Offshore Wind Foundation Cable Routing Without J-Tubes

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Solution Overview

Problem

The existing methods for guiding submarine cables from offshore wind turbines to the seabed are complex and labor-intensive, particularly when using J-tubes, which can cause additional shaft loads and are prone to damage from ship impacts and vegetation, and the extraction of cables from plugged hollow structural elements is challenging due to precise assembly requirements and grouting issues.

Innovation Solution

A cable routing arrangement that allows the submarine cable to exit through a cable bushing on the outer lateral surface of the hollow structural element, positioned radially from the foundation, reducing load from current forces and enabling cable exit above 5m height without protection, using a radial cable routing arrangement and support elements to restrict movement and secure the cable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If J-tubes are used to route submarine cables from offshore facilities to the seabed, then cable routing is achieved, but additional wave loads are generated and the structure is vulnerable to ship impact and vegetation damage

Engineering Contradiction:
Improvecable routing capabilityVSAvoidstructural vulnerability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention extracts the cable routing function from the J-tube structure and relocates it to the foundation structure itself. The submarine cable is routed through the hollow interior of the foundation, eliminating the separate J-tube component and its associated vulnerabilities to wave loads, ship impact, and vegetation damage.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If hollow structural elements are assembled with slight twisting at the installation site, then assembly flexibility is improved, but cable penetration alignment becomes impossible

Engineering Contradiction:
Improveassembly flexibilityVSAvoidcable penetration alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention incorporates cable penetrations directly into the foundation structure during the manufacturing process, ensuring precise alignment is built-in from the start. This preliminary action eliminates the need for post-assembly alignment adjustments and maintains both assembly flexibility and penetration precision.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If annular space between hollow structural elements is grouted, then structural stability is improved, but cable extraction becomes complex and time-consuming

Engineering Contradiction:
Improvestructural stabilityVSAvoidcable extraction complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The invention segments the foundation into modular hollow structural elements that are assembled together. The cable penetrations are positioned above the annular spaces between these elements, allowing the annular spaces to be grouted for structural stability while the cable penetrations remain accessible for cable routing without requiring complex extraction through grouted sections.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If submarine cable is routed out of foundation above 5m height, then cable protection from current forces is improved, but cable stress from current forces increases

Engineering Contradiction:
Improvecable protection from currentsVSAvoidcable stress from currents
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The invention changes the routing path of the submarine cable from a vertical exit above the foundation to a horizontal path along the outer surface of the foundation. The cable is guided radially outward from the cable penetration to the seabed, keeping the cable close to the foundation structure and minimizing exposure to current forces while avoiding the need for cable protection systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4237625B1Offshore wind energy system
Publication Date: 2024.11.20 RWE OFFSHORE WIND GMBH
  • EP4237625B1 patent drawingFigure 1
  • EP4237625B1 patent drawingFigure 2
  • EP4237625B1 patent drawingFigure 2a~2b

AI summary

The application relates to an offshore wind energy system (100, 200, 300, 400, 500), comprising a foundation (102, 202, 302, 402, 502) having a first hollow structure element (106, 206, 306, 406, 506) with a first circumferential wall (105, 205, 305, 405, 505) extending in the longitudinal direction, there being arranged in the first wall (105, 205, 305, 405, 505) a cable feedthrough (126, 226, 326, 426, 526) which penetrates the first wall (105, 205, 305, 405, 505), and further comprising at least one cable-routing arrangement (104, 204, 304, 404, 504) extending in the radial direction and arranged on an outer lateral face of the first wall (105, 205, 305, 405, 505) of the first hollow structure element (106, 206, 306, 406, 506), configured to route a submarine cable (118, 218, 318, 418, 518) exiting the cable feedthrough (126, 226, 326, 426, 526) from the cable feedthrough (126, 226, 326, 426, 526) to an underwater ground surface (122, 222, 322, 422, 522).