Electrothermal Modelling of Squirrel Cage Induction Machine with Winding Fault Analysis

Electrothermal analysis has great potential as an approach for monitoring the health of electric machines. The thermal analysis gives precise information for early fault detection. An insulation deterioration in machine winding creates a short circuit which leads to an inter-turn fault and, if not discovered, phase-phase fault or phase-ground fault may occur. To understand the electrical and thermal behaviour of machines under various stages of fault conditions, electrothermal modelling is mandatory. This paper develops the electrothermal model of a 2.2 kW squirrel cage induction machine with various winding faults in the Matlab/Simulink platform. Based on simulation findings the phase currents and short circuit loop current spikes under different fault scenarios and load conditions were derived. To evaluate the impact of faults on machine behaviour, variations in electrical and thermal characteristics under healthy and faulty systems were analyzed. The symmetrical and asymmetrical winding faults including single-phase faults, two-phase faults and three-phase faults were created with 2% and 6% severity.