USE OF A LINEAR OCTAFLUOROBUTENE AS A DIELECTRIC COMPOUND IN AN ENVIRONMENTALLY SAFE DIELECTRIC-INSULATION OR ARC-EXTINCTION FLUID

Abstract

The present invention relates to the use of a linear octafluorobutene as a dielectric compound in an environmentally safe dielectric-insulation or arc-extinction fluid for an apparatus for the generation, the transmission, the distribution and/or the usage of electrical energy.

Claims

1. A combination, comprising: a linear octafluorobutene utilized as a dielectric compound in an environmentally safe dielectric-insulation or arc-extinction fluid for an apparatus for the generation, the transmission, the distribution and/or the usage of electrical energy, wherein the proportion of the linear octafluorobutene dielectric compound in the dielectric-insulation or arc-extinction fluid is at least 3%.

2. The combination according to claim 1, wherein the dielectric-insulation or arc-extinction fluid is non-ozone depleting and has a Global Warming Potential over a time horizon of 100 years of less than 10.

3. The combination according to claim 1, wherein the dielectric-insulation of arc-extinction fluid is inert towards the material of the apparatus, with which the fluid gets into direct contact during its use in the apparatus.

4. The combination according to claim 1, wherein the median lethal dose (LC50; lethal concentration 50%; measured on rats) of the dielectric compound is higher than 4000 ppm.

5. A dielectric-insulation or arc-extinction fluid for an apparatus for the generation, the transmission, the distribution and/or the usage of electrical energy, the fluid comprising: a) a linear octafluorobutene as a first component A in mixture with b) a second component B different from the first component A, the proportion of the first component A in the dielectric insulation of arc-extinction fluid being at least 3%.

6. The dielectric-insulation or arc-extinction fluid according to claim 5, the dew point of which being below the minimum operating temperature of the apparatus.

7. The dielectric-insulation or arc-extinction fluid according to claim 5, having a dew point of lower than 20 C., wherein the partial pressure of component A as measured at 293.15 K is higher than 250 mbar; or having a dew point of lower than 25 C., wherein the partial pressure of component A as measured at 293.15 K is higher than 150 mbar.

8. The dielectric-insulation or arc-extinction fluid according to claim 5, having a dew point of lower than 0 C., wherein the partial pressure of component A as measured at 293.15 K is higher than 900 mbar; or having a dew point of lower than 5 C., wherein the partial pressure of component A as measured at 293.15 K is higher than 750 mbar.

9. The dielectric-insulation or arc-extinction fluid according to claim 5, the total pressure of which being at least 6 bar as measured at 293.15 K.

10. The dielectric-insulation or arc-extinction fluid according to claim 5, being non-ozone depleting and having a Global Warming Potential over a time horizon of 100 years of less than 10.

11. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein the first component A is octafluorobut-1-ene or octafluorobut-2-ene.

12. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein the second component B comprises a carrier gas, which has a boiling point of 60 C. at most.

13. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein the second component B comprises a carrier gas, which itself has a lower dielectric strength than the first component A.

14. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein the second fluid component B comprises a carrier gas selected from the group consisting of: oxygen, nitrogen, carbon dioxide, nitrous oxide, and mixtures thereof.

15. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein the second fluid component B comprises carbon dioxide and/or of nitrogen.

16. The dielectric-insulation or arc-extinction fluid according to claim 15, wherein the second fluid component B further comprises oxygen.

17. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein the second fluid component B comprises a mixture of carbon dioxide and oxygen or of a mixture of nitrogen and oxygen or of a mixture of carbon dioxide and oxygen and nitrogen.

18. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein it comprises as the second fluid component B or as a third fluid component C a further fluorinated organic compound different from the linear octafluorobutene of the first gas component A.

19. The dielectric-insulation or arc-extinction fluid according to claim 18, wherein the further fluorinated organic compound is at least one compound selected from the group consisting of: fluoroethers, fluoroketones, fluoroolefins other than a linear octafluorobutene, fluoronitriles, and mixtures thereof.

20. The dielectric-insulation or arc-extinction fluid according to claim 5, wherein the partial pressure of component A, as measured at 293.15 K is chosen in a range of 800 mbar to 1100 mbar; or in a range of 750 mbar to 950 mbar; or in a range of 250 mbar to 520 mbar; or in a range of 150 mbar to 420 mbar.

21. An apparatus for the generation, the transmission, the distribution and/or the usage of electrical energy, said apparatus comprising: a housing enclosing an insulating space and an electrically conductive part arranged in the insulating space, wherein said insulating space contains a dielectric-insulation or arc-extinction fluid, in particular according to claim 1, said dielectric-insulation or arc-extinction fluid comprising: a) a first gas component A comprising or essentially consisting of a linear octafluorobutene, in mixture with b) a second gas component B different from the first gas component A, and having at operating conditions a pressure higher than 1 bar.

22. The apparatus according to claim 21, being a medium voltage or a high voltage apparatus.

23. The apparatus according to claim 21, wherein the apparatus is a medium voltage apparatus and the pressure of the dielectric-insulation or arc-extinction gas is in a range from 1 bar to 2 bar at operating conditions of the medium voltage apparatus.

24. The apparatus according to claim 21, wherein the apparatus is a high voltage apparatus and the pressure of the dielectric-insulation or arc-extinction gas is higher than 3 bar at operating conditions of the high voltage apparatus.

25. The apparatus according to claim 21, wherein the apparatus is or is part of a: switchgear, or part and/or component thereof, gas-insulated line (GIL), busbar, bushing, cable, gas-insulated cable, cable joint, current transformer, voltage transformer, sensor, humidity sensory, surge arrester, capacitor, inductance, resistor, insulator, air-insulated insulator, a gas-insulated metal-encapsulated insulator, current limiter, high voltage switch, earthing switch, disconnector, combined disconnector and earthing switch, load-break switch, circuit breaker, gas circuit breaker, generator circuit breaker, gas-insulated vacuum circuit breaker, medium voltage switch, ring main unit, recloser, sectionalizer, low voltage switch, and/or any type of gas-insulated switch, transformer, distribution transformer, power transformer, tap changer, transformer bushing, electrical rotating machine, generator, motor, drive, semiconducting device, computing machine, power semiconductor device, power converter, converter station, convertor building, and components and/or combinations of such devices.

26. The apparatus according to claim 21, wherein the rated minimal operating temperature of the apparatus being at least 25 C.

27. The apparatus according to claim 21, wherein the partial pressure of component A as measured at 293.15 K is chosen in a range of 800 mbar to 1100 mbar; or in a range of 750 mbar to 950 mbar; or in a range of 250 mbar to 520 mbar; or in a range of 150 mbar to 420 mbar.

28. The apparatus according to claim 21, wherein the apparatus being designed for an indoor application.

29. The apparatus according to claim 21, wherein at least some of the solid components of the apparatus that are directly exposed to the insulation gas are made of a polymeric material, a metal, a metal alloy, a ceramic and/or a composite thereof.

30. The apparatus according to claim 21, wherein the polymeric material is selected from the group consisting of: silicones, polyolefins, polyethers, polyesters, polyurethanes, polyepoxides, polyamides, polyimides, polyketones, polysulfones, as well as mixtures or combinations thereof.

31. The apparatus according to claim 21, wherein the component is selected from the group consisting of: a coating compound, a sealing compound, an adhesive, an insulating compound, a lubricating compound, a molecular sieve, a binder-free molecular sieve, a desiccant, a binder-free desiccant, a humidity sensing material, as well as mixtures thereof.

32. The apparatus according to claim 21, wherein the sealing compound comprises or consists of EPDM or nitrile-butadiene rubber or butyl rubber.

Description

[0099] The results are summarized in

[0100] FIG. 1 showing the breakdown voltage at two different field conditions, each measured under lightning impulse (LI) and under AC stress (AC), for two dielectric-insulation fluids according to the present invention (at 7 bar) in comparison to SF.sub.6 (at 4.5 bar) and a CO.sub.2/O.sub.2 mixture (at 7 bar).

[0101] According to FIG. 1, a slightly higher breakdown voltage was determined for the uniform field tests using the fluid according to the present invention compared with the one using SF.sub.6, the highest values (of about 230 kV under lightning impulse and of about 210 kV under AC stress) having been determined for the octafluoro-2-butene/N.sub.2 mixture.

[0102] For the particle-like field tests, the highest breakdown voltage was determined for the octafluoro-2-butene/CO.sub.2 mixture, the value being at about 200 kV under lightning impulse and therefore much higher than the respective value determined for SF.sub.6 (being lower than 150 kV).

[0103] Thus, the fluid according to the present invention allows to achieve a breakdown voltage (dielectric withstand or breakdown strength or breakdown field strength or breakdown voltage) at 5 C. at 7 bar, which equals or even surpasses the one measured for 4.5 bar of SF.sub.6. Thus, the same dielectric performance as for SF.sub.6 can be achieved at a pressure which can in most cases be withstood by conventional housing (or encapsulation) walls of the apparatus.

[0104] Throughout this application, medium voltage relates to voltages in the range of 1 kV to 52 kV or 72 kV, and high voltage to voltages above this range. While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may otherwise variously be embodied and practised within the scope of the following claims. Therefore, terms like preferred or in particular or particularly or advantageously, etc. signify optional and exemplary embodiments only.