Speaking About Big Cables

The tendency in high (HV) and extra high (EHV) voltage applications is towards bigger cables, up to diameters of 200 mm. To reduce the outer diameter of the cables, a smooth Al-sheathing has been introduced as an alternative to the conventional corrugated metal sheath. To guarantee necessary adhesion between the smooth Al-sheath and the PE- sheath, an adhesive layer is applied between the two. Most HV and EHV cables have a semiconductive skin layer for testing purposes.

Three layer simultaneous extrusion

We have developed a new Three Layer Co-extrusion Crosshead ECH 200/240 3L to apply all three layers on the cable core simultaneously. Since sheathed products are heavy and big in diameter, user friendliness and space requirements have been taken into account. Our design allows placing all three extruders on the same side of the line, leaving the operator side of the line free. The distributors are mounted on slides to make dismantling and cleaning easy and safe.

Advanced material flow simulations were used in designing the distributors. The new design allows distribution of a thin even layer over the cable circumference which can be more than 620 mm.

Benefits

•     Three layer co-extrusion
•     Single layer or single layer plus skin
•     User friendly
•     Can handle common sheathing materials like PE, PVC or HFFR.