Wind Turbine Rotor Blade Discharge Roller Contact
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Solution Overview
Problem
Conventional sliding contact arrangements in wind turbine lightning conductor systems face challenges in maintaining a stable electrical contact, leading to intermittent current paths and potential high voltage sparking flashovers due to contact lift-off, which can cause damage.
Innovation Solution
The rotor-blade discharge unit employs a roller device with elastomeric or carbonaceous contact wheels that deform against a conductive slideway, creating a larger contact surface and reducing the risk of lift-off, along with a spark gap that provides a parallel current path to bypass lightning currents, preventing thermal damage to the contact wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sliding contact arrangements are used, then the device complexity is reduced, but the reliability of electrical contact deteriorates due to contact lift-off and intermittent current paths
Solution Approach 1:
The patent employs a roller device with a contact wheel that has a curved rolling surface instead of a flat sliding contact. This curvature allows the contact wheel to roll along the conductive slideway while maintaining continuous contact, eliminating the lift-off problems associated with conventional sliding contacts and ensuring stable electrical connection.
Solution Approach 2:
The patent replaces the conventional sliding mechanical contact system with a rolling contact system. The roller device converts sliding friction into rolling friction, providing more reliable electrical contact while reducing wear and maintaining continuous connectivity between the rotor blade and nacelle.
2Object-affected harmful factors
If sliding contacts are used to bridge the gap, then the device complexity remains low, but harmful factors increase due to high voltage sparking flashovers from contact instability
Solution Approach 1:
The curved rolling surface of the contact wheel ensures continuous and stable contact with the conductive slideway, preventing the intermittent contact that leads to high voltage sparking and flashovers. The rolling motion maintains constant electrical connectivity, eliminating the harmful sparking effects.
3Reliability
If the contact surface area is increased to improve stability, then the reliability improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The contact wheel with its curved rolling surface naturally provides an extended contact area with the conductive slideway during rolling motion. This geometric solution achieves improved contact stability without requiring complex manufacturing processes, as the curved surface can be formed through standard wheel fabrication techniques.
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 solution ensures a stable and efficient discharge of static and lightning charges from rotor blades to the nacelle, reducing the risk of thermal damage and maintaining continuous electrical contact, even in cold climates, while minimizing noise and wear.
Implementation Method 1
the rolling surface is arranged to deform against the conductive slideway under the bias acting on the roller device. Thereby a contact surface between the wheel and the conductive slideway is formed
Implementation Method 2
A second current path is formed by a spark gap if a spark bridges that spark gap. This second current path is connected in parallel to the first current path
Data Source
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AI summary
A rotor-blade discharge unit enabling electric charges to be discharged from a rotor blade of a wind turbine, the rotor blade discharge unit comprising at least one current transfer arrangement, the current transfer arrangement comprising: a roller device, an electrically conductive slideway, and a spark gap, wherein the roller device is biased towards the conductive slideway and is movable relative to the conductive slideway, the roller device comprising: at least one contact wheel, having a rolling surface and the contact wheel is arranged to roll on the conductive slideway and is biased towards the conductive slideway, wherein the rolling surface is arranged to deform against the conductive slideway under the bias acting on the roller device, wherein the contact wheel and the conductive slideway form a first current path to discharge the electric charges and wherein the spark gap forms a second current path upon occurrence of a spark bridging the spark gap, wherein the second current path is connected in parallel to said first current path.