Diagnosis of multi-turn faults of induction motor by direct detection of asymmetry admittance component

In an AC motor, the quick detection of an initially small fault is important for preventing any consequent large fault. Various detection approaches have been proposed in previous papers. This paper proposes a method for diagnosing the stator-winding faults of an induction motor by the direct detection of asymmetry admittance component. Before starting the diagnosis, the asymmetry admittances for the considered fault cases under various load conditions are obtained by simulation. The amplitude and phase of the positive- and the negative-sequence voltages, V_p and V_n, and those of currents, I_p and I_n, are extracted from the voltage and current Park vectors respectively. The asymmetry admittance, Y_a, is calculated from them. These steps are repeated for each sample time and the motor condition is diagnosed according to the variations in the Y_a value. Simulation and experimental results are also shown and the proposed method is investigated and validated.