Ultimate design load analysis of planetary gearbox bearings under extreme events

Abstract

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.

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

“…Wind turbine drivetrains are subject to dynamic loading from a wide range of operating conditions caused by wind shear, veer, turbulence, and gusts; changes in the turbine operational state; grid faults; and nacelle motions; therefore, it is essential that the computational models for the drivetrain consider the dynamics of the rotor and the demands of the grid through the converter. Such an electromechanical model captures the aeroelastic interactions of the rotor and characterizes the voltage/current excursions in the generator because of grid requirements (Gallego-Calderon et al, 2017;Bruce et al, 2015;Blockmans et al, 2013).…”

“…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.…”

A review of wind turbine drivetrain loads and load effects for fixed and floating wind turbines

“…The mechanical loads acting on wind turbine structures are primarily a result of several interactions that involve: (1) aero‐servo‐elastic interactions (Hansen, 2007) of the rotor with the inflow, (2) hydroelastic interactions of offshore substructures (Chen et al, 2006) when the wind turbine is installed offshore, and (3) electro‐mechanical interactions of the drivetrain (Gallego‐Calderon et al, 2017) with the grid connection. Besides these primary causes of mechanical loading, other sources such as due to earthquakes, blade ice, impacts of air‐borne or water‐borne bodies also occur.…”

“…However even normal turbine operations can result in component failure limits states being exceeded, due to which the design of the drivetrain must be such that all potential load case situations and grid conditions are included. Typical normal load situations that impact the drivetrain are due to wind turbulence (Mann, 1994), wind direction change, extreme wind shear (TC88‐MT, 2005), grid faults (Gallego‐Calderon et al, 2017) and occurrences of storms. A combination of such events such as wind direction change with grid fault may be abnormal or normal depending on the location of wind turbine installation and treated specifically.…”

Fatigue Reliability Analysis of Wind Turbine Drivetrain Considering Strength Degradation and Load Sharing Using Survival Signature and FTA

“…Jiang et al [18] calculated the fatigue damage of the planet bearing of a wind turbine gearbox under different wind speed distributions using HAWC2 (Horizontal Axis Wind turbine simulation Code 2nd generation, v2, DTU Wind Energy, Lyngby, Denmark), SIMPACK, and Calyx (The three-dimensional finite element code, v1, Advanced Numerical Solutions LLC, Hilliard, OH, USA). Calderon et al [19] built a dynamic model of the gearbox using the lump-parameter method and explored the dynamic behavior of the planet bearing under extreme loads.…”