SVD-based reduced-order rational approximation for EMT analysis

This paper introduces a simple and effective model order reduction approach based on singular value decomposition (SVD) and aimed to electromagnetic transient (EMT) analysis. The proposed approach initially adopts a rational approximation obtained by the vector fitting (VF) software tool for an arbitrary frequency range. Then, it applies SVD-based truncation separately to low-frequency range and to the error given by the original function and the low-frequency approximation in the high-frequency range. Finally, the resultant reduced approximations are assembled for EMT solution allowing the use of two different time-steps. The obtained reduced-order model achieves computational savings compared to the original full-size system given by VF. A case study is presented to validate the proposed method.