Wave Propagation in a DC Superconducting Cable Part I: Analysis

We consider a dc superconducting cable design consisting of four concentric metallic cylinders, of which two carry the load current and two comprise the cryogenic enclosure. When a transient voltage is impressed across such a cable, the major dielectric may not be fully stressed to its design value, and unwanted voltage stresses may develop across other parts of the cable. This paper analyzes the surge-voltage propagation characteristics of a four-conductor dc superconducting cable for a step-function input voltage. This analysis, although mainly directed to superconducting cables, is also applicable to other-multiconductor tranmission lines. A companion paper discusses the parametric effects of the cable system in optimizing the voltage distribution.