Electrical switching device

Patent metadata

Field	Value
Publication number	US-9899167-B2
Application number	US-201615191287-A
Country	US
Kind code	B2
Filing date	Jun 23, 2016
Priority date	Dec 23, 2013
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

An electrical switching device is filled with a dielectric insulating medium comprising an organofluorine compound, in particular a fluoroether, a fluoroarnine, a fluoroketone or a fluoroolefin, and comprises at least an arcing contact arrangement with a first arcing contact and a mating second arcing contact. At least a first intermediate volume is provided downstream from the first arcing contact, and/or at least a second intermediate volume is provided downstream from the second arcing contact. The intermediate volumes are for intermediate pressure enhancement and exhaust gas jet formation for turbulent convective heat transfer to metal walls of the exhaust system. In embodiments, the first and/or second intermediate volume is delimited by at least one moveable wall arranged transversally to the longitudinal axis and shiftable parallel to it by an actuation device.

First claim

The invention claimed is:

1. Electrical switching device having a longitudinal axis, comprising an arcing volume and at least an arcing contact arrangement with a first arcing contact and a mating second arcing contact, and further comprising an exhaust system with at least one exhaust volume,
wherein for closing and opening the electric switching device at least one of the arcing contacts is movable parallel to the longitudinal axis and cooperates with the other arcing contact,
wherein the electrical switching device comprises a dielectric insulating medium comprising an organofluorine compound selected from a group consisting of: a fluoroether, an oxirane, a fluoroamine, a fluoroketone, a fluoroolefine, a fluoronitrile, and mixtures and decomposition products thereof,
wherein inside the exhaust volume at least one intermediate volume is arranged, enclosed by an intermediate wall, and comprises at least one inlet opening for receiving exhaust gas coming from an arcing region, and comprises at least one outlet opening facing an opposing wall of the exhaust volume, for producing at least one exhaust gas jet and for discharging the exhaust jet and impacting the exhaust jet on the opposing wall, and wherein
the intermediate volume is designed such that at least temporarily during a time period of exhaust gas ejection an intermediate exhaust gas pressure in the intermediate volume exceeds an exhaust gas pressure in its immediately succeeding exhaust volume at least by a pressure ratio larger than 1.1.

2. The electrical switching device according to claim 1 , wherein the impacting causes swirling of the at least one exhaust gas jet, wherein the swirling induces turbulent-gas heat transfer to the opposing wall and reduces a temperature and pressure of the swirling exhaust gas jet.

3. The electrical switching device according to claim 1 , wherein the organofluorine compound is selected from a group consisting of: perfluoroether, hydrofluoroether, perfluoroamine, perfluoroketone, perfluoroolefin, hydrofluoroolefine, perfluoronitrile, and mixtures thereof with a background gas compound selected from a group consisting of: air, air components, nitrogen, oxygen, carbon dioxide, nitrogen oxides.

4. The electrical switching device according to claim 1 , wherein the dielectric insulating medium comprising as the organofluorine compound a fluoroketone having from 4 to 15 carbon atoms, or wherein the fluoronitrile is a perfluoronitrile containing two carbon atoms, three carbon atoms or four carbon atoms.

5. The electrical switching device according to claim 4 , wherein the fluoronitrile is at least one of: a perfluoroacetonitrile, perfluoropropionitrile (C 2 F 5 CN), perfluorobutyronitrile (C 3 F 7 CN), perfluoroisobutyronitrile according to the formula (CF 3 ) 2 CFCN, perfluoro-2-methoxypropanenitrile according to a formula CF 3 CF(OCF 3 )CN.

6. The electrical switching device according to claim 1 , wherein the intermediate volume is designed such that during operation, an exhaust gas pressure is decreasing along a travel path of the exhaust gas from the arcing region through the exhaust system.

7. The electrical switching device according to claim 6 , wherein the at least one guiding-wall section of the travel path is provided with projections that extend transversely to the guiding-wall section out of or into the travel path and are for cooling down the exhaust gas, the projections are macroscopic projections and are arranged in a two-dimensional arrangement or two-dimensional matrix at the guiding-wall section and form a two-dimensional arrangement of vortices in the exhaust gas along the guiding-wall section of the travel path to increase a rate of convective heat transfer from the exhaust gas to the guiding-wall section; and
the projections are negative projections that extend into the guiding-wall section of the travel path; or
the projections are positive projections extending out of the guiding-wall section of the travel path.

8. The electrical switching device according to claim 1 , wherein the intermediate volume is designed such that at least temporarily during a time period of exhaust gas ejection an intermediate exhaust gas pressure in the intermediate volume exceeds a pressure in one or more volumes which are downstream of the intermediate volume in a travel path of an exhaust gas through the exhaust system; or that the intermediate volume is designed such that during operation an exhaust gas pressure in the at least one intermediate volume is increased compared to when the at least one intermediate volume were not present.

9. The electrical switching device according to claim 8 , wherein a hollow exhaust tube is mechanically connected to the first arcing contact at a second end part, and
a first further intermediate volume is arranged outside the first intermediate volume, enclosed by a first further intermediate wall, comprises a first further inlet opening for receiving exhaust gas coming from the first intermediate volume, and comprises at least one first further outlet opening, facing a first further opposing wall, and for producing at least one first further gas jet and for discharging the at least one first further gas jet towards and impacting the at least one first further gas jet on the first further opposing wall, and
the first intermediate volume and/or the first further intermediate volume is or are designed such that at least temporarily during a time period of exhaust gas ejection a first intermediate exhaust gas pressure in the first intermediate volume exceeds a first further intermediate exhaust gas pressure in the first further intermediate volume at least by a first further pressure ratio larger than 1.1.

10. The electrical switching device according to claim 8 , wherein the pressure ratio is chosen as a function of the dielectric insulation medium.

11. The electrical switching device according to claim 8 , wherein the pressure ratio is a critical pressure ration, that is chosen:
in a range of 1.6 to 1.7, when the dielectric insulation medium predominantly contains SF 6 , or
in a range 1.7 to 1.8, when the dielectric insulation medium predominantly or exclusively contains the organofluorine compound in a mixture with a background gas.

12. The electrical switching device according to claim 11 , wherein the pressure ratio is in a range 1.7 to 1.8 when the dielectric insulation medium predominately or exclusively is C5-fluoroketone in a mixture with at least one of: CO 2 , O 2 and N 2.

13. The electrical switching device according to claim 1 , wherein
the exhaust system comprises a first exhaust volume downstream from the arcing volume on a first side of the switching device having the first arcing contact, and inside the first exhaust volume at least one first intermediate volume is arranged, enclosed by a first intermediate wall, comprises a first inlet opening, which is for receiving exhaust gas coming from a hollow exhaust tube fluidly connected to the arcing region, and comprises at least one first outlet opening, facing a first opposing wall, and
the first intermediate volume is designed such that at least temporarily during a time period of exhaust gas ejection a first intermediate exhaust gas pressure in the first intermediate volume exceeds a first exhaust gas pressure in the first exhaust volume at least by a first pressure ratio larger than 1.1.

14. The electrical switching device according to claim 1 , wherein
an exhaust comprises a second exhaust volume downstream from the arcing volume on a second side of the switching device having the second arcing contact, and inside the second exhaust volume at least

Assignees

• Abb Schweiz Ag

Inventors

• Florez Javier Mantilla
• Ye Xiangyang
• Dhotre Mahesh
• Cossalter Oliver
• Grob Stephan

Classifications

• H01H33/70

  Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid · CPC title

• H01B3/56 Primary

  gases · CPC title

• H01H33/22

  Selection of fluids for arc-extinguishing · CPC title

• H01H33/74

  wherein the break is in gas (in air at atmospheric pressure H01H33/73) · CPC title

• H01H33/021 Primary

  Use of solid insulating compounds resistant to the contacting fluid dielectrics and their decomposition products, e.g. to SF6 · CPC title