On the use of Polyethylene Insulation in the Manufacture of Submarine Cables

In the manufacturing process of a submarine coaxial cable, a multitrough water cooling system is used to avoid formation of voids and to strengthen the gripping force between the insulation polyethylene and the metallic center conductor. In submarine coaxial cable systems, the standards for dielectric properties of the insulation, polyethylene, are very strict. The adverse effect of small amounts of water in the polyethylene can not be neglected. In the cable manufacturing process quench cooling is favorable to the decrease of the water content in polyethylene. On the other hand, gradual cooling is better to avoid formation of voids. To find the optimum manufacturing process under these two conflicting conditions, computor simulations of the diffusion mechanism of water in polyethylene and the void forming mechanism have been made using available experimental data.