Impact of rheological properties on conductor shield convolutions in power cables from a continuous vulcanization process

The smoothness of the interface between the insulation layer and the semiconductive conductor shields is very important to provide a uniform electrical stress gradient preserving the long term electrical performance of power cables. Any convolutions or protrusions from the semiconductive conductor shield into the insulation layer can result in localized electrical stress and induce undesired treeing or electrical degradation. An investigation of the compound melt rheology and its relationship to conductor shield convolution will be described. It will be shown that the inherent rheological properties of the semiconductive conductor shield compound in combination with the fabrication conditions in the continuous vulcanization of power cable manufacturing process determine the tendency for convolutions to develop