Influence of multi-layered sediment characteristics on the thermal performance of buried submarine high-voltage cables.

The safe and efficient operation of submarine high-voltage cables depends on their thermal performance. Based on the electromagnetic heat coupling and heat transfer theory, the cables' heat dissipation in multi-layered sediments is simulated using FEM. The proposed models are validated by comparing with the results of IEC 60287 and illustrated the limitation of IEC 60287 which ignores convective heat transfer. Further, the width of the cable embedding layers greater than 9 m can promote heat dissipation when the permeability of the cable embedding layer is relatively high, but the effect of depth is less pronounced. Also, the cable temperatures increase with the decrease of sediments thermal conductivity and increase of the buried depth when permeability is below 10−12 m2. The temperature decreases as the permeability increases, the range of decay is between 10% and 55% when the permeability reaches 10−9 m2. The heat dissipation is great when the permeability is greater than 10−11 m2. When the characteristic of the cable embedding layers is different from its upper and lower layers, the high permeability of the upper layers reduces the cable conductor temperature more efficiently than the lower layers. The findings give some reference in improving the transmission efficiency of cables. • The influence of multi-layered sediment characteristics on the thermal performance of submarine cables is analyzed. • The high permeability could help dissipate heat efficiently, the decay of conductor temperature can be up to 40%. • This paper illustrated the limitation of present methods in IEC 60287 which ignores the effect of convective heat transfer. • The submarine cables buried in sands or coarser sediments are better, and the buried depth is as small as possible. • The width of the cable embedding layers greater than 9 m can effectively promote the convective heat dissipation. [ABSTRACT FROM AUTHOR]