Continued operation of delta-connected AC motor-drive systems under short-circuit fault

Continued operation of motor drive systems under a short-circuit fault in one of the motor windings is discussed and analyzed in this paper. At this operating condition, the fault current may have a very high value which may instantaneously burn the motor windings and cause immediate catastrophic failure. Therefore, these severe fault conditions are analyzed in depth by the utilization of a commercial Time stepping Finite Element program which incorporates the effect of core saturation, interaction between the controller and the motor space harmonics. The effect of applying a recently presented fault mitigation strategy for a Delta-connected motor-drive system on the system performance and the circulating short-circuit current in the motor stator windings are also analyzed and discussed.