Abstract: The disclosure relates to condition monitoring of wind turbine pitch bearings by measuring variations in distance between inner and outer rings of a pitch bearing during an angular rotation. Example embodiments include a method of monitoring a condition of a pitch bearing (100) of a wind turbine, the pitch bearing comprising a first ring (102) attached to a blade of the wind turbine and a second ring (103) attached to a hub of the wind turbine, the method comprising: mounting a displacement sensor (105) to the pitch bearing (100) to measure a distance between the first ring (102) and the second ring (103); rotating the first ring (102) relative to the second ring (103) over an angular range; and recording an angular position (204) of the first ring (102) relative to the second ring (103) and a distance (205a, 205b) measured by the displacement sensor (105) while rotating the first ring (103) relative to the second ring (103) over the angular range.

Abstract: A method for modifying the power output of a wind turbine generator. The power output of a wind turbine generator can be modified based on the rate of fatigue and/or damage calculated for components within the wind turbine generator. Damage and/or fatigue can be calculated based on current or predicted future operating conditions. The turbine operation can be modified if the cost of damage and/or cost of fatigue is less than a value for the electricity produced. In this case, the rate of fatigue is calculated using models of the wind turbine generator or its components, where the model may be based on a metamodel or by an Equivalent Operating Hours approach.

Abstract: A method for predicting remaining useful life of a wind or water turbine or component determines in step 116 an EOH for the turbine or component and compares this in step 118 to an EOH limit obtained in step 114. This provides a simple approach to estimating remaining useful life, giving the turbine operator an indication of the condition of turbines or farms under management.

Abstract: A method for predicting remaining useful life of a wind or water turbine or component determines in step (116) an EOH for the turbine or component and compares this in step (118) to an EOH limit obtained in step (114). This provides a simple approach to estimating remaining useful life, giving the turbine operator an indication of the condition of turbines or farms under management.

Abstract: A method for predicting remaining useful life of a wind or water turbine or component determines in step 116 an EOH for the turbine or component and compares this in step 118 to an EOH limit obtained in step 114. This provides a simple approach to estimating remaining useful life, giving the turbine operator an indication of the condition of turbines or farms under management.

Abstract: A method for predicting remaining useful life of a wind or water turbine or component determines in step (116) an accumulated damage for the turbine or component and compares this in step (118) to preset damage limit obtained in step (114). This provides a simple approach to estimating remaining useful life, giving the turbine operator an indication of the condition of turbines or farms under management.

Abstract: A method for modifying the power output of a wind turbine generator. The power output of a wind turbine generator can be modified based on the rate of fatigue and/or damage calculated for components within the wind turbine generator. Damage and/or fatigue can be calculated based on current or predicted future operating conditions. The turbine operation can be modified if the cost of damage and/or cost of fatigue is less than a value for the electricity produced. In this case, the rate of fatigue is calculated using models of the wind turbine generator or its components, where the model may be based on a metamodel or by an Equivalent Operating Hours approach.

Abstract: A method for predicting remaining useful life of a wind or water turbine or component determines in step (116) an accumulated damage for the turbine or component and compares this in step (118) to preset damage limit obtained in step (114). This provides a simple approach to estimating remaining useful life, giving the turbine operator an indication of the condition of turbines or farms under management.

Abstract: A method for predicting remaining useful life of a wind or water turbine or component determines in step (116) an EOH for the turbine or component and compares this in step (118) to an EOH limit obtained in step (114). This provides a simple approach to estimating remaining useful life, giving the turbine operator an indication of the condition of turbines or farms under management.

Abstract: A method for identifying a wind or water turbine, or component thereof, for maintenance, comprises the steps of: determining an operating parameter value for the wind or water turbine; analyzing vibration data for the wind or water turbine; and comparing the vibration data with a threshold related to the operating parameter value. This approach means that vibration thresholds vary according to the expired life of wind or water turbine, leading to a more accurate identification of wind or water turbines which may be in need of maintenance, and which should be investigated.