Abstract:　 A tri-axial HTS cable which is composed of three concentric phases is more advantageous than a triad coaxial cable composed of 3 separate centers， because of their reduced amount of HTS tapes， low leakage fields， low heat leak and compactness. We analyzed the balanced three phase current distributions in the tri-axial cable as functions of winding pitches of three concentric phase layers. On the basis of the analysis， we study the minimum voltage drop in various tri-axial cables to improve power stability. Therefore， we surveyed the fabrication parameters of a tri-axial cable， in terms of twisting pitch and segment lengths of any actual cable. We find minimum values of voltage drops for various given configurations. To achieve optimum cable construction parameters we think of different cable designs in terms of minimum voltage drop considerations.