EuroWire May 2017

Technical article

the discharge tests can be saved and the efficiency of the cable production line is improved to a great extent. n

For comprehensive process optimisation cable manufacturers combine an online inspection and sorting system with an offline inspection and analysis device. Once contaminated pellets have been detected and sorted out, the laboratory system inspects these pellets again and marks contamination optically for an easy separation of all rejects. This interaction of online and offline inspection and analysis enables control of the material purity and allows the creation of a database to prevent future contamination. Conclusion In summary, this paper outlined the reasons for the need of a high purity degree of XLPE and HPTE material used for the insulation of MV and EHV cables. introduced systems for on- and offline quality control of XLPE and HPTE that inspect the material before processing. The presented inspection and sorting system detects contaminated pellets and separates them before they get into the extrusion process. The contamination may be in the raw material, but may have also been added at the handling and transport stage. Accordingly, even if cable manufacturers keep on using screens, this technology assures that screens are not getting clogged with impurities from contami- nated pellets and allows, therefore, a longer and safe production run. By using X-ray and optical technologies contaminants inside and on the pellet surface are detected, which guarantees 100 per cent quality control. With the use of an offline inspection and analysis system for contaminated pellets that had been separated by the online inspection system, production processes can even be improved. The material purity is controlled and the analysis gives information to prevent future contamination. Taking these advantages together, the use of the introduced technologies for quality control of XLPE and HPTE material is essential to assure high-quality MV and EHV cables. Simultaneously, by ensuring a high purity degree of XLPE and HPTE material, cost for re-manufacturing cables that failed Furthermore, the paper

References

[1] Conference Paper in Electrical Insulation, 1988, Conference Record of the 1988 IEEE International Symposium on July 2010, S Belli, G Perego*, A Bareggi, L Caimi, F Donazzi, E Zaccone, Prysmian SpA, P-Laser: breakthrough in power cable systems [2] http://www.leadercable.com.my/dl/leader-xlpe. pdf [3] Chinese standard IEC 62067 (for 150-500kV) in J Kjellqvist, K P Pang, S Miao, Dow Europe GMBH, Horgen, Switzerland, Dow Chemical (China) Co Ltd, Shanghai, China, Performance Requirements to Assure Reliable HV and EHV Cables, China International Conference on Electricity Distribution (CICED 2010) Nanjing (20 th -23 rd September 2010)

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May 2017