Cables and overhead lines are key components in electric power systems, with conductors belonging to those components being electromagnetically coupled. Time-domain analysis of steady-state and transient regimes in cables and power lines usually requires the use of frequency-domain modal analysis techniques where mode decoupling is achieved by solving an eigenvalue–eigenvector matrix problem. In this article, an alternative method is developed for the
modal analysis of n-coupled multi-conductor transmission lines employing
a simple intuitive approach. The method provides a speedy solution of the eigenvalue–eigenvector problem based on an initial
guess for the modal transformation matrix; the accuracy of the method
can be controlled and improved easily by iterating the proposed algorithm
a few times. The method is exemplified with vertical and
triangular single-circuit three-phase transmission lines choosing the Clarke matrix as the initial approximation for the modal transformation