Configuration and Model Order Selection of Frequency-Dependent π Models for Representing DC Cables in Small-Signal Eigenvalue Analysis of HVDC Transmission Systems

Eigenvalue-based analysis of small-signal dynamics in high-voltage direct current (HVdc) transmission systems requires cable models that are compatible with a state-space representation. While distributed parameter accounting for frequency-dependent effects inherently incompatible representation, conventional π model can only represent the behavior accurately at single frequency. Instead, (FD- π) consisting lumped circuit representation multiple parallel RL branches each π-section be utilized to reproduce frequency dependence characteristics specified range. Based on an evaluation relevant error metrics FD- models, this article demonstrates how number sections and section will influence accuracy. From starting point, optimization algorithm identifying configuration fulfills set accuracy requirements lowest possible order is introduced. A similar most accurate within maximum also proposed. Examples numerical results different lengths cross presented highlight their effect model, it demonstrated from eigenvalue HVdc systems.