Stator Inter Turn fault diagnosis by High-Frequency Modeling of Inverter Fed Induction Motor

In this paper, a high-frequency model for inter-turn short circuit fault in the inverter-fed induction motor is proposed. The proposed model can be used to investigate the inter-turn short circuit motor behavior at the high and low frequency simultaneously while the machine is fed from an inverter. This model is suitable to evaluate the fault features for stator inter-turn short circuit and to predict overvoltage transients and leakage current in an inverter-fed induction machine. The high-frequency parameters of the proposed faulty model have been computed from the common-mode impedance and differential mode impedance of the motor. A dq motor model with an inter-turn short circuit fault is used to get the response at low frequency. Line current of the motor has been acquired to perform discrete wavelet analysis, and various statistical parameters have been calculated on different levels of decomposition to extract the fault features. Simulation and hardware analysis proves that the combination of db1 wavelet and L2-Norm of sixth level detailed coefficient gives the best feature of inter-turn fault.