Adjustable Submarine Cable Bushing for Offshore Wind Turbine Foundations

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Solution Overview

Problem

Offshore wind turbine submarine cables are frequently damaged at sea cable bushings due to sea currents and seabed changes, such as scours and shifting dunes, which affect the cable's vibration and length, leading to instability and damage.

Innovation Solution

A submarine cable bushing with an adjustable passage slot extending predominantly parallel to the foundation pile's longitudinal axis, allowing the cable to be inserted at multiple heights, reducing stress and damage by accommodating seabed changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the submarine cable bushing is positioned at a fixed height above the seabed, then the cable passage is stable during installation, but the cable becomes vulnerable to damage when seabed changes occur due to scours or shifting dunes

Engineering Contradiction:
Improvecable damage preventionVSAvoidseabed change accommodation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The submarine cable bushing is made adjustable along the feed-through slot, allowing it to be repositioned vertically. This dynamic adjustment capability enables the bushing to adapt to seabed changes such as scours or dune shifts, maintaining optimal cable passage height and preventing cable damage while preserving installation stability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The vertical position parameter of the submarine cable bushing can be changed along the feed-through slot. By adjusting this parameter, the system responds to seabed elevation changes, ensuring the cable passage remains at an appropriate height above the seabed to prevent damage from currents and mechanical stress

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the submarine cable bushing is positioned higher above the seabed to avoid damage, then cable protection improves, but the cable length increases and vibration behavior deteriorates

Engineering Contradiction:
Improvecable damage from currentsVSAvoidcable vibration behavior
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The adjustable bushing position allows optimization of the cable's freely hanging length. By positioning the bushing at the appropriate height along the feed-through slot, the system minimizes cable vibration while still providing sufficient clearance from the seabed to protect against current-related damage

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If a fixed submarine cable bushing design is used, then the structure is simple and easy to manufacture, but the cable passage cannot adapt to varying seabed conditions

Engineering Contradiction:
Improvebushing structure simplicityVSAvoidseabed condition adaptation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The bushing is designed with adjustability along the feed-through slot, adding minimal structural complexity while enabling adaptation to varying seabed conditions. This dynamic feature allows the same basic structure to serve multiple height requirements without requiring completely different bushing designs

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feed-through slot with movable bushing creates a universal solution that can accommodate different seabed conditions with a single structure. The bushing can be positioned at various heights along the slot to adapt to different installation scenarios and seabed changes, eliminating the need for multiple fixed-design variants

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3696326B1Foundation of an offshore structure with submarine cable duct
Publication Date: 2021.11.17 RWE RENEWABLES GMBH
  • EP3696326B1 patent drawingFigure 1
  • EP3696326B1 patent drawingFigure 2A
  • EP3696326B1 patent drawingFigure 2B

AI summary

The invention relates to a foundation (1) of an offshore structure (B), in particular an offshore wind turbine, comprising at least one foundation pile (2), wherein the foundation pile (2) has a submarine cable penetration (4) for routing a submarine cable (K). To largely prevent damage to submarine cables in the area of ​​the submarine cable penetrations, the submarine cable penetration (4) has at least one penetration slot (5) provided in the foundation pile (2) and extending at least predominantly parallel to the longitudinal axis of the foundation pile (2), and the submarine cable penetration (4) is adjustable between at least one upper position for routing the submarine cable (K) through an upper section of the penetration slot (5) and at least one lower position for routing the submarine cable (K) through a lower section of the penetration slot (5).