Loss reduction in cable sheathing

Abstract

In order to reduce electric potential difference between the sheathings of single core three-phase cables, the sheathing is grounded and bonded at one or both ends of the cables. If the cable is long, double bonding has to be carried out which leads to circulating currents and increased power loss. Based on finite element (FE) calculations, this paper shows, that raising the sheath's resistance, by decreasing its cross section and increasing its resistivity, can significantly reduce this loss. The magnetic field close to the ground surface and the behaviour of the cable during fault conditions are also investigated.