Efficient index for detecting the stator winding interturn fault in six-phase squirrel-cage induction motors

Abstract

Multi-phase electrical machines have recently drawn growing attention, among which; six-phase squirrel-cage induction motors (6PIMs) have gained a considerable share. 6PIMs are main candidates to be utilized in hybrid vehicles, electrical trains, ships, submarines, etc. Incipient fault diagnosis is an essential technology, which enables preventing serious damages to the machines and catastrophic interruption of them. The stator winding interturn fault is among the main incipient faults. Although, numerous studies have dealt with this fault in three-phase induction motors, there is a few studies concerning the 6PIMs. In this paper, the winding function approach is utilized to model, simulate and analyse the performance of the 6PIM with interturn fault in a stator phase winding. After examining the simulation results, an analytical method is followed to extract efficient graphic and quantitative indices for detecting the stator interturn fault and for evaluating its severity. The indices require sampling the stator phase currents only in one fundamental period, enable identifying the faulty stator phase, show good sensitivity to the fault severity and are almost insensitive to the load torque change. The stator voltage unbalance cannot mislead the fault detection method based on the indices. Various simulation and corresponding experimental test results confirm these merits.