Insulating gas for electrical insulation or arc extinguishing instead of SF6 gas, and electrical device using same

Abstract

The present invention relates to an insulating gas for electrical insulation or arc extinguishing of an electrical device and an electrical device for electrical insulation using the insulating gas. The insulating gas capable of replacing the SF6 gas in the invention is a mixed gas of trifluoromethyl trifluorovinyl ether (CF3OCFCF2) and a carrier gas. The insulating gas according to the present invention has the characteristics of low boiling point, high insulating strength, low toxicity, and low global warming index (GWP1 or less), thereby being able to replace SF6, and reducing the global warming index while maintaining high insulating ability and arc extinguishing ability, thereby reducing greenhouse gases.

Description

Technical Field

[0001] The present invention relates to an insulating gas used for electrical insulation or arc extinguishing of an electrical device and an electrical device using the insulating gas. Background Art

[0002] SF6 gas is a gas artificially synthesized by Mosissan and Lebean in the 1900s. The SF6 molecule is an octahedron with S atoms at the center and 6 F atoms. It has stable chemical properties and has an insulation resistance equivalent to 2.5 times that of air and an arc extinguishing performance 100 times. It is an excellent material that replaces air and insulating oil used in the power industry in the past and is widely used in power equipment such as circuit breakers, high-voltage transformers, high-voltage transmission lines, and gas-insulated switchgear.

[0003] However, SF6 gas was designated as one of the six greenhouse gases by the Kyoto Protocol in 1997, and its use is restricted worldwide until 2020 because of its global warming index 23,500 times that of CO2 and its atmospheric lifetime of 3,200 years. For this reason, the power industry is conducting extensive research to develop a safe, excellent insulating, and environmentally friendly gas.

[0004] The necessary conditions that the insulating medium should have include low boiling point (below -25°C), high insulation tolerance (compared to SF6, more than 80%), low toxicity (high toxicity concentration (more than 5000ppmv) and negative gene deformation), and low global warming index (below GWP500). In the past, the insulating medium had the limitation that it could not meet all the above four necessary conditions.

[0005] For example, WO2008 / 073790 proposes various compounds with low boiling points in the range of -20°C to -273°C and GWPs below 22,200 as insulating materials. However, the global warming index range is too large to judge the environmental friendliness of individual compounds, and no experimental data is given for insulation endurance or toxicity. In addition, a dielectric gas mixture of a gas selected from nitrogen, CO2 and N2O is proposed, but the special characteristics of the mixed gas are never proposed.

[0006] EP1933432A proposes to use a mixture of trifluoroiodomethane (CF3I) and carbon dioxide as an insulating material. It has a high insulation resistance equivalent to 1.2 times that of SF6, a low boiling point of -22°C, and a low global warming factor (GWP5), but it has been found to be a genotoxic substance, so it has the disadvantage of posing a huge threat to the safety of relevant experts who have to be exposed to the gas for a long time.

[0007] WO2012 / 080246 proposes to convert fluoroketone (C5F10 Fluorone has a global warming index of less than 1, high insulation resistance equivalent to twice that of SF6, and low acute inhalation toxicity (LC 50 4h, about 20,000ppmv), but has a high boiling point of 26.5°C, so it has a disadvantage that it cannot be used not only in power equipment in polar regions but also in countries with four seasons like South Korea.

[0008] WO2013 / 151741 proposes a mixture of insulating gas containing heptafluoroisobutyronitrile ((CF3)2CFCN) and an inert gas as an insulating material. Heptafluoroisobutyronitrile has low acute inhalation toxicity (LC 50 4h, 10,000 to 15,000ppmv) and high insulation resistance equivalent to twice that of SF6, but the global warming index and boiling point are relatively high, at 2,100 and -4.7℃ respectively, and recently showed positive results for genotoxicity. The gas is mixed with CO2 to g 3 The brand name is being sold under 3M Company.

[0009] As described above, there is a problem that, despite extensive research, no substitute material that can satisfy all the necessary conditions for insulating materials has been found for materials that can replace SF6 insulating gas. Summary of the invention

[0010] Problem to be solved

[0011] In order to solve the problems of the above-mentioned background technology, the purpose of the present invention is to provide an insulating gas that meets four necessary conditions in order to replace SF6 gas, namely, low boiling point (below -25°C), high insulation resistance (more than 80% compared to SF6), low toxicity (high toxicity concentration (more than 5000ppmv) and negative gene mutation), and low global warming index (below GWP 500).

[0012] In addition, an object of the present invention is to provide an electrical device that utilizes the above-mentioned insulating gas for environmentally friendly electrical insulation or arc extinguishing.

[0013] Means of solving the problem

[0014] The insulating gas of the present invention for solving the above-mentioned problems is used for electrical insulation or arc extinguishing of electrical devices and is a mixed gas of trifluoromethyl trifluorovinyl ether (CF3OCFCF2) and a carrier gas.

[0015] In addition, the mixed gas is,

[0016] GWP is below 1,

[0017] Acute inhalation toxicity (LC 504h) above 10,000ppmv,

[0018] The mixing ratio k is such that the dielectric strength synergy effect C defined by the following mathematical formula 1 is greater than -0.1, greater than 0.08, or greater than 0.05:

[0019] (Mathematical formula 1)

[0020]

[0021] In the above mathematical formula 1, k is the mixing ratio (mol %) of the trifluoromethyl trifluorovinyl ether, Vm is the insulation breakdown voltage of the mixed gas, Va is the insulation breakdown voltage of trifluoromethyl trifluorovinyl ether, and Vb is the insulation breakdown voltage of the carrier gas.

[0022] In addition, the carrier gas is CO2,

[0023] In the mixed gas, the mixing ratio of CF3OCFCF2 can be 1 to 60 mol %.

[0024] Then, the carrier gas is CO2,

[0025] In the mixed gas, the mixing ratio of CF3OCFCF2 may be 3 to 60 mol % or 5 to 60 mol %.

[0026] In addition, the carrier gas is CO2 and O2,

[0027] The mole % of CF3OCFCF2 is x, the mole % of CO2 is y, and the mole % of O2 is z. When presented on a triangular graph, x, y, and z are outside the area surrounded by straight lines AB, BC, and CA.

[0028] The straight line AB is a straight line connecting point A and point B, the straight line BC is a straight line connecting point B and point C, and the straight line CA is a straight line connecting point C and point A;

[0029] The x, y, and z of point A can be 50, 0, and 50, the x, y, and z of point B can be 5.1, 0, and 94.9, and the x, y, and z of point C can be 8.2, 80, and 11.8.

[0030] In addition, the carrier gas is CO2 and O2,

[0031] The mixed gas comprises CF3OCFCF2 at a mixing ratio of 1 to 60 mol %, O2 at a mixing ratio of 1 to 30 mol %, and the remainder may be CO2.

[0032] Then, the carrier gas is CO2 and O2,

[0033] The mixed gas is a mixture of CF3OCFCF2 in a mixing ratio of 3 to 20 mol%, 4 to 16 mol% or 5 to 10 mol%, an O2 mixture ratio of 1 to 30 mol%, 1 to 25 mol% or 1 to 20 mol%, and the remainder may be composed of CO2.

[0034] Then, the carrier gas is CO2 and O2,

[0035] The molar ratio of CO2 to O2 can be 70:30 to 99:1, 80:20 to 95:5, or 85:15 to 90:10.

[0036] On the other hand, an electrical device for solving another problem of the present invention performs electrical insulation or arc extinguishing by an insulating gas, and uses any one of the above-mentioned insulating gases.

[0037] In addition, the electrical device may include: an insulating space filled with the insulating gas inside a casing; and a conductive component disposed inside the casing.

[0038] Then, the temperature outside the shell is -35 to 55°C, -30 to 50°C or -25 to 40°C, the pressure of the insulating space is below 1.5MpaG, 1.2MPaG or 0.9MpaG, and the voltage provided to the conductive component can be 1 to 1100kV, 1 to 1000kV or 1 to 800kV.

[0039] Effects of the Invention

[0040] The insulating gas used for electrical insulation or arc extinguishing instead of SF6 gas of the present invention is composed of a mixed gas of trifluoromethyl trifluorovinyl ether (C3OCFCF2) and a carrier gas, and has the characteristics of low boiling point, high insulation resistance, low toxicity and low global warming index (below GWP 1), so it can replace SF6.

[0041] Furthermore, the electrical device using the insulating gas of the present invention has the same or better electrical insulation and arc extinguishing capabilities than the electrical device using SF6. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The molecular structure of CF3OCFCF2 contained in the insulating gas of the present invention is shown.

[0043] Figure 2 It shows SF6, g 3 , Paschen curves of mixed gases of CO2 and O2 and CF3OCFCF2.

[0044] Figure 3 This is a graph showing the global warming index of the mixed gas according to the mixing ratio of CF3OCFCF2.

[0045] Figure 4 The mixed gas of CF3OCFCF2 and CO2 and SF6, g 3 A graph of the Paschen curve for the 50% discharge voltage.

[0046] Figure 5 It is a graph showing the synergistic effect of insulation resistance according to the mixing ratio of CF3OCFCF2.

[0047] Figure 6 It is a graph showing the 50% discharge voltage detection results of a mixed gas of CF3OCFCF2 and CO2 and SF6 with a changed mixing ratio.

[0048] Figure 7 It is a triangular diagram with CF3OCFCF2, CO2 and O2 as the three components. DETAILED DESCRIPTION

[0049] Hereinafter, embodiments of the present invention will be described in detail.

[0050] In order to replace SF6 gas, it is necessary to meet the following conditions: low boiling point (below -25°C), high insulation resistance (more than 80% compared to SF6), low toxicity (high toxicity concentration (more than 5000ppmv) and negative gene mutation), low global warming index (below GWP 500), chemical stability and appropriate cost.

[0051] As a candidate gas satisfying the above conditions, trifluoromethyl trifluorovinyl ether (CF3OCFCF2, CAS: 1187-93-5) was selected after a large number of experiments.

[0052] In the specification of the present invention, C3F6O may refer to CF3OCFCF2.

[0053] According to an embodiment of the present invention, the insulating gas replacing SF6 gas includes Figure 1 The molecular structure of CF3OCFCF2.

[0054] As shown in Table 1 below, the boiling points, vapor pressures and global warming indexes of CF3OCCFCF2, SF6 and (CF3)2CFCN are compared.

[0055] (Table 1)

[0056] Comparison of properties of SF6, (CF3)2CFCN and CF3OCFCF2

[0057] gas Boiling point(℃) Vapor pressure [psia@] (20℃) GWP <![CDATA[Acute inhalation toxicity (LC 50 4h, ppmv)]]> <![CDATA[SF6]]> -63.7 334 23,500 100,000～ <![CDATA[(CF3)2CFCN]]> -4.7 36.7 2,400 10,000～15,000 <![CDATA[CF3OCFCF2]]> -29 70.3 0.170 10,000～15,000

[0058] For CF3OCFCF2, it can be confirmed that: compared with SF6 and g3 (CF3)2CFCN, the main component of the gas, has a very low GWP, a lower boiling point and the same level of acute inhalation toxicity (LC 50 4h, 10,000~15,000ppmv). In order to test the insulation performance of CF3OCFCF2, the lightning impulse voltage in IEC 60060-1 was applied, and the 50% discharge voltage was tested 30 times. After each test, the gas collection and electrode cleaning were carried out. Here, the 50% discharge voltage refers to the voltage at which half of the flat electrode flashes and the remaining half does not flash when the standard waveform shock wave and voltage are repeatedly applied to the flat electrode using a ball.

[0059] Figure 2 It is shown that for SF6, g 3 Paschen curves of the mixed gas of ((CF3)2CFCN), CO2 (70.5 mol%) and O2 (29.5 mol%) and CF3OCCF2 for each gas at 50% discharge voltage. Here, the Paschen curve shows the 50% discharge voltage based on the pressure and the distance between the electrodes (ball to plate electrode) to confirm the insulation performance.

[0060] Based on this, it can be confirmed that CF3OCFCF2 has the same 3 In addition, it can be confirmed that it has better insulation performance than the mixed gas of CO2 (70.5 mol%) and O2 (29.5 mol%).

[0061] On the other hand, according to another embodiment of the present invention, the insulating gas replacing SF6 gas may be a mixture of CF30, CF2 and CO2 and / or O2 as carrier gas.

[0062] The mixed gas of the present invention may have a GWP of less than 1, less than 0.9, or less than 0.85. In addition, the mixed gas of the present invention may have a GWP of 0.29 to 1, 0.29 to 0.9, or 0.29 to 0.85. The following Table 2 shows the GWP and acute inhalation toxicity (LC) according to the mixing ratio (mol%) of CF3OCCF2 and CO2. 50 , ppmv). Here, the GWP calculation method follows Regulation (EU) NO517 / 2014, which indicates the median lethal concentration (LC) at 4 hours after inhalation. 50 Complies with KS B ISO10298:2012.

[0063] (Table 2)

[0064] GWP and acute inhalation toxicity according to the mixing ratio of CF3OCFCF2 and CO2 (mol%)

[0065]

[0066]

[0067] According to Table 2 above, for the mixed gas of CF3OCFCF2 and CO2, it can be confirmed that when the mixing ratio of CF3OCFCF2 is 90 to 10 mol%, the GWP is 0.190 to 0.750, which is less than about 0.003% of the GWP (23,500) of SF6. Figure 3 This is a graph showing the global warming index of the mixed gas according to the mixing ratio of CF3OCFCF2. On the other hand, Korea Electric Power Corporation stipulates that the GWP standard is below 500 for the fluorine-based mixed gas that is a common purchase specification for environmentally friendly gas-insulated switchgear above 72.5kV. In order to meet this specification, the GWP value must be reduced, and the mixed gas of CF3OCFCF2 and CO2 can be significantly lower than the above standard.

[0068] In addition, the mixed gas of the present invention has an acute inhalation toxicity (LC 50 4h) may be 10,000 ppmv or more, 20,000 ppmv or more, or 40,000 ppmv or more, preferably, 10,000 to 120,000 ppmv, 10,000 to 110,000 ppmv, or 10,000 to 100,000 ppmv. According to Table 2 above, when the mixing ratio of CF3OCFCF2 is below 70 mol%, the acute inhalation toxicity level 4 upper limit (LC 50 =20,000ppmv), so it can be classified as toxicity level 4 or above.

[0069] In order to detect the insulation endurance according to the mixing ratio of the mixed gas of CF3OCFCF2 and CO2, the same insulation performance test method has been performed on CF3OCFCF2.

[0070] Figure 4 The graph of the Paschen curve for the 50% discharge voltage of the mixed gas of CF3OCFCF2 and CO2 with different mixing ratios is shown. Here, 5mm, 8mm and 11mm refer to the 50% discharge voltage when the distance between the ball-to-plate electrodes is set to 5mm, 8mm and 11mm respectively for the mixed gas of CF3OCFCF2 and CO2, and the 50% discharge voltage when the distance between the ball-to-plate electrodes is set to 5mm, 8mm and 11mm respectively for the mixed gas of SF6 and g 3The 50% discharge voltage of each when the distance between the ball and the plate electrode is 5 mm. Based on this, it is confirmed that for the mixed gas of CF3OCFCF2 and CO2, the 50% discharge voltage table shows a nonlinear graph depending on the mixing ratio, and the insulation endurance is 87% to 130% compared with SF6.

[0071] Specifically, the mixed gas of CF3OCFCF2 and CO2 is, when the distance between the electrodes is 8mm and 11mm, no matter what the mixing ratio of CF3OCFCF2 is, the 50% discharge voltage is higher than that of SF6 and g 3 Moreover, it can be seen that except for the case where the distance between the electrodes is relatively small (5 mm) and the mixing ratio of CF3OCFCF2 is low (10 to 23 mol%), the 50% discharge voltage is higher than that of SF6 and g 3 In particular, when the mixing ratio of CF3OCFCF2 is 30 mol%, the 50% discharge voltage is 113% higher than that of SF6 and 113% higher than that of g 3 Gas Excellent 126%.

[0072] Figure 6 This is a graph showing the results of the 50% discharge voltage test (IEC 60060-1 lightning impulse test) of a mixed gas of CF3OCCF2 and CO2 with a varying mixing ratio and SF6. The test electrode used a Rogowski profile (electric field utilization factor 0.94 to 1), and the 50% discharge voltage was tested at atmospheric pressure with the distance between the flat plates set to 5mm, 8mm, 11mm, and 15mm.

[0073] The experimental results show that the insulation endurance of a mixed gas of CF3OCFCF2 5% and CO2 95% is 66% to 72% compared with SF6; the insulation endurance of a mixed gas of CF3OCFCF2 10% and CO2 90% is 78% to 94% compared with SF6. It can be confirmed that the insulating gas of the present invention can replace SF6.

[0074] In the insulating gas of the present invention, the synergistic effect may be greater than -0.1, greater than -0.08, or greater than -0.05. Figure 5 This is a graph showing the insulation resistance synergy effect according to the mixing ratio of CF3OCFCF2. The insulation resistance synergy effect C is obtained by the following mathematical formula 1:

[0075] (Mathematical formula 1)

[0076]

[0077] In the mathematical formula 1, k is the mixing ratio (mol %) of the trifluoromethyl trifluorovinyl ether, Vm is the dielectric breakdown voltage of the mixed gas, Va is the dielectric breakdown voltage of trifluoromethyl trifluorovinyl ether, and Vb is the dielectric breakdown voltage of the carrier gas.

[0078] according to Figure 5 , according to the mixing ratio of CF3OCFCF2, the insulation endurance synergistic effect presents a nonlinear graph. Specifically, when the mixing ratio of CF3OCFCF2 is in the range of 25 to 58 mol%, the insulation endurance synergistic effect C is above 0; when the mixing ratio of CF3OCFCF2 is 20 to 60 mol%, the insulation endurance synergistic effect C value is above -0.05; when the mixing ratio of CF3OCFCF2 is 10 to 62 mol%, the insulation endurance synergistic effect C value has a value above -0.1. In addition, for the portion below 10 mol%, it is reasonable to speculate that the insulation endurance synergistic effect value has a value above -0.1 or above -0.08. At this time, when the insulation endurance synergistic effect value is equivalent to a value of -, such as Figure 4 As shown in the figure, it can be confirmed that the 50% discharge voltage is higher than that of SF6 or g 3 gas.

[0079] On the other hand, insulating gases used in electrical devices for electrical insulation or arc extinguishing shall not fall into the category of flammable gases. According to KS B ISO 10156:2017, the standards for flammable gases refer to the following table:

[0080] (Table 3)

[0081] Standards for flammable gases

[0082]

[0083] The results of the lower flammable limit (LFL) calculated based on the mixing ratio of CF3OCFCF2 in the mixed gas of CF3OCFCF2 and CO2 are shown in the following table. Here, for the lower flammable limit, when the combustible gas is mixed with air and ignites, the concentration range that can cause flame propagation is expressed by volume concentration (vol%), and the lower flammable limit refers to the minimum value in this volume concentration.

[0084] (Table 4)

[0085] The lower flammable limit of the mixing ratio of CF3OCFCF2 in the mixed gas of CF3OCFCF2 and CO2

[0086] <![CDATA[Mixing ratio of CF3OCFCF2]]> 100 90 80 70 60 50 40 30 Lower flammable limit (LFL) 7.5 8.37 9.47 10.9 12.84 15.61 19.89 27.36

[0087] According to the above experiments, it can be known that when the mixing ratio of CF3OCFCF2 is below 60%, it exceeds the scope of combustible gas category 1.

[0088] On the other hand, it is preferred that the insulating gas does not react with electrodes or housings used in electrical devices for electrical insulation or arc extinguishing.

[0089] When CF3OCFCF2 is used alone as an insulating gas, it reacts with the electrode under atmospheric pressure to form a carbon film. However, when the mixing ratio of CF3OCFCF2 in the mixed gas of CF3OCFCF2 and CO2 is less than 70%, it does not react with the electrode.

[0090] Here, the reactivity test is to confirm whether the electrode reacts during the insulation endurance test at RT (room temperature) and standard pressure 1atm in a sealed space (insulation test chamber) where external gas cannot enter, according to the mixing ratio of the insulating gas. At this time, the material of the ball electrode is CuCr and Wcu, and the material of the plate electrode is CuCr and SUS.

[0091] Therefore, in the case of a mixed gas of CF3OCCF2 and CO2, the mixing ratio of CF3OCCF2 may be 1 to 60 mol%, 3 to 60 mol%, or 5 to 60 mol%, more preferably, 1 to 20 mol%, 3 to 15 mol%, or 5 to 10 mol%, and the remainder may be CO2. Within the above range, the global warming factor (GWP) and insulation resistance are excellent, the possibility of flame propagation is low, and it does not react with electrodes and SUS used in electrical devices for electrical insulation or arc extinguishing, so it is confirmed to be suitable as a gas to replace SF6.

[0092] According to the present invention, SF6 gas designated as a greenhouse gas is replaced by a mixed gas of CF3OCFCF2 and CO2, thereby maintaining insulation performance while having a low global warming index compared to using SF6 gas, thereby reducing harmful effects on the environment.

[0093] On the other hand, the analysis results of the components generated after the arc extinguishing of CF3OCFCF2 showed that trifluoromethane (CHF3), hexafluoroethane (C2F6), tetrafluoroethylene (C2F4), octafluoropropane (C3F8), hexafluoropropylene (C3F6), perfluoro-n-butane (C4F 10 ) etc., and it can be confirmed that these substances produce carbon compounds.

[0094] The use of O2 can effectively reduce or avoid the toxic byproducts of carbides produced after arc extinguishing.

[0095] In this regard, the carrier gas of the present invention may be CO2 and O2.

[0096] In the case where the carrier gas of the insulating gas of the present invention is CO2 and O2, for the total content of CF3OCFCF2, CO2 and O2 is 100%, the mole % of CF3OCFCF2 is x, the mole % of CO2 is y, and the mole % of O2 is z, such as Figure 7 When presented on a triangular diagram, x, y, and z are outside the area enclosed by lines AB, BC, and CA. Figure 7 As shown, this means that it is outside the explosion area represented by triangle ABC.

[0097] Here, straight line AB is a straight line connecting point A and point B, straight line BC is a straight line connecting point B and point C, straight line CA is a straight line connecting point C and point A, x, y, z of point A are 50, 0, 50, x, y, z of point B are 5.1, 0, 94.9, and x, y, z of point C may be 8.2, 80, 11.8. In contrast, when x, y, z exist within triangle ABC (explosion triangle) formed by points A, B, and C, there may be an explosion hazard due to flammability.

[0098] exist Figure 7 In the figure, the explosion limit represents the explosion boundary, which is the line connecting the critical explosion points (filled quadrilateral points). In contrast, the non-ignition point (hollow quadrilateral point) represents the non-ignition point. The coordinates of the critical explosion point and the non-ignition point are shown in Table 5:

[0099] (Table 5)

[0100]

[0101] In addition, Figure 7 Point A of the triangle diagram represents the upper flammability limit (UFL), and is connected to point C, which is the end point on the explosion boundary, to form an expected explosion limit (expected line), that is, straight line AC. Thus, the explosion triangle ABC can be formed by connecting the end points on the explosion boundary, that is, point B, point C and point A, and it is confirmed that non-flammability can be achieved when the composition of the insulating gas exists outside the explosion triangle. On the other hand, the ICR line on the triangle diagram is a tangent to the explosion triangle passing through O2 100%, and the MXC value is 9.3% (C3F6O in CO2).

[0102] More specifically, the carrier gas is CO2 and O2, and for the mixed gas, the mixing ratio of CF3OCFCF2 is 1 to 60 mol%, the mixing ratio of O2 is 1 to 30 mol%, and the remainder may be CO2. In terms of insulation and safety, it is more preferred that the mixing ratio of CF3OCFCF2 is 3 to 20 mol%, 4 to 16 mol%, or 5 to 10 mol%, the mixing ratio of O2 is 1 to 30 mol%, 1 to 25 mol%, or 1 to 20 mol%, and the remainder may be CO2.

[0103] When the molar ratio of CF3OCFCF2 exceeds the range, the synergistic effect or safety may be reduced. On the contrary, when the molar ratio of O2 does not reach the range, it may be difficult to effectively exert the insulation performance. In addition, when the molar ratio of O2 exceeds the range, the flammability is improved. On the contrary, when the molar ratio of O2 does not reach the range, the effect of reducing the toxic byproducts of the carbon compound may be reduced.

[0104] Then, in the case where the carrier gas is CO2 and O2, the molar ratio of CO2 to O2 may be 70:30 to 99:1, 80:20 to 95:5, or 85:15 to 90:10. When the mixed molar ratio of O2 exceeds the range compared to CO2, the combustibility is improved, and conversely, when the range is not reached, the toxic byproduct reduction effect of the carbon compound may be reduced.

[0105] In addition, according to a preferred embodiment of the present invention, in addition to the mixed gas of CF3OCFCF2 and CO2 containing pure O2, a gas mixture containing O2, especially air containing O2, can also be used.

[0106] On the other hand, an electrical device according to another aspect of the present invention is electrically insulated or arc extinguished by an insulating gas, and the insulating gas of the above embodiment can be used for insulation or arc extinguishing.

[0107] Examples of such electrical devices include gas transmission lines, gas insulated switchgear, RMU (ring main unit), DC protection equipment, and power distribution systems. They can also be used in new and renewable energy such as sunlight and wind power, long-distance power transmission, and emergency power supply devices.

[0108] The high voltage circuit breaker and gas insulated switchgear using the insulating gas of the present invention are applicable to high voltages of 72.5 to 800 kV and medium voltages of 1 to 72.5 kV, and are particularly suitable for high voltage areas.

[0109] The electrical device of the present invention (for example, a high voltage circuit breaker or a gas insulated switchgear) comprises: an insulating space filled with the insulating gas of the present invention inside a casing; and a conductive component arranged inside the casing.

[0110] At this time, the temperature outside the housing may be -35 to 55° C., -30 to 50° C., or -25 to 40° C., and the 24-hour average temperature may be about 35° C. In addition, the pressure of the insulating space may be 1.5 MPaG, 1.2 MPaG, or less than 0.9 MPaG, and the voltage provided to the conductive component may be 1 to 1100 kV, 1 to 1000 kV, or 1 to 800 kV.

[0111] Although specific embodiments of the present invention have been described above mainly with reference to the drawings, it is obvious that the scope of rights of the present invention includes modifications or equivalents centered around the technical ideas described in the claims.

Claims

1. An insulating gas used for electrical insulation or arc extinguishing of electrical devices, characterized in that: The insulating gas is a mixture of trifluoromethyl trifluorovinyl ether (CF3OCFCF2) and a carrier gas. For the mixed gas and SF6, the distance between the ball-to-plate electrodes is set to 5 mm and the 50% discharge voltage is detected. Here, for the mixed gas, when the mixing ratio is changed for detection, there is a region where the discharge voltage of the mixed gas is higher than the mixing ratio of SF6.

2. An insulating gas used for electrical insulation or arc extinguishing of electrical devices, characterized in that: The insulating gas is a mixture of trifluoromethyl trifluorovinyl ether (CF3OCFCF2) and a carrier gas. When the mixing ratio of the mixed gas was changed and the distance between the ball-to-plate electrodes was set to 8 mm to detect the 50% discharge voltage, the peak of the discharge voltage existed in the region where the mixing ratio of the trifluoromethyl trifluorovinyl ether was 70% or less.

3. The insulating gas according to claim 1 or 2, characterized in that: The 50% discharge voltage of the mixed gas presents a nonlinear graph according to the mixing ratio thereof.

4. The insulating gas according to claim 1 or 2, characterized in that: The mixed gas is, A mixing ratio (k) such that the dielectric strength synergy effect (C) defined by the following mathematical formula 1 is greater than -0.1, Mathematical formula 1: In the mathematical formula 1, k is the mixing ratio (mol %) of the trifluoromethyl trifluorovinyl ether, Vm is the dielectric breakdown voltage of the mixed gas, Va is the dielectric breakdown voltage of trifluoromethyl trifluorovinyl ether, and Vb is the dielectric breakdown voltage of the carrier gas.

5. The insulating gas according to claim 4, characterized in that The carrier gas is CO2, In the mixed gas, the mixing ratio of CF3OCFCF2 is 1 to 60 mol %.

6. The insulating gas according to claim 4, characterized in that The carrier gas is CO2 and O2, The mole % of CF3OCFCF2 is x, the mole % of CO2 is y, and the mole % of O2 is z. When presented on a triangular graph, x, y, and z are outside the area surrounded by straight lines AB, BC, and CA. The straight line AB is a straight line connecting point A and point B, the straight line BC is a straight line connecting point B and point C, and the straight line CA is a straight line connecting point C and point A; the x, y, and z of point A are 50, 0, and 50, the x, y, and z of point B are 5.1, 0, and 94.9, and the x, y, and z of point C can be 8.2, 80, and 11.

8.

7. The insulating gas according to claim 4, characterized in that The carrier gas is CO2 and O2, The mixed gas is composed of CF3OCFCF2 in a mixing ratio of 1 to 60 mol%, O2 in a mixing ratio of 1 to 30 mol%, and the remainder is CO2.

8. The insulating gas according to claim 4, characterized in that The discharge voltage is detected under atmospheric pressure.

9. An electrical device, which is electrically insulated or arc extinguished by insulating gas, characterized in that: Utilize the insulating gas of claim 1 or 2.

10. The electrical device according to claim 9, characterized in that include: an insulating space filled with the insulating gas inside the housing; and A conductive component is disposed inside the housing.

Images