Technical comparison among different solutions for overhead power transmission lines

The goal of this paper is to develop a technical comparison among different possible solutions for overhead transmission lines. These include both traditional and inno-vative solutions: the former are usual three-phase AC lines and HVDC lines, the latter are four-phase AC lines and combined AC-DC lines. A technical-economical comparison between aerial standard three-phase AC and innovative four-phase AC lines has been already developed in [1], where the possible scope of convenience of the four-phase solution has been individuated. This paper first illustrates the main characteristics of the four considered solutions, pointing out the technical advantages provided by each one. Secondly, the paper performs a more detailed comparison based on a probabilistic analysis of the transient stability performances of the considered alternatives