Modified magnetic-equivalent-circuit approach for various faults studying in saturable double-cage-induction machines

Modified magnetic-equivalent circuit for a double-cage-induction machine in both healthy and faulty cases is presented in this study while slot skewing, saturation effect and also space harmonics are considered. Moreover, in simulation, pole numbers, rotor bars and slot numbers are chosen arbitrarily and the behaviour of the saturable double-cage-induction machine is studied under various kinds of faults. Broken bar in both inner and outer cages and also inter-turn short circuit of stator windings are modelled and fault detection methods are presented. Differential equations are converted into algebraic equations using trapezoidal technique and are solved together with non-linear magnetic equations simultaneously. To reach this aim, at first, a single set of the system equations including magnetic and electric equations are generated, and then they are solved by the Newton–Raphson method in each time step. As an advantage of this study, the presented model is capable of modelling the healthy and faulty machine under various kinds of faults by a single model which has profound effect on reducing the complexity of equations and the simulation time. Finally, effectiveness of the proposed method is verified using finite-element method via Flux software.