EoW September 2010

Fibre optic – machinery & equipment

Tubular bullhead strander for OPGW cables An optical ground wire (OPGW) is used in the construction of electric power transmission and distribution lines. Such cable combines the functions of grounding and communications. A typical OPGW cable contains a tubular structure containing one or more optical fibres, surrounded by one or more layers of steel and aluminium wires. Manufacturing of the aluminium central tube with the optical fibres inside • Stranding of the layer or layers of steel/aluminium wires over the central tube • The first process is the most critical and technological, but the second process also has huge influence on the quality and cost of the final product. Typically the application of the wires over the central tube is made with a planetary strander which, although producing a high quality product, has a low production speed and long bobbin reloading time. The manufacturing of this cable is divided in two processes:

Tubular bullhead strander for OPGW ▲ ▲

An alternative to the planetary strander is a tubular strander, which has a much higher stranding speed. The drawback of the tubular strander is that the centre core has to pass through the periphery of the long tube; its rotation can create twists and friction and, finally, damage the aluminium tube with the optical fibres inside. Caballé believes it has solved the drawbacks of both machines by adding a bullhead feeder at the end of the tubular strander. The feeder consists of a large payoff with bows that turn around it and convey the wires coming from the tube to the closing point. Features of this bullhead tubular strander include: Handles 12 – 24 steel/aluminium wires • 1,600mm – 2,500mm central tube reel size • Special wire path for aluminium coated steel wires (ACS) • Tension control by motor/dancer system • 500rpm maximum stranding speed • With this system the central aluminium tube payoff is completely straight with no added twist; the quality is the same as with a planetary strander but with a much higher stranding speed. The productivity of this machine is said to be five times higher than a planetary strander and the machine is already in use with several OPGW cable manufacturers. CM Caballé SA – Spain Fax : +34 93 399 0008

Email : caballe@cmcaballe.es Website : www.cmcaballe.es

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EuroWire – September 2010