Condition monitoring of windturbines

A method for monitoring a wind turbine, comprising:

• defining a first subsystem of the wind turbine;
• providing a simulation model for the first subsystem;
• receiving, during normal operation of the wind turbine, an input signal and an actual output signal of the first subsystem;
• determining an expected output signal of the first subsystem using the input signal as an input of the simulation model, and mapping the input signal with a first transfer function to the expected output signal;
• comparing the actual output signal and the expected output signal;
• determining, based on the comparison between the actual output signal and the expected output signal, if the first subsystem operates within a given specification;
• and
• determining a second transfer function so that the input signal and the expected output signal substantially match,
• wherein comparing the actual output signal and the expected output signal comprises determining a distance between the first transfer function and the second transfer function in a function space.

A system for monitoring a wind turbine, comprising a simulation module which is configured:

• to simulate, during normal operation of the wind turbine, a behavior of a subsystem of the wind turbine by mapping an input signal with a first transfer function to an expected output signal;
• to determine, based on the simulated behavior, if the subsystem operates within a given specification by comparing an actual output signal of the subsystem with the expected output signal from the simulation module, determining if the actual output signal and the expected output signal substantially match, and wherein determining if the actual output signal and the expected output signal substantially match comprises determining a second transfer function so that the input signal and the expected output signal substantially match, and comparing the actual output signal and the expected output signal comprises determining a distance between the first transfer function and the second transfer function in a function space changing the first transfer function when the actual output signal and the expected output signal do not substantially match to achieve a substantial match;
• and
• to send a message to a turbine controller of the wind turbine when the subsystem is determined not to operate within the given specification based on the changed first transfer function.