Gas-insulated apparatus and method for manufacturing the same

Abstract

To provide a technique for imparting heat radiation performance capable of efficiently radiating heat of a conductor in a container to the outside of the container.SOLUTION: A coating film is formed on part of or the whole of a surface of a conductor in a gas-insulated apparatus and a container housing the conductor together with an insulating gas. The coating film contains binder resin and heat radiating filler having an emissivity of 0.7 or more, and content of the heat radiating filler in the coating film is 30% by volume or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to gas insulated equipment and a method for manufacturing the same. [Background technology]

[0002] Gas-insulated equipment is known as equipment installed as substation equipment and power-receiving equipment for the purpose of ensuring a stable supply of electric power. Gas-insulated equipment includes circuit breakers, disconnecting switches, and grounding devices, which are hermetically housed in metal containers filled with a gas with high insulating properties. One issue with gas-insulated equipment is how to deal with heat generation when a large current flows through conductors in facility equipment and other devices. A known example of such gas-insulated equipment that includes a heat generation countermeasure is a configuration in which insulating gas, filled at a predetermined pressure in a container that houses conductors that make up an electric circuit, is sent through a circulation flow path to a cooler outside the container, where it is cooled by the cooler and then returned to the container (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-220496 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional techniques have problems such as the device becoming large, the installation location being limited, or the overall structure including the gas cooling means becoming complicated or large.

[0005] As described above, further improvements are required for gas-insulated equipment, from the viewpoint of enabling the heat of the conductors inside the container to be efficiently dissipated to the outside of the container even when a large current is passed through it, and of taking measures to deal with heat generation without increasing the size of the entire device.

[0006] An object of one aspect of the present invention is to provide a technology for imparting heat dissipation performance that enables heat from a conductor inside a container to be efficiently released to the outside of the container. [Means for solving the problem]

[0007] In order to solve the above problems, one embodiment of the present invention provides a gas-insulated device comprising a conductor that constitutes an electric circuit, a container that houses the conductor and into which an insulating gas is pressurized, and a coating that is formed on part or all of the surface of one or both of the conductor and the container, wherein the coating is composed of a binder resin and a filler, the filler includes a thermally emissive filler having an emissivity of 0.7 or more, and the content of the thermally emissive filler in the coating is 30% by volume or more.

[0008] In order to solve the above-mentioned problems, a method for manufacturing gas-insulated equipment according to one embodiment of the present invention includes a step of applying a coating paint to part or all of the surface of one or both of a conductor constituting an electric circuit in the gas-insulated equipment and a container that houses the conductor and into which an insulating gas is pressurized, and the coating paint contains 30% by mass or more of a coating component that includes a thermally emissive filler having an emissivity of 0.7 or more. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to provide a technology for imparting heat dissipation performance that enables heat from a conductor inside a container to be efficiently released to the outside of the container. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram schematically illustrating a configuration of a gas-insulated device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining the arrangement of a coating according to one embodiment of the present invention. [Figure 3] FIG. 1 is a diagram schematically illustrating a configuration of a coating according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating the structure of a sample for a heat dissipation test in an example. [Figure 5] FIG. 2 is a diagram schematically illustrating the configuration of an apparatus for a heat dissipation test in the examples. [Figure 6] FIG. 10 is a diagram for explaining the arrangement of samples in a heat dissipation test in the examples. [Figure 7] FIG. 10 is a graph showing the change in surface temperature with respect to the heating time in a heat dissipation test in an example. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Gas insulated equipment] A gas insulated equipment according to an embodiment of the present invention includes a conductor that constitutes an electric circuit, a container that houses the conductor and into which an insulating gas is pressurized, and further includes a coating, which will be described later. First, the gas insulated equipment to which the coating should be applied will be described.

[0012] Gas-insulated equipment generally refers to electrical equipment in which a conductor serving as a heat source is housed in a container filled with insulating gas. Gas-insulated equipment is not limited by its size or the amount of heat generated. Furthermore, gas-insulated equipment is not limited by the behavior of the insulating gas, as long as the effects of the present embodiment described below are achieved. For example, in gas-insulated equipment, the insulating gas may simply be sealed in a container at a specific positive pressure, or may flow within the container. Examples of gas-insulated equipment include gas-insulated switchgear and gas-insulated busbars.

[0013] Conductors in gas-insulated equipment constitute an electric circuit and typically generate heat when electricity is passed through them. The conductors may be various electrical devices that generate heat when electricity is passed through them in the gas-insulated equipment, the containers that house them, or parts of them.

[0014] The container of the gas-insulated equipment accommodates the conductor in an airtight state. From the viewpoints of mechanical strength and thermal conductivity, the container is preferably made of a metal such as aluminum, copper, iron, or stainless steel.

[0015] The insulating gas in the gas-insulated equipment may be any gas known to be used in that application. Examples of insulating gases include sulfur hexafluoride (SF6) gas, nitrogen gas, carbon dioxide gas, and dry air.

[0016] It is preferable that the surface of the gas insulated equipment that is covered with a coating (described later) is roughened in order to improve adhesion of the coating to the surface, which further improves the efficiency of heat conduction from the surface to the coating.

[0017] The degree of roughening of the surface can be determined as appropriate within a range that achieves the aforementioned effect of improving adhesion. From the viewpoint of expecting the aforementioned effect of improving adhesion, the surface roughness of the roughened surface is preferably about the same as the particle size of the thermally emissive filler described below, and is preferably, for example, 1 to 10 μm in terms of maximum height roughness Rz. Furthermore, from the viewpoint of the surface smoothness of the coating film to be formed, the surface roughness Rz of the roughened surface is preferably smaller than the film thickness of the coating film described below. From this viewpoint, the surface roughness Rz is preferably smaller than the minimum value of the film thickness described below, and therefore is preferably 10 μm or less.

[0018] [Coating] The coating in this embodiment is formed on part or all of the surface of one or both of the conductor and the container. The coating may be formed on parts other than the conductor and the container as long as the effects of the present invention are obtained. For example, gas-insulated equipment usually includes insulating parts. The coating may be disposed on a part of the surface of such insulating parts as long as the function of the insulating parts (insulation within the gas-insulated equipment) is fully exhibited.

[0019] If the coating thickness is too thick, the path of heat conduction within the coating becomes long, and the thermal conductivity of the coating may become insufficient. From the viewpoint of sufficiently increasing the thermal conductivity of the coating, the coating thickness is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. If the coating thickness is too thin, the coating paint described below will be required to have high coatability, which may limit the application method and the coating position. Furthermore, the smoothness of the coating surface may be insufficient, which may affect the appearance of the coating or the sealing performance of the container. From the viewpoint of easily producing the coating and sufficiently increasing the smoothness, the coating thickness may be 10 μm or more, or may be 20 μm or more.

[0020] The coating is composed of a binder resin and a filler, and the filler includes a thermally emissive filler. The coating is composed of a continuous phase of the binder resin, and fillers including the thermally emissive filler are dispersed as a dispersion system in the coating. Hereinafter, in this specification, the above-mentioned filler as a dispersion system is also referred to as "total filler," which collectively refers to the thermally emissive filler and other fillers.

[0021] <Binder resin> The binder resin may be any resin known to be used in coating films. One or more types of binder resin may be used. Examples of binder resins include epoxy resins, alkyd resins, silicone resins, acrylic resins, urethane resins, fluororesins, polyester resins, and melamine resins.

[0022] <Filler> The filler may include a thermally emissive filler and other fillers. Examples of other fillers include inorganic fillers other than the thermally emissive fillers described below. Examples of such inorganic filler materials include iron oxide, titanium oxide, silica, alumina, talc, kaolin, and wollastonite.

[0023] From the viewpoint of fully realizing the adhesiveness of the coating, the total filler content in the coating is preferably 80% by volume or less, more preferably 70% by volume or less, and even more preferably 60% by volume or less. On the other hand, from the viewpoint of enhancing the thermal conductivity of the coating, it is most preferable that the total filler content in the coating be the amount that results in the closest packing. From this viewpoint, the total filler content in the coating is preferably 70 to 80% by volume.

[0024] <Thermal radiation filler> The thermally emissive filler is contained in the filler described above and has a specific emissivity and is used in a specific amount ratio in this embodiment. The higher the thermal conductivity of the thermally emissive filler, the better the thermal conductivity between the thermally emissive fillers in the coating, making it easier to transfer heat to the surface of the coating. As a result, the heat dissipation performance of the coating is improved. Furthermore, the emissivity of resins such as binder resins is typically approximately 0.6 to 0.8. Therefore, it is preferable that the thermally emissive filler have an emissivity substantially equal to or higher than that of the binder resin. From this perspective, the emissivity of the thermally emissive filler is preferably 0.7 or higher, more preferably 0.8 or higher. The emissivity of the thermally emissive filler is defined in the far-infrared region, for example, at a wavelength arbitrarily selected from the 4.5 to 15.4 μm wavelength range. For the reasons described above, the higher the emissivity of the thermally emissive filler, the better. The upper limit can be appropriately determined based on other factors, such as availability.

[0025] In addition, since the thermally emissive filler is disposed so that the coating covers the surface of the conductor, it is preferable that the filler has insulating properties in order to fully exhibit the desired electrical function of the conductor. From the above viewpoint, the insulating properties of the thermally emissive filler are, for example, 10 14 It is preferably Ω / cm or more.

[0026] If the content of the thermally emissive filler in the coating is too low, the thermal conductivity of the coating may be insufficient, while if it is too high, the amount of binder resin may be relatively insufficient, which may reduce the adhesion of the coating. From the viewpoint of sufficiently increasing the thermal conductivity of the coating, the content of the thermally emissive filler in the coating is preferably 30% by volume or more, more preferably 40% by volume or more, and even more preferably 50% by volume or more. When the coating contains 30% by volume or more of the thermally emissive filler, the thermally emissive filler is more likely to be exposed on the surface of the coating, making it possible to fully exhibit the thermal emissivity of the thermally emissive filler.

[0027] If the particle size of the thermally emissive filler is too small, the contact between the thermally emissive fillers in the coating increases, increasing the number of contact points between the thermally emissive fillers, which increases the resistance to heat conduction between the thermally emissive fillers and may reduce the efficiency of heat conduction within the coating. If the particle size of the thermally emissive filler is too large, the coatability of the coating material in the manufacturing method described below may decrease, and the application method may be limited. From the viewpoint of sufficiently increasing the efficiency of heat conduction within the coating, the particle size of the thermally emissive filler is preferably 0.1 μm or more, and more preferably 1 μm or more. Furthermore, from the viewpoint of improving the coatability when used in the above-mentioned coating material, the particle size of the thermally emissive filler is preferably 10 μm or less.

[0028] The particle size of the thermally emissive filler may be a representative value indicating the particle size of the thermally emissive filler, and may be the median diameter D50 measured by particle size distribution analysis using laser diffraction. The size of each particle in this measurement may be determined appropriately depending on the particle shape of the thermally emissive filler, and may be, for example, the major axis (maximum diameter) or the equivalent circle diameter. For example, if the thermally emissive filler is irregular in shape, the particle size of the thermally emissive filler may be an approximate diameter. Furthermore, if the particle shape of the thermally emissive filler is scaly, the particle size of the thermally emissive filler may be the length of the long side. The particle size of the thermally emissive filler may be a measured value or a catalog value.

[0029] The thermally emissive filler may be either an organic filler or an inorganic filler as long as it exhibits the above-mentioned emissivity. The material of the thermally emissive filler may be any material that can exhibit the above-mentioned emissivity in a filler state, and the material of the thermally emissive filler is preferably an inorganic filler from the viewpoint of also having other suitable properties such as heat resistance and insulating properties. One or more inorganic fillers may be used, and examples thereof include aluminum nitride, boron nitride, silicon carbide, carbon, alumina, and silica.

[0030] The emissivity of the thermally emissive filler may be a literature value such as a catalog value, or may be measured by a known method for determining the emissivity of a filler. In the present invention, when the coating contains multiple types of fillers as the total filler, all fillers with an emissivity of 0.7 or more are thermally emissive fillers, and fillers of the same type but with an emissivity of less than 0.7 are other fillers.

[0031] [Method for manufacturing gas-insulated equipment] The gas insulated equipment according to the embodiment of the present invention can be manufactured by a method including a coating step of applying a coating paint to part or all of the surfaces of one or both of the conductor and the container in the gas insulated equipment having the conductor and the container. The coating paint is a paint for forming the coating described above, and is a paint that becomes the coating by curing or solidifying the coating film of the coating.

[0032] The above-mentioned coating step can be carried out by a known coating technique according to conditions related to coating, such as the properties of the coating material and the application location (the position on the gas-insulated equipment where the coating is to be formed), etc. For example, the coating step may be spray coating, or application with a brush or roller.

[0033] It is preferable that the coating paint has sufficient fluidity and viscosity in order to achieve sufficient application properties of the coating paint. For example, if the coating paint contains too much liquid component such as thinner, it may be difficult to mix uniformly and the solid components may be more likely to separate. From the viewpoint of maintaining sufficient heat dissipation and uniform stability as well as realizing appropriate fluidity and viscosity as a coating paint, it is preferable to use a coating paint containing 30% by mass or more of coating components including a thermally emissive filler, and it is more preferable to use a coating paint containing 40% by mass or more of coating components including a thermally emissive filler.

[0034] The term "coating component" refers to a component that constitutes the coating as a solid when it is formed into a coating. For example, the thermally emissive filler and the aforementioned binder resin are coating components. Other solid components contained in the coating paint, such as fillers other than the thermally emissive filler or curing agent components that harden the binder resin, are also coating components. From the viewpoint of the above-mentioned coatability and thermal conductivity of the coating film, the content of the coating component in the coating paint is more preferably 60% by mass or more, and even more preferably 70% by mass or more. The content of the coating component in the coating paint may be within a range that allows a coating to be formed from the paint, and may be, for example, 90% by mass or less.

[0035] The manufacturing method may further include other steps in addition to the above-described coating step, as long as the above-described effects of this embodiment can be obtained. For example, the manufacturing method according to this embodiment may further include a step of preparing a coating paint prior to the coating step. The coating paint can be prepared by mixing a base paint with a thermally emissive filler. The base paint may be any paint containing the above-described binder resin. Such a base paint may be any paint that can be applied to the portion of the gas insulated equipment where a coating is to be formed. The base paint may be a manufactured product or a commercially available product.

[0036] [Specific embodiment] [composition] A specific example of a gas-insulated equipment according to an embodiment of the present invention will be described below, taking as an example a reduced-size gas-insulated switchgear manufactured by Nissin Electric Co., Ltd. to which the coating of this embodiment is applied. The configuration of the gas-insulated equipment according to an embodiment of the present invention is schematically shown in Fig. 1. As shown in Fig. 1, the gas-insulated equipment 1 includes a gas circuit breaker 3, a lightning arrester 4, a voltage transformer 5, a disconnecting switch 6, a cable connection section 7, a grounding switch 8, a current transformer 9, and a simplified disconnecting device 10, housed within a metal container 2. Within the container 2, insulating partition walls 11 arranged at appropriate locations form a plurality of independent spaces.

[0037] In Figure 1, the diagonal lines sloping upward to the right indicate the grounding parts for grounding the container 2 and various devices, all of which are made of metal. The diagonal lines sloping upward to the left are live parts, where electricity flows and the heat generated as a result. These live parts correspond to the conductors mentioned above. The highlighted parts are insulating parts made of insulators.

[0038] SF6 gas, which is an insulating gas, is pressurized into the container 2. The SF6 gas is pressurized into each of the spaces separated by the partition walls 11 in the container 2, filling the spaces.

[0039] The entire surface of the live part is covered with a coating 20 as shown in Figure 2. The entire surfaces of the container 2 and the ground part are also covered with the coating 20. In the container 2, both the inner and outer surfaces are covered with the coating 20. The coating 20 is formed, for example, by applying a coating paint containing the material of the coating 20 to the metal parts (the container 2, the ground part, and the live part) of an existing gas insulated device by a known method such as brushing, and then drying to harden the coating.

[0040] As shown in Figure 3, the coating 20 is composed of a matrix phase 21 and a dispersed thermally emissive filler 22. The matrix phase 21 is mainly composed of a binder resin such as an epoxy resin, and may contain other components as long as the effects of the present invention are achieved, as described above. The thermally emissive filler 22 is, for example, the aluminum nitride described above, and is dispersed in the matrix phase 21. The thermally emissive filler 22 is dispersed appropriately in the coating 20 in an amount sufficient to form a heat conduction path in the thickness direction of the coating 20.

[0041] [Explanation of heat dissipation] Heat generated from conductors such as live parts is transferred to the coating 20 by thermal conduction within the container 2, as indicated by the arrows in region A in FIG. 3 . Because the thermally emissive filler 22 typically has a higher thermal conductivity than the matrix phase 21, the heat transferred to the coating 20 is transferred preferentially to the thermally emissive filler 22 rather than to the matrix phase 21. The heat then traverses the thickness of the coating 20 by thermal conduction through the thermally emissive filler 22, for example, via a thermal conduction path indicated by the arrows in region B in FIG. 3 . Then, as indicated by the arrows in region C in FIG. 3 , the heat transferred to the surface of the coating 20 is released by thermal radiation from the surface of the coating 20. Thus, the heat generated in the conductor is transferred by radiation from the surface of the coating 20 to the opposing part of the container 2. Because the thermally emissive filler 22 has an appropriate particle size and is blended in an appropriate amount in the coating 20, a thermal conduction path is formed throughout the entire coating 20 in the thickness direction of the coating 20.

[0042] Furthermore, when the coating 20 receives heat radiation from the coating 20 located opposite, the heat received by radiation is transferred to the container 2 through a heat conduction path within this coating 20. In this case, heat is conducted in the direction opposite to the arrow in Figure 3. That is, the heat transferred to the coating 20 by radiation is transferred to the container 2 through a heat conduction path provided by the thermally emissive filler 22. In this way, the heat transferred to the surface of the coating 20 by radiation is absorbed by the container 2.

[0043] In this way, heat is conducted within the conductor on which the coating 20 is disposed and within the coating 20, and is transmitted by radiation to the area separated by a space from the surface of the coating 20. The heat that has been transmitted to the coating 20 covering the outer wall of the container 2 is conducted within the coating 20 and is radiated from the surface of the coating 20 to the outside of the container 2. In this way, in the gas insulated equipment 1, by appropriately arranging the coating 20 as described above, the heat of the conductor inside the container 2 can be efficiently released to the outside of the container 2.

[0044] The greater the content of the thermally emissive filler 22 in the coating 20, the easier it is to form a path for heat conduction. Also, the larger the particle size of the thermally emissive filler 22, the fewer the number of contacts between the thermally emissive fillers 22. Therefore, the resistance to heat conduction between the thermally emissive fillers 22 can be reduced.

[0045] Furthermore, the radiation of heat from the coating 20 as described above does not require heat conduction to the insulating gas pressurized in the container 2 or convection of the gas. Therefore, the above embodiment is applicable to gas-insulated equipment in which a sufficient cooling effect due to convection of the insulating gas cannot be expected, and the above-described cooling effect can be sufficiently obtained.

[0046] Furthermore, in gas-insulated equipment that removes heat by convection of insulating gas within a container, foreign matter present within the container is likely to fly up due to convection and come into contact with conductors, and malfunctions (dielectric breakdown) due to such contact are likely to occur. In contrast, in the above-described embodiment, since the insulating gas is sealed under pressure within the container 2, even if the insulating gas naturally convects, the flow is sufficiently slow, and foreign matter present within the container is unlikely to fly up, making it difficult for the foreign matter to come into contact with the conductors. Therefore, the probability of malfunctions (dielectric breakdown) due to such contact can be reduced.

[0047] 〔summary〕 In gas-insulated equipment, as described in the background art, a cooler is used to cool the insulating gas heated by the heat of the conductor. This cooler constantly cools the insulating gas in the container housing the conductor, thereby removing heat from the conductor. However, as described above, adding such a cooler to gas-insulated equipment with a complex configuration can be difficult. Furthermore, adding a cooler increases the size of the gas-insulated equipment itself, limiting the space available for installation. Furthermore, as described above, convection of the insulating gas in the container increases the likelihood of foreign matter adhering to the conductor due to the convection, thereby increasing the likelihood of dielectric breakdown.

[0048] In an embodiment of the present invention, a coating containing 30% by volume or more of a thermally emissive filler with an emissivity of 0.7 or more in a binder resin is formed on at least one of the surfaces of the conductor and the container, thereby enabling the heat of the conductor to be effectively transferred to the container by thermal radiation and released to the outside.

[0049] According to the embodiment of the present invention, it is possible to provide additional heat radiation performance to gas-insulated equipment without increasing the size of the gas-insulated equipment.

[0050] In addition, in the embodiment of the present invention, such additional heat radiation performance can be imparted by a coating that can be formed by applying paint to appropriate locations on the gas-insulated equipment, which makes it possible to apply the present invention to parts of gas-insulated equipment with complex shapes, and is therefore highly versatile.

[0051] As is clear from the above description, a first aspect of the present invention is a gas insulated device comprising a conductor that constitutes an electric circuit, a container that houses the conductor and into which an insulating gas is pressurized, and a coating formed on part or all of the surface of one or both of the conductor and the container, the coating being composed of a binder resin and a filler, the filler including a thermally emissive filler having an emissivity of 0.7 or more, and the content of the thermally emissive filler in the coating being 30% by volume or more. According to the first aspect, it is possible to impart heat dissipation performance that enables the heat of the conductor inside the container to be efficiently released to the outside of the container.

[0052] A second aspect of the present invention is the first aspect, wherein the total filler content in the coating is 80% by volume or less. The second aspect is even more effective from the viewpoint of improving the heat conduction efficiency and adhesion of the coating.

[0053] A third aspect of the present invention is the first or second aspect, wherein the particle size of the thermally emissive filler is 0.1 to 10 μm. The third aspect is even more effective from the viewpoint of sufficiently increasing the efficiency of heat conduction within the coating and from the viewpoint of improving the coatability of the coating material.

[0054] A fourth aspect of the present invention is the first to third aspects, wherein the thermally emissive filler is an inorganic filler. The fourth aspect is even more effective from the viewpoint of further imparting desired properties other than thermal emissivity to the thermally emissive filler.

[0055] A fifth aspect of the present invention is any one of the first to fourth aspects, wherein the coating has a thickness of 200 μm or less. The fifth aspect is even more effective from the viewpoint of sufficiently increasing the heat conduction efficiency of the coating.

[0056] A sixth aspect of the present invention is any one of the first to fifth aspects, wherein the surface of one or both of the conductor and the container is roughened at a portion covered with the coating, which is even more effective from the viewpoint of enhancing adhesion of the coating to the surface.

[0057] A seventh aspect of the present invention is a method for producing gas insulated equipment, comprising the step of applying a coating material to part or all of the surface of one or both of a conductor constituting an electric circuit in the gas insulated equipment and a container that houses the conductor and is filled with an insulating gas, the coating material containing 30 mass % or more of a coating component that includes a thermally emissive filler having an emissivity of 0.7 or more. According to the seventh aspect, as in the first aspect, it is possible to impart heat dissipation performance that enables the heat of the conductor inside the container to be efficiently released outside the container. Furthermore, according to the seventh aspect, the coating material has good applicability.

[0058] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Example]

[0059] An embodiment of the present invention will be described below.

[0060] [Coating paint] [Preparing base paint, etc.] Base paint 1, base paint 2, hardener, and thinner were prepared, each containing the components shown in Table 1 in the amounts shown below. The "solvent and dispersant components" in Table 1 are thought to volatilize when the paint film hardens. Table 2 shows the calculated volume ratios of resin, hardener, and filler when the film is formed.

[0061] [Table 1]

[0062] [Table 2]

[0063] [Preparation of thermally emissive filler] Fillers 1 and 2 shown in Table 3 were prepared as thermally emissive fillers. The physical properties of Fillers 1 and 2 are shown in Table 3. The particle size (D50) in the table is a catalog value. The emissivity in the table is a value determined in accordance with Japanese Industrial Standards (JIS) R1693-2, and more specifically, it is a value determined by measuring the reflectance spectrum at room temperature using infrared emissivity measurement by Fourier transform infrared spectroscopy (FT-IR), and calculating the total emissivity at 100°C from the obtained data. The specific conditions for measuring the emissivity are shown below. The physical properties of the type of thermally emissive filler (aluminum nitride (AlN)) are shown in Table 4. <Device> FT-IR instrument (Perkin Elmer System 2000) <Measurement conditions> Measurement area: 370~7800cm -1 Accumulation count: 200 times Resolution: 16cm -1 <Sample> The case, with internal dimensions of 33.4 x 33.4 x 3.4 mm, was filled with filler and molded.

[0064] [Table 3]

[0065] [Table 4]

[0066] [Coating paint preparation example 1] The base paint, hardener, thinner and filler were mixed in the amounts shown in Table 5 to prepare coating paints 1 to 8.

[0067] [Coating production example 1] Each coating of coating paints 1 to 8 was applied to a conductive aluminum plate at a target thickness of 200 to 300 μm using a desktop coater (automatic coating device PI-1210 manufactured by Tester Sangyo Co., Ltd.), and the formed coating was heated, cured, and dried to obtain coatings 1 to 8.

[0068] [Adhesion test] Furthermore, the adhesion between the coatings 1 to 8 and the aluminum plate was evaluated by a cross-cut test. The cross-cut test was performed in accordance with JIS K5600-5-6 (ISO2409). 11 cuts were made at 1 mm intervals. After peeling off the adhesive tape, the state of the coating was classified as 0 to 5.

[0069] Table 5 shows the compositions of Coating Paints 1 to 8, the coating components and filler loading ratios, and the results of adhesion tests for Coatings 1 to 8.

[0070] [Table 5]

[0071] The values ​​in Table 5 are calculated assuming the specific gravity of aluminum nitride to be 3.3. The "total filler content" value in Table 5 is the volume percentage (volume %) of all fillers, including the thermally emissive filler and other (inorganic) fillers contained in the base paint, that make up the paint film. The "coating film components" value is the mass percentage (mass %) of the components in the paint that become solids when the paint film is formed. If the adhesion is between 0 and 1, it is considered that there will be no practical problems if the coating is used in gas-insulated equipment.

[0072] <Consideration> The viscosity of coating paint varies depending on the particle shape, particle size, and loading of the thermally emissive filler, as well as whether or not the surface has been treated. High viscosity paints require a larger amount of thinner to reduce the viscosity to a level that can be used as a paint. When the components are mixed in the amounts shown in Table 5, if the coating component is less than 40% by mass, the thinner and other solvent / dispersant components in the paint may appear to separate. This tendency is more pronounced when the coating component is less than 30% by mass.

[0073] From the above, it is considered preferable that the coating composition of the coating material for the coating be 30% by mass or more from the viewpoint of handling as a coating material and film formation, and more preferable that the coating composition be 40% by mass or more. For example, in this case, it is preferable from the viewpoint of forming a coating film by brush application. However, it is fully possible to form a coating film if the coating is applied with a tabletop coater. Therefore, when producing a coating, it is preferable to form the coating film using a method that suits the viscosity of the coating material for the coating (for example, the balance between the solvent / dispersant components and the coating composition).

[0074] If the viscosity of the coating paint can be reduced without reducing the coating component content to less than 40% by mass, the total filler content in the coating paint can be increased. For example, aluminum nitride can be filled at even higher loadings, and Filler 1 in particular is surface-treated aluminum nitride particles, so the total filler content can be increased to 90% by volume or more. For Filler 2, it is preferable that the total filler content in the coating paint be 75% by volume or less, from the perspective of handling the coating paint as described above.

[0075] On the other hand, from the viewpoint of the adhesion of the coating, the adhesion of the coating is good when the total filler content is up to 80% by volume, but when it exceeds 80% by volume, the adhesion tends to decrease. This is thought to be because the content of the binder resin in the coating is too low.

[0076] From the above, it can be seen that the total filler content that can be blended into coating paint varies depending on the type of thermal emissive filler, but from the viewpoint of the adhesion of the produced coating, it is up to about 80% by volume.

[0077] [Coating paint preparation example 2] Coating paints 9 to 13, each with a thermally emissive filler loading of 0 to approximately 50% by volume, were prepared by mixing the components shown in Table 6 in the amounts shown in Table 6 in the same manner as for coating paints 1 to 8 described above. The compositions of coating paints 9 to 13 are shown in Table 6. The "total filler content" value in Table 6 is the volume percentage (volume %) of all fillers in the coating paint (thermally emissive filler and iron oxide or titanium oxide), as in Table 5. This value was calculated based on the volume value of each coating component, which was determined from the number of parts by mass and blended amount of the coating components in the paint and the specific gravity of each component, assuming the specific gravity of aluminum nitride to be 3.3.

[0078] [Table 6]

[0079] [Coating production example 2] Each of the coating paints 9 to 13 was applied to a PTFE (polytetrafluoroethylene) sheet using a desktop coater to a target film thickness of 200 μm, and the formed coating was heated, cured, and dried to obtain coatings 9 to 13. Then, coatings 9 to 13 were peeled off from the PTFE sheet and cut into 20 mm x 20 mm pieces.

[0080] [Thermal conductivity test] The thermal conductivity of each of the coatings 9 to 13 was measured by the temperature gradient method in accordance with JIS H7903. The measurement temperatures were 23°C (room temperature) (heater temperature 42°C / chiller temperature 12°C) and 120°C (heater temperature 200°C / chiller temperature 20°C). The measurement load was 400N, the test piece was a flat plate measuring approximately 20mm x 20mm, and the number of samples was 1. The measurement device used was a thermal conductivity measuring device "TCM-1001" (manufactured by Rhesca Corporation). The thermal conductivity measurement results are shown in Table 7.

[0081] [Table 7]

[0082] <Consideration> The thermal conductivity of coatings 10 and 11 was higher than that of coating 9, which was made only from the base paint, and the thermal conductivity of coating 13 was higher than that of coating 12, which was also made only from the base paint.

[0083] Coatings 10, 11, and 13 exhibited different thermal conductivities depending on the type of thermally emissive filler. For example, the thermal conductivity of Coating 10, which was produced using Filler 1, was 2.2 times that of Coating 9 at 23°C and 2.4 times that at 120°C. The thermal conductivity of Coating 13, which was produced using Filler 1, was 2.3 times that of Coating 12 at 23°C and 2.4 times that at 120°C.

[0084] Furthermore, the thermal conductivity of the coating 11 produced using the filler 2 was 1.1 times that of the coating 9 at 23°C and 1.6 times at 120°C.

[0085] The difference in thermal conductivity between different types is thought to be due to the affinity with the epoxy resin, which is affected by the particle size of the filler or the presence or absence of surface treatment, or the tendency of the thermally emissive filler to aggregate.In addition, it is thought that the paint containing Filler 1 has relatively good fluidity, forming a coating in which the thermally emissive filler is more dispersed.

[0086] [Coating paint preparation example 3] Coating paints 21 and 22 were prepared using Shinto NV and aluminum nitride. The compositions of Paints 21 and 22 are shown in Table 8. The "total filler content" in the table is as described above in Tables 5 and 6.

[0087] [Table 8]

[0088] [Coating Preparation Example 3] Each of the paints 21 and 22 was applied to an aluminum plate (A2017-T3) measuring 100 mm × 25 mm × 6 mm using a desktop coater to a target film thickness of 200 μm, and then heated and dried to produce coatings 21 and 22. In this way, samples 21 and 22 were produced, each having coatings 21 and 22 on the upper surface of the aluminum plate, as shown in Figure 4. In addition, sample 23, consisting of only an aluminum plate, was prepared as a blank.

[0089] [Heat dissipation test] The configuration of the heat dissipation test equipment will be described with reference to Figures 5 and 6. As shown in Figure 5, heat dissipation test equipment 30 includes a heating unit, a heating device 50, and a temperature recording device. As shown in Figure 6, the heating unit includes an insulating plate 41 and a planar heater 42 disposed on its surface. The insulating plate 41 is a 150mm square glass ceramic protective plate (AS ONE, 6-482-01). The heater 42 is a film sheet heater, model FSHH-P2-100-1.1A, manufactured by Tokyo Giken Kogyo Co., Ltd.

[0090] The heating device 50 is a DC power supply (Kikusui Electronics Co., Ltd., DC stabilized power supply PWR400L) and is electrically connected to the heater 42. The temperature recording device is composed of a temperature logger 61 and a K-type thermocouple 62 connected to it. The temperature logger 61 is a GL220 manufactured by GRAPHTEC Corporation.

[0091] The heating section is constructed by adhering the surface of an aluminum plate of sample S to the surface of a heater 42 on a heat insulating plate 41 with thermally conductive grease. The thermally conductive grease is thermally conductive grease G777-200 manufactured by Shin-Etsu Chemical Co., Ltd. A K-type thermocouple 62 is adhered to each surface of sample S in the heating section. A lead wire 51 from a heating device 50 is connected to the heater 42.

[0092] A heat dissipation test was conducted to measure the surface temperature of each of samples 21 to 23 when heated for 60 minutes by heater 42. The results of the heat dissipation test are shown in Table 9. In the table, "maximum surface temperature" refers to the maximum surface temperature of that sample during the test. "Maximum difference from sample 23" refers to the maximum temperature difference between the surface temperature of blank sample 23 and the surface temperatures of samples 21 and 22 during the test. "Maximum difference from sample 21" refers to the maximum temperature difference between the surface temperature of sample 21, which consists only of base paint, and the surface temperature of sample 22 during the test. Figure 7 also shows the change in surface temperature with respect to the heating time in the heat dissipation test.

[0093] [Table 9]

[0094] <Consideration> The surface temperatures of Samples 21 and 22, which have coatings, are lower than the surface temperature of Sample 23, which is a blank (no coating). This is because the emissivity of the resin in the coating is higher than the emissivity of aluminum. Furthermore, Sample 22, which contains a thermally emissive filler (aluminum nitride) in the coating, had a maximum surface temperature that was approximately 3°C lower and a maximum temperature difference that was 5.3°C lower than Sample 21, which does not contain this filler. This is thought to be due to the difference in thermal conductivity of the coating. From the above, it can be seen that the radiation performance of a coating increases with both emissivity and thermal conductivity. [Explanation of symbols]

[0095] 1 Gas-insulated equipment 2 containers 3. Gas circuit breaker 4 Lightning arrester 5. Potential transformers 6 Disconnector 7 Cable connection 8 Earthing switch 9 Current transformers 10 Simple disconnect device 11 Bulkhead 20 Coating 21 Matrix Phase 22 Thermally emissive filler 30 Thermal Test Equipment 41 Insulation board 42 Heater 50 Heating device 51 conductor 61 Temperature Logger 62 K thermocouple S sample

Claims

1. A conductor that constitutes an electric circuit, a container that accommodates the conductor and in which an insulating gas is pressurized, and a coating formed on a part or all of the surface of one or both of the conductor and the container, the coating is composed of a binder resin and a filler, The filler includes a thermally emissive filler having an emissivity of 0.7 or more; and A gas insulated equipment, wherein the content of the thermally emissive filler in the coating is 30% by volume or more.

2. 2. The gas insulating equipment according to claim 1, wherein the coating contains the filler in an amount of 80% by volume or less.

3. 2. The gas insulated equipment according to claim 1, wherein the particle size of the thermally emissive filler is 0.1 to 10 μm.

4. The gas insulated equipment according to claim 1 , wherein the thermally emissive filler is an inorganic filler.

5. 2. The gas insulated equipment according to claim 1, wherein the coating has a thickness of 200 [mu]m or less.

6. 2. The gas insulated equipment according to claim 1, wherein the portion of the surface covered with the coating is roughened.

7. The method includes a step of applying a coating paint to a part or the whole of a surface of one or both of a conductor constituting an electric circuit in a gas-insulated equipment and a container that accommodates the conductor and is filled with an insulating gas under pressure, A method for producing gas insulated equipment using a coating material containing 30 mass % or more of a coating component including a thermally emissive filler having an emissivity of 0.7 or more.

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