This technology transition is a natural development due to the increasing demand for transmission of larger amount of power over longer distances. A single pair of 525 kV extruded HVDC power cables can transmit enough power to supply approximately two million households. By implementing these power transmission highways into the electrical grid utilizing HVDC technology we can ensure the safe, efficient and low loss transport of electrical energy from wherever it is produced to wherever it will be required - no matter the physical distance. Here, the innovative and proven XLPE insulation is key as it has excellent DC insulation properties.
The development of DC XLPE technology
Since its introduction in the late 1990’ies, XLPE DC cables systems, together with the associated converter technology, have provided the fundamental platform for HVDC power transmission. The development and commercial introduction of XLPE HVDC cable systems starting at 80 kV level grew rapidly to 150 kV and was followed by 200 kV and subsequently 320 kV, which inherently also finally raised the transmission capacity towards and above1GW. These systems are all based on the same extruded cable technology platform and in order to reach even higher voltage levels, and thereby increased transmission capacity, a continuous improvement of the XLPE insulation material was needed. The improved material system together with NKT’s HVDC know-how and advanced field grading technology now provides an even stronger platform for reaching such higher voltage levels allowing transmission of 2GW per HVDC cable system.
As the transition to renewable energy is expected to accelerate the further development of an interconnected regionally, or in time even a globally, connected power grid needs to follow. This will create an increasing demand for transmission of larger amount of energy with low losses which will be driving the technology development and innovation. One natural next step following the 525 kV XLPE DC technology could be the commercialization of 640 kV XLPE DC onshore cable system
which we launched in 2017 as the first in world. This development has been made in continuation of the 525 kV technology launched in 2014.
Efficient transmission of renewable power
A central part of the environmental footprint of any high-voltage power cable system is determined by the losses aggregated during the lifetime of the system. When using XLPE HVDC for transmission of renewable power the losses are very low. This means that almost all the power sent in to the cable also reach the end of the cable, ensuring a higher output of electricity to be fed to the transmission networks over the system’s lifetime. This ensures that power generated from wind, hydro or other renewable sources are used efficiently.
At NKT, we ensure that our cable system is manufactured with a low carbon footprint, all our factories operate on renewable electricity and we are constantly working to reduce the carbon footprint of our production, installation and supply chain.
If we – as a society - shall reach the target of being carbon neutral in Europe by 2050, all parties must contribute. At NKT, we are committed to do our part in making Europe a carbon neutral continent with manufacturing and installation of robust and reliable DC cable systems.