Capacitance parameter identification method and device of transformer simulation model, medium and equipment
By performing parallel and series equivalent calculations and finite element analysis in the transformer simulation model, the capacitance parameters are accurately determined, which solves the problem of insufficient accuracy of the traditional model and realizes high-precision simulation and design optimization.
Patent Information
- Application Number
- CN202510256531.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2025-07-22
AI Technical Summary
In the transformer winding simulation model, simplified calculation results in insufficient accuracy of capacitor parameters, which is difficult to meet the needs of high-precision simulation.
The equivalent dielectric constant between the oil channels, wire cakes and windings is determined through parallel and series equivalent calculations, and the longitudinal and ground capacitance parameters are accurately calculated in combination with the finite element method, taking into account the winding geometry and dielectric characteristics.
It significantly improves simulation accuracy and improves the reliability and accuracy of transformer electrical performance analysis and design optimization.
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Figure CN120354806A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of power system simulation, and in particular to a method, device, medium and equipment for identifying capacitance parameters of a transformer simulation model. Background Art
[0002] In the process of constructing a transformer winding simulation model, the primary task is to calculate electrical parameters such as capacitance in the equivalent network of the transformer winding. The accuracy of these parameters directly determines the reliability of the simulation results.
[0003] In order to simplify calculations and analysis, traditional winding equivalent parameter models greatly simplify the structure of winding discs, ignore the influence of mutual inductance between non-adjacent windings, and assume that the high-voltage and low-voltage windings in the same phase have the same number of discs or turns, only considering the coupling capacitance between the same positions of the high- and low-voltage windings. However, this simplified method can only reflect the approximate range of capacitance parameters, and it is difficult to meet the requirements of high-precision simulation due to the limitations of calculation accuracy. Summary of the Invention
[0004] Based on this, it is necessary to provide a method, device, medium and equipment for identifying capacitance parameters of a transformer simulation model to solve the problem that the existing technology is difficult to meet the requirements of high-precision simulation.
[0005] A method for identifying capacitance parameters of a transformer simulation model, the method comprising:
[0006] In the transformer simulation model, perform parallel equivalent calculation according to the first relative permittivity of the spacer and the second relative permittivity of the oil duct gap to obtain the first equivalent permittivity of the oil duct composite insulation, and perform series equivalent calculation according to the first equivalent permittivity and the third relative permittivity of the turn insulation layer to obtain the second equivalent permittivity of the insulation between discs;
[0007] Perform series equivalent calculation according to the second relative permittivity of the oil duct gap between windings, the third relative permittivity of the turn insulation layer and the fourth relative permittivity of the insulating cylinder to obtain the third equivalent permittivity of the composite insulation between windings;
[0008] Based on the second equivalent permittivity, calculate the longitudinal equivalent capacitance parameters under different preset winding methods; wherein, the preset winding methods include continuous winding, interwound winding and inner shield winding;
[0009] Calculate the coupling capacitance parameters between windings by the finite element method;
[0010] Calculate the capacitance parameters to ground based on the third equivalent permittivity.
[0011] In one embodiment, the calculation formula for the first equivalent permittivity is:
[0012]
[0013] In the above formula, ε ye is the first equivalent dielectric constant; ε y is the second relative dielectric constant; ε d is the first relative dielectric constant; n is the number of spacers; k is the width of a single spacer; r1 is the inner diameter of the winding disk; r2 is the outer diameter of the winding disk.
[0014] In one embodiment, the calculation formula for the second equivalent dielectric constant is:
[0015]
[0016] In the above formula, ε be is the second equivalent dielectric constant; ε ye is the first equivalent dielectric constant; ε b is the third relative dielectric constant; a be is the distance between the bare conductors of the winding disk; a ye is the height of the oil duct gap; a b is the thickness of the turn insulation layer.
[0017] In one embodiment, the calculation formula for the third equivalent dielectric constant is:
[0018]
[0019] In the above formula, ε re is the third equivalent dielectric constant; ε y is the second relative dielectric constant; ε b is the third relative dielectric constant; ε t is the fourth relative dielectric constant; a y is the thickness of the oil duct gap; a b is the thickness of the turn insulation layer; a t is the thickness of the insulating cylinder; d re is the average diameter of the composite insulation between windings; d y is the uniform diameter of the oil duct gap; d b is the uniform diameter of the turn insulation layer; d t is the diameter of the insulating cylinder.
[0020] In one embodiment, when the preset winding method is the continuous type, the calculation formula for the longitudinal equivalent capacitance parameter is:
[0021]
[0022] In the above formula, C zis the longitudinal equivalent capacitance parameter in the continuous winding method; C t is the inter-turn capacitance; C d is the capacitance between pancakes; 2N is the number of turns of a single pancake unit; ε0 is the vacuum permittivity; ε b is the third relative permittivity; ε be is the second equivalent permittivity; d a is the average radial diameter of the pancake; h is the axial height of a single turn of bare wire; B is the axial height of the pancake; a b is the thickness of the turn insulation layer; a be is the distance between the bare wires of the pancake;
[0023] When the preset winding method is the interlaced method, the calculation formula for the longitudinal equivalent capacitance parameter is:
[0024]
[0025] In the above formula, C s is the longitudinal equivalent capacitance parameter in the interlaced winding method;
[0026] When the preset winding method is the internal shielding method, the calculation formula for the longitudinal equivalent capacitance parameter is:
[0027]
[0028] In the above formula, C m is the longitudinal equivalent capacitance parameter in the internal shielding winding method; b1 is the total thickness of the wire turns; b2 is the total thickness of the shielding layer wire turns.
[0029] In one embodiment, calculating the coupling capacitance parameter between windings by the finite element method includes:
[0030] In a three-dimensional electrostatic field, calculating the electric field strength and electric flux density of the winding based on Maxwell's equations, and solving the capacitive stored energy between each node by the finite element method, expressed as:
[0031]
[0032] In the above formula, W e is the capacitive stored energy; D is the electric flux density; E is the electric field strength;
[0033] Calculating the capacitance parameter between nodes and the self-capacitance of nodes according to the stored energy, expressed as:
[0034]
[0035]
[0036] In the above formula, C iiis the self-capacitance of node i; W iu C ii Stored energy; V i is the voltage value of node i; C ij is the coupling capacitance between node i and node j; W ij C ij Stored energy; V j is the voltage value of node j; C jj is the self-capacitance of node j;
[0037] Fill all calculated capacitance values into the capacitance matrix; wherein the capacitance matrix is an n×n symmetric matrix, where C ii are diagonal elements, C ij are non-diagonal elements.
[0038] In one embodiment, the third equivalent dielectric constant includes the equivalent dielectric constant between the high-voltage side winding and the oil tank wall and the equivalent dielectric constant between the low-voltage side and the iron core, the ground capacitance parameter includes the coupling capacitance between the high-voltage side winding and the oil tank wall and the coupling capacitance between the low-voltage side and the iron core, and the ground capacitance parameter is calculated based on the third equivalent dielectric constant, expressed as:
[0039]
[0040] In the above formula, C HVg is the coupling capacitance between the high voltage side winding and the tank wall; C LVg is the coupling capacitance between the low voltage side and the iron core; k is the correction coefficient; ε HVg is the equivalent dielectric constant between the high-voltage side winding and the tank wall; ε LVg is the equivalent dielectric constant between the low-voltage side and the iron core; ε0 is the dielectric constant of vacuum; l HV is the axial height of the high-voltage side winding coil; l LV is the axial height of the low-voltage side winding coil; R y R is the distance between the center of the high-voltage side winding and the inner wall of the oil tank; HV-w is the outer radius of the high voltage side winding; R LV-n is the inner radius of the low voltage side winding; R x is the core radius.
[0041] A capacitance parameter identification device for a transformer simulation model, the capacitance parameter identification device for the transformer simulation model comprising:
[0042] A relative permittivity calculation module, configured to perform parallel equivalent calculation in the transformer simulation model according to the first relative permittivity of the spacer and the second relative permittivity of the oil duct gap, so as to obtain the first equivalent relative permittivity of the oil duct composite insulation, and perform series equivalent calculation according to the first equivalent relative permittivity and the third relative permittivity of the turn insulation layer, so as to obtain the second equivalent relative permittivity of the insulation between disk coils; and perform series equivalent calculation according to the second relative permittivity of the oil duct gap between windings, the third relative permittivity of the turn insulation layer, and the fourth relative permittivity of the insulating cylinder, so as to obtain the third equivalent relative permittivity of the insulation between windings;
[0043] A capacitance parameter identification module, configured to calculate the longitudinal equivalent capacitance parameters under different preset winding modes respectively based on the second equivalent relative permittivity; wherein, the preset winding modes include continuous winding, interwound winding and inner shield winding; and calculate the coupling capacitance parameters between windings by the finite element method; and calculate the capacitance parameters to ground based on the third equivalent relative permittivity.
[0044] A computer-readable storage medium stores a computer program, which when executed by a processor, causes the processor to execute the steps of the capacitance parameter identification method of the above-mentioned transformer simulation model.
[0045] A terminal device includes a memory and a processor, the memory stores a computer program, which when executed by the processor, causes the processor to execute the steps of the capacitance parameter identification method of the above-mentioned transformer simulation model.
[0046] The present invention provides a capacitance parameter identification method, device, medium and equipment for a transformer simulation model. First, by parallel and series equivalent calculations, the equivalent relative permittivities of the oil duct composite insulation, the insulation between disk coils and the insulation between windings are accurately determined, and then the longitudinal equivalent capacitance parameters under different winding modes are calculated. Next, the coupling capacitance between windings is accurately solved by the finite element method, and the capacitance parameters to ground are obtained by calculation based on the third equivalent relative permittivity. This method can comprehensively consider various influencing factors, such as the geometric shape, dielectric characteristics and shielding effect of the windings. Compared with the traditional simplified model, the simulation accuracy is significantly improved, the demand for high-precision simulation is met, and the reliability and accuracy of the electrical performance analysis and design optimization of the transformer are improved. Description of the Drawings
[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0048] Among them:
[0049] Figure 1 It is a schematic flow chart of the capacitance parameter identification method for the transformer simulation model;
[0050] Figure 2 It is a schematic diagram of the composite insulation between the coil disks;
[0051] Figure 3 It is a schematic diagram of the composite insulation between the windings;
[0052] Figure 4a It is a schematic diagram of the continuous type turn structure;
[0053] Figure 4b It is for Figure 4a the schematic diagram of the potential distribution;
[0054] Figure 5a It is a schematic diagram of the interlaced type turn structure;
[0055] Figure 5b It is for Figure 5a the schematic diagram of the potential distribution;
[0056] Figure 6a It is a schematic diagram of the inner shielded type turn structure;
[0057] Figure 6b It is for Figure 6a the schematic diagram of the potential distribution;
[0058] Figure 7 It is a schematic diagram of the structure of the capacitance parameter identification device for the transformer simulation model;
[0059] Figure 8 It is a structural block diagram of the terminal device. Specific embodiments
[0060] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.
[0061] The terms "first", "second", etc. in the description, claims and the above-mentioned drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.
[0062] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appearing at various positions in the description does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.
[0063] As Figure 1 shown, Figure 1 As a schematic flow chart of the capacitance parameter identification method for the transformer simulation model in an embodiment, the steps provided by the capacitance parameter identification method for the transformer simulation model in this embodiment include:
[0064] S101, in the transformer simulation model, perform parallel equivalent calculation according to the first relative permittivity of the spacer and the second relative permittivity of the oil duct gap to obtain the first equivalent permittivity of the oil duct composite insulation, and perform series equivalent calculation according to the first equivalent permittivity and the third relative permittivity of the turn insulation layer to obtain the second equivalent permittivity of the insulation between the winding disks.
[0065] It can be understood that the inside of the transformer box is composed of various insulating materials, such as the turn insulation layer of the winding, the external insulation layer and spacers of the winding disk, the insulating cylinder between the windings, the insulating oil in the box, etc. The electrical characteristics of these insulating materials are characterized by their relative permittivities. From the flat capacitor calculation formula:
[0066]
[0067] it can be seen that the insulating medium in the winding composition can be indirectly equivalent to the capacitance parameter in the circuit model, and solving the relative permittivity of the insulating medium is the basis for calculating the capacitance parameter. Among them, the relative permittivity of the transformer simulation model is mainly composed of two parts: the equivalent relative permittivity of the insulation between the winding disks and the equivalent relative permittivity of the insulation between the windings. This step calculates the equivalent relative permittivity of the insulation between the winding disks.
[0068] On this basis, as Figure 2As shown in the figure, considering the parallel structure of the spacer insulation and the oil duct clearance insulation, the parallel structure indicates that the two insulating media will jointly affect the capacitance under the action of the electric field. Therefore, the dielectric constants of the two are calculated by parallel equivalent. In this way, the first equivalent dielectric constant of the oil duct composite insulation, that is, the equivalent electrical characteristics of the composite insulation composed of the spacer and the oil duct, is obtained.
[0069] Furthermore, considering the series structure of the turn insulation layer and the oil duct composite insulation, the series structure means that the two parts of insulating materials alternate with each other, and the electric field and charge of each part act on one of the parts respectively. Therefore, by calculating the series of the first equivalent dielectric constant of the oil duct composite insulation and the third relative dielectric constant of the turn insulation layer, the second equivalent dielectric constant of the composite insulation between the pancakes is obtained.
[0070] S102, perform a series equivalent calculation according to the second relative dielectric constant of the oil duct clearance between windings, the third relative dielectric constant of the turn insulation layer, and the fourth relative dielectric constant of the insulating cylinder, so as to obtain the third equivalent dielectric constant of the composite insulation between windings.
[0071] As Figure 3 shown, in this embodiment, the composite insulation between windings is divided into the following parts: the insulation between the high and low windings, which is located between the high-voltage and low-voltage windings of the transformer. The insulation between the high-voltage winding and the tank wall, which is located between the high-voltage winding and the transformer shell (tank wall). The insulation between the low-voltage winding and the iron core, which is located between the low-voltage winding and the iron core. The insulating media of these three are all composed of the turn insulation layer, the insulating cylinder, and the oil duct clearance. And because these insulating materials are arranged in sequence physically, their capacitance characteristics are in series and can be calculated by series equivalent to obtain the third equivalent dielectric constant of the composite insulation between windings.
[0072] S103, calculate the longitudinal equivalent capacitance parameters under different preset winding methods based on the second equivalent dielectric constant.
[0073] Among them, the longitudinal equivalent capacitance refers to the capacitance between the turns inside the winding and the capacitance between adjacent pancakes. However, the inter-turn capacitance and the inter-pancake capacitance are distributed structures, and different winding methods have a great influence on the calculation of capacitance parameters. The preset winding methods include the interlaced type, the inner shield type, the continuous type, the segmented type, the concentric type, etc.
[0074] Optionally, for different preset winding methods, the longitudinal equivalent capacitance can be calculated based on the second equivalent dielectric constant by the energy equivalence method. In the energy equivalence method, the electric field energy of the winding is mainly calculated, and this energy is equivalent to the capacitance on a certain part of the winding (such as a single pancake or multiple pancakes), so as to obtain the longitudinal equivalent capacitance parameters. This method takes into account the distribution of the electric field and the capacitance in the winding and can more accurately reflect the actual capacitance characteristics of the winding.
[0075] S104, calculate the coupling capacitance parameters between windings by the finite element method.
[0076] In this step, calculating the coupling capacitance parameters between windings by the finite element method is actually to perform three-dimensional simulation on the windings through tools such as ANSYS Maxwell, and accurately calculate the influence of capacitance coupling between each turn cake of the windings (including misaligned turn cakes). This method can overcome the limitations of traditional calculation methods when dealing with complex winding structures, provide more accurate coupling capacitance parameters, and provide important electrical characteristic data for the design and optimization of transformers.
[0077] S105, calculate the capacitance parameters to ground based on the third equivalent relative permittivity.
[0078] Since the middle winding of the three-winding transformer is protected by multiple insulating layers and the shielding structures of the high-voltage side and low-voltage side windings, the coupling relationship between the middle winding and the iron core and the tank is usually ignored in the circuit model. Therefore, the calculation of the capacitance to ground in this embodiment only focuses on the capacitance between the high-voltage side winding and the tank wall and the capacitance between the low-voltage side winding and the iron core.
[0079] We use the third equivalent relative permittivity to describe the electric field distribution between the winding and the grounded part (such as the tank, the iron core). Then, apply an appropriate capacitance calculation formula (such as the parallel plate capacitance formula) or perform electric field simulation by the finite element method to calculate the coupling capacitance between the high-voltage side winding and the tank wall, and the coupling capacitance between the low-voltage side winding and the iron core.
[0080] The capacitance parameter identification method of the above transformer simulation model first accurately determines the equivalent relative permittivity of the oil duct composite insulation, the turn cake-to-turn cake composite insulation, and the winding-to-winding composite insulation through parallel and series equivalent calculations, and then calculates the longitudinal equivalent capacitance parameters under different winding methods. Then, use the finite element method to accurately solve the coupling capacitance between windings, and obtain the capacitance parameters to ground through the calculation based on the third equivalent relative permittivity. This method can comprehensively consider various influencing factors, such as the geometric shape, dielectric characteristics, and shielding effect of the windings. Compared with the traditional simplified model, it significantly improves the simulation accuracy, meets the requirements for high-precision simulation, and improves the reliability and accuracy of the electrical performance analysis and design optimization of transformers.
[0081] Optionally, the calculation formula for the first equivalent relative permittivity in S101 is:
[0082]
[0083] In the above formula, ε ye is the first equivalent relative permittivity; ε y is the second relative permittivity; ε dis the first relative permittivity; n is the number of spacers; k is the width of a single spacer; r1 is the inner diameter of the winding disc; r2 is the outer diameter of the winding disc.
[0084] This is because according to the parallel plate capacitor formula, the calculation of capacitance involves the area of the electrodes. In the oil duct composite insulation structure, the area distribution of the spacer and the oil duct gap is as follows:
[0085] S y = S ye - S d
[0086] S d = nBk
[0087] S ye = πB(r1 + r2) / 2
[0088] Among them, S ye is the total area of the oil duct composite insulation; S y is the area of the oil duct gap; S d is the area of the spacer; B is the width of the winding disc.
[0089] On this basis, the equivalent permittivity of the parallel capacitors follows the following formula:
[0090] ε ye S ye = ε y S y + ε d S d
[0091] Substitute the above expressions of S y for S d and after further simplification, we can get:
[0092]
[0093] Through the above formula, the equivalent permittivity of the oil duct composite insulation can be accurately calculated, providing a reliable basis for subsequent calculations of the composite insulation between winding discs and other capacitance parameters (such as longitudinal equivalent capacitance, capacitance to ground, etc.).
[0094] Optionally, the calculation formula for the second equivalent permittivity in S101 is:
[0095]
[0096] In the above formula, ε be is the second equivalent permittivity; ε ye is the first equivalent permittivity; ε b is the third relative permittivity; a be is the distance between the bare conductors of the winding disc; a yeis the height of the oil duct clearance; a b is the thickness of the turn insulation layer.
[0097] This is because for a series-distributed insulation structure, the reciprocal of its equivalent dielectric constant is equal to the sum of the reciprocals of the dielectric constants of each layer of insulation. Therefore, it satisfies:
[0098]
[0099] By transforming the above formula, we can obtain:
[0100]
[0101] Compared with the prior art, this method fully considers the series-distribution characteristics of the insulation material, combines detailed geometric parameters and dielectric constant calculations, and significantly improves the accuracy of the simulation model.
[0102] Optionally, the calculation formula for the third equivalent dielectric constant in S102 is:
[0103]
[0104] In the above formula, ε re is the third equivalent dielectric constant; εy is the second relative dielectric constant; εb is the third relative dielectric constant; εt is the fourth relative dielectric constant; a y is the thickness of the oil duct clearance; a b is the thickness of the turn insulation layer; a t is the thickness of the insulating cylinder; dr e is the average diameter of the composite insulation between windings; d y is the uniform diameter of the oil duct clearance; db is the uniform diameter of the turn insulation layer; dt is the diameter of the insulating cylinder.
[0105] This is because according to the calculation principle of series-distributed capacitance, the equivalent capacitance of the composite insulation between windings is composed of the series connection of the insulation capacitances of each part:
[0106]
[0107] And the flat-plate capacitance calculation formula is:
[0108]
[0109] It can be seen that the capacitance of each part of the insulation is related to its thickness a i , relative dielectric constant εi and path diameter d i . By synthesizing the parameters of each part, the equivalent dielectric constant of the composite insulation between windings is finally:
[0110]
[0111] This formula precisely considers the thickness, diameter, and dielectric property distribution of different materials for the multi-layer structure characteristics of the composite insulation between windings, significantly improving the accuracy of dielectric constant calculation.
[0112] In an example of a transformer simulation model, by calculating and summarizing the equivalent dielectric constants involved in S101 and S102, the following Table 1 can be obtained:
[0113] Insulating medium Equivalent dielectric constant Insulating medium Equivalent dielectric constant Insulating oil 2.2 High-voltage winding and medium-voltage winding 2.75 Insulating cylinder 3.3 Between medium-voltage winding discs 2.66 Spacer 3.3 Medium-voltage winding and low-voltage winding 2.86 High-voltage winding and oil tank 2.2 Between low-voltage winding discs 2.62 Between high-voltage winding discs 2.61 Low-voltage winding and iron core 2.87
[0114] Table 0
[0115] Optionally, the preset winding method in S103 is set to the interlaced type, the inner shield type, or the continuous type. If taking a double-winding cake of the winding as a winding cake unit and the number of turns of a single winding cake unit is 2N, applying the voltage U N to the winding cake unit, with the voltage evenly distributed on the conductor, the voltage drop between the turns of adjacent winding cakes is U N / 2N.
[0116] When the preset winding method is the continuous type, as Figure 4a and Figure 4b shown, Figure 4a is the schematic diagram of the continuous turn structure, Figure 4b is Figure 4a the schematic diagram of the potential distribution. The turns of the winding wound in the continuous type are arranged in sequence, and the capacitance between turns is relatively simple.
[0117] The electrostatic energy between turns is as shown in the following formula:
[0118]
[0119] In the above formula, d a is the average radial diameter of the winding cake, and h is the axial height of a single turn of bare wire.
[0120] The total energy between turns of the winding cake unit is as shown in the following formula:
[0121]
[0122] The total energy between cakes of a single winding cake can be determined by the following formula:
[0123]
[0124] Using the principle of energy equivalence: The energy of a single winding cake unit is equivalent to the sum of the total energy between turns and the total energy between cakes, as shown in the following formula:
[0125]
[0126] In the above formula, E z is the energy possessed by a single winding cake unit, and C zis the longitudinal equivalent capacitance of a single coil unit.
[0127] Combining the above formula, the longitudinal equivalent capacitance parameters under the continuous compilation method can be derived as:
[0128]
[0129] When the preset compilation method is tangled, such as Figure 5a and Figure 5b As shown, Figure 5a This is a schematic diagram of the tangled wire turn structure. Figure 5b for Figure 5a Schematic diagram of potential distribution. The tangled winding is characterized by staggered and tangled arrangement of cables. In this way, the potential difference between adjacent turns in a single coil is significantly increased compared to the continuous winding. The energy storage of the inter-turn capacitance increases according to the square relationship, resulting in the inter-turn capacitance being much larger than the inter-coil capacitance. Therefore, the influence of the inter-coil capacitance on the longitudinal equivalent capacitance is often ignored.
[0130] Among them, the potential difference between adjacent turns in a single coil is U N There are N-1 turn-to-turn capacitors of / 2, and the potential difference between the remaining N-1 turn-to-turn capacitors is (N-1)U N / N, according to the capacitor energy storage formula and the energy equivalence principle, it can be deduced that:
[0131]
[0132] In the above formula, C s It is the longitudinal equivalent capacitance parameter under the tangled compilation method.
[0133] When the preset compilation mode is internal shielding, such as Figure 6a and Figure 6b As shown, Figure 6a This is a schematic diagram of the inner shielded wire turn structure. Figure 6b for Figure 6a Schematic diagram of potential distribution. The unique shielding layer of the inner shielded winding makes the capacitance present a conical distribution and matches the gradient voltage distribution, but the shielding layer is generally not connected to the winding operating structure, and the longitudinal equivalent capacitance is smaller than that of the continuous winding.
[0134] Assuming that the number of turns in the shielding layer of the two-stage screen winding is n, the potential difference between adjacent turns in a single coil is U N There are n inter-turn capacitances of / 2, and the potential difference between adjacent turns is (N-1)U N There are n turn-to-turn capacitors of / 2N, and the potential difference of the remaining Nn-1 turn-to-turn capacitors is U N / 2N, according to the capacitor energy storage formula and the energy equivalence principle, it can be deduced that:
[0135]
[0136]
[0137] In the above formula, C m is the longitudinal equivalent capacitance parameter under the internal shielding winding method; b1 is the total thickness of the coil turns; b2 is the total thickness of the shielding layer coil turns.
[0138] Combined with the above dielectric constant solving process and the analysis method of the coil structure under different winding methods, the corresponding longitudinal equivalent capacitance is calculated. Taking the continuous winding as an example in this study, in an example of a transformer simulation model, Table 2 shows the calculation results of the longitudinal equivalent capacitance parameters of the continuous winding.
[0139] Winding type Longitudinal equivalent capacitance parameter value / pF HV winding 25 MV winding 30 LV winding 9
[0140] Table 2
[0141] Optionally, the specific steps for calculating the coupling capacitance parameters between windings in S104 by the finite element method are as follows:
[0142] A1. In the three-dimensional electrostatic field, calculate the electric field strength and electric flux density of the winding based on Maxwell's equations, and solve the capacitive stored energy between each node by the finite element method, expressed as:
[0143]
[0144] In the above formula, W e is the capacitive stored energy; D is the electric flux density; E is the electric field strength;
[0145] A2. Calculate the capacitance parameters between nodes and the self-capacitance of nodes according to the stored energy.
[0146] In this step, the energy equivalence method is used to inversely deduce the capacitance parameters of the nodes from the calculated energy values, expressed as:
[0147]
[0148] In the above formula, C ii is the self-capacitance of node i; W ii is the energy stored in C ii ; V i is the voltage value of node i; C ij is the coupling capacitance between node i and node j; W ij is the energy stored in C ij ; V j is the voltage value of node j; C jj is the self-capacitance of node j.
[0149] Through the above formulas, the coupling relationship can be established between different nodes, so as to accurately characterize the capacitive characteristics of the winding structure.
[0150] A3. Fill all calculated capacitance values into the capacitance matrix.
[0151] Among them, the capacitance matrix is a symmetric matrix of n×n, where C ii are diagonal elements, C ij are non-diagonal elements. The matrix is represented as:
[0152]
[0153] This matrix reflects the capacitance distribution of each node in the entire winding system and provides accurate capacitance parameter input for transformer simulation.
[0154] In an example of a transformer simulation model, the calculated inter-winding coupling capacitance parameters are shown in Table 3:
[0155] A-phase HV-MV capacitance Value (pF) B-phase MV-LV capacitance Value (pF) C(HV-1,MV-1) 4.7178 C(MV-1,LV-1) 2.1538 C(HV-1,MV-2) 0.3784 C(MV-1,LV-2) 0.7907 C(HV-1,MV-3) 0.0266 C(MV-1,LV-3) 0.1218 C(HV-8,MV-8) 2.4345 C(MV-8,LV-8) 1.2337 C(HV-8,MV-9) 0.6508 C(MV-8,LV-9) 0.6533 C(HV-8,MV-10) 0.0067 C(MV-8,LV-10) 0.1050 C(HV-16,MV-14) 0.1763 C(MV-16,LV-14) 0.0954 C(HV-16,MV-15) 1.7435 C(MV-16,LV-15) 0.6106 C(HV-16,MV-16) 5.4634 C(MV-16,LV-16) 1.7472
[0156] Table 3
[0157] Optionally, there are two methods for calculating the ground capacitance parameters in S105: the formula method and the finite element method. The formula method regards the winding as a coaxial cylindrical capacitor and uses Gauss's theorem to solve the calculation. HVg , the calculation formula is as follows:
[0158]
[0159] In the above formula, C HVg is the coupling capacitance between the high-voltage side winding and the tank wall; k is the correction coefficient; ε HVg is the equivalent dielectric constant between the high-voltage side winding and the tank wall; ε0 is the vacuum dielectric constant; l HV is the axial height of the high-voltage side winding coil; R y R is the distance between the center of the high-voltage side winding and the inner wall of the oil tank; HV-w is the outer radius of the high voltage side winding.
[0160] For the high-voltage side windings of phases A and C, since the area opposite to the tank wall accounts for three-quarters of the total area, and the remaining quarter of the area is shielded by multiple insulation layers, the capacitive coupling relationship with the adjacent phases and the tank wall is not considered, and k is generally taken as 3 / 4; for the high-voltage side winding of phase B, the area opposite to the tank wall accounts for one-half of the total area, and k is taken as 1 / 2.
[0161] For the coupling capacitance C between the low voltage side winding and the core LVg , the calculation formula is as follows:
[0162]
[0163] In the above formula, C LVg is the coupling capacitance between the low-voltage side and the iron core; ε LVg is the equivalent dielectric constant between the low-voltage side and the iron core; l LV is the axial height of the winding disk of the low-voltage side winding; R LV-n is the inner radius of the low-voltage side winding; R x is the radius of the core column. Here, the correction coefficient k takes the value of 1.
[0164] Taking phase A as an example, the capacitance parameter value of the capacitance to the ground calculated by the formula method is: C HVg = 1.68 pF, C LVg = 6.216 pF.
[0165] However, the coupling relationship between the winding disks at the head and tail ends of some actual transformer windings and the oil tank wall and the iron core column will change, that is: the coupling degree between the high-voltage side winding and the axially extended oil tank wall shows "large in the middle and small at both ends" with the change of the winding area, and the coupling degree between the winding disks at the head and tail ends and the radially extended oil tank wall is closer; the coupling degree between the low-voltage side winding and the iron core column will also show a similar change with the position of the winding disk, and the coupling capacitance value between the windings at the head and tail ends and the yoke is larger. At this time, the finite element method needs to be used to consider this deviation.
[0166] Table 4 shows some capacitance values to the ground solved by the finite element method, where CHVg 2 represents the coupling capacitance value between the second winding disk of the high-voltage side winding and the oil tank, CMVg 16 represents the coupling capacitance value between the 16th winding disk of the low-voltage side winding and the iron core, and the meanings of other parameters can be deduced similarly. In this paper, referring to the actual structure of the transformer, the capacitance to the ground is calculated and analyzed by combining the formula method and the finite element method.
[0167] A-phase capacitance to ground Value (pF) B-phase capacitance to ground Value (pF) CHVg2 1.1293 CHVg2 0.7295 CHVg9 0.8672 CHVg9 0.5445 CHVg16 2.6766 CHVg16 1.7989 CMVg2 4.8294 CMVg2 4.8531 CMVg9 4.7612 CMVg9 4.7708 CMVg16 7.7294 CMVg16 8.8208
[0168] Table 4
[0169] In one embodiment, as Figure 7 shown, a capacitance parameter identification device for a transformer simulation model is proposed, and the device includes:
[0170] The dielectric constant calculation module 701 is configured to perform parallel equivalent calculation in the transformer simulation model according to the first relative dielectric constant of the spacer and the second relative dielectric constant of the oil duct gap, so as to obtain the first equivalent dielectric constant of the oil duct composite insulation, and perform series equivalent calculation according to the first equivalent dielectric constant and the third relative dielectric constant of the turn insulation layer, so as to obtain the second equivalent dielectric constant of the composite insulation between the disk windings; and perform series equivalent calculation according to the second relative dielectric constant of the oil duct gap between windings, the third relative dielectric constant of the turn insulation layer, and the fourth relative dielectric constant of the insulating cylinder, so as to obtain the third equivalent dielectric constant of the composite insulation between windings.
[0171] The capacitance parameter identification module 702 is configured to calculate the longitudinal equivalent capacitance parameters under different preset winding modes respectively based on the second equivalent dielectric constant; wherein, the preset winding modes include continuous winding, interlaced winding, and internal shielding winding; and calculate the coupling capacitance parameters between windings by the finite element method; and calculate the capacitance parameters to ground based on the third equivalent dielectric constant.
[0172] Figure 8 The internal structure diagram of the terminal device in an embodiment is shown. As Figure 8 shown, the terminal device includes a processor, a memory, and a network interface connected through a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the terminal device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement the capacitance parameter identification method of the transformer simulation model. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute the capacitance parameter identification method of the transformer simulation model. Those skilled in the art can understand that Figure 8 the structure shown in is only a block diagram of some structures related to the solution of the present application, and does not constitute a limitation on the terminal device to which the solution of the present application is applied. The specific terminal device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.
[0173] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps are implemented: In a transformer simulation model, parallel equivalent calculation is performed according to the first relative permittivity of the spacer and the second relative permittivity of the oil duct gap to obtain the first equivalent permittivity of the oil duct composite insulation, and series equivalent calculation is performed according to the first equivalent permittivity and the third relative permittivity of the turn insulation layer to obtain the second equivalent permittivity of the composite insulation between the coil pancakes; Series equivalent calculation is performed according to the second relative permittivity of the oil duct gap between the windings, the third relative permittivity of the turn insulation layer, and the fourth relative permittivity of the insulating cylinder to obtain the third equivalent permittivity of the composite insulation between the windings; Longitudinal equivalent capacitance parameters under different preset winding methods are calculated based on the second equivalent permittivity; wherein, the preset winding methods include continuous winding, interwound winding, and inner shield winding; The coupling capacitance parameters between the windings are calculated by the finite element method; The capacitance parameters to the ground are calculated based on the third equivalent permittivity.
[0174] A terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following steps are implemented: In a transformer simulation model, parallel equivalent calculation is performed according to the first relative permittivity of the spacer and the second relative permittivity of the oil duct gap to obtain the first equivalent permittivity of the oil duct composite insulation, and series equivalent calculation is performed according to the first equivalent permittivity and the third relative permittivity of the turn insulation layer to obtain the second equivalent permittivity of the composite insulation between the coil pancakes; Series equivalent calculation is performed according to the second relative permittivity of the oil duct gap between the windings, the third relative permittivity of the turn insulation layer, and the fourth relative permittivity of the insulating cylinder to obtain the third equivalent permittivity of the composite insulation between the windings; Longitudinal equivalent capacitance parameters under different preset winding methods are calculated based on the second equivalent permittivity; wherein, the preset winding methods include continuous winding, interwound winding, and inner shield winding; The coupling capacitance parameters between the windings are calculated by the finite element method; The capacitance parameters to the ground are calculated based on the third equivalent permittivity.
[0175] It should be noted that the capacitance parameter identification method, device, equipment, and computer-readable storage medium of the above transformer simulation model belong to a general inventive concept, and the contents in the embodiments of the capacitance parameter identification method, device, equipment, and computer-readable storage medium of the transformer simulation model can be mutually applicable.
[0176] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. This program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above various methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in this application can include non-volatile and / or volatile memories. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.
[0177] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.
[0178] The above embodiments only represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of this application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of the patent of this application should be subject to the appended claims.
Claims
1. A method for identifying capacitance parameters of a transformer simulation model, characterized in that The method includes: In the transformer simulation model, parallel equivalent calculation is performed according to the first relative permittivity of the spacer and the second relative permittivity of the oil duct gap to obtain the first equivalent permittivity of the oil duct composite insulation, and series equivalent calculation is performed according to the first equivalent permittivity and the third relative permittivity of the turn insulation layer to obtain the second equivalent permittivity of the composite insulation between the disk windings; Series equivalent calculation is performed according to the second relative permittivity of the oil duct gap between the windings, the third relative permittivity of the turn insulation layer, and the fourth relative permittivity of the insulating cylinder to obtain the third equivalent permittivity of the composite insulation between the windings; Based on the second equivalent permittivity, the longitudinal equivalent capacitance parameters under different preset winding methods are calculated; wherein, the preset winding methods include continuous winding, interlaced winding, and inner shield winding; The coupling capacitance parameters between the windings are calculated by the finite element method; The capacitance parameters to ground are calculated based on the third equivalent permittivity.
2. The method according to claim 1, characterized in that, The calculation formula for the first equivalent permittivity is: In the above formula, ε ye is the first equivalent dielectric constant; ε y is the second relative dielectric constant; ε d is the first relative dielectric constant; n is the number of spacers; k is the width of a single spacer; r1 is the inner diameter of the winding disk; r2 is the outer diameter of the winding disk.
3. The method according to claim 1, wherein The calculation formula for the second equivalent permittivity is: In the above formula, ε be is the second equivalent dielectric constant; ε ye is the first equivalent dielectric constant; ε b is the third relative dielectric constant; a be is the distance between the bare conductors of the winding disk; a ye is the height of the oil duct clearance; a b is the thickness of the turn insulation layer.
4. The method according to claim 1, wherein The calculation formula for the third equivalent permittivity is: In the above formula, ε re is the third equivalent dielectric constant; ε y is the second relative dielectric constant; ε b is the third relative dielectric constant; ε t is the fourth relative dielectric constant; a y is the thickness of the oil duct clearance; a b is the thickness of the turn insulation layer; a t is the thickness of the insulating cylinder; d re is the average diameter of the composite insulation between windings; d y is the uniform diameter of the oil duct clearance; d b is the uniform diameter of the turn insulation layer; d t is the diameter of the insulating cylinder.
5. The method according to claim 1, wherein When the preset winding method is continuous winding, the calculation formula for the longitudinal equivalent capacitance parameters is: In the above formula, C z is the longitudinal equivalent capacitance parameter under the continuous winding method; C t is the inter-turn capacitance; C d is the capacitance between pancakes; 2N is the number of turns of a single pancake unit; ε0 is the vacuum permittivity; ε b is the third relative permittivity; ε be is the second equivalent permittivity; d a is the average radial diameter of the pancake; h is the axial height of a single turn of bare wire; B is the axial height of the pancake; a b is the thickness of the turn insulation layer; a be is the distance between the bare wires of the pancake; When the preset winding method is interlaced winding, the calculation formula for the longitudinal equivalent capacitance parameters is: In the above formula, C s is the longitudinal equivalent capacitance parameter under the intertwined winding method; When the preset winding method is inner shield winding, the calculation formula for the longitudinal equivalent capacitance parameters is: In the above formula, C m is the longitudinal equivalent capacitance parameter under the internal shielding winding method; b1 is the total thickness of the turns; b2 is the total thickness of the turns of the shielding layer.
6. The method according to claim 1, wherein The calculation of the coupling capacitance parameters between the windings by the finite element method includes: In the three-dimensional electrostatic field, the electric field strength and electric flux density of the windings are calculated based on Maxwell's equations, and the capacitive stored energy between each node is solved by the finite element method, expressed as: In the above formula, W e is the energy stored in the capacitor; D is the electric flux density; E is the electric field strength; According to the stored energy, the capacitance parameters between the nodes and the self-capacitance of the nodes are calculated, expressed as: In the above formula, C ii is the self-capacitance of node i; W ii is the energy stored in C ii ; V i is the voltage value of node i; C ij is the coupling capacitance between node i and node j; W ij is the energy stored in C ij ; V j is the voltage value of node j; C jj is the self-capacitance of node j; Fill all the calculated capacitance values into the capacitance matrix; wherein, the capacitance matrix is an n×n symmetric matrix, where C ii is the diagonal element and C ij is the non - diagonal element.
7. The method according to claim 1, wherein The third equivalent permittivity includes the equivalent permittivity between the high-voltage side winding and the tank wall and the equivalent permittivity between the low-voltage side and the iron core. The capacitance parameters to ground include the coupling capacitance between the high-voltage side winding and the tank wall and the coupling capacitance between the low-voltage side and the iron core. The calculation of the capacitance parameters to ground based on the third equivalent permittivity is expressed as: In the above formula, C HVg is the coupling capacitance between the high voltage side winding and the tank wall; C LVg is the coupling capacitance between the low voltage side and the iron core; k is the correction coefficient; ε HVg is the equivalent dielectric constant between the high-voltage side winding and the tank wall; ε LVg is the equivalent dielectric constant between the low-voltage side and the iron core; ε0 is the dielectric constant of vacuum; l HV is the axial height of the high-voltage side winding coil; l LV is the axial height of the low-voltage side winding coil; R y R is the distance between the center of the high-voltage side winding and the inner wall of the oil tank; HV-w is the outer radius of the high voltage side winding; R LV-n is the inner radius of the low voltage side winding; R x is the core radius.
8. A capacitance parameter identification device for a transformer simulation model, characterized in that, The capacitance parameter identification device of the transformer simulation model includes: A permittivity calculation module, configured to perform parallel equivalent calculation in the transformer simulation model according to the first relative permittivity of the spacer and the second relative permittivity of the oil duct gap to obtain the first equivalent permittivity of the oil duct composite insulation, and perform series equivalent calculation according to the first equivalent permittivity and the third relative permittivity of the turn insulation layer to obtain the second equivalent permittivity of the composite insulation between the disk windings; and perform series equivalent calculation according to the second relative permittivity of the oil duct gap between the windings, the third relative permittivity of the turn insulation layer, and the fourth relative permittivity of the insulating cylinder to obtain the third equivalent permittivity of the composite insulation between the windings; A capacitance parameter identification module is used to calculate the longitudinal equivalent capacitance parameters under different preset winding methods based on the second equivalent dielectric constant; wherein, the preset winding methods include continuous winding, interlaced winding, and inner shielded winding; and calculate the coupling capacitance parameters between windings through the finite element method; and calculate the capacitance parameters to the ground based on the third equivalent dielectric constant.
9. A computer-readable storage medium, characterized in that, A computer program is stored, and when the computer program is executed by a processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 7.
10. A terminal device, characterized in that, It includes a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 7.