Wind Turbine Blade Lightning Protection via Heating Device

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Solution Overview

Problem

Wind turbine rotor blades face damage from lightning strikes due to induced high voltages and currents in electrical heating devices, which can lead to flashovers and damage when used in conjunction with lightning protection conductors.

Innovation Solution

The implementation of a wind turbine rotor blade design featuring exactly two lightning protection conductors, each electrically connected to an electrical heating device at multiple points between the rotor blade root and tip, allowing for potential equalization between the conductors and preventing damage from induced voltages and currents during a lightning strike.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lightning protection conductor is arranged in the rotor blade to conduct lightning current to ground, then lightning protection is improved, but high voltages are induced in the electrical heating device due to Maxwell's law of induction, causing potential differences and flashovers

Engineering Contradiction:
Improvelightning protectionVSAvoidinduced high voltages and flashovers
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the equipotentiality principle by electrically connecting the lightning protection conductor to the electrical heating device at multiple points along their length. This creates equipotential zones that equalize the potential between the conductor and heating device during lightning strikes, preventing dangerous potential differences and flashovers while maintaining effective lightning current conduction to ground

Inventive Principle:
Principle #12Equipotentiality

2Adaptability or versatility

If the electrical heating device is connected to power supply lines running parallel to the lightning protection conductor, then heating function is enabled, but the parallel arrangement increases vulnerability to induced voltages and flashovers during lightning strikes

Engineering Contradiction:
Improveheating functionVSAvoidlightning resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges the electrical heating device with the lightning protection conductor system by creating multiple electrical connections between them. This integration allows the heating device to serve dual purposes: providing anti-icing heating during normal operation and acting as part of the lightning protection system by equalizing potential during strikes, thereby improving reliability without sacrificing heating functionality

Inventive Principle:
Principle #5Merging (Combining)

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 design effectively prevents damage to the rotor blade by equalizing potential differences through the electrical heating device, ensuring the lightning protection conductors can divert high current intensities without causing harm, and allows for additional lightning receptors at a distance from the rotor blade tip to further mitigate damage risks.

Implementation Method 1

These consist of an electrically conductive material and a heating current flows through them during operation, which leads to heating of the heating device

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The current from lightning striking the lightning protection receptor is then conducted via the lightning protection conductor to the rotor blade root

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

In the event of a lightning strike, electrical currents with very large and rapidly increasing current intensities are discharged via the lightning protection conductor, which, due to Maxwell's law of flooding, creates a strongly changing magnetic field in the area surrounding the lightning protection conductor

Methodology Applied
Scientific EffectMaxwell's law of flooding: Electromagnetic Induction

Implementation Method 4

Due to Maxwell's law of induction, high voltages can subsequently be induced in the electrical heating device

Methodology Applied
Scientific EffectMaxwell's law of induction: Electromagnetic Induction

Data Source

PatentEP2806160B1Wind turbine rotor blade with an electric heating device and multiple lightning conductors
Publication Date: 2017.07.05 NORDEX ENERGY
  • EP2806160B1 patent drawingFigure 1
  • EP2806160B1 patent drawingFigure 2~3
  • EP2806160B1 patent drawingFigure 4~5

AI summary

Wind turbine rotor blade comprising a rotor blade root, a rotor blade tip, an electric heating device, a lightning receptor in the region of the rotor blade tip, and several lightning protection conductors leading from the lightning receptor to the rotor blade root, characterized in that ● exactly two lightning protection conductors are present, ● at least one further lightning receptor is present, which is arranged at a distance from the rotor blade tip and connected to one of the lightning protection conductors, and ● each of the two lightning protection conductors is electrically connected to the electric heating device at a plurality of points between the rotor blade root and the rotor blade tip, so that in the event of a lightning strike, equipotential bonding takes place between the two lightning protection conductors via the electric heating device.