Magnetically-Saturable Voltage-Behind-Reactance Synchronous Machine Model for EMTP-Type Solution

A so-called voltage-behind-reactance (VBR) machine model has recently been proposed for the electro-magnetic transient programs (EMTP) as an advantageous alternative to the conventional
qd
and phase-domain models. This paper extends the previous research and proposes a magnetically saturable VBR synchronous machine model for EMTP-type solutions. The proposed saturable VBR model utilizes the saliency factor approach to represent main-flux saturation for the salient-pole synchronous machines with the
qd
axes static and dynamic cross saturation included. An efficient piecewise-linear method is used for representing the nonlinear saturation characteristic within the discretized EMTP solution. Case studies verify that the new model maintains the improved numerical accuracy in steady state and transients even with large time step.