Current-Based Fault Index for Induction Motor Inter-Turn Short Circuit Fault Analysis

The wide use of induction machines in industries make them more prone to different types of faults. Out of all, 30- 40% are stator faults, which mostly starts from inter turn fault. Inter turn short circuit (ITSC) fault in early stage is undetectable but prone to develop into more severe faults like phase-to-ground or phase-to-phase faults. However, it can be detected in the negative sequence current and current harmonics, which make them suitable to use in ITSC fault diagnosis. In this paper, a fault index is proposed utilizing two different fault features of stator current i.e., negative sequence current (NSC) and current harmonic component (CHC). Finite element method (FEM) based models are developed for the simulation of induction machine with several degree of inter turn faults. The ITSC fault is implemented in one of the phase of the machine. From the results obtained from the simulations, the aforementioned fault index is analyzed for different fault levels.