Wind Turbine Blade Lightning Protection Segmentation

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Solution Overview

Problem

Existing lightning protection systems for wind turbine blades face challenges such as structural damage from lightning penetration, high maintenance costs, and aerodynamic noise constraints, particularly in the case of wind turbine blade add-ons, which are vulnerable to lightning strikes and require complex and costly installation methods.

Innovation Solution

A lightning protection system for wind turbine blades is proposed, dividing the blade length into two parts: one with an internal down conductor and the other with an external conductive strip that electrically couples air termination devices, eliminating the need for an internal down conductor in the exposed tip region to prevent lightning penetration and reduce structural damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an internal down conductor is installed inside the wind turbine blade to protect against lightning strikes, then lightning protection is improved, but the risk of lightning penetration into the laminate increases causing structural damage

Engineering Contradiction:
Improvelightning protectionVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The blade is divided into two distinct zones: a first zone (from root to air termination device) with an internal down conductor for protection, and a second zone (from air termination device to tip) without internal conductor to prevent penetration. This segmentation allows the system to provide protection where needed while avoiding structural damage in the tip region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The internal down conductor is extracted from the tip region of the blade. By removing the conductor from the second zone (tip area), the patent eliminates the risk of lightning penetration into the laminate in that critical region, while maintaining protection in the first zone through the air termination device and external conductive strip.

Inventive Principle:
Principle #2Taking out (Extraction)

2Shape

If external down conductors are installed on the blade surface to preserve aerodynamic properties, then aerodynamic performance is improved, but maintenance costs and device complexity increase

Engineering Contradiction:
Improveaerodynamic propertiesVSAvoidmaintenance costs
Core Design Contradiction:
ShapeVSEase of repair

Solution Approach 1:

The patent uses a simple external conductive strip that can be easily installed and replaced if needed, rather than complex internal conductor systems. This straightforward external approach reduces maintenance complexity and costs while preserving aerodynamic properties.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If wind turbine blade add-ons are added to increase effective blade length, then energy capture is improved, but vulnerability to lightning strikes increases

Engineering Contradiction:
Improveenergy captureVSAvoidlightning strike vulnerability
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The add-on structure is segmented into a first zone (from blade root to air termination device) with internal conductor protection and a second zone (from air termination device to add-on tip) without internal conductor. This segmentation provides lightning protection in the first zone while avoiding penetration risks in the add-on tip region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An external conductive strip acts as an intermediary element connecting the air termination device to the add-on tip, providing a safe lightning conduction path without requiring internal conductors in the add-on structure, thus preventing penetration while maintaining protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If insulation is added to protect against lightning penetration, then structural damage is reduced, but weight of the blade increases

Engineering Contradiction:
Improveprotection from penetrationVSAvoidblade weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent eliminates the need for insulation by removing the internal down conductor from the tip region. Without the conductor present in the second zone, there is no risk of lightning penetration, thereby eliminating the need for additional insulation material and avoiding weight increase.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution provides enhanced protection against lightning strikes, reduces maintenance costs, and simplifies installation and inspection, while minimizing weight and aerodynamic impact, allowing for longer blade lifetimes and reduced manufacturing complexities.

Implementation Method 1

at least one second air termination device in the second part, and at least one external, electrically conductive strip extending at least between a pair of a first and a second air termination device in the second part and being electrically conductively coupled to their receptors

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3879091B1Wind turbine blade assembly and method for manufacturing a wind turbine blade assembly
Publication Date: 2024.03.27 SIEMENS GAMESA RENEWABLE ENERGY AS
  • EP3879091B1 patent drawingFigure 1~3
  • EP3879091B1 patent drawingFigure 4~6
  • EP3879091B1 patent drawingFigure 7~9

AI summary

Wind turbine blade assembly (1a, 1b, 1c, 1d), comprising - a wind turbine blade (2) having a blade root (7) for connection to the hub of a wind turbine, - an assembly tip (10), wherein the wind turbine blade assembly (1a, 1b, 1c, 1d) spans a length (11) from the blade root (7) to the assembly tip (10), and - a lightning protection system comprising an internal down conductor (3) inside the wind turbine blade (2) and multiple air termination devices (4, 6, 14) having a receptor (15), which is electrically conductively coupled to the down conductor (3), wherein the length (11) of the wind turbine blade assembly (1a, 1b, 1c, 1d) is divided into a first part (12) having the internal down conductor (3) and spanning from the blade root (7) to at least one first air termination device (4) and a second part (13) spanning from the first air termination device (4) to the assembly tip (10), wherein the lightning protection system further comprises - a second air termination device (6) in the second part (13), and - an external, electrically conductive strip (5) extending between a pair of a first and a second air termination devices (4, 6) in the second part (13) and being electrically conductively coupled to their receptors (15).