Wind Turbine Blade Lightning Conductor Layout for Flashover Control
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Solution Overview
Problem
The integration of additional electrical conductors in wind turbine blades is complex due to limited access during manufacturing, leading to difficulties in establishing electrical connections, especially between spar caps and lightning down conductor arrangements, which can result in large voltage differences and potential flashovers.
Innovation Solution
The solution involves connecting a further electrical conductor to only one of the spar caps and/or lightning down conductor arrangements within a section of the blade, eliminating connections between these components in the intermediate section, thereby reducing the number of required electrical connections and facilitating manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical connections are applied between all participant conductors at multiple positions along the spanwise length of the blade, then the potential equalization and voltage reduction are improved, but the manufacturing complexity and difficulty of applying connections increase significantly
Solution Approach 1:
The blade is divided into different sections (first section with multiple connections, second section with reduced connections). This segmentation allows the patent to apply multiple electrical connections in the accessible root section for good potential equalization, while reducing connections in the tip section where manufacturing access is difficult, thus resolving the contradiction between reliability and manufacturing complexity
Solution Approach 2:
The patent applies different connection densities to different sections of the blade. The first section (root area) has multiple electrical connections for optimal potential equalization, while the second section (tip area) has reduced connections. This local differentiation optimizes the balance between achieving reliable potential equalization and managing manufacturing complexity in different regions
2Reliability
If electrical connections are applied at all spanwise positions including inaccessible areas, then the voltage differences between conductors are reduced, but the ease of manufacture deteriorates due to limited worker access
Solution Approach 1:
The spanwise length of the blade is segmented into a first section (root area with good worker access) and a second section (tip area with limited access). Electrical connections are applied at multiple positions in the first section where workers can easily access and apply connections, while in the second section connections are applied at reduced positions. This segmentation resolves the contradiction by matching the level of connection application to the manufacturability of each section
Solution Approach 2:
The patent applies partial action by not providing electrical connections at all possible positions along the entire blade span. Instead, connections are provided at multiple positions in the accessible root section and at reduced positions in the tip section. This partial application is sufficient to achieve the safety objective of preventing large voltage differences while significantly improving ease of manufacture compared to full coverage
3Reliability
If multiple electrical connections are made between spar caps and lightning down conductor arrangements, then the maximum voltage between conductors is reduced, but the number of required electrical bonds increases
Solution Approach 1:
The blade is segmented into two sections with different connection requirements. In the first section, multiple electrical bonds are made between spar caps and lightning down conductor arrangements to achieve good voltage equalization and reduce maximum voltage. In the second section, the number of electrical bonds is reduced. This segmentation allows the patent to achieve reliable voltage reduction where needed while reducing the total number of bonds required
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 approach maintains safe voltage differences, prevents flashovers, and simplifies the manufacturing process by reducing the complexity of electrical bonding, especially in long blades with varying spar cap geometries.
Implementation Method 1
electrical conductors or electrically conductive blade segments may be present in the blades to allow for the grounding of lightning strikes hitting the blade
Data Source
AI summary
A wind turbine blade including two electrically conductive spar caps, two lightning down conductor arrangements, and a further electrical conductor, wherein the spar caps and the lightning down conductor arrangements extend along a spanwise direction of the blade at least between a root-side end portion and a tip-side end portion of the blade, wherein each of the spar caps is electrically connected to only one of the lightning down conductor arrangements within a section of the blade between the root-side end portion and the tip-side end portion, wherein the further electrical conductor is electrically connected within the section to only one of the spar caps and/or to only one of the lightning down conductor arrangements at one or more connection positions is provided.