Wind Turbine Tower Oscillation Control via Dynamic Thresholds
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Solution Overview
Problem
Wind energy installations experience tower oscillations due to asymmetries, imbalances, and environmental conditions, leading to material stress and reduced service life, with existing methods relying on constant switch-off thresholds that are either too trigger-happy during strong winds or fail to detect damaging oscillations during light winds.
Innovation Solution
A method that defines tower oscillation limit values as a function of prevailing wind speed, with different functional dependencies in various wind speed ranges, allowing for continuous transitions and adjustments based on operational states and meteorological conditions, enabling more accurate detection and prevention of oscillation-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant switch-off thresholds are used for tower oscillations, then the installation is protected from excessive oscillation damage, but unnecessary shutdowns occur during strong winds and damaging oscillations are missed during light winds
Solution Approach 1:
The patent applies dynamics by transitioning from static constant threshold values to dynamic threshold values that continuously adapt to current operating conditions. The threshold is made a function of rotational speed, wind speed, and turbulence intensity, allowing it to change in real-time according to the actual operational state of the wind turbine
Solution Approach 2:
The patent implements parameter changes by modifying the threshold parameters based on multiple operational variables. The switch-off threshold is expressed as a function of rotational speed (ω), wind speed (v), and turbulence intensity (TI), with each parameter influencing the threshold to reflect actual oscillation risks under different operating conditions
2Productivity
If high limit values are set to avoid unnecessary shutdowns during strong winds, then availability improves, but the tower may be exposed to damaging oscillations during light winds
Solution Approach 1:
The patent applies local quality by creating different threshold characteristics for different operating conditions. Instead of a single uniform threshold, the system establishes locally optimized thresholds for various combinations of rotational speed, wind speed, and turbulence intensity, ensuring appropriate protection levels for each specific operating regime
Solution Approach 2:
The dynamic threshold function continuously adjusts the limit values based on real-time operational parameters, lowering thresholds when conditions are favorable for detecting damaging oscillations and raising them when operational conditions naturally produce higher oscillations without damage risk
3Reliability
If low limit values are used to detect damaging oscillations during light winds, then tower protection improves, but unnecessary shutdowns increase during strong winds
Solution Approach 1:
The patent uses parameter changes to adjust the detection sensitivity based on operating conditions. The threshold function incorporates rotational speed, wind speed, and turbulence intensity parameters that automatically modify the limit values to match the expected oscillation characteristics at each operating point
Solution Approach 2:
The system implements feedback by continuously monitoring operational parameters and using them to adjust the switch-off threshold in real-time. The threshold is not fixed but is continuously updated based on feedback from sensors measuring rotational speed, wind conditions, and tower oscillations
Data Source
AI summary
A method for operating a wind energy installation having a tower, a nacelle arranged on the tower, the azimuth of which can be adjusted, and a rotor having at least one rotor blade, the blade angle of which can be adjusted, in which tower oscillations are detected and monitored during operation using at least one measuring apparatus and power operation is switched off if a sliding average of the tower oscillations exceeds a tower oscillation limit value. The tower oscillation limit value is defined, at least during load operation of the wind energy installation, as at least one limit value function which is dependent on a sliding average of prevailing wind speed and/or a parameter associated therewith, and has different functional dependencies in a plurality of different value ranges of the prevailing wind speed or the parameter associated therewith. The invention also relates to a wind energy installation.