Thermal Dissipation Analysis of Submarine High-Voltage Cables in Saturated Soil Considering Thermo-Osmotic Effect

With the rapid development of offshore energy, high-voltage submarine cables have become crucial components for power transmission, enabling the large-scale integration of offshore energy. Current research on the safety of submarine power cables mainly focuses on coupled electro-thermal-hydraulic modeling of the cable-seabed system to predict operating temperatures, taking into account heat dissipation within the seabed. However, few studies have addressed the thermo-osmotic effects resulting from temperature gradients induced by heated buried cables. In this study, a fully coupled electro-thermal-hydraulic model incorporating the thermo-osmotic effect is developed by integrating the saturated soil seepage equation with the energy conservation equation. The accuracy of the proposed model is verified through comparison with simulation results from the model established by Hughes. Furthermore, this study analyzes the influence of soil permeability and thermo-osmotic coefficient on thermal convection, and investigates the variation patterns of the maximum cable temperature and excess pore pressure around the cable under various conditions. The results indicate that whether in high-permeability or low-permeability seabed soils, the thermo-osmotic effect has no significant impact on the maximum cable temperature. When the permeability is constant, an increase in the thermo-osmotic coefficient leads to a decrease in the excess pore water pressure around the cable. Conversely, when the thermo-osmotic coefficient remains constant, higher permeability will increase it. The research results provide important references and practical guidance for the design and installation of submarine cable systems.