Wind Turbine Blade State Detection Using Load Signal Frequencies
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Solution Overview
Problem
Modern wind turbines with larger rotor diameters face issues with flexible blades prone to dynamic perturbations and ice accretion, which affects aerodynamic efficiency, structural integrity, and poses safety risks due to uneven ice accumulation and detachment, necessitating effective detection methods.
Innovation Solution
A method for detecting blade state through analyzing load signals at different frequencies to identify shifts in energy content, allowing detection of ice accumulation without additional equipment, using existing sensors to monitor blade condition during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ice detection systems based on cameras are used, then ice presence can be detected, but additional equipment is installed and power output may be affected
Solution Approach 1:
The wind turbine blade serves itself by using its own structural response (vibrations and oscillations) as the detection mechanism. The blade's natural frequency changes when ice accumulates on it, allowing the blade to essentially detect its own ice-covered state without external detection equipment.
Solution Approach 2:
The patent replaces optical detection systems (cameras) with a mechanical sensing approach. Instead of using cameras to visually detect ice, the system uses mechanical sensors to detect changes in the blade's vibrational characteristics and structural response, which indirectly indicate ice accumulation.
2Reliability
If ice detection systems are installed, then blade state can be monitored, but the overall power output of the wind turbine is affected
Solution Approach 1:
The monitoring system uses the blade's own structural vibrations and load responses as the sensing mechanism, eliminating the need for separate detection equipment that would add complexity and potentially affect power output. The blade essentially monitors its own state through its inherent mechanical properties.
3Productivity
If the rotor size increases to capture more energy, then power output increases, but blade stiffness is not proportionally increased leading to more flexible blades
Solution Approach 1:
The patent exploits the change in the blade's natural frequency parameter as ice accumulates on it. By monitoring shifts in this frequency parameter through vibration analysis, the system can detect ice accumulation. The increased flexibility of larger blades is actually utilized as a sensing characteristic rather than being treated as a weakness.
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
Enables precise and non-invasive monitoring of blade state, facilitating timely maintenance and reducing operational risks by detecting ice accumulation without affecting power output.
Implementation Method 1
Said dynamic perturbations may lead to edgewise and spanwise oscillations
Implementation Method 2
receiving one or more load signals from one or more sensors configured to measure loads on the wind turbine blade
Implementation Method 3
determining an energy of the load signals at a first frequency, and determining an energy of the load signals at a second frequency
Data Source
AI summary
The present disclosure is related to methods (400; 500; 600) configured for detecting the state of a wind turbine blade (22). The methods (400; 500; 600) comprising receiving (401; 501) load signals from a wind turbine blade (22), determining (402; 503) an energy of the load signal in a first and second frequency and comparing (403; 504) said energy to generate a flag signal if the energy in the first frequency is smaller than the energy in the second frequency. A control system (600) suitable to detect the state of a wind turbine blade (22) is also provided, as well as wind turbines (10) including such a control system (600).