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26 pages, 10555 KiB

Open AccessArticle

Machine Learning on Fault Diagnosis in Wind Turbines

by Eddie Yin-Kwee Ng and Jian Tiong Lim

Fluids 2022, 7(12), 371; https://doi.org/10.3390/fluids7120371 - 02 Dec 2022

Cited by 8 | Viewed by 2286

With the improvement in wind turbine (WT) operation and maintenance (O&M) technologies and the rise of O&M cost, fault diagnostics in WTs based on a supervisory control and data acquisition (SCADA) system has become among the cheapest and easiest methods to detect faults [...] Read more.

With the improvement in wind turbine (WT) operation and maintenance (O&M) technologies and the rise of O&M cost, fault diagnostics in WTs based on a supervisory control and data acquisition (SCADA) system has become among the cheapest and easiest methods to detect faults in WTs.Hence, it is necessary to monitor the change in real-time parameters from the WT and maintenance action could be taken in advance before any major failures. Therefore, SCADA-driven fault diagnosis in WT based on machine learning algorithms has been proposed in this study by comparing the performance of three different machine learning algorithms, namely k-nearest neighbors (kNN) with a bagging regressor, extreme gradient boosting (XGBoost) and an artificial neural network (ANN) on condition monitoring of gearbox oil sump temperature. Further, this study also compared the performance of two different feature selection methods, namely the Pearson correlation coefficient (PCC) and principal component analysis (PCA), and three hyperparameter optimization methods on optimizing the performance of the models, namely a grid search, a random search and Bayesian optimization. A total of 3 years of SCADA data on WTs located in France have been used to verify the selected method. The results showed the kNN with a bagging regressor, with PCA and a grid search, provides the best R² score, and the lowest root mean square error (RMSE). The trained model can detect the potential of WT faults at least 4 weeks in advance. However, the proposed kNN model in this study can be trained with the Support Vector Machine hybrid algorithm to improve its performance and reduce fault alarm. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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20 pages, 7435 KiB

Open AccessArticle

Wind Turbine Blade Design Optimization for Reduced LCoE, Focusing on Design-Driving Loads Due to Storm Conditions

by Giannis Serafeim, Dimitris Manolas, Vasilis Riziotis and Panagiotis Chaviaropoulos

Fluids 2022, 7(8), 280; https://doi.org/10.3390/fluids7080280 - 16 Aug 2022

Viewed by 1601

Abstract

Design modifications of the blade inner structure, targeted at reducing design-driving extreme loads due to storm conditions, are assessed in the present paper. Under survival wind speeds, the lack of sufficient aerodynamic damping in the edgewise direction is responsible for excessive stall-induced vibrations [...] Read more.

Design modifications of the blade inner structure, targeted at reducing design-driving extreme loads due to storm conditions, are assessed in the present paper. Under survival wind speeds, the lack of sufficient aerodynamic damping in the edgewise direction is responsible for excessive stall-induced vibrations that usually drive wind turbine blade design loads. The modifications considered in the work are (i) a non-symmetric increase in the thickness of the uniaxial and tri-axial material on the suction and pressure side of the blade sections, (ii) a shift in the spar caps in opposite directions and (iii) the ply-angle re-orientation of the laminates on the spar caps. The first two design interventions aim at increasing the damping of the low-damped edgewise modes in the idling rotor, while the third aims at reducing the fatigue and ultimate loads in normal operation. The design parameters in the problem are determined on the basis of a multidisciplinary optimization (MDAO) process, which minimizes the levelized cost of energy (LCoE). The in-house integrated optimization tool employed in the present study combines: (i) a servo-aero-elastic analysis tool for calculating ultimate loads and power yield, (ii) a cross-sectional analysis tool for obtaining structural properties and stress distributions in the modified blades and (iii) a cost model of the overall wind turbine to evaluate the LCoE. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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19 pages, 3751 KiB

Open AccessArticle

CHP-Based Economic Emission Dispatch of Microgrid Using Harris Hawks Optimization

by Vimal Tiwari, Hari Mohan Dubey, Manjaree Pandit and Surender Reddy Salkuti

Fluids 2022, 7(7), 248; https://doi.org/10.3390/fluids7070248 - 18 Jul 2022

Cited by 7 | Viewed by 1498

Abstract

In this paper, the economically self-sufficient microgrid is planned to provide electric power and heat demand. The combined heat and power-based microgrid needs strategic placement of distributed generators concerning optimal size, location, and type. As fossil fuel cost and emission depend mainly on [...] Read more.

In this paper, the economically self-sufficient microgrid is planned to provide electric power and heat demand. The combined heat and power-based microgrid needs strategic placement of distributed generators concerning optimal size, location, and type. As fossil fuel cost and emission depend mainly on the types of distributed generator units used in the microgrid, economic emission dispatch is performed for an hour with a static load demand and multiple load demands over 24 h of a day. The TOPSIS ranking approach is used as a tool to obtain the best compromise solution. Harris Hawks Optimization (HHO) is used to solve the problem. For validation, the obtained results in terms of cost, emission, and heat are compared with the reported results by DE and PSO, which shows the superiority of HHO over them. The impact of renewable integration in terms of cost and emission is also investigated. With renewable energy integration, fuel cost is reduced by 18% and emission is reduced by 3.4% for analysis under static load demand, whereas for the multiple load demands over 24 h, fuel cost is reduced by 14.95% and emission is reduced by 5.58%. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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15 pages, 3522 KiB

Open AccessArticle

The Radiation Problem of a Submerged Oblate Spheroid in Finite Water Depth Using the Method of the Image Singularities System

by Eirini I. Anastasiou and Ioannis K. Chatjigeorgiou

Fluids 2022, 7(4), 133; https://doi.org/10.3390/fluids7040133 - 08 Apr 2022

Viewed by 1700

Abstract

This study examines the hydrodynamic parameters of a unique geometry that could be used effectively for wave energy extraction applications. In particular, we are concerned with the oblate spheroidal geometry that provides the advantage of a wider impact area on waves, closer to [...] Read more.

This study examines the hydrodynamic parameters of a unique geometry that could be used effectively for wave energy extraction applications. In particular, we are concerned with the oblate spheroidal geometry that provides the advantage of a wider impact area on waves, closer to the free surface where the hydrodynamic pressure is higher. In addition, the problem is formulated and solved analytically via a method that is robust and most importantly very fast. In particular, we develop an analytical formulation for the radiation problem of a fully submerged oblate spheroid in a liquid field of finite water depth. The axisymmetric configuration of the spheroid is considered, i.e., the axis of symmetry is perpendicular to the undisturbed free surface. In order to solve the problem, the method of the image singularities system is employed. This method allows for the expansion of the velocity potential in a series of oblate spheroidal harmonics and the derivation of analytical expressions for the hydrodynamic coefficients for the translational degrees of freedom of the body. Numerical simulations and validations are presented taking into account the slenderness ratio of the spheroid, the immersion below the free surface and the water depth. The validations ensure the correctness and the accuracy of the proposed method. Utilizing the same approach, the whole process is implemented for a disc as well, given that a disc is the limiting case of an oblate spheroid since its semi-minor axis approaches zero. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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27 pages, 1732 KiB

Open AccessArticle

Aeroelastic Response of Wind Turbine Rotors under Rapid Actuation of Flap-Based Flow Control Devices

by Muraleekrishnan Menon and Fernando Ponta

Fluids 2022, 7(4), 129; https://doi.org/10.3390/fluids7040129 - 06 Apr 2022

Cited by 1 | Viewed by 2282

Abstract

The largest commercial wind turbines today are rated at powers between 12 MW to 16 MW, with rotor diameters between 220 m to 242 m, which are expected to grow beyond 250 m in the near future. Economies-of-scale factors suggest the advantages of [...] Read more.

The largest commercial wind turbines today are rated at powers between 12 MW to 16 MW, with rotor diameters between 220 m to 242 m, which are expected to grow beyond 250 m in the near future. Economies-of-scale factors suggest the advantages of upscaling in rotor size to effectively harvest the wind potential. An increased emphasis on studies related to improvements and innovations in aerodynamic load-control methodologies has led researchers to focus on overcoming the bottlenecks in size upscaling. Though conventional pitch control is an effective approach for long-term load variations, their application to mitigate short-term fluctuations has limitations. This is directly associated with the cubical dependence on the weight of the rotor with increasing diameter. Alternatively, active flow-control devices (FCDs) have the potential to alleviate load fluctuations through rapid aerodynamic trimming. Fractional light-weight attachments such as trailing-edge flaps promise the swift response of such rapid fluctuations and require low power of actuation. The current study investigates the performance of active in dynamic load control for utility-scale wind turbines through an aeroelastic evaluation of the turbine response to control actions in short time-scales relevant to rapid load fluctuations. The numerical platform used in the analysis is designed to consider the complex multi-physics dynamics of the wind turbine through a self-adaptive Ordinary Differential Equation (ODE) algorithm that integrates the dynamics presented by control system in to the coupled response of aerodynamics and structural deformations of the rotor. The benchmark case in consideration is the use of fractional trailing-edge flaps used on blades designed for the NREL-5MW Reference Wind Turbine, originally designed by the National Renewable Energy Laboratory. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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15 pages, 16065 KiB

Open AccessArticle

A Modular Wave Energy Converter for Observational and Navigational Buoys

by Nicholas Vella, Jamie Foley, James Sloat, Alexander Sandoval, Leonardo D’Attile and Masoud Masoumi

Fluids 2022, 7(2), 88; https://doi.org/10.3390/fluids7020088 - 21 Feb 2022

Cited by 6 | Viewed by 3552

Abstract

More than 80% of the ocean is not fully mapped or even observed, even though it covers over 70% of our planet’s surface. One of the primary challenges for ocean observation and monitoring is the required power for exploration and monitoring systems, which [...] Read more.

More than 80% of the ocean is not fully mapped or even observed, even though it covers over 70% of our planet’s surface. One of the primary challenges for ocean observation and monitoring is the required power for exploration and monitoring systems, which often operate in remote areas of the ocean. This work addresses the design and development of an ocean wave energy converter that can be installed on observational buoys to provide enough power for sensors, cameras, data acquisition and recording, as well as data transfer units. The initial simulations of the prototype indicate that this system can produce up to 3.7–3.85 watts of power on average, with greater than 12 watts of maximum power in two selected sites in California and Hawaii. The proposed system is simple and low-cost. Further, multiple energy converters can be installed on one buoy to address higher power needs. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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25 pages, 6995 KiB

Open AccessArticle

Optimization of a Grid-Connected Microgrid Using Tidal and Wind Energy in Cook Strait

by Navid Majdi Nasab, Md Rabiul Islam, Kashem Muttaqi and Danny Sutanto

Fluids 2021, 6(12), 426; https://doi.org/10.3390/fluids6120426 - 25 Nov 2021

Cited by 9 | Viewed by 3141

Abstract

The Cook Strait in New Zealand is an ideal location for wind and tidal renewable sources of energy due to its strong winds and tidal currents. The integration of both technologies can help to avoid the detrimental effects of fossil fuels and to [...] Read more.

The Cook Strait in New Zealand is an ideal location for wind and tidal renewable sources of energy due to its strong winds and tidal currents. The integration of both technologies can help to avoid the detrimental effects of fossil fuels and to reduce the cost of electricity. Although tidal renewable sources have not been used for electricity generation in New Zealand, a recent investigation, using the MetOcean model, has identified Terawhiti in Cook Strait as a superior location for generating tidal power. This paper investigates three different configurations of wind, tidal, and wind plus tidal sources to evaluate tidal potential. Several simulations have been conducted to design a DC-linked microgrid for electricity generation in Cook Strait using HOMER Pro, RETScreen, and WRPLOT software. The results show that Terawhiti, in Cook Strait, is suitable for an offshore wind farm to supply electricity to the grid, considering the higher renewable fraction and the lower net present cost in comparison with those using only tidal turbines or using both wind and tidal turbines. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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17 pages, 4354 KiB

Open AccessArticle

CFD Simulation Study on the Performance of a Modified Ram Air Turbine (RAT) for Power Generation in Aircrafts

by Magedi Moh M. Saad, Sofian Mohd, Mohd Fadhli Zulkafli, Nor Afzanizam Samiran and Djamal Hissein Didane

Fluids 2021, 6(11), 391; https://doi.org/10.3390/fluids6110391 - 01 Nov 2021

Cited by 4 | Viewed by 3117

Abstract

The present paper aims to study the possibility of dispensing an auxiliary power unit (APU) in an aircraft powered by fossil fuels to reduce air pollution. It particularly seeks to evaluate the amount of power generated by the ram air turbine (RAT) using [...] Read more.

The present paper aims to study the possibility of dispensing an auxiliary power unit (APU) in an aircraft powered by fossil fuels to reduce air pollution. It particularly seeks to evaluate the amount of power generated by the ram air turbine (RAT) using the novel counter-rotating technique while characterizing its optimum axial distance. The ram air turbine (RAT), which is already equipped in aircrafts, was enhanced to generate the amount of energy produced by the APU. The approach was implemented by a CRRAT system. Six airfoil profiles were tested based on 2D models and the best airfoil was chosen for implantation on the RAT and CRRAT systems. The performance of the conventional single-rotor RAT and CRRAT were analyzed using FLUENT software based on 3D models. The adopted numerical scheme was the Navier–Stokes equation with k–ω SST turbulence modeling. The dynamic mesh and user-defined function (UDF) were used to revolve the rotor turbine via wind. The results indicated that the FX63-137 airfoil profile showed a higher performance in terms of the lift-to-drag ratio compared to the other airfoils. The optimum axial distance between the two rotors was 0.087 m of the rotor diameter and the efficiency of the new CRRAT increased to almost 45% compared to the single-rotor RAT. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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Review

Jump to: Research

16 pages, 906 KiB

Open AccessReview

Neural Networks for Improving Wind Power Efficiency: A Review

by Heesoo Shin, Mario Rüttgers and Sangseung Lee

Fluids 2022, 7(12), 367; https://doi.org/10.3390/fluids7120367 - 28 Nov 2022

Cited by 3 | Viewed by 2429

Abstract

The demand for wind energy harvesting has grown significantly to mitigate the global challenges of climate change, energy security, and zero carbon emissions. Various methods to maximize wind power efficiency have been proposed. Notably, neural networks have shown large potential in improving wind [...] Read more.

The demand for wind energy harvesting has grown significantly to mitigate the global challenges of climate change, energy security, and zero carbon emissions. Various methods to maximize wind power efficiency have been proposed. Notably, neural networks have shown large potential in improving wind power efficiency. In this paper, we provide a review of attempts to maximize wind power efficiency using neural networks. A total of three neural-network-based strategies are covered: (i) neural-network-based turbine control, (ii) neural-network-based wind farm control, and (iii) neural-network-based wind turbine blade design. In the first topic, we introduce neural networks that control the yaw of wind turbines based on wind prediction. Second, we discuss neural networks for improving the energy efficiency of wind farms. Last, we review neural networks to design turbine blades with superior aerodynamic performances. Full article

(This article belongs to the Special Issue Wind and Wave Renewable Energy Systems, Volume II)

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