With the development of underwater cable technology, These are widely used today for intercontinental communications, The interconnection of the islands, Offshore oil and gas platforms, offshore wind energy and other areas.
Types of underwater cables
Submarine cables are very varied and can be classified into four categories :
1.Number of drivers
Submarine cables are mainly divided into three-wire submarine cables and submarine cables to a wire. Low and medium-voltage lines mainly use three-wire submarine cables, While high-voltage lines mainly use submarine cables in a wire.
Structure of a unipolar submarine cable
Structure of a three-wire submarine cable
2.Transfer function
The function can be divided into two categories : underwater communication cables and underwater energy cables. Submarine communication cables are mainly used for communication services, such as the transmission of information such as voice, Data or images. Underwater communications cables are expensive but provide a high degree of privacy. One kilometer of submarine fiber optic cable will cost approximately 16520400 euros and could reach 190 620 000 euros.
The submarine electric cable is generally composed of a central copper or aluminum thread, insulation and sheath. The submarine cable is mainly used for high-power underwater underwater transmission, and the role of underground electric cables, but the application of the occasion and the installation of the different ways. The installation distance of underwater electric cables is much shorter than that of communication cables. The submarine cables are mainly used to connect land islands between them. They are also used to cross rivers or ports and to link platforms from Earth. They are also used to connect the platforms between them, etc.
Traditional submarine cables have only a pure electrical energy transmission function, The new submarine cable belongs to the photoelectric composite cable, effectively carrying out the transmission of electrical energy and signals on the same cable.
Optoelectronic composite submarine cable with three conductors
3.Transmission distance
Cables at the bottom of the sea can be divided into two types : offshore cables and ocean cables. Offshore cables generally refer to cables buried in seabed, their transmission distance is relatively short and the general requirements relating to the application environment are also relatively flexible. Ocean cables, as for them, are transoceanic cables connecting two or more countries or regions. They have longer transmission distances and must take into account complex factors such as topography of the seabed and the climate environment.
4.Type de charge
The submarine cables are classified as DC submarine cables and alternating current underwater cables.
The high-voltage and DC submarine cable is a high-voltage cable used for direct current energy transmission. It has the advantage of having a low loss of power, to facilitate the transmission of energy over long distances and to allow a large-scale energy exchange between submarines. However, The current experience in applying submarine cables to DC is not very rich and the construction costs of the DC conversion stations are high.
An alternative current submarine cable is a cable used for the transmission of alternating current. The transmission of electrical energy being affected by the inductive nature of the alternating current, Loss of electrical energy is significant when alternative underwater cables are used to transmit electrical energy. Compared to continuous underwater cables, The transmission distance is short, But the operating and maintenance technology of alternating current submarine cables is mature, construction costs are low and the cost is relatively low.
The design of underwater cables generally involves technical and economic compromises in order to maximize the advantages. Selecting submarine cables must also be based on specific uses and environmental requirements.
Underwater cable structures
So far, the structural design of the submarine cable has been the subject of various attempts. The submarine cable current mainly includes the following types :
1.Cable wrapped in impregnated paper. Applicable to lines not exceeding 45kV alternating current and 400kV direct current. Currently, it can only be installed at a water depth of 500 m or less.
2.Oil-filled cables. Eliminate air gap in cable using impregnant filling method. When the cable temperature increases, the impregnant expands, the internal pressure of the cable increases and the impregnant flows into the oil supply tank ; when the cable cools, the impregnant retracts, the internal pressure of the cable decreases and the impregnant from the oil supply tank flows into the cable, thus preventing the formation of air gaps, which allows it to be used for lines of 110 kV and more. Installation in a water depth of up to 500 m.
3.Inflatable cables (pressure assisted). The use of impregnated paper packets for inflatable cables is more suitable for longer submarine cable networks than oil-filled cables, but due to the need to operate in deep water using high air pressure, which increases the design of the cable and its accessories, generally limited to a depth of water 300 m or less.
4.Pipeline “hydraulic”. They are only suitable for cable systems of several kilometers, Due to mechanical constraints linked to very long cable print in the pipe.
5.Extruded insulation cables (Insulation in reticulated polyethylene, Ethylene-Propylene rubber insulation). Suitable for alternative tensions up to 200 kV. Ethylene-propylene rubber is more resistant to dendritic phenomena and localized power leaks than polyethylene, which allows underwater cables to operate more effectively.
The submarine cable is an essential channel for the transmission of energy. With the development of transmarine energy transmission, communications, Offshore oil and gas fields and other maritime projects, especially offshore wind energy and other new marine energies, the number of new underwater cables placed in the ocean increases, underwater cable design requirements, manufacturing and construction technology is also constantly improving. In the future, submarine cables will certainly experience greater development.
ZMS submarine cables have excellent resistance to water and corrosion. ZMS produces very reliable submarine cables with excellent transmission performance. They can operate stable in the underwater environment for a long period. They provide reliable support for underwater communications and energy transmission. If you have any questions about cables, Do not hesitate to visit our website or to contact us By e-mail at info@zmsoble.fr.