Multirate EMTP-Type Induction Machine Models

Recent focus on component-network interfacing has greatly increased the maximum step size at which machine models can be simulated accurately and stably in nodal-analysis-based electromagnetic transients programs (EMTP-type). However, considerably smaller step sizes are often used in practice due to the presence of fast modes in external power networks. To further improve simulation speed, this paper proposes a multirate framework for EMTP-type machine models connected to dynamically faster power systems. In particular, two multirate induction machine models based on the voltage-behind-reactance (VBR) formulation are presented. These new models can be interfaced directly with commercial EMTP-type programs with no modifications to their computational engines. The presented computer studies demonstrate the superior combination of numerical accuracy and efficiency of the proposed multirate models compared with the existing models.