Investigation of Doubly-fed Induction Generator Controller Signals under Variable Speed Operating Conditions

The analysis of the controller signals of a doublyfed induction generator under variable speed operating conditions with and without generator faults is presented in the time domain in order to more accurately investigate the conditions presently experienced in wind turbines during operation. The presented study can be used to examine the capability of using the controller signals for condition monitoring and fault detection. A doubly-fed induction generator harmonic model developed in the Simulink environment is used for the investigation. It is shown that the controller signals have a high potential and could be an effective fault detection tool for wind turbine generators, as the identified changes with a fault are clearly identified especially when they are compared with the terminal signals, which are conventionally used for condition monitoring and fault detection purposes.