Analytical calculation model for stator winding faults in synchronous machines

The calculation of currents and torques after inner faults in the stator of synchronous machines requires accurate models considering the inner asymmetry of the winding. The paper introduces a mathematical network model of a synchronous machine with arbitrary short circuited windings, which is generally open for the consideration of nonlinear iron. The system of equations is derived using an example case of a phase-to-phase fault, for which results are presented and compared to transient FEM calculations. Afterwards the influence of iron saturation is investigated and the extension of the model with current dependency of the inductivities is discussed.