Nacelle orientation based health indicator for wind turbines

A nacelle is the center hub of a wind turbine, with blades attached to it, and it is a key component to be controlled to ensure that the wind turbine face the incoming wind to capture the most energy. Ideally, the nacelle orientation and the wind direction should be opposite to each other. However, a noneffective control system may not be able to adjust the nacelle to its proper position, which can be a soft failure; or, in the worst case scenario like a spindle failure, the nacelle orientation is completely fixated at one direction since the turbine is shut down, which is a hard failure. Besides the well-known diagnostics tools using power and wind data to estimate the health state of a wind turbine, nacelle orientation is yet another informative variable to be added to the set of diagnostics tools, especially to detect the soft failures. In the SCADA (supervisory control and data acquisition) data set of wind turbines, there are dozens of measurement variables, on ambient weather, power, other electrical quantities, and some mechanical quantities. We have observed that the nacelle orientation exhibits a much more irregular or volatile pattern than the other variables, but the relationship between the wind direction and nacelle orientation is still effective to indicate an abnormal health state. We develop a metric to use nacelle orientation as the health indicator of wind turbines, and evaluate it using the data of nearly a hundred of wind turbines at a wind farm. Our method to construct the health indicator by nacelle orientation is driven by the SCADA data, without any pre-determined modeling, and hence it is automatic, adaptive and widely applicable on arbitrary number of wind turbines.