A method and system for determining transient voltage distribution of a ring-type air-core reactor

Abstract

The application discloses a kind of transient voltage distribution determination methods and systems of ring type hollow reactor, it is related to the field of reactor design, the method includes obtaining the basic parameters of ring type hollow reactor;Parameter extraction is carried out on circuit parameter using the basic parameters, resistance parameter, inductance parameter and parasitic capacitance parameter are obtained;According to basic parameters, resistance parameter, inductance parameter and parasitic capacitance parameter, wideband equivalent circuit is constructed;According to wideband equivalent circuit, basic parameters, resistance parameter, inductance parameter and parasitic capacitance parameter, the voltage distribution under transient process is calculated, and the transient voltage distribution of ring type hollow reactor is obtained.The application can accurately and quickly determine the transient voltage distribution of reactor under lightning impulse voltage, improve the accuracy of reactor insulation performance evaluation, effectively solve the problem that frequency error is large and seriously depends on manual intervention in the calculation of transient voltage distribution in the prior art.

Description

Technical Field

[0001] This application relates to the field of reactor design, and in particular to a method and system for determining the transient voltage distribution of a toroidal air-core reactor. Background Technology

[0002] Flexible DC transmission technology boasts significant advantages, including strong renewable energy absorption capacity, high scalability, flexible dispatching, and low harmonic content. It can also address the problem of insufficient dynamic reactive power compensation in the system, thus gaining widespread application. Modular multilevel converters, as core equipment in flexible DC transmission systems, require towing tests on a towed test platform before deployment to verify their design correctness. Reactors, as crucial platform equipment, can achieve AC / DC superposition operation. Traditional cylindrical hollow reactors emit a large leakage magnetic field during operation, resulting in a large magnetic clearance and significantly increasing the platform's footprint and construction costs. Furthermore, in offshore wind power platforms, cylindrical hollow reactors struggle to meet the space constraints of next-generation compact offshore wind power platforms. In contrast, toroidal hollow reactors have proven their low magnetic clearance characteristics, with an external magnetic field attenuation rate far exceeding that of cylindrical hollow reactors, offering broader development prospects in towed test platforms and offshore wind power equipment integration.

[0003] The structure of the toroidal air-core reactor is as follows: the entire reactor consists of two semi-circular windings connected in parallel, each semi-circular winding containing... m × n One line cake, among which n A series of thread-shaped discs connected in parallel form a thread-shaped disc group. m Several strands of thread are strung together. All the strands are equally spaced, and each strand consists of... N The conductors are wound into a racetrack shape or a circle. During the design phase of a toroidal air-core reactor, it is necessary to simulate the transient voltage distribution of the reactor under overvoltage conditions such as lightning strikes to assess whether the current design meets the insulation requirements under harsh operating conditions. Although experiments can obtain the closest data to the actual transient voltage distribution, the experimental process is extremely time-consuming, labor-intensive, and involves a huge workload.

[0004] Therefore, there is a need for a device to calculate the transient voltage distribution of a toroidal air-core reactor. This device can directly calculate the transient voltage distribution of the reactor without conducting experiments, simply by inputting the reactor's parameters into the device, thereby shortening the reactor's design cycle.

[0005] Existing literature presents a broadband equivalent circuit for a toroidal air-core reactor and extracts parameters using the finite element method, analytical calculation method, impedance equivalent method, and empirical formula method. While this method can be used to calculate the transient voltage distribution of the reactor, it has two major drawbacks: first, the calculation process is highly dependent on manual intervention, making fully automated calculation impossible and still time-consuming and labor-intensive; second, the accuracy of the transient voltage distribution calculation is insufficient. Because its broadband equivalent circuit provides a relatively coarse and simple representation of the parasitic capacitance effect, although the waveform amplitude basically matches the measured value, the waveform frequency differs significantly from the measured value, making it impossible to accurately simulate the transient voltage distribution of the reactor. Summary of the Invention

[0006] The purpose of this application is to provide a method and system for determining the transient voltage distribution of a toroidal air-core reactor, which can accurately and quickly determine the transient voltage distribution of the reactor under lightning impulse voltage, improve the accuracy of reactor insulation performance evaluation, and effectively solve the problems of large frequency error and heavy reliance on manual intervention in the calculation of transient voltage distribution in the prior art.

[0007] To achieve the above objectives, this application provides the following solution:

[0008] In a first aspect, this application provides a method for determining the transient voltage distribution of a toroidal air-core reactor, the method comprising:

[0009] Obtain the basic parameters of the toroidal air-core reactor; the basic parameters include: total number of coils, inner radius, number of coils connected in parallel in the coil group, number of coil groups connected in series in the semi-encircling group, number of turns of the coil, inner radius of the coil, outer radius of the coil, length of the straight part of the coil, first resonant frequency of the coil impedance characteristic, length of the long side of the rectangular conductor, length of the short side of the rectangular conductor, conductivity of the conductor, relative permittivity of the conductor insulation layer, excitation source type, node number to be calculated, and time range to be calculated;

[0010] Using the aforementioned basic parameters, circuit parameters are extracted to obtain resistance parameters, inductance parameters, and parasitic capacitance parameters. The resistance parameters include the values ​​of a first resistor, a second resistor, and a third resistor. The inductance parameters include the values ​​of a first inductor, a second inductor, and a third inductor. The parasitic capacitance parameters include the values ​​of a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, the capacitance to ground, and the inter-plate capacitance.

[0011] Construct a broadband equivalent circuit based on basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters;

[0012] Based on the broadband equivalent circuit, basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters, the voltage distribution under transient processes is calculated, and the transient voltage distribution of the toroidal air-core reactor is obtained.

[0013] Secondly, this application provides a transient voltage distribution determination system for a toroidal air-core reactor, used to implement the transient voltage distribution determination method for the toroidal air-core reactor. The transient voltage distribution determination system for the toroidal air-core reactor includes: an input / output unit, a reactor parameter storage unit, a parameter extraction unit, a circuit parameter storage unit, a broadband equivalent circuit construction unit, and a transient voltage distribution determination unit.

[0014] The input / output unit is used to input the basic parameters of the toroidal air-core reactor and to display the calculation results;

[0015] The reactor parameter storage unit is used to store the basic parameters of the toroidal air-core reactor.

[0016] The parameter extraction unit is used to extract circuit parameters using the basic parameters to obtain resistance parameters, inductance parameters, and parasitic capacitance parameters.

[0017] The circuit parameter storage unit is used to store resistance parameters, inductance parameters, and parasitic capacitance parameters;

[0018] The broadband equivalent circuit construction unit is used to construct a broadband equivalent circuit based on the basic parameters stored in the reactor parameter storage unit and the resistance, inductance and parasitic capacitance parameters stored in the circuit parameter storage unit.

[0019] The transient voltage distribution determination unit is used to calculate the voltage distribution during the transient process based on the broadband equivalent circuit, basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters.

[0020] Optionally, the input / output unit includes: an input panel, an input display, an output display, and an external storage device.

[0021] According to the specific embodiments provided in this application, this application has the following technical effects:

[0022] This application provides a method and system for determining the transient voltage distribution of a toroidal air-core reactor. It utilizes the basic parameters of the toroidal air-core reactor to extract circuit parameters, obtaining resistance, inductance, and parasitic capacitance parameters. Furthermore, it constructs a broadband equivalent circuit including parasitic capacitance parameters, allowing for a more refined characterization of the parasitic capacitance effect. This application can quickly and accurately calculate the transient voltage distribution of a toroidal air-core reactor under lightning impulse voltage without relying on experimental measurements or manual intervention. The calculated waveforms, in terms of both amplitude and frequency, are in good agreement with actual results. Therefore, it can reliably obtain the voltage values ​​experienced by the reactor at different locations and times when subjected to lightning overvoltage, providing a reliable basis for determining whether the current structure meets insulation requirements. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating a method for determining the transient voltage distribution of a toroidal air-core reactor according to an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of the transient voltage distribution determination system for a type of air-core reactor according to an embodiment of this application;

[0026] Figure 3 A three-dimensional diagram showing the overall hardware structure of a transient voltage distribution determination system for a type of air-core reactor in one embodiment of this application.

[0027] Figure 4 This is a front view of the hardware structure corresponding to the transient voltage distribution determination system of a type of air-core reactor in one embodiment of this application;

[0028] Figure 5 This is a left-side view of the hardware structure corresponding to the transient voltage distribution determination system for a type of air-core reactor in one embodiment of this application;

[0029] Figure 6 This is a right-side view of the hardware structure corresponding to the transient voltage distribution determination system for a type of air-core reactor in one embodiment of this application;

[0030] Figure 7 This is a top view of the hardware structure corresponding to the transient voltage distribution determination system of a type of air-core reactor in one embodiment of this application;

[0031] Figure 8This is a rear view of the hardware structure corresponding to the transient voltage distribution determination system of a type of air-core reactor in one embodiment of this application;

[0032] Figure 9 A schematic diagram of the region division in the finite element model of the electrostatic field of a wire disc;

[0033] Figure 10 Examples of finite element models of the equivalent electrostatic field of a coil and an equivalent electrostatic field of a reactor are shown below.

[0034] Figure 11 This is a diagram showing the structure of the pie chart module;

[0035] Figure 12 This is a schematic diagram showing the inter-pane capacitor connection method between two adjacent pancake modules;

[0036] Figure 13 This is a schematic diagram of the inter-pane capacitor connection method between two adjacent pancake group modules;

[0037] Figure 14 This is a schematic diagram of the inter-pane capacitor connection method between semi-circular groups;

[0038] Figure 15 This is the broadband equivalent circuit of a toroidal air-core reactor;

[0039] Figure 16 This diagram shows a comparison between the calculated and measured transient voltages of nodes 2 and 8 of the reactor used in a specific embodiment under a 1.2 / 50μs lightning strike. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] In one exemplary embodiment, such as Figure 1 As shown, a method for determining the transient voltage distribution of a toroidal air-core reactor is provided, comprising the following steps S101 to S104: Wherein:

[0043] S101, Obtain the basic parameters of the toroidal air-core reactor; the basic parameters include: total number of coils, inner radius, number of coils connected in parallel in the coil group, number of coil groups connected in series in the semi-encircling group, number of turns of the coil, inner radius of the coil, outer radius of the coil, length of the straight part of the coil, first resonant frequency of the coil impedance characteristic, length of the long side of the rectangular conductor, length of the short side of the rectangular conductor, conductivity of the conductor, relative permittivity of the conductor insulation layer, excitation source type, node number to be calculated, and time range to be calculated;

[0044] S102, using the basic parameters, the circuit parameters are extracted to obtain resistance parameters, inductance parameters, and parasitic capacitance parameters; the resistance parameters include: the values ​​of a first resistor, a second resistor, and a third resistor; the inductance parameters include: the values ​​of a first inductor, a second inductor, and a third inductor; the parasitic capacitance parameters include: the values ​​of a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, the capacitance to ground, and the inter-plate capacitance;

[0045] S102 specifically includes:

[0046] Using formula Determine the value of the first resistor R 1;

[0047] Using formula Determine the value of the second resistor R 2;

[0048] Using formula Determine the value of the third resistor R 3;

[0049] Construct a finite element model of the magnetic field of a toroidal air-core reactor; and determine the value of the first inductance based on the finite element model of the magnetic field. L 1 and the value of self-induction L 0;

[0050] Using formula Determine the value of the second inductor L 2;

[0051] Using formula Determine the value of the third inductor L 3;

[0052] Using formula Determine the value of the first capacitor C t1 ;

[0053] Using formula Determine the value of the second capacitor C t2 ;

[0054] Using formula Determine the value of the third capacitor C t3 ;

[0055] Using formula Determine the value of the fourth capacitor C t4 ;

[0056] Using formula Determine the value of the fifth capacitor C t5 ;

[0057] Using a system of equations Determine the values ​​of the capacitance to ground and the capacitance between the coils;

[0058] in, n This represents the number of parallel thread balls in the thread ball group. m This represents the number of connected coil groups in the semi-circular group. N Let μ be the number of turns of the coil, and μ0 be the permeability in vacuum. This is the first resonant frequency of the coil's impedance characteristic. Let be the length of the longer side of the rectangular conductor. b Let be the length of the shorter side of the rectangular conductor. S This represents the total number of coils in the reactor. σ Let be the electrical conductivity of the conductor. r 0 is the inner radius of the reactor. r 1 represents the inner radius of the line disc. r 2 is the outer radius of the line disc. The ordinal number of the line disc. H Let π be the length of the straight section of the disc, π be pi, and ε₀ be the dielectric constant of vacuum. W 00 U1 represents the electrostatic energy value of the equivalent electrostatic field finite element model of the coil, and U2 represents the potentials at both ends of the broadband equivalent circuit of the coil, respectively. W x and W y represents the electrostatic energy expression of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the electrostatic energy expression of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the capacitance to ground, respectively. [U] represents the node voltage column vector, and T represents the transpose. C x] and [ C [y] represents the node capacitance matrix of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors, and the node capacitance matrix of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the capacitance to ground, respectively. and These represent the electrostatic field energy when the boundary of the solution domain of the equivalent electrostatic field finite element model of the toroidal hollow reactor is set to 0 potential and the electrostatic field energy when the boundary of the solution domain is not set to any potential, respectively.

[0059] The process of constructing the finite element model of the magnetic field of the toroidal hollow reactor is as follows:

[0060] S1 divides the wire disc into three regions: a high-potential region, an insulating layer, and a low-potential region, and as follows: Figure 8 As shown; the width of each region is an integer multiple of the short side length of the rectangular conductor; the width of the insulation layer is the short side length of the rectangular conductor;

[0061] S2, sequentially change the widths of the high-potential region and the low-potential region, so that the ratio of the width of the high-potential region to the length of the short side of the rectangular wire is successively 1 to... N -2;

[0062] S3, Calculate the electrostatic energy of the finite element model of the electrostatic field of the pancake under different ratios when no potential is set at the boundary of the solution domain. W ;

[0063] S4, according to | W - W 0|The width of each region at its minimum value determines the equivalent electrostatic field finite element model of the line disc; where, W 0 represents the estimated electrostatic energy of the equivalent electrostatic field finite element model of the line disc;

[0064] S5. Based on the equivalent electrostatic field finite element model of the coil, the equivalent electrostatic field finite element model of the symmetrical toroidal hollow reactor is used.

[0065] S103, a wideband equivalent circuit is constructed based on the basic parameters, resistance parameters, inductance parameters and parasitic capacitance parameters;

[0066] S103 specifically includes:

[0067] S31, connect the first resistor and the first inductor in series to form the first composite branch;

[0068] S32, the second resistor and the second inductor are connected in series to form the second composite branch;

[0069] S33, connects the third resistor and the third inductor in series to form the third composite branch;

[0070] S34, a first capacitor is connected in parallel across the two ends of the first composite branch to form a first wire pancake module; a second capacitor is connected in parallel across the two ends of the second composite branch to form a second wire pancake module; a third capacitor is connected in parallel across the two ends of the third composite branch to form a third wire pancake module.

[0071] S35, connect the first wire pancake module, the second wire pancake module, and the third wire pancake module in series; connect the fifth capacitor in parallel across the first wire pancake module and the second wire pancake module; connect the fourth capacitor in parallel across the second wire pancake module and the third wire pancake module to form a quasi-wire pancake module;

[0072] S36, with parallel ground capacitors connected between the two ends of the quasi-line module and the ground respectively, to form a quasi-line module;

[0073] S37, n A series of wire disc modules are connected in parallel, and inter-disc capacitors are connected between the terminals of adjacent wire disc modules. Then, the inter-disc capacitors that are short-circuited due to parallel connection are removed to form a wire disc group module. n This represents the number of parallel line-shaped modules in the line-shaped module group.

[0074] S38, m A series of wire pancake modules are connected in series, and inter-pancake capacitors are connected between the terminals of adjacent wire pancake modules. Then, the inter-pancake capacitors that are short-circuited due to series connection are removed to form a semi-circular module. m This represents the number of wire disc modules connected in series within the semi-encircling module;

[0075] S39. Connect the two semi-encircling modules in parallel. Connect the inter-pane capacitor between the terminals of the first and last pane group modules of the two semi-encircling modules. Then remove the inter-pane capacitor that was short-circuited due to the parallel connection to obtain the broadband equivalent circuit of the toroidal air-core reactor.

[0076] S104 calculates the voltage distribution during the transient process based on the broadband equivalent circuit, basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters, thus obtaining the transient voltage distribution of the toroidal air-core reactor.

[0077] S104 specifically includes:

[0078] Get the type of the currently applied stimulus source;

[0079] Generate a circuit simulation file based on the broadband equivalent circuit and the type of the currently applied excitation source;

[0080] Based on the circuit simulation file, the transient voltage distribution of the toroidal air-core reactor is calculated;

[0081] The transient voltage distribution waveform is determined based on the calculation results.

[0082] In one exemplary embodiment, such as Figure 2 As shown, a transient voltage distribution determination system for a toroidal air-core reactor is provided, comprising: an input / output unit, a reactor parameter storage unit, a parameter extraction unit, a circuit parameter storage unit, a broadband equivalent circuit construction unit, and a transient voltage distribution determination unit;

[0083] The input / output unit is used to input the basic parameters of the toroidal air-core reactor and to display the calculation results;

[0084] The reactor parameter storage unit is used to store the basic parameters of the toroidal air-core reactor.

[0085] The parameter extraction unit is used to extract circuit parameters using the basic parameters to obtain resistance parameters, inductance parameters, and parasitic capacitance parameters.

[0086] The circuit parameter storage unit is used to store resistance parameters, inductance parameters, and parasitic capacitance parameters;

[0087] The broadband equivalent circuit construction unit is used to construct a broadband equivalent circuit based on the basic parameters stored in the reactor parameter storage unit and the resistance, inductance and parasitic capacitance parameters stored in the circuit parameter storage unit.

[0088] The transient voltage distribution determination unit is used to calculate the voltage distribution during the transient process based on the broadband equivalent circuit, basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters.

[0089] The input / output unit includes an input panel, an input display, an output display, and an external storage device. That is, the input / output unit includes an input subunit and an output subunit; the basic parameters required for calculating the transient voltage distribution of the toroidal air-core reactor can be manually input on the input panel, and the required and input basic parameters can be viewed on the input display.

[0090] Corresponding to the system provided in this application, a specific hardware structure is provided, such as... Figures 3-8 As shown, the hardware structure includes an input display 1, an input panel 2, an output display 3, a USB interface 4, a power switch 5, a heat dissipation vent 6, a main housing 7, an internal computing system 8, and a power interface 9.

[0091] The internal calculation system includes the following units: a reactor parameter storage unit, a parameter extraction unit, a circuit parameter storage unit, a broadband equivalent circuit construction unit, and a transient voltage distribution determination unit. The parameter extraction unit comprises three parts: a resistance parameter extraction subunit, an inductance parameter extraction subunit, and a parasitic capacitance parameter extraction subunit. Resistance parameters are obtained from the resistance parameter extraction subunit within the parameter extraction unit; inductance parameters are obtained from the inductance parameter extraction subunit within the parameter extraction unit; and parasitic capacitance parameters are obtained from the parasitic capacitance parameter extraction subunit within the parameter extraction unit.

[0092] The resistance parameter extraction subunit and the inductance parameter extraction subunit perform calculations based on the data from the reactor parameter storage unit; the parasitic capacitance parameter extraction subunit performs calculations based on the data from the reactor parameter storage unit and the inductance parameter extraction subunit.

[0093] The transient voltage distribution determination unit generates the required transient voltage distribution waveform of the toroidal air-core reactor based on the broadband equivalent circuit construction unit and the reactor parameter storage unit, and outputs the transient voltage distribution waveform of the toroidal air-core reactor to the output display. If "Export waveform" is selected, the transient voltage distribution waveform data is exported to an external storage device.

[0094] As a specific embodiment, the workflow of the resistance parameter extraction subunit is as follows:

[0095] 1) Read basic parameters from the reactor parameter storage unit; the basic parameters read include: total number of coils, inner radius, number of coils connected in parallel in the coil group, number of coil groups connected in series in the semi-wound group, number of turns of the coil, inner radius of the coil, outer radius of the coil, length of the straight part of the coil, first resonant frequency of the coil impedance characteristic, length of the long side of the rectangular conductor, length of the short side of the rectangular conductor, and conductivity of the conductor.

[0096] 2) The resistance parameter, i.e., the value of the first resistance, is obtained using the following formula. R 1. The value of the second resistor R 2. The value of the third resistor R 3. Perform the calculation:

[0097] (1)

[0098] (2)

[0099] (3)

[0100] In the formula, n This represents the number of parallel thread balls in the thread ball group. m This represents the number of wire disc modules connected in series within the semi-encircling module. N Let μ be the number of turns of the coil, and μ0 be the permeability in vacuum. This is the first resonant frequency of the coil's impedance characteristic. Let be the length of the longer side of the rectangular conductor. b Let be the length of the shorter side of the rectangular conductor. S This represents the total number of coils in the reactor. σ Let be the electrical conductivity of the conductor. r 0 is the inner radius of the reactor. r 1 represents the inner radius of the line disc. r 2 is the outer radius of the line disc. H Let π be the length of the straight section of the disc, and π be the value of pi.

[0101] The workflow of the inductor parameter extraction subunit is as follows:

[0102] 1) Read basic parameters from the reactor parameter storage unit; the basic parameters currently read include: total number of coils, inner radius, number of turns of coils, inner radius of coils, outer radius of coils, length of straight section of coils, length of long side of rectangular conductor and length of short side of rectangular conductor.

[0103] 2) Constructing the finite element model of the reactor's magnetic field:

[0104] 2.1) Construct the structure of the reactor based on the basic parameters. Each coil of the reactor is a single geometric body in the shape of a ring racetrack, which does not require detailed modeling.

[0105] 2.2) Set each coil as a uniform multi-turn numerical coil, and the coil excitation is current excitation.

[0106] 3) Determine the value of the first inductance based on the finite element model of the magnetic field. L 1 and the value of self-induction L 0.

[0107] 4) Use the following formula to determine the value of the second inductor. L The values ​​of 2 and the third inductor L 3. Perform the calculation:

[0108] (4)

[0109] (5)

[0110] In the formula, S This represents the total number of coils in the reactor. r 0 is the inner radius of the reactor. r 2 is the outer radius of the line disc. Let μ be the ordinal number of the coil, and μ0 be the permeability in vacuum. Let be the length of the longer side of the rectangular conductor. b is the length of the shorter side of the rectangular conductor.

[0111] The workflow of the parasitic capacitance parameter extraction subunit is as follows:

[0112] 1) Read basic parameters from the reactor parameter storage module; the basic parameters currently read include: total number of coils, inner radius, number of coils connected in parallel in the coil group, number of coil groups connected in series in the semi-wrap group, number of turns of the coil, inner radius of the coil, outer radius of the coil, length of the straight part of the coil, first resonant frequency of the coil impedance characteristic, length of the long side of the rectangular conductor, length of the short side of the rectangular conductor, and relative permittivity of the conductor insulation layer.

[0113] 2) Obtain the self-inductance value from the inductance parameter extraction sub-unit. L 0.

[0114] 3) Use the following formula to initialize the first capacitor. C t10 Perform the calculation:

[0115] (6)

[0116] In the formula, f This is the first resonant frequency of the impedance characteristic of the coil. L 0 represents the value of self-inductance.

[0117] 4) Use the following formula to estimate the electrostatic energy of the equivalent electrostatic field finite element model of the coil. W Calculate using 0:

[0118] (7)

[0119] In the formula, C t10 Let be the initial value of the first capacitor. U 1 and U 2. Take 2V and 1V respectively.

[0120] 5) Estimated electrostatic energy using the finite element model of the equivalent electrostatic field of the coil. W 0. Finite element models of the equivalent electrostatic field of the coil and the toroidal hollow reactor are constructed. The specific process for constructing the equivalent electrostatic field finite element model is as follows:

[0121] 5.1) Divide the wire disc into three regions: a high-potential region, an insulation layer, and a low-potential region, forming three "tracks," such as... Figure 9 As shown.

[0122] 5.2) Let the width of each “track” be an integer multiple of the short side length of the rectangular conductor, and the width of the insulation layer be the short side length of the rectangular conductor.

[0123] 5.3) The potential of the high potential region is set to... The potential of the low potential region is set to , and U 1 and U 2. The following relationship exists:

[0124] (8)

[0125] In the formula, r 1 represents the inner radius of the line disc. r 2 is the outer radius of the line disc. H The length of the straight section of the line disc. N The number of turns of the coil. z This is the ratio of the width of the high-potential region to the length of the shorter side of the rectangular conductor. U 1 andU 2. Take 2V and 1V respectively, and π as the value of pi.

[0126] 5.4) Sequentially change the widths of the high-potential region and the low-potential region, so that the ratio of the width of the high-potential region to the length of the short side of the rectangular conductor is successively 1 to... N -2, N Given the number of turns of the coil, calculate the electrostatic energy of the finite element model of the coil's electrostatic field under different region widths when no potential is set at the solution domain boundary. W Select | W - W 0|The width of each region at its minimum is obtained, thus yielding the equivalent electrostatic field finite element model of the line disc. W 0 represents the estimated electrostatic energy of the equivalent electrostatic field finite element model of the line disc.

[0127] 5.5) Using the equivalent electrostatic field finite element model of a symmetrical toroidal hollow reactor, such as... Figure 10 As shown.

[0128] 6) Calculate the electrostatic energy value of the equivalent electrostatic field finite element model of the coil based on the equivalent electrostatic field finite element model of the coil. W 00 .

[0129] 7) In the finite element model of the equivalent electrostatic field of the reactor, give 2 n Adjacent line discs U 1 and U 2. Take 2V and 1V respectively, and the other coils... U 1 and U Both are set to 0V. n The number of parallel wire disc modules in the wire disc group module; calculate the electrostatic energy of the equivalent electrostatic field finite element model of the toroidal hollow reactor when the boundary of the solution domain is set to 0 potential. .

[0130] 8) In the finite element model of the equivalent electrostatic field of the reactor, give 2 n Adjacent line discs U 1 and U 2. Take 2V and 1V respectively, and the other coils... U 1 and U Both are set to 0V. n The number of parallel wire disc modules in the wire disc group module; calculate the electrostatic energy of the equivalent electrostatic field finite element model of the toroidal hollow reactor when the boundary of the solution domain is not set with a potential. .

[0131] 9) Calculate the value of the first capacitor using the following formula. C t1 :

[0132] (9)

[0133] In the formula, W 00 Let be the value of the electrostatic energy in the finite element model of the equivalent electrostatic field of the coil. U 1 and U 2. Take 2V and 1V respectively.

[0134] 10) Calculate the value of the second capacitor using the following formula. C t2 The value of the third capacitor C t3 The value of the fourth capacitor C t4 and the value of the fifth capacitor C t5 :

[0135] (10)

[0136] (11)

[0137] (12)

[0138] (13)

[0139] In the formula, H The length of the straight section of the line disc. S This represents the total number of coils in the reactor. Let be the length of the longer side of the rectangular conductor. b Let be the length of the shorter side of the rectangular conductor. r 1 represents the inner radius of the line disc. r 2 is the outer radius of the coil, and ε0 is the dielectric constant of vacuum.

[0140] 11) Generate the electrostatic field energy expression for the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the electrostatic field energy expression for the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the capacitance to ground:

[0141] 11.1) Generate the column vector of the node capacitance matrix of the toroidal air-core reactor after removing the second to fifth capacitors:

[0142] ;

[0143] ;

[0144] ;

[0145] ;

[0146] ;

[0147] ;

[0148] ;

[0149] ;

[0150] In the formula, , n This represents the number of parallel thread balls in the thread ball group. m This represents the number of cascaded pie block modules in the semi-encircling module, with the superscript T indicating transpose.

[0151] 11.2) Generate the broadband equivalent circuit of the toroidal air-core reactor by removing the node capacitance matrix of capacitors 2 to 5. :

[0152] ;

[0153] In the formula, m This represents the number of cascaded pie block modules within the semi-circular group module.

[0154] 11.3) Generate the column vector of the node capacitance matrix of the toroidal air-core reactor after removing the second to fifth capacitors and the capacitance to ground:

[0155] ;

[0156] ;

[0157] ;

[0158] ;

[0159] ;

[0160] ;

[0161]

[0162]

[0163] In the formula, capacitance , n This represents the number of parallel thread balls in the thread ball group. m This represents the number of cascaded pie block modules in the semi-encircling module, with the superscript T indicating transpose.

[0164] 11.4) Generate the broadband equivalent circuit of the toroidal air-core reactor by removing the node capacitance matrix of capacitors 2 to 5 and the capacitance to ground. :

[0165] ;

[0166] In the formula, m This represents the number of cascaded pie block modules within the semi-circular group module.

[0167] 11.5) Generate voltage column vectors :

[0168] ;

[0169] In the formula, m The number of cascaded pie block modules in the semi-circular group module, where T represents transpose.

[0170] 11.6) Generate the electrostatic field energy expressions for the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the electrostatic field energy expressions for the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the capacitance to ground:

[0171] ;

[0172] ;

[0173] In the formula, T represents transpose.

[0174] 12) Solve for the value of the capacitance to ground C using the following system of equations. g The capacitance C between the two discs p :

[0175] ;

[0176] In the formula, To solve the electrostatic energy of the equivalent electrostatic field of a toroidal hollow reactor when the boundary of the solution domain is set to 0 potential. Solve the electrostatic energy of the equivalent electrostatic field of a toroidal hollow reactor when no potential is set at the boundary of the domain.

[0177] The workflow of the broadband equivalent circuit construction unit is as follows:

[0178] 1) Read basic parameters from the reactor parameter storage unit; the basic parameters read include: the total number of coils, the number of coils connected in parallel in the coil group, and the number of coil groups connected in series in the semi-wound group.

[0179] 2) The parameters read from the circuit parameter storage unit are: the value of the first resistor, the value of the second resistor, the value of the third resistor, the value of the first inductor, the value of the second inductor, the value of the third inductor, the final value of the first capacitor, the value of the second capacitor, the value of the third capacitor, the value of the fourth capacitor, the value of the fifth capacitor, the value of the capacitance to ground, and the value of the inter-plate capacitance.

[0180] 3) A circuit program for generating a broadband equivalent circuit based on a toroidal air-core reactor. This circuit program is written in SPICE language for the broadband equivalent circuit of a toroidal air-core reactor.

[0181] The broadband equivalent circuit of a toroidal air-core reactor is as follows:

[0182] 1) The first composite branch, the second composite branch, and the third composite branch are respectively formed by the first resistor and the first inductor connected in series, the second resistor and the second inductor connected in series, and the third resistor and the third inductor connected in series.

[0183] 2) Connect the first capacitor, the second capacitor, and the third capacitor in parallel at both ends of the first composite branch, the two ends of the second composite branch, and the two ends of the third composite branch to form the first wire pancake module, the second wire pancake module, and the third wire pancake module, respectively.

[0184] 3) Constructing the guideline pie module:

[0185] 3.1) Connect the first-line pancake module, the second-line pancake module, and the third-line pancake module in series.

[0186] 3.2) Further, a fifth capacitor is connected in parallel across the first and second line pancake modules, and a fourth capacitor is connected in parallel across the second and third line pancake modules.

[0187] 4) Connect ground capacitors in parallel between the two ends of the quasi-circuit module and the ground to form the quasi-circuit module. The quasi-circuit module is as follows: Figure 11 As shown.

[0188] 5) n Several wire disc modules are connected in parallel, and inter-disc capacitors are connected between the terminals of adjacent wire disc modules. Then, the inter-disc capacitors that are short-circuited due to parallel connection are removed to form a wire disc group module:

[0189] 5.1) n The pancake modules are connected in parallel. n This represents the number of parallel thread pieces in the thread piece group.

[0190] 5.2) Further, let the terminals of two adjacent wire disc modules be a, b and c, d respectively; where a and c, b and d are directly connected because they are connected in parallel.

[0191] 5.3) Further, inter-pane capacitors are connected between terminals a and d, and between terminals b and c, of two adjacent pane modules. This is done for all adjacent pane modules. The connection method of the inter-pane capacitors between two adjacent pane modules is as follows: Figure 12 As shown.

[0192] 6) m Several wire pancake modules are connected in series, and inter-pancake capacitors are connected between the terminals of adjacent wire pancake modules. Then, the inter-pancake capacitors that are short-circuited due to series connection are removed, forming a semi-encircling module:

[0193] 6.1) will m The modules are connected in series. m This represents the number of cascaded pie block modules within the semi-circular group module.

[0194] 6.2) Further, let the terminals of two adjacent wire disc modules be a, b and c, d respectively; where b and c are directly connected because they are connected in series.

[0195] 6.3) Further, inter-pane capacitors are connected between a and b, between c and d, and between a and d. This is done for all adjacent line pane group modules. The connection method of the inter-pane capacitors between two adjacent line pane group modules is as follows: Figure 13 As shown.

[0196] 7) Connect the two semi-encircling modules in parallel. Connect inter-pane capacitors between the terminals of the first and last pane group modules of the two semi-encircling modules. Then remove the inter-pane capacitors that are short-circuited due to the parallel connection to construct the broadband equivalent circuit of the toroidal air-core reactor:

[0197] 7.1) Connect the two semi-encircling modules in parallel.

[0198] 7.2) Further, let the terminals of the first piece group module of the two semi-encircling group modules be a, b and c, d respectively; where a and c are directly connected because the semi-encircling groups are connected in parallel. Let the terminals of the last piece group module of the two semi-encircling group modules be e, f and g, h respectively; where f and h are directly connected because the semi-encircling groups are connected in parallel.

[0199] 7.3) Further, inter-pane capacitors are connected between a and d, between b and c, and between b and d. Inter-pane capacitors are also connected between e and h, between f and g, and between e and g. The connection method of the inter-pane capacitors between the semi-circular groups is as follows: Figure 14 As shown.

[0200] 7.4) Obtain the broadband equivalent circuit of the toroidal air-core reactor, such as... Figure 15 As shown.

[0201] The workflow of the transient voltage distribution determination unit is as follows:

[0202] 1) Read the type of excitation source to be applied from the reactor parameter storage unit.

[0203] 2) Obtain the circuit program from the broadband equivalent circuit construction unit.

[0204] 3) Generate a circuit simulation file based on 1) and 2). This file is constructed by adding excitation sources to the SPICE language program of the broadband equivalent circuit in 2).

[0205] 4) Run the circuit simulation file to calculate the transient voltage distribution of the toroidal air-core reactor.

[0206] 5) Output transient voltage distribution waveform to the output display.

[0207] 6) If you select "Yes, export waveform", the transient voltage distribution waveform data will be exported to the external storage device.

[0208] like Figure 16 As shown, the transient voltage distribution of the toroidal air-core reactor with parameters in Table 1 under a 1.2 / 50μs lightning impulse at nodes 2 and 8 from 0 to 10μs is calculated, and the waveforms that need to be exported are selected.

[0209] Table 1

[0210]

[0211] The system provided in this application only requires input of the basic parameters of the toroidal air-core reactor to automatically calculate the transient voltage distribution under a certain excitation condition, saving time and effort. This application proposes a more refined broadband equivalent circuit and parameter extraction method. The established broadband equivalent circuit provides a more refined characterization of the parasitic capacitance effect. Both the amplitude and frequency of the waveform are basically consistent with the actual measurement, and the accuracy is higher.

[0212] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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, they should be considered to be within the scope of this specification.

[0213] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for determining the transient voltage distribution of a toroidal air-core reactor, characterized in that, The method for determining the transient voltage distribution of the toroidal air-core reactor includes: Obtain the basic parameters of the toroidal air-core reactor; the basic parameters include: total number of coils, inner radius, number of coils connected in parallel in the coil group, number of coil groups connected in series in the semi-encircling group, number of turns of the coil, inner radius of the coil, outer radius of the coil, length of the straight part of the coil, first resonant frequency of the coil impedance characteristic, length of the long side of the rectangular conductor, length of the short side of the rectangular conductor, conductivity of the conductor, relative permittivity of the conductor insulation layer, excitation source type, node number to be calculated, and time range to be calculated; Using the aforementioned basic parameters, circuit parameters are extracted to obtain resistance parameters, inductance parameters, and parasitic capacitance parameters. The resistance parameters include the values ​​of a first resistor, a second resistor, and a third resistor. The inductance parameters include the values ​​of a first inductor, a second inductor, and a third inductor. The parasitic capacitance parameters include the values ​​of a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, the capacitance to ground, and the inter-plate capacitance. Construct a broadband equivalent circuit based on basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters; Based on the broadband equivalent circuit, basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters, the voltage distribution under transient process is calculated, and the transient voltage distribution of the toroidal air-core reactor is obtained. The step of extracting circuit parameters using the basic parameters to obtain resistance parameters, inductance parameters, and parasitic capacitance parameters specifically includes: Using formula Determine the value of the first resistor R 1; Using formula Determine the value of the second resistor R 2; Using formula Determine the value of the third resistor R 3; Construct a finite element model of the magnetic field of a toroidal air-core reactor; and determine the value of the first inductance based on the finite element model of the magnetic field. L 1 and the value of self-induction L 0; Using formula Determine the value of the second inductor L 2; Using formula Determine the value of the third inductor L 3; Using formula Determine the value of the first capacitor C t1 ; Using formula Determine the value of the second capacitor C t2 ; Using formula Determine the value of the third capacitor C t3 ; Using formula Determine the value of the fourth capacitor C t4 ; Using formula Determine the value of the fifth capacitor C t5 ; Using a system of equations Determine the values ​​of the capacitance to ground and the capacitance between the coils; in, n This represents the number of parallel thread balls in the thread ball group. m This represents the number of connected coil groups in the semi-circular group. N Let μ be the number of turns of the coil, and μ0 be the permeability in vacuum. This is the first resonant frequency of the coil's impedance characteristic. Let be the length of the longer side of the rectangular conductor. b Let be the length of the shorter side of the rectangular conductor. S This represents the total number of coils in the reactor. σ Let be the electrical conductivity of the conductor. r 0 is the inner radius of the reactor. r 1 represents the inner radius of the line disc. r 2 is the outer radius of the line disc. The ordinal number of the line disc. H Let π be the length of the straight section of the disc, π be pi, and ε₀ be the dielectric constant of vacuum. W 00 U1 represents the electrostatic energy value of the equivalent electrostatic field finite element model of the coil, and U2 represents the potentials at both ends of the broadband equivalent circuit of the coil, respectively. W x and W y Let U represent the electrostatic field energy expressions of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors, and the electrostatic field energy expressions of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the capacitance to ground, respectively. [U] represents the node voltage column vector, and T represents the transpose. C x ]and[ C y [ ] respectively represent the node capacitance matrix of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors, and the node capacitance matrix of the broadband equivalent circuit of the toroidal air-core reactor after removing the second to fifth capacitors and the capacitance to ground. and These represent the electrostatic field energy when the boundary of the solution domain of the equivalent electrostatic field finite element model of the toroidal hollow reactor is set to 0 potential and the electrostatic field energy when the boundary of the solution domain is not set to any potential, respectively.

2. The method for determining the transient voltage distribution of a toroidal air-core reactor according to claim 1, characterized in that, The construction of the magnetic field finite element model for the toroidal hollow reactor specifically includes: The wire disc is divided into three regions: a high-potential region, an insulation layer, and a low-potential region. The width of each region is an integer multiple of the short side length of the rectangular wire. The width of the insulation layer is the same as the short side length of the rectangular wire. The widths of the high-potential and low-potential regions are successively changed, so that the ratio of the width of the high-potential region to the length of the short side of the rectangular wire is successively 1 to... N -2; Calculate the electrostatic energy of the finite element model of the electrostatic field of the disc under different ratios when no potential is set at the boundary of the solution domain. W ; According to | W - W 0|The width of each region at its minimum value determines the equivalent electrostatic field finite element model of the line disc; where, W 0 represents the estimated electrostatic energy of the equivalent electrostatic field finite element model of the line disc; Based on the equivalent electrostatic field finite element model of the coil, the equivalent electrostatic field finite element model of the symmetrical toroidal hollow reactor is used.

3. The method for determining the transient voltage distribution of a toroidal air-core reactor according to claim 1, characterized in that, A broadband equivalent circuit is constructed based on the basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters, specifically including: The first resistor and the first inductor are connected in series to form the first composite branch; The second resistor and the second inductor are connected in series to form the second composite branch; The third resistor and the third inductor are connected in series to form the third composite branch; A first capacitor is connected in parallel across the two ends of the first composite branch to form a first wire pancake module; a second capacitor is connected in parallel across the two ends of the second composite branch to form a second wire pancake module; and a third capacitor is connected in parallel across the two ends of the third composite branch to form a third wire pancake module. Connect the first, second, and third line pancake modules in series; connect the fifth capacitor in parallel across the first and second line pancake modules; connect the fourth capacitor in parallel across the second and third line pancake modules to form a standard line pancake module. A ground capacitor is connected in parallel between each end of the quasi-circle module and the ground to form the quasi-circle module; Will n A series of wire disc modules are connected in parallel, and inter-disc capacitors are connected between the terminals of adjacent wire disc modules. Then, the inter-disc capacitors that are short-circuited due to parallel connection are removed to form a wire disc group module. n This represents the number of parallel line-shaped modules in the line-shaped module group. Will m A series of wire pancake modules are connected in series, and inter-pancake capacitors are connected between the terminals of adjacent wire pancake modules. Then, the inter-pancake capacitors that are short-circuited due to series connection are removed to form a semi-circular module. m This represents the number of wire disc modules connected in series within the semi-encircling module; Two semi-encircling modules are connected in parallel. An inter-panel capacitor is connected between the terminals of the first and last pancake modules of the two semi-encircling modules. Then, the inter-panel capacitor that was short-circuited due to the parallel connection is removed to obtain the broadband equivalent circuit of the toroidal air-core reactor.

4. The method for determining the transient voltage distribution of a toroidal air-core reactor according to claim 1, characterized in that, Based on the broadband equivalent circuit, basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters, the voltage distribution during the transient process is calculated, resulting in the transient voltage distribution of the toroidal air-core reactor, specifically including: Get the type of the currently applied stimulus source; Generate a circuit simulation file based on the broadband equivalent circuit and the type of the currently applied excitation source; Based on the circuit simulation file, the transient voltage distribution of the toroidal air-core reactor is calculated; The transient voltage distribution waveform is determined based on the calculation results.

5. A transient voltage distribution determination system for a toroidal air-core reactor, used to implement the transient voltage distribution determination method for a toroidal air-core reactor according to any one of claims 1-4, characterized in that, The transient voltage distribution determination system for the toroidal air-core reactor includes: an input / output unit, a reactor parameter storage unit, a parameter extraction unit, a circuit parameter storage unit, a broadband equivalent circuit construction unit, and a transient voltage distribution determination unit; The input / output unit is used to input the basic parameters of the toroidal air-core reactor and to display the calculation results; The reactor parameter storage unit is used to store the basic parameters of the toroidal air-core reactor. The parameter extraction unit is used to extract circuit parameters using the basic parameters to obtain resistance parameters, inductance parameters, and parasitic capacitance parameters. The circuit parameter storage unit is used to store resistance parameters, inductance parameters, and parasitic capacitance parameters; The broadband equivalent circuit construction unit is used to construct a broadband equivalent circuit based on the basic parameters stored in the reactor parameter storage unit and the resistance, inductance and parasitic capacitance parameters stored in the circuit parameter storage unit. The transient voltage distribution determination unit is used to calculate the voltage distribution during the transient process based on the broadband equivalent circuit, basic parameters, resistance parameters, inductance parameters, and parasitic capacitance parameters.

6. The transient voltage distribution determination system for a toroidal air-core reactor according to claim 5, characterized in that, The input / output unit includes: an input panel, an input display, an output display, and an external storage device.

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