Optimal EMT Simulation Time Step Selection Based on Small-Signal Analysis

This paper presents a new methodology to define the optimal simulation time step of Electromagnetic transient (EMT) simulations of modern power system dynamics. Such networks introduce much faster dynamics, given the harmonics and control system generated by power electronics. A common approach to simulate those systems is to define the simulation time step by trial and error or to select based on experience from other projects. Such approaches can result in time steps that are either too large to capture the fastest dynamics accurately or too small, leading to unnecessarily long simulation times. Therefore, this paper proposes a method that uses small-signal analysis to calculate the system’s fastest time constants and define the optimal time step based on those time constants. This approach ensures an accurate representation of all relevant phenomena while minimizing computational effort. The method was tested on a modified version of the IEEE 118 bus system, and the results confirm its applicability in finding optimal time steps.