A method for identifying positive synergistic effect mixed insulation gas based on atomic charge distribution

Abstract

A method for identifying positive cooperating effects in mixed insulating gases based on atomic charge distribution is proposed. This invention addresses the problem that current methods for determining the type of cooperating effects in mixed gases require experimental basis, resulting in high costs and time consumption. A stable structure is constructed for gas molecules A and B, and their interaction configurations. The wave functions of the two gas molecules and the wave functions of the interaction configurations are calculated in relation to the Boltzmann distribution ratio. The electronegativity of the two gas molecules is calculated based on their wave functions. The corresponding atomic charge distributions are calculated based on the wave functions of the three molecules in a neutral state. A linear weighted value of the charge transfer amount of each interaction configuration is calculated based on the Boltzmann distribution ratio. The charge transfer direction is analyzed based on the electronegativity of the two gas molecules and the linear weighted value of each interaction configuration. If the interaction configuration exhibits a characteristic of electron transfer to the less electronegative gas molecule, it is a positive cooperating effect; otherwise, it is a cooperating effect.

Description

Technical Field

[0001] This invention relates to the field of gaseous insulating media, and more specifically to a method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution. Background Technology

[0002] SF6 gas, due to its excellent insulation and physicochemical properties, is widely used in various gas-insulated equipment. However, SF6's global warming potential (GWP) is 24,300 times that of CO2, and its atmospheric lifetime is as long as 3,200 years, meaning it is difficult to decompose naturally, and its environmental pollution is more persistent and significant. Therefore, in addition to GWP, atmospheric lifetime is also a recognized indicator of a gas's environmental impact. Under the current constraints of "dual carbon" targets, finding environmentally friendly insulating gases to replace SF6 is an urgent research topic.

[0003] Mixed insulating gases are an effective alternative to SF6. By mixing electronegative gases with buffer gases (CO2, N2, etc.), the use of greenhouse gases can be significantly reduced. However, compared to pure SF6, the insulating strength of mixed gases is significantly lower, and the insulating strength of mixed gases typically exhibits a non-linear relationship with the mixing ratio. Generally, the breakdown voltage of a mixed gas deviates from the linear weighted value of the breakdown voltages of its individual components. Based on the degree of deviation, it can be classified into four types: linear relationship, synergistic effect, positive synergistic effect, and negative synergistic effect. Among them, the breakdown voltage of mixed gases with a positive synergistic effect deviates the most from the linear weighted value, exceeding the breakdown voltage of any individual component gas, and has great potential to replace SF6. Therefore, identifying insulating gases with a positive synergistic effect is key to the design of high dielectric strength mixed gases.

[0004] When different gases are mixed, interactions occur between the molecules of the two gases. These interactions alter the distribution of outer electrons in the molecules, thereby changing their ability to adsorb electrons, i.e., changing their electronegativity. This change in electronegativity affects the development of electron avalanches during gas discharge, causing a deviation between the dielectric strength of the mixed gas and the linear weighted value of the dielectric strength of a single gas. Therefore, analyzing the charge transfer characteristics before and after the interaction of gas molecules can effectively identify the type of synergistic effect.

[0005] Current methods for determining the type of synergistic effect in mixed gases include breakdown testing and Boltzmann analysis. However, both methods are experimentally based, resulting in high costs and long processing times. Therefore, to efficiently, quickly, and economically determine the type of synergistic effect in mixed gases, this invention proposes a method for identifying mixed insulating gases with positive synergistic effects based on atomic charge distribution. Summary of the Invention

[0006] To address the problem that current methods for determining the type of synergistic effect in mixed gases require experimental basis, resulting in high costs and long processing times, this invention proposes a method for identifying mixed insulating gases with positive synergistic effects based on atomic charge distribution.

[0007] The technical solution adopted in this invention is:

[0008] It includes the following steps:

[0009] Step 1: Construct the initial structures of gas molecule A and gas molecule B respectively, perform geometric optimization and vibration analysis on the initial structures to obtain the stable structures of gas molecule A and gas molecule B respectively, and calculate the wave functions of gas molecule A and gas molecule B in neutral, monovalent cation and monovalent anion states respectively.

[0010] Step 2: Based on the electrostatic potential distribution characteristics of gas molecules A and B, obtain various interaction configurations of gas molecules A and B. The initial structure, for each interaction configuration Geometric optimization and vibration analysis were performed on the initial structure to obtain each interaction configuration. The stable structure was determined, and the interaction configurations were calculated. The ratio of the wave function to the Boltzmann distribution of a stable structure in the neutral state;

[0011] Step 3: Calculate the Mulliken electronegativity of gas molecules A and B based on the wave functions of gas molecules A and B in neutral, monovalent cation, and monovalent anion states.

[0012] Step 4: Based on gas molecule A and gas molecule B in the neutral state and each interaction configuration The wave functions of gas molecules A and B are calculated for each interaction configuration. The atomic charge distribution is determined, and each interaction configuration is calculated based on the Boltzmann distribution ratio. The linear weighted value of the charge transfer amount;

[0013] Step 5: Based on the Mulliken electronegativity of gas molecule A and gas molecule B, and each interaction configuration. Linear weighted values ​​of charge transfer amounts are used to analyze the interaction configurations of gas molecules A and B. The direction of charge transfer, if the interaction configuration If the mixture of gas molecules A and B exhibits a characteristic of electron transfer to less electronegative gas molecules, then the type of cooperative effect is a positive cooperative effect; otherwise, it is a cooperative effect.

[0014] The beneficial effects of this invention are as follows:

[0015] This invention identifies positive synergistic effect mixed insulating gases by calculating the electronegativity and atomic charge transfer direction of the interaction configurations formed by two gas molecules and their combination. If gas molecules exhibit electron transfer characteristics towards the less electronegative gas molecules, the mixed insulating gas macroscopically exhibits a positive synergistic effect. Compared to directly performing gas breakdown experiments to determine the synergistic effect of mixed gases, this method has advantages such as convenience, economy, efficiency, and time saving, and can be used as a preliminary screening and analytical evaluation scheme for mixed insulating gases to assess their insulation performance. Attached Figure Description

[0016] Figure 1 This is a flowchart of the present invention;

[0017] Figure 2 These are schematic diagrams of the charge distribution before and after bonding in the lowest energy configuration of the SF6-HFO interaction configuration, where (a) is a schematic diagram of the charge distribution before bonding and (b) is a schematic diagram of the charge distribution after bonding.

[0018] Figure 3 This is a schematic diagram of the insulation strength curve of SF6 mixed gas; Detailed Implementation

[0019] Specific implementation method one: Combining Figure 1 This embodiment describes a method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution, which includes the following steps:

[0020] Step 1: Construct the initial structures of gas molecule A and gas molecule B respectively. Perform geometric optimization and vibrational analysis on the initial structures to obtain the stable structures of gas molecule A and gas molecule B respectively. Calculate the wave functions of gas molecule A and gas molecule B in neutral, monovalent cation, and monovalent anion states respectively. The specific process is as follows:

[0021] The initial structures of gas molecule A and gas molecule B were constructed using quantum chemical calculation software. Functional and The basis set performs geometric optimization and vibrational analysis on the initial structure, and performs dispersion correction to obtain a stable structure in which gas molecule A is in the ground state and has no imaginary frequency, and a stable structure in which gas molecule B is in the ground state and has no imaginary frequency. The wave functions of gas molecule A in the neutral state, gas molecule A in the monovalent cation state, and gas molecule A in the monovalent anion state are calculated, as well as the wave functions of gas molecule B in the neutral state, gas molecule B in the monovalent cation state, and gas molecule B in the monovalent anion state.

[0022] Step 2: Based on the electrostatic potential distribution characteristics of gas molecules A and B, obtain various interaction configurations of gas molecules A and B. The initial structure, for each interaction configuration Geometric optimization and vibration analysis were performed on the initial structure to obtain each interaction configuration. The stable structure was determined, and the interaction configurations were calculated. The ratio of the wave function to the Boltzmann distribution of a stable structure in the neutral state is as follows:

[0023] Since there are multiple stable bonding modes in the interaction configuration, this invention combines gas molecules A and B based on the electrostatic potential distribution characteristics of gas molecules A and B and utilizes the principle of complementary positive and negative potentials to obtain a variety of interaction configurations. To obtain each interaction configuration The initial structure, utilizing Functional and basis sets for each interaction configuration Geometric optimization and vibration analysis were performed on the initial structure to obtain each interaction configuration. A stable structure in its ground state with no imaginary frequency is calculated, along with the calculation of each interaction configuration. The ratio of the wave function to the Boltzmann distribution of a stable structure in a neutral state.

[0024] The formula for calculating the Boltzmann distribution ratio is as follows:

[0025] (1)

[0026] in, This is the numbering of the interaction configuration. For the first The proportion of each interaction configuration. For the first A molecule with an interacting configuration, It is a natural constant. For the first The difference in energy between each interaction configuration and the lowest energy configuration. It's temperature. It is the ideal gas constant.

[0027] Step 3: Based on the wavefunctions of gas molecules A and B in neutral, monovalent cation, and monovalent anion states, calculate the Mulliken electronegativity of gas molecules A and B. The specific process is as follows:

[0028] The calculation of the Mulliken electronegativity parameter is based on conceptual density functional theory. It uses wavefunctions to calculate the vertical ionization energy and vertical electron affinity of the ground-state molecule, thereby obtaining the first derivative of the molecular energy with respect to the number of electrons, i.e., the Mulliken electronegativity. for:

[0029] (2)

[0030] In the formula, For vertical ionization energy, For vertical electron affinity, For electron energy, This represents the original number of electrons in gas molecule A or gas molecule B. This represents the number of electrons after gas molecule A or gas molecule B ionizes by one electron. The number of electrons after gas molecule A or gas molecule B gains an extra electron.

[0031] Step 4: Based on gas molecule A and gas molecule B in the neutral state and each interaction configuration The wave functions of gas molecules A and B are calculated for each interaction configuration. The atomic charge distribution is determined, and each interaction configuration is calculated based on the Boltzmann distribution ratio. The linear weighted value of the charge transfer amount, the specific process is as follows:

[0032] Based on the wave function of gas molecule A and gas molecule B in the neutral state, and each interaction configuration The wavefunctions of the gas molecules (A, B, and each interaction configuration) are calculated using the Hirshfeld population (ADCH) corrected for atomic dipole moments. First, the atomic space within the gas molecules (A, B, and each interaction configuration) is partitioned using Hirshfeld. After calculating the atomic dipole moments in the gas molecules (A, B, and each interaction configuration) and correcting for the electron density within the atomic space, the atomic charge distributions of the gas molecules (A, B, and each interaction configuration) are calculated. Then, the atomic charge distributions for each interaction configuration are calculated based on the atomic charge distributions of the gas molecules (A, B, and each interaction configuration). Charge transfer amount, depending on each interaction configuration Boltzmann distribution ratio calculation for each interaction configuration Linear weighted value of charge transfer.

[0033] Step 5: Based on the Mulliken electronegativity of gas molecule A and gas molecule B, and each interaction configuration. Linear weighted values ​​of charge transfer amounts are used to analyze the interaction configurations of gas molecules A and B. The direction of charge transfer, if the interaction configuration If the atomic charge distribution exhibits the characteristic of electron transfer to the less electronegative gas molecules, then the type of synergistic effect of the mixed insulating gas (a mixture of gas molecules A and B) is a positive synergistic effect; otherwise, it is a synergistic effect or a linear relationship.

[0034] Example

[0035] Step 1: Construct the initial structures of gas molecules SF6 and HFO using GAUSSVIEW software, and then use GAUSSVIEW software to... At the theoretical level, the initial structure is optimized geometrically and subjected to vibrational analysis, and dispersion correction is performed to obtain the stable structures of gas molecules SF6 and HFO. Then, the wave functions of SF6 and HFO in neutral, monovalent cation and monovalent anion states are calculated.

[0036] Step 2: Based on the complementary positive and negative potential characteristics of SF6 and HFO, construct various interaction configurations. The initial structure was constructed using GAUSSVIEW software. At the theoretical level, for each interaction configuration The initial structure was subjected to geometric optimization and vibration analysis to obtain... The stable structure was determined, and the electron energies of the stable structure were calculated. The wave function and Boltzmann distribution ratio under the neutral state are calculated and the results are shown in Table 1.

[0037] Table 1. Number of configurations and Boltzmann distribution ratio of interacting SF6-HFO

[0038]

[0039] Step 3: Based on the wave functions of SF6 and HFO gas molecules in neutral, monovalent cation, and monovalent anion states, calculate the Mulliken electronegativity of the two gas molecules. The calculation results are shown in Table 2.

[0040] Table 2. Mulliken electronegativity and related parameters of SF6 and HFO gas molecules.

[0041]

[0042] Step 4: Based on SF6, HFO, and each interaction configuration in the neutral state. Given the wavefunction, calculate the charge distribution of each atom in gas molecule A, gas molecule B, and each interaction configuration, where the interaction configuration is... The charge distribution before and after the lowest energy configuration is as follows: Figure 2 As shown. The weighted average charge transfer after the interaction of SF6 and HFO gas molecules is calculated based on the charge distribution results and Boltzmann distribution ratio. .

[0043] Step 5: From Step 3, we can see the difference in electronegativity between SF6 and HFO. Therefore, SF6 gas molecules have a relatively high electronegativity. From step 4, we can see the weighted average of the charge transfer after the interaction between SF6 and HFO gas molecules. It exhibits a significant electron transfer characteristic to the less electronegative gas SF6 molecules, therefore the SF6-HFO mixture is a positive synergistic effect mixed insulating gas.

[0044] To verify the effectiveness of this identification method, five SF6 gas mixtures were calculated using the method described above: SF6 / He, SF6 / N2, SF6 / C3F8, SF6 / OCS, and SF6 / SO2. The positive synergistic effect judgment parameters and results for the five SF6 gas mixtures are shown in Table 3. The experimental results for the five SF6 gas mixtures are as follows: Figure 3 As shown, SF6 / He and SF6 / N2 are synergistic effect gases, while SF6 / C3F8, SF6 / OCS, and SF6 / SO2 are positive synergistic effect gases. The experimental results of the synergistic effect types of the above five SF6 gas mixtures are consistent with the prediction results of this identification method.

[0045] Table 3. Parameters and results for judging the positive synergistic effect of five SF6 gas mixtures.

[0046]

[0047] This invention may have other embodiments. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution, characterized in that: It includes the following steps: Step 1: Construct the initial structures of gas molecule A and gas molecule B respectively, perform geometric optimization and vibration analysis on the initial structures to obtain the stable structures of gas molecule A and gas molecule B respectively, and calculate the wave functions of gas molecule A and gas molecule B in neutral, monovalent cation and monovalent anion states respectively. Step 2: Based on the electrostatic potential distribution characteristics of gas molecules A and B, obtain various interaction configurations of gas molecules A and B. The initial structure, for each interaction configuration Geometric optimization and vibration analysis were performed on the initial structure to obtain each interaction configuration. The stable structure was determined, and the interaction configurations were calculated. The ratio of the wave function to the Boltzmann distribution of a stable structure in the neutral state; Step 3: Calculate the Mulliken electronegativity of gas molecules A and B based on the wave functions of gas molecules A and B in neutral, monovalent cation, and monovalent anion states. Step 4: Based on gas molecule A and gas molecule B in the neutral state and each interaction configuration The wave functions of gas molecules A and B are calculated for each interaction configuration. The atomic charge distribution is determined, and each interaction configuration is calculated based on the Boltzmann distribution ratio. The linear weighted value of the charge transfer amount; Step 5: Based on the Mulliken electronegativity of gas molecule A and gas molecule B, and each interaction configuration. Linear weighted values ​​of charge transfer amounts are used to analyze the interaction configurations of gas molecules A and B. The direction of charge transfer, if the interaction configuration If the mixture of gas molecules A and B exhibits a characteristic of electron transfer to less electronegative gas molecules, then the type of cooperative effect is a positive cooperative effect; otherwise, it is a cooperative effect.

2. The method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution according to claim 1, characterized in that: The specific process of step 1 is as follows: The initial structures of gas molecule A and gas molecule B were constructed using quantum chemical calculation software. Functional and The basis set performs geometric optimization and vibrational analysis on the initial structure to obtain a stable structure in which gas molecule A is in the ground state and has no imaginary frequency, and a stable structure in which gas molecule B is in the ground state and has no imaginary frequency. The wave functions of gas molecule A in the neutral state, the monovalent cation state, and the monovalent anion state are calculated, as well as the wave functions of gas molecule B in the neutral state, the monovalent cation state, and the monovalent anion state.

3. The method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution according to claim 1, characterized in that: The specific process of step 2 is as follows: Based on the electrostatic potential distribution characteristics of gas molecules A and B, and utilizing the principle of complementary positive and negative potentials, various interaction configurations can be obtained by combining gas molecules A and B. To obtain each interaction configuration The initial structure, utilizing Functional and basis sets for each interaction configuration Geometric optimization and vibration analysis were performed on the initial structure to obtain each interaction configuration. A stable structure in its ground state with no imaginary frequency is calculated, along with the calculation of each interaction configuration. The ratio of the wave function to the Boltzmann distribution of a stable structure in a neutral state.

4. The method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution according to claim 3, characterized in that: The formula for calculating the Boltzmann distribution ratio in step 2 is as follows: （1） in, This is the numbering of the interaction configuration. For the first The proportion of each interaction configuration. For the first A molecule with an interacting configuration, It is a natural constant. For the first The difference in energy between each interaction configuration and the lowest energy configuration. It's temperature. It is the ideal gas constant.

5. The method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution according to claim 1, characterized in that: The specific process of step 3 is as follows: （2） In the formula, Mulliken electronegativity For vertical ionization energy, For vertical electron affinity, For electron energy, This represents the original number of electrons in gas molecule A or gas molecule B. This represents the number of electrons after gas molecule A or gas molecule B ionizes by one electron. The number of electrons after gas molecule A or gas molecule B gains an extra electron.

6. The method for identifying mixed insulating gases based on the positive synergistic effect of atomic charge distribution according to claim 1, characterized in that: The specific process of step 4 is as follows: Based on the wave function of gas molecule A and gas molecule B in the neutral state, and each interaction configuration The wavefunctions were calculated using the Hirshfeld population corrected for atomic dipole moments for gas molecules A, B, and each interaction configuration. The atomic charge distribution, based on gas molecule A, gas molecule B, and each interaction configuration Calculation of atomic charge distribution for each interaction configuration Charge transfer amount, depending on each interaction configuration Boltzmann distribution ratio calculation for each interaction configuration Linear weighted value of charge transfer.

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