Ultimate load characteristics of NREL 5-MW offshore wind turbines with different substructures

Kim, Bae‐sung; Jin, Ji-Won; Bitkina, Olga; Kang, Ki-Weon

doi:10.1002/er.3430

Cited by 9 publications

(4 citation statements)

References 12 publications

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“…The ultimate loads of the offshore wind turbine were analyzed under steady state wind condition at each wind speed. This is because marine environmental loads such as turbulence, irregular waves, and currents generate complex vibrations depending on the substructure, and eventually affect the ultimate load of the superstructure [17]. In addition, steady state wind conditions can reduce analytical errors with regards to the complexity of dynamic response loads of the offshore wind turbine.…”

Section: Ultimate Load Analysis Conditionmentioning

confidence: 99%

Allowable Pitch Angle of Aerodynamic Imbalance Due to Individual Pitch Movement for Ultimate Loads on Offshore Wind Turbine Using Artificial Neural Network

Kim¹,

Jung

Jang

et al. 2022

Applied Sciences

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This study aims to calculate the ultimate loads through integrated load analysis under aerodynamic imbalance by individual pitch movement of offshore wind turbines, and based on this, to identify the allowable region of the individual pitch angle of the blade. For this, 5 MW offshore wind turbines were modeled using GH-BladedTM based on jacket type substructure data of the NREL-5 MW generic model and Upwind reports. For integrated load analysis, wind speeds were selected: 11 m/s, 14 m/s, 17 m/s, 20 m/s, 22 m/s, and 24 m/s. Ultimate load analysis was performed through the fixed pitch control mode with the individual pitch angles at an interval of 2°, ranging from 0° to 30°. Analysis was performed for the collective pitch control under the same environmental conditions as IPC. Through the comparison of loads at hub for CPC and the individual pitch movement states calculated through integrated load analysis, we identified the allowable pitch angle region where the ultimate loads of the individual pitch movement conditions were less than those of the CPC conditions. Furthermore, pattern analysis was performed using the artificial neural network for numerical modeling of the allowable pitch angle region. The results confirmed a high success rate of over 99%. Based on these results, this study suggested a new model according to the wind speed for the allowable pitch angle region.

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Section: Ultimate Load Analysis Conditionmentioning

confidence: 99%

Allowable Pitch Angle of Aerodynamic Imbalance Due to Individual Pitch Movement for Ultimate Loads on Offshore Wind Turbine Using Artificial Neural Network

Kim¹,

Jung

Jang

et al. 2022

Applied Sciences

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“…Presently, the extensively studies about the coupling mechanism of typical bottom-fixed and floating OWTs are carried out by researchers using the previously described simulation tools. For example, Kim et al (2016) established the fully coupled numerical model of a monopile and jacket OWT in GH Bladed and investigated the differences in the structural responses between the monopile and jacket OWT. Ren et al (2022) carried out the dynamic analysis of a multicolumn tension leg platform floating OWT under operational and extreme environmental conditions in FAST v7 and investigated the tendon failure to examine the performance of OWT based on the accidental limit states specified in the design code DNV-RP-0286.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of dynamic characteristics of an ultra-large jacket offshore wind turbine under wind and wave loads using aero-hydro-structural elastic similarities

Xiong

Pan²,

Wang³

et al. 2023

Front. Energy Res.

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Owing to the difficulties in the scaled rotor-nacelle assembly (RNA) and support structure design, and alleviation of small scaling effects, the limited dynamic model tests are conducted for the jacket offshore wind turbines (OWTs), which are extensively constructed in the offshore wind farms located in the depth of 40–50 m. To address this limitation, an integrated test method based on aero-hydro-structural elastic similarities is proposed in this study. It comprises a performance-scaled RNA model and a scaled support structure model. A redesigned blade model is adopted in the scaled RNA model to ensure the similarities of aerodynamic thrust loads without modifications of the scaled test winds. Moreover, auxiliary scaled drivetrain and blade pitch control are designed to simulate the operational states of a practical OWT. The scaled model of the OWT support structure is fabricated based on the joint hydro-structural elastic similarity, and the small scaling effects are mitigated by introducing sectional bending stiffness similarities. Subsequently, the dynamic model tests of an ultra-large jacket OWT under wind-only, wave-only, and combined wind and wave conditions are carried out. The accuracy of the fabricated OWT test model is validated based on the recorded responses, and the influence of the dominant frequencies on the dynamic responses of the OWT model is quantitatively evaluated using the wavelet packet-based energy analysis method. Further, the coupling mechanisms of the scaled OWT model under typical wind and wave loads are investigated, and the interactions between the environmental loads and OWT motions are proved.

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“…A detailed description of the characteristics of the NREL 5 MW wind turbine is presented in the work of Jonkman et al [8]. Moreover, regarding classification of the wind turbine according to the criteria proposed by the International Electrotechnical Commission (IEC), the NREL 5 MW wind turbine belongs to the class IIA, see Kim et al [30]. For the modelling of the pitch control system of the wind turbine, the linearization tool of the open-source aeroelastic code FAST v7 [31] has been used, which has been designed by the NREL.…”

Section: Introductionmentioning

confidence: 99%

Kharitonov Theorem Based Robust Stability Analysis of a Wind Turbine Pitch Control System

et al. 2020

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Wind energy has recently become one of the most prominent technologies among electrical energy generation systems. As a result, wind-based renewable energy generation systems are incessantly growing, and wind turbines of different characteristics are being installed in many locations around the world. One drawback associated with different characteristics of the wind turbines is that controllers have to be designed individually for each of them. Additionally, stable performance of the wind turbines needs to be ensured in the whole range of their operating conditions. Nowadays, there are many causes for uncertainties in the actual performance of a horizontal axis wind turbine, such as variations in the characteristics of the wind turbine, fabrication tolerances of its elements or non-linearities related to different operating-points. Hence, in order to respond to these uncertainties and ensure the stability of the wind turbine, robust control and stability theories have been gaining importance during recent years. Nevertheless, the use of robust stability analyses with complex wind turbine models still needs to be faced and remarkably improved. In this paper, a stability analysis of the pitch system control of a horizontal axis wind turbine based on the Kharitonov robust stability method is proposed. The objective was to assess the robust stability of a pitch controller in response to uncertainties arising from varying operating conditions of the National Renewable Energies Laboratory (NREL) 5 MW class IIA wind turbine. According to the results, the proposed method could satisfactorily respond to limited variations in the characteristics of the model, but could lack accuracy in cases of bigger variations or employment of high order complex mathematical models.

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Ultimate load characteristics of NREL 5-MW offshore wind turbines with different substructures

Cited by 9 publications

References 12 publications

Allowable Pitch Angle of Aerodynamic Imbalance Due to Individual Pitch Movement for Ultimate Loads on Offshore Wind Turbine Using Artificial Neural Network

Allowable Pitch Angle of Aerodynamic Imbalance Due to Individual Pitch Movement for Ultimate Loads on Offshore Wind Turbine Using Artificial Neural Network

Experimental study of dynamic characteristics of an ultra-large jacket offshore wind turbine under wind and wave loads using aero-hydro-structural elastic similarities

Kharitonov Theorem Based Robust Stability Analysis of a Wind Turbine Pitch Control System

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