METHODS FOR DIELECTRICALLY INSULATING ELECTRICAL ACTIVE PARTS

Abstract

The invention concerns methods for dielectrically insulating electrical active parts using certain sulphur fluorides, as well as compositions and apparatus comprising such compounds.

Claims

1. A method for dielectrically insulating an electrical active part wherein the electrical active part is arranged in a gas-tight housing comprising an insulating medium comprising a compound of general formula (I):
SF.sub.(6-n)(OR).sub.n(I) wherein n is 1, 2, 3, 4, or 5; and R is alkyl, alkenyl, alkynyl, aryl, fluorosubstituted alkyl, fluorosubstituted alkenyl, fluorosubstituted alkynyl or fluorosubstituted aryl.

2. The method according to claim 1 wherein n is 1.

3. The method according to claim 1 wherein R is fluorosubstituted alkyl.

4. The method according to claim 3 wherein R is CF.sub.3.

5. The method according to claim 1 wherein the compound is trifluoromethoxy sulphurpentafluoride SF.sub.5(OCF.sub.3).

6. The method according to claim 1 wherein the concentration of the compound of general formula (I) in the insulating medium is at least 1 vol %.

7. A composition comprising at least one compound of general formula (I)
SF.sub.(6-n)(OR).sub.n(I) wherein n is 1, 2, 3, 4, or 5; and R is alkyl, alkenyl, alkynyl, aryl, fluorosubstituted alkyl, fluorosubstituted alkenyl, fluorosubstituted alkynyl or fluorosubstituted aryl and at least one further compound selected from the group consisting of an inert gas, a perfluorinated or partially fluorinated ketone, a perfluorinated or partially fluorinated ether, a perfluorinated or partially fluorinated ester, a perfluorinated or partially fluorinated cyano compound and a hydrocarbon compound.

8. The composition according to claim 7 comprising SF.sub.5(OCF.sub.3) and at least one compound selected from the group consisting of an inert gas, a perfluorinated or partially fluorinated ketone, a perfluorinated or partially fluorinated ether, a perfluorinated or partially fluorinated ester, a perfluorinated or partially fluorinated cyano compound and a hydrocarbon compound.

9. The composition of claim 8 comprising SF.sub.5(OCF.sub.3) and at least one compound selected from the group consisting of air, synthetic air, an air component, N.sub.2, O.sub.2, CO.sub.2, N.sub.2O, He, Ne, Ar, Xe and SF.sub.6.

10. An apparatus for the generation, distribution and/or usage of electrical energy wherein the apparatus comprises an electrical active part arranged in a gas-tight housing, said gas-tight housing containing an insulating medium comprising at least one compound of general formula (I)
SF.sub.(6-n)(OR).sub.n(I) wherein n is 1, 2, 3, 4, or 5; and R is alkyl, alkenyl, alkynyl, aryl, fluorosubstituted alkyl, fluorosubstituted alkenyl, fluorosubstituted alkynyl or fluorosubstituted aryl; or containing an insulating medium comprising the composition according to claim 7.

11. The apparatus of claim 10 wherein the insulating medium comprises SF.sub.5(OCF.sub.3).

12. The apparatus of claim 10 wherein the concentration of the compound of general formula (I) in the insulating medium is at least 1 vol %.

13. (canceled)

14. (canceled)

15. The method according to claim 3 wherein R is perfluorinated alkyl.

16. The method according to claim 6 wherein the concentration of the compound of general formula (I) in the insulating medium is at least 2.5 vol %.

17. The method according to claim 16 wherein the concentration of the compound of general formula (I) in the insulating medium is at least 5 vol %.

18. The composition according to claim 7, wherein the concentration of the compound of general formula (I) in the composition is at least 1 vol %.

19. The composition of claim 9 comprising SF.sub.5(OCF.sub.3) and N.sub.2.

Description

EXAMPLES

Example 1a

Manufacture of SF.SUB.5.(OCF.SUB.3.)

[0048] SF.sub.5(OCF.sub.3) is prepared according to Duncan, L. C.; Cady, G. H., Inorganic Chemistry, 1964, 3(6), pp. 850-852.

Example 1b

Manufacture of the Compositions

[0049] As described in WO98/23363, a homogenous mixture consisting SF.sub.5(OCF.sub.3) and N.sub.2 in a volume ratio 1:4 is manufactured in an apparatus comprising a static mixer and a compressor.

Example 2

Provision of an Earth Cable Containing the Dielectrically Insulating Medium of Example 1

[0050] The composition of example 1b is directly fed into an earth cable for high voltage, until a total pressure of 10 bar (abs) is achieved in the cable.

Example 3

A Switchgear Containing SF.SUB.5.(OCF.SUB.3.) and N.SUB.2 .in a Volume Ratio 1:4

[0051] A switchgear is used which contains a switch surrounded by a gas-tight metal case. The composition of example 1b is passed into the gas tight metal case via a valve until a pressure of 18 bar (abs) is achieved.