Submarine cable classification and use

Submarine cables are wires covered with insulating materials laid under the sea and rivers for telecommunication transmission. Modern submarine cables use optical fiber as a material to transmit telephone and Internet signals.

Submarine cables are divided into submarine communications cables and submarine power cables. Submarine communications cables are mainly used for communications services and are expensive, but have a high degree of confidentiality. The submarine power cable is mainly used for underwater transmission of high-power electric energy, and is equivalent to the underground power cable, except that the application occasions and laying methods are different.

Submarine cable classification

Impregnated paper package cable: Suitable for lines of not more than 45kV alternating current and not more than 400kV direct current. Currently it is only installed in waters with a water depth of less than 500m.

Self-contained oil-filled cable: Suitable for DC or AC lines up to 750kV. Because the cable is oil-filled, it can be laid without difficulty in waters up to 500m deep.

Squeeze Insulation (Crosslinked Polyethylene Insulated, Ethylene Propylene Rubber Insulated) Cables: Suitable for up to 200kV AC voltage. Ethylene-propylene rubber is more effective than polyethylene in preventing branching and local leakage, allowing the submarine cable to function more effectively.

"Hydraulic" pipe cable: only for cable systems of several kilometers in length, because very long cables are pulled into the pipe, subject to very large mechanical restrictions.

Inflatable (pressure-assisted) cables: Inflatable cables using impregnated paper bags are more suitable for longer submarine cable networks than oil-filled cables, but due to the need to operate at high pressures in deep water, the design of cables and their accessories is increased. The difficulties are generally limited to water depths of less than 300m.

Submarine cable use

Submarine communication cables are mainly used in long-distance communication networks, and are often used in more important occasions such as between long-distance islands and cross-border facilities. The laying of submarine power cables is much shorter than that of telecommunication cables. It is mainly used to connect land-based islands, across rivers and harbors, and to connect land platforms or drilling platforms.