3D Blade Vibration Measurements on an 80 m Diameter Wind Turbine by Using Non-contact Remote Measurement Systems

A technique for measuring turbine engine rotor blade vibrations has been developed as an alternative to conventional strain-gage measurement systems. Light probes are mounted on the periphery of the engine rotor casing to sense the precise blade passing times of each blade in the row. The timing data are processed on-line to identify (1) individual blade vibration amplitudes and frequencies, (2) interblade phases, (3) system modal definitions, and (4) blade static deflection. This technique has been effectively applied to both turbine engine rotors and plant rotating machinery.

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Preliminary Results of Vibration Measurements on a Wind Turbine Test Bench

Topics in Modal Analysis & Testing, Volume 8 - Conference Proceedings of the Society for Experimental Mechanics Series ◽

10.1007/978-3-030-47717-2_21 ◽

2020 ◽

pp. 211-220

Author(s):

Jesper Berntsen ◽

Anders Brandt

Keyword(s):

Wind Turbine ◽

Test Bench ◽

Vibration Measurements ◽

Preliminary Results

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Modeling of a Wind Turbine Rotor Blade System

Journal of Vibration and Acoustics ◽

10.1115/1.4036633 ◽

2017 ◽

Vol 139 (5) ◽

Cited By ~ 6

Author(s):

Dayuan Ju ◽

Qiao Sun

Keyword(s):

Wind Turbine ◽

Rotor Blade ◽

Simulation Software ◽

Wind Flow ◽

Coupling Effects ◽

Horizontal Axis Wind Turbine ◽

Blade Vibration ◽

Proposed Model ◽

Blade System ◽

Coupling Terms

In wind turbine blade modeling, the coupling between rotor rotational motion and blade vibration has not been thoroughly investigated. The inclusion of the coupling terms in the wind turbine dynamics equations helps us understand the phenomenon of rotor oscillation due to blade vibration and possibly diagnose faults. In this study, a dynamics model of a rotor-blade system for a horizontal axis wind turbine (HAWT), which describes the coupling terms between the blade elastic movement and rotor gross rotation, is developed. The model is developed by using Lagrange's approach and the finite-element method has been adopted to discretize the blade. This model captures two-way interactions between aerodynamic wind flow and structural response. On the aerodynamic side, both steady and unsteady wind flow conditions are considered. On the structural side, blades are considered to deflect in both flap and edge directions while the rotor is treated as a rigid body. The proposed model is cross-validated against a model developed in the simulation software fatigue, aerodynamics, structure, and turbulence (fast). The coupling effects are excluded during the comparison since fast does not include these terms. Once verified, we added coupling terms to our model to investigate the effects of blade vibration on rotor movement, which has direct influence on the generator behavior. It is illustrated that the inclusion of coupling effects can increase the sensitivity of blade fault detection methods. The proposed model can be used to investigate the effects of different terms as well as analyze fluid–structure interaction.

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An Improved Circumferential Fourier Fit (CFF) Method for Blade Tip Timing Measurements

Applied Sciences ◽

10.3390/app10113675 ◽

2020 ◽

Vol 10 (11) ◽

pp. 3675

Author(s):

Zhibo Liu ◽

Fajie Duan ◽

Guangyue Niu ◽

Ling Ma ◽

Jiajia Jiang ◽

...

Keyword(s):

Development Program ◽

Time Of Arrival ◽

Blade Vibration ◽

Vibration Measurements ◽

Rotating Speed ◽

Resonance Analysis ◽

Rotating Blade ◽

Negative Effect ◽

Frequency Identification ◽

Blade Tip

Rotating blade vibration measurements are very important for any turbomachinery research and development program. The blade tip timing (BTT) technique uses the time of arrival (ToA) of the blade tip passing the casing mounted probes to give the blade vibration. As a non-contact technique, BTT is necessary for rotating blade vibration measurements. The higher accuracy of amplitude and vibration frequency identification has been pursued since the development of BTT. An improved circumferential Fourier fit (ICFF) method is proposed. In this method, the ToA is not only dependent on the rotating speed and monitoring position, but also on blade vibration. Compared with the traditional circumferential Fourier fit (TCFF) method, this improvement is more consistent with reality. A 12-blade assembly simulator and experimental data were used to evaluate the ICFF performance. The simulated results showed that the ICFF performance is comparable to TCFF in terms of EO identification, except the lower PSR or more number probes that have a more negative effect on ICFF. Besides, the accuracy of amplitude identification is higher for ICFF than TCFF on all test conditions. Meanwhile, the higher accuracy of the reconstruction of ICFF was further verified in all measurement resonance analysis.

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Diagnosis of Faulty Wind Turbine Bearings Using Tower Vibration Measurements

Energies ◽

10.3390/en13061474 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1474 ◽

Cited By ~ 4

Author(s):

Francesco Castellani ◽

Luigi Garibaldi ◽

Alessandro Paolo Daga ◽

Davide Astolfi ◽

Francesco Natili

Keyword(s):

Wind Turbine ◽

Condition Monitoring ◽

Wind Turbines ◽

Statistical Tests ◽

Novelty Detection ◽

General Idea ◽

Data Set ◽

Vibration Measurements ◽

Bearing Fault ◽

Operation Conditions

Condition monitoring of gear-based mechanical systems in non-stationary operation conditions is in general very challenging. This issue is particularly important for wind energy technology because most of the modern wind turbines are geared and gearbox damages account for at least the 20% of their unavailability time. In this work, a new method for the diagnosis of drive-train bearings damages is proposed: the general idea is that vibrations are measured at the tower instead of at the gearbox. This implies that measurements can be performed without impacting the wind turbine operation. The test case considered in this work is a wind farm owned by the Renvico company, featuring six wind turbines with 2 MW of rated power each. A measurement campaign has been conducted in winter 2019 and vibration measurements have been acquired at five wind turbines in the farm. The rationale for this choice is that, when the measurements have been acquired, three wind turbines were healthy, one wind turbine had recently recovered from a planetary bearing fault, and one wind turbine was undergoing a high speed shaft bearing fault. The healthy wind turbines are selected as references and the damaged and recovered are selected as targets: vibration measurements are processed through a multivariate Novelty Detection algorithm in the feature space, with the objective of distinguishing the target wind turbines with respect to the reference ones. The application of this algorithm is justified by univariate statistical tests on the selected time-domain features and by a visual inspection of the data set via Principal Component Analysis. Finally, a novelty index based on the Mahalanobis distance is used to detect the anomalous conditions at the damaged wind turbine. The main result of the study is that the statistical novelty of the damaged wind turbine data set arises clearly, and this supports that the proposed measurement and processing methods are promising for wind turbine condition monitoring.

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