Simulation of Induced Current in Water-blocking Buffer Layer of Corrugated Aluminum Sheathed Cable

The ablation problem of water-blocking buffer layer is a common fault in the operation of high voltage power cables with corrugated aluminum sheath in recent years, and the cause and mechanism are still not completely solved. Many studies point to the concentration of radial leakage current as a major cause, but the concentration of axial induced current has not been studied. In this paper, 3D simulation model of corrugated aluminum sheathed cable was established, and the distribution of induced current density in buffer layer was calculated based on finite element method. The results showed that at the contact point between the buffer layer and the corrugated aluminum sheath, part of the induced current on the buffer layer flowed into the aluminum sheath and then flowed back to the buffer layer. At the junction of buffer layer, aluminum sheath and air gap, the induced current on the buffer layer was concentrated. However, the induced current on the buffer layer was small and the concentration degree was limited. Compared with the leakage current density, the maximum induced current density was still small, and its influence can be ignored. The simulation results verified that the induced current on the buffer layer was concentrated at the contact point of the aluminum sheath, but it was not the main reason of ablation failure. This has certain reference significance for analyzing ablation cause and mechanism.