A proposed criteria to identify wind turbine drivetrain bearing loads that induce roller slip based white-Etching cracks

2021 ◽  
Author(s):  
Anand Natarajan ◽  
W. Dheelibun Remigius ◽  
Yi Guo ◽  
Jonathan Keller
Keyword(s):  
Wind Turbine ◽  
White Etching Cracks ◽  
Bearing Loads

scholarly journals Analysis of Wind-Turbine Main Bearing Loads Due to Constant Yaw Misalignments over a 20 Years Timespan

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1768 ◽  
Author(s):  
Martin Cardaun ◽  
Björn Roscher ◽  
Ralf Schelenz ◽  
Georg Jacobs
Keyword(s):  
Wind Turbine ◽  
Wind Farms ◽  
Wake Flow ◽  
Energy Output ◽  
Main Bearing ◽  
Load Distributions ◽  
Wind Speed Distribution ◽  
Bearing Loads ◽  
Compact Design ◽  
Multi Body

The compact design of modern wind farms means that turbines are located in the wake over a certain amount of time. This leads to reduced power and increased loads on the turbine in the wake. Currently, research has been dedicated to reduce or avoid these effects. One approach is wake-steering, where a yaw misalignment is introduced in the upstream wind turbine. Due to the intentional misalignment of upstream turbines, their wake flow can be forced around the downstream turbines, thus increasing park energy output. Such a control scheme reduces the turbulence seen by the downstream turbine but introduces additional load variation to the turbine that is misaligned. Within the scope of this investigation, a generic multi body simulation model is simulated for various yaw misalignments. The time series of the calculated loads are combined with the wind speed distribution of a reference site over 20 years to investigate the effects of yaw misalignments on the turbines main bearing loads. It is shown that damage equivalent loads increase with yaw misalignment within the range considered. Especially the vertical in-plane force, bending and tilt moment acting on the main bearing are sensitive to yaw misalignments. Furthermore, it is found that the change of load due to yaw misalignments is not symmetrical. The results of this investigation are a primary step and can be further combined with distributions of yaw misalignments for a study regarding specific load distributions and load cycles.

scholarly journals Damage characterisation of white etching cracks in a black oxide coated wind turbine gearbox bearing

Wear ◽  
2019 ◽  
Vol 432-433 ◽  
pp. 102923 ◽  
Author(s):  
H.A. Al-Tameemi ◽  
H. Long ◽  
R.S. Dwyer-Joyce
Keyword(s):  
Wind Turbine ◽  
Wind Turbine Gearbox ◽  
White Etching Cracks ◽  
Black Oxide

Quasi-Exact-Constraint Design of Wind Turbine Gearing

2010 ◽  
Author(s):  
Hani A. Arafa ◽  
Mostafa Bedewy
Keyword(s):  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Gear Tooth ◽  
Elastic Deformations ◽  
Helical Gears ◽  
Design Concepts ◽  
Cylindrical Gears ◽  
The Past ◽  
Bearing Loads ◽  
Exact Constraint

In the past two decades the wind turbine industry has witnessed a considerable number of catastrophic accidents, many of which were due to gearbox failure. Ever increasing power ratings at decreased rotor speeds result in rotor torques of some million Nm. This imposes tooth loads and planet/pinion bearing loads on the order of a hundred tons within the first step-up stage. Such heavily loaded gearboxes, correctly (or rather innocently) designed according to the relevant codes, can be self-destructive. Due consideration should be given to the elastic environment in which the gears exist. Otherwise, appreciable, unsymmetrical/unequal elastic deformations in unwanted directions lead to gear tooth edge loading, in addition to overloading the bearing(s) near that edge. Designers of wind turbine gearing have in recent years identified several concepts and measures to be taken for counteracting the asymmetry of elastic deformations or mitigating their effects. In addition to giving a brief survey of such new design concepts, this paper suggests the use of selected types of curved-tooth cylindrical gears (so-called C-gears), primarily for their self-aligning capability; they allow four degrees of freedom (4-DOF), in contrast to the 3-DOF spur and helical gears and the 2-DOF double-helical gears. In addition, these gears offer a unique set of further advantages. When used in at least the most heavily loaded, first step-up stage, the design will be rendered quasi-exactly constrained; largely tolerant of misalignment due to elastic deformations, and the gearbox reliability should be improved, by design.

scholarly journals An Integrated Approach Using Condition Monitoring and Modeling to Investigate Wind Turbine Gearbox Design

2015 ◽  
Author(s):  
Shuangwen Sheng ◽  
Yi Guo
Keyword(s):  
Wind Turbine ◽  
Condition Monitoring ◽  
High Speed ◽  
Integrated Approach ◽  
Intermediate Stage ◽  
Wind Turbine Gearbox ◽  
First Order ◽  
Bearing Loads ◽  
Design Options ◽  
Utility Scale

Vibration-based condition monitoring (CM) of geared utility-scale turbine drivetrains has been used by the wind industry to help improve operation and maintenance (O&M) practices, increase turbine availability, and reduce O&M cost. This study is a new endeavor that integrates the vibration-based CM technique with wind turbine gearbox modeling to investigate various gearbox design options. A team of researchers performed vibration-based CM measurements on a damaged wind turbine gearbox with a classic configuration, (i.e., one planetary stage and two parallel stages). We observed that the acceleration amplitudes around the first-order sidebands of the intermediate stage gear set meshing frequency were much lower than that measured at the high-speed gear set, and similar difference was also observed in a healthy gearbox. One factor for a reduction at the intermediate stage gear set is hypothesized to be the soft sun-spline configuration in the test gearbox. To evaluate this hypothesis, a multibody dynamic model of the healthy test gearbox was first developed and validated. Relative percent difference of the first-order sidebands — of the high-speed and intermediate stage gear-meshing frequencies — in the soft and the rigid sun spline configurations were compared. The results verified that the soft sun-spline configuration can reduce the sidebands of the intermediate stage gear set and also the locating bearing loads. The study demonstrates that combining vibration-based CM with appropriate modeling can provide insights for evaluating different wind turbine gearbox design options.

scholarly journals A 5 MW direct-drive generator for floating spar-buoy wind turbine: Drive-train dynamics

2016 ◽  
Vol 231 (4) ◽  
pp. 744-763 ◽  
Author(s):  
Latha Sethuraman ◽  
Yihan Xing ◽  
Vengatesan Venugopal ◽  
Zhen Gao ◽  
Markus Mueller ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Drive Train ◽  
Simulation Tool ◽  
Dynamic Feedback ◽  
Direct Drive ◽  
Main Bearing ◽  
Fully Integrated ◽  
Wind Turbine System ◽  
Bearing Loads ◽  
Response Variables

This article proceeds with investigations on a 5 MW direct-drive floating wind turbine system (FWTDD) that was developed in a previous study. A fully integrated land-based direct-drive wind turbine system (WTDD) was created using SIMPACK, a multi-body simulation tool, to model the necessary response variables. The comparison of blade pitch control action and torque behaviour with a similar land-based direct-drive model in HAWC2 (an aero-elastic simulation tool) confirmed that the dynamic feedback effects can be ignored. The main shaft displacements, air-gap eccentricity, forces due to unbalanced magnetic pull (UMP) and the main bearing loads were identified as the main response variables. The investigations then proceed with a two-step de-coupled approach for the detailed drive-train analysis in WTDD and FWTDD systems. The global motion responses and drive-train loads were extracted from HAWC2 and fed to stand-alone direct-drive generator models in SIMPACK. The main response variables of WTDD and FWTDD system were compared. The FWTDD drive-train was observed to endure additional excitations at wave and platform pitch frequencies, thereby increasing the axial components of loads and displacements. If secondary deflections are not considered, the FWTDD system did not result in any exceptional increases to eccentricity and UMP with the generator design tolerances being fairly preserved. The bearing loading behaviour was comparable between both the systems, with the exception of axial loads and tilting moments attributed to additional excitations in the FWTDD system.

scholarly journals Calculating loads and life-time reduction of wind turbine gearbox and generator bearings due to shaft misalignment

2020 ◽  
pp. 0309524X2091402 ◽  
Author(s):  
Damian P Rommel ◽  
Dario Di Maio ◽  
Tiedo Tinga
Keyword(s):  
Wind Turbine ◽  
Analytical Method ◽  
High Speed ◽  
Life Time ◽  
Universal Joint ◽  
Wind Turbine Gearbox ◽  
Bearing Failures ◽  
Shaft Misalignment ◽  
Metal Disk ◽  
Bearing Loads

During the last two decades, wind turbine industries have faced high failure rates, downtimes and costly repairs. Gearbox and generator have contributed to this, especially, because their high speed shaft bearings have often failed. In this article, an analytical method is proposed to calculate the reaction loads of flexible connecting couplings installed between wind turbine gearbox and generator. Raction loads are determined from joint kinematics and metal disk pack deformations as well as axial and angular shaft misalignment. The calculations are executed for both flexible connecting couplings and a universal joint shaft and applied to the gearbox high speed shaft. The performance of flexible connecting couplings and universal joint shaft is compared with respect to the bearing loads and life-time of the gearbox high speed shaft. It is shown that the early, unplanned bearing failures of gearbox and generator high speed shaft can often be attributed to the flexible connecting couplings installed between gearbox and generator.

Sign in / Sign up

Export Citation Format

Share Document