Rotor inter-turn short circuit fault detection in wound rotor induction machines

The aim of this paper is to develop a technique for detecting a real rotor inter-turn short-circuit fault in a wound rotor induction machine working as generator by using the spectral and the bispectral analysis. The stator currents provide interesting signatures since the rotor inter-turn short-circuit fault introduces new harmonics in the stator windings. Hence, in this paper, it is proved that sensing one stator current by using a current sensor is possible techniques for detecting this kind of electrical fault. This technique is based on mmf, flux and emf computation for both healthy and faulty machines during any operating condition. Then, by using the spectral and the bispectral analysis, the computed harmonics of stator currents are experimentally verified on a 5.5kW-220V/380V-50Hz-8 poles wound-rotor induction machine working in both healthy and faulty modes at different load conditions.