Video-Tachometer Methodology for Wind Turbine Rotor Speed Measurement

Area of Science:

• Mechanical Engineering
• Optical Measurement
• Condition Monitoring

Background:

• Traditional rotational speed measurement relies on mechanical encoders.
• Contactless methods offer advantages for monitoring rotating machinery, especially wind turbines.
• Non-intrusive condition monitoring is crucial for wind turbine technology.

Purpose of the Study:

• To propose a ground-level video-tachometer technique for contactless wind turbine rotor speed estimation.
• To develop an image analysis algorithm for accurate speed measurement.
• To demonstrate the method's robustness in diverse experimental settings.

Main Methods:

• A video-tachometer measurement technique is employed.
• Image analysis involves comparing video frames using a covariance matrix.
• Rotational speed is estimated from the covariance time series via spectrogram analysis.

Main Results:

• The proposed method reliably estimates rotational speed from video data.
• The technique proved effective for a small wind turbine model (0.45 m diameter) at high speeds (1500 RPM).
• The method also succeeded with a large-scale wind turbine (44 m diameter) under uncontrolled industrial conditions.

Conclusions:

• The developed video-tachometer method provides robust and reliable contactless estimation of wind turbine rotor speed.
• This technique is suitable for non-intrusive condition monitoring applications.
• The algorithm overcomes challenges posed by system non-stationarity and signal disturbances.