Wind Turbine Load Sensor Calibration During Rotor Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for calibrating load sensors on wind turbines are inadequate, as they often fail to provide accurate data for sophisticated load models, leading to potential inaccuracies in wear and damage mitigation, and may require precise rotor positioning or neglect axial loads, which can result in incomplete testing and potential damage to turbine components.
Innovation Solution
A method involving rotating wind turbine blades from a first calibration position to a second while rotating the rotor, with fewer blades moved to reduce aerodynamic effects, allowing for consistent and safe rotation, and using multiple sensors to determine axial, flap moment, and edge moment components to calculate load estimates, enabling more sophisticated modeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all rotor blades are moved to calibration positions while the rotor is rotating, then comprehensive calibration data can be obtained, but the rotor may stall or excessive speed may damage turbine components
Solution Approach 1:
The calibration process is segmented by moving only one blade at a time through its full range of motion while the other blades remain stationary. This divides the calibration task into manageable portions that can be performed sequentially without causing rotor stalling or excessive speed variations that would compromise turbine safety.
Solution Approach 2:
Instead of moving all blades simultaneously (excessive action), the method applies partial action by moving only one blade at a time during calibration. This partial movement approach provides sufficient calibration data while maintaining rotor stability and avoiding the harmful effects of moving all blades at once.
2Manufacturing precision
If the rotor is stopped at a specific position for calibration, then precise positioning can be achieved, but it is practically challenging to stop the rotor at a specific position with exacting precision
Solution Approach 1:
The method transitions from a static calibration approach (stopping the rotor) to a dynamic approach (calibrating while the rotor rotates). By performing calibration during continuous rotation, the system eliminates the practical difficulties of precisely stopping and positioning the rotor, while still obtaining accurate calibration data through dynamic measurement.
3Device complexity
If less sophisticated models are used for load calculations, then the calibration process is simpler, but axial loads due to centrifugal effects and forces not along the measurement axis are neglected leading to inaccuracies
Solution Approach 1:
The patent introduces a sophisticated load calculation model that acts as an intermediary between the simple sensor measurements and the actual blade loads. This model compensates for neglected factors such as axial loads and forces not aligned with measurement axes, thereby improving load estimation accuracy without requiring changes to the physical calibration setup.
4Productivity
If measurements are only taken during normal running of the turbine, then the turbine operates continuously, but full testing of all possible loading situations cannot be performed
Solution Approach 1:
The calibration process is performed as a preliminary action during scheduled maintenance or idle periods, rather than interrupting normal operation. This allows comprehensive calibration data to be collected when the turbine is not generating power, after which the turbine can resume continuous operation with improved load measurement accuracy.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of calibrating load sensors of a wind turbine, and a wind turbine for such load sensor calibration, are disclosed. The wind turbine comprises a rotor, a plurality of rotor blades, and a plurality of load sensors associated with the rotor blades. While the rotor is rotating, at least one of the rotor blades is moved from a first calibration position to a second calibration position, and load values from the load sensors are measured. The number of rotor blades being moved is at least one fewer than the number of the plurality of rotor blades. The rotation of the rotor may be during idling of the wind turbine. The movement of the blade(s) may be to change the pitch angle of the blade(s). At least one of the rotor blades not being moved to a calibration position may also be moved, for example to control the rotational speed of the rotor.