On Shortening the Numerical Transient in Time-Stepping Finite Element Analysis of Induction Motor Under Inter-Turn Short Circuit Fault Faults

An induction motor inter-turn short circuit fault usually occurs due to the stator winding insulation failure and spreads from only a few turns in its incipient stage, to a higher number of turns. The Time-Stepping Finite Element (TS-FE) analysis is amongst the most preferred techniques for modeling induction motors under inter-turn short circuit fault. However, such a technique suffers from lengthy numerical transients, before convergence to steady-state solutions are reached. In this paper, the computational burden due to such a lengthy numerical transient in TS-FE simulation of such an induction motor under inter-turn short circuit faults, is mitigated. This is accomplished through the so-called “Virtual Blocked Rotor (VBR)” approach. Also, using the results obtained from the VBR-based TS-FE analysis of such a faulty induction motor, an inter-turn fault index is extracted using a Phase Locked Loop (PLL) assisted Magnetic Field Pendulous Oscillation (MFPO) swing angle. This modified MFPO does not need monitoring of the phase voltages to extract the fault related swing angle (or fault index).