Stator inter-turn faults diagnosis in induction motors using zero-sequence signal injection

Abstract

This study presents a strategy for stator inter-turn faults diagnosis in induction motors (IMs) operating under timevariable load and time-variable speed conditions. The strategy consists in injecting a zero-sequence high-frequency signal in order to analyse variations in the stator inductances. Incipient stator inter-turn faults are detected by a simple signal processing of the derivatives of the currents. A feature of the strategy is that the zero-sequence high-frequency signal is generated by the inverter that feeds the machine, without modifying the standard space vector modulation of the IM-drive. Experimental results show that faults representing <1% of the stator winding can be detected, as well as the phase location of the fault, validating this proposal.