Wind Turbine Lightning Current Transfer System Segmentation
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Solution Overview
Problem
Large wind turbines with pitch controllable blades pose a challenge for lightning current transfer systems, as the increased hub size causes the blade band to rotate outside the nacelle perimeter, leading to higher impedance and potential damage to sensitive components like bearings and generators.
Innovation Solution
The lightning current transfer system splits the integral connecting device into two separate contact devices, allowing for increased separation distance from sensitive parts and using multiple contact points on the nacelle side to distribute current, reducing wear and adding redundancy, while reusing existing parts for larger turbines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the hub size is increased to accommodate pitch controllable blades, then the blade band rotates outside the nacelle perimeter, but this leads to higher impedance and potential damage to sensitive components
Solution Approach 1:
The patent divides the single contact device into two separate contact devices: a first contact device on the hub side and a second contact device on the nacelle side. This segmentation allows the lightning current path to be separated into distinct segments, reducing the impedance of each segment and enabling independent optimization of each contact device's position and design.
Solution Approach 2:
The patent introduces a connecting device as an intermediary element that electrically connects the first contact device (on the hub) with the second contact device (on the nacelle). This intermediary allows the lightning current to transfer from the rotating blade band through the hub to the stationary nacelle without requiring a direct long-distance connection, thereby reducing overall impedance.
2Device complexity
If a single contact device is used to connect the blade band to the nacelle, then the structure is simple, but the current concentration causes high wear and reduced redundancy
Solution Approach 1:
The patent segments the single contact device into two separate contact devices positioned at different locations. The first contact device contacts the blade band at the hub, while the second contact device contacts the nacelle. This segmentation distributes the lightning current across multiple contact points, reducing current concentration and wear at any single point while adding redundancy to the system.
3Length of stationary object
If the contact device is positioned close to the blade band for compact design, then the structure is compact, but the impedance increases and sensitive components are at risk
Solution Approach 1:
By segmenting the contact system into two separate contact devices, the patent enables the first contact device to be positioned close to the blade band on the hub while the second contact device is positioned on the nacelle. The connecting device bridges these segments, allowing compact local positioning while maintaining low overall impedance through the distributed current path.
Solution Approach 2:
The patent transitions from a single-point contact approach to a distributed multi-point contact system across different spatial dimensions. The first contact device operates in the hub dimension while the second contact device operates in the nacelle dimension, with the connecting device providing the dimensional bridge. This dimensional distribution reduces impedance by spreading the current path across multiple spatial locations.
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 configuration reduces impedance and wear, enhances safety by distributing current over multiple points, and allows for in-situ maintenance, effectively protecting sensitive components from lightning strikes in larger wind turbines.
Implementation Method 1
The first contact device (70) is configured to form a sliding contact with the blade band (10A) so as to establish an electrical connection between the blade band and the lightning ring (80). The second contact device (30B) is configured to form a sliding contact with the lightning ring (80) so as to establish an electrical connection between the lightning ring and the nacelle (30).
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The present invention relates to a lightning current transfer system (100) adapted for usage in a wind turbine (W) having a hub (20) that is rotatably supported relative to a generator in a nacelle (30) and a plurality of blades (10) that are pivotably connected with the hub, wherein the hub (20) is covered by a spinner (20A). The lightning current transfer system (100) comprises a blade band (10A) mountable to the root of the blade (10); a lightning ring (80) mountable to the spinner (20A) facing the nacelle (30); a first contact device (70) mountable to the spinner (20A) adapted for providing lightning current transfer from the blade band (10A); a connecting device (75) for connecting the first contact device (70) with the lightning ring (80); and a second contact device (30B) mountable to the nacelle (30) and adapted for providing lightning current transfer from the lightning ring (80) to ground.