There are in principle two different types of paper insulated cables:
- Self Contained Fluid Filled (SCFF) cables
- Mass Impregnated (MI) cables
The main difference between the two is the type of fluid used for impregnation of the paper. For SCFF cables, insulating fluid (low viscosity) is used and for MI cables insulating mass (high viscosity) is used.
The SCFF cable may be used both for HVAC and HVDC applications, but the maximum length of a SCFF cable link is limited to approximately 50 km because of the need of fluid feeding into the cable. The MI cable is solely used for HVDC, and there is no limitation in maximum length for a MI cable.
SCFF cables are used for the highest AC voltages, and already in the early eighties Nexans installed the first 525 kV SCFF submarine cable link. Nowadays such cables are used for extra high power transmission capacity links at the highest voltages.
Mass impregnated HVDC cables are the preferred solution for long distance submarine transmission of large amount of electrical energy at the highest voltages. Through decades this technology has been in service for a large number of power transmission links and has proven excellent reliability at a voltage up to 525 kV and a power rating exceeding 800 MW per cable. Mass impregnated HVDC cables from Nexans are employed for major submarine cable projects, and is the chosen technology for long submarine interconnections. Examples of MI HVDC interconnection projects utilizing this mature and well proven cable technology from Nexans are Sweden – Finland (Fenno-Skan), Norway – Denmark (Skagerrak), Montenegro – Italy (Mon.Ita), Norway – Germany (NordLink) and Norway – UK (NSL).
To meet the future market demand Nexans is constantly developing the mass impregnated cable system for higher power rating and more demanding installation scenarios, ex. greater installation depths. Nexans’ leading position in the market is demonstrated through decades of successful realization of mass impregnated HVDC cable projects, and proves that mass impregnated cables are highly competitive for the future realization of high power HVDC cable transmission systems.
For a general description of the paper insulated cables constituents - choose the tab "docs and info" / "relevant informasjon".