Method and device for checking applicability of sulfur hexafluoride substitute gas of double-fracture disconnecting switch

Abstract

The invention provides a double-fracture disconnecting switch sulfur hexafluoride substitute gas applicability verification method, which comprises the following steps: constructing a physical model of equipment according to the structure and operation characteristics of an on-site double-fracture disconnecting switch GIS, and sequentially performing temperature field simulation on SF6 substitute gases C4F7N and N2 mixed according to different proportions; when a simulation result meets a temperature rise condition, continuing to perform electric field simulation check on the model using the insulating gas mixed according to the proportion, and if each part meets the insulation requirement of equipment and the total greenhouse coefficient and the price of the mixed gas are low, determining that the gas mixing proportion at the moment is the optimal proportion of the SF6 mixed substitute gas; the problem that huge greenhouse gas emission is caused to the environment when greenhouse gas is used in traditional high-voltage GIS equipment is solved, and convenience, low-carbon property and economical efficiency of GIS equipment extension application are taken into account. And the damage to equipment and operators caused by over-high temperature rise or inconsistent insulation requirements due to improper use of the insulating gas under a high-voltage condition is effectively avoided.

Description

Technical Field

[0001] The invention belongs to the field of electrical technology. Background Art

[0002] The isolating switch in the gas-insulated switchgear GIS is responsible for isolating the power supply and providing an important function of a safe working environment for the maintenance of the power system. The traditional isolating switch has only one isolating break. Therefore, when the GIS standby interval expansion installation and handover withstand voltage test are carried out, the original operating busbar needs to be shut down to avoid personal injury caused by discharge breakdown of the isolating break during the docking installation construction and the occurrence of equipment safety accidents caused by discharge breakdown. The improved double-break isolating switch can effectively solve the problem that the GIS double busbar needs to be shut down during the long-term expansion and maintenance of the conventional GIS substation. The two breaks of the double-break isolating switch can meet the insulation requirements of the single break respectively. The GIS interval double-break busbar isolating switch technology can not only ensure that the original GIS operating equipment does not need to be shut down during the expansion process and the handover withstand voltage test, but also greatly reduce the risks of GIS docking installation and withstand voltage test after expansion during the expansion process, effectively saving the GIS expansion period, improving construction efficiency, and avoiding power outage losses.

[0003] In the gas-insulated electrical equipment of the power transmission and transformation system, SF6 gas with excellent arc extinguishing and insulation performance has been widely used. According to statistics, the annual SF6 gas consumption in the power industry accounts for about 50% of the global production. Sulfur hexafluoride SF6 gas is also used in the gas chamber of the GIS double-break disconnector that has been put into operation in the first phase or is being improved. However, SF6 is a gas with a very strong greenhouse effect. During the maintenance and commissioning of the equipment, SF6 gas will enter the atmosphere. At the same time, SF6 is extremely difficult to decompose and can survive in the atmosphere for 3,200 years, which has a huge impact on the environment. With the advancement of the "dual carbon" goals, my country will tighten the use of SF6 insulating gas in GIS construction in the future and replace SF6 with environmentally friendly alternative gases. In future GIS non-stop expansion projects, the second phase expansion part needs to use alternative gases. Therefore, for the convenience of substation operation and maintenance, it is necessary to carry out alternative gas suitability verification for the first phase GIS that has been put into operation, especially the double-break disconnectors directly connected to the second phase equipment; at the same time, the newly designed GIS double-break disconnectors also need to be verified for the suitability of alternative gases, and there is currently a lack of better verification methods. Summary of the invention

[0004] The purpose of the present invention is to propose a method for verifying the suitability of sulfur hexafluoride alternative gas for double-break disconnectors. By simulating the temperature field and the electric field, the distribution of the temperature field and the electric field of the double-break disconnector with SF6 alternative gas mixed in different proportions is obtained, and the optimal mixing ratio of the SF6 mixed alternative gas used in the double-break disconnector gas chamber is verified.

[0005] The present invention uses a mixed gas of C4F7N and N2 with better insulation and economic performance as a substitute gas for SF6 in a double-break disconnector, aiming to verify the optimal mixing ratio of the two.

[0006] The inventors have discovered through research that the insulation properties, thermal conduction and thermal convection properties of the above-mentioned alternative gases are different under different component proportions and different pressures. Therefore, for the double-break disconnectors that originally used SF6 as the insulating gas, it is necessary to re-conduct temperature rise verification and internal insulation verification through temperature fluid field and electric field coupling calculation, while taking into account the low carbon nature and economy of the mixed gas. By combining these three aspects, the optimal proportion of alternative gases that meet the temperature rise and insulation requirements can be verified.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for verifying the suitability of sulfur hexafluoride alternative gas for double-break disconnectors, comprising:

[0008] Establish a simulation model of double-break disconnector equipment:

[0009] The simulation model is meshed using a hybrid meshing method, and parameters of the simulation model are set;

[0010] Set the initial mixing ratio of N2 and C4F7N in the alternative gas and the simulation step size;

[0011] According to the parameter settings of the simulation model, the mixing ratio of N2 and C4F7N in the alternative gas is changed in sequence according to the simulation step length, and the temperature field simulation of the equipment is performed to obtain the maximum temperature rise value until the maximum temperature rise value meets the temperature rise condition of the equipment;

[0012] For alternative gases whose maximum temperature rise value meets the temperature rise conditions of the equipment, electric field simulation is performed on the equipment using the alternative gas to determine whether the electric field simulation results meet the electric field strength criterion; if not, the mixing ratio of N2 and C4F7N in the alternative gas is changed in sequence according to the simulation step size and simulated again until the electric field strength criterion is met, and the alternative gas verification passes.

[0013] The establishment of the double-break disconnector equipment simulation model is specifically as follows: according to the requirements of GIS non-stop expansion and field testing or according to the design drawings of the GIS double-break disconnector that has been put into operation in the first phase, a double-break disconnector equipment simulation model that meets the requirements is established, focusing on constructing double-break static contacts, linked moving contacts, special auxiliary grounding devices and matching shells and insulating parts, and appropriately simplifying other parts. The simulation model mainly includes double-break moving and static side contacts, auxiliary grounding devices, insulating parts and shell parts.

[0014] The hybrid meshing method is used to mesh the simulation model, specifically: fine meshing is performed on the three-phase contact part of the double-break disconnector device (when using COMSOL simulation software to mesh this part, select "ultra-fine" mesh size for meshing), and larger cells are used for meshing the shell and the air shell (when using COMSOL simulation software to mesh this part, select "coarser" mesh size for meshing), and a cube with a side length of 2m is established outside the model as a calculation domain in the simulation calculation;

[0015] The three-phase contact part includes the surface fillets of the double-break moving and static contacts, the surface fillets of the auxiliary grounding device moving and static contacts, the junction of the conductor and the insulating part in the electric field calculation, the surface gas area of ​​the conductor and the insulating part in the temperature fluid field calculation, and the contact points of the double-break moving and static contacts.

[0016] The parameter setting of the simulation model is specifically as follows: in the temperature rise simulation, the specific parameters of each part of the model and the density, dynamic viscosity, constant pressure heat capacity and thermal conductivity of different alternative gases are set; the boundary conditions are set for solid and fluid coupled heat transfer; natural convection ventilation conditions are set at the upper and lower tops of the simulation model; in the electric field simulation, the voltage parameters of each contact are set and the grounding boundary conditions are set on the grounding contact.

[0017] The density of the substituted gas is:

[0018] ρ=w1ρ1+w2ρ2

[0019] Among them, w1 and ρ1 are the proportion and density of N2 respectively; w2 and ρ2 are the proportion and density of C4F7N respectively;

[0020] The dynamic viscosity of the alternative gas is:

[0021]

[0022] Wherein, V1 is the dynamic viscosity of N2; V2 is the dynamic viscosity of C4F7N;

[0023] The constant pressure heat capacity of the substituted gas is:

[0024] C p =(Cp,1*m1+Cp,2*m2) / (m1+m2)

[0025] Among them, C p,1 , m1 is the constant pressure heat capacity and mass of N2; C p,2 , m2 is the constant-pressure heat capacity and mass of C4F7N;

[0026] The thermal conductivity of the alternative gas is:

[0027] K mix=x1k1+x2k2

[0028] Among them, k1 and x1 are the thermal conductivity and proportion of N2; k2 and x2 are the thermal conductivity and proportion of C4F7N.

[0029] The initial mixing ratio is that the content of N2 is 100%, and the simulation step is that the content of N2 is reduced by 5%.

[0030] The equipment temperature rise conditions are the factory design requirements for double-break disconnector equipment, specifically: the maximum temperature rise should be less than 60°C.

[0031] The electric field strength criterion is the factory design requirement value of the double-break disconnector equipment, specifically: the electric field modulus value on the surface of the conductor is less than 25kV / mm, and the electric field modulus value on the surface of the insulating component is less than 18kV / mm.

[0032] The present invention also provides a double-break disconnector sulfur hexafluoride alternative gas suitability verification device, comprising:

[0033] Model building module, used to build a simulation model of double-break disconnector equipment:

[0034] A model processing module is used to mesh the simulation model using a hybrid meshing method and set parameters for the simulation model;

[0035] A setting module is used to set the initial mixing ratio of N2 and C4F7N in the alternative gas and the simulation step size;

[0036] Simulation module 1 is used to change the mixing ratio of N2 and C4F7N in the alternative gas in sequence according to the simulation step size according to the parameter setting of the simulation model, and simulate the temperature field of the equipment to obtain the maximum temperature rise value until the maximum temperature rise value meets the temperature rise condition of the equipment;

[0037] Simulation module two is used to perform electric field simulation on the equipment using the alternative gas whose maximum temperature rise value meets the temperature rise conditions of the equipment, and to determine whether the electric field simulation results meet the electric field strength criterion; if not, the mixing ratio of N2 and C4F7N in the alternative gas is changed in sequence according to the simulation step size and simulated again until the electric field strength criterion is met, and the alternative gas verification passes.

[0038] The model building module is specifically used to: establish a simulation model of a double-break disconnector device that meets the requirements according to the requirements of GIS non-stop expansion and field testing or according to the design drawings of the GIS double-break disconnector that has been put into operation in the first phase, focusing on constructing double-break static contacts, linked moving contacts, special auxiliary grounding devices and matching shells and insulating parts, and appropriately simplifying other parts. The simulation model mainly includes double-break moving and static side contacts, auxiliary grounding devices, insulating parts and shell parts.

[0039] The model processing module is specifically used to: perform fine grid division on the three-phase contact part of the double-break disconnector device, and use larger cells to perform grid division on the shell and the air shell.

[0040] The model processing module is also used to: set specific parameters of each part of the model and the density, dynamic viscosity, constant pressure heat capacity and thermal conductivity of different alternative gases in the temperature rise simulation, set the boundary conditions for solid and fluid coupled heat transfer, and set natural convection ventilation conditions at the upper and lower tops of the simulation model; set the voltage parameters of each contact in the electric field simulation and set the grounding boundary conditions on the grounding contact.

[0041] Another aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for verifying the suitability of sulfur hexafluoride alternative gas for a double-break disconnector as described in the first aspect is implemented.

[0042] Another aspect of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for verifying the suitability of sulfur hexafluoride alternative gas for a double-break disconnector as described in the first aspect.

[0043] The present invention selects the mixing ratio of SF6 alternative gas based on economic factors, and performs multi-physical field simulation on the double-break disconnector GIS with insulating mixed gas of different proportions to verify the optimal ratio of SF6 mixed insulating gas. The present invention forms a new GIS equipment design method that can meet the temperature rise and insulation requirements, and can also meet the two future new power infrastructures of non-stop expansion test and low-carbon transformation construction of power grid through multi-physical field simulation design method, taking into account the convenience, low carbon and economy of GIS equipment expansion application; the results can also be used for feasibility evaluation and gas ratio calculation of low-carbon gas substitution for GIS double-break disconnector using pure SF6 during the first phase of construction. Finding the best SF6 mixed alternative gas is conducive to solving the problem of excessive use of greenhouse gases and harming the environment with the widespread application of dual-port disconnectors. In addition, the double-break disconnector equipment works under the high voltage of 110kV, and uses simulation software to simulate the temperature and electric field distribution of different mixed gases filled in the actual equipment, so as to avoid the damage to the equipment and operators caused by improper use of insulating gas under high voltage conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the external housing model of the double-break disconnector in the present invention.

[0045] Figure 2It is a schematic diagram of the internal contact model of the double-break disconnector in the present invention.

[0046] Figure 3 This is a flow chart for verifying the optimal ratio of SF6 replacing mixed gas in a double-break disconnector according to the present invention.

[0047] Figure 4 It is the temperature distribution diagram of a double-break disconnector using a mixed insulating gas C4F7N and N2 with a content ratio of 5:95.

[0048] Figure 5 It is the temperature distribution diagram of a double-break disconnector using a mixed insulating gas C4F7N and N2 with a content ratio of 10:90.

[0049] Figure 6 It is the temperature distribution diagram of a double-break disconnector using a mixed insulating gas C4F7N and N2 with a content ratio of 15:85.

[0050] Figure 7 It is the temperature distribution diagram of a double-break disconnector using a mixed insulating gas C4F7N and N2 with a content ratio of 20:80.

[0051] Figure 8 It is a line graph of the maximum temperature rise of the double-break disconnector and different proportions of mixed gas.

[0052] Fig. 9 This is the electric field distribution diagram of the conductor surface of a double-break disconnector using a mixed insulating gas with a content ratio of C4F7N to N2 of 20:80.

[0053] Fig.10 This is the surface electric field distribution diagram of the insulating parts of a double-break disconnector using a mixed insulating gas with a content ratio of C4F7N to N2 of 20:80. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0055] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0056] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0057] The first aspect of the present invention provides a method for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector GIS, and a simulation model of the double-break disconnector is established in a 1:1 ratio using three-dimensional modeling software. When simplifying the model, sharp corners and gaps (especially wedge-shaped gaps) that have little impact on the simulation results should be optimized as much as possible to effectively reduce the calculation time. Conventional parameters are set for the material properties and boundary conditions of the double-break disconnector model in GIS. A fluid and solid-fluid heat transfer multi-physics field coupling interface is used, wherein the present invention uses the flow of only one fluid, air, in the device and assumes that there is no interaction between the two layers of fluid. The loss generated by electromagnetics is added to the three-phase contacts as a heat source, and the fluid-solid heat multi-physics field coupling method is used to calculate the temperature rise of the double-break disconnector using different mixed insulating gases with N2 content from high to low. When the temperature rise design requirements are met, the electric field simulation is performed on the double-break disconnector model at this time, and the three-phase contact disconnector voltage parameters are set using the electrostatic physical field. The field strength distribution of the internal contacts and external insulating parts is simulated. When all components meet the insulation requirements, the ratio of the mixed insulating gas at this time is the optimal ratio of C4F7N and N2 mixed gas as SF6 substitute gas. When any component does not meet the insulation requirements, the N2 content in the mixed gas is reduced again, and the temperature field and electric field simulations are performed in turn until the requirements are met to obtain the optimal ratio of the mixed gas as SF6 substitute gas.

[0058] This method comprises the following steps:

[0059] S1: A simulation model of a double-outlet disconnector GIS is established based on the actual equipment and simplified appropriately. The simulation model mainly includes the double-break moving and static side contacts, auxiliary grounding devices, insulating parts and shell parts. A larger rectangular block needs to be constructed to simulate the external space of the equipment and to simulate infinite boundaries.

[0060] S2: Complete the material parameter setting, boundary conditions, and mesh division of the double-break disconnector simulation model, and perform temperature rise and electric field simulations respectively. In the temperature rise simulation, the material parameters include the specific parameters of each part of the model and the density, dynamic viscosity, constant pressure heat capacity, and thermal conductivity of different insulating gases; the boundary conditions set solid and fluid coupled heat transfer, and set natural convection ventilation conditions at the top and bottom of the simulation model; in the electric field simulation, set the voltage parameters of each contact and set the grounding boundary conditions on the grounding contact;

[0061] S3: Based on economic factors, the main gas is a gas with a low total greenhouse effect and a relatively low price. The initial ratio of the mixed alternative gas is selected, and the density, dynamic viscosity, constant pressure heat capacity, thermal conductivity, relative dielectric constant and other parameters of the mixed gas are calculated based on the ratio.

[0062] S4: Change the mixing ratio of the mixed gas in sequence according to the set step length, and adjust the corresponding insulation performance, heat conduction and heat convection and other related parameters, perform temperature simulation respectively, record the maximum temperature rise value of the mixed gas with different ratios, and further simulate the electric field of the equipment using the mixed insulating gas with this ratio when the equipment temperature rise condition is met (i.e. the factory design requirement value of the disconnector GIS equipment, specifically: the maximum temperature rise should be less than 60°C). If the field strength of any component does not meet the electric field strength criterion (i.e. the factory design requirement value of the disconnector GIS equipment, specifically: the electric field modulus value of the conductor surface is less than 25kV / mm, and the electric field modulus value of the insulating component surface is less than 18kV / mm), then change the mixed gas ratio calculation again. If all meet the requirements, the most economical mixed gas ratio that meets the temperature and electric field requirements of the double-break disconnector can be used as the optimal ratio of the SF6 environmentally friendly alternative mixed gas.

[0063] The thermal conductivity calculation formula of the alternative mixed gas is:

[0064] K mix =x1k1+x2k2

[0065] Among them, k1 and x1 are the thermal conductivity and proportion of N2; k2 and x2 are the thermal conductivity and proportion of C4F7N.

[0066] The formula for calculating the heat capacity of a mixed gas at constant pressure is:

[0067] C p =(Cp,1*m1+Cp,2*m2) / (m1+m2)

[0068] Among them, C p,1 , m1 is the constant pressure heat capacity and mass of N2; C p,2 , m2 is the constant-pressure heat capacity and mass of C4F7N;

[0069] The formula for calculating the dynamic viscosity of the mixed gas is:

[0070]

[0071] Wherein, V1 is the dynamic viscosity of N2; V2 is the dynamic viscosity of C4F7N;

[0072] The density of the substituted gas is:

[0073] ρ=w1ρ1+w2ρ2

[0074] Among them, w1 and ρ1 are the proportion and density of N2 respectively; w2 and ρ2 are the proportion and density of C4F7N respectively.

[0075] Furthermore, in order to improve the accuracy of the simulation results, it is necessary to finely mesh important parts such as the contacts at both ends of the double-break disconnector. The simulation model of the double-break disconnector has a complex structure. If the uniform meshing method is used, the total number of meshes after division will be huge, making numerical solution difficult to achieve. Therefore, the non-uniform meshing method is used to set a larger mesh size for parts such as the air and the shell to reduce the number of meshes for easy calculation.

[0076] The following is a specific example of this verification method:

[0077] like Figure 1 , a simplified simulation model of the double-break disconnector in GIS is established. The model size of the disconnector is: 1.155m long, 0.656m wide, and 1.033m high. The shell is made of cast aluminum alloy structure with a wall thickness of 14mm. The middle conductive rod is made of copper material T2-Y with a size of 80mm. The contacts on both sides and the middle supporting conductor are made of cast aluminum. Two spring contact finger structures with an inner diameter of 80mm are used on one side. The center insert of the basin insulator is made of aluminum alloy with a diameter of 90mm.

[0078] like Figure 2 The simulation model of the double-break disconnector has a complex structure. The three-phase contact part is divided into fine grids. The equipment housing and air shell are divided into larger cells. The model is divided into 7409269 grids by hybrid grid division. The simulation efficiency is improved by reducing the number of calculation grids while ensuring the accuracy of the simulation results. A cube with a side length of 2m is established outside the model as the calculation domain in the simulation calculation.

[0079] In the process of finite element simulation, the electromagnetic-fluid-temperature three-field coupling is used to calculate the temperature rise. Based on the electromagnetic loss of the switch, the obtained loss is loaded into the physical field simulation model, and the simulation boundary conditions are set as follows: the initial environment and initial fluid temperature are defined as 20°C, the temperature rise rate is 5k / min, the fluid reflux is not considered, the cooling fluid is an incompressible fluid, the fluid normal inflow velocity is 0.01m / s, the initial internal gas pressure is defined as standard atmospheric pressure, and the influence of gravity is considered.

[0080] Relying on the existing double-break disconnector equipment in GIS to conduct SF6 replacement gas verification experiments consumes a lot of financial and material resources, and this equipment works at a high voltage level of 110kV. If the mixed insulating gas of C4F7N and N2 does not meet the requirements of SF6 replacement gas, local excessive temperature rise and high-voltage discharge will cause equipment damage and endanger the life and health of operators. A verification method for SF6 mixed replacement gas in the gas chamber of a double-break disconnector in GIS can reduce the test cost. Using a simplified simulation model, the equipment temperature and field strength distribution diagram of the double-break disconnector in GIS using SF6 to replace the mixed gas of C4F7N and N2 are obtained. The simulation results of using different proportions of mixed insulating gas are compared to verify whether the maximum field strength value and temperature rise requirements allowed by the design are met, and the simulation results are used to verify the optimal proportion of C4F7N and N2 mixed gas as SF6 replacement gas.

[0081] As attached Figure 1 A simulation model was established, starting with a mixed gas ratio of 100% N2, and the temperature field simulation was performed by decreasing the step size of N2 to 5%. The material parameters of the mixed gas in the gas chamber were changed and the maximum temperature rise curve of the double-break disconnector after mixing in different ratios was recorded. When the mixed gas ratio that meets the temperature rise requirements is reached, the electric field simulation of each component of the double-break disconnector using the mixed insulating gas of this ratio is further calculated. When any component does not meet the requirements, the N2 ratio is continuously reduced until the mixed gas ratio that meets the temperature rise and insulation conditions is reached, and the optimal ratio of C4F7N and N2 mixed SF6 alternative gas is determined.

[0082] Figure 4 The double-break disconnector gas chamber is filled with a mixed insulating gas with a content ratio of C4F7N and N2 of 5:95. The temperature distribution diagram under specific working conditions shows that the maximum temperature of the equipment is 99.1℃ when the temperature tends to be stable. The initial temperature of the environment and the double-break disconnector equipment is set to 15℃. The maximum temperature rise of 84.1℃ does not meet the design requirement of less than 60℃.

[0083] Figure 5The double-break disconnector gas chamber is filled with a mixed insulating gas with a content ratio of C4F7N and N2 of 10:90. The temperature distribution diagram under specific working conditions shows that the maximum temperature of the equipment is 87°C when the temperature tends to be stable. The initial temperature of the environment and the double-break disconnector equipment is set to 15°C. The maximum temperature rise of 72°C does not meet the design requirement of less than 60°C.

[0084] Figure 6 The double-break disconnector gas chamber is filled with a mixed insulating gas with a content ratio of C4F7N and N2 of 15:85. The temperature distribution diagram under specific working conditions shows that the maximum temperature of the equipment is 78.8℃ when the temperature tends to be stable. The initial temperature of the environment and the double-break disconnector equipment is set to 15℃. The maximum temperature rise of 63.8℃ does not meet the design requirement of less than 60℃.

[0085] Figure 7 The double-break disconnector gas chamber is filled with a mixed insulating gas with a content ratio of C4F7N and N2 of 20:80. The temperature distribution diagram under specific working conditions shows that the maximum temperature of the equipment is 62.2℃ when the temperature tends to be stable. The initial temperature of the environment and the double-break disconnector equipment is set to 15℃. The maximum temperature rise of 47.2℃ meets the design requirement of less than 60℃. Therefore, the electric field simulation of each component of the double-break disconnector using the mixed insulating gas in this ratio is carried out.

[0086] Fig. 9 The electrostatic distribution diagram of the conductor surface under specific working conditions when the double-break disconnector gas chamber is filled with a mixed insulating gas with a content ratio of C4F7N and N2 of 20:80. From this result, it can be obtained that the maximum electric field modulus on the conductor surface of the double-break disconnector at this time is 16.1kV / mm, which meets the design requirement that the electric field modulus is less than 25kV / mm under the corresponding pressure, so the conductor meets the insulation conditions at this time.

[0087] Fig.10 The electric field distribution diagram of the insulating parts under specific working conditions is obtained by filling the double-break disconnector gas chamber with a mixed insulating gas with a content ratio of C4F7N and N2 of 20:80. From this result, it can be obtained that the maximum electric field modulus value on the surface of the double-break disconnector insulating parts is 15.9kV / mm, which meets the design requirement that the electric field modulus value is less than 18kV / mm under the corresponding pressure, so the insulating parts meet the insulation conditions at this time. Since the temperature rise and electric field modulus of each component of the double-break disconnector meet the equipment design value requirements under the relevant pressure when using the mixed insulating gas with this ratio, and the greenhouse coefficient is relatively high at this time and the expensive gas C4F7N content is the lowest, it is verified that the optimal ratio of SF6 mixed with C4F7N and N2 in the double-break disconnector gas chamber is 2:8.

[0088] The embodiment of the present invention also provides a double-break disconnector sulfur hexafluoride alternative gas suitability verification device, comprising:

[0089] Model building module, used to build a simulation model of double-break disconnector equipment:

[0090] A model processing module is used to mesh the simulation model using a hybrid meshing method and set parameters for the simulation model;

[0091] A setting module is used to set the initial mixing ratio of N2 and C4F7N in the alternative gas and the simulation step size;

[0092] Simulation module 1 is used to change the mixing ratio of N2 and C4F7N in the alternative gas in sequence according to the simulation step size according to the parameter setting of the simulation model, and simulate the temperature field of the equipment to obtain the maximum temperature rise value until the maximum temperature rise value meets the temperature rise condition of the equipment;

[0093] Simulation module two is used to perform electric field simulation on the equipment using the alternative gas whose maximum temperature rise value meets the temperature rise conditions of the equipment, and to determine whether the electric field simulation results meet the electric field strength criterion; if not, the mixing ratio of N2 and C4F7N in the alternative gas is changed in sequence according to the simulation step size and simulated again until the electric field strength criterion is met, and the alternative gas verification passes.

[0094] The model building module is specifically used to: establish a simulation model of a double-break disconnector device that meets the requirements according to the requirements of GIS non-stop expansion and field testing or according to the design drawings of the GIS double-break disconnector that has been put into operation in the first phase, focusing on constructing double-break static contacts, linked moving contacts, special auxiliary grounding devices and matching shells and insulating parts, and appropriately simplifying other parts. The simulation model mainly includes double-break moving and static side contacts, auxiliary grounding devices, insulating parts and shell parts.

[0095] The model processing module is specifically used to: perform fine grid division on the three-phase contact part of the double-break disconnector device, use larger cells to perform grid division on the shell and the air shell, and establish a cube with a side length of 2m outside the model as a calculation domain in the simulation calculation;

[0096] The three-phase contact part includes the surface fillets of the double-break moving and static contacts, the surface fillets of the auxiliary grounding device moving and static contacts, the junction of the conductor and the insulating part in the electric field calculation, the surface gas area of ​​the conductor and the insulating part in the temperature fluid field calculation, and the contact points of the double-break moving and static contacts.

[0097] The model processing module is also used to: set specific parameters of each part of the model and the density, dynamic viscosity, constant pressure heat capacity and thermal conductivity of different alternative gases in the temperature rise simulation, set the boundary conditions for solid and fluid coupled heat transfer, and set natural convection ventilation conditions at the upper and lower tops of the simulation model; set the voltage parameters of each contact in the electric field simulation and set the grounding boundary conditions on the grounding contact.

[0098] Another aspect of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for verifying the suitability of sulfur hexafluoride alternative gas for a double-break disconnector as described in the first aspect is implemented.

[0099] Another aspect of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for verifying the suitability of sulfur hexafluoride substitute gas for a double-break disconnector as described in the first aspect.

[0100] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0101] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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 generate 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.

[0102] 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.

[0103] 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.

[0104] 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 verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector, characterized in that: include: Establish a simulation model of double-break disconnector equipment: The simulation model is meshed using a hybrid meshing method, and parameters of the simulation model are set; Set the initial mixing ratio of N2 and C4F7N in the alternative gas and the simulation step size; According to the parameter settings of the simulation model, the mixing ratio of N2 and C4F7N in the alternative gas is changed in sequence according to the simulation step length, and the temperature field simulation of the equipment is performed to obtain the maximum temperature rise value until the maximum temperature rise value meets the temperature rise condition of the equipment; For alternative gases whose maximum temperature rise value meets the equipment temperature rise condition, electric field simulation is performed on the equipment using the alternative gas to determine whether the electric field simulation result meets the electric field strength criterion; If it is not satisfied, the mixing ratio of N2 and C4F7N in the alternative gas is changed in sequence according to the simulation step size and the simulation is repeated until the electric field strength criterion is met, and the alternative gas verification is passed.

2. The method for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector according to claim 1 is characterized in that: The establishment of the double-break disconnector equipment simulation model is specifically as follows: according to the requirements of GIS non-stop expansion and field testing or according to the design drawings of the GIS double-break disconnector that has been put into operation in the first phase, a double-break disconnector equipment simulation model that meets the requirements is established, focusing on constructing double-break static contacts, linked moving contacts, special auxiliary grounding devices and matching shells and insulating parts, and appropriately simplifying other parts. The simulation model mainly includes double-break moving and static side contacts, auxiliary grounding devices, insulating parts and shell parts.

3. The method for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector according to claim 1 is characterized in that: The hybrid meshing method is used to mesh the simulation model, specifically: fine meshing is performed on the three-phase contact part of the double-break disconnector device, and larger cells are used for meshing the shell and the air shell; the three-phase contact part includes the surface fillets of the double-break moving and static contacts, the surface fillets of the auxiliary grounding device moving and static contacts, the junction of the conductor and the insulating part in the electric field calculation, the surface gas area of ​​the conductor and the insulating part in the temperature fluid field calculation, and the contact points of the double-break moving and static contacts.

4. The method for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector according to claim 1 is characterized in that: The parameters of the simulation model are specifically set as follows: in the temperature rise simulation, specific parameters of each part of the model and the density, dynamic viscosity, constant pressure heat capacity and thermal conductivity of different alternative gases are set; boundary conditions are set for solid and fluid coupled heat transfer; and natural convection ventilation conditions are set at the upper and lower tops of the simulation model; The voltage parameters of each contact are set in the electric field simulation and the grounding boundary conditions are set on the grounding contacts.

5. The method for verifying the suitability of sulfur hexafluoride as a substitute gas for double-break disconnectors according to claim 4, characterized in that: The density of the substituted gas is: ρ=w1ρ1+w2ρ2 Among them, w1 and ρ1 are the proportion and density of N2 respectively; w2 and ρ2 are the proportion and density of C4F7N respectively; The dynamic viscosity of the alternative gas is: Wherein, V1 is the dynamic viscosity of N2; V2 is the dynamic viscosity of C4F7N; The constant pressure heat capacity of the substituted gas is: C p =(Cp,1*m1+Cp,2*m2) / (m1+m2) Among them, C p,1 , m1 is the constant pressure heat capacity and mass of N2; C p,2 , m2 is the constant-pressure heat capacity and mass of C4F7N; The thermal conductivity of the alternative gas is: K mix =x1k1+x2k2 Among them, k1 and x1 are the thermal conductivity and proportion of N2; k2 and x2 are the thermal conductivity and proportion of C4F7N.

6. The method for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector according to claim 1, characterized in that: The initial mixing ratio is that the content of N2 is 100%, and the simulation step is that the content of N2 is reduced by 5%.

7. The method for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector according to claim 1 is characterized in that: The equipment temperature rise conditions are the factory design requirements for double-break disconnector equipment, specifically: the maximum temperature rise should be less than 60°C.

8. The method for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector according to claim 1 is characterized in that: The electric field strength criterion is the factory design requirement value of the double-break disconnector equipment, specifically: the electric field modulus value on the surface of the conductor is less than 25kV / mm, and the electric field modulus value on the surface of the insulating component is less than 18kV / mm.

9. A device for verifying the suitability of sulfur hexafluoride as a substitute gas for a double-break disconnector, characterized in that: include: Model building module, used to build a simulation model of double-break disconnector equipment: A model processing module is used to mesh the simulation model using a hybrid meshing method and set parameters for the simulation model; A setting module is used to set the initial mixing ratio of N2 and C4F7N in the alternative gas and the simulation step size; Simulation module 1 is used to change the mixing ratio of N2 and C4F7N in the alternative gas in sequence according to the simulation step size according to the parameter setting of the simulation model, and simulate the temperature field of the equipment to obtain the maximum temperature rise value until the maximum temperature rise value meets the temperature rise condition of the equipment; Simulation module 2 is used to perform electric field simulation on the equipment using the alternative gas whose maximum temperature rise value meets the equipment temperature rise condition, and determine whether the electric field simulation result meets the electric field strength criterion; If it is not satisfied, the mixing ratio of N2 and C4F7N in the alternative gas is changed in sequence according to the simulation step size and the simulation is repeated until the electric field strength criterion is met, and the alternative gas verification is passed.

10. The double-break disconnector SF6 substitute gas suitability verification device according to claim 9, characterized in that: The model building module is specifically used to: establish a simulation model of a double-break disconnector device that meets the requirements according to the requirements of GIS non-stop expansion and field tests or according to the design drawings of the GIS double-break disconnector that has been put into operation in the first phase, focusing on building double-break static contacts, linked opening and closing moving contacts, special auxiliary grounding devices and matching shells and insulating parts, and appropriately simplifying other parts. The simulation model mainly includes double-break moving and static side contacts, auxiliary grounding devices, insulating parts and shell parts; The model processing module is specifically used to: perform fine grid division on the three-phase contact part of the double-break disconnector device, and use larger cells to perform grid division on the housing and the air casing; The model processing module is also used to: set specific parameters of each part of the model and the density, dynamic viscosity, constant pressure heat capacity and thermal conductivity of different alternative gases in the temperature rise simulation, set the boundary conditions of solid and fluid coupled heat transfer, and set natural convection ventilation conditions at the top and bottom of the simulation model; The voltage parameters of each contact are set in the electric field simulation and the grounding boundary conditions are set on the grounding contacts.

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