Assessment of Different Frequency-Dependent Line Models for EMT Simulations of HVDC Systems

This paper presents a comprehensive as-sessment of four transmission line models available in the Alternative Transients Program (ATP)/ATPDraw: Bergeron, classic J. Martí, vector-fitting-enhanced J. Martí and the Universal Line Model (ULM), focusing on the Madeira River HVDC ± 600 kV bipole in Brazil. A benchmark model, based on rigorous earth formulations and transients computations using the numerical Laplace transform (NLT), allows for detailed analysis across various frequencies. Key findings include the inadequacy of Bergeron model beyond the fundamental frequency, superior accuracy of ULM over a wide spec-trum range, and acceptable accuracy of both J. Martí approaches at higher frequencies. Notably, the J. Martí model requires careful evaluation of frequencies near DC.