Inter-turn short circuit fault detection of wound rotor induction machines using Bispectral analysis

The aim of this paper is to develop a technique for detecting an inter-turn short-circuit in a wound rotor induction machine working as generator by using the bispectral analysis. Bispectral analysis is able to provide more information than power spectrum analysis. In the present investigation, the rotor and stator currents of the machine operating in both healthy and faulty modes are thoroughly analyzed. In the first stage, the bispectral analysis is applied to signals generated by a wound-rotor induction machine model developed by using MATLAB/Simulink
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environment. This model allows the simulation of the inter-turn short circuit in the stator of the machine in any system with control circuits and/or connections to the grid by means of power electronics converters. Then, the same analysis has been performed using experiments on a 5.5kW--220V/380V - 50Hz - 8 poles wound-rotor induction machine working in both healthy and faulty modes at different load conditions. Finally, a comparison between simulation and experimental results is given. Very promising results are obtained and presented. The results and the analysis indicate that bispectrum can be successfully applied to machine asymmetric faults, and stator winding fault analysis.