Mixture of hydrofluoroolefine and hydrofluorocarbide to improve the internal ARC resistance in medium and high voltage electric apparatus
The invention relates to the use of a mixture of a hydrofluoroolefin and a hydrofluorocarbon, optionally combined with another fluorinated gas, as an electrical insulation medium and/or an electric arc extinguishing medium in a medium-voltage electrical apparatus. The invention also relates to a medium- or high-voltage electrical apparatus in which such a mixture provides electrical insulation and/or electric arc extinguishing.
1. A method of extinguishing electrical arcs, comprising:
providing a gas medium to extinguish the electrical arcs,
wherein the gas medium comprises at least one hydrofluoroolefin with three carbon atoms and one hydrofluorocarbon.
2. The method according to claim 1 , wherein the hydrofluoroolefin is trans-1,3,3,3-tetrafluoro-1-propene, 2,3,3,3-tetrafluoro-1-propene or 1,2,2,5-pentafluoro-1-propene.
3. The method according to claim 1 , wherein the hydrofluorocarbon is 1,1,1,2,3,3,3-heptafluoropropane, pentafluoroethane or 1,1,1,2-tetrafluoroethane.
4. The method according to claim 1 , wherein the gas medium further comprises a fluoroketone.
5. The method according to claim 1 , wherein the gas medium further comprises a dilution gas, wherein said dilution gas is air, oxygen, carbon dioxide or a mixture thereof.
6. The method according to claim 1 , wherein partial pressure of the hydrofluorocarbon and of the hydrofluoroolefin in the gas medium is chosen as a function of a minimum temperature of an apparatus so as not to create a liquid phase according to Raoult's law at a minimum temperature of use of the apparatus.
7. The method according to claim 6 , wherein the apparatus is a high or medium voltage electrical substation.
8. The method according to claim 6 , wherein the minimum temperature (T min ) is −30° C., −25° C., −15° C. or 0° C.
9. The method according to claim 4 , wherein the fluoroketone is decafluoro-2-methylbutan-3-one.
10. A medium voltage electrical apparatus comprising:
a sealed chamber containing electrical components; and
a gas medium, wherein the gas medium comprises a hydrofluoroolefin with three carbon atoms and a hydrofluorocarbon.
11. The electrical apparatus according to claim 10 , wherein
the hydrofluoroolefin is trans-1,3,3,3-tetrafluoro-1-propene, 2,3,3,3-tetrafluoro-1-propene, or 1,2,2,5-pentafluoro-1-propene, and
the hydrofluorocarbon is 1,1,1,2,3,3,3-heptafluoropropane, pentafluoroethane, or 1,1,1,2-tetrafluoroethane.
12. The electrical apparatus according to claim 10 , wherein the gas medium further comprises a dilution gas.
13. The electrical apparatus according to claim 12 , wherein the dilution gas is air, oxygen, carbon dioxide, or a mixture thereof.
14. The electrical apparatus according to claim 10 , wherein the hydrofluoroolefin and the hydrofluorocarbon are present in the gas medium with proportions defined according to Raoult's law so as not to create a liquid phase at a minimum temperature of use of the apparatus.
15. The electrical apparatus according to claim 10 , wherein said electrical apparatus is an electrical transformer with gas insulation, a line with gas insulation for transporting or distributing electricity or a connecting/disconnecting electrical apparatus.
16. The method according to claim 2 , wherein the hydrofluorocarbon is 1,1,1,2,3,3,3-heptafluoropropane, pentafluoroethane or 1,1,1,2-tetrafluoroethane.
17. The method according to claim 16 , further comprising adding a dilution gas to the gas medium, wherein the dilution gas is air, oxygen, carbon dioxide or a mixture thereof, and
wherein partial pressure of the hydrofluorocarbon and of the hydrofluoroolefin in the gas medium is chosen as a function of a minimum temperature of an apparatus so as not to create liquid phase according to Raoult's law at a minimum temperature of use of the apparatus.
18. The electrical apparatus according to claim 13 , wherein said electrical apparatus is an electrical transformer with gas insulation, a line with gas insulation for transporting or distributing electricity or a connecting/disconnecting electrical apparatus.
19. The electrical apparatus according to claim 15 , wherein the hydrofluoroolefin and the hydrofluorocarbon are present in the gas medium with proportions defined according to Raoult's law so as not to create liquid phase at a minimum temperature of use of the apparatus.