Modelling and Detection of Stator Incipient Open Circuit Fault in Three-Phase Induction Motor

This paper presents an approach for identification of stator winding open circuit fault in induction motor based on the d-axis versus q-axis current plot. Initiation of open circuit in one of the stator windings causes unbalanced winding condition, which forces the motor to draw unbalanced current from the supply. This unbalance in stator current reflects in dq0 transformed stator current components and is used to detect the development of open circuit fault. The d-axis versus q-axis current plot is circular in nature during healthy condition of the motor and at faulty condition, the plot reshaped to an ellipse. The inclination of major axis of ellipse with reference to x-axis changes with fault severity. A MATLAB/Simulink model of a line fed three-phase induction motor is developed to study the motor behavior during fault. Simulation model of induction motor for open circuit fault and the fault detection technique revalidated by experimental results in real-time.