Approximate Voltage-Behind-Reactance Induction Machine Model for Efficient Interface With EMTP Network Solution

A so-called voltage-behind-reactance (VBR) induction machine model has recently been proposed for the Electro-Magnetic Transient Program (EMTP) solution as an advantageous alternative to the traditional qd and phase-domain (PD) models. This paper focuses on achieving an efficient interface of the machine models with the EMTP network. It is shown first that a discretized PD model can be formulated to have a constant machine conductance submatrix, which is a very desirable numerical property that allows avoiding the re-factorization of the network conductance matrix at every time step. Furthermore, an approximate voltage-behind-reactance (AVBR) model is proposed where the rotor-speed-dependent coefficients are neglected, thus leading to a similar constant machine conductance submatrix and efficient interface. Case studies demonstrate that the new AVBR model represents a significant improvement in terms of numerical accuracy and efficiency over other established models used in EMTP.