The whole manufacturing process of submarine power cables is basically the same as that of ordinary power mobile cables, but the mechanical strength and anticorrosion requirements of the cables are special, and the cable length is required to be extended as far as possible. The manufacturing process of impregnated paper cable and extruded insulated cable is briefly described below. The impregnated paper cable is first wrapped with insulating paper, then dried in vacuum, soaked in oil, and then wrapped with lead. At this time, the cable must undergo continuous extrusion process. Extruding a very long cable core is a very important step and must be carried out day and night. The conductor core of the oil-filled cable passes through a siphon conveyor pipe from the cylinder to the lead presser. The degassing oil is injected into the pipe to flow in the reverse direction to the conductor core so as to isolate the contact between the conductor core and the air. After the lead sheath is wrapped in the conductor core, the wire should be coiled on the rotating platform (if the cable is oil-filled or inflatable, a suitable amount of metal reinforcement can be added), then the cable should be wrapped with polyethylene sheath (extruded polyethylene sheath is also a continuous operation), and then coated with two-layer galvanized steel wire armour, and the oil-linen impregnate compound. In the post production process, the lead sheath and metal strip must be grounded through the polyethylene sheath at the appropriate stage. In most production processes of XLPE cables and EPDM insulated submarine cables, besides the extrusion and vulcanization of synthetic rubber insulation layer, the manufacturing process of XLPE cables is similar to that of paper insulated lead-sheathed cables, but lead sheath is not used.

Performance indicators and test methods

Mainly electrical performance indicators and mechanical and physical performance indicators. These indexes and test methods are the same as those of underground power cables.

Electrical performance index: DC resistance and AC impedance of conductor; insulation resistance of insulating layer; dielectric loss of RG coaxial wire; current carrying capacity; capacitance and inductance of cable; induced voltage and current of metal shield.

Mechanical and physical properties: mechanical strength of cable; tensile strength and elongation of conductor; mechanical and physical properties of insulating layer material.

Inspection methods: The main standards recommended by the International Electrotechnical Commission are IEC 60502, IEC 540 and IEC 60141-1 to IEC 60141-4. Most of the cable manufacturers in the world have their own standards, such as JIS in Japan, BS in Britain and CSA in Canada.

Packaging and storage and transportation

Because the submarine cables want to be made longer to reduce joints, they can be produced on the coast. The packaging should be different from other cables. Generally, the marine cable is coiled on a storage tray or turret for shipment to the cable laying vessel, and the cable is transported to the laying area by the cable laying vessel. Cable laying boats are designed and built for laying cables. They must also be equipped with gantry cranes, stranding shafts, oil filling systems and other facilities, but other boats with special mechanical equipment for laying cables can also be used.

Matters needing attention

Submarine cables are products subject to the export quality licensing system. Manufacturing enterprises must obtain export quality licences issued by the State Entry-Exit Inspection and Quarantine Department in accordance with regulations before they can produce export products.

At present, there is no direct communication optical cable connection between the mainland of China and Taiwan Island, and the information is generally exchanged through the submarine optical fiber cable of the United States. At present, the global Internet is realized through the submarine optical fiber communication cable, and the submarine optical fiber cable system of the "Pacific Expressway" is being prepared, and the length will be as long as possible. To 2 5000 km, linking China, the United States, Japan, South Korea and many other Pacific countries.

The Atlantic Cable was successfully laid in 1866 and transatlantic telegraphic communications between the continents of Europe and the United States were realized. Today, with the development of social economy and technology, there are more and more kinds of submarine pipelines. According to the use, the submarine pipeline can be simply divided into oil pipeline, gas pipeline, water pipeline, etc. The submarine cable mainly includes communication optical cable, transmission cable, communication cable and so on.