In this paper, the authors deal with circuit representation of load and line asymmetries in three-phase power systems. Indeed, it is well known that under the assumption of symmetrical phases, power systems are effectively analyzed through the symmetrical component transformation leading to uncoupled sequence circuits. In practical power systems, however, the assumption of symmetrical phases is not always met for several reasons including, for example, single-phase loads (e.g., high-speed railway systems) and untransposed overhead transmission lines.