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Technical article
May 2017 49
Sikora AG
Bruchweide 2,
28307 Bremen,
Germany
Tel: +49 421 489 000
Email :
Website:
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.
Furthermore, the paper 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
the discharge tests can be saved and the
efficiency of the cable production line is
improved to a great extent. n
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]
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 (20th-23rd
September 2010)