Reduced order transmission line models for power system analysis

This article presents a technique to compute reduced order models of transmission lines which are amenable to embedding in eigenvalue analysis and simulation programs for linear continuous time-invariant power system representations. In the first step, a lumped approximated model of each transmission line is computed, then in the second step a model-order reduction technique is applied on subsystems of transmission lines by means of balancing and truncation. The technique is superior to modal truncation as the system matrices remain real and system zeroes can be matched. It is also superior to pi-section modelling in terms of transfer function approximation at the same model order. Examples are shown to illustrate the advantages of the technique over conventional representations.