EoW March 2009

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EuroWire – March 2009 90
Power cable manufacturing,
materials & machinery
Rotating machines for the production
of HV/EHV transmission lines
Cloth tapes
for cables
Neptco’s Powerline® cloth tapes used in
power cables are designed to separate,
shield, identify and insulate power cable
components, thereby reducing the
incidence of failure and extending the
life of power cables.
Neptco’s Aquablok® water blocking
tapes are designed to protect power,
telecom and fibre optic cables from
the damaging and corrosive effects
of water penetration and migration.
Aquablok® tapes are available in a
wide variety of constructions
including woven, non-woven, single-
and double-sided, formulated with
either insulative or semi-conductive
properties. Neptco has manufacturing
and distribution locations strategically
located to supply multinational wire
and cable manufacturers and will now
service the European market with a
new distribution facility in Rotterdam,
Netherlands for its Powerline®Aquablok ®,
Lightline® , and Flexline® products.
Neptco – USA
Fax: +1 401 722 6378
Email:
Website:
Gauder Group has always been active in the development of equipment for the
manufacture of power cables, from low and medium to high and extra high voltage.
Setic–Gauder Group designs and manufactures bunchers and large double twist
stranding lines, while Pourtier is highly experienced in laying-up drum twister and
modern stranding machines for copper conductors as well as large armouring and
screening lines. The manufacturing process starts with the production of the copper
conductor. For large conductors, the Milliken construction is used. The purpose is to
reduce the “skin effect” thus permitting a better distribution of current in the conductor.
The conductor mainly consists of 4, 5, 6 or 7 segments. Each segment is made up of
wires, stranded and shaped in a rigid stranding machine, separated from one another
by tapes during laying-up process.
The stranding of sector shaped conductor, pre-spiralled, for high voltage cable, requires
care. For this purpose, Pourtier has designed a rigid stranding machine for large reel size
making possible the production of long lengths without welding. Special care has been
paid to tension control on each wire, with automatic correction between full bobbin
and empty bobbin and possible adjustment from the control desk during machine run.
Special rotating heads ensure the necessary high quality of compacting, shaping and
pre-spiralling of the conductor. Furthermore, a new side-loading system has been
designed, allowing bobbin preparation during machine run (idle time) thus reducing
down time and increasing machine efficiency.
High voltage cable conductor must be handled with great care to prevent any damage
or even any mark on the surface, deformation, incorrect alignment or contamination
by foreign matter. The drum twister machine designed by Pourtier integrates all
parameters to fit with severe production requirement of high voltage power cable
including smooth deviation angle for the segments as well as for the laid-up conductor
(resulting in a longer take-up frame). Tension control on each segment is of utmost
importance for laying-up of Milliken cable to ensure perfect geometry of the finished
conductor. A correction system is used to automatically adjust the relative position of
each segment before entering into the laying-up block: up to five sensors are constantly
controlling the position of the five segments and giving feed-back to each rotating
pay-off stand whose rotation speed is automatically adjusted. No pressure or forcing is
exerted on the segment, which is of paramount importance for the final quality of the
product.
Before entering into the stranding block, several tapes are longitudinally applied
between the segments. This method requires particular attention: special guiding
and tension control for each tape has been developed to ensure a precise insertion of
the tapes in between the segment without any damage to these tapes. When laid-up,
the segments form a tight, close-fitting construction. The segments are then taped
together with semi-conductive tapes. The line also includes all possible facility to ensure
complete water tightness of the cable.
Gauder Group – France Fax: +33 1 64 26 61 10
Email: Website:
Drum twister line for Milliken laying-up ▲ ▲