Different Failure Modes of the Horizontal Axis Wind Turbine Gearbox

The components and subsystems in the horizontal axis wind turbines (HAWTs) nacelle always cause the highest reliability issues. Among these subsystems, we find that the gearbox is widely used in industrial applications, due to difficult operating conditions, inevitable fatigue, and high service load defects can develop in the gearbox, if they cannot be detected early, their operation will continue to deteriorate, which causes mechanical and economic losses [1]. According to the latest reports that were made by the National Renewable Energy Laboratory (NREL) indicates that the majority of gearbox failures in the nacelle of wind turbines (76%) are caused by mechanical bearings [2]. Latterly, many studies have been done to develop gearbox dynamic models with faults sight to understand gear fault generation mechanism, and then develop real fault detection and diagnosis methods [3]. This article was to make a state of the art on the various failure modes of the horizontal axis wind turbine gearbox, first, we will make a comparative study between vertical axis wind turbines and HAWTs wind turbines, then we will give a comprehensive approach to get closer to reality, analyze the different failure modes of the HAWT gearbox we will present the different models for the dynamic modeling of gearbox failures, detection and diagnosis and present a real study carried out within a Moroccan company.