Investigation on the Ampacity of AC Submarine Cables in J-Type Conduit Trenchless Installation

For the installation of submarine cables at sites with significant elevation differences and non-excavation bases, the J-type conduit represents an emerging installation solution. This study focused on a typical AC submarine cable installed via J-type conduit trenchless installation. A coupled electromagnetic–thermal–fluid finite element model was established to investigate the effect of the burial depth, conduit material, and environmental temperature on the ampacity of the cable. The results indicate that the ampacity of the cable decreases as the burial depth increases due to the deteriorating heat dissipation capacity of the soil. Regarding the internal medium of the conduit, the cable demonstrates superior ampacity performance in muddy water. Additionally, J-type conduits fabricated from non-magnetic metallic materials such as copper and stainless steel exhibit significantly higher cable ampacity compared to polymeric materials like PE and PVC. As the soil’s temperature rises with the increasing environment temperature, its thermal conductivity efficiency decreases, consequently impairing cable heat dissipation and ampacity.