Ground-Based Lidar Wind Yaw Misalignment Detection
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Solution Overview
Problem
Existing methods for determining wind yaw misalignment in horizontal axis on-shore wind turbines are prone to errors due to the location of anemometers and wind vanes, which are affected by blade movement and turbulence, and while lidar systems provide improvements, they still suffer from systematic and random errors.
Innovation Solution
A system comprising a ground-based lidar and topographic station, with target points on the nacelle, determines wind direction and speed, and calculates wind yaw misalignment by averaging data from these sources to improve accuracy, using a computing unit to adjust and validate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If anemometer and wind vane are used to determine wind direction and speed, then the system can measure wind parameters, but the measurements are affected by blade movement and turbulence causing errors in yaw misalignment determination
Solution Approach 1:
The patent extracts the measurement function from the turbine-mounted anemometer and wind vane (which are affected by blade movement and turbulence) and replaces it with a ground-based lidar system. The lidar is positioned on the ground away from the turbine, eliminating the harmful interference from blade movement and turbulence while maintaining the ability to measure wind direction and speed accurately.
Solution Approach 2:
The patent introduces a ground-based lidar as an intermediary measurement device. Instead of measuring wind parameters directly at the turbine where interference occurs, the lidar acts as an intermediary by measuring wind parameters from a remote ground location, then transmitting this data to the control system for yaw alignment calculations.
2Measurement precision
If nacelle-mounted lidar is used to improve yaw alignment, then measurement accuracy improves, but systematic and random errors still affect the determination
Solution Approach 1:
The patent extracts the lidar system from the nacelle mounting position and relocates it to the ground. This removal from the nacelle eliminates systematic errors associated with nacelle movement, vibration, and positioning variability, while maintaining the lidar's ability to measure wind parameters accurately from a stable ground position.
3Reliability
If multiple measurement sources are averaged to improve accuracy, then measurement reliability improves, but system complexity increases
Solution Approach 1:
The patent merges multiple measurement functions (wind direction, wind speed, and nacelle orientation) into a single integrated system. The ground-based lidar provides both wind direction and speed measurements, while the topographic station provides nacelle orientation data. These merged measurements are processed together by the computing unit to calculate yaw misalignment, improving reliability while managing complexity through integration.
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 approach enhances the accuracy of wind yaw misalignment determination, leading to improved nacelle alignment with the wind, thereby increasing energy production efficiency.
Implementation Method 1
A system comprising a ground-based lidar and topographic station, with target points on the nacelle, determines wind direction and speed
Data Source
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AI summary
This invention relates to system for determining the wind yaw misalignment of a horizontal axis on-shore wind turbine comprising the wind turbine, a lidar, a topographical station, an external computing unit and a telecommunication network connecting them. Said wind turbine further comprises two target points made of reflective materials placed on the external surface of the nacelle on its side facing the ground, such that be detected by the topographic station. The lidar is configured to determine wind direction angle in respect to the north and wind speed, the topographic station is configured to determine the geographical position and orientation of the pair of target points. The lidar and the topographical station communicate the values determined to the external computing unit. The invention further relates to a method for determining the wind yaw misalignment of a horizontal axis on-shore wind turbine using the system of the invention. In the first step the wind direction angle in respect to the north, the wind speed and the geographical position and orientation of the pair of target points are determined and sent to the external computing unit. Then, in the second step, the external computing unit receives the values determined. In the third step, the external computing unit determines the angle of the geographical orientation of the nacelle in respect to the Geographical North. In the fourth step, the external computing unit applies a validation condition and a first compass rose condition and determines based on them an adjusted angle of the wind. Then, in the fourth step, the external computing unit averages the instant values of the adjusted angle of the wind direction and of the wind speed resulting the averaged angle of the wind direction and the averaged wind speed. Steps 6 and 7 of the method are carried only as long as the averaged wind speed vis comprised within the predetermined interval of wind speeds v1 - v2. In step 6 of the method, the external computing unit determines the wind yaw misalignment σ of the turbine T in respect to the wind direction as a difference between the averaged angle of the wind direction and the angle of the orientation of the nacelle. In the last step of the method, at the expiry of the duration of the method, the external computing unit determines the averaged wind yaw misalignment of the turbine as an arithmetic mean of the plurality of values of the wind yaw misalignment during the duration of the method. The invention further comprises a computer program for the external computing unit for carrying out the steps of the method as well as an external computing unit for carrying out the steps of the method.