As the demand for wind energy continues to grow at exponential rates, reducing operation and maintenance (OM) costs and improving reliability have become top priorities in wind turbine (WT) maintenance strategies. In addition to the development of more highly evolved WT designs intended to improve availability, the application of reliable and cost-effective condition-monitoring (CM) techniques offers an efficient approach to achieve this goal. This paper provides a general review and classification of wind turbine condition monitoring (WTCM) methods and techniques with a focus on trends and future challenges. After highlighting the relevant CM, diagnosis, and maintenance analysis, this work outlines the relationship between these concepts and related theories, and examines new trends and future challenges in the WTCM industry. Interesting insights from this research are used to point out strengths and weaknesses in today’s WTCM industry and define research priorities needed for the industry to meet the challenges in wind industry technological evolution and market growth.

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Wind Turbine Condition Monitoring: State-of-the-Art Review, New Trends, and Future Challenges

Gearbox fault diagnosis based on deep random forest fusion of acoustic and vibratory signals

Wind turbines have been developed fast in the recent years and at the same time have brought some problems. It is important to maintain the healthy condition of the running turbine because the consequences after faults are miserable for both the company and owner. There is a constant need to reduce the costs of operating and maintaining the turbines. Therefore, it is very important to detect the faults/failures early so as to minimize downtime and maximize productivity. This paper reviewed the structure of wind turbines and analyzed the different components of wind turbines in order to detect the faults that may happen. Meanwhile, this paper mainly reviewed fault diagnosis methods of wind turbines in the last three years. The main purpose of this paper is to supply some information on structure healthy condition monitoring (SHCM) and fault diagnosis in wind turbines for related researchers.

The structure healthy condition monitoring and fault diagnosis methods in wind turbines: A review

Wind energy is one of the fastest growing renewable energy resources. It is distinctly important to increase reliability and availability of wind turbines and further to reduce the wind energy cost. Blades are considered to be one of the most critical components in wind turbine system because they convert Kinetic energy of wind into useable power. Blades are fabricated by carbon fiber reinforced polymer (CFRP) or glass fiber reinforced polymer (GFRP). Flaws and damages are inevitable during either fabrication or lifetime of a composite blade. Thus, non-destructive testing (NDT) and structural health monitoring (SHM) for wind turbine blade (WTB) are required to prevent failures and increase reliability in both manufacturing quality control and in-service inspection. In this work, a fully, in-depth and comprehensive review of NDT techniques for WTB inspection was reported based on an orderly and concise literature survey. Firstly, typical flaw and damage occurring in manufacturing progress and in service of WTB were introduced. Next, the developments of visual, sonic and ultrasonic, optical, electromagnetic, thermal and radiographic NDT for composite WTB inspection were reviewed. Thereafter, strengths and limitations of NDT techniques were concluded through comparison studies. In the end, some research trends in WTB NDT have been predicted, for example in combination with SHM. This work will provide a guide for NDT and SHM of WTB, which plays an important role in wind turbine safety control and wind energy cost savings. In addition, this work can benefit the NDT development in the field of renewable energy, such as solar energy, and energy conservation field, such as building diagnosis.

Progress and trends in nondestructive testing and evaluation for wind turbine composite blade

Review of condition monitoring and fault diagnosis technologies for wind turbine gearbox

https://bura.brunel.ac.uk/bitstream/2438/8394/2/Fulltext.pdf

Determination of the combined vibrational and acoustic emission signature of a wind turbine gearbox and generator shaft in service as a pre-requisite for effective condition monitoring

The experimental results obtained from an online monitoring study of out-of-round defects in the slip-rings of wind turbine generators are presented. Five defects were involved, in which the slip-ring diameter varied from the normal value of 224 mm over large ranges of polar angle. The angular dependence of the radius changes was different for each defect and the amplitudes of the changes varied from 0.035 mm to 0.110 mm over the five defects. The defect detection sensor was a shock accelerometer embedded in the brush contacting the slip-ring and connecting the rotating and static parts of the generator. The time dependences of the brush acceleration produced by each defect, and also by a perfect slip-ring, were measured over continuous time intervals of 10 s for 11 slip-ring rotation speeds varying from 370 to 3827 rlmin. This covers the practical range of wind speed conditions. Fast Fourier transforms (FFTs) of this data were performed in order to present the acceleration data in the frequency domain, especially because such presentations promise rapid identification of sharp changes in the defect profiles with angle. Plots of the Fourier coefficients (acceleration amplitudes) as a function of the ring rotation speed are presented for the first four harmonics. These curves contain one or two maxima or show evidence of an approach to a maximum at higher revolution speeds. A qualitative explanation of these maxima is proposed and an outline is also presented of a quantitative model of the measured acceleration data, which is to be the subject of further work. In the first analysis of data, a strong and systematic dependence of these maximum acceleration amplitudes on the defect amplitudes was found. This result holds promise that the embedded accelerometer can form a suitable basis for an online alarm system in which an automatic warning is issued when the acceleration amplitude for any harmonic exceeds a level previously decided upon and set by the turbine operators. Further analysis of the data combined with modelling is in progress in order to investigate the possibility of obtaining the detailed profile of out-of-round defects in slip-rings from online time-dependent brush acceleration measurements.

Online monitoring of a power slip-ring on the shaft of a wind power generator

The use of a shock accelerometer for the continuous in-service monitoring of wear of the slip ring on a wind turbine generator is proposed and supporting results are presented. Five wear defects in the form of out-of-round circumference acceleration data with average radial dimensions in the range 5.9?25 ?m were studied. A theoretical model of the acceleration at a point on the circumference of a ring as a function of the defect profile is presented. Acceleration data as a continuous function of time have been obtained for ring rotation frequencies that span the range of frequencies arising with the variation of wind speeds experienced under all in-service conditions. As a result, the measured RMS acceleration is proven to follow an overall increasing trend with frequency for all defects at all brush pressures. A statistical analysis of the root mean square of the time acceleration data as a function of the defect profiles, rotation speeds and brush contact pressure has been performed. The detection performance is considered in terms of the achievement of a signal to noise ratio exceeding 3 (99.997% defect detection probability). Under all conditions of rotation speed and pressure, this performance was achieved for average defect sizes as small as 10 ?m, which is only 0.004% of the ring diameter. These results form the basis of a very sensitive defect alarm system.

Bryan Bridge

Papers

Determination of the combined vibrational and acoustic emission signature of a wind turbine gearbox and generator shaft in service as a pre-requisite for effective condition monitoring

Online monitoring of a power slip-ring on the shaft of a wind power generator

Statistical analysis of accelerometer data in the online monitoring of a power slip ring in a wind turbine