Method and device for determining an operating parameter of a fluid insulated electrical apparatus

Patent metadata

Field	Value
Publication number	US-9903903-B2
Application number	US-201414304647-A
Country	US
Kind code	B2
Filing date	Jun 13, 2014
Priority date	Dec 13, 2011
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A method for deriving at least one operating parameter of a fluid-insulated electrical apparatus, in particular of gas-insulated switchgear. The operating parameter is dependent on a dielectric breakdown strength of an insulation fluid of the electrical apparatus. The insulation fluid includes at least three components that are assigned to at least a first and a second component group such that at least one component group comprises at least two components. The component groups differ in their weighted average values of the molecular masses of the components in the respective component groups. At least one quantity which is indicative of the concentration of the first component group and of the concentration of the second component group is determined from the insulation fluid, e.g. by measuring one or more measurement variables with one or more sensors. The operating parameter is then derived using the at least one quantity.

First claim

What is claimed is:

1. A method for deriving at least one operating parameter P of a fluid-insulated electrical apparatus, which is a gas-insulated medium or high voltage switchgear or a transformer and which comprises an insulation fluid with at least three components X, Y, and Z with component concentrations c X , c Y , and c Z , and
which derived operating parameter P is dependent on a dielectric breakdown strength E bd of the insulation fluid of the electrical apparatus and defines an operational operating state or a failure state of the electrical apparatus,
the method comprising the method elements of:
measuring by means of at least one sensor a plurality of measurement variables, wherein the measurement variables are indicative of at least a pressure and a temperature of the insulation fluid,
assigning the at least three components X, Y, and Z to at least a first component group A with a group concentration c A and to at least a second component group B with a group concentration c B , wherein at least the first component group A comprises at least two of the components X, Y, and Z or wherein at least the second component group B comprises at least two of the components X, Y, and Z,
wherein the at least three components X, Y, and Z are assigned to the at least two component groups A and B in such a way that a weighted average value M A of a molecular mass of the component or components in the first component group A differs from a weighted average value M B of a molecular mass of the component or components in the second component group B,
deriving the group concentrations c A and c B of the component groups A and B by using the measurement variables and at least one relating equation, which is the same or different for each of the component groups A and B, and
deriving the operating parameter P using the group concentration c A and the group concentration c B ;

the method further comprising at least one additional method element selected from the group consisting of:
increasing at least one of the component concentrations c X c Y and/or c Z of the components X, Y, and/or Z of the insulation fluid by injecting an amount of at least one of the components X, Y, and/or Z from a component reservoir into a compartment of the electrical apparatus,
reducing at least one of the component concentrations c X c Y , and/or c Z of the components X, Y, and/or Z of the insulation fluid,
reducing a concentration of at least one contaminant in the insulation fluid by means of a filter,
at least partially evaporating a condensed amount of at least one of the components X, Y, and/or Z of the insulation fluid by means of a heater, and
condensing an amount of at least one of the components X, Y, and/or Z of the insulation fluid by means of a cooler.

2. The method of claim 1 , wherein an absolute value |M A −M B | of the difference between the weighted average values M A −M B of the molecular masses of the components X, Y, and Z between the first and second component groups A and B is larger than weighted statistical spreads σ M,A and σ M,B of the molecular masses of the components X, Y, and Z within the first and second component groups A and B.

3. The method of claim 2 , wherein the absolute value |M A −M B | of the difference between the weighted average values M A −M B of the molecular masses of the components X, Y, and Z between the first and second component groups A and B is larger than 20 g/mol.

4. The method of any of the claims 2 to 3 , wherein the second component group B comprises at least one of the components from the group consisting of:
sulfur hexafluoride,
partially or fully fluorinated ethers, in particular hydrofluoroethers, hydrofluoro monoethers, hydrofluoro monoethers containing at least 3 carbon atoms, perfluoro monoethers, or perfluoro monoethers containing at least 4 carbon atoms,
partially or fully fluorinated ketones, in particular hydrofluoro monoketones, perfluoro monoketones, perfluoro monoketones comprising at least 5 carbon atoms, or perfluoro monoketones comprising exactly 5 or 6 or 7 or 8 carbon atoms, and
mixtures thereof, and
wherein the first component group A comprises at least one of the components from the group consisting of:
nitrogen,
oxygen,
carbon dioxide,
nitric oxide,
nitrogen dioxide,
nitrous oxide,
argon,
methanes, in particular partially or fully halogenated methanes, in particular tetrafluoromethane or trifluoroiodomethane,
air, in particular technical air or synthetic air, and
mixtures thereof.

5. The method of claim 2 , wherein the absolute value |M A −M B | of the difference between the weighted average values M A −M B of the molecular masses of the components X, Y, and Z between the first and second component groups A and B is larger than 50 g/mol.

6. The method of claim 2 , wherein the absolute value |M A −M B | of the difference between the weighted average values M A −M B of the molecular masses of the components X, Y, and Z between the first and second component groups A and B is larger than 100 g/mol.

7. The method of claim 1 , wherein the at least three components X, Y, and Z are assigned to the at least two component groups A and B in such a way that a weighted average value E crit,A of a critical field strength of the component or components in the first component group A differs from a weighted average value E crit,B of a critical field strength of the component or components in the second component group B.

8. The method of claim 7 , wherein an absolute value |E crit,A −E crit,B | of the difference between the weighted average values E crit,A −E crit,B of the critical field strengths of the components X, Y, and Z between the first and second component groups A and B is larger than weighted statistical spreads σ Ecrit,A and σ Ecrit,B of the critical field strengths of the components X, Y, and Z within the first and second component groups A and B.

9. The method of claim 1 , wherein the second component group B comprises at least one of the components from the group consisting of:
sulfur hexafluoride,
partially or fully fluorinated ethers, in particular hydrofluoroethers, hydrofluoro monoethers, hydrofluoro monoethers containing at least 3 carbon atoms, perfluoro monoethers, or perfluoro monoethers containing at least 4 carbon atoms,
partially or fully fluorinated ketones, in particular hydrofluoro monoketones, perfluoro monoketones, perfluoro monoketones comprising at least 5 carbon atoms, or perfluoro monoketones comprising exactly 5 or 6 or 7 or 8 carbon atoms, and
mixtures thereof, and
wherein the first component group A comprises at least one of the components from the group consisting of:
nitrogen,
oxygen,
carbon dioxide,
nitric oxide,
nitrogen dioxide,
nitrous oxide,
argon,
methanes, in particular partially or fully halogenated methanes, in particular tetrafluoromethane or trifluoroiodomethane,
air, in particular technical air or synthetic air, and
mixtures thereof.

10. The method of claim 9 , wherein the second component group B comprises at least one component from the group consisting of:
cyclic and/or aliphatic fluoropentanones,
cyclic and/or aliphatic fluorohexanones,
cyclic and/or aliphatic fluoroheptanones,
sulfur hexafluoride, and
hydrofluoroethers.

11. A computer program element comprising computer program code means for, when executed by a processing unit, implementing a method according to any one of the claims 1 , 6 and 10 .

12. The method of claim 9 , wherein the first component group A comprises:
the components nitrogen and oxygen with relative partial pressures between p(N 2 )/(p(O 2 )+p(N 2 ))=0.7, p(O 2 )/(p(O

Assignees

• Kramer Axel
• Paul Thomas Alfred
• Mahdizadeh Navid
• Ranjan Nitesh
• Abb Technology Ag

Inventors

• Kramer Axel
• Paul Thomas Alfred
• Mahdizadeh Navid
• Ranjan Nitesh

Classifications

• G01R31/3275

  Fault detection or status indication · CPC title

• H01H2033/566

  Avoiding the use of SF6 · CPC title

• H01H33/563

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

• G01R31/1281 Primary

  of liquids or gases · CPC title

• G01R31/06

  Physics · mapped topic