Including Magnetic Saturation in Voltage-Behind-Reactance Induction Machine Model for EMTP-Type Solution

A voltage-behind-reactance (VBR) machine model has been recently proposed for the electro-magnetic transient programs (EMTP)-type simulation programs. The VBR model greatly improves numerical accuracy and efficiency compared with the traditional qd and phase-domain (PD) models. This paper extends the previous research and presents an approach to include magnetic saturation into the VBR induction machine model. The presented method takes into account the qd axes static and dynamic cross saturation, whereas the nonlinear magnetic characteristic is represented using a piecewise-linear method that is suitable for the EMTP solution approach. Case studies verify the new saturable VBR model and show that it has improved numerical stability and accuracy even at large time steps.