Wind Turbine Fatigue Monitoring via Power Spectral Density

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Solution Overview

Problem

Existing methods for monitoring fatigue damage in wind turbine components, such as rainflow cycle counting, are complex and require significant computing power, making real-time implementation costly and impractical, while current control strategies do not account for varying wind conditions leading to early decommissioning.

Innovation Solution

A method involving sensors to measure loads, calculate real power spectral density, and compare it to reference spectral densities to determine accumulated fatigue damage in the frequency domain, allowing for real-time operational adjustments to extend the lifespan of wind turbine components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rainflow cycle counting method is used to determine fatigue damage, then measurement precision of fatigue damage is improved, but device complexity and computing power requirements increase significantly

Engineering Contradiction:
Improvefatigue damage measurement precisionVSAvoidcomputing power requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the time-domain rainflow cycle counting method with a frequency-domain approach using power spectral density (PSD) analysis. This substitution transforms the computational methodology from tracking individual load cycles to analyzing the spectral characteristics of load signals, significantly reducing computing power requirements while maintaining fatigue damage assessment capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter domain from time-domain load cycles to frequency-domain power spectral density. By transforming the analysis from temporal cycle counting to spectral analysis, the method achieves comparable measurement precision with substantially lower computational complexity, enabling real-time implementation in wind turbine control systems

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional control strategies are used, then ease of operation is maintained, but reliability of wind turbine components decreases due to unmonitored fatigue damage

Engineering Contradiction:
Improvecontrol strategy simplicityVSAvoidcomponent lifespan
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where real-time power spectral density analysis of load signals provides continuous information about accumulated fatigue damage. This feedback enables the control system to adjust operational parameters dynamically, extending component lifespan while maintaining operational simplicity through automated monitoring and adaptive control

Inventive Principle:
Principle #23Feedback

3Reliability

If real-time fatigue monitoring is implemented, then reliability of components is improved, but device complexity increases

Engineering Contradiction:
Improvecomponent lifespanVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex time-domain fatigue analysis with frequency-domain power spectral density analysis. This methodological substitution enables real-time fatigue monitoring with reduced computational complexity, as PSD analysis can be efficiently performed using standard signal processing techniques without requiring sophisticated rainflow cycle counting algorithms

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent makes the frequency-domain analysis method universally applicable to various wind turbine components and operating conditions. By using power spectral density as a general approach rather than component-specific methods, the system achieves broad reliability improvement across different turbine configurations while maintaining a standardized, relatively simple monitoring framework

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2927486B8Fatigue in wind turbines
Publication Date: 2019.07.24 GE RENEWABLE TECH WIND BV

AI summary

Methods of operating a wind turbine having one or more sensors for determining loads in selected wind turbine components, the methods comprising determining loads in the selected wind turbine components during a measuring period under a first wind condition, calculating a real power spectral density of one or more selected loads for each of the selected wind turbine components during the measuring period, obtaining a reference power spectral density for the selected loads for each of the selected wind turbine components under a wind condition that is comparable to the first wind condition, determining accumulated fatigue damage in time equivalent loads for each of the selected wind turbine components, verifying for each of the selected wind turbine components whether the accumulated fatigue damage in time equivalent loads is within acceptable limits, and performing one or more operational changes in case of negative result. Wind turbines suitable for these methods are also disclosed.