Stator Faults Detection on Induction Motors Using Harmonic Sequence Current Components Analysis

In this paper we propose a strategy for detecting interturn short-circuit faults on stator windings of induction motors (IM). The strategy is based on an analytical model thatincludes a stator fault in any of the phase windings considering the h-th harmonic in the supply voltage. To find the adequate model, we propose an equivalent electrical circuit of the IM in steady state, considering each sequence component. The proposed strategy allows the detection of an interturn short-circuit fault by monitoring the fifth-order harmonic component. We present simulation and experimental results for the IM with fault in different operating conditions. In the laboratory tests, we use a programmable power supply in order to synthesize waveforms of variable amplitude and frequency, and an IM with modified stator windings to generate different fault severities and validate the proposed model. The results show that the sustained increase of the fifth-order harmonic of positive-sequence current is a good indicator of the fault severity.