Wind Turbine Rotor Blade Lightning Protection Discharge Device
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Solution Overview
Problem
Current lightning protection systems in wind turbines face challenges such as increased stress and surface defects due to direct lightning strikes, leading to high repair and maintenance costs, as they are not designed to handle electrical loads intended for the bearing and are exposed to weather, which affects their reliability.
Innovation Solution
A compact lightning protection system is designed with a discharge device attached to the inside of the rotor blade root, using a comb-shaped contact plate and copper mesh for efficient current dissipation to the rotor hub, avoiding stress on the rotor blade and bearing, and ensuring reliable operation independent of weather conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current lightning protection systems are used with cables and bearings, then lightning current can be conducted away from the rotor blade, but the bearing is subjected to electrical load not intended for such use and surface defects occur
Solution Approach 1:
The invention extracts the lightning protection function from the bearing and cable system and relocates it to a dedicated discharge device mounted on the rotor blade surface. The discharge device includes a contact plate with comb-shaped fingers that contact the rotor blade skin, providing a separate pathway for lightning current that does not involve the bearing or internal cables.
Solution Approach 2:
The discharge device acts as an intermediary element between the rotor blade and ground. It provides a dedicated interface for lightning current discharge through the contact plate and comb-shaped fingers, mediating the electrical load away from sensitive components like the bearing and cable system.
2Reliability
If externally mounted lightning protection systems are used, then lightning current can be diverted, but the system is exposed to direct weather conditions and can influence airflow around the rotor
Solution Approach 1:
The discharge device is nested within the existing rotor blade structure rather than being externally mounted. The contact plate is positioned on the rotor blade surface with comb-shaped fingers that conform to the blade skin, allowing the system to be integrated into the blade's aerodynamic envelope without significant airflow disruption.
Solution Approach 2:
The contact plate features comb-shaped fingers that can flex and conform to the rotor blade surface. This flexible design allows the lightning protection system to adapt to the blade's curvature and weather-induced deformations while maintaining electrical contact, reducing weather exposure effects.
3Reliability
If compact concealed discharge device is used inside rotor blade root, then the system is protected from weather and bearing stress is avoided, but the contact area for current reception must be sufficient
Solution Approach 1:
The contact plate is segmented into multiple comb-shaped fingers instead of a single solid plate. This segmentation increases the effective contact area with the rotor blade surface while maintaining a compact overall structure. The multiple fingers provide redundant contact points that ensure sufficient current reception area within the constrained space of the concealed discharge device.
Solution Approach 2:
The comb-shaped fingers extend in a dimension perpendicular to the rotor blade surface, creating a three-dimensional contact interface. This dimensional approach maximizes the contact area within the limited space of the concealed discharge device, allowing sufficient current reception without increasing the device's footprint.
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 diverts lightning currents through the rotor blade tip, adapter rib, and contact plate, reducing damage and maintenance costs by providing a reliable and concealed lightning protection mechanism that maintains the mechanical structure's intended load stress and prevents electrostatic charging.
Implementation Method 1
the copper mesh (520), the rotor hub (240), and the tower (250), to the grounding device (260)
Implementation Method 2
Electrical conductivity is achieved by using a cold-welded connection between the contact plates and the copper mesh
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Exemplary embodiments of the present invention relate to a lightning protection system for a wind turbine as a discharge device for an electric current from a rotor blade (210). As a result of a lightning strike, a copper mesh (220) running along the rotor blade (210) conducts the electric current from an edge-sensitive sensor to a discharge device. The current conducted to the rotor hub (240) by means of the discharge device is discharged by a grounding device (260).