Dielectric, dielectric composition and its applications, electrical device, and supply method

Abstract

The dielectric includes a halogenated olefin having a carbon number of 2 or more and 4 or less, and the dielectric has a mass-based water content of 6000 ppm or less.

Description

Technical Field

[0001] The present disclosure relates to dielectrics, dielectric compositions and applications thereof, electrical devices, and supply methods. Background Art

[0002] In medium- and high-voltage electrical devices, gases enclosed within sealed containers are typically used for electrical insulation and, if necessary, arc extinguishing. Currently, the most commonly used gas is sulfur hexafluoride (SF6). SF6 has relatively high insulation resistance, good thermal conductivity, and low dielectric loss. It is chemically inactive and non-toxic to humans and animals, and recombines almost completely after arc separation. Furthermore, it is non-flammable and remains inexpensive.

[0003] However, SF6 has a global warming potential (GWP) of 23,500 over 100 years, using CO2 as a benchmark, and a residual period in the atmosphere of 3,200 years. Therefore, it is known as one of the gases with a strong global warming effect.

[0004] As an alternative to sulfur hexafluoride, it is known to use naturally occurring gases such as air and nitrogen, which have a lower environmental impact than sulfur hexafluoride. However, these gases have lower dielectric strength than sulfur hexafluoride. Therefore, using these gases for electrical insulation or arc extinguishing in medium- and high-voltage electrical equipment requires a significant increase in the size of the equipment or the gas filling pressure. Therefore, the use of naturally occurring gases as an alternative to sulfur hexafluoride, in pursuit of increasingly compact electrical equipment, contradicts decades of effort.

[0005] From the perspectives of electrical characteristics and GWP, iodocarbons such as trifluoroiodomethane are promising alternatives. However, the binding energy between the iodine atom and the carbon atom in iodocarbons is extremely low compared to that of other halogen atoms. Therefore, the bond between the iodine atom and the carbon atom is easily broken, leading to decomposition.

[0006] Mixtures of sulfur hexafluoride with other gases, such as nitrogen or nitrogen dioxide, are used to limit its environmental impact. However, sulfur hexafluoride has a high GWP, so the GWP of these mixtures remains very high. For example, a mixture of sulfur hexafluoride and nitrogen in a 10 / 90 volume ratio has a dielectric strength of only 59% of that of sulfur hexafluoride at an AC voltage (50 Hz), but its GWP is approximately 8000 to 8650. Therefore, using such mixtures as gases to reduce environmental impact is considered undesirable.

[0007] As another example of a substitute for sulfur hexafluoride, various dielectric gaseous compounds are known (for example, see Patent Document 1).

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application No. 2010-512639 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] Among the various dielectric gaseous compounds described in Patent Document 1, halogenated olefins are listed as one of the compounds that are expected to be substitutes for sulfur hexafluoride because of their low GWP and low toxicity to humans and animals.

[0013] However, the incorporation of moisture reduces the stability of halogenated olefins, and they may decompose over time. Furthermore, decomposition of halogenated olefins produces decomposition products containing halogen atoms such as fluorine and chlorine, which can corrode metal materials in electrical devices. Furthermore, moisture can also affect the insulation, interruption, and electrical performance of insulating devices. Therefore, moisture management, as a key element of product quality management, is crucial, as is moisture management during the filling process of electrical equipment and within the equipment itself.

[0014] The present disclosure has been made in view of the above-mentioned conventional situation, and an object of the present disclosure is to provide a dielectric and a dielectric composition having excellent stability, as well as applications of the dielectric composition, an electric device using the dielectric composition, and a method for supplying the dielectric composition.

[0015] Solutions for solving problems

[0016] The specific solutions for achieving the aforementioned objectives are as follows.

[0017] <1> A dielectric material comprising a halogenated olefin having a carbon number of 2 or more and 4 or less, wherein the dielectric material has a water content of 6000 ppm or less based on mass.

[0018] <2> according to <1> The dielectric described above, wherein the halogenated olefin includes at least one selected from the group consisting of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, (E)-1,1,1,4,4,4-hexafluorobut-2-ene, (Z)-1,1,1,4,4,4-hexafluorobut-2-ene, (E)-1-chloro-3,3,3-trifluoropropene, (Z)-1-chloro-3,3,3-trifluoropropene, 1,1-difluoroethylene, (Z)-1,2-difluoroethylene, (E)-1,2-difluoroethylene, trifluoroethylene, 2,3,3,3-tetrafluoro-1-propene, (E)-1,3,3,3-tetrafluoropropene, and (Z)-1,3,3,3-tetrafluoropropene.

[0019] <3> according to <1> or <2> The dielectric, wherein the halogenated olefin contains at least one of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene.

[0020] <4> A dielectric composition comprising: a halogenated olefin having a carbon number of 2 or more and 4 or less; and a diluent gas, wherein the diluent gas includes carbon dioxide, and wherein the dielectric composition has a water content of 6000 ppm or less based on mass.

[0021] <5> A dielectric composition comprising: a halogenated olefin having a carbon number of 2 or more and 4 or less; and a diluent gas, wherein the diluent gas comprises air, and wherein the dielectric composition has a water content of 800 ppm or less based on mass.

[0022] <6> according to <4> or <5> The dielectric composition contains the halogenated olefin at a content of 70% by volume or less in a gaseous state.

[0023] <7> according to <4> ~ <6> The dielectric composition according to any one of the preceding claims, wherein the halogenated olefin comprises at least one of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene.

[0024] The total amount of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene in the dielectric composition in a gas phase is 70% by volume or less.

[0025] <8> according to <4> ~ <7> The dielectric composition according to any one of the preceding claims has a condensation temperature of 0° C. or lower.

[0026] <9> according to <4> ~ <8> The dielectric composition according to any one of the preceding claims, wherein the water content of the dilution gas is 2.0 ppm to 6000.0 ppm on a mass basis.

[0027] <10> according to <4> ~ <9> The dielectric composition described in any one of the preceding claims is used as at least one of an electrical insulating medium and an arc extinguishing medium.

[0028] <11> An electrical device comprising: a motor component; and a <4> ~ <10> A sealed container for the dielectric composition described above.

[0029] <12> according to <11> The electrical device is a circuit breaker, a current breaking device, a gas-insulated transmission line, a gas-insulated transformer, a gas-insulated substation, a gas-insulated switchgear, a gas-insulated circuit breaker or a gas-insulated load switchgear.

[0030] <13> A supply method, the supply method <4> ~ <10> The dielectric composition described in any one of the above is supplied to <11> or <12> electrical devices.

[0031] <14> <4> ~ <10> Use of the dielectric composition described above as at least one of an electrical insulating medium and an arc extinguishing medium.

[0032] Effects of the Invention

[0033] According to the present disclosure, a dielectric and a dielectric composition having excellent stability, applications of the dielectric composition, an electric device using the dielectric composition, and a method for supplying the dielectric composition can be provided. DETAILED DESCRIPTION

[0034] Hereinafter, the methods for implementing the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps, etc.) are not essential unless otherwise specified. The same also applies to numerical values and their ranges, which do not limit the present disclosure.

[0035] In this disclosure, "medium voltage" refers to a voltage of 1000 volts or more in AC and 1500 volts or more in DC, but not exceeding 52000 volts in AC and 75000 volts in DC.

[0036] In this disclosure, “high voltage” refers to a voltage of 52,000 volts or higher in AC and a voltage of 75,000 volts or higher in DC.

[0037] In the present disclosure, in a numerical range expressed using “to”, the numerical values described before and after “to” are included as the minimum value and the maximum value, respectively.

[0038] <Dielectric>

[0039] The dielectric of the present disclosure contains a halogenated olefin having a carbon number of 2 or more and 4 or less, and has a mass-based water content of 6000 ppm or less. Hereinafter, a halogenated olefin having a carbon number of 2 or more and 4 or less may be referred to as a specific olefin.

[0040] The dielectric of the present disclosure has a mass-based water content of 6000 ppm or less, which tends to suppress the decomposition of specific olefins derived from water. Therefore, it is estimated that the dielectric of the present disclosure has excellent stability.

[0041] In this disclosure, the moisture content of the dielectric and diluent gas refers to the value measured by the Karl Fischer method for liquid dielectrics and diluent gases at 25°C. It refers to the value measured by the dew point method for gaseous dielectrics and diluent gases at 25°C.

[0042] From the perspective of stability, the water content of the dielectric by mass is preferably 1000 ppm or less, more preferably 800 ppm or less, further preferably 750 ppm or less, and particularly preferably 600 ppm or less. It should be noted that the water content of the dielectric by mass may be 500 ppm or less, 420 ppm or less, 370 ppm or less, 300 ppm or less, 150 ppm or less, 120 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 20 ppm or less.

[0043] Furthermore, from the viewpoint of production cost, the water content of the dielectric material based on mass is preferably 0.1 ppm or more, and more preferably 1.0 ppm or more.

[0044] The specific olefin is not particularly limited as long as it has 2 to 4 carbon atoms and contains a carbon-carbon double bond and at least one halogen atom in the molecule.

[0045] From the viewpoint of low environmental impact and excellent insulation and arc-extinguishing properties, the specific olefin preferably contains a fluorine atom.

[0046] From the viewpoint of improving the insulating properties of the specific olefin, it is preferred that more halogen atoms are present in the molecule, and chlorine atoms are more preferred than fluorine atoms.

[0047] However, when the specific olefin contains fluorine atoms and chlorine atoms, the number of chlorine atoms is preferably 2 or less, more preferably 1, from the viewpoint of making the boiling point of the specific olefin within a range suitable for dielectric applications.

[0048] The specific olefins may be used alone or in combination of two or more.

[0049] The GWP of a particular olefin may be 500 or less, 200 or less, 150 or less, 100 or less, 50 or less, 20 or less, 15 or less, 10 or less, 7 or less, 5 or less, 4 or less, or 3 or less.

[0050] GWP is defined for carbon dioxide over 100 years using the method described in "The scientific assessment of ozone depletion, 2002, a report of the World Meteorological Association's Global Ozone Research and Monitoring Project."

[0051] As specific examples of the specific olefin, at least one selected from the group consisting of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, (E)-1,1,1,4,4,4-hexafluorobut-2-ene, (Z)-1,1,1,4,4,4-hexafluorobut-2-ene, (E)-1-chloro-3,3,3-trifluoropropene, (Z)-1-chloro-3,3,3-trifluoropropene, 1,1-difluoroethylene, (Z)-1,2-difluoroethylene, (E)-1,2-difluoroethylene, trifluoroethylene, 2,3,3,3-tetrafluoro-1-propene, (E)-1,3,3,3-tetrafluoropropene and (Z)-1,3,3,3-tetrafluoropropene is preferred, and more preferably At least one selected from the group consisting of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, (E)-1,1,1,4,4,4-hexafluorobut-2-ene, (Z)-1,1,1,4,4,4-hexafluorobut-2-ene, (E)-1-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoro-1-propene, (E)-1,3,3,3-tetrafluoropropene and (Z)-1,3,3,3-tetrafluoropropene, more preferably at least one selected from (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene, and particularly preferably (Z)-1-chloro-2,3,3,3-tetrafluoropropene. Hereinafter, the mixture of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene may be referred to as 1-chloro-2,3,3,3-tetrafluoropropene.

[0052] (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene are non-flammable. Therefore, when (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, or 1-chloro-2,3,3,3-tetrafluoropropene is mixed and used with another specific olefin as the specific olefin, the combustion suppression effect of the specific olefin as a whole is excellent.

[0053] For example, when (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, or 1-chloro-2,3,3,3-tetrafluoropropene and 2,3,3,3-tetrafluoro-1-propene are used in combination as the specific olefin, in order to improve the combustion suppression effect, the content of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, or 1-chloro-2,3,3,3-tetrafluoropropene in the total amount of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, or 1-chloro-2,3,3,3-tetrafluoropropene and 2,3,3,3-tetrafluoro-1-propene may be 24.8% by volume or more.

[0054] Furthermore, when (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, or 1-chloro-2,3,3,3-tetrafluoropropene and (E)-1,3,3,3-tetrafluoropropene are used in combination as the specific olefin, in order to improve the combustion suppression effect, the content of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, or 1-chloro-2,3,3,3-tetrafluoropropene in the total amount of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, 1-chloro-2,3,3,3-tetrafluoropropene, and (E)-1,3,3,3-tetrafluoropropene may be 16.1% by volume or more.

[0055] When the specific olefin contains (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene, the ratio of (Z)-1-chloro-2,3,3,3-tetrafluoropropene to the total of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene is preferably 50 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and particularly preferably 95 mol% or more.

[0056] The dielectric of the present disclosure may contain at least one trace component selected from the group consisting of chlorine, hydrogen fluoride, hydrogen chloride, acetic acid, carbonyl fluoride, carbonyl chloride, trifluoroacetic acid fluoride, acetyl chloride, carbon monoxide, formyl chloride, and chloroform. Hereinafter, these trace components may be referred to as first specific trace components.

[0057] The first specific trace component itself reacts with metal materials, or when dissolved in water and in contact with metal materials, there is a concern that it may cause degradation or embrittlement of the metal materials. Therefore, when the dielectric of the present disclosure contains the first specific trace component, the mass-based content of the first specific trace component is preferably 5000 ppm or less, 3000 ppm or less, 1000 ppm or less, 500 ppm or less, 250 ppm or less, 100 ppm or less, 50 ppm or less, or 20 ppm or less.

[0058] On the other hand, the content of the first specific trace component is preferably 0 ppm, but may be 5 ppm or more, or 10 ppm or more.

[0059] The dielectric of the present disclosure may contain a specific olefin; and at least one trace component selected from the group consisting of fluorocarbons, chlorofluorocarbons, fluoroolefins other than the compounds listed as specific examples of the specific olefins, chlorofluoroolefins other than the compounds listed as specific examples of the specific olefins, chloroolefins other than the compounds listed as specific examples of the specific olefins, chlorofluoroalkynes, methanol, ethanol, acetone, hexane, and ethylene. These trace components may be referred to as second specific trace components below.

[0060] When the dielectric of the present disclosure contains a specific olefin and a second specific trace component, the specific olefin is preferably at least one selected from the group consisting of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoro-1-propene and (E)-1,3,3,3-tetrafluoropropene, and more preferably at least one of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene.

[0061] In this disclosure, fluorocarbon refers to a saturated hydrocarbon compound containing fluorine atoms as halogen atoms in the molecule but not containing chlorine atoms. Fluorocarbon may or may not contain hydrogen atoms in the molecule.

[0062] In this disclosure, chlorofluorocarbon refers to a saturated hydrocarbon compound containing fluorine and chlorine atoms as halogen atoms in the molecule. Chlorofluorocarbon may or may not contain hydrogen atoms in the molecule.

[0063] In the present disclosure, a fluoroolefin refers to an ethylene-based hydrocarbon compound containing a fluorine atom as a halogen atom in the molecule but not containing a chlorine atom. The fluoroolefin may or may not contain a hydrogen atom in the molecule.

[0064] In the present disclosure, chlorofluoroolefins refer to ethylene-based hydrocarbon compounds containing fluorine and chlorine atoms as halogen atoms in the molecule. Chlorofluoroolefins may or may not contain hydrogen atoms in the molecule.

[0065] In the present disclosure, chloroolefins refer to ethylene-based hydrocarbon compounds containing chlorine atoms as halogen atoms in their molecules. Chloroolefins may or may not contain hydrogen atoms in their molecules.

[0066] In the present disclosure, chlorofluoroalkyne refers to an acetylene hydrocarbon compound containing fluorine and chlorine atoms as halogen atoms in the molecule. Chlorofluoroalkyne may or may not contain hydrogen atoms in the molecule.

[0067] The second specific trace component may contain a fluorocarbon. Examples of the fluorocarbon include at least one selected from the group consisting of 1,1,1,2-tetrafluoropropane, 1,1,1,3,3-pentafluoropropane, 1,1,1,2,2,3,3-heptafluoropropane, tetrafluoromethane, a fluorinated hydrocarbon represented by C4H6F4, trifluoromethane, and fluoroethane. Examples of the fluorinated hydrocarbon represented by C4H6F4 include 1,1,2,3-tetrafluorobutane.

[0068] The second specific trace component may contain chlorofluorocarbons. Examples of the chlorofluorocarbons include at least one selected from the group consisting of 1,3-dichloro-1,1,2,2,3-pentafluoropropane, 2-chloro-1,1,1,2-tetrafluoropropane, 3,3-dichloro-1,1,1,2,2-pentafluoropropane, and chlorotrifluoromethane.

[0069] The second specific trace component may contain a fluoroolefin other than the compounds listed as specific examples of the specific olefin. Examples of the fluoroolefin other than the compounds listed as specific examples of the specific olefin include at least one selected from the group consisting of a fluorinated hydrocarbon represented by C4H4F4 and tetrafluoroethylene. Examples of the fluorinated hydrocarbon represented by C4H4F4 include 1,3,4,4-tetrafluoro-1-butene, 3,4,4,4-tetrafluoro-1-butene, 1,1,2,3-tetrafluoro-1-butene, and 2,4,4,4-tetrafluoro-1-butene.

[0070] The second specific trace component may contain chlorofluoroolefins other than the compounds listed as specific examples of the specific olefin. Examples of chlorofluoroolefins other than the compounds listed as specific examples of the specific olefin include at least one selected from the group consisting of 1,1-dichloro-2,3,3,3-tetrafluoropropene, (Z)-2-chloro-1,3,3,3-tetrafluoropropene, (E)-2-chloro-1,3,3,3-tetrafluoropropene, 2-chloro-1,1,3,3,3-pentafluoro-1-propene, 2-chloro-3,3,3-trifluoropropene, 1,2-dichloro-1-fluoroethylene, and 1,1,2-trichloro-2-fluoroethylene.

[0071] The second specific trace component may contain chloroolefins other than the compounds listed as specific examples of the specific olefins. Examples of chloroolefins other than the compounds listed as specific examples of the specific olefins include 1,1,2,2-tetrachloroethylene.

[0072] The second specific trace component may contain chlorofluoroalkyne. Examples of the chlorofluoroalkyne include 1-chloro-3,3,3-trifluoro-1-propyne.

[0073] The second specific trace component is considered to have a function of suppressing the decomposition of the specific olefin and stabilizing it, but the reason is unclear.

[0074] When the dielectric of the present disclosure contains a specific olefin and a second specific trace component, the mass-based content of the second specific trace component is preferably 15,000 ppm or less, more preferably 10,000 ppm or less, from the viewpoint of ensuring further stability.

[0075] On the other hand, the content of the second specific trace component is preferably 0 ppm, but may be 4 ppm or more, 50 ppm or more, or 100 ppm or more.

[0076] The dielectric of the present disclosure may contain a specific olefin, a first specific trace component, and a second specific trace component. When the dielectric of the present disclosure contains the first specific trace component and the second specific trace component, the preferred ranges of their contents are as described above.

[0077] When the dielectric of the present disclosure contains at least one of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene, the second specific trace component, and the first specific trace component, the desirable range of the mass-based content of the first specific trace component is as described above.

[0078] The dielectric material of the present disclosure may be stored in a gas state or a liquid state at 25° C., or may be in a state where gas and liquid coexist.

[0079] <Dielectric composition>

[0080] The first dielectric composition of the present disclosure contains the dielectric of the present disclosure and a diluent gas.

[0081] The second dielectric composition disclosed herein contains a halogenated olefin having a carbon number of 2 or more and 4 or less, and a diluent gas, wherein the diluent gas includes carbon dioxide, and the second dielectric composition has a water content of 6000 ppm or less based on mass.

[0082] The third dielectric composition disclosed herein contains a halogenated olefin having a carbon number of 2 or more and 4 or less, and a diluent gas, wherein the diluent gas includes air, and the third dielectric composition has a water content of 800 ppm or less based on mass.

[0083] The details of the halogenated olefin having 2 or more and 4 or less carbon atoms contained in the second and third dielectric compositions are the same as those listed in the dielectric section of the present disclosure. The water content, based on mass, of the halogenated olefin having 2 or more and 4 or less carbon atoms used in the second and third dielectric compositions is not particularly limited.

[0084] Hereinafter, the first dielectric composition, the second dielectric composition, and the third dielectric composition may be collectively referred to simply as a "dielectric composition."

[0085] The second dielectric composition of the present disclosure has a water content of 6000 ppm or less based on mass, which tends to suppress the decomposition of specific olefins derived from water. Therefore, it is estimated that the second dielectric composition has excellent stability.

[0086] Furthermore, the third dielectric composition of the present disclosure has a mass-based water content of 800 ppm or less, which tends to suppress the decomposition of specific olefins derived from water. Therefore, it is estimated that the third dielectric composition has excellent stability.

[0087] The first dielectric composition of the present disclosure is obtained by mixing the dielectric of the present disclosure with a diluent gas.

[0088] The second or third dielectric composition of the present disclosure is obtained by mixing a specific olefin with a diluent gas.

[0089] The second or third dielectric composition of the present disclosure may contain at least one of the first specific trace component and the second specific trace component. When the second or third dielectric composition of the present disclosure contains at least one of the first specific trace component and the second specific trace component, the preferred ranges of their contents are as described above.

[0090] Compared to dielectric materials alone, the dielectric composition disclosed herein does not condense even at relatively low temperatures, such as approximately -20°C, and has a wide operating temperature range. As a result, insulation properties can be obtained even at low temperatures.

[0091] Furthermore, when the dielectric composition of the present disclosure is used in a gas interrupter or the like, fluorine atoms having high electron adhesion can be caused to flow at a high flow rate, and as a result, the interruption performance can be effectively improved.

[0092] The diluent gas is a compound having a boiling point lower than that of the dielectric of the present disclosure and having a lower dielectric strength than that of the dielectric of the present disclosure at a reference temperature of 20° C., for example.

[0093] As the diluent gas, it is preferred to use at least one selected from the group consisting of air, nitrogen, methane, oxygen, nitric oxide, helium, xenon and carbon dioxide, and more preferred to use at least one selected from the group consisting of air, nitrogen, oxygen and carbon dioxide.

[0094] The second dielectric composition contains carbon dioxide as a diluent gas. In the second dielectric composition, the ratio of carbon dioxide contained in the diluent gas is preferably 70 volume % or more, more preferably 90 volume % or more, further preferably 99 volume % or more, and particularly preferably 100 volume %.

[0095] In the second dielectric composition, components other than carbon dioxide contained in the diluent gas are not particularly limited, and examples thereof include oxygen and water. When oxygen is further present in the second dielectric composition, the ratio of oxygen contained in the diluent gas is preferably 30% by volume or less, and more preferably 10% by volume or less.

[0096] The third dielectric composition contains air as a diluent gas. In the third dielectric composition, the ratio of air contained in the diluent gas is preferably 70 volume % or more, more preferably 90 volume % or more, further preferably 99 volume % or more, and particularly preferably 100 volume %.

[0097] In the third dielectric composition, components other than air contained in the dilution gas are not particularly limited, and examples thereof include water.

[0098] The mass-based water content of the dilution gas is preferably 2.0 ppm to 6000.0 ppm, more preferably 2.0 ppm to 2600.0 ppm, further preferably 2.0 ppm to 1100.0 ppm, and particularly preferably 2.0 ppm to 400.0 ppm.

[0099] The water content of the dilution gas refers to the water content before the dilution gas is mixed with the dielectric.

[0100] The content of the dielectric or specific olefin in the dielectric composition when it is in a gaseous phase is not particularly limited. However, from the perspective of achieving the condensation temperature required for the dielectric composition to exist solely in a gaseous phase, it is preferably 70% by volume or less, 60% by volume or less, 50% by volume or less, 40% by volume or less, 30% by volume or less, 25% by volume or less, 20% by volume or less, 15% by volume or less, 10% by volume or less, or 5% by volume or less. From the perspective of insulation performance and arc extinguishing performance, the content of the dielectric or specific olefin in the dielectric composition when it is in a gaseous phase is preferably 1% by volume or more, 2% by volume or more, or 3% by volume or more.

[0101] When the dielectric contains at least one of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene as the specific olefin, from the viewpoint of achieving the condensation temperature required for the dielectric composition to exist only in a gaseous phase, the total amount of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene in the dielectric composition when the dielectric composition is in a gaseous phase is preferably 70% by volume or less, 60% by volume or less, 50% by volume or less, 40% by volume or less, 30% by volume or less, 25% by volume or less, 20% by volume or less, 15% by volume or less, 10% by volume or less, or 5% by volume or less. From the viewpoint of insulation performance and arc extinguishing performance, the total amount of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene in the dielectric composition when the dielectric composition is in a gas phase is preferably 1 volume % or more, 2 volume % or more, or 3 volume % or more.

[0102] From the perspective of maintaining the dielectric composition in a gaseous state, the condensation temperature of the dielectric composition is preferably 0°C or lower, more preferably -70 to 0°C, even more preferably -70 to -10°C, particularly preferably -70 to -20°C, and extremely preferably -70 to -30°C. From the perspective of economic efficiency, the condensation temperature of the dielectric composition may be -70°C or higher.

[0103] Examples of a preferred combination of the dielectric and the diluent gas in the first dielectric composition include a combination of at least one of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene and at least one selected from the group consisting of air, nitrogen, oxygen, and carbon dioxide.

[0104] From the perspective of stability, the water content of the first dielectric composition, based on mass, is preferably 6000 ppm or less, 5000 ppm or less, 4000 ppm or less, 3000 ppm or less, 2500 ppm or less, 1000 ppm or less, 800 ppm or less, 500 ppm or less, 420 ppm or less, 370 ppm or less, 300 ppm or less, 150 ppm or less, 120 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 20 ppm or less. From the perspective of economic efficiency, the water content of the dielectric composition, based on mass, is preferably 3 ppm or more, 5 ppm or more, 7 ppm or more, 10 ppm or more, or 15 ppm or more.

[0105] From the perspective of stability, the water content of the second dielectric composition by mass is preferably 6000 ppm or less, 5000 ppm or less, 4000 ppm or less, 3000 ppm or less, 2500 ppm or less, 1000 ppm or less, 800 ppm or less, 500 ppm or less, 420 ppm or less, 370 ppm or less, 300 ppm or less, 150 ppm or less, 120 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 20 ppm or less. From the perspective of economic efficiency, the water content of the second dielectric composition by mass is preferably 3 ppm or more, 5 ppm or more, 7 ppm or more, 10 ppm or more, or 15 ppm or more.

[0106] From the perspective of stability, the third dielectric composition preferably has a water content by mass of 800 ppm or less, 500 ppm or less, 420 ppm or less, 370 ppm or less, 300 ppm or less, 150 ppm or less, 120 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 20 ppm or less. From the perspective of economic efficiency, the third dielectric composition preferably has a water content by mass of 3 ppm or more, 5 ppm or more, 7 ppm or more, 10 ppm or more, or 15 ppm or more.

[0107] The water content of the dielectric composition is a value measured by a dew point method, for example, by the method described in International Electrotechnical Commission (IEC) 60376:2005.

[0108] The dielectric composition disclosed herein is used as at least one of an electrical insulating medium and an arc-extinguishing medium, and is particularly suitable for use as an electrical insulating medium and an arc-extinguishing medium in medium-voltage or high-voltage electrical devices.

[0109] The dielectric composition of the present disclosure may be in a gas state or a liquid state at 25° C., or may be a mixture of gas and liquid. The dielectric composition is preferably in a gas state before supply to an electrical device or in an electrical device.

[0110] To prevent condensation of the dielectric composition in the vapor phase, the application temperature of the dielectric composition of the present disclosure is preferably higher than the condensation temperature of the dielectric composition. From the perspective of climate and usage environment, the application temperature is preferably -30°C or higher, -25°C or higher, -20°C or higher, -15°C or higher, -10°C or higher, -5°C or higher, 0°C or higher, 5°C or higher, or 10°C or higher. Furthermore, from the perspective of the design pressure of the equipment, the application temperature is preferably 50°C or lower, 40°C or lower, 30°C or lower, 25°C or lower, or 20°C or lower.

[0111] It should be noted that the “operating temperature” refers to the temperature of the gas in the sealed container containing the dielectric composition, and this temperature may fluctuate over time depending on climatic conditions or environmental conditions.

[0112] It should be noted that the dielectric composition of the present disclosure ideally does not condense over the entire intended operating temperature range. By using a diluent gas, the saturated vapor pressure of the dielectric composition of the present disclosure can be avoided from being reached over the entire intended operating temperature range.

[0113] From the perspective of suppressing condensation of the dielectric composition in both medium and high voltage electrical devices, the application pressure of the dielectric composition of the present disclosure can be set to 0.1 MPa to 0.15 MPa, 0.15 MPa to 0.3 MPa, 0.3 MPa to 0.5 MPa, 0.5 MPa to 0.7 MPa, 0.7 MPa to 0.9 MPa, 0.9 MPa to 1 MPa, or 1 MPa to 1.5 MPa in terms of gauge pressure.

[0114] <Electrical Equipment>

[0115] The electric device of the present disclosure includes: a motor component; and a sealed container containing the dielectric composition of the present disclosure.

[0116] Specific examples of the electrical device include a circuit breaker, a current interrupter, a gas-insulated transmission line, a gas-insulated transformer, a gas-insulated substation, a gas-insulated switchgear, a gas-insulated circuit breaker, and a gas-insulated load switchgear.

[0117] For electrical devices, it is advantageous to use a heating device in combination with the dielectric composition to ensure that the dielectric properties, thermal properties, and interruption properties of the dielectric composition are sufficient within a standard or desired temperature range. The heating device can be used according to the temperature, pressure, or density of the dielectric composition.

[0118] For example, a heat dissipating resistor disposed at the lowest point of the electrical device, where condensed liquid is collected by gravity on various components within the device, may be preferably used as the heating device.

[0119] In this way, a higher air pressure than the test pressure, which is the air pressure inside the electrical device during the evaluation test specified in the standard, is ensured.

[0120] For the same reasons, it is advantageous to insulate the walls of the electrical device, to insulate the electrical device or the building housing the electrical device as needed, and to further heat the electrical device or the building as needed.

[0121] <Supply Method>

[0122] The supply method disclosed herein supplies the dielectric composition disclosed herein to the electrical device disclosed herein. In the supply method disclosed herein, the dielectric composition can be supplied into a sealed container included in the electrical device. The dielectric composition disclosed herein can be in a state where one or both of a liquid and a gas exist, or in a critical state.

[0123] When the dielectric composition is supplied into a sealed container, the container may be filled as the dielectric composition, or the dielectric or the specific olefin and the diluent gas may be filled separately.

[0124] Example

[0125] Hereinafter, the present disclosure will be described in detail with reference to experimental examples, but the present disclosure is not limited to the following experimental examples.

[0126] (Dielectric Evaluation (1))

[0127] As the dielectric, 1-chloro-2,3,3,3-tetrafluoropropene with a purity of 99.75% and a molar ratio of the Z-isomer to the E-isomer, i.e., a Z / E ratio of 99.4 / 0.6, was used; 2,3,3,3-tetrafluoro-1-propene with a purity of 99.91% was used; and (E)-1,3,3,3-tetrafluoropropene with a purity of 99.97% was used.

[0128] In a SUS316 pressure-resistant container with an internal volume of 200cc (mL), a maximum operating temperature of 300°C, and a maximum operating pressure of 20MPa in gauge pressure, an inner tube made of Pyrex (registered trademark) whose weight was measured in advance was inserted. The amount (mass basis) of water recorded in Table 1 was pre-added to the inner tube. As metal sheets, one cold-rolled steel sheet as an iron sheet and one SPCC, copper sheet, and aluminum sheet as a steel strip were prepared and hung together from the upper part of the inner tube. The size of each metal sheet was 25mm×30mm×2mm. After the pressure-resistant container was sealed, the container was cooled, the moisture was solidified, and the container was vacuum-exhausted. Next, 50g of dielectric was filled in the above-mentioned pressure-resistant container, the container was placed in a thermostatic bath, and kept at 150°C for 120 hours. After 120 hours, the pressure-resistant container was taken out from the thermostatic bath and evaluated as follows.

[0129] (Determination of acid content)

[0130] The pressure-resistant container after the above test is left to stand until it reaches room temperature (25°C, the same applies below). In the pressure-resistant container at room temperature, 100 ml of pure water is collected in each of the four absorption bottles. Each absorption bottle is connected in series with a catheter, and the valve of the pressure-resistant container is slowly opened. The dielectric is introduced into the water in the absorption bottle to extract the acid component. The water collected in the first and second absorption bottles from the upstream side of the absorption bottle after extraction is mixed, and 1 drop of BTB (bromothymol blue) as an indicator is added, and titrated using a 1 / 100N-NaOH base standard solution. The water collected in the third and fourth absorption bottles from the upstream side of the absorption bottle is mixed and titrated in the same manner as a measurement blank. From these measured values and the value of the measurement blank, the mass-based concentration of the acid component is calculated as the HCl concentration.

[0131] The metal pieces were then removed from the container and their appearance was visually observed. Changes in appearance were evaluated based on the following criteria. The evaluation results are shown in Table 1. Examples 1-1 to 1-9, 1-11 to 1-13, and 1-15 to 1-17 in Table 1 are examples, and Examples 1-10, 1-14, and 1-18 are comparative examples.

[0132] (Evaluation criteria for acid content)

[0133] A: less than 0.5ppm (lower detection limit)

[0134] B: 0.5ppm or more and less than 1.0ppm

[0135] C: 1.0ppm or more and less than 10.0ppm

[0136] D: 10.0 ppm or more (evaluation standard based on visual observation)

[0137] A: No change on the surface of all metals

[0138] B: Slight discoloration on some metal surfaces

[0139] C: The metal surface is significantly discolored in some metals. D: The metal surface is significantly discolored in all metals. [Table 1]

[0140]

[0141] As shown in Table 1, no effect of moisture was observed on the acid components or the appearance of the metal sheet until the water concentration reached 500 ppm. The effect of moisture gradually emerged at water concentrations between 750 ppm and 5000 ppm. A significant effect was observed at 10000 ppm. This is believed to be due to the coexistence of the dielectric with moisture, which hydrolyzes the dielectric and generates acid components, which corrode the metal sheet.

[0142] In addition, even when other specific olefins other than the dielectrics shown in Table 1 were used, the same results as those of the above-mentioned experimental examples were obtained.

[0143] (Dielectric Evaluation (2) and Dielectric Composition Evaluation)

[0144] As the dielectric, those used in Examples 1-1 to 1-18 were used.

[0145] As the diluent gas, air or carbon dioxide is used.

[0146] In a pressure-resistant container made of SUS316 with an internal volume of 200cc (mL), a maximum operating temperature of 300°C, and a maximum operating pressure of 20MPa in gauge pressure, an inner tube made of Pyrex (registered trademark) of which the weight was previously measured was inserted. The amount of water (mass basis) previously described in Tables 2 to 9 was added to the inner tube. As metal sheets, one cold-rolled steel sheet as an iron sheet and one SPCC, copper sheet, and aluminum sheet as a steel strip were prepared and hung together from the upper part of the inner tube. The size of each metal sheet is 25mm×30mm×2mm. After the pressure-resistant container is sealed, the container is cooled to solidify the water and the container is vacuum-exhausted. Then, the above-mentioned pressure-resistant container is placed in a thermostatic bath and maintained at 25°C for 3 hours. After 3 hours, the pressure in the pressure-resistant container is set to a total pressure of 0.45MPa in gauge pressure, and the above-mentioned two dielectrics or the above-mentioned dielectric and dilution gas are filled at partial pressure in a manner to form the composition described in Tables 2 to 9. Thereafter, the temperature in the thermostatic bath was maintained at 150° C. for 120 hours. After 120 hours, the pressure vessel was taken out of the thermostatic bath and evaluated as follows.

[0147] (Observation of the appearance of the metal sheet)

[0148] After the test, the pressure vessel was allowed to stand until it reached room temperature. The metal piece was removed from the pressure vessel at room temperature and its appearance was visually observed. Changes in appearance were evaluated based on the aforementioned (Visual Observation Evaluation Criteria). The evaluation results are shown in Tables 2 to 9.

[0149] Examples 2-1, 2-3, 2-5, and 2-7 in Table 2 are examples, and Examples 2-2, 2-4, 2-6, and 2-8 are comparative examples.

[0150] Examples 3-1 to 3-12 in Table 3 are examples, and Example 3-13 is a comparative example.

[0151] Examples 4-1 to 4-3, 4-5 to 4-7, and 4-9 to 4-11 in Table 4 are examples, and Examples 4-4, 4-8, and 4-12 are comparative examples.

[0152] Examples 5-1 to 5-12 in Table 5 are examples, and Example 5-13 is a comparative example.

[0153] Examples 6-1 to 6-3, 6-5 to 6-7, and 6-9 to 6-11 in Table 6 are examples, and Examples 6-4, 6-8, and 6-12 are comparative examples.

[0154] Examples 7-1 to 7-12 in Table 7 are examples, and Example 7-13 is a comparative example.

[0155] Examples 8-1 to 8-3, 8-5 to 8-7, and 8-9 to 8-11 in Table 8 are examples, and Examples 8-4, 8-8, and 8-12 are comparative examples.

[0156] Examples 9-1, 9-3, 9-5, and 9-7 in Table 9 are examples, and Examples 9-2, 9-4, 9-6, and 9-8 are comparative examples.

[0157] [Table 2]

[0158]

[0159] [Table 3]

[0160]

[0161] [Table 4]

[0162]

[0163] [Table 5]

[0164]

[0165] [Table 6]

[0166]

[0167] [Table 7]

[0168]

[0169] [Table 8]

[0170]

[0171] [Table 9]

[0172]

[0173] As shown in Table 2, the influence of water was significantly observed up to a water concentration of 10,000 ppm.

[0174] This is considered to be because, in the comparative examples of Examples 2-1 to 2-8, the dielectric material coexists with water, causing the dielectric material to be hydrolyzed and generate acid components. When the water concentration is 10,000 ppm, the metal sheet is excessively corroded.

[0175] As shown in Tables 3 to 9, when the diluent gas in the dielectric composition is carbon dioxide, when the carbon dioxide content is 75% by volume or less, the effect of moisture is evident at a water concentration of 5000 ppm, and a significant effect is observed at 10000 ppm. For Examples 3-1 to 3-13, 5-1 to 5-13, and 7-1 to 7-13, which are examples, this is believed to be due to the effect of suppressing hydrolysis of the dielectric by adding carbon dioxide.

[0176] As shown in Tables 3 to 9, when the diluent gas for the dielectric composition is air, the effect of moisture gradually manifests itself at a water concentration of 500 to 750 ppm, regardless of the air content. A significant effect of moisture is observed at 1000 ppm. For Examples 4-1 to 4-12, Examples 6-1 to 6-12, and Examples 8-1 to 8-12, this is believed to be due to the effect of promoting hydrolysis of the dielectric by mixing air.

[0177] In addition, using combinations of specific olefins other than the dielectric combinations shown in Tables 2 to 9, similar results to those in the above experimental examples were obtained. Furthermore, using combinations of specific olefins other than the dielectrics shown in Tables 2 to 9 and diluent gases, similar results to those in the above experimental examples were obtained.

[0178] The disclosure of Japanese Patent Application No. 2020-071155 filed on April 10, 2020 is incorporated herein by reference in its entirety.

[0179] Furthermore, all documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A dielectric composition comprising: a halogenated olefin having a carbon number of 2 or more and 4 or less; and a diluent gas, wherein the diluent gas comprises carbon dioxide; the halogenated olefin content in the dielectric composition in a gaseous phase is 25% by volume or less; and the dielectric composition has a water content (based on mass) of 1000 ppm or less. The halogenated olefin contains at least one selected from the group consisting of (E)-1-chloro-2,3,3,3-tetrafluoropropene, (Z)-1-chloro-2,3,3,3-tetrafluoropropene, (E)-1-chloro-3,3,3-trifluoropropene, (Z)-1-chloro-3,3,3-trifluoropropene, 1,1-difluoroethylene, (Z)-1,2-difluoroethylene, (E)-1,2-difluoroethylene, trifluoroethylene, 2,3,3,3-tetrafluoro-1-propene, (E)-1,3,3,3-tetrafluoropropene, and (Z)-1,3,3,3-tetrafluoropropene.

2. The dielectric composition according to claim 1, wherein The halogenated olefin contains at least one of (E)-1-chloro-2,3,3,3-tetrafluoropropene and (Z)-1-chloro-2,3,3,3-tetrafluoropropene. The dielectric composition according to claim 1 , wherein the condensation temperature is 0° C. or lower.

4. The dielectric composition according to claim 1, wherein The mass-based moisture content of the dilution gas is 2.0 ppm to 6000.0 ppm. The dielectric composition according to claim 1 , which is used as at least one of an electrical insulating medium and an electrical arc extinguishing medium. 6 . An electric device comprising: a motor component; and a sealed container containing the dielectric composition according to claim 1 . 7 . The electrical device according to claim 6 , which is a circuit breaker, a gas-insulated transmission line, a gas-insulated transformer or a gas-insulated substation. The electrical device according to claim 6 , which is a current interrupting device.

9. The electric device according to claim 6, which is a gas insulated switchgear.

10. The electrical device according to claim 6, which is a gas-insulated load switchgear. 11 . A supply method for supplying the dielectric composition according to claim 1 to the electric device according to claim 6 .

12. Use of the dielectric composition according to any one of claims 1 to 5 as at least one of an electrical insulating medium and an arc extinguishing medium.

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