New developments in the field of high-voltage and extra high-voltage cables: the user´s point of view

Synthetic extruded cables have been successfully used in France for 63 kV and 90 kV grids since 1962 and for the 245 kV grid since 1969, and they were introduced in the 420 kV network in 1986. The operating results are found to be particularly good. This is attributed to the manufacturing process, long-term testing to assess aging and compatibility of the components, and acceptance tests based on expected reliability in service. New developments are under consideration: new laying and installation methods, optimization of the cross-section of the conductors, prefabricated joints for EHV cables, and high-voltage fluid-free terminations. Particular attention is given to the extruded insulation behavior under DC voltage