EuroWire September 2021

Technology News

High-speed curing Maillefer Extrusion Oy recently com- missioned several of its fastest and most advanced high-voltage VCV lines to date. The lines are equipped with Round Value Package Premium curing technology, which enables high-speed curing without the problems normally found with increased line speed.

and shrinking, specifically at the curing and cooling sections of the CV line. Round technology allows the curing power of the CV tube to be increased without any issues. Curing can be started efficiently, while increasing the total curing power without negative side effects. More curing power leads to higher production speed. Maillefer states that its CV lines are now producing multiple submarine cable campaigns at a speed of 1.55m/min for a 220kV 400mm 2 copper conductor cable core. As high speed should not be at the expense of quality, Round technology also provides results in terms of cable core ovality. Typically, thick insulation layers with small conductors can be demanding constructions. The Round technology enables production of cores with 0.995 roundness. Maillefer’s screw development aims for higher extrusion output without areas of low flow or stagnation points. Streamlined designs are successful in realising the long production campaigns necessary for submarine cable manufacture.

Maillefer’s latest lines are equipped with Round Value Package Premium curing technology ▲

The addition of Round tech- nology has also made it possible to utilise the full output available from the insulation extruder. Without constraints based on curing power and cable core roundness, a higher screw

The insulation process for high-voltage submarine cables is complex, and re- quires the balancing of factors such as production length, production time and production speed. While higher speeds are beneficial to achieve longer lengths in shorter time, production speed is limited by cable core geometry, curing power and extruder performance. With typical technology, cable core ovality starts to increase significantly when increasing speed and the related curing power. Round curing includes technological innovations designed to remove these challenges. With a special heat impulse, the curing process begins by forming a cross-linked layer on the outside of the core in an efficient manner. This outer cross-linked layer maintains a round cable core during heat expansion

speed can be used, reducing the time that insulation material resides inside the extruder and crosshead. According to Maillefer, projects consisting of 120 tons of insulation material can be realised in less than 12 days. Examination of breaker plates and fine mesh filters after such long campaigns have shown no signs of XLPE material stagnation or scorch. Maillefer Extrusion Oy www.maillefer.net

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September 2021