Application of Levinson algorithm for fault calculations in high phase order transmission systems

Abstract

Ever increasing pressures against the construction of new high voltage transmission lines are forcing electric utilities to seek new ways of augmenting the power transmission capabilities of existing rights-of-way. One of the alternatives being contemplated is high phase order transmission, where the number of phases is raised from three to six, twelve or higher. In order to make full utilization of the idea, transmission line design with the phase conductors being located on the circumference of a circle is advocated. The primitive impedance matrix of such a configuration of phase conductors is a Toeplitz matrix and is also symmetric. A generalized approach based on the application of Levinson algorithm is developed in the present paper for the calculation of fault currents in an arbitrary N-phase transmission line. The fault currents due to faults involving any number of phases to ground are calculated using the algorithm. Results for six and twelve phase systems obtained using the method are included in the paper.