Direct Current (DC) Cables

In order to keep pace with society’s growing energy demands, power utilities increasingly have to contract for the delivery of electricity supplies from ever more distant sources. 

This trend is challenging utilities to develop networks able to overcome the transmission-distance limitations presented by traditional lapped, fluid filled cable, direct current (DC) systems, as well as to reduce energy losses and improve transmission reliability. 

To help cable makers and energy distributors meet these challenges, Borealis has developed special Superclean™ crosslinked polyethylene (XLPE) insulation compounds and Supersmooth™ semiconductive materials specifically for the manufacture of DC transmission cables.  Designed for both underground and sub-sea operating environments, Superclean™ XLPE insulated cable offers the power distributor:

• faster installation;
• lower environmental impact - elimination of fluid leakage risk;
• higher operating temperature;
• low dielectric losses;
• better power flow control;
• improved transmission reliability and reduced risk of network failure.

Cleanliness ensures good electrical performance

Designed for HVDC operating conditions and system voltages up to 150kV, Superclean™ XLPE insulation compounds are produced in contamination-free environments and delivered in Superclean octabins filled and emptied under clean room conditions. This provides the highest level of cleanliness, reduced risk of degradation by contaminants, and consistent performance with long-term reliability.

Importantly for the cable maker, Superclean aids manufacturing through:

• better scorch safety;
• longer production runs before equipment needs to be cleaned;
• lower degassing burden;
• shorter production cycles by 10-20%.

Semiconductive screening materials add value to HVDC cable

At higher electrical stresses a smooth interface between insulation and shielding increases the potential for reliable performance and uninterrupted power supply.  Supersmooth™ semicons have been optimised to provide the semiconductive layers on both sides of the Superclean XLPE insulation with very smooth and even surfaces that:

• eliminate surface pips;
• reduce electrical stresses;
• minimise the risk of power failure.