A method and device for evaluating the insulation performance of natural ester transformer main insulation, a terminal device and a storage medium

Abstract

The application discloses a kind of natural ester transformer main insulation's insulation performance evaluation method, device, terminal equipment and storage medium, it is related to transformer technical field, method includes: obtaining the structure parameter of transformer, constructs two-dimensional axis symmetry model;Obtain electric field distribution by finite element simulation;Path graph model is constructed, and path graph node is determined;Ant colony parameter is initialized;Repeat executing ant colony search process until reaching maximum iteration number, the discharge path of minimum insulation margin is regarded as potential discharge path;In ant colony search process, each ant constructs discharge path according to current pheromone concentration and path graph node;According to electric field distribution, calculate insulation margin;Pheromone concentration is updated;According to the insulation margin of potential discharge path, the insulation performance of transformer is evaluated. By implementing the present application, the problem that the existing evaluation method based on local maximum field strength cannot reflect the true tolerance state of the transformer can be solved, and the accuracy of the insulation performance evaluation is improved.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and in particular to a method, apparatus, terminal equipment, and storage medium for evaluating the insulation performance of the main insulation of a natural ester transformer. Background Technology

[0002] As a key piece of equipment in the power system, the insulation performance of transformers directly affects the reliability of power grid operation. With increasingly stringent environmental protection and fire prevention requirements, natural ester insulating liquids, due to their high flash point and good biodegradability, are considered an important alternative to traditional mineral oils and are being gradually applied in power transformers.

[0003] Most existing methods for evaluating the insulation performance of transformers are based on the local maximum electric field strength. As long as the local maximum electric field strength is controlled to not exceed the breakdown electric field strength of the insulation material, the insulation system can be guaranteed not to fail.

[0004] However, insulation strength is essentially the withstand capability of the entire insulation system, which depends not only on the field strength at the weakest point in a local area, and existing assessment methods cannot reflect the true withstand state under complex insulation structures. Summary of the Invention

[0005] This invention provides a method, apparatus, terminal equipment, and storage medium for evaluating the insulation performance of the main insulation of a natural ester transformer. This method can solve the problem that existing evaluation methods based on local maximum field strength cannot reflect the true withstand state of the transformer, thereby improving the accuracy of insulation performance evaluation.

[0006] An embodiment of the present invention provides a method for evaluating the insulation performance of the main insulation of a natural ester transformer, comprising: Obtain the structural parameters of the natural ester transformer to be tested and construct a two-dimensional axisymmetric model; The electric field distribution in the main insulating oil gap region was obtained by performing finite element simulation on a two-dimensional axisymmetric model. Based on the electric field distribution in the main insulating oil gap region, a path diagram model is constructed; Based on the path graph model, path graph nodes are determined; path graph nodes are used to represent discrete locations that ants can choose from. Initialize ant colony parameters; ant colony parameters include: initial pheromone concentration and maximum number of iterations; The ant colony search process is repeated until the maximum number of iterations is reached. The discharge path with the smallest insulation margin is selected as the potential discharge path in the main insulating oil gap. The ant colony search process includes: for each ant, constructing a discharge path based on the current pheromone concentration and path graph nodes; for each discharge path, determining the insulation margin based on the electric field distribution of the discharge path; updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration; and using the updated pheromone concentration as the current pheromone concentration for the next execution of the ant colony search process. The current pheromone concentration during the first execution of the ant colony search process is the initial pheromone concentration. The insulation performance of the natural ester transformer under test is evaluated based on the insulation margin of the potential discharge path.

[0007] Furthermore, based on the electric field distribution in the main insulating oil gap region, a path diagram model is constructed, including: Discrete sampling is performed within the main insulating oil gap region, and the spatial location and electric field intensity of each sampling point are extracted to construct the main insulating oil gap sampling point set; For each sampling point pair, the Euclidean distance is calculated based on the spatial position of the two sampling points in the sampling point pair, and an edge is established between the two sampling points corresponding to the sampling point pair if the Euclidean distance does not exceed the preset distance; the sampling point pair consists of any two distinct sampling points in the main insulating oil gap sampling point set. Traverse all sampling point pairs in the main insulating oil gap sampling point set and construct an edge set from all edges; A path graph model is generated based on the main insulating oil gap sampling point set and edge set.

[0008] Furthermore, based on the current pheromone concentration and path graph nodes, a discharge path is constructed, including: Place the ant at the initial node; the initial node is the starting point of the pre-defined discharge path in the path graph node; Repeat the path expansion process to obtain the discharge path; The path expansion process includes: From the edge set, obtain all adjacent nodes that are adjacent to the current node; among them, the current node during the first execution of the path expansion process is the initial node; For each adjacent node, the heuristic function value of the edge formed by the current node and the adjacent nodes is obtained based on the electric field strength of the current node. Calculate the transition probability from the current node to the neighboring node based on the current pheromone concentration and heuristic function value on the edge formed by the current node and its neighboring nodes. From all the transition probabilities of adjacent nodes, select the adjacent node with the highest probability value as the next node; Determine if the next node is the endpoint node. If it is, then the initial node, all selected next nodes, and their corresponding edges form the discharge path. If not, the next node is used as the current node for the next path expansion process. The endpoint node is the pre-defined endpoint of the discharge path in the path graph node.

[0009] Furthermore, based on the electric field distribution along the discharge path, the insulation margin of the discharge path is determined, including: Calculate the cumulative average electric field strength of the discharge path based on the electric field distribution along the discharge path. In the path diagram model, sampling points on the winding surface are extracted to form a set of winding nodes; The type of insulating medium interface traversed by the discharge path is determined based on the shortest distance from the sampling point in the discharge path to the set of winding nodes. Obtain the operating conditions of the natural ester transformer to be tested; The allowable average electric field strength of the discharge path is determined based on the operating conditions of the natural ester transformer to be tested and the type of insulating medium interface that the discharge path passes through. The insulation margin of the discharge path is determined by the ratio of the allowable average electric field strength to the cumulative average electric field strength.

[0010] Furthermore, ant colony parameters also include: pheromone evaporation coefficient; Based on the insulation margin of each discharge path, the pheromone concentration is updated to obtain the updated pheromone concentration, including: Based on the pheromone evaporation coefficient, the current pheromone concentration of each discharge path is volatilized to obtain the pheromone concentration after volatilization. Based on the insulation margin of each discharge path, determine the pheromone increment of the edges traversed by each discharge path; The updated pheromone concentration is obtained by summing the pheromone concentration after evaporation with the pheromone increment.

[0011] Furthermore, based on the insulation margin of potential discharge paths, the insulation performance of the natural ester transformer under test is evaluated, including: The insulation margin of potential discharge paths is compared with a preset insulation threshold. If the insulation margin of a potential discharge path is greater than the preset insulation threshold, the insulation performance of the natural ester transformer to be tested is determined to be free of main insulation discharge risk. If the insulation margin of a potential discharge path is less than or equal to a preset insulation threshold, the insulation performance of the natural ester transformer under test is determined to have a risk of main insulation discharge.

[0012] Furthermore, after assessing the insulation performance of the natural ester transformer under test based on the insulation margin of potential discharge paths, the process also includes: Given that the insulation performance of the natural ester transformer under test poses a risk of main insulation discharge, suggestions for optimizing the insulation structure are generated.

[0013] Based on the above method embodiments, the present invention provides corresponding device embodiments, including: a finite element model construction module, a finite element model simulation module, a path graph model construction module, a path graph node determination module, a parameter initialization module, an ant colony search module, and an insulation performance evaluation module; The finite element model building module is used to obtain the structural parameters of the natural ester transformer to be tested and to build a two-dimensional axisymmetric model. The finite element model simulation module is used to perform electric field finite element simulation on a two-dimensional axisymmetric model to obtain the electric field distribution in the main insulating oil gap region. The path graph model building module is used to build a path graph model based on the electric field distribution in the main insulating oil gap region. The path graph node determination module is used to determine path graph nodes based on the path graph model; path graph nodes are used to represent discrete positions that ants can choose from. The parameter initialization module is used to initialize ant colony parameters, including: initial pheromone concentration and maximum number of iterations. The ant colony search module is used to repeatedly execute the ant colony search process until the maximum number of iterations is reached, and the discharge path with the smallest insulation margin is selected as the potential discharge path in the main insulating oil gap. The ant colony search process includes: for each ant, constructing a discharge path based on the current pheromone concentration and path graph nodes; for each discharge path, determining the insulation margin of the discharge path based on the electric field distribution of the discharge path; updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration; and using the updated pheromone concentration as the current pheromone concentration for the next execution of the ant colony search process; wherein, the current pheromone concentration when the ant colony search process is executed for the first time is the initial pheromone concentration. The insulation performance evaluation module is used to evaluate the insulation performance of the natural ester transformer under test based on the insulation margin of potential discharge paths.

[0014] Based on the above method embodiments, the present invention provides a corresponding terminal device embodiment, including: a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the steps of the insulation performance evaluation method for the main insulation of a natural ester transformer as described in the present invention.

[0015] Based on the above method embodiments, the present invention provides a corresponding computer-readable storage medium embodiment, including: a stored computer program, which, when the computer program is running, controls the device where the computer-readable storage medium is located to perform the steps of the insulation performance evaluation method for the main insulation of the natural ester transformer as described in the present invention.

[0016] Compared with the prior art, the beneficial effects of this embodiment are as follows: This invention obtains the structural parameters of the natural ester transformer to be tested and constructs a two-dimensional axisymmetric model. Finite element method (FEM) simulation of the electric field is performed on the two-dimensional axisymmetric model to obtain the electric field distribution in the main insulating oil gap region. Through FEM simulation, the complete electric field distribution within the main insulating oil gap is obtained. Based on the electric field distribution in the main insulating oil gap region, a path graph model is constructed. Based on the path graph model, path graph nodes are determined to represent discrete positions selectable by ants, which can completely represent all possible discharge paths within the oil gap, rather than focusing only on the field strength at a single point. Ant colony parameters are initialized; the ant colony search process is repeatedly executed, including: for each ant, constructing a discharge path based on the current pheromone concentration and path graph nodes; for each discharge path, determining the insulation margin of the discharge path based on the electric field distribution of the discharge path; updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration; and using the updated pheromone concentration as the current pheromone concentration for the next execution of the ant colony search process. When the maximum number of iterations is reached, the discharge path with the smallest insulation margin is selected. This path can accurately reflect the weakest and most likely discharge path of the oil gap under actual voltage. It is used as the potential discharge path in the main insulation oil gap. Finally, the insulation performance of the natural ester transformer under test is evaluated based on the insulation margin of the potential discharge path, so as to objectively reflect the overall withstand state of the transformer's main insulation.

[0017] In summary, this invention obtains the global electric field distribution through finite element simulation and uses the ant colony algorithm to locate the discharge path with the minimum insulation margin, replacing the traditional local maximum field strength as the evaluation basis. This solves the problem that existing evaluation methods based on local maximum field strength cannot reflect the true withstand state of the transformer, and improves the accuracy of insulation performance evaluation. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a method for evaluating the insulation performance of the main insulation of a natural ester transformer according to an embodiment of the present invention. Figure 2 This is an electric field distribution diagram of a typical discharge path in the main insulating oil gap of a transformer provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the insulation performance evaluation device for the main insulation of a natural ester transformer provided in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0021] like Figure 1 As shown, in order to address the problem that existing evaluation methods based on local maximum field strength cannot reflect the true withstand state of transformers, an embodiment of the present invention provides an insulation performance evaluation method for the main insulation of a natural ester transformer, which includes at least the following steps: Step S1: Obtain the structural parameters of the natural ester transformer to be tested and construct a two-dimensional axisymmetric model; For step S1, the structural parameters of the natural ester transformer to be tested are extracted from the structural drawings. In this embodiment, the natural ester transformer to be tested includes windings, an iron core, natural ester insulating fluid, and solid insulating components. The structural parameters of the windings include the inner diameter, outer diameter, axial height, inter-winding distance, number of turns per winding, and conductor size of each coil. The structural parameters of the iron core include the core dimensions. The structural parameters of the natural ester insulating fluid include the oil channel dimensions and distribution location. The structural parameters of the solid insulating components include the insulation paperboard thickness, corner ring dimensions, and location. Simultaneously, the tank dimensions also need to be extracted to provide complete geometric and material basis for subsequent modeling.

[0022] On the finite element simulation platform, a two-dimensional axisymmetric model containing all windings, iron core, natural ester insulating liquid and solid insulation is established based on the above structural parameters. The relative permittivity of the natural ester insulating liquid and solid insulating materials is set to accurately characterize their insulation properties.

[0023] Subsequently, boundary conditions were configured for the two-dimensional axisymmetric model. The axis of symmetry was set as the "axisymmetric" boundary, the iron core and oil tank were set as grounded, and the outer boundary of the model was set as "zero charge" to simulate the electric field constraint under real working conditions.

[0024] Finally, the two-dimensional axisymmetric model is meshed using an adaptive triangular mesh, and a mapped mesh is used at the material interface to ensure mesh continuity at the interface, thereby improving the accuracy and convergence of the electric field simulation calculation.

[0025] Step S2: Perform finite element simulation of the electric field on the two-dimensional axisymmetric model to obtain the electric field distribution in the main insulating oil gap region; For step S2, the excitation voltage corresponding to each block of the winding is applied to the two-dimensional axisymmetric model through the finite element simulation platform, and the electric field finite element simulation calculation is performed to obtain the electric field intensity distribution at each spatial location in the main insulating oil gap region inside the natural ester transformer.

[0026] This invention obtains the complete electric field distribution within the main insulating oil gap through finite element simulation, rather than a single local maximum field strength. This provides global and continuous electric field data support for subsequent path-based insulation margin assessment, making the search for potential discharge paths and the judgment of insulation performance more accurate.

[0027] Step S3: Construct a path diagram model based on the electric field distribution in the main insulating oil gap region; In a preferred embodiment, a path diagram model is constructed based on the electric field distribution in the main insulating oil gap region, including: Discrete sampling is performed within the main insulating oil gap region, and the spatial location and electric field intensity of each sampling point are extracted to construct the main insulating oil gap sampling point set; For each sampling point pair, the Euclidean distance is calculated based on the spatial position of the two sampling points in the sampling point pair, and an edge is established between the two sampling points corresponding to the sampling point pair if the Euclidean distance does not exceed the preset distance; the sampling point pair consists of any two distinct sampling points in the main insulating oil gap sampling point set. Traverse all sampling point pairs in the main insulating oil gap sampling point set and construct an edge set from all edges; A path graph model is generated based on the main insulating oil gap sampling point set and edge set.

[0028] For step S3, discrete sampling is performed within the main insulating oil gap region, selecting... For each selected sampling point, [number] sampling points are used. Extracting sampling points in a two-dimensional axisymmetric model coordinates and the corresponding electric field strength ,in, , and They represent the first The radial and axial coordinates of each sampling point in the two-dimensional axisymmetric model. Indicates the index of the sampling point, and , This represents the total number of sampling points.

[0029] Will The sampling points are integrated to construct the main insulating oil gap sampling point set: ; in, This represents the set of sampling points for the main insulating oil gap.

[0030] Sampling point set for main insulating oil gap For any two distinct pairs of sampling points, the Euclidean distance is calculated using the following formula, based on the spatial location of the sampling point pair: ; in, Indicates the first sampling point in the main insulating oil gap sampling point set. sampling points Spatial position vector in a two-dimensional axisymmetric model Indicates the first sampling point in the main insulating oil gap sampling point set. sampling points Spatial position vector in a two-dimensional axisymmetric model Indicates sampling point and sampling points The Euclidean distance between them.

[0031] It should be noted that, and They are two independent index variables, and satisfy... This ensures that the distance between two different sampling points is being calculated.

[0032] When any two sampling points and Euclidean distance between The following conditions must be met: ; Then at the sampling point and sampling points Establish an edge between them This serves as a continuous segment within the oil gap discharge path. Indicates the preset distance.

[0033] When traversing all sampling point pairs and The sampling points of the main insulating oil gap will be collected sequentially. All index combinations in the array will satisfy the condition for the edge. Summarize them to form an edge set. : ; Based on the main insulating oil gap sampling point set Sum of edges Generate path graph model : ; By constructing a path graph model The continuous main insulating oil gap space inside the natural ester transformer is discretized into a set of main insulating oil gap sampling points. (Node) and Edge Set The topological graph formed by the (connections) transforms the electric field distribution and spatial structure into computable and traversable structured data.

[0034] Step S4: Determine the path graph nodes based on the path graph model; path graph nodes are used to represent discrete locations that ants can choose from. For step S4, based on the path graph model Determine the nodes of the path graph; these nodes constitute the set of sampling points for the main insulating oil gap. Each sampling point in These sampling points, as discretized spatial locations, provide ants in the ant colony algorithm with selectable moving nodes.

[0035] By transforming the continuous main insulating oil gap space into these discrete nodes, ants can navigate in a path graph model. In this process, based on heuristic information such as electric field strength, the system selects and moves between different nodes, thereby gradually constructing and optimizing the discharge path.

[0036] Step S5: Initialize ant colony parameters; ant colony parameters include: initial pheromone concentration and maximum number of iterations; Preferably, the ant colony parameters also include: pheromone volatility coefficient; For step S5, in order to search for the path with the minimum insulation margin among all feasible paths, this invention introduces the Ant Colony Optimization (ACO) algorithm for optimization.

[0037] First, initialize the ant colony parameters, setting the number of ants to be... The initial pheromone concentration was The pheromone volatility coefficient is The pheromone weighting factor is The heuristic function weighting factor is The maximum number of iterations is .

[0038] Define edge The heuristic function is: ; in, Representing an edge The heuristic function value is used to guide the path selection in the ant colony algorithm. The larger the value, the stronger the ant's tendency to choose that edge. Indicates sampling point The electric field strength at that location.

[0039] This invention uses electric field strength as a heuristic function, which means that regions with higher electric field strength are more attractive to ants for path selection, thus making the algorithm more inclined to search for potential discharge paths with higher electric field strength and smaller insulation margin.

[0040] Step S6: Repeat the ant colony search process until the maximum number of iterations is reached, and select the discharge path with the smallest insulation margin as the potential discharge path in the main insulating oil gap. The ant colony search process includes: for each ant, constructing a discharge path based on the current pheromone concentration and path graph nodes; for each discharge path, determining the insulation margin of the discharge path based on the electric field distribution of the discharge path; updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration; and using the updated pheromone concentration as the current pheromone concentration for the next execution of the ant colony search process. The current pheromone concentration during the first execution of the ant colony search process is the initial pheromone concentration. For step S6, the ant colony search process is executed iteratively, with the maximum number of iterations. As a termination condition, the potential discharge path with the smallest insulation margin is found in the path graph model, and finally the weakest path of the main insulation oil gap insulation performance of the natural ester transformer is located.

[0041] In practice, starting from the first iteration, each complete ant colony search process is counted as one iteration, and this process is repeated until the iteration count reaches the preset maximum number of iterations. At this point, the path with the smallest insulation margin value among all the discharge paths searched during the iteration process is determined as the potential discharge path in the main insulating oil gap.

[0042] The specific process of ant colony search is as follows: First, for each ant in the colony, a discharge path is constructed using a path graph model as the spatial carrier and combined with the current pheromone concentration.

[0043] It should be noted that pheromone concentration serves as a signal guiding ants to choose paths, and pheromone concentration is present on each edge of the path graph model. The distribution of the nodes in the graph reflects the relative merits of each path during the historical search process. Ants tend to choose edges with higher pheromone concentrations during path selection. The nodes in the path graph represent the main set of insulating oil gap sampling points. Each sampling point in As the basic spatial unit constituting a potential discharge path, it provides discretized positional support for the movement and path construction of ants. Ants construct complete discharge paths by moving between different nodes.

[0044] Preferably, based on the current pheromone concentration and path graph nodes, a discharge path is constructed, including: Place the ant at the initial node; the initial node is the starting point of the pre-defined discharge path in the path graph node; Repeat the path expansion process to obtain the discharge path; The path expansion process includes: From the edge set, obtain all adjacent nodes that are adjacent to the current node; among them, the current node during the first execution of the path expansion process is the initial node; For each adjacent node, the heuristic function value of the edge formed by the current node and the adjacent nodes is obtained based on the electric field strength of the current node. Calculate the transition probability from the current node to the neighboring node based on the current pheromone concentration and heuristic function value on the edge formed by the current node and its neighboring nodes. From all the transition probabilities of adjacent nodes, select the adjacent node with the highest probability value as the next node; Determine if the next node is the endpoint node. If it is, then the initial node, all selected next nodes, and their corresponding edges form the discharge path. If not, the next node is used as the current node for the next path expansion process. The endpoint node is the pre-defined endpoint of the discharge path in the path graph node.

[0045] Specifically, first, each ant is placed at a pre-set initial node. The initial node is the starting point of the discharge path marked in the path graph node according to the transformer insulation structure and discharge risk characteristics. It usually corresponds to a critical starting position with high electric field strength or insulation structure.

[0046] Subsequently, starting from the initial node, the ant repeats the path expansion process, gradually extending the path by continuously selecting the next node until the termination condition is met, thus obtaining a complete discharge path. The entire process simulates the behavior of ants searching for food in nature, gradually constructing a globally optimal path through local selection.

[0047] The specific execution logic of the path expansion process is as follows: From the set of edges Obtain all adjacent nodes that are adjacent to the current node, thus obtaining the set of adjacent nodes. It should be noted that during the first path expansion, the current node is the initial node, and in subsequent iterations, the node selected in the previous round is used as the current node.

[0048] For each adjacent node, based on the electric field strength of the current node, the heuristic function value of the edge formed by the current node and the adjacent node is calculated through the heuristic function. The heuristic function value reflects the guiding role of the electric field strength on path selection. The higher the electric field strength, the larger the heuristic function value, and the stronger the attraction to ants, thus guiding the algorithm to prioritize searching for areas with weak insulation performance.

[0049] Based on the current pheromone concentration and heuristic function value on the edge formed by the current node and its neighboring nodes, the transition probability from the current node to a neighboring node is calculated using the following formula: ; in, Indicates the first In this iteration, the ant starts from the node Transfer to node The transition probability, Representing an edge The concentration of pheromones on the surface Represents a node any adjacent node, Represents a node The set of adjacent nodes, Representing an edge The concentration of pheromones on the surface Representing an edge heuristic function values, For connecting nodes With adjacent nodes An edge belongs to the edge set. One of the elements.

[0050] From the transition probabilities of all adjacent nodes, select the adjacent node with the highest probability value as the next node, ensuring that the ant moves in the direction of high pheromone concentration and high electric field strength.

[0051] Finally, determine whether the next node is a pre-set endpoint node. If so, combine the initial node, all selected next nodes, and their corresponding edges to form a complete discharge path. If not, use the next node as the current node for the next path expansion process and continue repeating the above path expansion steps until the endpoint node is reached.

[0052] Through the above path expansion process, several discharge paths for the main insulating oil gaps are formed, and the discharge path of any one of the main insulating oil gaps... It can be represented as a sequence consisting of several consecutive sampling points: ; in, The discharge paths are as follows: The sampling points passed through, Indicates the discharge path The total number of sampling points included.

[0053] Path length Defined as the sum of the distances between each sampling point, i.e.: ; in, Indicates the discharge path The Middle The length of the segment path, specifically the length of two adjacent sampling points. and The Euclidean distance between them The calculation formula is as follows: ; in, Indicates sampling point Spatial position vector in a two-dimensional axisymmetric model Indicates sampling point Spatial position vector in a two-dimensional axisymmetric model.

[0054] To visually demonstrate the specific morphology of the aforementioned discharge path within the main insulating oil gap and its relationship with the electric field distribution, through... Figure 2 The diagram shows the electric field distribution along a typical discharge path in the main insulating oil gap of a transformer. Different colors in the diagram represent different electric field intensities (unit: ...). The more red the color, the higher the electric field strength and the greater the insulation risk. The red curve in the figure is a typical discharge path, which intuitively shows the electric field distribution characteristics of the main insulating oil gap.

[0055] After the discharge path is constructed, the insulation performance of each path needs to be quantitatively evaluated. For each discharge path, the insulation margin of the discharge path is determined based on the electric field distribution of the discharge path.

[0056] Preferably, the insulation margin of the discharge path is determined based on the electric field distribution of the discharge path, including: Calculate the cumulative average electric field strength of the discharge path based on the electric field distribution along the discharge path. In the path diagram model, sampling points on the winding surface are extracted to form a set of winding nodes; The type of insulating medium interface traversed by the discharge path is determined based on the shortest distance from the sampling point in the discharge path to the set of winding nodes. Obtain the operating conditions of the natural ester transformer to be tested; The allowable average electric field strength of the discharge path is determined based on the operating conditions of the natural ester transformer to be tested and the type of insulating medium interface that the discharge path passes through. The insulation margin of the discharge path is determined by the ratio of the allowable average electric field strength to the cumulative average electric field strength.

[0057] Specifically, when determining the insulation margin of a discharge path, the first step is to consider the discharge path. The discharge path is calculated using the following formula, which corresponds to the electric field strength at each sampling point and the length of the corresponding segment. Cumulative average field strength: ; in, Indicates the discharge path The cumulative average field strength, Indicates sampling point The electric field strength at that location.

[0058] By weighting the electric field strength of each segment along the path according to the segment length, the cumulative average field strength is obtained, thus quantifying the overall electric field strength level of the path.

[0059] Subsequently, in the path graph model In the process, sampling points are extracted from the surface of the winding. This constitutes the winding node set. And set a distance threshold. This serves as a quantitative standard for judging the spatial relationship between the discharge path and the winding.

[0060] For the discharge path sampling points on Calculate its set of winding nodes. Find the Euclidean distances of all points and take the minimum value among them. This represents the sampling point. The shortest distance to the winding.

[0061] Then, determine whether there exists a shortest distance from the sampling point to the set of winding nodes in the discharge path. Less than the preset distance threshold .

[0062] If there exists a shortest distance from the sampling point to the set of winding nodes in the discharge path Less than the preset distance threshold ,Right now This indicates that the path is close to the winding, and the insulation boundary is directly connected to the winding. Therefore, the type of insulation medium interface traversed by the discharge path is determined to be the insulating paperboard-winding oil gap; where, For the set of winding nodes Sampling points on the surface of the intermediate winding; If there is no shortest distance from the sampling point to the winding node set in the discharge path Less than the preset distance threshold ,Right now If the path is far from the winding and the insulation boundary is made of insulating paperboard, then the type of the insulating medium interface that the discharge path passes through is determined to be insulating paperboard-insulating paperboard oil gap.

[0063] Furthermore, this invention, for natural ester insulating liquids, refers to the Weidmann allowable field strength curve and sets allowable average field strengths under different operating conditions and different insulating medium interface types. The details are as follows: Under power frequency voltage conditions, for vacuum-filled natural ester transformers, the average cumulative electric field strength of the oil gap between insulating paperboards should not exceed [the specified value]. ;in, This represents the allowable average electric field strength of the oil gap between insulating paperboards under power frequency voltage. Under power frequency voltage conditions, for vacuum-filled natural ester transformers, the average cumulative electric field strength of the oil gap between the insulating paperboard and the windings should not exceed [the specified value]. ;in, This represents the allowable average electric field strength of the oil gap between the insulating paperboard and the winding under power frequency voltage. Under lightning impulse voltage conditions, for vacuum-filled natural ester transformers, the average cumulative electric field strength of the oil gaps between insulating paperboards should not exceed [a certain value]. ;in, This represents the allowable average electric field strength of the oil gap between insulating paperboards under lightning impulse voltage. Under lightning impulse voltage conditions, for vacuum-filled natural ester transformers, the average cumulative electric field strength of the oil gap between the insulating paperboard and the windings should not exceed [the specified value]. ;in, This represents the allowable average electric field strength of the oil gap between the insulating paperboard and the winding under lightning impulse voltage.

[0064] After determining the type of the insulating medium interface in the discharge path, the actual operating conditions of the transformer are further obtained. The operating conditions directly reflect the type of electric field stress that the transformer is currently experiencing, such as whether it is under power frequency voltage conditions or lightning impulse voltage conditions.

[0065] Based on the operating conditions of the natural ester transformer under test and the type of insulating medium interface traversed by the discharge path, the corresponding calculation formula is selected from the above set of allowable average electric field strength calculation formulas, and the path length is substituted. The discharge path is obtained. Allowable mean field strength This value represents the upper limit of the safe average electric field strength that the oil gap can withstand under the current operating conditions and interface type.

[0066] Finally, based on the discharge path Allowable mean field strength With discharge path The cumulative average electric field strength is calculated using the following formula to obtain the discharge path. Insulation margin: ; in, Indicates the discharge path The smaller the insulation margin, the weaker the insulation performance of the path, and the higher the risk of discharge.

[0067] This invention distinguishes the types of insulation medium interfaces traversed by the discharge path by quantifying the spatial distance between the sampling point and the winding, and matches the corresponding insulation safety threshold with the actual operating conditions of the transformer, thereby effectively avoiding assessment deviations and making the location results of weak insulation links more consistent with the actual insulation conditions of the transformer, thus improving the accuracy of insulation risk assessment.

[0068] After calculating the insulation margin of each discharge path, the pheromone concentration is updated based on the insulation margin to guide the ant colony algorithm to search for the path with the weakest insulation performance more efficiently in the next iteration.

[0069] Preferably, the pheromone concentration is updated based on the insulation margin of each discharge path to obtain the updated pheromone concentration, including: Based on the pheromone evaporation coefficient, the current pheromone concentration of each discharge path is volatilized to obtain the pheromone concentration after volatilization. Based on the insulation margin of each discharge path, determine the pheromone increment of the edges traversed by each discharge path; The updated pheromone concentration is obtained by summing the pheromone concentration after evaporation with the pheromone increment.

[0070] Specifically, based on the pheromone evaporation coefficient For each discharge path, the edges it passes through Current pheromone concentration The pheromone concentration after evaporation was obtained by performing a volatilization process. This simulates the natural decay of pheromones over time, avoids excessive interference from historical path information in subsequent searches, and ensures that the algorithm can continuously explore new potentially high-risk paths.

[0071] According to each discharge path insulation margin Determine the pheromone increment of each discharge path along its edges. If the side Belongs to the discharge path The pheromone increment is Otherwise, it is 0. Due to insulation margin The smaller the value, the better the discharge path. The higher the risk of discharge, the greater the corresponding pheromone increment, thereby enhancing the guidance of high-risk paths.

[0072] After calculating the pheromone increment, the concentration of the pheromone after evaporation will be... With all the ants on the edge The increase in pheromones left on Summing is performed to obtain the updated pheromone concentration. The specific update formula is as follows: ; ; in, Indicates the first The discharge path constructed by a single ant. Indicates the first Only ants on the side The increase in pheromones left on the surface.

[0073] Updated pheromone concentration The current pheromone concentration serves as the basis for the next ant colony search process, guiding the path selection of the next round of ants.

[0074] When the ant colony search process reaches its maximum iteration count... At this point, the ant colony search process terminates, and the discharge path with the minimum insulation margin is output: ; in, This represents the discharge path with the minimum insulation margin.

[0075] Finally, the discharge path with the smallest insulation margin is selected. As a potential discharge path in the main insulating oil gap, the corresponding discharge path insulation margin Minimum insulation margin .

[0076] This invention uses an ant colony algorithm to update pheromone concentration based on insulation margin, enabling paths with higher discharge risk to receive stronger pheromone guidance. Through repeated iterations, pheromone continuously converges towards high-risk paths, and the algorithm gradually focuses on the weakest area of ​​insulation performance. This effectively achieves precise location of weak points in the insulation of natural ester transformers and improves the accuracy of insulation risk assessment.

[0077] Step S7: Evaluate the insulation performance of the natural ester transformer under test based on the insulation margin of the potential discharge path.

[0078] In a preferred embodiment, the insulation performance of the natural ester transformer under test is evaluated based on the insulation margin of potential discharge paths, including: The insulation margin of potential discharge paths is compared with a preset insulation threshold. If the insulation margin of a potential discharge path is greater than the preset insulation threshold, the insulation performance of the natural ester transformer to be tested is determined to be free of main insulation discharge risk. If the insulation margin of a potential discharge path is less than or equal to a preset insulation threshold, the insulation performance of the natural ester transformer under test is determined to have a risk of main insulation discharge.

[0079] For step S7, after determining the potential discharge path in the main insulating oil gap through step S6, the insulation margin of the potential discharge path is... With preset insulation threshold Compare them.

[0080] When the insulation margin of the potential discharge path Greater than the preset insulation threshold ,Right now At that time, explain the potential discharge path. The actual average field strength is lower than the safety allowable value, and the insulation strength meets the operating requirements. Therefore, it is determined that the insulation performance of the natural ester transformer to be tested does not pose a risk of main insulation discharge.

[0081] When the insulation margin of the potential discharge path Less than or equal to the preset insulation threshold ,Right now At that time, explain the potential discharge path. The actual average field strength has reached or exceeded the safety allowable value, the insulation strength is insufficient, and there is a risk of discharge. Therefore, it is determined that the insulation performance of the natural ester transformer to be tested has a risk of main insulation discharge.

[0082] In this embodiment, the preset insulation threshold is 1. The specific value can be adaptively adjusted and set according to actual engineering needs, insulation material characteristics and test data.

[0083] In a preferred embodiment, after evaluating the insulation performance of the natural ester transformer under test based on the insulation margin of the potential discharge path, the method further includes: Given that the insulation performance of the natural ester transformer under test poses a risk of main insulation discharge, suggestions for optimizing the insulation structure are generated.

[0084] In one embodiment of the present invention, step S7 determines that the insulation performance of the natural ester transformer to be tested is at risk of main insulation discharge, and then generates insulation structure optimization suggestions.

[0085] For example, if the potential discharge path passes through the insulating paperboard-winding interface, it is recommended to increase the number of insulating paperboard layers or increase the oil gap length between the winding and the paperboard to improve the insulation withstand capability of the area and thus reduce the risk of discharge. If a potential discharge path passes through an insulating paperboard-insulating paperboard interface, it is recommended to increase the number of insulating paperboards or adjust the spacing between them to optimize the electric field distribution and enhance the insulation performance at the interface.

[0086] Finally, the insulation performance was reassessed based on the newly designed transformer structure.

[0087] like Figure 3 As shown, based on the above method embodiments, corresponding apparatus embodiments are provided; An embodiment of the present invention provides an insulation performance evaluation device for the main insulation of a natural ester transformer, comprising: a finite element model construction module, a finite element model simulation module, a path graph model construction module, a path graph node determination module, a parameter initialization module, an ant colony search module, and an insulation performance evaluation module; The finite element model building module is used to obtain the structural parameters of the natural ester transformer to be tested and to build a two-dimensional axisymmetric model. The finite element model simulation module is used to perform electric field finite element simulation on a two-dimensional axisymmetric model to obtain the electric field distribution in the main insulating oil gap region. The path graph model building module is used to build a path graph model based on the electric field distribution in the main insulating oil gap region. The path graph node determination module is used to determine path graph nodes based on the path graph model; path graph nodes are used to represent discrete positions that ants can choose from. The parameter initialization module is used to initialize ant colony parameters, including: initial pheromone concentration and maximum number of iterations. The ant colony search module is used to repeatedly execute the ant colony search process until the maximum number of iterations is reached, and the discharge path with the smallest insulation margin is selected as the potential discharge path in the main insulating oil gap. The ant colony search process includes: for each ant, constructing a discharge path based on the current pheromone concentration and path graph nodes; for each discharge path, determining the insulation margin of the discharge path based on the electric field distribution of the discharge path; updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration; and using the updated pheromone concentration as the current pheromone concentration for the next execution of the ant colony search process; wherein, the current pheromone concentration when the ant colony search process is executed for the first time is the initial pheromone concentration. The insulation performance evaluation module is used to evaluate the insulation performance of the natural ester transformer under test based on the insulation margin of potential discharge paths.

[0088] In a preferred embodiment, the path graph model construction module includes: a discrete sampling unit, an adjacent edge generation unit, an edge set generation unit, and a path graph model generation unit; Discrete sampling unit is used to perform discrete sampling in the main insulating oil gap region, and extract the spatial position and electric field intensity of each sampling point to construct the main insulating oil gap sampling point set; The adjacent edge generation unit is used to calculate the Euclidean distance between the two sampling points in each sampling point pair based on their spatial positions, and to establish an edge between the two sampling points in the sampling point pair if the Euclidean distance does not exceed a preset distance; the sampling point pair consists of any two distinct sampling points in the main insulating oil gap sampling point set. The edge set generation unit is used to traverse all sampling point pairs in the main insulating oil gap sampling point set and form an edge set from all edges. The path graph model generation unit is used to generate a path graph model based on the main insulating oil gap sampling point set and edge set.

[0089] In a preferred embodiment, the ant colony search module constructs a discharge path based on the current pheromone concentration and path graph nodes, including: Place the ant at the initial node; the initial node is the starting point of the pre-defined discharge path in the path graph node; Repeat the path expansion process to obtain the discharge path; The path expansion process includes: From the edge set, obtain all adjacent nodes that are adjacent to the current node; among them, the current node during the first execution of the path expansion process is the initial node; For each adjacent node, the heuristic function value of the edge formed by the current node and the adjacent nodes is obtained based on the electric field strength of the current node. Calculate the transition probability from the current node to the neighboring node based on the current pheromone concentration and heuristic function value on the edge formed by the current node and its neighboring nodes. From all the transition probabilities of adjacent nodes, select the adjacent node with the highest probability value as the next node; Determine if the next node is the endpoint node. If it is, then the initial node, all selected next nodes, and their corresponding edges form the discharge path. If not, the next node is used as the current node for the next path expansion process. The endpoint node is the pre-defined endpoint of the discharge path in the path graph node.

[0090] In a preferred embodiment, the ant colony search module determines the insulation margin of the discharge path based on the electric field distribution of the discharge path, including: Calculate the cumulative average electric field strength of the discharge path based on the electric field distribution along the discharge path. In the path diagram model, sampling points on the winding surface are extracted to form a set of winding nodes; The type of insulating medium interface traversed by the discharge path is determined based on the shortest distance from the sampling point in the discharge path to the set of winding nodes. Obtain the operating conditions of the natural ester transformer to be tested; The allowable average electric field strength of the discharge path is determined based on the operating conditions of the natural ester transformer to be tested and the type of insulating medium interface that the discharge path passes through. The insulation margin of the discharge path is determined by the ratio of the allowable average electric field strength to the cumulative average electric field strength.

[0091] In a preferred embodiment, the ant colony parameters further include: pheromone evaporation coefficient; The ant colony search module updates the pheromone concentration based on the insulation margin of each discharge path, obtaining the updated pheromone concentration, including: Based on the pheromone evaporation coefficient, the current pheromone concentration of each discharge path is volatilized to obtain the pheromone concentration after volatilization. Based on the insulation margin of each discharge path, determine the pheromone increment of the edges traversed by each discharge path; The updated pheromone concentration is obtained by summing the pheromone concentration after evaporation with the pheromone increment.

[0092] In a preferred embodiment, the insulation performance evaluation module includes: an insulation threshold comparison unit, a first risk determination unit, and a second risk determination unit; An insulation threshold comparison unit is used to compare the insulation margin of a potential discharge path with a preset insulation threshold. The first risk determination unit is used to determine that the insulation performance of the natural ester transformer under test does not have a risk of main insulation discharge if the insulation margin of the potential discharge path is greater than the preset insulation threshold. The second risk assessment unit is used to determine that the insulation performance of the natural ester transformer under test has a risk of main insulation discharge if the insulation margin of the potential discharge path is less than or equal to the preset insulation threshold.

[0093] In a preferred embodiment, the insulation performance evaluation device for the main insulation of a natural ester transformer further includes: an optimization suggestion generation module; The optimization suggestion generation module is used to generate insulation structure optimization suggestions when the insulation performance of the natural ester transformer under test is at risk of main insulation discharge.

[0094] It is understood that the above-described device embodiments correspond to the method embodiments of the present invention, and can implement the insulation performance evaluation method for the main insulation of the natural ester transformer provided by any of the above-described method embodiments of the present invention.

[0095] It should be noted that the device embodiments described above are merely illustrative, and some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can specifically be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0096] Based on the above embodiments of the method for evaluating the insulation performance of the main insulation of a natural ester transformer, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the method for evaluating the insulation performance of the main insulation of a natural ester transformer according to any embodiment of the present invention.

[0097] For example, in this embodiment, the computer program can be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the terminal device.

[0098] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0099] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting various parts of the terminal device via various interfaces and lines.

[0100] Based on the above-described method embodiments, another embodiment is provided: another embodiment of the present invention provides a computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute the insulation performance evaluation method for the main insulation of the natural ester transformer as described in any of the above-described method embodiments of the present invention.

[0101] The module / unit integrated into the insulation performance evaluation device / terminal equipment for the main insulation of the natural ester transformer, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0102] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for evaluating the insulation performance of the main insulation of a natural ester transformer, characterized in that, include: Obtain the structural parameters of the natural ester transformer to be tested and construct a two-dimensional axisymmetric model; The electric field distribution in the main insulating oil gap region was obtained by performing finite element simulation on a two-dimensional axisymmetric model. Based on the electric field distribution in the main insulating oil gap region, a path diagram model is constructed; Based on the path graph model, path graph nodes are determined; these path graph nodes are used to represent discrete locations that ants can choose from. Initialize ant colony parameters; the ant colony parameters include: initial pheromone concentration and maximum number of iterations; The ant colony search process is repeated until the maximum number of iterations is reached. The discharge path with the smallest insulation margin is selected as the potential discharge path in the main insulating oil gap. The ant colony search process includes: for each ant, constructing a discharge path based on the current pheromone concentration and path graph nodes; for each discharge path, determining the insulation margin based on the electric field distribution of the discharge path; updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration; and using the updated pheromone concentration as the current pheromone concentration for the next execution of the ant colony search process. The current pheromone concentration during the first execution of the ant colony search process is the initial pheromone concentration. The insulation performance of the natural ester transformer under test is evaluated based on the insulation margin of the potential discharge path.

2. The method for evaluating the insulation performance of the main insulation of a natural ester transformer according to claim 1, characterized in that, Based on the electric field distribution in the main insulating oil gap region, a path diagram model is constructed, including: Discrete sampling is performed within the main insulating oil gap region, and the spatial location and electric field intensity of each sampling point are extracted to construct the main insulating oil gap sampling point set; For each pair of sampling points, the Euclidean distance is calculated based on the spatial position of the two sampling points in the pair, and an edge is established between the two sampling points corresponding to the pair if the Euclidean distance does not exceed a preset distance; the pair of sampling points consists of any two distinct sampling points in the set of main insulating oil gap sampling points. Traverse all sampling point pairs in the main insulating oil gap sampling point set and construct an edge set from all edges; A path graph model is generated based on the main insulating oil gap sampling point set and edge set.

3. The method for evaluating the insulation performance of the main insulation of a natural ester transformer according to claim 2, characterized in that, Based on the current pheromone concentration and path graph nodes, construct the discharge path, including: Place the ant at the initial node; the initial node is the starting point of the pre-defined discharge path in the path graph node; Repeat the path expansion process to obtain the discharge path; The path expansion process includes: From the edge set, obtain all adjacent nodes that are adjacent to the current node; among them, the current node during the first execution of the path expansion process is the initial node; For each adjacent node, the heuristic function value of the edge formed by the current node and the adjacent nodes is obtained based on the electric field strength of the current node. Calculate the transition probability from the current node to the neighboring node based on the current pheromone concentration and heuristic function value on the edge formed by the current node and its neighboring nodes. From all the transition probabilities of adjacent nodes, select the adjacent node with the highest probability value as the next node; Determine whether the next node is the endpoint node. If it is, then the initial node, all selected next nodes, and their corresponding edges form a discharge path. If not, the next node is used as the current node for the next path expansion process. The endpoint node is the pre-defined endpoint of the discharge path in the path graph node.

4. The method for evaluating the insulation performance of the main insulation of a natural ester transformer according to claim 1, characterized in that, Based on the electric field distribution along the discharge path, determine the insulation margin of the discharge path, including: Calculate the cumulative average electric field strength of the discharge path based on the electric field distribution along the discharge path. In the path diagram model, sampling points on the winding surface are extracted to form a set of winding nodes; The type of insulating medium interface traversed by the discharge path is determined based on the shortest distance from the sampling point in the discharge path to the set of winding nodes. Obtain the operating conditions of the natural ester transformer to be tested; The allowable average electric field strength of the discharge path is determined based on the operating conditions of the natural ester transformer to be tested and the type of insulating medium interface that the discharge path passes through. The insulation margin of the discharge path is determined by the ratio of the allowable average electric field strength to the cumulative average electric field strength.

5. The method for evaluating the insulation performance of the main insulation of a natural ester transformer according to claim 1, characterized in that, The ant colony parameters also include: pheromone evaporation coefficient; The step of updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration includes: Based on the pheromone evaporation coefficient, the current pheromone concentration of each discharge path is volatilized to obtain the pheromone concentration after volatilization. Based on the insulation margin of each discharge path, determine the pheromone increment of the edges traversed by each discharge path; The updated pheromone concentration is obtained by summing the pheromone concentration after evaporation with the pheromone increment.

6. The method for evaluating the insulation performance of the main insulation of a natural ester transformer according to claim 1, characterized in that, The insulation performance of the natural ester transformer under test is evaluated based on the insulation margin of the potential discharge path, including: The insulation margin of potential discharge paths is compared with a preset insulation threshold. If the insulation margin of a potential discharge path is greater than the preset insulation threshold, the insulation performance of the natural ester transformer to be tested is determined to be free of main insulation discharge risk. If the insulation margin of a potential discharge path is less than or equal to a preset insulation threshold, the insulation performance of the natural ester transformer under test is determined to have a risk of main insulation discharge.

7. The method for evaluating the insulation performance of the main insulation of a natural ester transformer according to claim 6, characterized in that, After assessing the insulation performance of the natural ester transformer under test based on the insulation margin of the potential discharge path, the following steps are also included: Given that the insulation performance of the natural ester transformer under test poses a risk of main insulation discharge, suggestions for optimizing the insulation structure are generated.

8. An insulation performance evaluation device for the main insulation of a natural ester transformer, characterized in that, include: The module includes a finite element model construction module, a finite element model simulation module, a path graph model construction module, a path graph node determination module, a parameter initialization module, an ant colony search module, and an insulation performance evaluation module. The finite element model construction module is used to obtain the structural parameters of the natural ester transformer to be tested and construct a two-dimensional axisymmetric model. The finite element model simulation module is used to perform electric field finite element simulation on a two-dimensional axisymmetric model to obtain the electric field distribution in the main insulating oil gap region. The path graph model construction module is used to construct a path graph model based on the electric field distribution in the main insulating oil gap region. The path graph node determination module is used to determine path graph nodes based on the path graph model; the path graph nodes are used to represent discrete positions that can be selected by ants. The parameter initialization module is used to initialize ant colony parameters; the ant colony parameters include: initial pheromone concentration and maximum number of iterations; The ant colony search module is used to repeatedly execute the ant colony search process until the maximum number of iterations is reached, and to select the discharge path with the smallest insulation margin as the potential discharge path in the main insulating oil gap. The ant colony search process includes: for each ant, constructing a discharge path based on the current pheromone concentration and path graph nodes; for each discharge path, determining the insulation margin of the discharge path based on the electric field distribution of the discharge path; updating the pheromone concentration based on the insulation margin of each discharge path to obtain the updated pheromone concentration; and using the updated pheromone concentration as the current pheromone concentration for the next execution of the ant colony search process; wherein, the current pheromone concentration when the ant colony search process is executed for the first time is the initial pheromone concentration. The insulation performance evaluation module is used to evaluate the insulation performance of the natural ester transformer under test based on the insulation margin of the potential discharge path.

9. A terminal device, characterized in that, The device includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements the insulation performance evaluation method for the main insulation of a natural ester transformer as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device on which the computer-readable storage medium is located to perform the insulation performance evaluation method for the main insulation of a natural ester transformer as described in any one of claims 1-7.

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