Patent ID: 8205326

Claim:
A method for enhancing the dielectric properties of an electrical cable segment having a central stranded conductor surrounded by a conductor shield and encased in a polymeric insulation jacket and having an interstitial void volume in the region of the conductor, said method comprising: (a) filling said interstitial void volume with a weight W s of a fluid dielectric property-enhancing composition at a pressure P, said pressure being below the elastic limit of said polymeric insulation jacket and imposed along the entire length of said segment; and (b) confining said composition within said interstitial void volume at essentially said pressure P, with the proviso that, (i) when (W s −W i )>0, P is adjusted such that W s =W i ; and (ii) when (W s −W i )<0, a weight W of a second dielectric property-enhancing fluid is added to said composition of step (a) such that (W+W s )=W i , said second dielectric property-enhancing fluid having a permeability property of less than 10 −10 g/second-cm at 25° C. and having at least one property selected from the group consisting of: (I) a diffusion coefficient of less than 10 −8 cm 2 /second at 50° C. and (II) a solubility of 0.0001 to 0.02 grams/cm 3 at 25° C., wherein each property is measured in said polymeric insulation jacket, W s is the weight of said composition required to saturate said conductor shield and said insulation jacket of said cable segment, and W i is the weight of said composition which can be injected into said interstitial void volume at pressure P.