Transformer high-frequency circuit equivalent model construction method and system for hfct current analysis

Abstract

The application provides a transformer high-frequency circuit equivalent model construction method and system for HFCT current analysis, belongs to the technical field of transformer partial discharge fault detection, and constructs a winding radial coupling parameter MPCLTL model; constructs a winding axial pie-to-pie coupling parameter LP model according to winding axial pie-to-pie electrical parameters; combines the MPCLTL model and the LP model to build a full-winding MPCLTL-LP model; performs high-frequency equivalent modeling on a core according to core structure parameters, material parameters and stacking coefficients to obtain a high-frequency equivalent model of the core; and combines the full-winding MPCLTL-LP model and the high-frequency equivalent model of the core to construct a coupling model between the full winding and the core. The application can accurately model the winding and the core inside the transformer according to the physical structure and characteristics of the winding and the core, adds a high-frequency pulse current signal to the winding side, detects a signal on a core grounding wire, and verifies the rationality of the high-frequency pulse current detection method.

Description

Technical Field

[0001] This invention relates to the field of transformer partial discharge fault detection technology, specifically to a method and system for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis. In particular, it refers to using an HFCT connected to the transformer grounding wire to detect the high-frequency pulse current generated when partial discharge occurs inside the transformer windings, and analyzing the principle of the high-frequency pulse current detection method by performing high-frequency modeling of the transformer. Background Technology

[0002] The traction rectifier dry-type transformer in subways plays a crucial role in converting electrical energy from high-voltage alternating current to the required direct current, supplying power to the traction system. However, with increasing service life, the transformer faces risks such as insulation deterioration and component loosening, leading to partial discharge and other faults, posing certain safety hazards.

[0003] Partial discharge is typically accompanied by phenomena such as heat, light, electromagnetic waves, and high-frequency pulse currents. Currently, commonly used methods for detecting partial discharge in transformers include electromagnetic wave methods, infrared thermography, ultrasonic methods, current methods, and transient voltage-to-ground methods. However, each method has its advantages and disadvantages. Electromagnetic wave and ultrasonic methods have low requirements for the internal structure of the transformer but are sensitive to environmental interference; infrared thermography allows for direct observation of the fault location but is significantly affected by ambient light; current methods can detect discharge signals relatively accurately but require transformer shutdown for maintenance; and transient voltage-to-ground methods can be performed while the transformer is in operation but require complex data processing and analysis. Therefore, high-frequency pulse current detection is often used in many scenarios due to its high sensitivity and strong anti-interference capabilities. The principle of high-frequency pulse current detection is to automatically acquire high-frequency pulse discharge signals and then connect a high-frequency pulse (HFCT) sensor to the transformer's grounding wire. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis, so as to solve at least one of the technical problems existing in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis, comprising:

[0007] Based on the loss parameters of each transmission line and combined with the actual line structure, a winding radial coupling parameter MPCLTL model is constructed.

[0008] Based on the electrical parameters between the axial discs of the windings, construct the LP model of the coupling parameters between the axial discs of the windings;

[0009] By combining the MPCLTL model and the LP model, a full-winding MPCLTL-LP model is constructed.

[0010] Based on the core structure parameters, material parameters, and stacking coefficient, a high-frequency equivalent model of the core is performed to obtain the high-frequency equivalent model of the core.

[0011] By combining the MPCLTL-LP model of the full winding and the high-frequency equivalent model of the iron core, a coupling model between the full winding and the iron core is constructed.

[0012] As a further limitation of the first aspect of the present invention, the loss parameters of each transmission line are segmented and connected in a lumped parameter manner, so that each transmission line becomes a lossless transmission line and a lumped resistor connected in series, thereby obtaining the MPCLTL model of each pancake; then all the single-pancake MPCLTL models are connected sequentially according to the actual structure to form the MPCLTL model of the full winding.

[0013] As a further limitation of the first aspect of the present invention, the LP model is a full winding axial coupling model constructed based on the axial inter-bill electrical parameters of the winding; since the axial dimension is much smaller than the wavelength of the high-frequency pulse current, the axial electrical parameters adopt lumped parameters.

[0014] As a further limitation of the first aspect of the present invention, a full winding MPCLTL-LP model is built in EMTP software; wherein, the following coupling method is adopted in the modeling process: only the coupling parameters between two directly opposite turns in adjacent cakes are considered; according to the coupling method, an axial LP model and an MPCLTL model of the transformer high-voltage winding are established in EMTP, and the mutual inductance between corresponding turns in the upper and lower cakes is ignored in both models.

[0015] As a further limitation of the first aspect of the present invention, the modeling of the iron core is as follows: the iron core can be regarded as a pure capacitor series-parallel circuit; wherein, the following simplifications are made: the influence of the oil passage inside the iron core is ignored, the insulation resistance and conductivity between the silicon steel sheets of the iron core are ignored, and the grounding wire of the iron core is led out from the middle stack of the iron core; according to the above simplification, the iron core column is divided into two semi-cylinders with completely equal left and right sides from the position where the grounding wire is led out; each semi-cylinder is further divided into several cuboids according to the multi-level circular structure of the iron core, and each cuboid contains several identical parallel plate capacitors; therefore, the equivalent total capacitance of each cuboid is calculated according to the iron core structural parameters, material parameters and stacking coefficient.

[0016] As a further definition of the first aspect of the present invention, the high-frequency signal is coupled to the iron core through the capacitance between the inner turn of the winding and the iron core, and finally flows into the ground through the iron core grounding line; according to the physical structure of the winding and the iron core, the innermost turn of each coil is divided into left and right half turns, and each half is coupled to the iron core through the equivalent capacitance between itself and the iron core; all coils of the entire winding are coupled to the iron core in this way, and the coupling model between the entire winding and the iron core can be constructed.

[0017] Secondly, the present invention provides a transformer high-frequency circuit equivalent model construction system for HFCT current analysis, comprising:

[0018] The first construction module is used to construct the winding radial coupling parameter MPCLTL model based on the loss parameters of each transmission line and the actual line structure.

[0019] The second construction module is used to construct the LP model of the axial coupling parameters between the winding discs based on the electrical parameters between the winding discs.

[0020] The third building module is used to combine the MPCLTL model and the LP model to build a full-winding MPCLTL-LP model;

[0021] The fourth construction module is used to perform high-frequency equivalent modeling of the iron core based on the iron core structural parameters, material parameters and stacking coefficient, so as to obtain the high-frequency equivalent model of the iron core.

[0022] The fifth building module is used to combine the full-winding MPCLTL-LP model and the high-frequency equivalent model of the iron core to construct a coupling model between the full winding and the iron core.

[0023] Thirdly, the present invention provides a non-transitory computer-readable storage medium for storing computer instructions, which, when executed by a processor, implement the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described in the first aspect.

[0024] Fourthly, the present invention provides a computer device including a memory and a processor, wherein the processor and the memory communicate with each other, the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described in the first aspect.

[0025] Fifthly, the present invention provides an electronic device, comprising: a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to cause the electronic device to execute instructions for implementing the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described in the first aspect.

[0026] The beneficial effects of this invention are: it can accurately model the internal windings and core of a transformer based on its physical structure and characteristics, and build and simulate the model on EMTP software. By adding a high-frequency pulse current signal to the winding side and detecting the signal on the core grounding wire, the rationality of the high-frequency pulse current detection method can be verified.

[0027] The advantages of additional aspects of the invention will be set forth more clearly in the following description or will be learned by practice of the invention. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating the construction of an equivalent model of a transformer high-frequency circuit for HFCT current analysis, as described in an embodiment of the present invention.

[0030] Figure 2 This is a framework diagram of the MPCLTL model for a single pie under EMTP as described in an embodiment of the present invention.

[0031] Figure 3 This is a framework diagram of the full-winding LP model under EMTP as described in an embodiment of the present invention.

[0032] Figure 4 This is a model framework diagram of the MPCLTL-LP full winding described in an embodiment of the present invention.

[0033] Figure 5 This is a framework diagram of the equivalent lumped capacitance model of the iron core according to an embodiment of the present invention.

[0034] Figure 6 This is a model framework diagram of the winding coupling iron core grounding wire according to an embodiment of the present invention. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0036] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as here.

[0038] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or groups thereof.

[0039] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0040] To facilitate understanding of the present invention, the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. However, the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0041] Those skilled in the art should understand that the accompanying drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily essential for implementing the present invention.

[0042] Since partial discharge is usually accompanied by high-frequency pulse current, which is a high-frequency transient process within the transformer windings, a more refined high-frequency transient model of the windings is needed. This invention provides a novel high-frequency equivalent modeling method for transformers, which can accurately model the internal windings and core of the transformer based on its physical structure and characteristics. The model is then built and simulated using EMTP software. The rationality of the high-frequency pulse current detection method is verified by adding a high-frequency pulse current signal to the winding side and detecting the signal on the core grounding wire. The novel high-frequency equivalent modeling method for transformers provided by this invention can accurately model the internal windings and core based on the transformer's physical structure and characteristics. The constructed "parallel multi-conductor lossless transmission line (MPCLTL) and lumped parameter (LP) hybrid model," abbreviated as MPCLTL-LP model, greatly reduces the matrix dimension and computational load. Through simulation analysis, the entire process of partial discharge signal generation and coupling to the core grounding wire can be intuitively observed, which is helpful for fault diagnosis and prevention.

[0043] Example 1

[0044] In this embodiment 1, a transformer high-frequency circuit equivalent model construction system for HFCT current analysis is provided, including: a first construction module for constructing a winding radial coupling parameter MPCLTL model based on the loss parameters of each transmission line and the actual line structure; a second construction module for constructing a winding axial inter-circuit coupling parameter LP model based on the winding axial inter-circuit electrical parameters; a third construction module for building a full-winding MPCLTL-LP model by combining the MPCLTL model and the LP model; a fourth construction module for performing high-frequency equivalent modeling of the core based on the core structure parameters, material parameters, and stacking coefficient to obtain a high-frequency equivalent model of the core; and a fifth construction module for constructing a coupling model between the full winding and the core by combining the full-winding MPCLTL-LP model and the high-frequency equivalent model of the core.

[0045] In this embodiment, using the system described above, a method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis is implemented, including:

[0046] S1 constructs the winding radial coupling parameter MPCLTL model.

[0047] S2 constructs an LP model of the axial inter-disc coupling parameters of the winding.

[0048] S3 builds a full-winding MPCLTL-LP model in EMTP software.

[0049] S4 performs high-frequency equivalent modeling of the iron core.

[0050] S5 constructs a coupling model between the entire winding and the core.

[0051] In step S1, the loss parameters of each transmission line are segmented and connected as lumped parameters, transforming each transmission line into a lossless transmission line connected in series with a lumped resistor, thus obtaining the MPCLTL model for each pie. Then, all the single-pie MPCLTL models are sequentially connected according to the actual structure to form the MPCLTL model for the entire winding. Compared to the MTL model for the entire winding, the MPCLTL model significantly reduces the matrix dimension and computational load, and this model can directly utilize the distributed parameter elements in EMTP for numerical simulation.

[0052] The LP model in S2 is a fully axially coupled model constructed based on the axial inter-rotor electrical parameters of the windings. Since the axial dimension is much smaller than the wavelength of the high-frequency pulse current, lumped parameters can be used for the axial electrical parameters. This model can be simulated using general circuit simulation software; the key lies in accurately calculating the electrical parameters and constructing a reasonable circuit model.

[0053] In step S3, a model is built in the EMTP software. To simplify the model and facilitate calculation, the following simplifications were made during the modeling process: only the coupling parameters between two directly opposite turns within adjacent cakes were considered. Based on the coupling method analyzed above, the axial LP model and MPCLTL model of the transformer high-voltage winding can be established in EMTP. Both models ignore the mutual inductance between corresponding turns in the upper and lower cakes.

[0054] In the modeling of the iron core in S4, since the iron core is composed of stacked silicon steel sheets coated with insulating varnish, it can be regarded as a pure capacitor series-parallel circuit under the action of high-frequency signals. This study simplifies the iron core as follows: ① the influence of the oil channels inside the iron core is ignored; ② the insulation resistance and conductivity between the silicon steel sheets in the iron core are ignored; ③ the grounding wire of the iron core is led out from the middle stack of the iron core. Based on the above simplifications, the iron core column can be divided into two perfectly equal semi-cylinders from the grounding wire lead-out position. Each semi-cylinder is further divided into several cuboids according to the multi-level circular structure of the iron core, and each cuboid contains several identical parallel-plate capacitors (in series). Therefore, based on the iron core structural parameters, material parameters, and stacking coefficient, the equivalent total capacitance of each cuboid can be calculated.

[0055] The high-frequency signal in S5 can be coupled to the iron core through the capacitance between the inner turns of the winding and the iron core, and finally flows into the ground through the iron core grounding line. Based on the physical structure of the winding and the iron core, the innermost turn of each coil can be divided into left and right halves, and each half is coupled to the iron core through its equivalent capacitance. All coils of the entire winding are coupled to the iron core in this way, thus constructing a coupling model between the entire winding and the iron core.

[0056] Example 2

[0057] like Figure 1As shown in Embodiment 2, a method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis is proposed, which specifically includes the following steps:

[0058] Step 1: Construct the radially coupled parameter MPCLTL model (Multiple Parallel Conductors Lossless Transmission Line). First, each coil of the winding is radially expanded into a segment of MTL, and the loss parameters of each transmission line are segmented and connected as lumped parameters, transforming each transmission line into a lossless transmission line connected in series with a lumped resistor, thus obtaining the MPCLTL model for each coil. Then, all the single-coil MPCLTL models are sequentially connected according to the actual structure to form the MPCLTL model of the entire winding. Compared to the full-winding MTL model, the MPCLTL model significantly reduces the matrix dimension and computational load, and this model can directly utilize the distributed parameter elements in EMTP for numerical simulation.

[0059] like Figure 2 The figure shows the MPCLTL model for a single coil in EMTP, where R represents the resistance of a single coil turn, Z represents the self-impedance of the coil turn, L represents the coil turn length, G is the mutual conductance between adjacent coil turns, C is the mutual capacitance between adjacent coil turns, C* is the capacitance of the inner coil conductor to the core, and G* is the conductance of the inner coil conductor to the core. In the MPCLTL model, only the radial inter-turn electrical parameters within the coil are considered, without considering the axial inter-coil electrical coupling between coils. In reality, the coupling relationship between adjacent coils is quite complex; the voltage difference and coupling parameters between different coil turns in two adjacent coils may differ, leading to significant differences in the coupling characteristics between different coil turns. Therefore, to simplify the model and facilitate calculation, this embodiment makes the following simplification: only the coupling parameters between two coil turns that are directly opposite each other within adjacent coils are considered.

[0060] Step Two: Constructing the Axial Inter-Disc Coupling Parameter (LP) Model of the Winding. First, the winding is discretized along the axial direction, divided into multiple equivalent units. Each unit consists of inductance, capacitance, and resistance to characterize the electromagnetic characteristics of the winding. The self-inductance of each unit is calculated from the winding's geometric parameters and magnetic flux distribution, while the mutual inductance between adjacent units is determined based on the magnetic coupling relationship. The inter-turn capacitance, inter-layer capacitance, and capacitance to ground are used to characterize the distributed capacitance characteristics of the winding, while equivalent resistance is introduced to reflect the winding's losses and damping characteristics. Finally, by establishing the connection relationships between these equivalent circuit elements, a lumped parameter (LP) equivalent circuit model of the winding is formed.

[0061] like Figure 3As shown, this is an axial LP model of the transformer high-voltage winding studied in this embodiment, established under EMTP. In the figure, G i*(i+1)-1 G represents the conductance between the first turns of cake i and cake i+1; i*(i+1)-2 This represents the capacitance between the second turn of pie i and pie i+1; the green dashed box represents a... Figure 3 The single-pie MPCLTL model is shown.

[0062] Step 3: Build the full-winding MPCLTL-LP model (a hybrid model of multi-parallel conductor zero-loss transmission line and lumped parameter model) in EMTP software. Since the MPCLTL model lacks consideration for the axial (inter-turn) electrical parameters of the winding, and the LP model lacks consideration for the radial (inter-turn) electrical parameters, these two models complement each other. By combining the MPCLTL and LP models according to the actual physical structure of the winding, the MPCLTL-PL model can be constructed. The following will describe in detail how to combine the two models.

[0063] Because the full-winding MPCLTL model is relatively complex with a large number of internal nodes, selecting appropriate nodes to combine the two models is crucial for the model's accuracy. During transient processes, the voltage and current at different locations on the same turn may vary significantly. To minimize the impact of voltage and current differences on the simulation results, this example selects the middle of each turn as the access point for the LP model, embedding the LP model into the MPCLTL model. Figure 4 The figure shows the MPCLTL-LP model of the full winding. In the figure, the red solid lines represent the connections between the turns, thus forming a complete continuous model of the full winding.

[0064] Step 4: Perform high-frequency equivalent modeling of the iron core. Since the iron core is composed of stacked silicon steel sheets coated with insulating varnish, it can be considered as a pure capacitor series-parallel circuit under high-frequency signal action. Theoretically, the capacitance between all the sheets can be calculated using the structure, size, and material parameters of the iron core, and an equivalent capacitance model of the entire iron core can be established. However, in reality, the iron core is a complex multi-level circular structure, with numerous laminations in each level of the iron core block. Furthermore, the shape, size, and number of silicon steel sheets in different iron core blocks vary, making it difficult to directly calculate the equivalent capacitance of the entire iron core. Therefore, this embodiment simplifies the iron core structure as follows: ① Ignore the influence of the internal oil channels; ② Ignore the insulation resistance and conductivity between the silicon steel sheets in the iron core; ③ The grounding wire of the iron core is led out from the middle layer of the iron core. Based on the above simplification, the iron core column can be divided into two perfectly equal semi-cylinders from the grounding wire lead-out position. Each semi-cylinder is further divided into several cuboids according to the multi-level circular structure of the iron core. Each cuboid contains several identical parallel-plate capacitors (connected in series). Therefore, based on the iron core structural parameters, material parameters, and stacking factor, the equivalent total capacitance of each cuboid can be calculated, thereby establishing a simplified model of the iron core under high-frequency signal action, such as... Figure 5 The model shown is a pure capacitive coupling model of an iron core.

[0065] Step 5: Construct a coupling model between the entire winding and the core. For example... Figure 6 As shown, high-frequency signals can be coupled to the core through the capacitance between the inner turns of the winding and the core, and finally flow into the ground through the core grounding line. Based on the physical structure of the winding and the core, the innermost turn of each coil can be divided into left and right halves, each coupling to the core through its equivalent capacitance. By coupling all coils of the entire winding to the core in this way, a coupling model between the entire winding and the core can be constructed.

[0066] Regarding the setting of model simulation parameters, this embodiment calculates the parameters of the full-winding MPCLTL-LP model for the distributed parameters. Furthermore, distributed parameters are generally related to the calculation frequency; however, frequency domain simulation is generally difficult to achieve. Instead, time-domain simulation at multiple fixed frequency points is used. In this embodiment, four frequency points are selected based on the main characteristic frequencies of partial discharge, and the distributed parameter values ​​at each frequency point are obtained, as shown in Table 1. The calculation formulas for each parameter are as follows:

[0067] Distributed resistance of copper wire: Where ρ is the resistivity of copper (Ω·m), l is the conductor length (in meters), and A is the conductor cross-sectional area.

[0068] General formula for calculating electrical conductivity: Where σ is the electrical conductivity of the insulating medium (S / m), A is the effective area of ​​the insulating layer, and d is the thickness of the insulating layer (the specific value is determined according to different structural parts).

[0069] Distributed inductance of copper conductors: Where L is the inductance per unit length (H / m); μ0 is the permeability of free space (4π×10⁻⁶). -7 H / m); μ r The relative permeability of the wire material (for copper, μ) r ≈1); l is the length of the conductor (m); r is the radius of the conductor (m).

[0070] Self-wave impedance (Ω) / wave velocity: Self-wave impedance (characteristic impedance): Wave speed: Where Z0 is the characteristic impedance (Ω); v is the propagation speed of electromagnetic waves in the winding (m / s); L is the inductance per unit length (H / m); and C is the capacitance per unit length (F / m).

[0071] General capacitance calculation formula: Where C is the capacitance (F); ε is the dielectric constant of the insulating material (F / m), ε = ε₀ε r Where ε0 is the vacuum permittivity (8.854 × 10⁻⁶). -12 F / m); ε r denoted as ρ, where ρ is the relative permittivity of the insulating material; A is the effective area between the electrodes (m²); and d is the thickness of the insulating layer between the electrodes (m).

[0072] Table 1. Values ​​of various distribution parameters at different frequency points.

[0073]

[0074] Based on the connection method between the transformer and the GIS, the integrated model of the entire winding-core is combined with the high-frequency pulse current generation model, and simulations are performed at different frequency points to realize the simulation of the entire process of partial discharge signal from generation to coupling to the core grounding wire. The high-frequency pulse simulation waveforms of each are obtained, thereby verifying that the high-frequency pulse current generated when partial discharge occurs in the winding can be coupled to the core grounding wire and thus detected by the HFCT detector.

[0075] Example 3

[0076] This embodiment 3 provides a non-transitory computer-readable storage medium for storing computer instructions. When executed by a processor, the computer instructions implement the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described above. The method includes:

[0077] Based on the loss parameters of each transmission line and combined with the actual line structure, a winding radial coupling parameter MPCLTL model is constructed.

[0078] Based on the electrical parameters between the axial discs of the windings, construct the LP model of the coupling parameters between the axial discs of the windings;

[0079] By combining the MPCLTL model and the LP model, a full-winding MPCLTL-LP model is constructed.

[0080] Based on the core structure parameters, material parameters, and stacking coefficient, a high-frequency equivalent model of the core is performed to obtain the high-frequency equivalent model of the core.

[0081] By combining the MPCLTL-LP model of the full winding and the high-frequency equivalent model of the iron core, a coupling model between the full winding and the iron core is constructed.

[0082] Example 4

[0083] This embodiment 4 provides a computer device, including a memory and a processor, wherein the processor and the memory communicate with each other, and the memory stores program instructions that can be executed by the processor. The processor calls the program instructions to execute the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described above, the method including:

[0084] Based on the loss parameters of each transmission line and combined with the actual line structure, a winding radial coupling parameter MPCLTL model is constructed.

[0085] Based on the electrical parameters between the axial discs of the windings, construct the LP model of the coupling parameters between the axial discs of the windings;

[0086] By combining the MPCLTL model and the LP model, a full-winding MPCLTL-LP model is constructed.

[0087] Based on the core structure parameters, material parameters, and stacking coefficient, a high-frequency equivalent model of the core is performed to obtain the high-frequency equivalent model of the core.

[0088] By combining the MPCLTL-LP model of the full winding and the high-frequency equivalent model of the iron core, a coupling model between the full winding and the iron core is constructed.

[0089] Example 5

[0090] This embodiment 5 provides an electronic device, including: a processor, a memory, and a computer program; wherein, the processor is connected to the memory, and the computer program is stored in the memory. When the electronic device is running, the processor executes the computer program stored in the memory to cause the electronic device to execute instructions for implementing the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described above, the method including:

[0091] Based on the loss parameters of each transmission line and combined with the actual line structure, a winding radial coupling parameter MPCLTL model is constructed.

[0092] Based on the electrical parameters between the axial discs of the windings, construct the LP model of the coupling parameters between the axial discs of the windings;

[0093] By combining the MPCLTL model and the LP model, a full-winding MPCLTL-LP model is constructed.

[0094] Based on the core structure parameters, material parameters, and stacking coefficient, a high-frequency equivalent model of the core is performed to obtain the high-frequency equivalent model of the core.

[0095] By combining the MPCLTL-LP model of the full winding and the high-frequency equivalent model of the iron core, a coupling model between the full winding and the iron core is constructed.

[0096] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0097] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0098] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0099] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment, whereby a series of operational steps are performed to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0100] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present invention.

Claims

1. A method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis, characterized in that, include: Based on the loss parameters of each transmission line and the actual line structure, a winding radial coupling parameter MPCLTL model is constructed. Each coil of the winding is radially expanded into a segment MTL, and the loss parameters of each transmission line are connected in segments as lumped parameters, so that each transmission line becomes a lossless transmission line and a lumped resistor in series, thus obtaining the MPCLTL model of each coil. Then, all the single coil MPCLTL models are connected sequentially according to the actual structure to form the MPCLTL model of the entire winding. Based on the electrical parameters between the axial discs of the windings, construct the LP model of the coupling parameters between the axial discs of the windings; A full-winding MPCLTL-LP model is constructed by combining the MPCLTL model and the LP model. This includes combining the MPCLTL model and the LP model according to the actual physical structure of the winding, selecting the middle of each turn as the access point of the LP model, and embedding the LP model into the MPCLTL model. Based on the core structure parameters, material parameters, and stacking coefficient, a high-frequency equivalent model of the core is performed to obtain the high-frequency equivalent model of the core. By combining the MPCLTL-LP model of the full winding and the high-frequency equivalent model of the iron core, a coupling model between the full winding and the iron core is constructed.

2. The method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis according to claim 1, characterized in that, The LP model is a full-winding axial coupling model constructed based on the axial inter-turn electrical parameters of the winding. Since the axial scale is much smaller than the wavelength of the high-frequency pulse current, lumped parameters are used for the axial electrical parameters. First, the winding is discretized along the axial direction and divided into multiple equivalent units. Each unit consists of inductance, capacitance, and resistance to characterize the electromagnetic characteristics of the winding. The self-inductance of each unit is calculated from the geometric parameters and magnetic flux distribution of the winding, while the mutual inductance between adjacent units is determined according to the magnetic coupling relationship. The inter-turn capacitance, inter-layer capacitance, and capacitance to ground are used to characterize the distributed capacitance characteristics of the winding, while equivalent resistance is introduced to reflect the losses and damping characteristics of the winding. Finally, by establishing the connection relationship between these equivalent circuit elements, a lumped parameter LP equivalent circuit model of the winding is formed.

3. The method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis according to claim 1, characterized in that, A full-winding MPCLTL-LP model was built in EMTP software. The following coupling method was used in the modeling process: only the coupling parameters between two directly opposite turns in adjacent discs were considered. Based on the coupling method, the axial LP model and MPCLTL model of the transformer high-voltage winding were established in EMTP. The mutual inductance between corresponding turns in the upper and lower discs was ignored in both models.

4. The method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis according to claim 1, characterized in that, The iron core is modeled as a pure capacitor series-parallel circuit. The following simplifications are made: the influence of the internal oil channels is ignored; the insulation resistance and conductivity between the silicon steel sheets are ignored; the grounding wire is led out from the middle stack of the iron core. Based on these simplifications, the iron core column is divided into two perfectly equal semi-cylinders at the grounding wire exit point. Each semi-cylinder is further divided into several cuboids according to the multi-level circular structure of the iron core. Each cuboid contains several identical parallel-plate capacitors. Therefore, based on the iron core structural parameters, material parameters, and stacking coefficient, the equivalent total capacitance of each cuboid is calculated.

5. The method for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis according to claim 1, characterized in that, High-frequency signals are coupled to the iron core through the capacitance between the inner turns of the winding and the iron core, and finally flow into the ground through the iron core grounding line. According to the physical structure of the winding and the iron core, the innermost turn of each coil is divided into left and right half turns, and each half is coupled to the iron core through its equivalent capacitance. All coils of the entire winding are coupled to the iron core in this way, and the coupling model between the entire winding and the iron core can be constructed.

6. A system for constructing an equivalent model of a transformer high-frequency circuit for HFCT current analysis, characterized in that, include: The first construction module is used to construct the winding radial coupling parameter MPCLTL model based on the loss parameters of each transmission line and the actual line structure. This includes: expanding each coil of the winding radially into a segment MTL, connecting the loss parameters of each transmission line in a lumped parameter manner, so that each transmission line becomes a lossless transmission line and is connected in series with a lumped resistor, thereby obtaining the MPCLTL model of each coil; and then connecting all the single coil MPCLTL models in sequence according to the actual structure to form the MPCLTL model of the entire winding. The second construction module is used to construct the LP model of the axial coupling parameters between the winding discs based on the electrical parameters between the winding discs. The third building module is used to combine the MPCLTL model and the LP model to build a full-winding MPCLTL-LP model; it includes: combining the MPCLTL model and the LP model according to the actual physical structure of the winding, selecting the middle of each wire turn as the access point of the LP model, and embedding the LP model into the MPCLTL model; The fourth construction module is used to perform high-frequency equivalent modeling of the iron core based on the iron core structural parameters, material parameters and stacking coefficient, so as to obtain the high-frequency equivalent model of the iron core. The fifth building module is used to combine the full-winding MPCLTL-LP model and the high-frequency equivalent model of the iron core to construct a coupling model between the full winding and the iron core.

7. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium is used to store computer instructions, which, when executed by a processor, implement the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described in any one of claims 1-5.

8. A computer device, characterized in that, The system includes a memory and a processor, which communicate with each other. The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described in any one of claims 1-5.

9. An electronic device, characterized in that, include: The device includes a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to cause the electronic device to execute instructions for implementing the transformer high-frequency circuit equivalent model construction method for HFCT current analysis as described in any one of claims 1-5.

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