A DIELECTRIC GELLING COMPOSITION, A METHOD OF MANUFACTURING SUCH A DIELECTRIC GELLING COMPOSITION AND AN ELECTRIC DC-CABLE COMPRISING AN INSULATION SYSTEM IMPREGNATED WITH SUCH A DIELECTRIC GELLING COMPOSITION

摘要

A dielectric gelling composition, exhibiting a thermo-reversible liquid-gel transition at a transition temperature, Tt, wherein the gel comprises an oil and a gelator with a block copolymer comprising an olefin based block and at least one further block comprising aromatic rings in its backbone structure, wherein each one of the two blocks has a molecular weight of more than 3000 g/mole, and the block with aromatic rings in its backbone structure exhibits a rigid backbone structure and a temperature dependent solubility in the oil, is disclosed. The gelling composition is produced by preparing the block copolymer by means of a condensation reaction and subsequently adding the resulting copolymer to an oil at a temperature above the transition temperature of the gelling composition. The gelling composition is used as an impregnant in an insulated direct current cable having at least one conductor and an impregnated insulation system. The insulation system comprises a solid electrically insulating dielectric part with a porous, fibrous and/or laminated structure impregnated with a dielectric gelling composition.