Patent ID: 7976747

Claim:
A method for extending the useful life of at least one in-service electrical cable section having a stranded conductor surrounded by a conductor shield encased in a polymeric insulation jacket and having an interstitial void volume in the region of the conductor, the cable section having an average conductor temperature T, the method comprising: (i) continuously introducing a non-condensing exclusion fluid into the interstitial volume, said exclusion fluid comprising at least one non-condensing exclusion component having a solubility in the insulation polymer at least 100 times the corresponding solubility of water, each solubility being determined at temperature T; and (ii) injecting a condensing dielectric enhancement fluid into the interstitial void volume to displace the exclusion fluis previously introduced, wherein said dielectric enhancement fluid has a virtual flow rate within said interstitial void volume of less than about 0.1 liter per hour.