Abstract:
A HV power transmission line (106) with at least two tubular electrical insulation devices (108), at least one electrically uninsulated nominal conductor segment (102) and a joint (1 17) for jointing the ends of the insulation devices plus at least one power termination (109) for connecting the transmission line. The insulation device (108) is flexible, has an inner electrically conductive layer (1 10) at its inner wall surface, and is of such insulation quality that it can electrically insulate the conductor segment (102) from the exterior of the insulation device once inserted into the tubular insulation device. Once inserted the uninsulated conductor segment touches the inner electrically conductive layer (1 10) at an inner wall surface of the tubular electrical insulation device such that the inner electrically conductive layer (1 10) is on the same electric potential as the conductor segment in an operating state of the HV power transmission line each.
Abstract:
The present invention relates to a material comprising reduced graphene oxide, wherein the degree of reduction of the graphene oxide exhibits a spatial variation so that the material exhibits a gradient in the electric conductivity and/or permittivity. The material can for example be used in an electric device for purposes of field grading and/or dissipation of charges. Examples of electric devices wherein the material is beneficial includes cable accessories, bushings, power cables, microelectronics, switchgear, etc. The invention further relates to a method of producing a material for electrical applications. The method comprises treating different parts of a graphene oxide element differently, so as to achieve a different degree of reduction of the graphene oxide within the element, resulting in a sample having a gradient in the electrical conductivity and/or permittivity. The material could for example be obtained by means of applying a thermal gradient to a graphene oxide element, or by irradiation of a graphene oxide element.