The idea of underwater telegraphic communication was suggested in 1795 by a Spaniard named Salva. But the first single wire cable was laid in 1850 between England and France. Unfortunately, this cable did not last very long. Subsequently, a heavier armored cable with four conductors was successfully laid. Over the years, due to advanced technology, long length cables have been laid between various continents to accomplish power transmission, data transmission and communication signals. These underwater cables require substantial protection due to severe installation conditions and exposure to corrosion. Armoring is one of the most important phases in the production of submarine cables to achieve required strength and corrosion protection. Armoring of these cables is performed on a planetary strander. A typical armoring line consists of a planetary strander, tangential (or eccentric) taping head, bitumen applicator, serving machines suitable for various types of yarns, wire pre-formers and other auxiliary equipment to control and handle the cable after armoring.
There are two main categories of submarine cables:
• Extremely long lengths for installations under ocean between continents. These cables require precision factory joints to achieve these lengths. These cables are used for medium or high voltage applications.
• Short length installations for small bodies of waters such as rivers and lakes, connecting off-shore platforms and ocean installed wind farms. These cables in most cases do not exceed depths of more than 200 meters.
Production of very long lengths cables required for trans-oceanic installations demands a large capital investment and high level of skills. The short length submarine cables have relatively low capital investment. These short lengths do not require any factory joints. In some cases, it is also possible to upgrade an existing planetary cabler to armor short lengths of cables.
Armoring of submarine cables is done on a planetary strander using round or flat wires made of galvanized steel, stainless steel, aluminum alloy or copper. The diameter of the round wire is 3-7mm and the flat wire is 5mm x 13mm maximum. Depending upon the length of submarine cable that needs to be armored, the planetary strander can have one or two cages. A typical configuration of a planetary strander can be as follows:
• For smaller sections of Medium Voltage submarine cables and for single-core High Voltage cables, a 56 cage planetary strander is sufficient
• For bigger sections of Medium Voltage and 3-core High Voltage cables, the number of cradles could be up to 110
• Typically 800mm payoff reels are sufficient to armor short length cables.
OM Lesmo Group offers several years of experience in armoring of submarine cables. A complete line is available for up to 110 cradles per cage, taping heads, capstan, take-up and all other required auxiliary components for the production of armored submarine cables. The 800mm pay-off reels have a capacity of 1100kgs gross weight. Lay lengths of more than 3000mm can be produced on such machines. Cable diameters of up to 400mm can be armored.
OM Lesmo 630mm Planetary Strander, in conclusion, in the modern world, the communication gap is getting narrower and narrower. One of the links to accomplish this is the armored submarine cable. The armoring process not only provides the strength needed for installations in severe conditions but also provides the protection against corrosion while the cable is laying under water for years and years.