Improving Accuracy of Interpolation Algorithm in EMT Simulation: A Padé Approximation and Switching Theorem Based Approach

As renewable sources and power electronic devices become more prevalent in the power system, the characteristics of power system are now shaped by power electronics, which presents new challenges for the acceleration algorithm used in electromagnetic transient (EMT) simulation. In this context, this paper refines five key technical points of interpolation algorithms and proposes an improved interpolation algorithm. In particular, the Padé approximation is adopted and combined with numerical integration methods to establish a discrete model for accuracy and stability improvement. The switching theorem is used for re-initialization, which further reduces the switching error and reflects more realistic switching transients. Moreover, the algorithm's stability is theoretically proved through Lyapunov stability analysis. With the improved interpolation algorithm, switching transients can be accurately simulated while maintaining high simulation efficiency and stability. The performance of the proposed method is validated by both simulation and experimental tests.