected during installation and in the seabed, but the cable weight increases substantially
Solution Approach 1:
The protective function is segmented from the cable and assigned to a separate empty tube structure. This allows the cable to remain lightweight during installation while still receiving protection once installed in the seabed environment.
Solution Approach 2:
An empty tube acts as an intermediary protective structure between the cable and the seabed environment. The tube provides the necessary protection and mechanical strength, while the cable itself remains lightweight and easy to handle during installation.
3Reliability
If multiple vehicles are used for trenching and backfilling operations, then the cable installation is completed with proper burial, but the installation process becomes more complex and time-consuming
Solution Approach 1:
A single seabed vehicle is designed to perform multiple functions: trenching the seabed, laying the empty protective tube, and facilitating cable insertion. This multi-functional approach eliminates the need for separate trenching and backfilling vehicles, simplifying the overall installation system.
4Reliability
If conventional trenching and backfilling processes are used, then the cable is properly buried in the seabed, but the installation process is time-consuming
Solution Approach 1:
The empty protective tube is laid in the seabed in advance, creating a pre-prepared pathway that eliminates the need for time-consuming backfilling operations after cable installation. The tube itself serves as the protective burial structure.
Solution Approach 2:
The backfilling step is extracted and eliminated from the installation process. Instead of digging a trench, laying cable, and then backfilling, the system uses a pre-laid empty tube that requires no backfilling, significantly reducing installation time.
Data Source
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AI summary
A method is proposed for offshore installing of power cables for wind turbine installations, wherein the power cables are installed by use of empty tubes between several offshore positions, e.g. between wind turbine foundations and/or a substation, wherein at least one empty tube is installed in or above a seabed. The method replaces laying of heavyweight armored power cables by laying of empty tubes, thus simplifying power cabling and the underlying logistics.