Frequency-Domain Simulation of Electromagnetic Transients Using Variable Sampling Time-Step

This letter presents the extension of a previously proposed frequency-domain (FD) approach for the analysis of electromagnetic transients (EMTs), primarily due to a set of discrete switching events, in an electric power network. The method is based on dividing the analysis time window into a set of subwindows with equal or unequal time lengths and solving each in the FD. The sampling time step is also independently selected for each subwindow. The extended method, formerly proposed for a single transmission line, can readily use the concept of network equivalents, achieving efficient EMT solutions of large systems, and can simultaneously accommodate slow and fast dynamics.