Assessment of wind turbine drive-train fatigue loads under torsional excitation

Gallego‐Calderon, Juan; Natarajan, Anand

doi:10.1016/j.engstruct.2015.09.008

Cited by 26 publications

(11 citation statements)

References 18 publications

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“…Each gear is supported by flexible bearings represented also as linear springs. The complete list and assumptions and details about the mathematical model were previously presented in the study of Gallego‐Calderon and Natarajan . The stiffness matrix (given as equation ) corresponding to the bearings is obtained based on their physical parameters as presented by Lim and Singh and implemented within a wind energy context in the study of Gallego‐Calderon et al .…”

Section: Methods and Modelsmentioning

confidence: 99%

“…Along with the established cases in the IEC standard 61400‐1 such as DLC 2.3 and 5.1, the grid code requirements are considered by including a LVRT in the DLC 1.1 simulation. The study is carried out using an electromechanical approach where a detailed wind turbine structure (modeled with HAWC2) and a detailed drivetrain that includes the gearbox and the generator dynamics (modeled in MATLAB/Simulink) are coupled in a co‐simulation environment . The effect of the extreme events is quantified in the gearbox bearings in terms of their maximum loads under different wind conditions.…”

Section: Introductionmentioning

confidence: 99%

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Ultimate design load analysis of planetary gearbox bearings under extreme events

2016

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This paper investigates the impact of extreme events on the planet bearings of a 5 MW gearbox. The system is simulated using an aeroelastic tool, where the turbine structure is modeled, and MATLAB/Simulink, where the drivetrain (gearbox and generator) are modeled using a lumped‐parameter approach. Three extreme events are assessed: low‐voltage ride through, emergency stop and normal stop. The analysis is focused on finding which event has the most negative impact on the bearing extreme radial loads. The two latter events are carried out following the guidelines of the International Electrotechnical Commission standard 61400‐1. The former is carried out by applying a voltage fault while simulating the wind turbine under normal turbulent wind conditions. The voltage faults are defined by following the guidelines from four different grid codes in order to assess the impact on the bearings. The results show that the grid code specifications have a dominant role in the maximum loads achieved by the bearings during a low‐voltage ride through. Moreover, the emergency brake shows the highest impact by increasing the bearing loads up to three times the rated value. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Methods and Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultimate design load analysis of planetary gearbox bearings under extreme events

2016

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“…With advanced multibody simulation tools, it is also possible to model all elements of the drivetrain fully coupled to the aeroelastic interactions of the rotor (Gallego-Calderon and Natarajan, 2015;Gallego-Calderon et al, 2017;Wang et al, 2020) and mounted on a flexible tower. In such a software tool, the drivetrain is subject to continuous wind-driven excitation and grid-driven events.…”

Section: Remaining Useful Lifementioning

confidence: 99%

Wind turbine drivetrains: state-of-the-art technologies and future development trends

Nejad

Keller

Guo

et al. 2021

Preprint

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Abstract. This paper presents the state-of-the-art technologies and development trends of wind turbine drivetrains – the energy conversion systems transferring the kinetic energy of the wind to electrical energy – in different stages of their life cycle: design, manufacturing, installation, operation, lifetime extension, decommissioning, and recycling. Offshore development and digitalization are also a focal point in this study. The main aim of this article is to review the drivetrain technology development as well as to identify future challenges and research gaps. Drivetrain in this context includes the whole power conversion system: main bearing, shafts, gearbox, generator, and power converter. The paper discusses current design technologies for each component along with advantages and disadvantages. The discussion of the operation phase highlights the condition monitoring methods currently employed by the industry as well as emerging areas. This article also illustrates the multidisciplinary aspect of wind turbine drivetrains, which emphasizes the need for more interdisciplinary research and collaboration.

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“…to minimize resonant torsional vibrations in a drivetrain caused by variations in wind velocity. In another study, a lumped parameter model of the gearbox with HAWC2 was simulated to investigate the planet bearings damage equivalent loads. The representation of components as a multi‐body system reduces the number of DOFs in comparison with FE models, but level of accuracy is still good enough to represent the drivetrain in a realistic manner.…”

Section: Introductionmentioning

confidence: 99%

Identification of loading conditions resulting in roller slippage in gearbox bearings of large wind turbines

Dąbrowski

Natarajan

2017

Wind Energy

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The dynamic loads on the rollers inside the bearings of large wind turbine gearboxes operating under transient conditions are presented with a focus on identifying conditions leading to slippage of rollers. The methodology was developed using a multi-body model of the drivetrain coupled with aeroelastic simulations of the wind turbine system. A 5 MW reference wind turbine is considered for which a three-stage planetary gearbox is designed on the basis of upscaling of an actual 750 kW gearbox unit. Multi-body dynamic simulations are run using the ADAMS software using a detailed model of the gearbox planetary bearings to investigate transient loads inside the planet bearing. It was found that assembly and pre-loading conditions have significant influence on the bearing's operation. Also, the load distribution in the gearbox bearings strongly depends on wind turbine operation. Wind turbine start-up and shut-down under normal conditions are shown to induce roller slippage, as characterized by loss of contacts and impacts between rollers and raceways. The roller impacts occur under reduced initial pre-load on opposite sides of the load zone followed by stress variation, which can be one of the potential reasons leading to wear and premature bearing failures.While the focus herein is on the gearbox, important WT aspects like aeroelastic interactions and control are included. Aeroelastic models allow interactions between inertial, elastic and aerodynamic forces and their servo mechanisms. Examples of aeroelastic software are FAST 10 developed by NREL, HAWC2 11 by DTU Wind Energy, Bladed 12 developed by DNV-GL and AdWiMo 13 by MSC Software. These calculate WT loads and response in the time domain on the basis of input environmental conditions, but usually, in these models, the gearbox dynamics are neglected. 14 The detailed models for drivetrain components, usually for gearboxes, can be built by lumped parameter models, multi-body system or finite element (FE) method. These models allow simulation of the internal loading resulting from dynamical interactions in the drivetrain. It is important to determine the level of complexity required to balance between accuracy and computational efficiency. According to Guo et al., 15 for drivetrain modeling, the gearbox alone is insufficient to capture component loads and motions; coupling with the main bearing and generator is important. For simulation of loads in a gearbox, it is important to include the clearance in bearings and pre-load, which can influence the non-torque load transfer path, as well as deformations of housing and carrier that can change bearing loads. From the point of view of excitation sources, besides the torque input, the non-torque loads and gravity are relevant. 15 Oyague 14 has presented the state of the art on simulation codes for WT's gearboxes. The author has shown four stages of drivetrain modeling due to model complexity. A purely torsional model of WT drivetrain based on the lumped parameter system with 5 degrees of freedom (DOFs) was used by Mandic...

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Assessment of wind turbine drive-train fatigue loads under torsional excitation

Cited by 26 publications

References 18 publications

Ultimate design load analysis of planetary gearbox bearings under extreme events

Ultimate design load analysis of planetary gearbox bearings under extreme events

Wind turbine drivetrains: state-of-the-art technologies and future development trends

Identification of loading conditions resulting in roller slippage in gearbox bearings of large wind turbines

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