Research on Electromagnetic Loss Characteristics of Submarine Cables

The electromagnetic losses of submarine cables are mainly caused by the metal shielding layer to prevent the water tree effect and the armor layer that strengthens the strength of the submarine cables. While these losses cause the temperature of submarine cable to rise, and temperature variation will in turn change the conductivity of its metal layer material. In this paper, the electric-magnetic-thermal multi-physical field coupling of the electromagnetic loss variation of the submarine cable is realized by establishing a full coupling system containing Fourier’s law and Maxwell-Ampère’s Law for the photoelectric composite submarine cable. The multi-physical field coupling model is solved and analyzed by using the finite element method. Firstly, the loss of each layer of the optoelectronic composite submarine cable is analyzed, and the loss of each layer of the submarine cable and the main factors leading to the loss of the submarine cable are given. Secondly, the influence of environmental temperature, ampacity and armor layer on the electromagnetic loss of submarine cables is studied, and the main operating factors affecting the electromagnetic loss of submarine cables are summarized. The research shows that the influence of ambient temperature can be ignored, and the loss of shielding layer and armor layer increases with the increase of ampacity, but the impact of shielding layer loss is greater. Finally, this paper studies the electromagnetic loss of each metal layer of the submarine cable and the influence of the laying spacing on the electromagnetic loss. The research results show that the two ways of improving the conductivity of the armor layer and reducing the relative permeability of the armor layer can effectively reduce the loss of each metal layer in the cable structure and increase the current carrying capacity when the tensile strength of the armor layer meets the requirements for single-core and three-core photoelectric composite submarine cables laid horizontally. At the same time, increasing the laying spacing will increase the loss, but it can improve the overall current carrying capacity of the cable. The research in this paper provides a theoretical basis for the design of submarine cable carrying capacity, and also provides a reference for the optimization design of submarine cable structures.