A Z-matrix building algorithm for unbalanced power systems with mutually coupled lines

A generalized personal-computer-based algorithm is described for constructing the three-phase bus impedance matrix from transmission line data and load/generator impedances. The algorithm incorporates optimal line ordering and shunt elements in the network. In addition to these features, the algorithm accounts for direct and indirect mutual coupling of three-phase lines. The algorithm is unique in that the primitive impedance matrix necessary to process a mutually coupled line is computed when the line is processed