Adequacy of Time-Domain Line Modeling for Power Electronics Studies

This paper evaluates four distinct implementations of transmission line models in a power electronics application: Nominal Pi-Section, Bergeron, ULM Vector Fitting Based, and ULM Frequency-Partitioning Fitting Based. A brief theoretical review of these implementations is presented. The power electronics application to compare these models consists of a current source, representing a power injection in a DC link, a three-phase inverter, and a transmission line feeding a resistive load. The paper shows results for both overhead lines and underground cables scenarios. The four line models are simulated in EMT programs and have their harmonic propagation compared, as well as their Total Harmonic Distortion (THD). The results show that the choice of a transmission line model is a determining factor to analyze harmonic propagation in power systems and it may impact directly the design cost of several projects.