technology | Wire and cable Right: Borlink
extruded HVDC technology has set a new
power trans-
mission record at 640 Kv
with formulations for high voltage direct current (HVDC) cable. They say a cable system based on Borlink LS4258DCE unfilled XLPE compound and semicon Borlink LE0550DC recently achieved a world record of 640 kV. “This innovative material technology enables the efficient delivery of even more transmission capacity over longer distances, better interconnectivity among countries and grids, and better connection of renewable energy sources to future grids,” the companies say. “This new step-change in electrical performance has been made possible due to the unique properties offered by tailored polymers based on Borlink, in combination with the high levels of chemical and physical cleanliness these compounds offer.” The innovation was developed in partnership with NKT cables. Borealis says that one pair of 640 kV HVDC extruded cables can transmit over 3 gigawatt (GW) of power, equal to the combined output of the six biggest hydroelectric power plants in Sweden, and enough to supply about three million households. Carbon black is a critical component in the overall
power cable design since it provides the required conductivity and ease of stripability in semicon shield compounds. Himanshu Patel, Technology Manager with Birla Carbon Specialty Blacks, says that with carbon black loadings ranging from 35% to 45%, the carbon black has a significant impact on the ultimate cable performance. “In power cables, the smoothness at the interface between the insulation layer and semicon shield is critical for the endurance of power cables,” he says, noting that Birla’s Conductex carbon blacks are designed to minimise the micro-protrusions from semicon shields, reducing the risk of localised electri- cal stress and electrical degradation. At Imerys Graphite & Carbon, Development
Scientist Daniele Bonacchi says the company has observed growing demand for its Ensaco carbon black for conductive jacketing applications in recent years. Conductive jacketing, mainly used in MV, HV and EHV cable systems, is replacing graphite coating, which has the potential drawback of partial removal during installation, especially in duct systems and tunnels. “Conductive jacketing is preferred as it more resist- ant,” Bonacchi says. “Moreover, a conductive jacketing provides continuous grounding, giving additional protection from surges and transient currents in the event of a lightning strike. The fact that grounding is less frequent is very important in submarine cables where underwater grounding can be very expensive. Ensaco
26 COMPOUNDING WORLD | May 2017
conductive and extraconductive carbon black are preferred due to the very high conductivity, excellent dispersion and high purity.” Bonacchi also cites increasing
demand for Ensaco carbon blacks for HV semiconductive compounds, espe- cially in European and Asian countries. Better dispersibility and higher conduc- tivity than acetylene black can lead to higher performance at the same loading. Moreover, the possibility of reducing the loading
while maintaining excellent electrical properties opens the door to a reduction of viscosity and increase of the scorch time, which should reduce the risk of premature crosslinking in the extruder. Ensaco grades also have extremely low moisture uptake, helping reduce cable degradation in high electrical fields.
Driving developments More compact engine compartments and the move to hybrid and electric power trains are placing new demands on automotive electrical systems. Germany- based Melos has developed a range of cable com- pounds for higher temperature resistance in primary wiring applications such as battery cables. The Mecoline RDX range consists of six thin-wall insulation compounds including full- or semi-flexible and oil-resistant compounds. The halogen-free Mecoline I RDX 1213 F and Mecoline I RDX 1229 F grades are suitable for operating temperatures up to 125°C and are described as fast-curing, radiation cross-linkable formulations. Halogenated Mecoline RDX compounds are designed for operating tempera- tures in the 150-225°C range, with fluoropolymer-based grades used for temperatures over 200°C.
Click on the links for more information: ❙
www.dowcorning.com ❙
www.evonik.com ❙
www.wacker.com ❙
www.elkem.com ❙
www.hubermaterials.com ❙
www.teknorapex.com ❙
www.mexichemspecialtycompounds.com ❙
www.addivant.com ❙
www.adeka.co.jp/en ❙
www.sespoly.com ❙
www.borealisgroup.com ❙
www.borouge.com ❙
www.birlacarbon.com ❙
www.imerys-graphite-and-carbon.com ❙
www.melos.com
www.compoundingworld.com
PHOTO: NKT
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