On-line detection of stator winding faults in controlled induction machine drives

The operation of induction machines with fast switching power electric devices puts additional stress on the stator windings what leads to an increased probability of machine faults. These faults can cause considerable damage and repair costs and - if not detected in an early stage - may end up in a total destruction of the machine. To reduce maintenance and repair costs many methods have been developed and presented in literature for an early detection of machine faults. This paper gives an overview of todaypsilas detection techniques and divides them into three major groups according to their underlying methodology. The focus will be on methods which are applicable to todaypsilas inverter-fed machines. In that case and especially if operated under controlled mode, the behavior of the machine with respect to the fault is different than for grid supply. This behavior is discussed and suitable approaches for fault detection are presented. Which method is eventually to choose, will depend on the application and the available sensors as well as hard- and software resources, always considering that the additional effort for the fault detection algorithm has to be kept as low as possible. The applicability of the presented fault detection techniques are also confirmed with practical measurements.