Method and system for measuring liquefaction temperature of multi-element environment-friendly mixed insulating gas

Abstract

The invention discloses a method and a system for measuring the liquefaction temperature of multi-element environment-friendly mixed insulating gas. The method comprises the following steps: acquiring various multi-element environment-friendly mixed insulating gases; the composition of each multi-element environment-friendly mixed insulating gas is obtained, and the volume ratio of each component is obtained; testing each multi-element environment-friendly mixed insulating gas to obtain a saturated vapor pressure P-T curve of the main environment-friendly insulating gas, and determining a saturated vapor pressure equation of the main environment-friendly insulating gas based on the curve; determining a buffer gas pressure equation of the buffer gas based on the ideal state equation of the buffer gas; determining an equilibrium relational expression based on a gas-liquid two-phase equilibrium basic law; determining a multi-element environment-friendly mixed insulating gas state equation based on the saturated vapor pressure equation of the main environment-friendly insulating gas, the buffer gas pressure equation of the buffer gas and the balance relational expression; and introducing the gas pressure of the target multi-element environment-friendly mixed insulating gas to be measured into the multi-element environment-friendly mixed insulating gas state equation so as to determine the liquefaction temperature of the target multi-element environment-friendly mixed insulating gas.

Description

Technical Field

[0001] The present invention relates to the technical field of environmentally friendly gas-insulated power transmission and distribution equipment, and more specifically, to a method and system for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas. Background Art

[0002] Sulfur hexafluoride (SF6) gas is widely used in electrical equipment because of its excellent insulation and arc extinguishing medium, but its greenhouse effect is 24,300 times that of CO2, and its lifespan in the atmosphere is as long as 3,200 years. Existing studies have shown that environmentally friendly gases such as trifluoromethylsulfonyl fluoride (CF3SO2F) and perfluoroisobutyronitrile (C4F7N) have high insulation strength and low greenhouse effect, and are considered to be potential environmentally friendly alternative gases for SF6 for electrical equipment, and are gradually being applied in engineering equipment. Compared with the physical and chemical properties of SF6 gas, the liquefaction temperature of CF3SO2F and C4F7N is higher, and they need to be mixed with buffer gases such as CO2 and N2 to form a multi-element environmentally friendly mixed gas to meet the ambient temperature requirements of equipment use. Since the ternary environmentally friendly mixed insulating gas composed of CF3SO2F, C4F7N and buffer gas lacks key physical property parameters, it is difficult to obtain its liquefaction temperature, and it is also impossible to determine the ambient temperature applicable to equipment using this type of environmentally friendly mixed gas.

[0003] At present, most people use the method of testing saturated vapor pressure to determine the liquefaction temperature of gas, but this method is only applicable to a single gas and is not applicable to the liquefaction temperature measurement of multi-component mixed gases. Therefore, it is urgent to develop a method for measuring the liquefaction temperature of multi-component environmentally friendly mixed insulating gases. Summary of the invention

[0004] The present invention provides a method and system for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas, so as to solve the problem of how to efficiently and accurately determine the liquefaction temperature of the multi-element environmentally friendly mixed insulating gas.

[0005] In order to solve the above problem, according to one aspect of the present invention, a method for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas is provided, the method comprising:

[0006] Obtaining a plurality of multi-element environmentally friendly mixed insulating gases; wherein the multi-element environmentally friendly mixed insulating gases include: a main environmentally friendly insulating gas and a buffer gas;

[0007] Obtain the composition of each multi-component environmentally friendly mixed insulating gas and the volume percentage of each component;

[0008] Testing each multi-element environmentally friendly mixed insulating gas to obtain a saturated vapor pressure PT curve of the main environmentally friendly insulating gas, and determining a saturated vapor pressure equation of the main environmentally friendly insulating gas based on the saturated vapor pressure PT curve;

[0009] Determine the buffer gas pressure equation of the buffer gas based on the ideal state equation of the buffer gas;

[0010] Determine the equilibrium relationship based on the basic law of gas-liquid two-phase equilibrium;

[0011] Determine a multi-element environmentally friendly mixed insulating gas state equation based on the saturated vapor pressure equation of the main environmentally friendly insulating gas, the buffer gas pressure equation of the buffer gas, and a balance relationship;

[0012] The gas pressure of the target multi-element environmentally friendly mixed insulating gas to be measured is substituted into the multi-element environmentally friendly mixed insulating gas state equation to determine the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas.

[0013] Preferably, the volume proportion of the main environmentally friendly insulating gas is less than or equal to 20%; the main environmentally friendly insulating gas includes: trifluoromethylsulfonyl fluoride CF3SO2F and perfluoroisobutyronitrile C4F7N; the buffer gas includes: carbon dioxide CO2 or nitrogen N2.

[0014] Preferably, the saturated vapor pressure equation of the main environmentally friendly insulating gas includes:

[0015]

[0016] Where p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature.

[0017] Preferably, the buffer gas pressure equation of the buffer gas includes:

[0018] p3(T)=3.41*10 -6 pk3T,

[0019] Among them, p3(T) is the buffer gas pressure; p is the pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k3 is the volume percentage of the buffer gas; T is the temperature.

[0020] Preferably, the equilibrium relationship comprises:

[0021]

[0022] Among them, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature; f1 and f2 are the volume proportions of the gas-liquid phase of CF3SO2F and C4F7N respectively; p3(T) is the buffer gas pressure; k1, k2 and k3 are the volume proportions of CF3SO2F, C4F7N and buffer gas respectively; p(T) is the pressure of the multi-component environmentally friendly mixed insulating gas at temperature T.

[0023] Preferably, the multivariate environmentally friendly mixed insulating gas state equation includes:

[0024]

[0025] Among them, p(T) is the gas pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k1 and k2 are the volume proportions of CF3SO2F and C4F7N respectively; T1 is the liquefaction temperature.

[0026] Preferably, the method further comprises:

[0027] When the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas is greater than the preset temperature, it is suggested to reduce the volume ratio of C4F7N gas so that the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas meets the requirements.

[0028] According to another aspect of the present invention, a system for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas is provided, the system comprising:

[0029] A multi-element environmentally friendly mixed insulating gas acquisition unit is used to acquire a plurality of multi-element environmentally friendly mixed insulating gases; wherein the multi-element environmentally friendly mixed insulating gas includes: a main environmentally friendly insulating gas and a buffer gas;

[0030] A component testing unit is used to obtain the composition of each multi-component environmentally friendly mixed insulating gas and the volume percentage of each component;

[0031] A saturated vapor pressure equation determination unit, used to test each multi-element environmentally friendly mixed insulating gas, obtain a saturated vapor pressure PT curve of the main environmentally friendly insulating gas, and determine the saturated vapor pressure equation of the main environmentally friendly insulating gas based on the saturated vapor pressure PT curve;

[0032] a buffer gas pressure equation determining unit, used for determining a buffer gas pressure equation of the buffer gas based on an ideal state equation of the buffer gas;

[0033] An equilibrium relationship determination unit, used for determining the equilibrium relationship based on the basic law of gas-liquid two-phase equilibrium;

[0034] A state equation determination unit, used to determine a multivariate environmentally friendly mixed insulating gas state equation based on the saturated vapor pressure equation of the main environmentally friendly insulating gas, the buffer gas pressure equation of the buffer gas, and a balance relationship;

[0035] The liquefaction temperature determination unit is used to bring the gas pressure of the target multi-component environmentally friendly mixed insulating gas to be measured into the state equation of the multi-component environmentally friendly mixed insulating gas to determine the liquefaction temperature of the target multi-component environmentally friendly mixed insulating gas.

[0036] Preferably, the volume proportion of the main environmentally friendly insulating gas is less than or equal to 20%; the main environmentally friendly insulating gas includes: trifluoromethylsulfonyl fluoride CF3SO2F and perfluoroisobutyronitrile C4F7N; the buffer gas includes: carbon dioxide CO2 or nitrogen N2.

[0037] Preferably, the saturated vapor pressure equation of the main environmentally friendly insulating gas includes:

[0038]

[0039] Where p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature.

[0040] Preferably, the buffer gas pressure equation of the buffer gas includes:

[0041] p3(T)=3.41*10 -6 pk3T,

[0042] Among them, p3(T) is the buffer gas pressure; p is the pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k3 is the volume percentage of the buffer gas; T is the temperature.

[0043] Preferably, the equilibrium relationship comprises:

[0044]

[0045] Among them, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature; f1 and f2 are the volume proportions of the gas-liquid phase of CF3SO2F and C4F7N respectively; p3(T) is the buffer gas pressure; k1, k2 and k3 are the volume proportions of CF3SO2F, C4F7N and buffer gas respectively; p(T) is the pressure of the multi-component environmentally friendly mixed insulating gas at temperature T.

[0046] Preferably, the multivariate environmentally friendly mixed insulating gas state equation includes:

[0047]

[0048] Among them, p(T) is the gas pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k1 and k2 are the volume proportions of CF3SO2F and C4F7N respectively; T1 is the liquefaction temperature.

[0049] Preferably, the system further comprises:

[0050] The judgment unit is used to prompt to reduce the volume ratio of C4F7N gas when the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas is greater than a preset temperature, so that the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas meets the requirements.

[0051] The present invention provides a method and system for measuring the liquefaction temperature of a multi-component environmentally friendly mixed insulating gas, comprising: obtaining a plurality of multi-component environmentally friendly mixed insulating gases; wherein the multi-component environmentally friendly mixed insulating gas comprises: a main environmentally friendly insulating gas and a buffer gas; obtaining the composition of each multi-component environmentally friendly mixed insulating gas, and obtaining the volume proportion of each component; testing each multi-component environmentally friendly mixed insulating gas, obtaining a saturated vapor pressure PT curve of the main environmentally friendly insulating gas, and determining the saturated vapor pressure equation of the main environmentally friendly insulating gas based on the saturated vapor pressure PT curve; determining the buffer gas pressure equation of the buffer gas based on an ideal state equation of the buffer gas; determining an equilibrium relationship based on the basic law of gas-liquid two-phase equilibrium; determining a multi-component environmentally friendly mixed insulating gas state equation based on the saturated vapor pressure equation of the main environmentally friendly insulating gas, the buffer gas pressure equation of the buffer gas and the equilibrium relationship; bringing the gas pressure of the target multi-component environmentally friendly mixed insulating gas to be measured into the multi-component environmentally friendly mixed insulating gas state equation to determine the liquefaction temperature of the target multi-component environmentally friendly mixed insulating gas. The present invention measures the saturated vapor pressure of each gas, CF3SO2F and C4F7N, thereby avoiding the deficiency of directly measuring the saturated vapor pressure of the mixed gas; adopts an engineering processing method of describing the PT curve of CO2 or N2 using an ideal state equation, better considering the influence of the buffer gas characteristics on the liquefaction temperature of the mixed gas, and the measurement and calculation process is relatively engineering and not cumbersome, thereby ensuring that the obtained liquefaction temperature can meet the use requirements of this type of environmental protection equipment, and can provide important support for the research and development of environmental protection gas transmission and distribution equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0053] Figure 1 It is a flow chart of a method 100 for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas according to an embodiment of the present invention;

[0054] Figure 2 is a schematic diagram of a saturated vapor pressure measuring device according to an embodiment of the present invention;

[0055] Figure 3 A schematic diagram of a CF3SO2F saturated vapor pressure curve according to an embodiment of the present invention;

[0056] Figure 4 A schematic diagram of a saturated vapor pressure curve of C4F7N according to an embodiment of the present invention;

[0057] Figure 5 Schematic diagram of the structure of a liquefaction temperature measurement system 500 for a multi-element environmentally friendly mixed insulating gas according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0059] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0060] Figure 1 FIG. 1 is a flow chart of a method 100 for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas according to an embodiment of the present invention. Figure 1 As shown, the method for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas provided in an embodiment of the present invention measures the saturated vapor pressure of each of the two gases CF3SO2F and C4F7N, avoiding the deficiency of directly measuring the saturated vapor pressure of the mixed gas; the engineering processing method using the ideal state equation to describe the PT curve of CO2 or N2 better considers the influence of the buffer gas characteristics on the liquefaction temperature of the mixed gas, and the measurement and calculation process is engineering-oriented and not cumbersome, ensuring that the obtained liquefaction temperature can meet the use requirements of this type of environmental protection equipment, and can provide important support for the research and development of environmentally friendly gas transmission and distribution equipment. The method 100 for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas provided in an embodiment of the present invention starts from step 101. In step 101, a plurality of multi-element environmentally friendly mixed insulating gases are obtained; wherein the multi-element environmentally friendly mixed insulating gas includes: a main environmentally friendly insulating gas and a buffer gas.

[0061] Preferably, the volume proportion of the main environmentally friendly insulating gas is less than or equal to 20%; the main environmentally friendly insulating gas includes: trifluoromethylsulfonyl fluoride CF3SO2F and perfluoroisobutyronitrile C4F7N; the buffer gas includes: carbon dioxide CO2 or nitrogen N2.

[0062] In the present invention, a ternary environmentally friendly mixed insulating gas is formed by two main environmentally friendly insulating gases, trifluoromethylsulfonyl fluoride (CF3SO2F) and perfluoroisobutyronitrile (C4F7N), and buffer gases such as CO2 and N2. The mixed gas pressure p is 0.5-0.8MPa, and the volume proportion k of the main environmentally friendly insulating gas is not more than 20%.

[0063] In step 102, the composition of each multi-component environmentally friendly mixed insulating gas is obtained, and the volume percentage of each component is obtained.

[0064] In the present invention, a gas chromatography-mass spectrometry (GC-MS) method is used to test the composition of each multi-element environmentally friendly mixed insulating gas, and the volume proportion k1 of CF3SO2F, the volume proportion k2 of C4F7N, and the buffer gas of CO2 or N2 and its volume proportion k3 are obtained.

[0065] In step 103, each multi-element environmentally friendly mixed insulating gas is tested to obtain a saturated vapor pressure PT curve of the main environmentally friendly insulating gas, and a saturated vapor pressure equation of the main environmentally friendly insulating gas is determined based on the saturated vapor pressure PT curve.

[0066] Preferably, the saturated vapor pressure equation of the main environmentally friendly insulating gas includes:

[0067]

[0068] Where p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature.

[0069] In the present invention, referring to the requirements of GB / T 42426-2023 "Chemical Vapor Pressure Test", the saturated vapor pressure PT curve of CF3SO2F and C4F7N gas is tested by static method, and the saturated vapor pressure equation of CF3SO2F and C4F7N gas is obtained based on the PT curve:

[0070]

[0071] Wherein, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively, in kPa; T is the temperature, in K. The applicable temperature range of formula (1) is 243.15~373.15K.

[0072] In step 104, a buffer gas pressure equation of the buffer gas is determined based on an ideal state equation of the buffer gas.

[0073] Preferably, the buffer gas pressure equation of the buffer gas includes:

[0074] p3(T)=3.41*10 -6 pk3T,

[0075] Among them, p3(T) is the buffer gas pressure; p is the pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k3 is the volume percentage of the buffer gas; T is the temperature.

[0076] In the present invention, for the buffer gas CO2 or N2, the PT curve satisfies the ideal state equation:

[0077]

[0078] In the formula, p3(T) is the buffer gas pressure, n is the number of gas moles, V is the gas volume, and R is a constant of 8.314. When the initial temperature T is 20°C, p3 is p*k3, so based on formula (2), it can be calculated as follows:

[0079] p3(T)=3.41*10 -6 pk3T(3)

[0080] Among them, p3(T) is the buffer gas pressure; p is the pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k3 is the volume percentage of the buffer gas; T is the temperature.

[0081] In step 105, an equilibrium relationship is determined based on the basic law of gas-liquid two-phase equilibrium.

[0082] Preferably, the equilibrium relationship comprises:

[0083]

[0084] Among them, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature; f1 and f2 are the volume proportions of the gas-liquid phase of CF3SO2F and C4F7N respectively; p3(T) is the buffer gas pressure; k1, k2 and k3 are the volume proportions of CF3SO2F, C4F7N and buffer gas respectively; p(T) is the pressure of the multi-component environmentally friendly mixed insulating gas at temperature T.

[0085] In the present invention, according to the basic law of gas-liquid two-phase equilibrium, we obtain:

[0086]

[0087] In the formula, f1 and f2 are the volume proportions of CF3SO2F and C4F7N gas liquid phases respectively. It can be calculated from formula (4):

[0088]

[0089] In step 106, a multi-element environmentally friendly mixed insulating gas state equation is determined based on the saturated vapor pressure equation of the main environmentally friendly insulating gas, the buffer gas pressure equation of the buffer gas, and a balance relationship.

[0090] Preferably, the multivariate environmentally friendly mixed insulating gas state equation includes:

[0091]

[0092] Among them, p(T) is the gas pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k1 and k2 are the volume proportions of CF3SO2F and C4F7N respectively; T1 is the liquefaction temperature.

[0093] In step 107, the gas pressure of the target multi-element environmentally friendly mixed insulating gas to be measured is substituted into the multi-element environmentally friendly mixed insulating gas state equation to determine the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas.

[0094] In the present invention, by combining equation (1), equation (3) and equation (5), the state equation of the environmentally friendly mixed gas can be obtained as follows:

[0095]

[0096] When determining the liquefaction temperature, first determine the gas pressure p(T) of the target multi-element environmentally friendly mixed insulating gas to be measured at 20°C, and substitute p(T) into formula (6) to calculate the corresponding liquefaction temperature T1.

[0097] Preferably, the method further comprises:

[0098] When the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas is greater than the preset temperature, it is suggested to reduce the volume ratio of C4F7N gas so that the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas meets the requirements.

[0099] In the present invention, if the target liquefaction temperature T of the multi-element environmentally friendly mixed insulating gas is greater than 258.15K, it is determined that the volume proportion k2 of the C4F7N gas should be reduced to ensure that the liquefaction temperature of the multi-element environmentally friendly mixed insulating gas is not higher than -15°C.

[0100] The following specifically illustrates the embodiments of the present invention.

[0101] In an embodiment of the present invention, the process of determining the liquefaction temperature of the multi-element environmentally friendly mixed insulating gas includes:

[0102] Step 1: Trifluoromethylsulfonyl fluoride (CF3SO2F) and perfluoroisobutyronitrile (C4F7N) are used as two main environmentally friendly insulating gases and buffer gases such as CO2 and N2 to form a ternary environmentally friendly mixed insulating gas, and the mixed gas pressure p is 0.5-0.8MPa, wherein the volume proportion k of the main environmentally friendly insulating gas is not greater than 20%. CF3SO2F, C4F7N, and CO2 form a ternary environmentally friendly mixed gas insulating gas, and the mixed gas pressure is 0.6MPa.

[0103] Step 2, using gas chromatography-mass spectrometry (GC-MS) method to test the composition of the environmentally friendly mixed gas, the volume proportion k1 of CF3SO2F is 20%, the volume proportion k2 of C4F7N is 6%, and the volume proportion k3 of the buffer gas CO2 is 74%.

[0104] Step 3, refer to GB / T 42426-2023 "Chemical Vapor Pressure Test" requirements, saturated vapor pressure measuring device such as Figure 2 As shown in the figure, 1 is the sample tank; 2 is the temperature sensor; 3 is the pressure sensor; 4 is the vacuum pump; 5 is the sample to be tested; 6 is the computer; and 7 is the constant temperature circulation device. The saturated vapor pressure PT curves of CF3SO2F and C4F7N gases are tested by the static method, as shown in the figure below. Figure 3 and Figure 4 Then, the saturated vapor pressure equation of CF3SO2F and C4F7N gas is fitted as follows:

[0105]

[0106] Wherein, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively, in kPa; T is the temperature, in K. The applicable temperature range of formula (1) is 243.15~373.15K.

[0107] Step 4, for the buffer gas CO2 or N2, the PT curve satisfies the ideal state equation:

[0108]

[0109] In the formula, p3(T) is the buffer gas pressure, n is the number of gas moles, V is the gas volume, and R is a constant of 8.314. The calculation results are:

[0110] p3(T)=0.0015T(3)

[0111] Step 5, according to the basic law of gas-liquid two-phase equilibrium, we get:

[0112]

[0113] In the formula, f1 and f2 are the volume proportions of CF3SO2F and C4F7N gas liquid phases respectively. Calculated by formula (4):

[0114]

[0115] Step 6, combining equation (1), equation (3) and equation (5), the environmentally friendly mixed gas state equation p(T) is obtained as follows:

[0116]

[0117] Step 7: When the mixed gas pressure p(T) is 0.6 MPa, substitute it into formula (6) and calculate that its liquefaction temperature is -23°C. Therefore, there is no need to adjust the composition of the mixed gas, and the requirement that the ambient temperature of the equipment is not higher than -15°C has been met.

[0118] The present invention provides a method for measuring the liquefaction temperature of a multi-component environmentally friendly mixed insulating gas. The method adopts a method combining measurement and calculation. The fitting expression of the two gases CF3SO2F and C4F7N is obtained by measuring their respective saturated vapor pressure curves. The state equation expression of the ternary environmentally friendly mixed insulating gas is obtained in combination with the buffer gas state equation according to the gas-liquid two-phase equilibrium law. The liquefaction temperature of the multi-component environmentally friendly mixed gas is obtained by the total saturated vapor pressure of the equipment, which provides important support for the research and development of environmentally friendly gas transmission and distribution equipment.

[0119] Figure 5 FIG. 5 is a schematic diagram of a liquefaction temperature measurement system 500 for a multi-element environmentally friendly mixed insulating gas according to an embodiment of the present invention. Figure 5 As shown, the liquefaction temperature measurement system 500 of the multi-component environmentally friendly mixed insulating gas provided in the embodiment of the present invention includes: a multi-component environmentally friendly mixed insulating gas acquisition unit 501, a component testing unit 502, a saturated vapor pressure equation determination unit 503, a buffer gas pressure equation determination unit 504, an equilibrium relationship determination unit 505, a state equation determination unit 506 and a liquefaction temperature determination unit 507.

[0120] Preferably, the multi-element environmentally friendly mixed insulating gas acquisition unit 501 is used to acquire a plurality of multi-element environmentally friendly mixed insulating gases; wherein the multi-element environmentally friendly mixed insulating gas includes: a main environmentally friendly insulating gas and a buffer gas.

[0121] Preferably, the volume proportion of the main environmentally friendly insulating gas is less than or equal to 20%; the main environmentally friendly insulating gas includes: trifluoromethylsulfonyl fluoride CF3SO2F and perfluoroisobutyronitrile C4F7N; the buffer gas includes: carbon dioxide CO2 or nitrogen N2.

[0122] Preferably, the component testing unit 502 is used to obtain the composition of each multi-component environmentally friendly mixed insulating gas and obtain the volume percentage of each component.

[0123] Preferably, the saturated vapor pressure equation determination unit 503 is used to test each multi-component environmentally friendly mixed insulating gas, obtain the saturated vapor pressure PT curve of the main environmentally friendly insulating gas, and determine the saturated vapor pressure equation of the main environmentally friendly insulating gas based on the saturated vapor pressure PT curve.

[0124] Preferably, the saturated vapor pressure equation of the main environmentally friendly insulating gas includes:

[0125]

[0126] Where p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature.

[0127] Preferably, the buffer gas pressure equation determining unit 504 is used to determine the buffer gas pressure equation of the buffer gas based on the ideal state equation of the buffer gas.

[0128] Preferably, the buffer gas pressure equation of the buffer gas includes:

[0129] p3(T)=3.41*10 -6 pk3T,

[0130] Among them, p3(T) is the buffer gas pressure; p is the pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k3 is the volume percentage of the buffer gas; T is the temperature.

[0131] Preferably, the equilibrium relationship determination unit 505 is used to determine the equilibrium relationship based on the basic law of gas-liquid two-phase equilibrium.

[0132] Preferably, the equilibrium relationship comprises:

[0133]

[0134] Among them, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature; f1 and f2 are the volume proportions of the gas-liquid phase of CF3SO2F and C4F7N respectively; p3(T) is the buffer gas pressure; k1, k2 and k3 are the volume proportions of CF3SO2F, C4F7N and buffer gas respectively; p(T) is the pressure of the multi-component environmentally friendly mixed insulating gas at temperature T.

[0135] Preferably, the state equation determination unit 506 is used to determine the state equation of the multi-element environmentally friendly mixed insulating gas based on the saturated vapor pressure equation of the main environmentally friendly insulating gas, the buffer gas pressure equation of the buffer gas, and the equilibrium relationship.

[0136] Preferably, the multivariate environmentally friendly mixed insulating gas state equation includes:

[0137]

[0138] Among them, p(T) is the gas pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k1 and k2 are the volume proportions of CF3SO2F and C4F7N respectively; T1 is the liquefaction temperature.

[0139] Preferably, the liquefaction temperature determination unit 507 is used to bring the gas pressure of the target multi-component environmentally friendly mixed insulating gas to be measured into the multi-component environmentally friendly mixed insulating gas state equation to determine the liquefaction temperature of the target multi-component environmentally friendly mixed insulating gas.

[0140] Preferably, the system further comprises:

[0141] The judgment unit is used to prompt to reduce the volume ratio of C4F7N gas when the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas is greater than a preset temperature, so that the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas meets the requirements.

[0142] The liquefaction temperature measurement system 500 of the multi-element environmentally friendly mixed insulating gas according to the embodiment of the present invention corresponds to the liquefaction temperature measurement method 100 of the multi-element environmentally friendly mixed insulating gas according to another embodiment of the present invention, and will not be described in detail here.

[0143] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

[0144] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise therein. All references to "a / said / the [means, components, etc.]" are to be openly interpreted as at least one instance of said means, components, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated otherwise.

[0145] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0146] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0147] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0148] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for measuring the liquefaction temperature of a multi-element environmentally friendly mixed insulating gas, characterized in that: The method comprises: Obtaining a plurality of multi-element environmentally friendly mixed insulating gases; wherein the multi-element environmentally friendly mixed insulating gases include: a main environmentally friendly insulating gas and a buffer gas; Obtain the composition of each multi-component environmentally friendly mixed insulating gas and the volume percentage of each component; Testing each multi-element environmentally friendly mixed insulating gas to obtain a saturated vapor pressure PT curve of the main environmentally friendly insulating gas, and determining a saturated vapor pressure equation of the main environmentally friendly insulating gas based on the saturated vapor pressure PT curve; Determine the buffer gas pressure equation of the buffer gas based on the ideal state equation of the buffer gas; Determine the equilibrium relationship based on the basic law of gas-liquid two-phase equilibrium; Determine a multi-element environmentally friendly mixed insulating gas state equation based on the saturated vapor pressure equation of the main environmentally friendly insulating gas, the buffer gas pressure equation of the buffer gas, and a balance relationship; The gas pressure of the target multi-element environmentally friendly mixed insulating gas to be measured is substituted into the state equation of the multi-element environmentally friendly mixed insulating gas to determine the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas.

2. The method according to claim 1, characterized in that The volume proportion of the main environmentally friendly insulating gas is less than or equal to 20%; the main environmentally friendly insulating gas includes: trifluoromethylsulfonyl fluoride CF3SO2F and perfluoroisobutyronitrile C4F7N; the buffer gas includes: carbon dioxide CO2 or nitrogen N2.

3. The method according to claim 2, characterized in that The saturated vapor pressure equation of the main environmentally friendly insulating gas includes: Where p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature.

4. The method according to claim 1, characterized in that: The buffer gas pressure equation for the buffer gas includes: p3(T)=3.41*10 -6 pk3T, Among them, p3(T) is the buffer gas pressure; p is the pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k3 is the volume percentage of the buffer gas; T is the temperature.

5. The method according to claim 2, characterized in that: The equilibrium relationship includes: Among them, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature; f1 and f2 are the volume proportions of the gas-liquid phase of CF3SO2F and C4F7N respectively; p3(T) is the buffer gas pressure; k1, k2 and k3 are the volume proportions of CF3SO2F, C4F7N and buffer gas respectively; p(T) is the pressure of the multi-component environmentally friendly mixed insulating gas at temperature T.

6. The method according to claim 2, characterized in that The multivariate environmentally friendly mixed insulating gas state equation includes: Among them, p(T) is the gas pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k1 and k2 are the volume proportions of CF3SO2F and C4F7N respectively; T1 is the liquefaction temperature.

7. The method according to claim 2, characterized in that The method further comprises: When the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas is greater than the preset temperature, it is suggested to reduce the volume ratio of C4F7N gas so that the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas meets the requirement.

8. A liquefaction temperature measurement system for multi-element environmentally friendly mixed insulating gas, characterized in that: The system comprises: A multi-element environmentally friendly mixed insulating gas acquisition unit is used to acquire a plurality of multi-element environmentally friendly mixed insulating gases; wherein the multi-element environmentally friendly mixed insulating gas includes: a main environmentally friendly insulating gas and a buffer gas; A component testing unit is used to obtain the composition of each multi-component environmentally friendly mixed insulating gas and the volume percentage of each component; A saturated vapor pressure equation determination unit, used to test each multi-element environmentally friendly mixed insulating gas, obtain a saturated vapor pressure PT curve of the main environmentally friendly insulating gas, and determine the saturated vapor pressure equation of the main environmentally friendly insulating gas based on the saturated vapor pressure PT curve; a buffer gas pressure equation determining unit, used for determining a buffer gas pressure equation of the buffer gas based on an ideal state equation of the buffer gas; An equilibrium relationship determination unit, used for determining the equilibrium relationship based on the basic law of gas-liquid two-phase equilibrium; A state equation determination unit, used to determine a multivariate environmentally friendly mixed insulating gas state equation based on the saturated vapor pressure equation of the main environmentally friendly insulating gas, the buffer gas pressure equation of the buffer gas, and a balance relationship; The liquefaction temperature determination unit is used to bring the gas pressure of the target multi-component environmentally friendly mixed insulating gas to be measured into the state equation of the multi-component environmentally friendly mixed insulating gas to determine the liquefaction temperature of the target multi-component environmentally friendly mixed insulating gas.

9. The system according to claim 8, characterized in that The volume proportion of the main environmentally friendly insulating gas is less than or equal to 20%; the main environmentally friendly insulating gas includes: trifluoromethylsulfonyl fluoride CF3SO2F and perfluoroisobutyronitrile C4F7N; the buffer gas includes: carbon dioxide CO2 or nitrogen N2.

10. The system according to claim 9, characterized in that The saturated vapor pressure equation of the main environmentally friendly insulating gas includes: Where p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature.

11. The system according to claim 8, characterized in that The buffer gas pressure equation for the buffer gas includes: p3(T)=3.41*10 -6 pk3T, Among them, p3(T) is the buffer gas pressure; p is the pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k3 is the volume percentage of the buffer gas; T is the temperature.

12. The system according to claim 9, characterized in that The equilibrium relationship includes: Among them, p1(T) and p2(T) are the gas pressures of CF3SO2F and C4F7N respectively; T is the temperature; f1 and f2 are the volume proportions of the gas-liquid phase of CF3SO2F and C4F7N respectively; p3(T) is the buffer gas pressure; k1, k2 and k3 are the volume proportions of CF3SO2F, C4F7N and buffer gas respectively; p(T) is the pressure of the multi-component environmentally friendly mixed insulating gas at temperature T.

13. The system according to claim 9, characterized in that The multivariate environmentally friendly mixed insulating gas state equation includes: Among them, p(T) is the gas pressure of the multi-element environmentally friendly mixed insulating gas at temperature T; k1 and k2 are the volume proportions of CF3SO2F and C4F7N respectively; T1 is the liquefaction temperature.

14. The system according to claim 9, characterized in that The system further comprises: The judgment unit is used to prompt to reduce the volume ratio of C4F7N gas when the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas is greater than a preset temperature, so that the liquefaction temperature of the target multi-element environmentally friendly mixed insulating gas meets the requirements.

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