Fault Detection of Interturn Short Circuit in Induction Motors Under Nonstationary Conditions and Unbalanced Supply Voltage

Stator winding inter-turn short circuit (ITSC) is a typical fault in induction motors, which may lead to severe winding damage or even burn the motor. However, ITSC detection faces significant challenges as fault characteristics can be easily confused with those generated by the unbalanced supply voltage and are prone to fluctuate under non-stationary conditions. This paper proposes a strategy for ITSC detection and faulty phase identification using only stator voltage signals. First, an algorithm called cost function-iterative amplitude and frequency modulation (CF-IAFM), consisting of instantaneous frequency ridge initialization and iterative updating, is proposed to provide the precise instantaneous frequency ridge of voltage signals. Second, to solve the problem of false alarms caused by complex operating conditions, a fault detection indicator called extended zero-sequence voltage factor (EZVF) is constructed. Further, a faulty phase identification scheme put forward only requires voltage signals. Finally, experiments and comparisons have been conducted to assess the performance of the proposed scheme. The proposed strategy exhibits high effectiveness and reliability for ITSC detection and faulty phase identification under varying operating conditions and unbalanced supply voltage.