Online Model-Based Stator-Fault Detection and Identification in Induction Motors

In this paper, a model-based strategy for stator-interturn short-circuit detection on induction motors is presented. The proposed strategy is based on the generation of a vector of specific residual using a state observer. The vectorial residual is generated from a decomposition of the current estimation error. This allows for a fast detection of incipient faults, independently of the phase in which the fault occurs. Since the observer includes an adaptive scheme for rotor-speed estimation, the proposed scheme can be implemented for online monitoring, by measuring only stator voltages and currents. It is shown that the proposed strategy presents very low sensitivity to load variations and power-supply perturbations. Experimental results are included to show the ability of the proposed strategy for detecting incipient faults, including a low number of short-circuited turns and low fault current.