Branch companion modeling for diverse simulation of electromagnetic and electromechanical transients

Simulators of the Electromagnetic Transients Program (EMTP) type are widely used for the study of high-frequency transients in power electric systems. For the study of electromechanical transients, where the main interest is to focus only on deviations from the ac waveform, the EMTP approach is not efficient. In this paper, a branch companion model that is suitable for both electromagnetic and electromechanical transients simulation is proposed. It processes analytic signals whose Fourier spectrum can be shifted in accordance with the objective of the study. The proposed method opens the way for a unified description of electromagnetic and electromechanical transients simulation.