Method for dielectrically insulating active electric parts

Abstract

A method for dielectrically insulating active electric parts A method for dielectrically insulating an active electric part wherein the electrical active part is arranged in a gas-tight housing comprising an insulating gas which contains or consists of a compound of formula (i) Rf1-(O)x-Rf2 wherein Rf1 and Rf2 are identical or different and designated fluorocarbon residues having a H/F ratio of equal to or less than 0.5 and x is 1, 2, or 3.

Claims

1. A method for dielectrically insulating an electrical active part, the method comprising arranging the electrical active part in a gas-tight housing comprising an insulating gas which contains a compound of formula (I)
Rf1-(O).sub.2Rf2(I) wherein Rf1 and Rf2, which are identical or different, are each independently selected from the group consisting of perfluorinated ethyl, perfluorinated n-propyl and perfluorinated isopropyl.

2. The method of claim 1 wherein the compound of formula (I) has an atmospheric boiling point of less than 20 C.

3. The method of claim 2, wherein the compound of formula (I) has an atmospheric boiling point of equal to or lower than 0 C.

4. The method of claim 1 wherein the insulating gas comprises the compound of formula (I) and an inert gas.

5. The method of claim 4 wherein the inert gas is selected from the group consisting of nitrogen, argon and helium.

6. The method of claim 1 wherein the insulating gas comprises the compound of formula (I) and air or synthetic air.

7. The method of claim 1 wherein the content of compound of formula (I) in the insulating gas is from >1 to 80% by volume.

8. The method of claim 7 wherein the content of compound of formula (I) in the insulating gas is from 5 to 25% by volume.

9. The method of claim 1 wherein the insulating gas further comprises SF6.

10. The method of claim 9 wherein SF6 is in an amount from 0.5% to 20% by volume relative to the volume of the insulating gas.

11. The method of claim 10 wherein SF6 is in an amount from 1% to 10% by volume relative to the volume of the insulating gas.

12. The method of claim 1 wherein the insulating gas is at a pressure from equal to or greater than 0.1 bar (abs.) to equal to or lower than 30 bar (abs).

13. The method of claim 1 wherein the electrical active part is an electrical apparatus or part of an electrical apparatus which is selected from the group consisting of medium and high voltage apparatus.

14. The method of claim 1, wherein the content of compound of formula (I) in the insulating gas is equal to or greater than 1% by volume relative to the volume of the insulating gas.

15. The method of claim 1, wherein the insulating gas consists of the compound of formula (I).

16. A gas mixture comprising a compound of formula (I)
Rf1-(O).sub.2Rf2(I) wherein Rf1 and Rf2, which are identical or different, are fluorocarbon residues having a H/F ratio of equal to or less than 0.5; and air or synthetic air.

17. A dielectric insulating gas comprising the gas mixture of claim 16.

18. A gas mixture comprising a compound of formula (I)
Rf1-(O).sub.2Rf2(I) wherein Rf1 and Rf2, which are identical or different, are each independently selected from the group consisting of perfluorinated ethyl, perfluorinated n-propyl and perfluorinated isopropyl; and an inert gas or air.

Description

EXAMPLE 1

Manufacture of CF3OOCF3

(1) CF.sub.3OOCF.sub.3 is manufactured as described in Example 3 of US-A-2007/0049774.

EXAMPLE 2

Manufacture of Dielectric Insulating Gases

(2) As described in WO98/23363, a homogenous mixture consisting of CF.sub.3OOCF.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 3

Provision of an Earth Cable Containing the Dielectric Insulating Gas of Example 2

(3) The gas mixture of example 2 is directly fed into an earth cable for high voltage, until a total pressure of 10 bar (abs) in the cable is achieved.

EXAMPLE 4

A Switchgear Containing CF3OOCF3 and N2 in a Volume Ratio 1:4

(4) A switchgear is used which contains a switch surrounded by a gas tight metal case. The gas mixture of example 2 is passed into the gas tight metal case via a valve until a pressure of 18 bar (abs) is achieved.

EXAMPLE 5

Provision of a Gas-Insulated Transmission Line Containing the Dielectric Insulating Gas of Example 3

(5) The gas mixture of example 2 is directly fed into an earth cable for high voltage, until a total pressure of 10 bar (abs) in the cable is achieved.