Control system for a wind turbine and method of operating a wind turbine based on monitoring a bearing

A method of operating a wind turbine having a bearing assembly convertible between a hydrostatic operating mode and a hydrodynamic operating mode, a shaft received in the bearing assembly, and at least one sub-system capable of altering a dynamic state of the wind turbine, comprising:

• monitoring at least one parameter indicative of a load on the shaft;
• comparing the at least one parameter to a threshold criteria;
• determining whether the bearing assembly is in a hydrostatic operating mode or a hydrodynamic operating mode;
• and
• performing at least one of the following steps when the at least one parameter meets the threshold criteria:
• i) altering the dynamic state of the wind turbine to reduce the load on the shaft when the bearing assembly is in the hydrodynamic operating mode;
• and ii) altering the state of the bearing assembly so as to better accommodate the load on the shaft when the bearing assembly is in the hydrostatic operating mode.

A wind turbine, comprising:

• a tower;
• a nacelle located adjacent a top of the tower;
• a rotor having a hub and a plurality of blades extending therefrom and configured to interact with the wind to rotate the rotor;
• a main rotary shaft coupled to the rotor and extending within the nacelle;
• a main bearing assembly positioned in the nacelle for supporting the shaft at least in part by a fluid film;
• at least one sub-system capable of altering the dynamic state of the wind turbine;
• and
• a control system for controlling the operation of the wind turbine, the control system comprising:
• a controller operatively coupled to the bearing assembly and the at least one sub-system;
• at least one sensor for monitoring at least one parameter of the fluid film indicative of a load on the shaft, the at least one sensor operatively coupled to the controller and configured to send a signal to the controller corresponding to a value in the at least one parameter,
• wherein the controller is configured to send a signal to the at least one sub-system for altering the dynamic state of the wind turbine so as to reduce the load on the shaft when the value of the at least one parameter sent by the at least one sensor satisfies a threshold criteria.