Cable-Stayed Tower Retrofitting Existing Wind Turbine Foundations

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Solution Overview

Problem

The existing process of replacing old wind turbines with newer, more efficient models is time-consuming and costly, requiring the transportation and re-deployment of large cranes and the installation of new foundations, which can take months and is inefficient, especially when trying to maintain power generation at prime wind sites.

Innovation Solution

The retrofitting of wind turbines involves using a cable-stayed tower design that reduces bending loads on the foundation and existing tower components, allowing for the reuse of the existing foundation and potentially parts of the tower, thereby extending their operational life and enabling the installation of a more powerful replacement wind turbine without the need for a new foundation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional replacement process is used to install a newer, more efficient wind turbine, then the energy generating capability is improved, but the replacement process becomes time-consuming and costly due to the need to install a new foundation

Engineering Contradiction:
Improveenergy generating capabilityVSAvoidreplacement process time
Core Design Contradiction:
PowerVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-installing the stay cables and cable anchorages on the existing foundation before the wind turbine is fully assembled. This allows the foundation to be prepared in advance, eliminating the need for time-consuming foundation installation during the turbine replacement process. The foundation is strengthened and ready to support the new turbine, reducing the overall replacement time from months to days.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the replacement process into distinct phases: foundation preparation with stay cable installation, turbine assembly, and connection. This segmentation allows the foundation work to be done independently and in parallel with turbine component preparation, rather than sequentially. The stay cable system is installed as a separate structural element that can be integrated with the existing foundation without requiring complete foundation replacement.

Inventive Principle:
Principle #1Segmentation

2Strength

If a new foundation is installed to support a larger replacement wind turbine, then the structural integrity is improved, but the cost and time for crane deployment and foundation installation increases

Engineering Contradiction:
Improvestructural integrityVSAvoidreplacement process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent introduces stay cables as an intermediary structural element that mediates between the existing foundation and the new wind turbine. These cables transfer and distribute the loads from the turbine to the foundation, allowing the existing foundation to support a larger turbine without requiring complete foundation replacement. This intermediary system simplifies the overall replacement process while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the structural parameters of the foundation system by adding stay cables that alter the load distribution and stress patterns. The cables modify how forces are transmitted from the turbine to the foundation, enabling the existing foundation to handle increased loads from a larger turbine. This parameter change allows reuse of the foundation while supporting enhanced turbine capacity.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If the existing foundation is reused to reduce replacement time and cost, then the loss of time is reduced, but the bending loads on the foundation may exceed its capacity

Engineering Contradiction:
Improvefoundation installation timeVSAvoidbending loads on foundation
Core Design Contradiction:
Loss of timeVSStress or pressure

Solution Approach 1:

The patent applies the anti-weight principle by using stay cables to counterbalance and distribute the bending loads on the existing foundation. The cables act as tension members that offset the moment forces generated by the turbine, reducing the net bending stress on the foundation. This allows the foundation to support a larger turbine without exceeding its original load capacity.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent introduces a new dimensional element to the foundation system by adding cable anchorages positioned at a distance from the tower. This creates a lever arm that reduces bending moments through moment redistribution. The stay cables extend in a different spatial dimension, creating a cable-stayed structure that fundamentally changes the load path and stress distribution throughout the foundation system.

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

Data Source

PatentEP3749854B1Retrofitted wind turbine installation and a method of retrofitting a wind turbine installation with a replacement wind turbine
Publication Date: 2024.04.10 VESTAS WIND SYSTEMS AS
  • EP3749854B1 patent drawingFigure 1
  • EP3749854B1 patent drawingFigure 2
  • EP3749854B1 patent drawingFigure 3

AI summary

A retrofitted wind turbine installation for replacing a prior wind turbine installation includes the foundation of the prior wind turbine installation and a replacement wind turbine supported by the foundation, wherein the tower of the retrofitted wind turbine installation is a cable-stayed tower to reduce the bending loads imposed on the foundation. A method of retrofitting an existing wind turbine installation with a replacement wind turbine includes disassembling at least a portion of the existing wind turbine, assembling a replacement tower to a remaining portion of the existing wind turbine installation, attaching a plurality of stay cables between the tower of the retrofitted wind turbine installation and stay cable foundations, and attaching the replacement energy generating unit to the replacement tower.