Study on Sheath Circulating Current of Cross-linked Power Cables

The inductive voltage and the current flowing in the metallic sheath of power cables play important roles in the service of power cables, especially influencing their current capacities and reliabilities. In this paper, for the widely used cross-linked grounding cables, a model for calculating the current flowing in the metallic sheath of cable, including inductive current which is calculated by an iterative method and capacitive current which is calculated by a differential method, is presented. And this process is proved out by the comparison between the calculating results based on the parameters of the cable and the measuring ones. In addition, there is also an analysis of the relationship between the calculating results and some factors including the separation of the cables, the distance between the cables and the resistance of the nodes. The presented calculation method has been used in a software which is adopted by a regional Electrical Power company, and it is proved to be helpful to the management of power cables by judging whether the current flowing in the metallic sheath is acceptable.