A Diagnostic Space Vector-Based Index for Rotor Electrical Fault Detection in Wound-Rotor Induction Machines under Speed Transient

This paper investigates a new approach for the detection of rotor electrical faults in three-phase wound-rotor induction machines. The method is assessed in a wind energy conversion system, where the rotor side of the wound-rotor induction machine is supplied by a static converter for the control of active and reactive power flows from the generator to the electrical grid. Here, a diagnostic space vector is presented that sensibly improves the rotor fault detection in wound-rotor induction machine by combining the spectral signatures of both rotor current and voltage space vectors. The dc component of this diagnostic space vector, that is equal to zero in healthy conditions and different from zero under rotor asymmetry, is adopted as rotor fault index. The main advantages of the proposed technique are the implementation simplicity and the capability to operate even during speed transients. The technique is also validated by means of simulation and laboratory scale experimental tests.