Influence of Soil Thermal Resistivity and Ambient Temperature on the Ampacity of Submarine Cables

This paper presents an analysis of the allowable current of submarine power cables, considering the specific characteristics of their actual installation environments. As the expansion of offshore wind farms and submarine transmission networks accelerate globally, the demand for reliable submarine cables has surged. However, due to the absence of design standards for submarine cables, their ampacity is calculated by applying standard for underground cables. These traditional methods fail to reflect unique seabed conditions, such as soil thermal resistivity and ambient temperature.<br/>In this study, finite element method (FEM) analysis was performed on an AC 154kV XLPE 3-core 500mm² submarine cable to evaluate how these environmental parameters influence the cable's thermal behavior and ampacity. The reliability of the numerical model was validated by comparing the results with analytical calculations based on the international standard, IEC 60287. The results reveal that environmental factors significantly affect ampacity estimation, with soil thermal resistivity showing a more pronounced influence than ambient temperature. Specifically, under buried installation conditions, it was confirmed that soil thermal resistivity acts as the more dominant governing factor in determining submarine cable ampacity. These results suggest that incorporating site-specific environmental data is essential for optimizing submarine cable design and ensuring operational reliability.