Method for designing topology of embedded rtv coating based on tangential hydrophobic migration properties of silicone rubber

Abstract

The application discloses a kind of based on silicon rubber tangential hydrophobic migration characteristics embedded RTV coating topological structure design method, comprising the following steps: determine the quantitative relationship between static contact angle of pollution layer and low molecular weight siloxane concentration;Experimental acquisition hydrophilic / hydrophobic interface patterning surface tangential hydrophobic migration characteristics, with hydrophobic migration distance quantification;Establish the siloxane tangential diffusion mass transfer model and deduce mass transfer function;Fitting RTV manufacturer, interface width and other variable combinations mass transfer parameter;Hydrophobic migration finite element model is constructed;According to connectivity, non-connected, connected, mixed topology is divided and constraint is generated candidate;Simulation screening optimal topology that global hydrophobic time meets the standard;Output parameter is supplied manufacturing verification.This method realizes embedded RTV coating topological structure quantitative design and optimization, fills the existing design blank, can effectively solve coating peeling problem, improves the reliability and economy of long-term operation of insulator.

Description

TECHNICAL FIELD

[0001] The application relates to the technology of external insulation and anti-pollution flashover of power equipment, and in particular to a design method of an embedded RTV coating topological structure based on the tangential hydrophobic migration characteristics of silicone rubber. BACKGROUND

[0002] Insulators for overhead transmission lines mainly include composite insulators and porcelain / glass insulators. The composite insulators have superior anti-pollution flashover performance but relatively general mechanical and durability performance; the porcelain / glass insulators have good mechanical stability and anti-aging performance but insufficient electric anti-pollution performance. In order to take into account the advantages of both, RTV anti-pollution flashover paint is often applied on the surface of the porcelain / glass insulators to improve the anti-pollution flashover performance, and the measure is widely used in power systems.

[0003] However, as an organic insulating material, the RTV has the problems of aging and easy peeling. Field operation data show that the field service life of the conventional coated RTV is usually 6-12 years, which is significantly lower than the designed service life. After the peeling of the coating, the exposure of the hydrophilic substrate can cause a significant decrease in the pollution flashover voltage, increase the operation risk of the line and cause frequent recoating, thereby greatly increasing the operation and maintenance cost.

[0004] In view of the above problems, an embedded RTV coating structure is provided: grooves are formed on the insulator substrate, and the RTV coating is filled into the grooves to form an overall structure composed of the coating part embedded in the substrate and the outer surface layer coating. Compared with the conventional surface coating, the embedded structure can improve the inherent adhesion of the coating and reduce the aging rate of the deep adhesion surface by increasing the bonding area and changing the stress distribution, thereby delaying the overall peeling process.

[0005] In the durability examination of the embedded coating, structural evolution is observed, mainly including: (a) the surface layer coating is complete; (b) the surface layer part is peeled off while the coating embedded in the substrate remains complete; (c) the surface layer is completely peeled off, exposing the interlaced hydrophilic / hydrophobic patterned surface (hereinafter referred to as "patterned surface").

[0006] Considering that the physical process of the silicone rubber surface pollution flashover development usually experiences: hydrophobic migration → wetting → thermal / arc process → complete flashover, whether the hydrophobic migration ability of the patterned surface is retained is directly related to whether the embedded coating can continue to play a pollution flashover prevention role after evolving to the (c) stage. Therefore, when designing the topology of the embedded coating, the hydrophobic migration characteristics of the patterned surface should be considered as an important design consideration. In recent years, research and experiments have found that the silicone rubber has obvious tangential hydrophobic migration phenomenon: in the case of arranging hydrophilic / hydrophobic phases on the surface, due to the concentration gradient of low molecular weight siloxane (LMW, small molecules) in the material, the hydrophobic migration to the hydrophilic area will occur in the tangential direction (in the surface plane), thereby affecting the local surface wettability and hydrophobic migration behavior. The existing topology design of the embedded RTV coating lacks systematic support for the tangential hydrophobic migration characteristics of the silicone rubber, and it is difficult to ensure that the patterned surface can still effectively retain the hydrophobic migration ability to continuously play a pollution flashover prevention role after evolving to the stage of completely shedding the surface layer and exposing the patterned surface.

[0007] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0008] The main purpose of the present application is to overcome the defects existing in the above background art, and to provide a topology design method of embedded RTV coating based on the tangential hydrophobic migration characteristics of silicone rubber, to improve the overall reliability and economy of the embedded RTV coating insulator during long-term service.

[0009] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0010] A topology design method of embedded RTV coating based on the tangential hydrophobic migration characteristics of silicone rubber, comprising the following steps:

[0011] S1. determining the quantitative relationship between the static contact angle of the macroscopic pollution layer and the low molecular weight siloxane concentration in the pollution layer;

[0012] S2. obtaining the tangential hydrophobic migration characteristics of the patterned surface with a hydrophilic / hydrophobic interface through experiments, and taking the hydrophobic migration distance as a quantitative index;

[0013] S3. establishing a mass transfer model of the tangential diffusion of low molecular weight siloxane in the artificial pollution layer, solving the time-varying concentration distribution based on the diffusion equation, initial conditions and boundary conditions, and deriving the mass transfer function;

[0014] S4. Fitting the mass transfer function parameters based on experimental data for different variable combinations, including RTV coating manufacturer, RTV interface width, RTV coating thickness, and contamination layer contamination degree;

[0015] S5. Building a finite element model characterizing the hydrophobic migration process of the hydrophilic / hydrophobic patterned surface, including geometry and mesh partitioning, physical field coupling, boundary and initial condition setting;

[0016] S6. Generating candidate topologies based on pre-set design rules, the topologies are classified into non-connected structures, connected structures, and mixed structures according to connectivity, and multi-dimensional constraints are applied;

[0017] S7. Simulating the hydrophobic migration transient response of the candidate topologies using the finite element model, calculating the global hydrophobic time, and selecting the optimal topology based on performance criteria;

[0018] S8. Outputting the optimal topology structure and its design parameters for subsequent manufacturing and verification.

[0019] Further, in step S1, the quantitative relationship is established based on a surface thermodynamic mixing model, and the contact angle measurement value is converted into the low molecular weight siloxane concentration in the contamination layer through a mathematical relationship between the apparent contact angle of the contamination layer, the apparent contact angle of the RTV coating, the surface roughness factor of the contamination layer, and the low molecular weight siloxane concentration.

[0020] Further, in step S3, the mass transfer model includes a partial differential equation describing the tangential diffusion of low molecular weight siloxane in the contamination layer, which contains a time-varying concentration term, a spatial diffusion term, and a source term; the initial concentration is defined as zero, and the concentration gradient at the boundary is zero; a logarithmic function relationship between total concentration and time is obtained based on experimental data, and the mass transfer function expression is obtained by taking the derivative of the function; further, the concentration-dependent diffusion coefficient is derived from experimental data through concentration distribution analysis method.

[0021] Further, in step S4, the mass transfer function coefficients are fitted for the tangential hydrophobic migration characteristics of RTV coatings from different manufacturers; and under the condition of fixed manufacturer, the power function relationships between the mass transfer function coefficients and the RTV interface width, the RTV coating thickness, and the contamination degree of the contamination layer are established respectively; through the coefficient correction method, the mass transfer function under any variable combination is calculated based on the mass transfer function under known conditions and the variable proportional relationship.

[0022] Further, in step S6, the design rules include: no through high-conductivity band is formed along the creepage distance direction; the minimum size of the topological structure is not less than a predetermined value; the minimum size of the non-topological structure area is not less than a predetermined value; the ratio of the side area of the topological structure to the projected area is greater than a predetermined proportion; the total area covered by the topological structure is less than a predetermined proportion; the edges of the topological structure adopt a round corner transition; the design variables adopt a fixed discrete step length; and the maximum diameter of the non-connected unit in the mixed structure does not exceed a predetermined value.

[0023] Further, in step S6, the non-connected structure, the connected structure and the mixed structure are respectively defined by geometric cell size and spacing parameters, and constraints are imposed based on the design rules, including geometric size lower limit, spacing requirement, area proportion relationship and coverage area upper limit, which are expressed in the form of inequality groups.

[0024] Further, in step S7, the performance criterion is that the global hydrophobic time does not exceed a predetermined threshold value; and the generation process includes: enumerating candidate topologies and identifying on a parameter grid according to the design rules and variable constraints; for each candidate topology, calling a finite element model to calculate the transient response of the hydrophobic migration of the patterned surface according to the corresponding mass transfer function and the pollution layer condition, and recording the global hydrophobic time; and sorting and screening the candidate topologies according to the global hydrophobic time.

[0025] Further, in step S8, the output includes the optimal topologies of the non-connected structure, the connected structure and the mixed structure and their design parameters, including geometric cell width, length, center distance and diameter.

[0026] Further, step S9 is further included: manufacturing a test piece based on the output optimal topological structure, and performing accelerated aging verification and field test.

[0027] A computer program product includes a computer program, which, when executed by a processor, implements the embedded RTV coating topological structure design method based on the tangential hydrophobic migration characteristics of silicone rubber.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The embedded RTV coating structure is an advanced method for solving the RTV coating falling off, and also provides an effective way for the coating falling off problem, but in the prior art, there is lack of scientific design method and systematic design method based on surface characteristics for the topological structure of the embedded coating. Therefore, the embedded RTV coating topological structure design method based on tangential hydrophobic migration characteristics of silicone rubber is provided in the present application, the tangential hydrophobic migration mechanism of the surface is explored, the diffusion model of low molecular weight siloxane in the pollution layer is established, and the topological generation algorithm based on rules is designed, the tangential hydrophobic migration characteristics are explored, the small molecule diffusion model is established, the embedded coating topological structure can be effectively designed, and the quantitative design and optimization of the groove shape of the embedded coating can be realized.

[0030] The present application effectively solves the problems of coating falling off and the degradation of anti-pollution flashover performance caused thereby existing in the long-term service of the existing embedded RTV coating, and makes up for the lack of systematic guidance for the topological design of the existing embedded coating. The design method takes the structural evolution and hydrophobic migration behavior of the hydrophilic / hydrophobic patterned surface that may occur in the service process as the starting point, based on the tangential hydrophobic migration characteristics of the silicone rubber material, through reasonable topological parameter design and implementable processing technology, the coating can still maintain favorable hydrophobic migration / restoration characteristics after the surface layer is aged or partially falls off, thereby delaying the wetting expansion and the occurrence of pollution flashover, reducing the re-coating frequency, and improving the reliability and economy of the long-term operation of the insulator; at the same time, according to the tangential hydrophobic migration characteristics, the topological structure of the patterned surface is designed from the perspective of retaining the hydrophobic migration ability, thereby providing guidance for the design of the embedded RTV coating structure.

[0031] Through the above design method, the present application realizes the following key achievements: 1. the tangential hydrophobic migration characteristics of the hydrophilic / hydrophobic patterned surface are determined; 2. the mathematical model of the tangential diffusion of small molecules and the numerical model of the hydrophobic migration of the hydrophilic / hydrophobic patterned surface are established; 3. a parameterized embedded coating topological design framework is provided, which includes adjustable parameters such as the shape, width, spacing and embedding depth of the groove; 4. an index system for evaluating the hydrophobic migration ability of the patterned surface is established, and an evaluation method based on numerical simulation and experimental verification is formulated, so as to realize quantitative discrimination and optimization selection in the design stage; 5. through the topological optimization guided by the design, the electrical risk and operation and maintenance cost when the coating fails as a whole are reduced, thereby improving the long-term operation safety and economy of the insulator system. The present application also provides a number of simulation and experimental verification examples, which prove the effectiveness of the method in improving the running durability of the embedded coating.

[0032] Other beneficial effects in the embodiments of the present application will be further described below. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Graph of tangential hydrophobic migration distance difference for different RTV coating (formulation difference exists) for different manufacturers.

[0034] Figure 2 Graph of tangential hydrophobic migration distance difference for different RTV interface width.

[0035] Figure 3 Graph of tangential hydrophobic migration distance difference for different RTV coating thickness.

[0036] Figure 4 Graph of tangential hydrophobic migration distance difference for different contamination layer contamination degree.

[0037] Figure 5 Schematic diagram of low molecular weight siloxane tangential model diffusion.

[0038] Figure 6 Flow chart of rule-based topology generation and evaluation.

[0039] Figure 7 Schematic diagram of rule-based topology generation flow and different topology structure contamination layer global hydrophobic time (finite element model simulation result).

[0040] Figure 8 Numerical simulation results of hydrophobic migration transient process of patterned hydrophilic / hydrophobic interlaced surface of representative topology structure.

[0041] Figure 9 Overall flow chart of embedded RTV coating topology structure design method based on silicone rubber tangential hydrophobic migration characteristics. DETAILED DESCRIPTION

[0042] The embodiments of the present application will be described in detail below. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present application and its applications.

[0043] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0044] The present application aims to solve the problems of coating peeling and the degradation of anti-pollution flashover performance caused thereby in long-term service of existing embedded RTV coating, and to make up for the lack of scientific support in the topological design of existing embedded coating, and proposes a topological structure design method for embedded RTV coating based on the tangential hydrophobic migration characteristics of silicone rubber, which realizes quantitative design and optimization of topology by excavating the tangential hydrophobic migration mechanism, establishing a diffusion and mass transfer model of low molecular weight siloxane, and formulating topological generation and screening rules with manufacturing / mechanical / electrical safety constraints, fills the existing design gap and improves the reliability and economy of long-term operation of insulators.

[0045] Referring to Figure 9 The embodiment of the present application provides a topological structure design method for embedded RTV coating based on the tangential hydrophobic migration characteristics of silicone rubber, which comprises the following steps:

[0046] Step S1. Determine the quantitative relationship between the static contact angle of the macroscopic pollution layer and the low molecular weight siloxane concentration in the pollution layer.

[0047] In some embodiments, in step S1, the quantitative relationship is established based on a surface thermodynamic mixing model (such as the Wenzel-Cassie mixing model), and the contact angle measurement value is converted into the low molecular weight siloxane concentration (small molecule concentration) in the pollution layer through a mathematical relationship between the apparent contact angle of the pollution layer, the apparent contact angle of the RTV coating, the surface roughness factor of the pollution layer and the low molecular weight siloxane concentration.

[0048] Step S2. Obtain the tangential hydrophobic migration characteristics of the patterned surface with hydrophilic / hydrophobic interface through experiments, and take the hydrophobic migration distance as the quantitative index.

[0049] Step S3. Establish a mass transfer model of tangential diffusion of low molecular weight siloxane in artificial pollution layer, solve the time-varying concentration distribution based on the diffusion equation, initial condition and boundary condition, and derive the mass transfer function.

[0050] In some embodiments, in step S3, the mass transfer model includes a partial differential equation describing the tangential diffusion of low molecular weight siloxane in the pollution layer, which contains a concentration change over time term, a spatial diffusion term and a source term; the initial concentration is defined as zero, and the concentration gradient at the boundary is zero; the logarithmic function relationship between the total concentration and time is obtained based on experimental data fitting, and the mass transfer function expression is obtained by taking the derivative of the function; further, the concentration-dependent diffusion coefficient is derived from experimental data through concentration distribution analysis method (such as Boltzmann-Matano method).

[0051] Step S4. Fitting the mass transfer function parameters based on experimental data for different variable combinations, including RTV coating manufacturer (corresponding to RTV coating formulations of different manufacturers), RTV interface width, RTV coating thickness, and contamination layer contamination degree.

[0052] In some embodiments, in step S4, the tangential hydrophobic migration characteristics of RTV coatings of different manufacturers are fitted to obtain respective mass transfer function coefficients; and under the condition of a fixed manufacturer, power function relationships of the mass transfer function coefficients with the RTV interface width, the RTV coating thickness, and the contamination layer contamination degree are respectively established; and through a coefficient correction method, the mass transfer function under any variable combination is calculated based on the mass transfer function under known conditions and the variable proportional relationship.

[0053] Step S5. Constructing a finite element model representing the hydrophilic / hydrophobic patterned surface hydrophobic migration process, including geometry and mesh division, physical field coupling, boundary and initial condition setting.

[0054] Step S6. Generating candidate topological structures based on preset design rules, the topological structures being divided into non-connected structures, connected structures, and mixed structures according to connectivity, and multi-dimensional constraints being applied.

[0055] In some embodiments, in step S6, the design rules include: a through high-conductivity band cannot be formed in the direction of the creepage distance; the minimum size of the topological structure is not less than a predetermined value; the minimum size of the non-topological structure area is not less than a predetermined value; the ratio of the side area to the projected area of the topological structure is greater than a predetermined proportion, wherein the connected structure applies a lower lower limit of the ratio; the total area covered by the topological structure is less than a predetermined proportion; the topological edge adopts a round corner transition; the design variable adopts a fixed discrete step length; the maximum diameter of the non-connected unit in the mixed structure does not exceed a predetermined value; and unnecessary entities are avoided on the premise of meeting functional requirements.

[0056] In some embodiments, in step S6, the non-connected structure, the connected structure, and the mixed structure are respectively defined by geometric cell size and spacing parameters, and constraints are applied based on the design rules, including geometric size lower limit, spacing requirement, area proportion relationship, and coverage area upper limit, which are expressed in the form of inequality groups.

[0057] Step S7. Simulating the hydrophobic migration transient response of the candidate topologies using the finite element model, calculating the global hydrophobic time, and selecting the optimal topology based on the performance criteria.

[0058] In some embodiments, in step S7, the performance criterion is that the global hydrophobic time does not exceed a predetermined threshold value; the generating process comprises: enumerating and identifying candidate topologies on a parameter grid according to design rules and variable constraints; for each candidate topology, calling a finite element model to calculate the hydrophobic migration transient response of the patterned surface according to the corresponding mass transfer function and the pollution layer condition, and record the global hydrophobic time; and sorting and screening the candidate topologies according to the global hydrophobic time.

[0059] Step S8. Output the optimal topology structure and its design parameters for subsequent manufacturing and verification.

[0060] In some embodiments, in step S8, the output includes the optimal topologies of non-connected structures, connected structures and mixed structures and their design parameters, including geometric unit width, length, center distance and diameter.

[0061] In some embodiments, the method further comprises step S9: manufacturing a test piece based on the output optimal topology structure, and performing accelerated aging verification and field test.

[0062] The embedded RTV coating topology structure design method based on the tangential hydrophobic migration characteristics of silicone rubber provided by the present application has the following main technical advantages: taking the tangential hydrophobic migration driven by low molecular weight siloxane in silicone rubber as the core physical mechanism of the embedded RTV coating topology design, realizing the guidance of the macroscopic topology layout from the microcosmic diffusion mechanism of the material, and filling the gap of the lack of support for the existing embedded coating topology design; by establishing the tangential diffusion mass transfer model, mass transfer function and concentration-dependent diffusion coefficient of small molecules in the artificial pollution layer, the hydrophobic migration process is quantitatively described, and parameterized input is provided for topology performance prediction; a topology automatic generation and constraint screening method classified according to connectivity (non-connected, connected, mixed) is proposed, and multi-dimensional constraints of manufacturing, mechanics and electrical safety are introduced, taking into account manufacturability and functionality; at the same time, the problems of shedding and degradation of anti-pollution flashover performance of the existing embedded RTV coating in long-term service are effectively solved, the frequency of re-coating and operation and maintenance cost are reduced, and the reliability and economy of the long-term operation of the insulator are improved.

[0063] The specific embodiments of the present application, algorithm examples and verification thereof are further described below.

[0064] An embedded coating topology structure design method based on the tangential hydrophobic migration characteristics of silicone rubber, which realizes quantitative design and optimization of the groove shape of the embedded coating by excavating the tangential hydrophobic migration mechanism, establishing a diffusion model of low molecular weight siloxane in the pollution layer, and designing a rule-based topology generation algorithm.

[0065] Specifically, the embedded coating topology structure design method mainly includes the following processes:

[0066] Step 1: Determine the relationship between the static contact angle of macroscopic contamination layer and the concentration of low molecular weight siloxane in the contamination layer.

[0067] In artificial contamination experiments, kaolin, diatomite and other non-metallic particles are often used as artificial contamination. The artificial contamination layer formed by the accumulation of such non-metallic particles is a typical roughness-dominated heterogeneous surface, which is more suitable for describing its surface thermodynamic behavior using the Wenzel-Cassie mixed model, i.e.:

[0068]

[0069] wherein, θ m is the measured apparent contact angle of the contamination layer, θ RTV is the apparent contact angle of the RTV coating, c is the concentration of low molecular weight siloxane in the contamination layer, γ is the roughness factor of the contamination layer surface, which is the ratio of the total area and the projected area of the rough surface. According to this relationship, the contact angle measurement value is converted into the concentration of small molecules in the contamination layer.

[0070] Step 2: Master the tangential hydrophobic migration characteristics of patterned surfaces with a single hydrophilic / hydrophobic interface.

[0071] In the experiment, the static contact angle of the contamination layer is defined as "hydrophobic" when it is greater than 128°, and "hydrophilic" when it is less than or equal to 128°. The concept of "contamination layer hydrophobic distance" is introduced: the tangential distance from the RTV / base interface to the hydrophilic / hydrophobic transition region of the contamination layer, and this distance is used as a quantitative indicator to characterize the tangential hydrophobic migration ability (tangential hydrophobic migration distance).

[0072] Through systematic experiments, the factors affecting the migration distance are investigated, and the experimental results show that the main influencing variables include: RTV coating manufacturer (there are differences in the formula), RTV interface width (small molecule storage), RTV coating thickness (small molecule storage), and contamination degree of the contamination layer (particle size and accumulation characteristics).

[0073] Step 3: Establish a mass transfer model to describe the tangential diffusion of LMW in the artificial contamination layer, and obtain the time-varying concentration and mass transfer function:

[0074]

[0075] wherein, c is the concentration of LMW inside the contamination layer, D is the diffusion coefficient of LMW in the contamination layer, h is the thickness of the contamination layer (for example, the sample with NSDD of 3.5, h about 88 μm). According to the fitting rule of experimental data, the total concentration of LMW in the contamination layerc total With migration time t (Unit: hours) The following relationship exists:

[0076] ;

[0077] then, c total The mass transfer function can be obtained by differentiating it with respect to time. f mt :

[0078]

[0079] in, α These are the mass transfer function coefficients. Physically, f mt This can be viewed as the relationship between the concentration of small molecules transported per unit area of ​​the RTV interface to the overlying contaminant layer and time. Furthermore, the concentration-dependent diffusion coefficient can be derived from the concentration distribution using the Boltzmann–Matano method. D (c):

[0080] .

[0081] Step 4: Based on the experimentally obtained tangential hydrophobic migration characteristics, solve the mass transfer function under a specific combination of variables.

[0082] Based on steps 2-3, for different combinations of experimental variables (manufacturer, RTV / substrate interface width) w RTV coating thickness δ (e.g., fouling level, NSDD), fitting and solving the corresponding mass transfer function. f mt (or its coefficient) α Specifically, this includes:

[0083] (1) Based on the tangential hydrophobic migration characteristics of RTV coatings from different manufacturers, the mass transfer function coefficients of RTV coatings from different manufacturers were obtained by fitting.

[0084] Table 1 Mass transfer function coefficients of RTV coatings from different manufacturers

[0085]

[0086] (2) Under the condition that the manufacturer is fixed as C, based on different RTV interface widths w Experimental migration characteristics were used to fit the relationship between the mass transfer function coefficient and the interface width:

[0087]

[0088] in,w RTV interface width.

[0089] (3) Similarly, under the condition of fixed manufacturer C, according to the difference of hydrophobic migration characteristics of RTV coating with different thickness, the relationship between mass transfer function coefficient and RTV interface thickness is fitted:

[0090]

[0091] Where δ is the thickness of the RTV coating.

[0092] (4) Finally, according to the influence of contamination degree of contaminated layer on hydrophobic migration characteristics, the mass transfer function coefficient under different contamination degrees is obtained:

[0093]

[0094] Where NSDD is the contamination degree of artificial contaminated layer.

[0095] At this point, for the experimental condition variable group, that is, (manufacturer number, RTV interface width, coating thickness, contamination degree of contaminated layer), the mass transfer function width coefficient correction method can be corrected according to the obtained mass transfer function width coefficient. For example, the mass transfer function under the condition of (C, 5, 0.5, 3.5) is:

[0096] .

[0097] If you need to obtain the mass transfer function of (C, 3, 1.0, 1.0) sample, then:

[0098] .

[0099] Step 5, based on the physical / mathematical model established in step 2, a finite element model is constructed to characterize the hydrophobic migration process of hydrophilic / hydrophobic patterned surface.

[0100] The model points include but are not limited to: geometry and mesh, physical field coupling, boundary and initial conditions and visualization.

[0101] Step 6, develop a rule-based topology generation process.

[0102] First, according to the connectivity, the embedded coating topology is divided into three categories: non-connected structure (single body / island type), connected structure (net / continuous groove type) and mixed structure (combination of connected and non-connected). Based on multiple constraints such as manufacturing, mechanics and electrical safety, the following design rules (Rule 1) are developed to limit the topology parameter space and ensure manufacturability and reliability:

[0103] (1) Do not form a through high-conductivity band along the creepage distance direction (avoid wet area spread).

[0104] (2) The minimum size of the topological structure is not less than 3 mm, and the minimum size of the non-topological structure area is not less than 3 mm (considering the flow and coating filling of ceramic insulator glaze).

[0105] (3) The ratio of the side area of the topological structure to the projected area is greater than 20% (to improve the adhesive force); for the connected structure, the lower limit of the ratio can be relaxed to > 15%.

[0106] (4) The total area covered by the topological structure is ≤ 50% (considering the strength and mechanical integrity of the insulator substrate).

[0107] (5) The topological edge cannot have sharp corners and must use a rounded corner transition (adapt to the stress concentration resistance characteristics of the ceramic glass substrate).

[0108] (6) The design variable discrete step is 2 mm (to facilitate manufacturing and parameterized analysis).

[0109] (7) The maximum diameter D of the non-connected unit in the mixed structure is ≤ 7 mm.

[0110] (7) On the premise of meeting the functional requirements, avoid unnecessary entity increase (simplify manufacturing).

[0111] Based on the above rules, the design variables and constraints of three types of structures are defined respectively:

[0112] (DC) Non-connected structure, variables include: geometric cell center distance d , geometric cell length l , geometric cell width w . The variable constraints given based on the design rules are:

[0113] .

[0114] (C) Connected structure, variables include: geometric cell center distance d , geometric cell length w . The variable constraints given based on the design rules are:

[0115] .

[0116] (H) Mixed structure, variables include: geometric cell center distance d , geometric cell length w , non-connected geometric cell diameter D . The variable constraints given based on the design rules are:

[0117] .

[0118] Step 7: Generate candidate topologies and screen them according to performance criteria (rule 2).

[0119] Rule 2 (hydrophobic migration requirement): In the case of patterned surface, the time required for the whole area to reach a hydrophobic state (whole-area hydrophobic time) shall not exceed 8 hours (i.e. within 8 hours, the patterned surface shall be able to complete effective hydrophobic migration / restoration to suppress wetting expansion).

[0120] The generation process is as follows:

[0121] (1) According to Rule 1 and variable constraints, enumerate candidate topologies on a specified parameter grid (step size 2 mm) and identify them according to the numbering criteria DC / C / H (for example, DC( w , l , d ), C( d , w ), H( d , w , D )).

[0122] (2) For each candidate topology, call the finite element model of Step 5, input the corresponding f mt (sought in Step 4) and the contamination layer conditions, calculate the transient response of the patterned surface to hydrophobic migration and record the whole-area hydrophobic time and other key indicators.

[0123] (3) Sort and select the candidate topologies according to the whole-area hydrophobic time.

[0124] Step 8: Optimal topology and performance summary. For the three types of topologies (non-connected, connected, and mixed), the top three topologies with better performance after examination are given, as well as the corresponding design parameters and predicted whole-area hydrophobic time. This output will be used as a recommended example for subsequent specimen manufacturing, accelerated aging verification, and field testing.

[0125] Table 2 Topology structure design results

[0126]

[0127] The key influencing factors are explored through a series of experiments, and a numerical model is established for simulation analysis. The effectiveness of the above-mentioned embedded RTV coating topology structure design method based on the tangential hydrophobic migration characteristics of silicone rubber is verified, and the experimental data and simulation results are presented in the accompanying drawings. Figure 1 The tangential hydrophobic migration distance difference curves of RTV coatings (corresponding to different formulations) from different manufacturers are shown. Figure 2 The tangential hydrophobic migration distance differences of different RTV interface widths are shown. Figure 3 The tangential hydrophobic migration distance differences of different RTV coating thicknesses are shown. Figure 4 The tangential hydrophobic migration distance differences of different contamination degrees of the contamination layer are shown.​​​Figure 5 A schematic diagram of tangential diffusion of low molecular weight siloxanes is shown. Figure 6 The rule-based topology generation and assessment process was demonstrated. Figure 7 The rule-based topology generation process and the global hydrophobicity time of different topological structures are demonstrated (finite element model simulation results). Figure 8 Numerical simulation results of the hydrophobic migration transient process of patterned hydrophilic / hydrophobic interlaced surfaces with representative topologies are presented.

[0128] In summary, this invention proposes a method for designing an embedded RTV coating topology based on the tangential hydrophobic migration properties of silicone rubber. Its key innovative contributions and design points include:

[0129] (1) The tangential hydrophobic migration driven by low molecular weight siloxanes in silicone rubber is taken as the core physical mechanism for the topology design of embedded RTV coatings. By elevating the hydrophobic migration behavior to a design criterion, a closed loop is achieved to guide the macroscopic topology layout from the microscopic diffusion mechanism of materials, filling the gap of the lack of scientific support in the existing design.

[0130] (2) A mathematical model and mass transfer function for characterizing the transport of small molecules in artificial contamination layers were established. f mt Including experimental fitting c total — t Relationship, derivative expression of mass transfer function, and concentration-dependent diffusion coefficient derived from Boltzmann–Matano. D ( c This model can quantitatively describe the hydrophobic migration process over time, providing usable parameterized inputs for topology performance prediction.

[0131] (3) A set of rule-based automatic topology generation and constraint screening methods were proposed. The structure parameters were classified into three categories: non-connected, connected and mixed according to connectivity. Multi-dimensional constraints such as manufacturing, mechanics and electrical safety (minimum size, area ratio, no through high conductor, rounded corner transition, etc.) were introduced to realize an engineering topology design process that emphasizes both manufacturability and functionality.

[0132] In summary, this invention uses the tangential hydrophobic migration driven by low molecular weight siloxanes in silicone rubber as the core mechanism for embedded RTV coating topology design, filling the gap in existing designs that lack scientific support. At the same time, it provides parameterized inputs for topology performance prediction through mathematical models and mass transfer functions that quantitatively describe the hydrophobic migration process. Furthermore, it relies on an automatic topology generation and screening method with multidimensional constraints to achieve a balance between manufacturability and functionality, ultimately effectively solving the problems of coating peeling and anti-pollution flashover performance degradation, and improving the long-term operational reliability and economy of insulators.

[0133] The embodiment of the present application further provides a storage medium for storing a computer program, which is executed to perform at least the method described above.

[0134] The embodiment of the present application further provides a control device, comprising a processor and a storage medium for storing a computer program; wherein the processor is configured to execute the computer program to perform at least the method described above.

[0135] The embodiment of the present application further provides a processor, which executes a computer program to perform at least the method described above.

[0136] The storage medium can be implemented by any type of nonvolatile storage device, or a combination thereof. The nonvolatile storage device can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a ferromagnetic random access memory (FRAM), a flash memory, a magnetic surface memory, an optical disc or a compact disc read-only memory (CD-ROM). The magnetic surface memory can be a disk memory or a tape memory. The storage medium described in the embodiment of the present application is intended to include, but is not limited to, these and any other suitable types of memory.

[0137] In several embodiments provided by the present application, it should be understood that the disclosed system and method can be implemented in other manners. The described device embodiments are merely illustrative, for example, the division of the units is only a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling between the components can be indirect coupling or direct coupling through some interface, device or unit, and can be electrical, mechanical or other forms.

[0138] The units described as separate components above can or can not be physically separate, and the components shown as units can or can not be physical units, that is, can be located in one place or distributed on multiple network units; part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0139] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be realized in the form of hardware or in the form of hardware plus software functional unit.

[0140] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware, and the foregoing program can be stored in a computer readable storage medium, and the program executes the steps including the above-mentioned method embodiments when executed; and the foregoing storage medium includes: mobile storage device, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk and various storage program codes.

[0141] Alternatively, the integrated unit of the present application, if implemented in the form of a software function module and sold or used as an independent product, can also be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for making a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the methods described in the embodiments of the present application. The foregoing storage medium includes: mobile storage device, ROM, RAM, magnetic disk or optical disk and various storage program codes.

[0142] The methods disclosed in the several method embodiments of the present application can be combined arbitrarily without conflict to obtain new method embodiments.

[0143] The features disclosed in the several product embodiments of the present application can be combined arbitrarily without conflict to obtain new product embodiments.

[0144] The features disclosed in the several method or device embodiments of the present application can be combined arbitrarily without conflict to obtain new method embodiments or device embodiments.

[0145] The above is further detailed description of the present application in combination with specific preferred embodiments, and cannot be deemed as limitation of the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of equivalent substitutions or obvious variations can be made, and the performance or use is the same, which should be deemed as falling within the protection scope of the present application.

Claims

1. A method for designing topology of embedded RTV coating based on tangential hydrophobic migration characteristics of silicone rubber, characterized in that, The method comprises the following steps: S1. determining the quantitative relationship between the macroscopic contamination layer static contact angle and the low molecular mass siloxane concentration in the contamination layer; S2. obtaining the tangential hydrophobic migration characteristics of the patterned surface with a hydrophilic / hydrophobic interface through experiments, and taking the hydrophobic migration distance as a quantitative index; S3. establishing a mass transfer model of tangential diffusion of low molecular mass siloxane in an artificial contamination layer, solving the time-varying concentration distribution based on the diffusion equation, initial conditions and boundary conditions, and deriving the mass transfer function; wherein the mass transfer model comprises a partial differential equation describing the tangential diffusion of low molecular mass siloxane in the contamination layer, and the equation contains a concentration change over time term, a spatial diffusion term and a source term; a logarithmic function relationship between the total concentration and time is obtained based on experimental data fitting, and the mass transfer function expression is obtained by derivation of the function; S4. fitting the mass transfer function parameters based on experimental data for different variable combinations, including RTV coating manufacturers, RTV interface width, RTV coating thickness and contamination degree of the contamination layer; S5. constructing a finite element model for characterizing the hydrophobic migration process of the hydrophilic / hydrophobic patterned surface, including geometry and mesh division, physical field coupling, boundary and initial condition setting; S6. generating candidate topological structures based on preset design rules, the topological structures are divided into non-connected structures, connected structures and mixed structures according to connectivity, and multi-dimensional constraints are applied; S7. simulating the hydrophobic migration transient response of the candidate topologies using the finite element model, calculating the global hydrophobic time, and selecting the optimal topology based on the performance criteria; S8. outputting the optimal topological structure and its design parameters for subsequent manufacturing and verification.

2. The method of claim 1, wherein, In step S1, the quantitative relationship is established based on a surface thermodynamic mixing model, and the contact angle measurement value is converted into the low molecular mass siloxane concentration in the contamination layer through a mathematical relationship between the apparent contact angle of the contamination layer, the apparent contact angle of the RTV coating, the surface roughness factor of the contamination layer and the low molecular mass siloxane concentration.

3. The method of claim 1, wherein, In step S3, the initial concentration is defined as zero, and the concentration gradient at the boundary is zero; further, the concentration-dependent diffusion coefficient is derived from the experimental data through a concentration distribution analysis method.

4. The method according to any one of claims 1 to 3, characterized in that, In step S4, the mass transfer function coefficients of different RTV coating manufacturers are fitted based on the tangential hydrophobic migration characteristics of the RTV coating; and under the condition of a fixed manufacturer, power function relationships between the mass transfer function coefficients and the RTV interface width, the RTV coating thickness and the contamination degree of the contamination layer are established respectively; through a coefficient correction method, the mass transfer function under any variable combination is calculated based on the mass transfer function under known conditions and the variable proportion relationship.

5. The method according to any one of claims 1 to 3, wherein In step S6, the design rules include: no through high-conductivity band can be formed along the creepage distance direction; the minimum size of the topological structure is not less than a predetermined value; the minimum size of the non-topological structure area is not less than a predetermined value; the ratio of the side area to the projection area of the topological structure is greater than a predetermined proportion; the total area covered by the topological structure is less than a predetermined proportion; the topological edge adopts a round corner transition; the design variables adopt a fixed discrete step length; the maximum diameter of the non-connected unit in the mixed structure does not exceed a predetermined value.

6. The method according to any one of claims 1 to 3, wherein In step S6, the non-connected structure, connected structure and hybrid structure are respectively defined by geometric cell size and pitch parameters, and constraints are imposed based on design rules, including lower limits of geometric size, pitch requirements, area proportion relationships and upper limits of coverage area, expressed in the form of inequality groups.

7. The method according to any one of claims 1 to 3, wherein In step S7, the performance criterion is that the global hydrophobic time does not exceed a predetermined threshold; the generation process includes: enumerating candidate topologies and identifying them on the parameter grid according to the design rules and variable constraints; for each candidate topology, calling a finite element model to calculate the transient response of the hydrophobic migration of the patterned surface according to the corresponding mass transfer function and the pollution layer condition, and recording the global hydrophobic time; sorting and screening the candidate topologies according to the global hydrophobic time.

8. The method according to any one of claims 1 to 3, wherein In step S8, the output includes the optimal topologies of the non-connected structure, connected structure and hybrid structure and their design parameters, including geometric cell width, length, center distance and diameter.

9. The method according to any one of claims 1 to 3, wherein, Step S9 is also included: manufacturing test pieces based on the output optimal topology structure, and conducting accelerated aging verification and field test.

10. A computer program product comprising a computer program, characterized in that, The computer program, when executed by the processor, implements the embedded RTV coating topology structure design method based on the tangential hydrophobic migration characteristics of silicone rubber according to any one of claims 1 to 8.

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