Evolution of Medium Voltage Cable Technology in Europe

This paper presents the evaluation of the performance of these cables in the field and to review the improvements that have been made within Europe. In the early 1980s, the first generation of medium voltage cables were made with graphitized outer screen, double extrusion, polyvinylchloride (PVC) sheaths, and classic homo-polymer XLPE insulation. Because these cables demonstrated early failures in the field, cable makers introduced triple extrusion and extruded outer screens using semiconducting material instead of graphite. Additionally, the jacketing was changed from PVC to medium density polyethylene (MDPE), and later to high density polyethylene (HDPE). Compound producers also improved the cleanliness of their compounds and developed the so-called polymer water tree retardants (WTR) [1]. In this paper, we discuss the performance of medium voltage (up to 36 kV) cables, and the effects of changes made to production methods.