Transient thermal models of induction machines under Inter-turn short-circuit fault conditions

Induction machines are the working horses in a lot of industries. Inter-turn short-circuit (ITSC) fault is one of the most common failure modes taking place in them. It can generate large fault currents that lead to a local temperature rise in the faulty stator slot, which deteriorates the working performance of the machine or even cascades to a complete machine breakdown. This article focuses on developing transient thermal models for an induction machine under ITSC faults. The aim of these thermal models is to understand the thermal behaviour of the induction machine at different ITSC fault propagation stages. The first thermal model is based on finite element method (FEM) simulation that includes a physics-based model for the thermal contact resistance. The second thermal model is a lumped parameter thermal network that models the stator as inter-connected slot-number parts. They are both capable of modelling the characteristic of non-uniform temperature along the circumferential direction for the induction machine operating under ITSC fault conditions. After area-weighted averaging the results of the FEM simulation, it is found they are quantitatively consistent, with an average relative error magnitude of 5%, as well.