Variable Time-Step For Power Grids Emt Simulations

This paper presents a new variable time-step method for the electromagnetic transient (EMT) simulation of power systems. Trapezoidal discretization with a constant time-step is commonly employed in EMT simulations of power systems. During an EMT simulation, power systems typically encounter high-frequency transients that demand small time-steps for accuracy, as well as low-frequency and steady-state conditions that allow larger time-steps for efficiency. With a fixed time-step, either the simulation accuracy or speed is compromised, and achieving a trade-off is not feasible for all cases. Consequently, this paper proposes a novel variable time-step strategy for maintaining both simulation accuracy and speed. The performance of the proposed method is verified through the WECC 240-bus system.