Wind Turbine Blade Conductor Bonding for Flashover Prevention
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Solution Overview
Problem
The integration of additional electrical conductors in wind turbine blades is complex and difficult due to the need for electrical connections along the spanwise length, especially in inaccessible regions, leading to increased manufacturing effort and risk of voltage differences causing flashovers.
Innovation Solution
The further electrical conductor is connected 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 inaccessible regions, 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 is improved, but the manufacturing complexity and difficulty increases significantly
Solution Approach 1:
The blade is divided into two separate half-shells that are manufactured independently and then joined. Electrical connections are established within each half-shell during its respective manufacturing process, avoiding the need to access the interior of the complete blade. This segmentation allows electrical bonding to be performed when the blade structure is still open and accessible, significantly reducing manufacturing complexity while maintaining the required potential equalization across the entire blade span.
2Reliability
If electrical connections are applied at multiple spanwise positions, then the voltage equalization is improved, but the accessibility and ease of operation during manufacturing deteriorates
Solution Approach 1:
Electrical connections are established in advance during the manufacturing of each half-shell while the structure is still accessible. The connections are made before the two half-shells are joined together to form the complete blade. This preliminary action ensures that multiple electrical bonding positions can be achieved without requiring later access to the interior of the assembled blade, thereby maintaining ease of operation during the connection process.
3Length of moving object
If the blade length is increased to improve energy generation, then the spanwise voltage distribution control is improved, but the accessibility for applying electrical connections deteriorates
Solution Approach 1:
The long blade is segmented into two half-shells that can be manufactured separately with electrical connections established during their respective fabrication processes. This segmentation allows the full spanwise length to be utilized for energy generation while the electrical bonding operations are performed on the accessible surfaces of the individual half-shells before assembly, avoiding the need to access the interior of the complete long blade structure.
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 number of necessary electrical connections, particularly in long blades with differently shaped spar caps.
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
Implementation Method 2
apply electrical bonds between all participant conductors in a blade at multiple positions along the spanwise length of the blade... an equalization of the potentials of the different conductors is obtained
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Wind turbine blade comprising two electrically conductive spar caps (10, 11), two lightning down conductor arrangements (12, 13), and a further electrical conductor (16), wherein the spar caps (10, 11) and the lightning down conductor arrangements (12, 13) extend along a spanwise direction of the blade (2) at least between a root-side end portion (19) and a tip-side end portion (20) of the blade (2), wherein each of the spar caps (10, 11) is electrically connected to only one of the lightning down conductor arrangements (12, 13) within a section (21) of the blade (2) between the root-side end portion (19) and the tip-side end portion (20), wherein the further electrical conductor (16) is electrically connected within the section (21) to only one of the spar caps (10, 11) and/or to only one of the lightning down conductor arrangements (12, 13) at one or more connection positions (22).