High Voltage - NKT Cables - #4

Design and Manufacture

A wide variety of high voltage cable designs is offered by nkt cables to provide most eco­nomic solutions. Various types of conductors, insulation, metallic screening and sheathing,

corrosion protective layers etc. are available. Conductors

The cable conductors can be made of copper or aluminium. The choice is a matter of customer's preference or current carrying capacity. Large size solid conductors are made of aluminium.

V round solid conductors up to 2000 mm² (RE)

V circular stranded compacted conductors up to 1200 mm² (RM)

V circular conductors with shaped wires up to 2000 mm² (RM, Keystone conductors)

V segmental conductors up to 2500 mm² (RMS, Milliken conductors)

V oval shaped stranded compacted con­ductors up to 800 mm² for external gas pressure cables (OM)

The conductors are manufactured to meet

the requirements of the relevant national and international standards. For special applica­tions the conductors can be made watertight.

The insulations for low pressure oil filled

cables and for conventional pipe type cables

are lapped from high quality insulating papers. Subsequently the paper insulated

cable cores are impregnated in appropriate vessels with low viscous oil or high viscous compound.

For manufacture of XLPE insulated high voltage cables, nkt cables disposes of four extrusion lines. Highest quality standards

together with latest process control equip­ment and combined with decades of

experience ensure manufacture of cables

meeting the highest requirements and

enabling development of most advanced

power cable systems. Metallic Covering

Conventional paper insulated cables require a pressure proof and watertight metallic

enclosure, acting also as metallic screen. At nkt cables both, extruded lead sheath as well as the aluminium sheath can be applied.

These types of metal sheaths are, of course,

also used on XLPE insulated cables. While the

lead sheath leads to smaller dimensions, the aluminium sheath provides high short circuit

current carrying capability and lower weight.

As the XLPE insulated cables do not require

an internal overpressure, they are usually

equipped with a copper wire screen. For radi­al moisture barrier a coated aluminium foil is longitudinally applied. The combination with the polyethylene oversheath is called alumini­um polyethylene laminated (APL) sheath. This solution provides high short circuit capability and watertightness combined with lowest weight and smallest dimensions.

A combination of the copper wire screen with a metal sheath is also possible. For all XLPE

insulated high voltage cables, the space between cable core and water barrier is made longitudinally watertight.

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