A method for analyzing the spatial electric field of a power take-off capacitor of a pole-mounted circuit breaker

Abstract

The application discloses a space electric field analysis method for internal and external placement of a power-taking capacitor of a pole-mounted circuit breaker, and relates to the technical field of pole-mounted circuit breaker analysis.The method comprises the following steps: constructing a finite element simulation model based on the structure of a pole-mounted circuit breaker and simulation equipment, which is more in line with the actual structure; obtaining first electric field distribution data and the position of a target element based on the finite element simulation model; drawing a first cross-section electric field based on the position, the first electric field distribution data, material data of the pole-mounted circuit breaker and boundary conditions of the electrostatic field; obtaining an electric field concentration position and an electric field distortion point based on the first electric field intensity of the cross-section electric field; constructing a three-dimensional cross-section line based on the electric field concentration position and the electric field distortion point; analyzing the electric field based on the three-dimensional cross-section line; and obtaining an analysis result, which can solve the problem that the position setting of the power-taking capacitor in an existing complete pole-mounted circuit breaker device is unreasonable, influences the internal electric field distribution of the pole, and leads to electric field distortion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pole-mounted circuit breaker analysis, in particular to a method and system for analyzing the spatial electric field of an internal or external power-taking capacitor of a pole-mounted circuit breaker. BACKGROUND

[0002] As a commonly used protection and control device in power distribution network power systems, the performance and reliability of the pole-mounted circuit breaker directly relate to the safe and stable operation of the power grid. With the continuous deepening of the pole-mounted circuit breaker primary and secondary fusion and the continuous increase of high-voltage components in the pole-mounted circuit breaker pole, the commonly used capacitor power-taking mode in the complete pole-mounted circuit breaker device has many different schemes in the connection and cooperation mode with the pole-mounted circuit breaker body, such as internal or external pole-mounted circuit breaker power-taking capacitor. However, in the existing complete pole-mounted circuit breaker device, the internal power-taking capacitor in the pole reduces the device volume, but if the position is not reasonably set, it will affect the internal electric field distribution of the pole, especially the mutual influence of the electric field between multiple high-voltage components, which may cause electric field distortion, thereby increasing the difficulty and cost of insulation design. SUMMARY

[0003] In order to solve the problem of unreasonable position setting of the power-taking capacitor in the existing complete pole-mounted circuit breaker device, affecting the internal electric field distribution of the pole, and causing electric field distortion, the present application provides a method for analyzing the spatial electric field of an internal or external power-taking capacitor of a pole-mounted circuit breaker, which comprises:

[0004] Based on the structure of the pole-mounted circuit breaker and the simulation device, a finite element simulation model is constructed, which is more consistent with the actual structure. Based on the finite element simulation model, first electric field distribution data and the position of the target element are obtained. Based on the position, the first electric field distribution data, the material data of the pole-mounted circuit breaker, and the boundary conditions of the electrostatic field, a first cross-section electric field is drawn. Based on the first electric field strength of the cross-section electric field, the electric field concentration position and the electric field distortion point are obtained. Based on the electric field concentration position and the electric field distortion point, a three-dimensional cross-section line is constructed. Based on the three-dimensional cross-section line, the electric field is analyzed, and the analysis result is obtained.

[0005] The application builds a finite element simulation model of the internal space of the pole-mounted circuit breaker, adjusts and arranges the finite element model according to different design structures of the pole-mounted circuit breaker, establishes a cross-section electric field of a target element according to material data of the pole-mounted circuit breaker and boundary conditions of the electrostatic field, sets the material of each element in the simulation model according to the actual material of the pole-mounted circuit breaker, is more close to the actual situation, the electric field distribution is more accurate, analyzes the electric field concentration points and electric field distortion positions around the target element, establishes a three-dimensional section line of the space electric field distribution of the target element, analyzes the change law of the electric field strength around the target element with the physical position, and then adjusts the position of the target element, reduces the influence of the internal electric field of the pole and the electric field distortion, can more reasonably set the position of the target element, and provides theoretical guidance for the design of the pole-mounted circuit breaker.

[0006] In the cross-section electric field analysis, the electric field concentration position and the electric field distortion position represent the places with relatively large electric field strength in the whole model calculation. In the insulation field, the position with relatively large electric field strength and the electric field distortion will first produce partial discharge under long-term high-voltage operation, and cause aging influence on the equipment insulation. Therefore, when analyzing the electric field of the model by the finite element, it is necessary to start from the electric field concentration position and the electric field distortion position, the electric field change of which is obvious, and a three-dimensional section line is further constructed at the position to analyze the three-dimensional section line data, which is more obvious and easier to observe.

[0007] In actual operation, compared with other positions, the parts with relatively large electric field strength or serious electric field distortion of the insulation material or the elements of the equipment will first produce partial discharge under long-term high-voltage operation or transient lightning impact, and cause damage to the insulation. The electric field concentration point and the electric field distortion point are prone to insulation breakdown in actual use, and need additional insulation design. Analyzing the two positions is more convenient for comparing the difficulty of insulation design of the target element under different setting positions, so as to obtain the advantages and disadvantages of different design methods.

[0008] The finite element model can convert a large problem that cannot be directly calculated and analyzed in practice into several small problems that can be calculated and analyzed by finite element segmentation. Through the calculation of several small problems, the calculation result of the large problem is approximately obtained. The mesh division technology of the finite element technology converts a large model into several small models by mesh division, accurately calculates the small models, and approximately obtains the calculation result of the large model.

[0009] Further, the specific steps of analyzing the electric field based on the three-dimensional section line to obtain an analysis result include: obtaining a second electric field strength of the three-dimensional section line, constructing a longitudinal cross-section electric field based on the second electric field strength and a preset distance, analyzing an electric field distribution law based on the longitudinal cross-section electric field and the first cross-section electric field, and obtaining the analysis result.

[0010] In addition to passing through the capacitor, the transverse section also passes through the conductive rod and the current transformer coil model, and the corresponding cut point electric field extreme value analysis is likely to be affected by the above factors; and the transverse section does not include the target element model and the space part model corresponding to the target element in the electric field cutting process, so the longitudinal section electric field is constructed in the application.

[0011] Further, the specific steps of obtaining the first electric field distribution data based on the finite element simulation model include:

[0012] The number of target elements is obtained, the voltage value of the target element is set based on the number and the preset limit voltage value, and the first electric field distribution data is obtained based on the voltage value.

[0013] Further, the preset limit voltage value is

[0014] The worst case in practice is analyzed by simulating the limit case, and the commonly used withstand voltage experiment power supply is 42kV power frequency voltage, and the maximum voltage value that may occur under this condition is the peak value of the sine voltage, that is, Considering that the energy taking capacitor is usually fixedly installed at present, but the fixedly installed capacitor will cause the electric field distortion coefficient to fluctuate under different working conditions, such as temperature change, mechanical vibration or change of surrounding electromagnetic environment, thereby affecting the stability and performance of the equipment. The application establishes a dynamic four-dimensional electric field model containing time dimension, collects the spatial electric field distribution in real time through a multi-modal sensor, obtains the optimal position of the energy taking capacitor according to the dynamic four-dimensional electric field model and the finite element simulation model, adjusts the energy taking capacitor to the optimal position through an adjusting device, dynamically adjusts the position of the energy taking capacitor according to different working conditions, reduces the internal electric field non-uniformity coefficient of the pole, reduces the fluctuation of the electric field distortion coefficient, and improves the stability and performance of the equipment. Further, the method further includes: obtaining the operating state parameters of the pole of the pole-mounted circuit breaker and second electric field distribution data, fusing the operating state parameters and the second electric field distribution data to obtain fusion data; constructing a four-dimensional electric field model of the pole based on the fusion data and the finite element simulation model; obtaining an optimal position based on the four-dimensional electric field model, obtaining an adjustment amount based on the optimal position, adjusting the position of the capacitor based on the adjustment amount, and adjusting the spatial electric field distribution inside the pole.

[0015] Considering the dynamic temperature field-mechanical stress field-electromagnetic field multi-physical field coupling effect of the equipment during operation, the internal three-dimensional space coordinates of the pole are obtained through a finite element simulation model, the fourth dimension is constructed based on the time axis and the operating state parameters, and a four-dimensional electric field model is obtained, so that the multi-physical field is decoupled in real time, the optimal position of the energy taking capacitor position is found through the four-dimensional electric field model, and the uniformity of the electric field distribution inside the pole is improved, and the electric field distortion problem is reduced.

[0016] Further, the operating state parameters and the second electric field distribution data are acquired based on a multi-modal sensor, the operating state parameters include temperature, mechanical stress and load current; the multi-modal sensor includes an electric field sensor, a temperature sensor and a strain gauge, the electric field sensor is used to collect spatial electric field distribution, the temperature sensor is used to collect temperature, and the strain gauge is used to collect mechanical stress; the electric field sensor is spirally distributed on the inner surface of the pole column, the temperature sensor is built-in in the pole column, and the strain gauge is installed on the fixing device of the energy-taking capacitor.

[0017] Considering that the materials (such as aluminum alloy, stainless steel and silicone rubber) of the internal elements of the pole column change nonlinearly under temperature cycles, the softening or expansion of the materials at high temperature causes the change of the three-dimensional coordinates of the pole column, which may cause the optimal position of the energy-taking capacitor to conflict with the elements or be inaccurate, the material property database is established, the dynamic interaction of the temperature field, the mechanical stress field and the electromagnetic field is considered, the error accumulation of the traditional single field analysis is avoided, the temperature-dependent elastic modulus and thermal expansion coefficient are introduced on the basis of the standard form, that is, the temperature effect and the nonlinear characteristics of the materials are introduced, the influence of the thermal stress on the position of the capacitor is more accurately calculated, the three-dimensional coordinates of the internal space of the pole column are more accurately obtained, and then the optimal position of the energy-taking capacitor is more accurately obtained.

[0018] Further, a material database is constructed, the material database includes a plurality of materials, each material corresponds to a Poisson's ratio, an elastic modulus and a thermal expansion coefficient at different temperatures; a strain and a deformation are obtained based on the temperature, the mechanical stress and the material database, the four-dimensional electric field model is updated based on the strain and the deformation, and the adjustment amount is obtained based on the updated four-dimensional electric field model.

[0019] The calculation formula of the strain is:

[0020]

[0021] Wherein, σ represents mechanical stress, E represents elastic modulus, v represents Poisson's ratio, ε represents strain tensor, k represents volume strain, α represents thermal expansion coefficient, ΔT represents temperature change, and δ represents unit tensor.

[0022] Further, based on the adjustment amount, an adjusting device adjusts the position of the capacitor, the adjusting device includes a base, a piezoelectric ceramic and a motion platform, the piezoelectric ceramic is installed on the base, the top of the piezoelectric ceramic is connected with the bottom of the motion platform, and the capacitor is installed on the motion platform; a driving voltage is obtained based on the adjustment amount, the driving voltage is input to the piezoelectric ceramic, the piezoelectric ceramic generates displacement along the axial direction, pushes the motion platform, and adjusts the position of the capacitor to the optimal position.

[0023] The voltage signal is converted into precise displacement through the inverse piezoelectric effect of the piezoelectric ceramic. After the voltage is applied, the internal lattice structure of the piezoelectric ceramic deforms, and the piezoelectric ceramic material (such as PZT-8) deforms, expands along the axial direction, generates mechanical displacement, and pushes the motion platform to move axially, thereby realizing real-time change of the position of the energy harvesting capacitor.

[0024] The piezoelectric ceramic may generate lateral force or torque during movement, affecting positioning accuracy. The present application transmits the linear displacement of the piezoelectric ceramic to the load without deviation through the guide mechanism, provides friction-free and gap-free guidance, suppresses lateral swing, limits non-axial degrees of freedom (such as lateral deviation or rotation), and reduces lateral force interference.

[0025] Further, the top of the piezoelectric ceramic is connected to the bottom of the motion platform through a stress concentration mechanism, the base and the motion platform are connected through a guide mechanism, and the piezoelectric ceramic and the base are connected through a pre-tightening force adjustment module.

[0026] The pre-tightening force adjustment module ensures that the piezoelectric ceramic is always in a compressed state, avoids backlash gaps, applies controllable static pressure, eliminates mechanical gaps, suppresses mechanical hysteresis, and protects the piezoelectric ceramic from tensile damage.

[0027] The stress concentration mechanism uniformly transmits the concentrated force of the piezoelectric ceramic to the motion platform, reduces contact stress concentration, and avoids local stress damage.

[0028] Further, the stress concentration mechanism is a hemispherical ceramic gasket, the guide mechanism is a flexible hinge, and the pre-tightening force adjustment module is a disc spring. The flexible hinge can provide high-precision guidance while allowing small displacement to avoid friction and wear.

[0029] The hemispherical ceramic gasket reduces contact stress concentration while reducing friction and assembly errors through spherical contact, improves displacement transmission efficiency, and the thermal expansion coefficient of ceramic material is low, reducing the influence of temperature change on the contact interface.

[0030] The one or more technical solutions provided by the present application have at least the following technical effects or advantages:

[0031] 1. The finite element simulation model of the internal space of the pole-mounted circuit breaker is built, the finite element model is adjusted and arranged according to different design structures of the pole-mounted circuit breaker, the cross-section electric field of the target element is established according to the material data of the pole-mounted circuit breaker and the boundary conditions of the electrostatic field, the materials of each element in the simulation model are set according to the actual materials of the pole-mounted circuit breaker, which is more realistic and more accurate in electric field distribution, and the electric field concentration points and the electric field distortion positions around the target element are analyzed, the three-dimensional section lines of the space electric field distribution of the target element are established, the variation law of the electric field strength around the target element with the physical position is analyzed, and then the position of the target element is adjusted to reduce the influence of the internal electric field of the pole and the electric field distortion, the position of the target element can be more reasonably set, and theoretical guidance is provided for the design of the pole-mounted circuit breaker.

[0032] 2. The electric field changes obviously at the electric field concentration position and the electric field distortion position, and the three-dimensional section lines are further constructed at the positions, and the data of the three-dimensional section lines are analyzed, which is more obvious and easier to observe.

[0033] 3. The electric field concentration point and the electric field distortion point are prone to insulation breakdown in actual use, and additional insulation design is needed, the two positions are analyzed, which is more convenient for comparing the difficulty of insulation design of the target element at different setting positions, so as to obtain the advantages and disadvantages of different design methods.

[0034] 4. The optimal position of the energy-taking capacitor is obtained according to the four-dimensional electric field model and the finite element simulation model, the energy-taking capacitor is adjusted to the optimal position by the adjusting device, the position of the energy-taking capacitor is dynamically adjusted according to different working conditions, the internal electric field non-uniformity coefficient of the pole is reduced, the fluctuation of the electric field distortion coefficient is reduced, and the stability and performance of the equipment are improved. BRIEF DESCRIPTION OF DRAWINGS

[0035] The drawings described herein are used to provide further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation on the embodiments of the present application;

[0036] Figure 1 is a flowchart of a space electric field analysis method for an internal and external energy-taking capacitor of a pole-mounted circuit breaker in the present application;

[0037] Figure 2 is a finite element simulation model structure diagram of an internal energy-taking capacitor pole;

[0038] Figure 3 is a finite element simulation model structure diagram of an external energy-taking capacitor pole;

[0039] Figure 4 is a top view of the finite element simulation model of the internal energy-taking capacitor pole;

[0040] Figure 5is a top view of a finite element simulation model of an external pole of a power take-off capacitor;

[0041] Figure 6 is a three-dimensional cross-sectional schematic diagram;

[0042] Figure 7 is a schematic diagram of the longitudinal physical distance distribution of the electric field at the position of the upper stacked sampling capacitor a;

[0043] Figure 8 is a schematic diagram of the longitudinal physical distance distribution of the electric field at the position of the upper stacked sampling capacitor b;

[0044] Figure 9 is a schematic diagram of the longitudinal physical distance distribution of the electric field at the position of the upper stacked sampling capacitor c;

[0045] Figure 10 is a schematic diagram of the longitudinal physical distance distribution of the electric field at the position of the upper stacked sampling capacitor d;

[0046] wherein 1 is a stacked sampling capacitor, 2 is a wound power take-off capacitor, 3 is a current transformer coil wire package, 4 is a pole outgoing line side conductive rod of a pole-mounted circuit breaker, 5 is a grounding rod, and a, b, c, and d represent four corner points of the stacked sampling capacitor. DETAILED DESCRIPTION

[0047] In order to enable a more clear understanding of the above-mentioned objects, features and advantages of the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0048] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other ways different from those described herein within the scope of the present application, therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0049] Embodiment One

[0050] Reference Figures 1-10 The embodiment provides a spatial electric field analysis method for an internal and external power take-off capacitor of a pole-mounted circuit breaker, and the method comprises the following steps:

[0051] A finite element simulation model is constructed based on the structure of the pole-mounted circuit breaker and a simulation device. In the embodiment, the simulation device can be an AC / DC module of COMSOL Multiphysics.

[0052] Obtaining the first electric field distribution data and the position of the target element based on the finite element simulation model; the specific steps of obtaining the first electric field distribution data based on the finite element simulation model include: obtaining the number of the target elements, setting the voltage value of the target elements based on the number and the preset limit voltage value, such as assigning the voltage value of each target element in proportion to the number and the limit voltage value, for example, if the voltage value is 20 and the number is 5, then the voltage values are 20, 15, 10 and 5 respectively, based on the voltage value, obtaining the first electric field distribution data in the simulation calculation of the simulation device.

[0053] Drawing the first cross-sectional electric field based on the position, the first electric field distribution data, the material data of the pole-mounted circuit breaker and the boundary conditions of the electrostatic field.

[0054] Obtaining the electric field concentration position and the electric field distortion point based on the first electric field intensity of the cross-sectional electric field; for example, in the AC / DC module of COMSOL Multiphysics, obtaining the electric field intensity from the electric field numerical graph, obtaining the point with the maximum electric field intensity or the point with the highlighted position (in the cross-sectional electric field, the red highlighted point represents the position with large electric field intensity), thereby obtaining the electric field concentration position; obtaining the electric field distortion point through the numerical change of the electric field, such as the numerical change being greater than the preset numerical value.

[0055] Constructing a three-dimensional section line based on the electric field concentration position and the electric field distortion point;

[0056] Analyzing the electric field based on the three-dimensional section line to obtain an analysis result, the specific steps including: obtaining the second electric field intensity of the three-dimensional section line, constructing a longitudinal cross-sectional electric field based on the second electric field intensity and the preset distance, analyzing the electric field distribution law based on the longitudinal cross-sectional electric field and the first cross-sectional electric field to obtain the analysis result; for example, extracting the electric field intensity on the three-dimensional section line, establishing the electric field distribution along the longitudinal physical distance, and analyzing the electric field distribution law in combination with the first cross-sectional electric field.

[0057] The preset limit voltage value is

[0058] The cross-sectional electric field refers to the electric field generated on the cutting surface due to the redistribution of electric charges after the object is cut. This electric field phenomenon can be explained by electrostatic principles, that is, the redistribution of electric charges on the surface of the object leads to the formation of a specific electric field distribution on the cutting surface.

[0059] The three-dimensional section line refers to a line segment in three-dimensional space determined by a specific direction and an endpoint, used to intercept or divide a specific part of a three-dimensional model.

[0060] The AC / DC module of COMSOL Multiphysics is a professional tool for analyzing static and low-frequency electromagnetic problems, providing rich modeling functions and numerical methods to help users delve into electromagnetic fields and EMI / EMC problems by solving Maxwell's equations.

[0061] The boundary conditions of electrostatic field refer to some conditions that need to be met between different media or different regions in the same medium in electrostatic field analysis. These conditions are used to solve the potential difference and electric field strength generated between different media or regions.

[0062] The finite element model is a model established when using finite element analysis method, which is a combination of elements connected only at nodes, transmitting force only through nodes, and constrained only at nodes.

[0063] The electric field distortion point refers to the position in the electric field where the electric field distribution changes significantly due to certain factors. The electric field concentration point refers to the position in the electric field where the electric field strength is the largest.

[0064] Example 2

[0065] Reference Figures 1-10 On the basis of the above examples, in this embodiment, the position selection of the energy-taking capacitor is illustrated:

[0066] 1. Select two cases of built-in and external pole of energy-taking capacitor, and obtain the three-dimensional simplified model of the internal pole of the pole-mounted circuit breaker respectively;

[0067] Reference Figure 2 The model of the built-in pole of the energy-taking capacitor includes the laminated sampling capacitor, the wound energy-taking capacitor, the coil wire package of the current transformer, the conductive rod on the outgoing line side of the pole of the pole-mounted circuit breaker, and the grounding rod;

[0068] When the energy-taking capacitor is external to the pole, there is enough electrical insulation distance between the energy-taking capacitor and the pole, and the energy-taking capacitor has an independent insulation structure under the external condition of the energy-taking capacitor, and there is a composite insulation of epoxy resin and silicone rubber between the energy-taking capacitor and the internal elements of the pole. Therefore, it can be considered that it will not affect the internal pole. This embodiment directly uses the simulation model without energy-taking capacitor, and reference Figure 3 The model of the external pole of the energy-taking capacitor includes the laminated sampling capacitor, the coil wire package of the current transformer, the conductive rod on the outgoing line side of the pole of the pole-mounted circuit breaker, and the grounding rod;

[0069] The finite element simulation models of the two models are constructed in the AC / DC module of COMSOL Multiphysics respectively;

[0070] 2. The research type is set as steady-state research, focusing on the materials of each component and electrostatic boundary conditions. The conductive rod of the pole is at a high potential. Considering the limiting case of the model simulation calculation, the limiting voltage value is used. The current transformer coil and grounding rod are set to zero potential. The sampling capacitor and energy extraction capacitor are arranged from top to bottom according to the number of capacitor models. The limiting voltage value is assigned proportionally.

[0071] The electrostatic field was solved using the COMSOL Multiphysics 5.5 AC / DC module. Limiting ideal values ​​were assigned, and the steady-state Maxwell's equations were used as the theoretical calculation formula. The model was decomposed into finite element units and simulations were performed. The electric field distribution of the sampling capacitor and the energy harvesting capacitor, as well as the electric field distribution between them, was the main research object. The simulation results were obtained. The steady-state Maxwell's equations can be:

[0072]

[0073] in, The operator represents vectors; H represents magnetic field strength. Let represent displacement current density, J represent conduction current density, E represent electric field strength, D represent electric flux density, ρ represent charge density, and B represent magnetic induction intensity.

[0074] 3. Reference Figures 4-5 Using the ab and cd sections, the electric field of the cross section is plotted in the simulation results. The electric field distribution of the model cross section is analyzed. The electric field distribution map of the cross section shows the electric field distortion points and the electric field concentration locations, i.e. the locations with larger electric field strength values, according to the legend of the electric field value and the color table.

[0075] Based on the maximum electric field strength, it can be concluded that compared to an externally mounted energy harvesting capacitor, the internally mounted energy harvesting capacitor has more distortion points in its electric field distribution due to the shorter electrical distance between it and the sampling capacitor. This distortion is mainly manifested in the following ways:

[0076] (1) Around the top and bottom portions of the sampling capacitor on the left side;

[0077] (2) The top and bottom capacitors on the right side of the sampling capacitor;

[0078] (3) Both sides of the energy harvesting capacitor and the connection points between the components of the energy harvesting capacitor.

[0079] 4. According to Gauss's law, a conductor in electrostatic equilibrium is an equipotential body, and its surface is an equipotential surface. Charge can only be distributed on the surface, and the surface charge density at each point on the surface is proportional to the magnitude of the electric field strength at the immediate vicinity of the surface, i.e., the magnitude of the potential gradient. Areas with greater surface curvature have a larger potential gradient and a stronger electric field.

[0080] Based on the simulated electric field distribution of the cross-section, it can be seen from the numerical electric field graph that the electric field distortion is most severe at the corners of the sampling capacitor. This is consistent with the characteristic of electric field concentration at the tips or burrs of components in high-voltage applications. Therefore, a three-dimensional cross-section is constructed at the location of electric field concentration, i.e., a three-dimensional cross-section is established at the four corners of the sampling capacitor, referring to... Figure 6 A three-dimensional cross section is constructed to determine the specific electric field distribution at locations of electric field concentration. The simulation software calibrates the position of the three-dimensional cross section; the number of calibration points can be controlled. The software extracts parameters from the horizontal and vertical coordinates of the calibration points and the corresponding electric field intensity, forming multiple data sets composed of (horizontal coordinate, vertical coordinate, and electric field intensity value). Based on the data in the array, the electric field distribution along the longitudinal physical distance of the model's surrounding spatial location is plotted. Figure 2 and Figure 3 The electric field at the longitudinal physical distances corresponding to positions a, b, c, and d in the diagram. Physical distance refers to the shortest line length between two points in space.

[0081] 5. Reference Figures 7-10 Based on the results of cross-sectional electric field analysis and three-dimensional cross-sectional analysis, the advantages and disadvantages of the two design methods are evaluated and compared.

[0082] For positions a and c, at the edge of the sampling capacitor, the electric field strength of the built-in model of the energy harvesting capacitor is significantly greater than that of the external model, and this increases with the vertical physical position.

[0083] For position b, at the edge of the sampling capacitor, the electric field strength of the built-in model of the energy harvesting capacitor is less than that of the external model, but the difference between the two is not significant; while near the top capacitor of the sampling capacitor, the electric field strength of the built-in model of the energy harvesting capacitor is greater than that of the external model.

[0084] For position d, the electric field strength of the built-in model of the sampling capacitor is smaller than that of the external model, but the difference in value is also small. Near the top capacitor of the sampling capacitor, the electric field strength of the two is relatively close.

[0085] In summary, based on the above simulations, the following conclusions can be drawn:

[0086] (1) In terms of the tangential electric field, the built-in model of the energy harvesting capacitor has more electric field distortion points under the same applied voltage compared with the external model. The maximum field strength of the corresponding tangential electric field distribution is also larger. Therefore, under long-term operation, the built-in design of the energy harvesting capacitor has greater risks in terms of insulation design.

[0087] (2) The sampling capacitor and the energy harvesting capacitor are electrically close in the built-in design, so the two will have an electric field interaction, which may have a certain impact on the accuracy and lifespan of the two types of capacitors.

[0088] (3) When the energy-taking capacitor is external, the electric field distribution of the surrounding space at the edge of the sampling capacitor is obviously better than that of the internal design,

[0089] and the maximum field strength at the edge of the sampling capacitor is also smaller.

[0090] Therefore, in terms of maintaining the uniform distribution of the internal space electric field of the pole and optimizing the design, the design of the external energy-taking capacitor has obvious advantages in the uniform distribution of the electric field compared with the design of the internal energy-taking capacitor in the pole.

[0091] Embodiment three

[0092] On the basis of the above-mentioned embodiments, the method further comprises:

[0093] obtaining the running state parameters and the second electric field distribution data of the pole of the pole-mounted circuit breaker, fusing the running state parameters and the second electric field distribution data to obtain fusion data;

[0094] constructing a four-dimensional electric field model of the pole based on the fusion data and the finite element simulation model;

[0095] obtaining an optimal position based on the four-dimensional electric field model; in this embodiment, the optimal position can be obtained by using existing algorithms (such as starting a quantum genetic algorithm for multi-objective optimization, generating a Pareto frontier solution set, and selecting an optimal solution to obtain the optimal position) and a historical electric field data training model to find the optimal position.

[0096] obtaining an adjustment amount based on the optimal position, such as obtaining an adjustment amount according to the initial position and the optimal position of the energy-taking capacitor;

[0097] adjusting the position of the capacitor based on the adjustment amount to adjust the internal space electric field distribution of the pole.

[0098] In this embodiment, the running state parameters and the second electric field distribution data are obtained based on a multi-modal sensor, and the running state parameters include temperature, mechanical stress, and load current.

[0099] The multi-modal sensor comprises an electric field sensor, a temperature sensor, and a strain gauge, the electric field sensor is used to collect the spatial electric field distribution, the temperature sensor is used to collect the temperature, and the strain gauge is used to collect the mechanical stress.

[0100] The electric field sensor is spirally distributed on the internal surface of the pole, the temperature sensor is internally built in the pole, and the strain gauge is installed on the fixing device of the energy-taking capacitor.

[0101] In this embodiment, the electric field sensor can be a graphene film electric field sensor, the temperature sensor can be a fiber Bragg grating temperature sensor, and the strain gauge can be a MEMS micro-strain gauge.

[0102] In the embodiment, a material database is constructed, the material database includes a plurality of materials, each material corresponds to a Poisson's ratio, an elastic modulus and a thermal expansion coefficient at different temperatures;

[0103] A strain and a deformation are obtained based on the temperature, the mechanical stress and the material database, the four-dimensional electric field model is updated based on the strain and the deformation, and the adjustment amount is obtained based on the updated four-dimensional electric field model; the deformation degree of the material is obtained according to the strain and the deformation, the three-dimensional coordinates inside the pole are updated in real time, and the four-dimensional electric field model is updated.

[0104] The calculation formula of the strain is:

[0105]

[0106] The calculation formula of the deformation is:

[0107] L = a L0 Delta T;

[0108] Wherein, sigma represents the mechanical stress, E represents the elastic modulus, v represents the Poisson's ratio, epsilon represents the strain tensor, k represents the volume strain, alpha represents the thermal expansion coefficient, delta represents the unit tensor, L represents the deformation, and L0 represents the initial length.

[0109] In the embodiment, based on the adjustment amount, the position of the capacitor is adjusted by an adjusting device, the adjusting device includes a base, a piezoelectric ceramic and a moving platform, the piezoelectric ceramic is installed on the base, the top of the piezoelectric ceramic is connected with the bottom of the moving platform, and the capacitor is installed on the moving platform.

[0110] Based on the adjustment amount, a driving voltage is obtained, the driving voltage is input to the piezoelectric ceramic, the piezoelectric ceramic generates displacement along the axial direction, pushes the moving platform, and adjusts the position of the capacitor to the optimal position.

[0111] In the embodiment, the piezoelectric ceramic can be stacked piezoelectric actuators or composed of a plurality of PZT pieces in series, so as to realize large displacement output. The piezoelectric ceramic is connected with the circuit of the pole-mounted circuit breaker, so as to input the driving voltage to the piezoelectric ceramic.

[0112] The piezoelectric ceramic material (such as PZT-8) directly generates mechanical deformation under the action of voltage, the displacement resolution can reach 0.1 nm, the response time is in the microsecond level, meets the real-time dynamic adjustment demand, and its high stiffness can withstand the electromagnetic force impact under the high voltage electric field, avoids displacement drift, has strong anti-interference ability, and ensures the stability in the extreme environment; and the piezoelectric ceramic stack is driven by material deformation, has no mechanical contact components, and greatly improves the service life.

[0113] The calculation formula for obtaining the driving voltage is:

[0114] ΔL = d 33 · V · n;

[0115] Wherein, ΔL represents the adjustment amount, d 33 represents the piezoelectric strain constant, V represents the driving voltage, and n represents the number of piezoelectric ceramic sheets

[0116] In the embodiment, the piezoelectric ceramic top and the motion platform bottom are connected through a stress concentration mechanism, the base and the motion platform are connected through a guide mechanism, such as the connection between the bottom of the motion platform and the top of the base, and the piezoelectric ceramic and the base are connected through a pre-tightening force adjustment module.

[0117] The stress concentration mechanism can be elastomeric pads, which disperse the contact stress through the compression deformation of the elastic material (such as silicone rubber) to avoid local stress concentration. In the embodiment, a hemispherical ceramic pad is preferred, the circular plane of the hemispherical ceramic pad is connected with the bottom of the motion platform, and the arc top of the semicircular surface is fixedly connected with the center point of the piezoelectric ceramic. The hemispherical ceramic pad reduces the contact stress concentration while reducing the friction and assembly error through spherical contact, improves the displacement transmission efficiency, and the thermal expansion coefficient of the ceramic material is low, reducing the influence of temperature change on the contact interface.

[0118] The guide mechanism can be a leaf spring flexure (which realizes single-degree-of-freedom guiding by bending deformation of an elastic sheet) or a flexible hinge, and is preferably a double parallelogram flexure, which is symmetrically distributed to offset non-axial forces, can provide high-precision guiding while allowing a small displacement, and avoids friction and wear.

[0119] The pre-tightening force adjustment module can be an elastic element, such as a spring, and is preferably a disc spring. The spring stiffness coefficient matches the output characteristics of the piezoelectric ceramic, and the spring can be compressed by an adjusting screw, and the pressure is applied to the platform by the adjusting screw to ensure that the piezoelectric stack is always in a compressed state.

[0120] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, it is intended that the appended claims include all such modifications and variations as fall within the scope of the present application.

[0121] It is apparent that those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. It is therefore intended that the present application cover all such changes and modifications that are within its scope.

Claims

1. A method for analyzing the spatial electric field of an internally and externally mounted energy-harvesting capacitor in a pole-mounted circuit breaker, characterized in that, The method includes: A finite element simulation model is constructed based on the structure and simulation equipment of the pole-mounted circuit breaker. The first electric field distribution data and the position of the target element are obtained based on the finite element simulation model. Based on the position, the first electric field distribution data, the material data of the pole-mounted circuit breaker, and the boundary conditions of the electrostatic field, the first sectional electric field is plotted. The electric field concentration position and electric field distortion point are obtained based on the first electric field intensity of the sectional electric field. A three-dimensional cross section is constructed based on the electric field concentration position and the electric field distortion point. The electric field is analyzed based on the three-dimensional cross section to obtain the analysis results. The specific steps for obtaining the analysis results based on the three-dimensional cross-section analysis of the electric field include: The second electric field intensity of the three-dimensional cross-section is obtained, and a longitudinal cross-sectional electric field is constructed based on the second electric field intensity and a preset distance. The electric field distribution law is analyzed based on the longitudinal cross-sectional electric field and the first cross-sectional electric field to obtain the analysis result. The specific steps for obtaining the first electric field distribution data based on the finite element simulation model include: The number of the target components is obtained, the voltage value of the target components is set based on the number and a preset limit voltage value, and the first electric field distribution data is obtained based on the voltage value.

2. The spatial electric field analysis method for a pole-mounted circuit breaker with internal and external energy harvesting capacitors as described in claim 1, characterized in that, The preset limit voltage value is kV.

3. The spatial electric field analysis method for a pole-mounted circuit breaker with internal and external energy harvesting capacitors as described in claim 1, characterized in that, The method further includes: The operating status parameters and second electric field distribution data of the pole-mounted circuit breaker pole are obtained, and the operating status parameters and the second electric field distribution data are fused to obtain fused data. Based on the fused data and the finite element simulation model, a four-dimensional electric field model of the pole is constructed. The optimal position is obtained based on the four-dimensional electric field model, the adjustment amount is obtained based on the optimal position, the position of the capacitor is adjusted based on the adjustment amount, and the electric field distribution inside the electrode is adjusted.

4. The spatial electric field analysis method for an internally and externally mounted energy harvesting capacitor in a pole-mounted circuit breaker according to claim 3, characterized in that, The operating state parameters and the second electric field distribution data are obtained based on multimodal sensors. The operating state parameters include temperature, mechanical stress, and load current. The multimodal sensor includes an electric field sensor, a temperature sensor, and a strain gauge. The electric field sensor is used to acquire the spatial electric field distribution, the temperature sensor is used to acquire the temperature, and the strain gauge is used to acquire the mechanical stress. The electric field sensor is spirally distributed on the inner surface of the electrode post, the temperature sensor is built into the electrode post, and the strain gauge is mounted on the fixing device of the energy harvesting capacitor.

5. A spatial electric field analysis method for a pole-mounted circuit breaker with internal and external energy harvesting capacitors according to claim 4, characterized in that, Construct a materials database, which includes several materials, each corresponding to Poisson's ratio, elastic modulus and coefficient of thermal expansion at different temperatures; Strain and deformation are obtained based on temperature, mechanical stress, and the material database; the four-dimensional electric field model is updated based on the strain and deformation; and the adjustment amount is obtained based on the updated four-dimensional electric field model. The formula for calculating the strain is as follows: ； in, Indicates mechanical stress. Indicates the elastic modulus. Represents Poisson's ratio. Represents the strain tensor. Indicates volumetric strain. Indicates the coefficient of thermal expansion. Indicates temperature change, Represents a unit tensor.

6. The spatial electric field analysis method for an internally and externally mounted energy harvesting capacitor in a pole-mounted circuit breaker according to claim 3, characterized in that, Based on the adjustment amount, the adjustment device adjusts the position of the capacitor. The adjustment device includes a base, a piezoelectric ceramic and a motion platform. The piezoelectric ceramic is mounted on the base, and the top of the piezoelectric ceramic is connected to the bottom of the motion platform. The capacitor is mounted on the motion platform. The driving voltage is obtained based on the adjustment amount, and the driving voltage is input to the piezoelectric ceramic. The piezoelectric ceramic is displaced along the axial direction, which pushes the motion platform and adjusts the position of the capacitor to the optimal position.

7. A spatial electric field analysis method for a pole-mounted circuit breaker with internal and external energy harvesting capacitors according to claim 6, characterized in that, The top of the piezoelectric ceramic is connected to the bottom of the motion platform through a stress concentration mechanism, the base and the motion platform are connected through a guide mechanism, and the piezoelectric ceramic and the base are connected through a preload adjustment module.

8. A spatial electric field analysis method for a pole-mounted circuit breaker with internal and external energy harvesting capacitors according to claim 7, characterized in that, The stress concentration mechanism is a hemispherical ceramic gasket, the guiding mechanism is a flexible hinge, and the preload adjustment module is a disc spring.

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