APPARATUS FOR THE GENERATION, DISTRIBUTION AND/OR USAGE OF ELECTRICAL ENERGY AND COMPONENT FOR SUCH AN APPARATUS

Abstract

The present invention relates to an electrical apparatus having an insulating space which contains a dielectric insulation fluid comprising an organofluorine compound. At least one solid component of the apparatus that is directly exposed to the insulation fluid contains a basic body made of a first material and a protective layer made of a second material different from the first material, the protective layer being directly or indirectly applied on the basic body and having a thickness of at least 50 μm. The organofluorine compound is selected from the group consisting of: fluoroethers, fluoroketones, fluoroolefins, fluoronitriles, and mixtures thereof, and the first material comprises or consists of a material selected from the group consisting of: a polymeric material, a ceramic, a composite material, and mixtures or combinations thereof.

Claims

1-38. (canceled)

39. An apparatus for the generation, transmission, distribution and/or usage of electrical energy, the apparatus comprising: a housing enclosing an insulating space and an electrically conductive part arranged in the insulating space, the insulating space containing a dielectric insulation fluid comprising an organofluorine compound, at least one solid component of the apparatus being directly exposed to the insulation fluid, wherein the at least one solid component that is directly exposed to the insulation fluid contains a basic body made of a first material and a protective layer made of a second material different from the first material, the protective layer being directly or indirectly applied on the basic body and having a thickness of at least 50 μm, wherein the organofluorine compound is selected from the group consisting of: fluoroethers, fluoroketones, fluoroolefins, fluoronitriles, and mixtures thereof, and wherein the first material is an insulating material and consists of a material selected from the group consisting of: a polymeric material, a ceramic, a composite material, and mixtures or combinations thereof; and wherein the second material comprises a polymeric material: selected from the group consisting of: epoxy resins, polyurethanes and mixtures thereof, or selected from the group consisting of: polyimide, polypropylene, polystyrene, polycarbonate, polymethyl methacrylate, polysulfone, polyetherimide, polyether ether ketone, aromatic hydrocarbon polymers, fluorinated polymers, silicone, as well as combinations thereof, when the protective layer has a thickness ranging from 1 mm to 10 mm, or selected from the group consisting of: polyimide, polypropylene, polystyrene, aromatic hydrocarbon polymers, fluorinated polymers, polyamide, an ethylene-monochlorotrifluoroethylene copolymer, as well as combinations thereof, when the protective layer has a thickness ranging from 60 μm to 100 μm.

40. The apparatus according to claim 39, wherein the second material is made of dielectric material.

41. The apparatus according to claim 39, wherein the protective layer has a thickness of at least 100 μm.

42. The apparatus according to claim 39, wherein the protective layer has a thickness in the range 50 μm to 100 μm.

43. The apparatus according to claim 39, wherein the polymeric material of the protective layer has a glass transition temperature higher than 100° C.

44. The apparatus according to claim 39, wherein the polymeric material of the protective layer has a crosslinking density in the range from 50% to 100%.

45. The apparatus according to claim 39, wherein the protective layer is applied indirectly onto the basic body, and between the basic body and the protective layer a reinforcement layer is arranged.

46. The apparatus according to claim 39, wherein the protective layer is a lacquer.

47. The apparatus according to claim 39, wherein the solid component has a first side oriented towards the insulation fluid and a second side remote from the first side and not being oriented towards the insulation fluid, the protective layer being applied on the side of the basic body facing the first side of the solid component.

48. The apparatus according to claim 39, wherein on the side remote from the basic body the surface of the protective layer is directly exposed to the insulation fluid.

49. The apparatus according to claim 39, wherein at operational conditions of the apparatus the reactivity of the second material towards the organofluorine compound is lower than the reactivity of the first material towards the organofluorine compound.

50. The apparatus according to claim 39, wherein the second material has no reactivity towards the organofluorine compound or any degradation product thereof at operational conditions of the apparatus; and/or the protective layer is for protecting the basic body from reacting with the insulation fluid.

51. The apparatus according to claim 39, wherein the second material is constituted such that it remains unaltered during exposure to the insulation fluid for a period of more than 1 year at operational conditions of the apparatus.

52. The apparatus according to claim 39, wherein the protective layer is a coating, a lacquer, a painting, or a combination thereof applied on the basic body, and the protective layer forms a non-self-supporting structure.

53. The apparatus according to claim 39, wherein the protective layer is made of dielectric material or semiconductive material or slightly conducting material or metallic material, or forms a multi-layer coating containing a combination of such materials.

54. The apparatus according to claim 39, wherein the organofluorine compound is selected from the group consisting of: hydrofluoroethers, in particular hydrofluoromonoethers, perfluoroethers, perfluoroketones, hydrofluoroolefins, perfluoronitriles, and mixtures thereof.

55. The apparatus according to claim 39, wherein the insulation fluid comprises a fluoroketone containing from four to twelve carbon atoms.

56. The apparatus according to claim 39, wherein the insulation fluid comprises a hydrofluoromonoether containing at least three carbon atoms.

57. The apparatus according to claim 39, wherein the insulation fluid comprises air or at least one air component selected from the group consisting of: oxygen (O.sub.2), nitrogen (N.sub.2), carbon dioxide (CO.sub.2), and mixtures thereof.

58. The apparatus according to claim 39, wherein the insulation fluid comprises carbon dioxide (CO.sub.2) in a mixture with oxygen.

59. The apparatus according to claim 58, wherein the insulation fluid comprises carbon dioxide and oxygen and the ratio of the amount of carbon dioxide to the amount of oxygen ranges from 50:50 to 100:1.

60. The apparatus according to claim 39, wherein the apparatus is part of or is a: high voltage apparatus, medium voltage apparatus, low voltage apparatus, direct-current apparatus, switchgear, air-insulated switchgear, part or component of air-insulated switchgear, gas-insulated metal-encapsulated switchgear (GIS), part or component of gas-insulated metal-encapsulated switchgear, gas-insulated transmission line (GIL), busbar, bushing, gas-insulated cable, cable joint, current transformer, voltage transformer, sensors, humidity sensors, surge arrester, capacitor, inductance, resistor, current limiter, high voltage switch, earthing switch, disconnector, combined disconnector and earthing switch, load-break switch, circuit breaker, gas circuit breaker, gas-insulated vacuum circuit breaker, generator circuit breaker, medium voltage switch, ring main unit, recloser, sectionalizer, low voltage switch, any type of gas-insulated switch, transformer, distribution transformer, power transformer, tap changer, transformer bushing, electrical rotating machine, generator, motor, drive, semiconducting device, power semiconductor device, power converter, converter station, convertor building; and components and/or combinations of such devices.

61. The apparatus according to claim 39, wherein the solid component or its basic body is or are a solid insulator or post insulator or compartment insulator or GIS insulator arranged or for being arranged in a medium-voltage GIS or high-voltage GIS, or is a GIL insulator or transformer insulator for a gas-insulated transformer or a solid insulation in a gas-insulated cable, wherein the protective layer is made of a dielectric material or semiconductive material or slightly conducting material, or forms a multi-layer containing a combination of such materials.

62. The apparatus according to claim 39, wherein the solid component or its basic body is or are a sealing component, wherein the protective layer is made of a semiconductive material or slightly conducting material or metallic material, or forms a multi-layer containing a combination of such materials.

63. A method for preventing reaction of at least one solid component of an apparatus for the generation, transmission, distribution and/or usage of electrical energy, the apparatus comprising a housing enclosing an insulating space and an electrically conductive part arranged in the insulating space, the insulating space containing a dielectric insulation fluid comprising an organofluorine compound, at least one solid component of the apparatus being directly exposed to the insulation fluid, the method comprising the steps of: a) providing a basic body of the at least one solid component, the basic body being made of a first material, and b) applying onto the surface of the basic body a protective layer made of a second material, wherein at operational conditions of the apparatus the reactivity of the second material towards the organofluorine compound is lower than the reactivity of the first material towards the organofluorine compound.

Description

[0086] The present invention is further illustrated by way of the attached figures, of which

[0087] FIG. 1 relates to a schematic illustration of a surface-near region of a solid component according to the present invention in cross-section;

[0088] FIG. 2 relates to the volume concentration of the decomposition product heptafluoropropane in an insulation fluid comprising an organofluorine compound after having subjected the insulation fluid to various solid components in humid or dry conditions for one month at 100° C.; and

[0089] FIG. 3 relates to the volume concentration of the decomposition product hexafluoropropene in an insulation fluid comprising an organofluorine compound after having subjected the insulation fluid to various solid components in humid or dry conditions for one month at 100° C.

[0090] In the apparatus or electrical apparatus according to the present invention, the solid component 2 shown in FIG. 1 is arranged in a manner that it is directly exposed to the insulation fluid 3 contained in the insulation space 4 of the apparatus. In the embodiment shown, the insulation fluid 3 is for example an insulation gas 31. It may also be a liquid.

[0091] The solid component 2 contains a basic body 5 made of a first material. In particular, this material can be any material well-established e.g. for use in an SF.sub.6-insulated apparatus, such as polyamides. In the specific case shown in FIG. 1, the first material is an insulator.

[0092] In the embodiment shown, the solid component 2 has a first side 6 exposed to the insulation fluid and a second side (not shown) remote from the first side and not being exposed to the insulation fluid 31.

[0093] On the side 8 of the basic body 5 facing the first side 6 of the solid component 2, a protective layer 10 is applied which is made of a second material different from the first material. Thus, on the side remote from the basic body 5 the surface of the protective layer 10 is directly exposed to the insulation fluid.

[0094] In the embodiment shown, the protective 10 layer is applied directly on the basic body 5, meaning that there is no intermediate layer formed between the basic body 5 and the protective layer 10. However, it is also thinkable to provide an intermediate layer, such as an adhesion promoter and/or primer, between the basic body 5 and the protective layer 10. In this case, the protective layer is applied indirectly on the basic body 5.

[0095] The second material comprises or consists of a polymeric material selected from the group consisting of: epoxy resins, polyolefins, particularly hydrogenated polyolefins or fluorinated polyolefins and more particularly polytetrafluoroethylene, polyurethanes, and mixtures thereof.

[0096] In embodiments, the protective layer 10 is made of dielectric material. In further embodiments, the protective layer 10 is a coating, a lacquer, a painting, or a combination thereof applied on the basic body 5.

[0097] By preventing the basic body 5 from coming into direct contact with the insulation fluid, the protective layer 10 shields the first material from reaction with the organofluorine compound or any other component of the insulation fluid, such as degradation products of the organofluorine compound. The integrity of both the insulation fluid as well as of the solid component can thus be ensured.

[0098] Among the different polymeric materials mentioned above, epoxy resins are highly preferred, as shown in FIGS. 2 and 3. According to FIGS. 2 and 3, exposure of the different epoxy resin grades to an organofluorine-compound-containing insulation fluid resulted in most cases in almost no generation of decomposition products heptafluoropropane and hexafluoropropene, respectively. In the specific case, C5K in combination with a mixture of technical air (80% N.sub.2 and 20% CO.sub.2) as a carrier gas was used, whereby the ratio of the C5K to the carrier gas varied with the temperature of application and was chosen such to have a maximum partial pressure of C5K, but avoiding condensation in the apparatus.

[0099] Heptafluoropropane and hexafluoropropene are the major decomposition products of the organofluorine compound used and can therefore be used as indicators for the compatibility of the material of the solid component with the insulation fluid. The highest concentrations for both of these decomposition products have been determined for epoxy resin grade 4A-PG-04 N and 4A-PG-04 D. However, the concentration determined for this grade is still far lower than what is determined for conventional sealings and thermoplastics (both containing basic fillers and additives, such as MgO, CaO, NaO, amines and phenols) developed for use in an SF.sub.6-insulated apparatus: whereas—after exposure to an organofluorine compound-containing insulation fluid—these sealings and thermoplastics generate heptafluoropropane in a concentration of more than 4%, the concentration generated by epoxy resin grade 4A-PG-04 is only about 1.8%.

[0100] As mentioned above, the protective layer according to the present invention has a thickness of at least 50 μm. It has been found that by a protective layer of this thickness, gas permeation, in particular of the organofluorine compound, is negligible. Thus, the protective layer prevents the organofluorine compound from permeating to the first material which is potentially reactive towards the organofluorine compound. This has important consequences not only for the dielectric insulation fluid which retains is functionality over a prolonged period, given that the organofluorine compound is not subject to degradation reactions. Also, the solid component or its basic body, which is or are made of a dielectric insulating material, retains its insulation function over a prolonged period, since it is not chemically attacked by the dielectric insulation fluid.

[0101] For example, the typically observed problem of polyamide components becoming extremely brittle when exposed to fluoroketone, which itself undergoes degradation by this exposure, can be circumvented. In comparison to unprotected polyamide components, solid polyamide components according to the present invention being covered with a protective layer do not easily break upon mechanical stress and the dielectric properties of the insulation fluid are maintained over a prolonged period.

[0102] The same applies to a solid component or its basic body comprising or consisting of polyamide or a polyamide composite, to a solid component or its basic body containing alkaline or alkaline earth cations, e.g. to a fiber reinforced composite and/or to an elastomer, e.g. containing MgO or CaO as a filler, since without the protective layer of the present invention, these materials tend all to nucleophilic substitution of e.g. the ketone moiety of the fluoroketone or the nitrile moiety of the fluoronitrile.

[0103] As also mentioned above, the reactivity of the second material towards the organofluorine compound is lower than the reactivity of the first material towards the organofluorine compound at operational conditions of the apparatus. Specifically, the term “reactivity” as used in the context of the present invention relates to the ability or tendency of the material to attack the organofluorine compound or any degradation product at operational conditions, in particular its functional group, more specifically the ketone moiety in the case of the organofluorine compound being or comprising a fluoroketone or the nitrile moiety in the case of the organofluorine compound being or comprising a fluoronitrile. In accordance, the term “inert” or “inertness” relates to an inexistent or negligible tendency of the material to chemically attack the organofluorine compound or any degradation product thereof at operational conditions.

[0104] In the specific case that the material of the protective layer is at least approximately inert towards the insulation fluid at operational conditions of the apparatus, the protective layer has a dual function, firstly to withdraw reactive groups from the surface of the solid component or its basic body, that is directly exposed to the insulation fluid, and secondly to prevent reaction of the organofluorine compound with the first material which would be possible to occur in case the organofluorine compound would permeate through the layer.

[0105] For example, a suitable protective layer is a cured epoxy system comprising a multifunctional epoxy resin, a hardener and an accelerator. In even more specific terms, a cured epoxy system comprising Araldite® CY179 (as multifunctional epoxy resin), Aradur® 917 (as hardener) and Accelerator DY 070 can be used (all available from Huntsman).

[0106] As also mentioned above, the first material, i.e. the material of the solid component or basic body of the at least one solid component, comprises or consists of a material selected from the group consisting of: a polymeric material, a ceramic, a composite material, in particular an insulating composite material, and mixtures or combinations thereof. In other words, the first material is a dielectric insulating material. The present invention is therefore in clear distinction from the teaching of WO 2014/037566 according to which a solid dielectric layer is applied on electrical conductors or electrodes. Accordingly, also the technical problem which the teaching WO 2014/037566 attempts to solve is completely different, namely to provide a hybrid dielectric insulation.

[0107] As further mentioned above, the polymeric material of the protective layer, in particular the epoxy resin, has a glass transition temperature (Tg) higher than 100° C. However, in case the solid component is a sealing, a material having a lower Tg can be preferred, since for the sealing a flexible material of a relatively low Tg is generally preferred.

[0108] According to embodiments of the present invention, the second material has a density higher than 120 kg/m.sup.3, preferably higher than 150 kg/m.sup.3, more preferably higher than 170 kg/m.sup.3, and most preferably higher than 220 kg/m.sup.3. According to this embodiment, the density is thus higher than e.g. the one of an insulating foam to be used in a cable, particularly of the low loss foam disclosed in WO 2004/094526. In fact, in attempting to prevent reaction of the organofluorine compound contained in the dielectric insulation fluid and, to this end, also to provide a low gas permeation to the first material of the basic body, the protective layer according to the present invention is not only in its density but also in its function in clear distinction from the foam of WO 2004/094526, which in addition is not exposed to an organofluorine compound-containing insulation fluid.

[0109] Further, the protective layer of the present invention is in clear distinction from any self-supporting component that is not applied on a basic body, such as the cover according to WO 2014/037395, protecting the cavity of a gas-open measurement cell from particle contamination.

[0110] Throughout this application, all embodiments and hence claims disclosed for the apparatus are applicable, as well, to the solid component of the apparatus, and vice versa. Furthermore, all embodiments of the methods or use also apply to the apparatus and solid component, and vice versa.

LIST OF REFERENCE NUMERALS

[0111] 2 solid component [0112] 3; 31 insulation fluid; insulation gas [0113] 4 insulation space [0114] 5 basic body [0115] 6 first side of the solid component exposed to the insulation fluid [0116] 8 side of the basic body facing the first side of the solid component [0117] 10 protective layer; coating [0118] 12 side of the protective layer remote from the basic body