Method for obtaining the arrangement of graphene PI heating sheet and heating and keeping warm device

Abstract

A method for obtaining the arrangement of a graphene PI heating sheet and a heating and insulation device, the method including: establishing a parameterized model of a heating and insulation device for a tank body of an SF6 tank-type circuit breaker; calling the established parameterized model and combining it with set input variables to simulate a transient heating process; analyzing the sensitivity of the input variables to the SF6 gas temperature and flow rate, and selecting key input variables from the input variables according to the sensitivity analysis; constructing a test parameter set according to the set experimental design method and the selected key input variables; combining it with the test parameter set and the set response surface construction method to construct a response surface model; performing iterative optimization on the selected key input variables in combination with a set optimization algorithm through the constructed response surface model, obtaining the optimized input variables, and using the optimized input variables to perform the arrangement of the graphene PI heating sheet.

Description

[Technical field]

[0001] This application claims priority to a Chinese patent application bearing application number 202211318376.8, filed with the China Patent Office on October 26, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of high voltage power supply equipment, for example, to a method for acquiring the arrangement of a graphene polyimide (PI) heating sheet and a heating and heat-retaining device. [Background technology]

[0003] Sulfur hexafluoride (SF6) tank-type circuit breakers have been widely applied in ultra-high-voltage, large-capacity power systems, and have the advantages of excellent arc-extinguishing performance, reliable operation, and long-term maintenance-free operation. The gas chamber of an SF6 tank-type circuit breaker is exposed to the atmosphere, and in many SF6 tank-type circuit breakers currently in operation in the power grid, when the environmental temperature is lower than -27.5°C, the SF6 gas will liquefy, causing a sudden drop in pressure in the gas chamber of the SF6 tank-type circuit breaker, which will cause the circuit breaker to issue an alarm, and even close due to pressure, or trip out of sequence, causing serious impacts on the stable operation of the power grid.

[0004] Current tank body heating and insulation devices for SF6 tank-type circuit breakers usually use conventional nickel-chromium alloy resistance sheets for heating. The structure diagram of the nickel-chromium alloy resistance sheet is shown in Figure 1. The nickel-chromium alloy resistance sheet 1 needs to be covered with silicone rubber film 2 on both sides, which reduces the thermal efficiency; the nickel-chromium alloy resistance sheet 1 may melt down after a certain period of use due to its series connection characteristics, which requires the entire heating sheet to be replaced, shortening its lifespan, causing material waste, and potentially causing safety hazards and economic losses; the cutting of the nickel-chromium alloy needs to be done by chemical etching, which is not environmentally friendly, and the cutting design and layout are both limited by its series connection characteristics, which further causes material waste. Summary of the Invention

[0005] The present application provides a method for obtaining the arrangement of a graphene-PI heating sheet, which can be applied to heating and keeping warm the tank body of an SF6 tank-type circuit breaker after the graphene-PI heating sheet is arranged rationally.

[0006] In a first aspect, an embodiment of the present application provides a method for obtaining a configuration of a graphene PI heating sheet, the method including: establishing a parameterized model of a heating and insulation device for a tank body of an SF6 tank-type circuit breaker; calling the established parameterized model and combining it with set input variables to simulate a transient heating process; analyzing the sensitivity of the input variables to SF6 gas temperature and flow rate, and selecting key input variables from the input variables according to the sensitivity analysis; constructing a test parameter set according to a set experimental design method and the selected key input variables; combining it with the test parameter set and a set response surface construction method to construct a response surface model; and performing iterative optimization on the selected key input variables by combining it with a set optimization algorithm using the constructed response surface model to obtain optimized input variables, and using the optimized input variables to configure the graphene PI heating sheet.

[0007] Preferably, the input variables include the length, width and spacing between adjacent graphene PI heating sheets. Preferably, when performing the sensitivity analysis, the arrangement center point of the graphene PI heating sheet and the pole pole top center point of the SF6 tank type circuit breaker are taken as variable reference points, and the SF6 gas temperature and flow velocity at the arrangement center point and the SF6 gas temperature and flow velocity at the pole pole top center point are extracted.

[0008] Preferably, the Spearman rank correlation coefficient method is employed to perform the sensitivity analysis.

[0009] Preferably, after the graphene PI heating sheet is arranged using the optimized input variables, the method further includes simulating the transient heating process in combination with the parameterized model, and verifying the arranged graphene PI heating sheet.

[0010] Preferably, the selected key input variables are iteratively optimized by adopting an optimization method such as screening, multi-objective genetic algorithm (MOGA), non-linear programming by quadratic Lagrangian (NLPQL), or mixed-integer sequential quadratic programming (MISQP).

[0011] In a second aspect, an embodiment of the present application provides a heating and insulation device including a tank body insulation housing, an insulation layer and a heating layer, which are arranged in sequence from outside to inside, wherein the heating layer is formed by connecting a plurality of graphene PI heating sheets in parallel, and the plurality of graphene PI heating sheets are arranged by adopting the graphene PI heating sheet arrangement acquisition method described in the first aspect, and are attached and fixed to the outer surface of the tank body of the SF6 tank-type circuit breaker.

[0012] Preferably, the heat-insulating layer is made of foamed rubber of ethylene propylene diene monomer rubber (EPDM).

[0013] Preferably, the tank body heat-insulating housing is constructed by removably connecting at least two housing parts.

[0014] Preferably, the heating and insulation device further includes a temperature sensor, a temperature controller and a contactor, wherein the temperature sensor is attached to the top end of the pole and connected to the temperature controller, and the contactor is attached to the power supply circuit of the multiple graphene PI heating sheets and connected to the temperature controller. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing the distribution of a nickel-chromium alloy resistance sheet of an SF6 tank-type circuit breaker in the related art. [Diagram 2] FIG. 1 is a flow diagram of the method of Example 1 of the present application. [Diagram 3] FIG. 1 is a schematic diagram of the workflow of the method of Example 1 of the present application. [Figure 4] FIG. 2 is a schematic diagram of extraction of input variables in Example 1 of the present application. [Diagram 5] FIG. 2 is a schematic diagram of grid division according to the first embodiment of the present invention. [Figure 6] FIG. 1 is a schematic diagram showing the construction of a response surface model in Example 1 of the present application. [Figure 7] FIG. 2 is a schematic diagram showing the construction of a response surface model in Example 1 of the present application. [Figure 8] FIG. 1 is a schematic diagram of the heating effect before optimization. [Figure 9] FIG. 2 is a heating effect diagram of the layout plan obtained by adopting the method of Example 1 of the present application. [Figure 10] FIG. 2 is a schematic diagram of the overall structure of Example 2 of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The graphene PI film heating sheet is applied to the heating of the tank body of the SF6 tank-type circuit breaker, which can solve the technical disadvantage of using the nickel-chromium alloy resistance sheet for heating. In this application, the graphene PI film heating sheets, which can be heated in parallel and arbitrarily cut, are rationally arranged and then applied to the heating of the tank body of the SF6 tank-type circuit breaker.

[0017] Example 1 This embodiment provides a method for obtaining a graphene-PI heating sheet arrangement, which includes the following steps, as shown in Figures 2-3.

[0018] In step S1, a parameterized model of a heating and insulation device for the tank body of an SF6 tank-type circuit breaker is established.

[0019] In this embodiment, a parameterized model of the heating and insulation device for the tank body of the SF6 tank-type circuit breaker is established by combining Solidworks and Workbench, and the modeling is carried out by the Design Modeler parameterized modeling module. The modeling method may be any method in the related art, and will not be described here.

[0020] In step S2, a sensitivity analysis of the parameters is performed.

[0021] In this embodiment, as shown in Figure 4, the widths of the graphene PI heating sheets with three specifications are extracted, which are P1, P2, and P3, and the spacing distances between adjacent graphene PI heating sheets are extracted, which are P4, P5, and P6. After the input variables are extracted, they are stored in the parameter manager.

[0022] In this embodiment, a total of six parameters, P1, P2, P3, P4, P5, and P6, are selected as input variables in the parameter manager of the Workbench platform. The values ​​of several sets of input variables are manually set and then stored in the parameter manager. A simulation of the transient heating process is performed according to the set initial experimental design method. The SF6 gas temperature P7 at the center point of the top of the polar column and the SF6 gas temperature P8 at the center point of the arrangement are extracted. The average gas temperature P9 of the middle cross section of SF6 is extracted. The parameter P10 is set as the difference between the SF6 gas temperature at the center point of the arrangement and the SF6 gas temperature at the center point of the top of the polar column. The expression (2) is as follows:

[0023]

number

[0024] The number of samples required to construct the response surface increases significantly with the number of input parameters, resulting in a significant increase in calculation costs. Therefore, the sensitivity of the input variables to the SF6 gas temperature and flow velocity is analyzed, and the input variables are selected according to the sensitivity analysis. In the parameter correlation sensitivity analysis module, the Spearman rank correlation coefficient method is adopted to analyze the sensitivity of the input variables to the SF6 gas temperature and flow velocity, and the input variables are ranked by the degree of correlation to select the input variables.

[0025] In this embodiment, since the parameters P1, P2, and P3 (the widths of heating sheets with three different specifications) are not sensitive to changes in the four output variables P7, P8, P9, and P10, a total of three parameters P4, P5, and P6 are selected as key input variables after screening.

[0026] The method to obtain the gas temperature and flow velocity of SF6 with different input variables through the simulation of the transient heating process is as follows.

[0027] In step a, the Mechanical module is used to perform grid division on the parameterized model constructed in step 1. The model adopts a tetrahedral grid division, and the grid type is set to Computational Fluid Dynamics (CFD) grid. The overall grid size is 30 mm, and a partial grid of 7 mm is adopted for the PI heating sheet for division. The schematic diagram of the grid division is shown in Figure 5.

[0028] In step b, the boundary conditions of the thermal fluid analysis model of the heating and insulation device for the tank body of the SF6 tank-type circuit breaker are set, In this embodiment, the Fluent fluid analysis software in the Workbench platform is used to complete the setting of the boundary conditions of the thermal fluid model by combining with the input variables. The power of the heat source of the PI heating sheet is determined by using the formula (1), and the sheet resistance R c =120Ω.

[0029]

number

[0030] Expand the Enger option for the Energy Equation, select the Realizable k-ε equation for viscosity, and employ the Body Force Weighted pressure equation in the Solution Method panel to ensure natural convection conditions for SF6.

[0031] In step c, a thermal fluid analysis solver for the heating and insulation device for the tank body of the SF6 tank-type circuit breaker is set, The transient thermal fluid solution method is selected, the average gas temperature inside the tank body, the SF6 gas temperature at the center of the arrangement, and the SF6 gas temperature at the center of the pole top end are monitored, the solution time is set to 1800 s, the model is solved, and the SF6 gas flow velocity and temperature distribution inside the tank body of the circuit breaker with different input variables are obtained.

[0032] In step S3, the experimental group is designed and a test parameter set for constructing a response model is completed.

[0033] Central Composite Design or Optimal Space-Filling Design or Box-Behnken Design or Sparse Grid Initialization or Latin Hypercube Sampling Design is selected as the set experimental design method to complete the design of the experimental groups.

[0034] In this embodiment, the experimental design is performed using the design exploration module of the Workbench platform. Since the geometric parameters of the PI heating sheet are continuous variables, the Central Composite Design design method is selected and used as the test design method after optimization. The parameter change range of the input parameters is selected to be 30%. According to the size of the tank body, the test parameters corresponding to 45 sets of selected input variables are manually set and stored in the parameter manager.

[0035] In step S4, a response surface model (RSM) is constructed by combining the test parameters corresponding to the 45 sets of input variables selected in step S3 with a response surface algorithm; The construction of the response surface model can be completed by selecting the construction method of the response surface of Genetic Aggregation, Standard Response Surface, Kriging, Non-Parametric Regression, Neural Network, or Parse Grid, and the construction method can be adopted from the methods in the related art, and the steps thereof will not be described here.

[0036] In this embodiment, according to the test parameter set constructed in step S3, the construction method of the Kriging response surface is selected to complete the construction of the response surface model. Kriging is a multi-dimensional interpolation technique suitable for the optimization problems of highly nonlinear complex processes. The function expression is as shown in Equation (3):

[0037]

number

[0038] In step S5, using the response surface model constructed in step S4, in combination with the input variables selected in step S3, an optimization algorithm such as Screening, MOGA, NLPQL, or MISQP is selected to perform an optimal iterative solution of the input variables, obtain the optimized input variable parameters, and finally obtain the optimal graphene PI heating sheet configuration plan.

[0039] In the embodiment, the response surface model constructed in step S4 is used in combination with the input variables selected in step S3 to select the optimization algorithm of MOGA, and the optimal iterative solution of the input variables is performed to obtain the optimized input variable parameters, and the three optimized graphene PI heating sheet layout plans are finally obtained, as shown in Table 1. The expression for optimizing the objective of the multi-objective optimization in this step is shown in Equation (4), and the constructed objective function requires that the difference P10 between the gas temperature at the layout center point and the gas temperature at the center point of the top of the polar column is less than 35K, and the SF6 gas temperature P7 at the center point of the top of the polar column is greater than 258K, and the maximum value of the average gas temperature P9 of the middle section of SF6 is less than 273K.

[0040]

number

[0041] [Table 1]

[0042] In step S6, after obtaining the optimal graphene PI heating sheet layout plan, the established parameterization model is called again according to the obtained optimal layout plan, and then a simulation analysis of the transient heating process is carried out to verify the effect of the layout plan, of which the effect of the plan before optimization is as shown in Figure 8, and the effect of adopting the method of this embodiment is as shown in Figure 9. In the plan before optimization, the tank body is wrapped with two graphene PI heating sheets to cover the entire outer surface of the tank body.

[0043] As shown in Figures 8 and 9, when the tank body of the SF6 tank-type circuit breaker is heated by adopting the arrangement method of the pre-optimization proposal, the temperature distribution of the tank body is non-uniform and the heat retention performance of the tank body is poor. However, when the tank body of the SF6 tank-type circuit breaker is heated by adopting the arrangement method of the graphene PI heating sheet of this embodiment, the generated heating effect is better, the maximum temperature difference is reduced from 39K to 15K, the overall temperature distribution of the tank body is more uniform, the overall power consumption is smaller and there is a good heat retention effect.

[0044] By adopting the method of this embodiment, a response surface model is constructed and combined with the selected input variables, and the optimal graphene PI heating sheet placement plan is obtained through the optimization algorithm, thereby achieving a good heating effect while minimizing the amount of material used, improving the utilization rate of energy and materials, and solving the problem of how to place the graphene PI heating sheet in the tank body heating and insulation device of the SF6 tank-type circuit breaker. At the same time, the input variables with high sensitivity are selected as input parameters through sensitivity analysis to construct a response surface model, thereby reducing the amount of calculation and greatly reducing the calculation cost.

[0045] Example 2 As shown in FIG. 10, this embodiment provides a heating and insulation device comprising a heating layer 3, a heat-insulating layer 4 and a tank body insulation housing 5, which are arranged in this order from inside to outside, the heating layer 3 being affixed and fixed to the tank body of the SF6 tank type circuit breaker, the heat-insulating layer 4 covering the tank body of the SF6 tank type circuit breaker to which the heating layer 3 is affixed, and the tank body insulation housing 5 being fitted onto the outer periphery of the tank body of the SF6 tank type circuit breaker.

[0046] The heating layer 3 is composed of a plurality of graphene PI heating sheets 13, and the copper electrode 12 is connected to the graphene PI heating sheets 13 by pressing. The connection method between the graphene PI heating sheets 13 and the copper electrodes 12 can be that in the related art. The arrangement plan of the plurality of graphene PI heating sheets 13 is obtained by the method of Example 1, and the plurality of graphene PI heating sheets 13 are arranged to be connected in parallel in a circuit. The power cable passes through the tank body insulation housing 5 and then connects to a power source through a contactor 10 provided in the heating and insulation device.

[0047] The heat-insulating layer 4 is made of EPDM foam rubber.

[0048] The tank body insulation housing 5 is constructed by removably connecting at least two housing parts 51, and in this embodiment, the tank body insulation housing 5 is constructed by fixing at least two housing parts 51 with bolts.

[0049] By adopting this type of structure, structural limitations such as the small spacing between switchgear in Gas Insulated Substations (GIS) and insufficient installation space can be cleverly resolved.

[0050] The heating and keeping device further includes a temperature sensor 11, a temperature controller 9 and a contactor 10. The temperature sensor 11 is mounted on the top end of the pole 6 of the SF6 tank-type circuit breaker, and the temperature sensor 11 is connected to the temperature controller 9, and the temperature controller 9 is connected to a control system mounted inside the control box 8.

[0051] The temperature sensor 11 can collect temperature information and transmit it to the temperature controller 9, and the temperature controller 9 is connected to the contactor 10, and the contactor 10 can control the turning on and off of the graphene PI heating sheet according to the collected temperature information.

[0052] The control of the temperature controller 9 realizes automatic on-site cutoff and power-off, and also realizes centralized control of the management of the elements, which makes it convenient for users to monitor and operate.

[0053] The contactor 10 is activated to automatically cut off and turn off the power supply to the heating layer 3 of the tank body, and the main function of activating the contactor 10 is to activate the heater and send a signal to command the heater to operate. This device can realize centralized monitoring of the heat retention of the tank body.

[0054] The heating and insulation device of this embodiment is used in an SF6 tank-type circuit breaker, and a plurality of graphene PI heating sheets 13 are attached and fixed to the outer surface of the tank body of the SF6 tank-type circuit breaker, the tank body insulation housing 5 is fitted into the tank body of the SF6 tank-type circuit breaker, the tank body of the SF6 tank-type circuit breaker is fixed by a stand 7, the temperature sensor 11 is attached to the top end of the pole 6 of the SF6 tank-type circuit breaker, a current transformer and a gas-filled bushing are attached to the SF6 tank-type circuit breaker, the terminal box of the heating and insulation device is connected to the control box 8 of the SF6 tank-type circuit breaker, and the control system in the control box 8 is configured to control the heating temperature of the heating layer 3. The associated electric control elements of the insulation heating device and the control box are secondary connected through an electric cable.

[0055] The heating and insulation device of this embodiment uses graphene PI heating sheet for heating and is arranged according to the best layout plan, so that it has better thermal conduction efficiency and stability, is more energy-saving and environmentally friendly, makes the operation of the switching equipment more reliable, effectively reduces potential safety hazards for the equipment, and at the same time increases the economic efficiency of the equipment operation. [Explanation of symbols]

[0056] Reference Signs List 1 Nickel-chromium alloy resistance sheet, 2 Silicone rubber film, 3 Heating layer, 4 Thermal insulation layer, 5 Tank body thermal insulation housing, 51 Housing part, 6 Electrode, 7 Stand, 8 Control box, 9 Temperature controller, 10 Contactor, 11 Temperature sensor, 12 Copper electrode, 13 Graphene PI heating sheet.

Claims

1. Sulfur hexafluoride SF ６ Establishing a parameterized model of a heating and insulation device for a tank body of a tank-type circuit breaker; calling the established parameterized model and combining it with input variables to perform a simulation of a transient heating process; SF of the input variables ６ analyzing the sensitivity of the input variables to the gas temperature and flow velocity, and selecting key input variables from the input variables in accordance with the sensitivity analysis; constructing a test parameter set according to the established experimental design method and the selected key input variables; constructing a response surface model in combination with the test parameter set and the established response surface construction method; The response surface model is constructed, and the selected key input variables are iteratively optimized in combination with a set optimization algorithm to obtain optimized input variables, and the graphene PI heating sheet is arranged using the optimized input variables. Method for obtaining the arrangement of graphene polyimide PI heating sheet.

2. The input variables include the length, width and spacing between adjacent graphene PI heating sheets; The method of claim 1.

3. When the sensitivity analysis is performed, the center point of the graphene PI heating sheet and SF ６ The center point of the pole top of the tank-type circuit breaker is set as the variable reference point, and the SF of the arrangement center point ６ The gas temperature and flow rate of the SF at the center of the top end of the pole ６ and extracting the gas temperature and flow velocity of the The method of claim 1.

4. The Spearman rank correlation coefficient method is used to analyze the sensitivity. The method of claim 1.

5. After the graphene PI heating sheet is placed using the optimized input variables, The method further includes simulating the transient heating process in conjunction with the parameterized model and verifying the graphene PI heating sheet after placement. The method of claim 1.

6. 2. Iteratively optimize the selected key input variables by using an optimization method such as screening, multi-objective genetic algorithm (MOGA), Lagrangian nonlinear quadratic programming (NLPQL), or mixed integer sequential quadratic programming (MISQP); The method of claim 1.

7. Science fiction ６ The tank body of the tank-type circuit breaker is provided with a heating layer, a heat retention layer and a tank body heat retention housing, which are sequentially provided from inside to outside, and the heating layer is formed by connecting a plurality of graphene polyimide PI heating sheets in parallel, and the plurality of graphene PI heating sheets are arranged by adopting the graphene PI heating sheet arrangement acquisition method according to any one of claims 1 to 6, and the SF ６ It is attached and fixed to the outer surface of the tank body of the tank-type circuit breaker. Heating and insulation device.

8. The heat-retaining layer is made of ethylene propylene diene monomer rubber (EPDM) foam rubber.

8. The apparatus of claim 7.

9. The tank body heat-insulating housing is configured by removably connecting at least two housing parts.

8. The apparatus of claim 7.

10. Further comprising a temperature sensor, a temperature controller and a contactor, the temperature sensor is attached to the top end of the pole and connected to the temperature controller, and the contactor is attached to the power supply circuit of the plurality of graphene PI heating sheets and connected to the temperature controller.

8. The apparatus of claim 7.

Images