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 3.0 ppm; wherein the thermoplastic polyethylene is multimodal, and is a medium density ethylene copolymer or a high density ethylene homopolymer or copolymer.
2. A power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition is a thermoplastic 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 (HV) and/or extra-high voltage (EHV) power cable insulation polymer composition.
4. 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.
5. A power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition has a DC electrical conductivity of 45 fS/m or less.
6. A power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition has a DC electrical conductivity of 10.0 fS/m or less.
7. A power cable insulation polymer composition according to claim 1 , wherein X is 2.5 ppm.
8. A power cable which power cable comprises a polymer composition being, or comprising, the power cable insulation polymer composition according to claim 1 .
9. A power cable polymer insulation, for example, a high voltage direct current (HV DC) and/or an extra high voltage direct current (EHV DC) power cable insulation, which power cable insulation comprises a polymer composition being, or comprising, the power cable insulation polymer composition according to claim 1 .
10. 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.
11. The method according to claim 10 , wherein the power cable is a direct current (DC) power cable.
12. The method according to claim 10 , wherein the insulation layer comprises 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 multimodal, and is a medium density ethylene copolymer or a high density ethylene homopolymer or copolymer.
13. The power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition does not comprise an acid scavenger.
14. The power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition does not comprise an ion scavenger.
15. The power cable insulation polymer composition according to claim 1 , wherein the thermoplastic polyethylene 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.
16. The power cable insulation polymer composition according to claim 1 , wherein the thermoplastic polyethylene is the sole polymer component.
17. The power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition has a DC electrical conductivity of 5.0 fS/m or less.
18. The power cable insulation polymer composition according to claim 1 , wherein the power cable insulation polymer composition has a DC electrical conductivity of 4.0 fS/m or less.
19. The power cable insulation polymer composition according to claim 1 , wherein X is 1.0 ppm.
20. The power cable polymer insulation composition according to claim 2 , wherein the power cable insulation polymer composition is a high voltage (HV) and/or extra-high voltage (EHV) power cable insulation polymer composition.