On model-based system approach for health monitoring of drivetrains in floating wind turbines

This paper deals with the health monitoring of a wind turbine drivetrain in a system perspective. A 5-MW reference drivetrain installed on a spar type floating wind turbine is selected. Degradation and damage in the main bearing which carries the axial loads can cause severe damage inside the gearbox as it causes non-torque loads entering the gearbox. Therefore, monitoring of the main bearing is very important. In this paper, different fault cases of the main bearing are considered and responses are obtained by the multi-body simulation. Gearbox failure is then evaluated in two different perspectives: one from the main bearing itself by analysing vibration, and one through studying the remaining fatigue life of another bearing inside the gearbox. The results reveal that not only the local vibration of the main bearing housing is important, but also the consequence of this degradation on other components can be a key factor in the “system” failure. This is a step forward in monitoring the wind turbine drivetrains on a system level