EuroWire May 2020

Technology News

Polypropylene power insulation

RoSET is the name of Rosendahl’s next-generation power cable insulation technology for MV cable production with polypropylene-based compounds. A number of cable makers, along with major utilities worldwide, are already producing and testing polypropylene- based insulation systems (PPC) for MV and HV applications, both in AC and DC. PPC systems are characterised by a lower carbon footprint, no need for degassing and no by-products, as well as being recyclable, and having equal or better electrical properties and higher operating temperature. The cables can also be installed in an XLPE-based network using the same accessories as XLPE cables. Rosendahl conducted both internal and test institute tests, which revealed the electrical performance at both the AC breakdown and impulse tests. The successfully passed full electrical type test also showed low loss factor (tan delta) values, even when compared to the reference peroxide XLPE grade. The new RoSET insulation system is tailored to MV cable production, and should therefore be compared to similar kinds of grades. Quite often these are water-tree retardant XLPE compounds with different properties to HV/EHV XLPE grades. The thermal conductivity of pure polypropylene is lower than that of polyethylene. With polypropylene copolymers, however, the difference is not as great. Together with development partner HV Cable Solutions, Rosendahl carried out ampacity calculations with different XLPE and PPC grades for a single 20 kV cable. The results showed that the

▲ ▲ RoSET polypropylene-based compound press

that it had to advise cable producers to take care of cross contamination when changing from one material to another, and to be particularly careful when handling the materials in general. On this basis, a special material-handling system has been developed. Rosendahl recommends a dedicated horizontal MV PPC insulation line to avoid problems and to ensure successful test and production runs. As the PPC technology develops towards higher voltages and different properties, Rosendahl will continue to be part of that development.

polypropylene compound cable can have better current-carrying capacity and transmission capacity, and lower electrical losses at 90°C, and that the cable can also be run at 110°C, if necessary. This was also the case in auxiliary tests when a similar MV XLPE cable was compared to an MV PPC cable. Rosendahl extensively tested RoSET MV PPC in its laboratory and also with complete production runs on an installed line. Over the past 18 months the company has had a dedicated extrusion setting for the RoSET insulation system compounds with high and stable performance.

Rosendahl Nextrom GmbH www.rosendahlnextrom.com

During the real cable runs, it also found

Bobbin winder lines

The company carries out continuous training to improve production quality, and has established a quality laboratory in its new factory. Sarmakina’s bobbin winder lines, for the bobbins that feed braiding machines, are used in cable and wire factories from Brazil to the UK. After completing the requirements of sister companies Sarkuysan, Sark Wire and Sark Bulgaria for double-twist bunching machines, the company has started to meet the needs of its other customers. Its bunching machines have begun operation at companies in Turkey and Europe, and the number of payoffs running around the world is approaching 1,000. Sarmakina Sanayi ve Ticaret AS www.sarmakina.com.tr

Sarmakina is a manufacturing, engineering and contracting company that was founded in 1991 by Sarkuysan AS, a major copper wire manufacturer in Turkey. Its main products are machines (motor-driven payoffs and spoolers, bunching machines, bobbin winders, rewinding lines, emulsion systems, filters and tin plating lines) supplied to the wire and cable industry, as well as standard and custom-made steel reels. The company also carries out manufacturing, subcontracting and contracting works, and steel construction works. During the next year, the company’s main export targets are European countries, and the USA and Russia. Demand for Sarmakina’s products have increased because of European companies’ investment in new machinery and their desire to expand production.

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May 2020