Power cable polymer composition comprising thermoplastic and having advantageous properties
The invention relates to power cable polymer composition which comprises a thermoplastic polyethylene having a chlorine content which is less than X, wherein X is 10 ppm, a power cable, for example, a high voltage direct current (HV DC), a power cable polymer insulation, use of a polymer composition for producing a layer of a power cable, and a process for producing a power cable.
1. A power cable insulation polymer composition comprising a single site thermoplastic polyethylene having a chlorine content which is less than X, wherein X is 10 ppm; wherein the thermoplastic polyethylene is the sole polymer component, is multimodal and is a medium density ethylene copolymer of ethylene and one or more C 3 -C 20 alpha-olefins; or a high density ethylene homopolymer or copolymer of ethylene and one or more C 3 -C 20 alpha-olefins; wherein the power cable insulation polymer composition does not comprise an acid scavenger, and wherein the power cable insulation polymer composition has a DC electrical conductivity of 4.0 fS/m or less.
2. A power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition is a high voltage (HV) and/or extra-high voltage (EHV) power cable insulation polymer composition.
3. A power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition is a high voltage direct current (HV DC) and/or an extra high voltage direct current (EHV DC) power cable insulation polymer composition.
4. A power cable insulation polymer composition according to claim 1 , wherein X is 5.0 ppm.
5. A power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition comprises a chromium catalyst polyethylene with a density of 930 to 949 kg/m 3 .
6. A power cable which power cable comprises a polymer composition being, or comprising, the power cable insulation polymer composition according to claim 1 .
7. A method of producing a power cable with the insulation polymer composition of claim 1 comprising: producing at least one layer of a power cable with the composition, said power cable comprising a conductor surrounded by at least an inner semiconductive layer, an insulation layer and an outer semiconductive layer, in that order.
8. The method according to claim 7 , wherein the power cable is a direct current (DC) power cable.
9. A power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition does not comprise an ion scavenger.