Y-Parameters Model of Cross-Bonded Cables Including Bonding Wire Impedances

Abstract

Cables with cross-bonded cable sheaths are predominantly used in high-voltage ac systems. Existing frequency-domain models of such cables use ABCD-parameters, which may cause numerical problems in the high-frequency region, or Y-parameters. The existing Y-parameters model excludes bonding wire impedances which may result in inaccurate estimates of the magnitude or frequency of the cable input impedance at resonant frequencies. This letter extends the formulation of an existing Y-parameters model to include bonding wire impedances. The proposed extended formulation is validated against a cable model in commercially available EMT-type software, in frequency- and time domain. For a certain bonding wire impedance model, the proposed Y-parameters model is shown to have a lower magnitude of the cable input impedance at resonant frequencies compared with a model excluding bonding wire and grounding impedances.