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

Yao Li,Caichao Zhu,Xu Chen,Jianjun Tan

doi:10.3390/en13082108

Abstract

The wind turbine drivetrain suffers significant impact loads that severely affect the reliability and safety of wind turbines. Bearings and gears within the drivetrain are critical components with high repair costs and lengthy downtime. To realistically assess the system reliability, we propose to establish an electromechanical coupling dynamic model of the wind turbine considering the control strategy and environmental parameters and evaluate the system’s reliability of wind turbine drivetrain based on loads of gears and bearings. This paper focuses on the dynamic reliability analysis of the wind turbine under the control strategy and environmental conditions. SIMPACK (v9.7, Dassault Systèmes, Gilching, Germany) is used to develop the aero-hydro-servo-elastic coupling dynamic model with the full drivetrain that considers the flexibility of the tower and blade, the stochastic loads of wind and waves, gear meshing features, as well as the control strategy. The system reliability level of wind turbine drivetrain at different wind conditions is assessed using survival signature and fault tree analysis (FTA), and the influences of strength degradation of the transmission components on the system reliability are explored. Following this, the bending fatigue reliability and contact fatigue reliability concerning different wind conditions are compared in this paper. A case study is performed to demonstrate the effectiveness and feasibility of the proposed methodology.

Highlights

Due to climate change and energy crises across the world, it is an urgent task to develop renewable energy sources to replace fossil fuels
This paper is aimed at developing the aero-elastic-servo-hydro dynamic model of a wind turbine with the full drivetrain, which considers the flexibility of tower and blades, the stochastic loads of wind and waves, the gear meshing features, as well as the control strategy
The failures of the wind turbine drivetrain often lead to high repair cost and long downtime

Summary

Introduction

Due to climate change and energy crises across the world, it is an urgent task to develop renewable energy sources to replace fossil fuels. Given the popularity of wind power, there have been continuous advancements in wind turbine technology. Most turbines are built with the variable-speed and variable blade-pitch-to-feather configuration. This configuration allows the turbine’s blades to rotate through the pitch system. In comparison with fixed-pitch wind turbines, these turbines can guarantee more stable output power and a greater wind capture efficiency with the blades acting as brakes. One downside is that the blade-pitch system frequently reacts against the stochastic wind, which is affected by the control strategy and uncertain environment, resulting in wind turbines operating under a complicated and unsteady load.

Objectives

Results

Conclusion