Segmented Wind Turbine Blade Joint for Lightning Current Bypass
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Solution Overview
Problem
Segmented wind turbine blades with mechanical joints are vulnerable to lightning damage due to the metal elements of the joint acting as potential lightning attraction points, which can cause damage to the bolted joints and affect the mechanical properties.
Innovation Solution
A lightning protection system that redirects lightning current through the metallic joint instead of the bolts, using lightning down conductors connected to the joint's flanges, ensuring the current flows through the joint with lower electrical resistance and impedance, thus avoiding damage to the bolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical joints with bolts are used to assemble blade sections, then the blade can be manufactured in segments for easier transport and assembly, but the metal elements of the joint become lightning attraction points that can damage the bolted joint
Solution Approach 1:
The patent introduces a metallic joint as an intermediary component between blade sections. This joint serves dual functions: mechanically connecting the blade sections and providing a dedicated pathway for lightning current. The metallic joint acts as a mediator that diverts lightning current away from the bolts, preventing damage to the fastening elements while maintaining the segmented blade structure.
Solution Approach 2:
The blade is divided into multiple segments connected by metallic joints. Each joint is designed with specific electrical conductivity properties to guide lightning current. The segmentation allows the blade to be manufactured in manageable sections for transport, while the metallic joints provide continuous electrical pathways for lightning protection across the segmented structure.
2Reliability
If lightning down conductors are connected through fixtures between blade sections, then lightning current can be directed through the blade, but the fixture and metallic fairings add structural complexity and cost
Solution Approach 1:
The metallic joint is designed to perform multiple functions simultaneously: mechanical connection of blade sections, structural support, and lightning current conduction. By making the joint universal, the patent eliminates the need for separate fixtures and fairings, reducing structural complexity while maintaining reliable lightning protection.
Solution Approach 2:
The patent merges the lightning protection function into the existing metallic joint structure. Instead of adding separate fixtures and fairings, the joint itself is designed to conduct lightning current, combining multiple functions into a single integrated component and simplifying the overall structure.
3Object-affected harmful factors
If metallic fairings are used to shield the metallic joint, then the bolts are protected from lightning current, but the fairings and fixtures increase the device complexity
Solution Approach 1:
The patent extracts the lightning protection function from the separate fairing and fixture components and integrates it directly into the metallic joint. By taking out the protection function and placing it in the joint itself, the design eliminates the need for additional shielding components, reducing complexity while maintaining bolt protection.
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
The system effectively protects the bolts and mechanical joints from lightning damage by distributing the current through the metallic joint, maintaining the structural integrity and mechanical properties of the joint.
Implementation Method 1
a lightning down conductor that descends through the interior of the blade to a system that is located in the hub or blade root of the wind turbine, which guides the lightning current to the base of the wind turbine
Data Source
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AI summary
A lightning protection system for segmented wind turbine blades avoiding the lightning current to flow through the bolts (13,23) of the metallic joint (30) connecting the sections (10,20) of the blade is provided.