Complex-Vector Model of Interturn Failure in Induction Machines for Fault Detection and Identification

This paper presents an improved complex-vector dynamic model for a three-phase induction machine (IM) with stator interturn short-circuit fault. The paper proposes an accurate and meaningful approach to the faulty stator leakage inductance and describes a nonlinear phenomenon in the faulty circuit. The asymmetric model is developed in detail and represented in state-space (SS) form with the flux-linkages as the SS variable. Based on the proposed model, steady-state complex-vector, operational, and sequence component equivalent circuits are derived for fault detection and identification purposes. For reasons of verification, the model is simulated in MatLab environment and experimentally corroborated for a 1HP three-phase squirrel-cage IM. The simulations and experiments are compared at no-load and loading condition for both transient and steady-state response. The permanent regime analysis studies the model with respect to the fault severity factor, fault resistance, and load variation. The proposed model shows high correlation with the experimental results.