Research on fault diagnosis of asymmetric stator winding for doubly-fed induction generators

Abstract

Magnetic field distribution, negative-sequence stator current, stator phase-angle difference between phase currents, and instantaneous rotor power were studied by theoretical analysis, modeling and simulation, experiment after stator winding fault in doubly-fed induction generators. Firstly, On the basis of analyzing the variation of magnetic field and stator current after stator winding inter-turn short circuit fault based on the finite element method, the variation of negative-sequence stator current and stator phase-angle difference between phase current were analyzed and studied. Grid model of doubly-fed induction generator was established in PSCAD, and through signal analysis it’s found that the sensitivity and reliability of instantaneous rotor power spectrum are not only much better than those of current spectrum, voltage spectrum, but also better than those of negative-sequence component of stator current in slight fault diagnosis of stator winding. Finally, the experimental platform of stator winding fault for doubly-fed induction generator was built in the dynamic model laboratory of Hohai University, which further verified the reliability and superiority of instantaneous rotor power spectrum. So the synthetic diagnosis of stator winding fault for doubly-fed induction generator based on instantaneous rotor power with negative-sequence stator current and phase-angle difference between phase current is proposed.