Theoretical transmission-line study of symmetrical indoor triple-pole cables for single-phase HF signalling

Theoretical study of symmetrical single-phase indoor tricels is performed with respect to high-frequency (HF) transmission-line modeling, aimed at potential communication applications over the low-voltage (LV) in-house grid. The analysis is based on the fundamental transverse-electro-magnetic (TEM) wave propagation concept, commencing from the three-conductor transmission-line model. In the three-wire cable, any transmission circuit consisting of two conductors-out of all three-is by virtue of symmetry reduced to a two-conductor formulation. The distributed parameters of the resulting model are moreover extracted via proper observation of cable´s field structure, where complete conformance with the uniform isolated two-conductor line is obtained. Propagation of high frequency signalling transmitted between phase and neutral may thence in practice be treated and formulated independently, as if no ground wire existed. In addition, verification of the TEM mode assumption is demonstrated, and hints on the applicability of the work presented are suggested.