A graphene PI heating sheet arrangement acquisition method and heating and heat preservation device

Abstract

The present invention relates to a method for obtaining the arrangement of graphene PI heating sheets and a heating and heat preservation device, comprising the following steps: establishing a parametric model of the heating and heat preservation device for the SF6 circuit breaker tank body; calling the established parametric model and combining with the set input variables to conduct a transient heating process simulation, and entering the sensitivity analysis of the input variables to the gas temperature and flow velocity of SF6, and screening the input variables according to the sensitivity analysis; constructing a response surface model according to the set experimental design method and the screened input variables in combination with the set response surface construction method; performing iterative optimization on the screened input variables through the constructed response surface model in combination with the set optimization algorithm to obtain the optimal arrangement scheme of the graphene PI heating sheets. By using the method of the present invention, the best distribution scheme of the graphene PI heating sheets in the heat preservation application of the circuit breaker can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage power supply equipment, and in particular to a graphene PI heating sheet arrangement acquisition method and a heating and heat preservation device. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Sulfur hexafluoride circuit breakers have been widely used in ultra-high voltage and large-capacity power systems, with advantages such as excellent arc extinguishing performance, reliable operation and long-term maintenance-free. The gas chamber of the SF6 circuit breaker is exposed to the atmosphere. When the ambient temperature is lower than -15℃, the pressure of the SF6 circuit breaker gas chamber drops sharply; when the ambient temperature is lower than -27.5℃, the SF6 gas will liquefy, causing the circuit breaker to alarm, and even pressure lock, circuit breaker tripping, etc., which seriously affects the stable operation of the power grid.

[0004] The current SF6 circuit breaker tank heating and insulation device usually uses traditional nickel-chromium alloy resistors for heating. The structural diagram of the nickel-chromium alloy resistor is as follows: Figure 1 As shown. The two sides of the nickel-chromium alloy resistor 1 need to be covered with a silicone rubber film 2, which reduces its thermal efficiency; its series characteristics may cause it to be partially melted after a period of use, resulting in the need to replace the entire heating plate, which has a short life and causes waste of materials, and may bring safety hazards and economic losses; the cutting of nickel-chromium alloy needs to be carried out by chemical etching, which is not environmentally friendly, and its cutting design and layout are limited by its series characteristics, which will further cause waste of materials.

[0005] The use of graphene PI film heating sheets can solve the technical defects of using nickel-chromium alloy resistor sheets, but the inventors found that graphene PI film heating sheets have not yet been applied to the heating and thermal insulation of SF6 circuit breaker tanks. In addition, it is a technical problem that needs to be urgently solved in this field to arrange the parallel heating and arbitrarily cut graphene PI film heating sheets in the most reasonable way for application to the heating and thermal insulation of SF6 circuit breaker tanks. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for obtaining the arrangement of graphene PI heating sheets, thereby solving the problem of reasonable arrangement of graphene PI heating sheets on the SF6 circuit breaker tank.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions

[0008] In a first aspect, an embodiment of the present invention provides a method for obtaining a graphene PI heating sheet arrangement, comprising the following steps:

[0009] Build SF 6Parametric model of heating and insulation device for circuit breaker tank;

[0010] Call the established parameterized model and combine it with the set input variables to simulate the transient heating process, and enter the input variable to SF 6 Sensitivity analysis of gas temperature and flow velocity, and screening of input variables based on sensitivity analysis;

[0011] The response surface model is constructed according to the set experimental design method and the screened input variables combined with the set response surface construction method;

[0012] The constructed response surface model is combined with the set optimization algorithm to iteratively optimize the screened input variables to obtain the optimal graphene PI heating sheet arrangement scheme.

[0013] Optionally, the input variables include the length and width of the graphene PI heating sheet and the spacing between adjacent graphene PI heating sheets.

[0014] Optionally, when performing sensitivity analysis, the arrangement center point of the graphene PI heating sheet and the center point of the top of the circuit breaker pole are used as variable reference points to extract the SF of the arrangement center point and the center point of the top of the pole. 6 Gas temperature and flow velocity.

[0015] Optionally, a sensitivity analysis was performed using the spearman rank correlation coefficient threshold.

[0016] Optionally, after obtaining the optimal arrangement of the graphene PI heating sheet, a transient heating process simulation is performed in combination with a parameterized model to verify the optimal arrangement.

[0017] Optionally, Screening or MOGA or NLPQL or MISQP optimization method is used to iteratively optimize the input variables after screening.

[0018] In the second aspect, an embodiment of the present invention provides a heating and heat preservation device, comprising a tank insulation shell, an insulation layer and a heating layer arranged in sequence from the outside to the inside, wherein the heating layer is composed of a plurality of graphene PI heating sheets connected in parallel, and the graphene PI heating sheets are arranged using the arrangement scheme obtained by the graphene PI heating sheet arrangement optimization method described in the first method.

[0019] Optionally, the insulation layer is made of EPDM foam rubber.

[0020] Optionally, the tank insulation shell is composed of at least two shell parts that are detachably connected.

[0021] Optionally, the heating and heat preservation device also includes a temperature sensor for installation on the top of the pole, the temperature sensor is connected to a temperature controller, and the temperature controller is connected to a contactor installed in the power supply circuit of the graphene PI heating plate.

[0022] Beneficial effects of the present invention:

[0023] 1. The arrangement optimization method of the present invention, by constructing a response surface model and combining the screened input variables, obtains the optimal graphene PI heating sheet arrangement scheme through an optimization algorithm, which can achieve a better heating effect while minimizing the use of materials, improves energy and material utilization, and solves the problem of how to arrange the graphene PI heating sheet in the circuit breaker tank insulation heating device.

[0024] 2. The arrangement optimization method of the present invention selects input variables with higher sensitivity as input parameters to construct a response surface model through sensitivity analysis, which reduces the amount of calculation and thus greatly reduces the calculation cost.

[0025] 3. The heating and heat preservation device of the present invention utilizes graphene PI heating sheets for heating and is arranged according to the best arrangement scheme, which has better heat conduction efficiency and stability, is more energy-saving and environmentally friendly, thereby making the operation of the switch equipment more reliable, effectively reducing the potential safety hazards of the equipment, and increasing the economy of the equipment operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings in the specification, which constitute a part of the present application, are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute a limitation on the present application.

[0027] Figure 1 This is a schematic diagram of the distribution of nickel-chromium alloy resistors in existing SF6 circuit breakers;

[0028] Figure 2 This is a flow chart of the method of Example 1 of the present invention;

[0029] Figure 3 This is a schematic diagram of input variable extraction in Example 1 of the present invention;

[0030] Figure 4 This is a schematic diagram of grid division in Example 1 of the present invention;

[0031] Figure 5 Schematic diagram of the response surface model construction in Example 1 of the present invention Figure 1 ;

[0032] Figure 6 Schematic diagram of the response surface model construction in Example 1 of the present invention Figure 2 ;

[0033] Figure 7Schematic diagram of heating effect before optimization;

[0034] Figure 8 This is a heating effect diagram of the arrangement scheme obtained by the method of Example 1 of the present invention;

[0035] Fig. 9 This is a schematic diagram of the overall structure of Embodiment 2 of the present invention;

[0036] Among them, 1. nickel-chromium alloy resistor, 2. silicone rubber membrane, 3. heating layer, 4. insulation layer, 5. tank insulation shell, 6. pole, 7. bracket, 8. control box, 9. temperature controller, 10. contactor, 11. temperature sensor, 12. copper electrode, 13. graphene PI heating sheet. DETAILED DESCRIPTION

[0037] Example 1

[0038] This embodiment provides a method for optimizing the arrangement of graphene PI heating sheets. Figure 2 As shown, the following steps are included:

[0039] Step 1: Create SF 6 Parametric model of heating and insulation device for circuit breaker tank;

[0040] In this embodiment, a parametric model of the heating and insulation device for the SF6 circuit breaker tank is established by coupling Solidwork and Workbench. The modeling is performed by the parametric modeling module of Design Modeler. The modeling method adopts the existing method, which will not be described in detail here.

[0041] Step 2: Perform parameter sensitivity analysis;

[0042] In this embodiment, Figure 3 As shown, the lengths and widths of three types of graphene PI heating sheets are extracted, which are P1, P2, P3, P4, P5, and P6, respectively, and the spacings between adjacent graphene PI heating sheets are extracted, which are P7, P8, and P9, respectively. After the input variables are extracted, they are stored in the parameter manager.

[0043] In this embodiment, a total of 9 parameters, namely P1, P2, P3, P4, P5, P6, P7, P8, and P9, are selected as input variables in the Workbench platform parameter manager. The specific values ​​of multiple groups of input variables are manually set and stored in the parameter manager. The transient heating process is simulated according to the set initial experimental design method to extract the SF of the arrangement center point. 6 Gas temperature P10 and SF at the center of the pole top 6 Gas temperature P11, and extract SF 6The average gas temperature of the middle section is P12, and the setting parameter P13 is the difference between the center gas temperature and the gas temperature at the top of the pole, as expressed in (2).

[0044] P13=P10-P11 (2)

[0045] The number of samples required to construct the response surface will increase significantly with the number of input parameters, which will greatly increase the computational cost. 6 The sensitivity analysis of gas temperature and flow velocity is carried out, and the input variables are screened according to the sensitivity analysis. In the Parameter Correlation sensitivity analysis module, the spearman rank correlation coefficient method is used to input the input variables to SF 6 The sensitivity analysis of gas temperature and flow velocity is carried out, and the input variables are sorted by relevance and screened.

[0046] In this embodiment, parameters P1, P3, and P5 (three different specifications of heating plate lengths) are insensitive to changes in the four output variables P10, P11, P12, and P13. Therefore, a total of six parameters, P2, P4, P6, P7, P8, and P9, are selected as key input variables after screening.

[0047] Specifically, the method for simulating the transient heating process to obtain the SF6 gas temperature and flow velocity under different input variables is as follows:

[0048] Step a: Use the Mechanical module to mesh the parameterized model constructed in step 1. The model is meshed using tetrahedral meshing. Set the mesh type to CFD mesh, the overall mesh size to 30 mm, and use a local mesh of 7 mm for the PI heating plate. The meshing diagram is shown in the figure. Figure 4 .

[0049] Step b: SF 6 Setting boundary conditions for the thermal flow analysis model of the heating and insulation device for the circuit breaker tank;

[0050] In this embodiment, the boundary conditions of the heat flow model are set by combining the input variables with the Fluent fluid analysis software under the Workbench platform. The heat source power of the PI heating plate is determined by formula (1), where the square resistance R C =120Ω.

[0051]

[0052] Open the Energy Equation Enger option, select the viscosity Realizable k-ε equation, and use the Body Force Weighted pressure equation on the calculation method panel to ensure that SF 6 Natural convection state.

[0053] Step c: SF 6 Thermal flow analysis solver settings for the heating and insulation device for the circuit breaker tank;

[0054] Select the transient heat flow solution method to monitor the average temperature of the gas inside the tank and the SF at the center of the arrangement 6 Gas temperature and SF at the center of the pole tip 6 The gas temperature is set to 1800s, and the model is solved to obtain the SF in the circuit breaker tank under different input variables. 6 Gas flow rate and temperature distribution.

[0055] Step 3: Design the experimental group and complete the experimental parameter set for building the response model.

[0056] Select Central Composite Design or Optimal Space-Filling Design or Box-Behnken Design or Sparse Grid Initialization or Latin Hypercube Sampling Design as the set experimental design method and complete the experimental group design.

[0057] In this embodiment, the design exploration module of the Workbench platform is used to perform experimental design. Since the geometric parameters of the PI heating plate are continuous variables, the Central Composite Design design method is selected as the optimized experimental design method. The parameter variation range of the selected input parameters is 30%. According to the size of the tank, 45 groups of experimental parameters corresponding to the screened input variables are manually set and stored in the parameter manager.

[0058] Step 4: Combine the experimental parameters corresponding to the 45 groups of screened input variables obtained in step 3 and the response surface algorithm to construct a response surface model (RSM);

[0059] Specifically, Genetic Aggregation or Standard Response Surface or Kriging or Non-Parametric Regression or Neural Network or parse Grid response surface construction method is selected to complete the construction of the response surface model. The construction method can adopt the existing method, and its specific steps are not described in detail here.

[0060] In this embodiment, according to the experimental parameter set constructed in step 3, the Kriging response surface construction method is selected to complete the construction of the response surface model. Kriging is a multidimensional interpolation technology suitable for highly nonlinear complex engineering optimization problems. The function expression is as follows (3):

[0061]

[0062] In the formula, is the basis function coefficient vector, R -1 is the correlation matrix, r T (x) is the vector of the relationship between the unknown point and the known point, and the resulting response surface is as follows: Figure 5-Figure 6 As shown. Figure 5 The response surface constructed is the relationship between the size of the graphene PI heating sheet and the middle cross section SF 6 The fitted surface of the mean gas temperature, Figure 6 The response surface constructed is the relationship between the size of the graphene PI heating sheet and the center point SF at the top of the pole. 6 The fitting surface of the gas temperature can be constructed using existing methods, and the specific process will not be described in detail here.

[0063] Step 5: Using the response surface model constructed in step 4, combined with the input variables screened in step 3, select an optimization algorithm such as Screening or MOGA or NLPQL or MISQP to perform optimal iterative solution of the input variables, obtain the optimized input variable parameters, and finally obtain the optimal graphene PI heating sheet arrangement scheme.

[0064] In the embodiment, the response surface model constructed in step 4 is used, combined with the input variables screened in step 2, and the MOGA optimization algorithm is selected to perform optimal iterative solution of the input variables to obtain optimized input variable parameters, and finally obtain three groups of optimized graphene PI heating sheet arrangement schemes, as shown in Table 1. The optimization objective expression of the multi-objective optimization in this step is as shown in formula (4), and the constructed objective function requires that the difference P13 between the central gas temperature and the gas temperature at the top of the pole is less than 35K, and the SF at the center point of the top of the pole is less than 10K. 6 The gas temperature P11 is greater than 258K, and SF is sought 6 The average gas temperature P12 in the middle section is the maximum value, but less than 273K.

[0065]

[0066] Table 1

[0067]

[0068] Step 6: After obtaining the optimal graphene PI heating sheet arrangement scheme, according to the obtained optimal arrangement scheme, the established parameterized model is called again to perform transient heating process simulation analysis to verify the effect of the arrangement scheme. The effect of the scheme before optimization is as follows: Figure 7 As shown, the effect of using the method of this embodiment is as follows Figure 8 The optimized solution is that two graphene PI heating sheets wrap the tank body, covering the entire outer surface of the tank body.

[0069] By adopting the method of this embodiment, a response surface model is constructed, and combined with the screened input variables, the optimal graphene PI heating sheet arrangement scheme is obtained through an optimization algorithm, which can achieve a better heating effect while minimizing the use of materials, improve energy and material utilization, and solve the problem of how to arrange the graphene PI heating sheet in the circuit breaker tank insulation heating device. At the same time, through sensitivity analysis, input variables with higher sensitivity are selected as input parameter components of the response surface model, which reduces the amount of calculation, thereby greatly reducing the calculation cost.

[0070] Example 2

[0071] This embodiment provides a heating and heat preservation device, such as Fig. 9 As shown, it includes a tank body insulation shell 5, an insulation layer 4 and a heating layer 3 which are arranged in sequence from the inside to the outside. The tank body insulation shell 5 is used to be sleeved on the outer periphery of the SF6 circuit breaker tank body, and the heating layer 3 is used to be attached and fixed on the tank body of the SF6 circuit breaker.

[0072] The heating layer 3 is composed of a plurality of graphene IP heating sheets 13, and the copper electrode 12 is connected to the heating sheet 13 by pressing. The connection method between the graphene IP heating sheet and the copper electrode 12 can be achieved by the existing technology. The arrangement scheme of the plurality of graphene IP heating sheets 13 is obtained by the method of Example 1, and the plurality of graphene IP heating sheets are arranged in parallel in the circuit, and the power cable thereof passes through the tank insulation shell 5 and is connected to the power supply through a contactor.

[0073] The thermal insulation layer 4 is made of EPDM foam rubber.

[0074] The tank body heat-insulating outer shell 5 is composed of at least two shell parts that are detachably connected. In this embodiment, the tank body heat-insulating outer shell 5 is composed of two shell parts fixed by flanges and bolts.

[0075] This structural form cleverly solves structural limitations such as small spacing between GIS switchgear and insufficient installation space.

[0076] The heating and heat preservation device also includes a temperature sensor 11, which is used to be installed on the top of the SF6 circuit breaker pole 6. The temperature sensor 11 is connected to the temperature controller 9, and the temperature controller 9 is connected to the control system installed inside the control box 8.

[0077] The temperature sensor 11 can collect temperature information and transmit it to the temperature controller 9. The temperature controller 9 is connected to the contactor 10 and can control the start and stop of the graphene IP heating plate through the contactor 10 according to the collected temperature information.

[0078] Under the control of the temperature controller 9, automatic disconnection and shutdown are realized on site, and centralized control is realized in component management, which is convenient for user monitoring and operation.

[0079] The start contactor 10 is used to automatically disconnect and shut down the power supply of the tank heating layer 3; the start contactor 10 is mainly used to start the heater and send a heater operation indication signal. This device can realize centralized monitoring of tank insulation.

[0080] The heating and heat preservation device of this embodiment is used on the SF6 circuit breaker, and the tank heat preservation shell 5 is sleeved on the outer surface of the tank of the circuit breaker; the tank is fixed by the bracket 7, and multiple graphene IP heating sheets 13 are attached and fixed on the outer surface of the tank of the circuit breaker, and the temperature sensor 11 is installed on the top of the pole 6 of the circuit breaker. The circuit breaker is installed with a current transformer and a gas-filled sleeve; the junction box of the heating and heat preservation device is connected to the control box 8 of the circuit breaker, and the control system in the control box 8 is used to control the heating temperature of the heating layer 3. The relevant electric control components of the heat preservation and heating device are connected to the control box through cables.

[0081] The heating and heat preservation device of this embodiment utilizes graphene PI heating sheets for heating and is arranged according to the best arrangement scheme, which has better heat conduction efficiency and stability, is more energy-saving and environmentally friendly, thereby making the switch equipment more reliable, effectively reducing the potential safety hazards of the equipment, and increasing the economy of equipment operation.

[0082] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A method for obtaining the arrangement of graphene PI heating sheets, It is characterized in that The following steps are involved: Build SF 6 Parametric model of heating and insulation device for circuit breaker tank; Call the established parameterized model and combine it with the set input variables to simulate the transient heating process, and enter the input variable to SF 6 Sensitivity analysis of gas temperature and flow velocity, and screening of input variables based on sensitivity analysis; The response surface model is constructed according to the set experimental design method and the screened input variables combined with the set response surface construction method; The constructed response surface model is combined with the set optimization algorithm to iteratively optimize the screened input variables to obtain the optimal graphene PI heating sheet arrangement scheme; The input variables include the length, width, and spacing between adjacent graphene PI heater sheets.

2. A method for obtaining a graphene PI heating sheet arrangement as claimed in claim 1, It is characterized in that When performing sensitivity analysis, the arrangement center point of the graphene PI heating sheet and the center point of the top of the circuit breaker pole are used as variable reference points to extract the SF of the arrangement center point and the center point of the top of the pole. 6 Gas temperature and flow velocity.

3. A method for obtaining a graphene PI heating sheet arrangement as claimed in claim 1, It is characterized in that Sensitivity analysis was performed using the spearman rank correlation coefficient.

4. A method for obtaining a graphene PI heating sheet arrangement as claimed in claim 1, It is characterized in that After obtaining the optimal arrangement of the graphene PI heating sheet, the transient heating process simulation was carried out in combination with the parameterized model to verify the optimal arrangement.

5. A method for obtaining a graphene PI heating sheet arrangement as claimed in claim 1, It is characterized in that Screening or MOGA or NLPQL or MISQP optimization method is used to iteratively optimize the input variables after screening.

6. A heating and heat preservation device, It is characterized in that It comprises a tank insulation shell, an insulation layer and a heating layer which are arranged in sequence from the outside to the inside, wherein the heating layer is composed of a plurality of graphene PI heating sheets connected in parallel, and the graphene PI heating sheets are arranged using the arrangement scheme obtained by the graphene PI heating sheet arrangement acquisition method described in any one of claims 1 to 5.

7. A heating and heat preservation device as claimed in claim 6, It is characterized in that The thermal insulation layer is made of EPDM foam rubber.

8. A heating and heat preservation device as claimed in claim 6, It is characterized in that The tank heat-insulating outer shell is composed of at least two shell parts that are detachably connected.

9. A heating and heat preservation device as claimed in claim 6, It is characterized in that The heating and heat preservation device also includes a temperature sensor for installation at the top of the pole, the temperature sensor is connected to a temperature controller, and the temperature controller is connected to a contactor installed in the power supply circuit of the graphene PI heating plate.

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