Unbalanced fault diagnosis of rotor winding in doubly-fed induction generator

The doubly-fed induction generator rotor winding links to an external circuit and carries its own frequency converter, and considering this structure, a method for initial unbalanced fault diagnosis of rotor winding of the doubly-fed induction generator is proposed. This method took the instantaneous power signal of the stator as the research object. Firstly, theory was applied to deduce the characteristic frequency of the fault when the rotor winding was unbalanced, and a PSCAD simulation model was built to verify the feasibility. In order to further prove the advantages of the diagnosis research object, the dynamic simulation experiment was implemented to compare the failure of the rotor current and stator instantaneous power corresponding to the amplitude of the characteristic frequency before and after the same degree of fault. Finally, with the intention of optimizing the diagnostic results, wavelet energy spectrum was used to calculate the stator instantaneous power failure characteristic band energy to the signal energy ratio. The results show that this ratio has high sensitivity and reliability in the diagnosis of initial unbalanced rotor winding faults in the doubly-fed induction generator. © 2020, Harbin University of Science and Technology Publication. All right reserved.