Polymer composition and a power cable comprising the polymer composition

A polymer composition which is crosslinkable, wherein the polymer composition comprises a polyolefin and a crosslinking agent, and wherein the polymer composition has an electrical conductivity of 150 fS/m or less, when measured at 70° C. and 30 kV/mm mean electric field from a non-degassed, 1 mm thick plaque sample consisting of a crosslinked polymer composition via determination of the current through the plaque after 24 hours;

• wherein the composition is suitable for use in a layer of a direct current (DC) cable;
• and
• wherein the polyolefin is an unsaturated LDPE polymer, which is selected from an unsaturated LDPE homopolymer or an unsaturated LDPE copolymer of ethylene with one or more comonomer(s), and wherein the unsaturated LDPE polymer contains vinyl, maws and the total amount of vinyl groups present in the unsaturated LDPE is higher than 0.05/1000 carbon atoms,
• wherein the polyolefin is obtained by a high pressure process comprising
• (a) compressing one or more monomer(s) under pressure in a compressor, using a compressor lubricant for lubrication,
• (b) polymerizing a monomer optionally together with one or more comonomer(s) in a polymerization zone,
• (c) separating the obtained polyolefin from the unreacted products and recovering the separated polyolefin in a recovery zone,
• wherein in step a) the compressor lubricant comprises a mineral oil.