METHODS FOR DIELECTRICALLY INSULATING ELECTRICAL ACTIVE PARTS

Abstract

The invention concerns methods for dielectrically insulating electrical active parts using certain fluorinated phosphorous-bearing compounds 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 consisting of, consisting essentially of, or comprising a compound of general formula (I):
ZPR.sup.1R.sup.2R.sup.3 (I) wherein Z is =O, =S, (F).sub.2 or a lone electron pair; and R.sup.1, R.sup.2 and R.sup.3 are independently C.sub.nH.sub.mF.sub.(2n+1)m or OC.sub.nH.sub.mF.sub.(2n+1)m, wherein n is 1, 2, 3, 4, or 5 and m is an integer between 0 and 2n.

2. The method according to claim 1 wherein Z is =O.

3. The method according to claim 1 wherein R.sup.1, R.sup.2 and R.sup.3 are independently C.sub.nF.sub.2n+1.

4. The method according to claim 1 wherein the compound is tris(trifluoromethyl)phosphine oxide O=P(CF.sub.3).sub.3.

5. The method according to claim 1 wherein the insulating medium comprises the compound of formula (I) and at least one further compound selected from the group consisting of an inert gas, a perfluorinated ketone partially fluorinated ketone, a perfluorinated ether, partially fluorinated ether, a perfluorinated ester, partially fluorinated ester, a perfluorinated cyano compound, partially fluorinated cyano compound, and a hydrocarbon compound.

6. The method according to claim 5 wherein the at least one compound is an inert gas 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.

7. A composition consisting of, consisting essentially of, or comprising at least one compound of general formula (I)
ZPR.sup.1R.sup.2R.sup.3 (I) wherein Z is =O, =S, (F).sub.2 or a lone pair; and R.sup.1, R.sup.2 and R.sup.3 are independently C.sub.nF.sub.2n+1 or OC.sub.nF.sub.2n+1, wherein n is 1, 2, 3, 4, or 5; and at least one further compound selected from the group consisting of an inert gas, a perfluorinated ketone, partially fluorinated ketone, a perfluorinated ether, partially fluorinated ether, a perfluorinated ester, partially fluorinated ester, a perfluorinated cyano compound, partially fluorinated cyano compound, and a hydrocarbon compound.

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

9. The composition of claim 8 consisting of, consisting essentially of, or comprising O=P(CF.sub.3).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 consisting of, consisting essentially of, or comprising at least one compound of general formula (I)
ZPR.sup.1R.sup.2R.sup.3 (I) wherein Z is =O, =S, (F).sub.2 or a lone pair; and R.sup.1, R.sup.2 and R.sup.3 are independently C.sub.nF.sub.2n+1 or OC.sub.nF.sub.2n+1, wherein n is 1, 2, 3, 4, or 5; or containing an insulating medium consisting of, consisting essentially of, or comprising the composition according to claim 7.

11. The apparatus of claim 10 wherein the insulating medium consists of, consists essentially of, or comprises O=P(CF.sub.3).sub.3.

12. The apparatus of claim 10 wherein the apparatus is a switchgear.

13. The method according to claim 6 wherein the at least one compound is N.sub.2.

14. The composition of claim 9 consisting of, consisting essentially of, or comprising O=P(CF.sub.3).sub.3 and N.sub.2.

Description

EXAMPLES

Example 1a: Manufacture of O=P(CF.SUB.3.).SUB.3

[0045] O=P(CF.sub.3).sub.3was prepared according to Burg, A. D., Journal of the American Chemical Society, 1965, 87(2), pages 238-41.

Example 1b: Manufacture of the Compositions

[0046] As described in WO98/23363, a homogenous mixture consisting O=P(CF.sub.3).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

[0047] 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 O=P(CF.SUB.3.).SUB.3 .and N.SUB.2 .in a Volume Ratio 1:4

[0048] A switchgear is used which contains a switch surrounded by a gas-tight metal case. The composition of example b1 is passed into the gas tight metal case via a valve until a pressure of 18 bar (abs) is achieved.