Method and facility for filling a gas-insulated electrical apparatus comprising a mixture of (CF3)2CFCN and CO2

Patent metadata

Field	Value
Publication number	US-10770198-B2
Application number	US-201615778538-A
Country	US
Kind code	B2
Filing date	Nov 29, 2016
Priority date	Nov 30, 2015
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A method and a facility for filling a high- or medium-voltage gas-insulated electrical apparatus in which the insulating gas comprises a mixture of heptafluoroisobutyronitrile ((CF3)2CFCN) and carbon dioxide. The method and the facility using a mixture of (CF3)2CFCN and CO2 in pressurised liquid form which is heated to a temperature no lower than the critical temperature of the mixture.

First claim

What is claimed is:

1. A method of filling a closed casing containing at least one electrical component of equipment for a high-or medium-voltage electricity transmission line with a gas mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions, said method comprising:
a) preparing, in a container, a pressurized liquid mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions;
b) heating, in the container, the pressurized liquid mixture prepared in a) until it reaches a temperature that is higher than or equal to the critical temperature of the mixture whereby a gas mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions is obtained; and
c) transferring said gas mixture obtained in b) from the container to the casing via a transfer circuit in which the gas mixture is decompressed and maintained at a temperature that is higher than the liquefaction temperature of heptafluoroisobutyronitrile at its partial pressure in the transfer circuit before it enters the casing to be filled.

2. The method according to claim 1 , wherein heating is performed during b) by a heater member outside the container.

3. The method according to claim 1 , wherein heating is performed during b) by a heater member inside the container.

4. The method according to claim 1 , wherein, during c), the molar ratio between heptafluorobutyronitrile and carbon dioxide in the gas mixture is measured.

5. The method according to claim 1 , wherein, during c), the temperature of the gas mixture in the container is measured.

6. The method according to claim 1 , wherein the heating power during a) is adjusted and/or regulated on the basis of:
a molar ratio between heptafluoroisobutyronitrile and carbon dioxide which is measured during c);
a temperature of the gas mixture in the container which is measured during c); or
a measured temperature of a heater members.

7. The method according to claim 1 , wherein the gas mixture comprising heptafluoroisobutyronitrile and carbon dioxide further comprises oxygen.

8. An installation for filling a closed casing containing at least one electrical component of equipment for a high- or medium-voltage electricity transmission line with a gas mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions, the installation comprising:
a container configured for containing a mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions;
a heater member configured for heating the mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions present in the container in pressurized liquid form until it reaches a temperature that is higher than or equal to the critical temperature of the mixture whereby a gas mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions is obtained; and
a transfer circuit configured for transferring the gas mixture comprising heptafluoroisobutyronitrile and carbon dioxide in predefined proportions from the container to the casing, the transfer circuit fluidly connecting said container with the casing and the transfer circuit having an expansion member configured for reducing the pressure of the gas mixture to a determined value to fill the casing for maintaining the gas mixture at a temperature that is higher than the liquefaction temperature of heptafluoroisobutyronitrile at its partial pressure in the transfer circuit, the filling installation comprising one or more temperature safety features.

9. The filling installation according to claim 8 , wherein the transfer circuit has means configured for measuring the molar ratio between heptafluoroisobutyronitrile and carbon dioxide in the gas mixture.

10. The filling installation according to claim 8 , being wherein the transfer circuit presents a temperature sensor configured for measuring the temperature of the gas mixture in the container.

Assignees

• General Electric Technology Gmbh

Inventors

• Kieffel Yannick
• Biquez François
• Porte Jacques

Classifications

• H01H2033/568

  with overpressure release, e.g. rupture membranes · CPC title

• H01H33/563

  comprising means for monitoring the density of the insulating gas · CPC title

• G05D16/2013

  using throttling means as controlling means · CPC title

• G05D16/20

  characterised by the use of electric means · CPC title

• G05D16/02

  Modifications to reduce the effects of instability, e.g. due to vibrations, friction, abnormal temperature, overloading or imbalance · CPC title