Arrester configuration scheme determination method of bridge arm reactor and related equipment

Abstract

The invention discloses a method for determining a lightning arrester configuration scheme of a bridge arm reactor and related equipment, and the method comprises the steps: taking the total equivalent impedance of a pre-configured lightning arrester module as a variable, taking the condition that the fault current of the pre-configured lightning arrester module is smaller than the maximum short-circuit current as a constraint, and constructing a first equivalent impedance constraint function; constructing a second equivalent impedance constraint function by taking the condition that the protection level of the pre-configured lightning arrester module is not greater than the end-to-end insulation voltage upper limit of the bridge arm reactor as a constraint and taking the total column number, the total equivalent impedance and the curve fitting factor of the pre-configured lightning arrester module as variables; generating a feasible solution based on volt-ampere characteristic fitting coefficients of different lightning arrester valve plate types; and selecting an optimal feasible solution from the feasible solutions as a lightning arrester configuration scheme of the target MMC. It can be seen that through the technical process of double-constraint function construction, step-by-step solution, feasible solution screening and optimal solution determination, the calculation efficiency is higher, and standardization and replicability are better achieved.

Description

Technical Field

[0001] This application relates to the field of modular multilevel flexible DC system technology, and more specifically, to a method for determining the surge arrester configuration scheme of a bridge arm reactor and related equipment. Background Technology

[0002] Currently, Modular Multilevel Flexible DC Systems (MMCs) have become a preferred topology for large-scale, ultra-long-distance transmission of new energy. MMCs typically incorporate arm reactors, whose main function is to limit circulating current in the arm and, in the event of a system fault, to limit fault current.

[0003] Because the turn-off process of an Insulated Gate Bipolar Transistor (IGBT) is extremely short, its rapid turn-off characteristic easily leads to high overvoltages, which are particularly pronounced across the bridge arm reactor. Therefore, surge arresters are typically installed across the bridge arm reactor in engineering to effectively suppress overvoltage levels. However, when surge arresters are installed across the reactor, the large current flowing through them after a fault occurs significantly reduces the reactor's ability to limit short-circuit current. Therefore, surge arrester parameter design is an indispensable part of the MMC configuration process.

[0004] In existing technologies, electromagnetic transient simulation is usually used to determine the final surge arrester parameters through multiple iterative calculations. However, the above method is not only cumbersome in its iterative calculation process, but also has a large workload, making it difficult to quickly select surge arrester parameters and failing to meet the efficiency requirements of engineering design. Summary of the Invention

[0005] In view of this, this application provides a method and related equipment for determining the surge arrester configuration scheme of a bridge arm reactor, which is used to solve the disadvantage of low speed in the existing surge arrester parameter design scheme.

[0006] To achieve the above objectives, the following solution is proposed:

[0007] A method for determining the surge arrester configuration scheme of a bridge arm reactor includes:

[0008] Using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, a first equivalent impedance constraint function is constructed.

[0009] With the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables, a second equivalent impedance constraint function is constructed.

[0010] Solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values;

[0011] Based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types, all feasible solutions of the second equivalent impedance constraint function are generated.

[0012] The optimal feasible solution is selected from all feasible solutions as the surge arrester configuration scheme for the target MMC.

[0013] Optionally, the first equivalent impedance constraint function is constructed using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current. This function includes:

[0014] Based on the equivalent impedance of the transformer in the target MMC, the reactance value of the bridge arm reactor, and the peak value of the AC side fault voltage, a first current calculation function is constructed using the total equivalent impedance as a variable to calculate the peak value of the AC side fault current.

[0015] Based on the module capacitance value, number of capacitors, and DC voltage of the target MMC, a second current calculation function is generated for calculating the DC capacitor fault current.

[0016] Based on the first current calculation function and the second current calculation function, a first equivalent impedance constraint function is constructed with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current.

[0017] Optionally, the first equivalent impedance constraint function is constructed based on the first current calculation function and the second current calculation function, with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, including:

[0018] By integrating the first current calculation function and the second current calculation function, a peak fault current calculation expression is generated for the surge arrester module pre-configured in the target MMC;

[0019] The first equivalent impedance constraint function is calculated based on the fact that the peak fault current is not greater than the product of the maximum turn-off current of the insulated gate bipolar transistor (IGBT) and the margin factor.

[0020] Optionally, the first equivalent impedance constraint function is:

[0021]

[0022] In the formula, This represents the peak value of the AC side fault voltage. Angular frequency; As the first intermediate variable; It is the second intermediate variable; This refers to the module capacitance value. This refers to the number of capacitors. The reactance value of the bridge arm reactor; The equivalent impedance of the transformer; It is a DC voltage; This is the margin coefficient; This is the maximum turn-off current of the IGBT; This is the total equivalent impedance.

[0023] Optionally, the second equivalent impedance constraint function is constructed, with the constraint that the protection level of the pre-configured surge arrester module is not greater than the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables. This function includes:

[0024] Based on the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor, a calculation expression for the protection level of the pre-configured surge arrester module is generated.

[0025] The second equivalent impedance constraint function is calculated based on the protection level, and the expression is not greater than the upper limit of the inter-terminal insulation voltage of the bridge arm reactor.

[0026] Optionally, the second equivalent impedance constraint function is:

[0027]

[0028] In the formula, This is the total equivalent impedance; The total number of columns; q is the preset ratio; q is the curve fitting factor; This is the upper limit of the inter-terminal insulation voltage.

[0029] Optionally, the step of generating all feasible solutions to the second equivalent impedance constraint function based on the equivalent impedance range and the fitting coefficients of the volt-ampere characteristics for different surge arrester valve types includes:

[0030] The volt-ampere characteristic fitting coefficient of each arrester valve type is successively substituted into the second equivalent impedance constraint function as the curve fitting factor to determine all feasible values ​​of the number of columns that satisfy the equivalent impedance value range and belong to positive integers.

[0031] A feasible solution is formed by combining the arrester valve type corresponding to each volt-ampere characteristic fitting coefficient and one of its corresponding column number feasible values.

[0032] A device for determining the surge arrester configuration scheme of a bridge arm reactor, comprising:

[0033] A construction module is used to construct a first equivalent impedance constraint function with the total equivalent impedance of the pre-configured surge arrester module as a variable and the fault current flowing through the pre-configured surge arrester module in the target MMC being less than the maximum short-circuit current as a constraint.

[0034] The constraint module is used to construct a second equivalent impedance constraint function with the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance and the curve fitting factor as variables.

[0035] The solution module is used to solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values;

[0036] The generation module is used to generate all feasible solutions to the second equivalent impedance constraint function based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types.

[0037] The selection module is used to select the optimal feasible solution from all feasible solutions as the surge arrester configuration scheme for the target MMC.

[0038] A device for determining the surge arrester configuration scheme of a bridge arm reactor includes a memory and a processor;

[0039] The memory is used to store programs;

[0040] The processor is used to execute the program to implement each step of the above-described method for determining the surge arrester configuration scheme of the bridge arm reactor.

[0041] A readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the various steps of the above-described method for determining the surge arrester configuration scheme of the bridge arm reactor.

[0042] As can be seen from the above technical solution, the method for determining the surge arrester configuration scheme of the bridge arm reactor provided in this application includes constructing a first equivalent impedance constraint function with the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current. Based on this, this application can link the total equivalent impedance of the surge arrester with the hard index of system fault current suppression, so that the surge arrester parameters in the configuration scheme can be correlated with the overcurrent suppression capability. Matching the surge arrester configuration to avoid weakening the current-limiting capability of the bridge arm reactor, ensuring that the surge arrester configuration does not affect the basic performance of the system's fault current-limiting capability; this application constructs a second equivalent impedance constraint function by using the constraint that the protection level of the pre-configured surge arrester module is not greater than the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor, and using the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables; this can achieve the goal of starting from the core requirements of overvoltage protection, connecting with the insulation withstand limit of the bridge arm reactor, and ensuring that the protection capability of the surge arrester is consistent with the core requirements of overvoltage protection. The insulation characteristics of the protected equipment are matched to avoid overvoltage breakdown of the reactor insulation. Surge arrester configuration parameters (total number of columns) and volt-ampere characteristic fitting parameters (curve fitting factors) are introduced as variables to correlate the electrical and structural parameters of the surge arrester. This allows the constraint function to simultaneously cover the actual needs of both equipment characteristics and engineering configuration, enabling subsequent solution results to directly adapt to the actual engineering configuration scenario without additional structural parameter conversion. Subsequently, this application can solve the first equivalent impedance constraint function to obtain the equivalent impedance value range. Based on the equivalent impedance value range and the volt-ampere characteristic fitting coefficients for different surge arrester valve types, all feasible solutions to the second equivalent impedance constraint function are generated. Therefore, this application can adopt a step-by-step solution strategy, first determining the basic impedance range under a single current-limiting constraint, breaking down the complex solution of multiple constraints into a simple solution of a single constraint, improving computational efficiency. The volt-ampere characteristic fitting coefficients for different valve types can be introduced to achieve the universality and flexibility of the solution. Finally, this application completes the determination of the surge arrester configuration scheme by selecting the optimal feasible solution from all feasible solutions as the surge arrester configuration scheme for the target MMC. As can be seen, this application can transform the process of determining the surge arrester configuration scheme into a process of constructing and solving dual constraint functions through a technical process of constructing dual constraint functions, solving step by step, screening feasible solutions, and determining the optimal solution. Compared with simulation iterative calculation, this method has higher computational efficiency and is more standardized and reproducible. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0044] Figure 1 This is a flowchart of a method for determining the surge arrester configuration scheme of a bridge arm reactor disclosed in an embodiment of this application;

[0045] Figure 2 This is a structural block diagram of a surge arrester configuration scheme determination device for a bridge arm reactor disclosed in an embodiment of this application;

[0046] Figure 3 This is a hardware structure block diagram of a surge arrester configuration scheme determination device for a bridge arm reactor disclosed in an embodiment of this application. Detailed Implementation

[0047] 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.

[0048] This application provides a method for determining the surge arrester configuration scheme of a bridge arm reactor. This method can be applied to various MMC configuration systems or power grid parameter management systems, as well as to various computer terminals or smart terminals. The executing entity can be the processor or server of the computer terminal or smart terminal.

[0049] Next, combine Figure 1 The method for determining the surge arrester configuration scheme of the bridge arm reactor in this application is described in detail, including the following steps:

[0050] Step S1: Using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, construct the first equivalent impedance constraint function.

[0051] Specifically, the equivalent impedance of the transformer in the target MMC, the reactance value of the bridge arm reactor, the peak value of the AC side fault voltage, the module capacitance value, the number of capacitors and the DC voltage can be combined, and the total equivalent impedance of the pre-configured surge arrester module can be used as a variable to construct a first equivalent impedance constraint function with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum value of the short-circuit current.

[0052] Step S2: With the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables, construct a second equivalent impedance constraint function.

[0053] Specifically, based on the total number of columns, total equivalent impedance, and curve fitting factor of the pre-configured surge arrester module, the protection level calculation expression of the pre-configured surge arrester module can be derived, and the result of the expression can be ensured to not exceed the upper limit of the inter-terminal insulation voltage of the bridge arm reactor, thereby constructing the second equivalent impedance constraint function.

[0054] Step S3: Solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values.

[0055] Specifically, the range of values ​​for the total equivalent impedance that satisfies the condition that the fault current is less than the maximum value of the short-circuit current can be obtained by performing mathematical analysis or numerical calculation on the first equivalent impedance constraint function.

[0056] Step S4: Based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types, generate all feasible solutions for the second equivalent impedance constraint function.

[0057] Specifically, by combining the fitting coefficients of each type of current-voltage characteristic and the range of equivalent impedance values, the second equivalent impedance constraint function can be solved to generate all feasible solutions.

[0058] Step S5: Select the optimal feasible solution from all feasible solutions as the surge arrester configuration scheme for the target MMC.

[0059] Specifically, based on the actual needs of the project, such as cost, configuration space, and maintenance convenience, the optimal feasible solution can be selected from all feasible solutions. This optimal feasible solution is the surge arrester configuration scheme for the target MMC. This scheme can meet the requirements of system fault current limiting and overvoltage protection while adapting to the actual engineering situation to the greatest extent.

[0060] As can be seen from the above technical solution, the method for determining the surge arrester configuration scheme of the bridge arm reactor provided in this application includes constructing a first equivalent impedance constraint function with the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current. Based on this, this application can link the total equivalent impedance of the surge arrester with the hard index of system fault current suppression, so that the surge arrester parameters in the configuration scheme can be correlated with the overcurrent suppression capability. Matching the surge arrester configuration to avoid weakening the current-limiting capability of the bridge arm reactor, ensuring that the surge arrester configuration does not affect the basic performance of the system's fault current-limiting capability; this application constructs a second equivalent impedance constraint function by using the constraint that the protection level of the pre-configured surge arrester module is not greater than the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor, and using the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables; this can achieve the goal of starting from the core requirements of overvoltage protection, connecting with the insulation withstand limit of the bridge arm reactor, and ensuring that the protection capability of the surge arrester is consistent with the core requirements of overvoltage protection. The insulation characteristics of the protected equipment are matched to avoid overvoltage breakdown of the reactor insulation. Surge arrester configuration parameters (total number of columns) and volt-ampere characteristic fitting parameters (curve fitting factors) are introduced as variables to correlate the electrical and structural parameters of the surge arrester. This allows the constraint function to simultaneously cover the actual needs of both equipment characteristics and engineering configuration, enabling subsequent solution results to directly adapt to the actual engineering configuration scenario without additional structural parameter conversion. Subsequently, this application can solve the first equivalent impedance constraint function to obtain the equivalent impedance value range. Based on the equivalent impedance value range and the volt-ampere characteristic fitting coefficients for different surge arrester valve types, all feasible solutions to the second equivalent impedance constraint function are generated. Therefore, this application can adopt a step-by-step solution strategy, first determining the basic impedance range under a single current-limiting constraint, breaking down the complex solution of multiple constraints into a simple solution of a single constraint, improving computational efficiency. The volt-ampere characteristic fitting coefficients for different valve types can be introduced to achieve the universality and flexibility of the solution. Finally, this application completes the determination of the surge arrester configuration scheme by selecting the optimal feasible solution from all feasible solutions as the surge arrester configuration scheme for the target MMC. As can be seen, this application can transform the process of determining the surge arrester configuration scheme into a process of constructing and solving dual constraint functions through a technical process of constructing dual constraint functions, solving step by step, screening feasible solutions, and determining the optimal solution. Compared with simulation iterative calculation, this method has higher computational efficiency and is more standardized and reproducible.

[0061] In some embodiments of this application, the process of constructing the first equivalent impedance constraint function in step S1, using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, is described in detail below:

[0062] S10. Based on the equivalent impedance of the transformer in the target MMC, the reactance value of the bridge arm reactor, and the peak value of the AC side fault voltage, a first current calculation function is constructed using the total equivalent impedance as a variable to calculate the peak value of the AC side fault current.

[0063] Specifically, the first current calculation function can be as follows:

[0064]

[0065]

[0066] In the formula, This can be the peak value of the AC side fault current; This could be the peak value of the AC side fault voltage; It can be angular frequency; It can be the first intermediate variable; It can be a second intermediate variable; It can be the reactance value of the bridge arm reactor; It can be the equivalent impedance of a transformer; It can be the total equivalent impedance.

[0067] S11. Based on the module capacitance value, number of capacitors and DC voltage of the target MMC, generate a second current calculation function for calculating the DC capacitor fault current.

[0068] Specifically, the function for calculating the second current can be as follows:

[0069]

[0070] In the formula, This can be the fault current of a DC capacitor; This refers to the module capacitance value. This refers to the number of capacitors. It is a DC voltage.

[0071] It should be noted that the first current calculation function in this application is used to calculate the peak value of the AC side fault current; the second current calculation function is used to calculate the DC capacitor fault current.

[0072] S12. Based on the first current calculation function and the second current calculation function, and with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, a first equivalent impedance constraint function is constructed.

[0073] Specifically, the first current calculation function and the second current calculation function can be superimposed to generate the peak fault current calculation expression, and the first equivalent impedance constraint function can be formed by constraining the peak fault current calculation expression to be less than the maximum short-circuit current.

[0074] As can be seen from the above technical solution, this embodiment provides an optional method for constructing a first equivalent impedance constraint function, using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current. Through this method, multiple factors can be comprehensively considered, including the transformer equivalent impedance in the target MMC, the reactance value of the bridge arm reactor, the peak AC fault voltage, the module capacitance value, the number of capacitors, and the DC voltage. This ensures that the constructed constraint function accurately reflects the actual system situation, guarantees that the surge arrester parameters match the overcurrent suppression capability, effectively avoids the problem of weakened current-limiting capability of the bridge arm reactor after surge arrester configuration, and ensures that the basic performance of the system's fault current limiting is not affected.

[0075] At the same time, this construction method has strong versatility and flexibility, and can be adjusted and optimized according to the specific parameters of different MMC configuration systems to meet diverse engineering needs.

[0076] In some embodiments of this application, the process of constructing the first equivalent impedance constraint function based on the first current calculation function and the second current calculation function, with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, is described in detail below:

[0077] S120. Integrate the first current calculation function and the second current calculation function to generate a calculation expression for the peak fault current flowing through the pre-configured surge arrester module in the target MMC.

[0078] Specifically, although there may be a phase deviation between the peak AC fault current and the DC capacitor fault current, in order to improve the calculation margin, the peak AC fault current and the DC capacitor fault current can be directly added together to obtain the calculation expression for the peak fault current.

[0079] In scenarios requiring high accuracy, the peak value of the AC fault current can be vector-added with the DC capacitor fault current to obtain the expression for calculating the peak value of the fault current.

[0080] According to actual needs, a matching addition method can be used to form a calculation expression for the peak fault current.

[0081] S121. The first equivalent impedance constraint function is calculated using the peak fault current expression, which is not greater than the product of the maximum turn-off current of the insulated gate bipolar transistor (IGBT) and the margin coefficient.

[0082] Specifically, the maximum turn-off current of the Insulated Gate Bipolar Transistor (IGBT), a commonly used switching device in the field of power electronics, is an important indicator for measuring its ability to withstand overcurrent.

[0083] The margin factor can be determined based on the uncertainties and safety considerations in actual engineering projects.

[0084] Generally speaking, the value can be 0.9.

[0085] As can be seen from the above technical solution, this embodiment provides an optional method for constructing a first equivalent impedance constraint function based on the first current calculation function and the second current calculation function, with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current. Through this method, the safety and stability of the system are enhanced by introducing a margin coefficient, achieving the best protection effect.

[0086] Furthermore, the first equivalent impedance constraint function can be defined as follows:

[0087]

[0088] In the formula, This represents the peak value of the AC side fault voltage. Angular frequency; As the first intermediate variable; It is the second intermediate variable; This refers to the module capacitance value. This refers to the number of capacitors. The reactance value of the bridge arm reactor; The equivalent impedance of the transformer; It is a DC voltage; This is the margin coefficient; This is the maximum turn-off current of the IGBT; This is the total equivalent impedance.

[0089] In some embodiments of this application, the process of constructing a second equivalent impedance constraint function in step S2, which is constrained by the protection level of the pre-configured surge arrester module not being greater than the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor, and using the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables, is described in detail below:

[0090] S20. Based on the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor, generate a calculation expression for the protection level of the pre-configured surge arrester module.

[0091] Specifically, it can be Set as the ratio of the protection level of the pre-configured surge arrester module to the reference voltage.

[0092] The protection level calculation expression of the pre-configured surge arrester module can be generated by combining the surge arrester curve, based on the ratio, the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor.

[0093] S21. The second equivalent impedance constraint function is calculated based on the protection level and the expression is not greater than the upper limit of the inter-terminal insulation voltage of the bridge arm reactor.

[0094] Specifically, the protection level calculation expression of the pre-configured surge arrester module can be compared with the upper limit of the inter-terminal insulation voltage of the bridge arm reactor, and an inequality relationship can be constructed. This inequality is the second equivalent impedance constraint function.

[0095] As can be seen from the above technical solution, this embodiment provides an optional method for constructing a second equivalent impedance constraint function, with the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables. This method ensures that the protection level of the surge arrester will not exceed the insulation withstand limit of the bridge arm reactor, thereby guaranteeing the safe operation of the system. Starting from the core requirements of overvoltage protection, it precisely connects the insulation withstand characteristics of the bridge arm reactor, ensuring that the protection capability of the surge arrester matches the insulation characteristics of the protected equipment, effectively improving the matching degree between the surge arrester parameter selection and overvoltage requirements.

[0096] Furthermore, the second equivalent impedance constraint function can be as follows:

[0097]

[0098] In the formula, It can be the total equivalent impedance; This can be the total number of columns; The value can be a preset ratio; q can be a curve fitting factor. It can be the upper limit of the inter-terminal insulation voltage.

[0099] The upper limit of the inter-terminal insulation voltage can be the insulation design value of the corresponding bridge arm reactor, or it can be the value obtained after introducing a margin value into the insulation design value.

[0100] In some embodiments of this application, the process of generating all feasible solutions to the second equivalent impedance constraint function based on the equivalent impedance value range and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types is described in detail below:

[0101] S40. Substitute the fitting coefficient of the volt-ampere characteristic of each arrester valve type into the second equivalent impedance constraint function as the curve fitting factor to determine all feasible values ​​of the number of columns that satisfy the equivalent impedance value range and belong to positive integers.

[0102] Specifically, since the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types are different, after substituting them into the second equivalent impedance constraint function in sequence, and combining the equivalent impedance value range, through mathematical calculation and screening, all possible values ​​of positive integer column numbers that make the total equivalent impedance satisfy the equivalent impedance value range can be obtained.

[0103] For example, for a specific type of surge arrester varistor, its volt-ampere characteristic fitting coefficient is a specific value. After substituting it into the second equivalent impedance constraint function, and combining it with the obtained equivalent impedance value range, the feasible value of the number of columns that is a positive integer and makes the total equivalent impedance fall within the value range can be selected by solving inequalities and other methods.

[0104] Each feasible value for the number of columns reflects the possible values ​​for the total number of columns in the pre-configured surge arrester module under different valve plate types.

[0105] S41. Combine the arrester valve type corresponding to each volt-ampere characteristic fitting coefficient and one of its corresponding column number feasible values ​​to form a feasible solution.

[0106] Specifically, for each volt-ampere characteristic fitting coefficient, a feasible value of the corresponding column number that meets the conditions is selected, which together with the surge arrester valve type to which the coefficient belongs constitutes a complete feasible solution.

[0107] Each feasible solution may include the surge arrester valve type and the total number of valves; it may also include key information such as the total equivalent impedance determined therefrom.

[0108] As can be seen from the above technical solution, this embodiment provides an optional method for generating all feasible solutions to the second equivalent impedance constraint function based on the equivalent impedance range and the volt-ampere characteristic fitting coefficients for different surge arrester valve types. This method fully considers the characteristic differences of different surge arrester valve types, combines the volt-ampere characteristic fitting coefficients with the equivalent impedance range, and comprehensively and systematically generates all feasible solutions, ensuring that the final determined surge arrester configuration scheme can adapt to diverse engineering needs. At the same time, this method has strong operability and practicality, and can effectively improve the efficiency and quality of scheme determination.

[0109] Next, we will combine Figure 2 The surge arrester configuration scheme determination device for bridge arm reactors provided in this application is described in detail. The surge arrester configuration scheme determination device for bridge arm reactors provided below can be compared with the surge arrester configuration scheme determination method for bridge arm reactors provided above.

[0110] See Figure 2 It can be observed that the device for determining the surge arrester configuration scheme of the bridge arm reactor may include:

[0111] Module 10 is used to construct a first equivalent impedance constraint function with the total equivalent impedance of the pre-configured surge arrester module as a variable and the fault current flowing through the pre-configured surge arrester module in the target MMC being less than the maximum short-circuit current as a constraint.

[0112] The constraint module 20 is used to construct a second equivalent impedance constraint function with the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance and the curve fitting factor as variables.

[0113] The solver module 30 is used to solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values;

[0114] The generation module 40 is used to generate all feasible solutions of the second equivalent impedance constraint function based on the equivalent impedance value range and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types.

[0115] The selection module 50 is used to select the optimal feasible solution from all feasible solutions as the surge arrester configuration scheme for the target MMC.

[0116] Furthermore, the building module 10 may include:

[0117] The first current calculation function construction unit is used to construct a first current calculation function for calculating the peak value of the AC side fault current based on the equivalent impedance of the transformer in the target MMC, the reactance value of the bridge arm reactor and the peak value of the AC side fault voltage, with the total equivalent impedance as the variable.

[0118] The second current calculation function construction unit is used to generate a second current calculation function for calculating the DC capacitor fault current based on the module capacitance value, number of capacitors and DC voltage of the target MMC.

[0119] The first equivalent impedance constraint function construction unit is used to construct the first equivalent impedance constraint function based on the first current calculation function and the second current calculation function, with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current.

[0120] Furthermore, the first current calculation function construction unit may include:

[0121] The calculation expression generation subunit is used to integrate the first current calculation function and the second current calculation function to generate a calculation expression for the peak fault current flowing through the pre-configured surge arrester module in the target MMC;

[0122] The calculation expression constraint subunit is used to calculate the first equivalent impedance constraint function with the peak fault current calculated as not being greater than the product of the maximum turn-off current of the insulated gate bipolar transistor (IGBT) and the margin coefficient.

[0123] Furthermore, the computation expression constraint sub-unit may include:

[0124] A function storage component is used to store the first equivalent impedance constraint function;

[0125] The first equivalent impedance constraint function is:

[0126]

[0127] In the formula, This represents the peak value of the AC side fault voltage. Angular frequency; As the first intermediate variable; It is the second intermediate variable; This refers to the module capacitance value. This refers to the number of capacitors. The reactance value of the bridge arm reactor; The equivalent impedance of the transformer; It is a DC voltage; This is the margin coefficient; This is the maximum turn-off current of the IGBT; This is the total equivalent impedance.

[0128] Furthermore, the constraint module 20 may include:

[0129] The protection level calculation expression generation unit is used to generate the protection level calculation expression of the pre-configured surge arrester module based on the total number of columns, the total equivalent impedance, and the curve fitting factor of the pre-configured surge arrester module.

[0130] The second equivalent impedance constraint function construction unit is used to calculate the second equivalent impedance constraint function with the expression of the protection level not being greater than the upper limit of the inter-terminal insulation voltage of the bridge arm reactor.

[0131] Furthermore, the second equivalent impedance constraint function building block may include:

[0132] The constraint function storage sub-cell is used to store the second equivalent impedance constraint function;

[0133] The second equivalent impedance constraint function is:

[0134]

[0135] In the formula, This is the total equivalent impedance; The total number of columns; q is the preset ratio; q is the curve fitting factor; This is the upper limit of the inter-terminal insulation voltage.

[0136] The surge arrester configuration scheme determination device for bridge arm reactors provided in this application embodiment can be applied to surge arrester configuration scheme determination equipment for bridge arm reactors, such as PC terminals, cloud platforms, servers, and server clusters. Optionally, Figure 3 The diagram shows the hardware structure of the equipment for determining the surge arrester configuration scheme of the bridge arm reactor. (Refer to...) Figure 3 The configuration scheme of the surge arrester of the bridge arm reactor determines that the hardware structure of the equipment may include: at least one processor 1, at least one communication interface 2, at least one memory 3 and at least one communication bus 4;

[0137] In this embodiment, the number of processor 1, communication interface 2, memory 3, and communication bus 4 is at least one, and processor 1, communication interface 2, and memory 3 communicate with each other through communication bus 4.

[0138] Processor 1 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0139] Memory 3 may include high-speed RAM, and may also include non-volatile memory, such as at least one disk storage device;

[0140] The memory stores a program, which the processor can call. The program is used for:

[0141] Using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, a first equivalent impedance constraint function is constructed.

[0142] With the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables, a second equivalent impedance constraint function is constructed.

[0143] Solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values;

[0144] Based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types, all feasible solutions of the second equivalent impedance constraint function are generated.

[0145] The optimal feasible solution is selected from all feasible solutions as the surge arrester configuration scheme for the target MMC.

[0146] Optionally, the refined and extended functions of the program can be referred to the above description.

[0147] This application embodiment also provides a readable storage medium that can store a program suitable for execution by a processor, the program being used for:

[0148] Using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, a first equivalent impedance constraint function is constructed.

[0149] With the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables, a second equivalent impedance constraint function is constructed.

[0150] Solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values;

[0151] Based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types, all feasible solutions of the second equivalent impedance constraint function are generated.

[0152] The optimal feasible solution is selected from all feasible solutions as the surge arrester configuration scheme for the target MMC.

[0153] Optionally, the refined and extended functions of the program can be referred to the above description.

[0154] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0155] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0156] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. The various embodiments of this application can be combined with each other. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the surge arrester configuration scheme of a bridge arm reactor, characterized in that, include: Using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, a first equivalent impedance constraint function is constructed. With the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables, a second equivalent impedance constraint function is constructed. Solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values; Based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types, all feasible solutions of the second equivalent impedance constraint function are generated. The optimal feasible solution is selected from all feasible solutions as the surge arrester configuration scheme for the target MMC.

2. The method for determining the surge arrester configuration scheme of the bridge arm reactor according to claim 1, characterized in that, The first equivalent impedance constraint function is constructed using the total equivalent impedance of the pre-configured surge arrester module as a variable and the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current. This function includes: Based on the equivalent impedance of the transformer in the target MMC, the reactance value of the bridge arm reactor, and the peak value of the AC side fault voltage, a first current calculation function is constructed using the total equivalent impedance as a variable to calculate the peak value of the AC side fault current. Based on the module capacitance value, number of capacitors, and DC voltage of the target MMC, a second current calculation function is generated for calculating the DC capacitor fault current. Based on the first current calculation function and the second current calculation function, a first equivalent impedance constraint function is constructed with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current.

3. The method for determining the surge arrester configuration scheme of the bridge arm reactor according to claim 2, characterized in that, Based on the first current calculation function and the second current calculation function, and with the constraint that the fault current flowing through the pre-configured surge arrester module in the target MMC is less than the maximum short-circuit current, a first equivalent impedance constraint function is constructed, including: By integrating the first current calculation function and the second current calculation function, a peak fault current calculation expression is generated for the surge arrester module pre-configured in the target MMC; The first equivalent impedance constraint function is calculated based on the fact that the peak fault current is not greater than the product of the maximum turn-off current of the insulated gate bipolar transistor (IGBT) and the margin factor.

4. The method for determining the surge arrester configuration scheme of the bridge arm reactor according to claim 3, characterized in that, The first equivalent impedance constraint function is: In the formula, This represents the peak value of the AC side fault voltage. Angular frequency; As the first intermediate variable; It is the second intermediate variable; This refers to the module capacitance value. This refers to the number of capacitors. The reactance value of the bridge arm reactor; The equivalent impedance of the transformer; It is a DC voltage; This is the margin coefficient; This is the maximum turn-off current of the IGBT; This is the total equivalent impedance.

5. The method for determining the surge arrester configuration scheme of the bridge arm reactor according to claim 1, characterized in that, The second equivalent impedance constraint function is constructed, with the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor as variables. This function includes: Based on the total number of columns of the pre-configured surge arrester module, the total equivalent impedance, and the curve fitting factor, a calculation expression for the protection level of the pre-configured surge arrester module is generated. The second equivalent impedance constraint function is calculated based on the protection level, and the expression is not greater than the upper limit of the inter-terminal insulation voltage of the bridge arm reactor.

6. The method for determining the surge arrester configuration scheme of the bridge arm reactor according to claim 5, characterized in that, The second equivalent impedance constraint function is: In the formula, This is the total equivalent impedance; The total number of columns; q is the preset ratio; q is the curve fitting factor; This is the upper limit of the inter-terminal insulation voltage.

7. The method for determining the surge arrester configuration scheme of the bridge arm reactor according to claim 1, characterized in that, Based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics for different surge arrester valve types, all feasible solutions to the second equivalent impedance constraint function are generated, including: The volt-ampere characteristic fitting coefficient of each arrester valve type is successively substituted into the second equivalent impedance constraint function as the curve fitting factor to determine all feasible values ​​of the number of columns that satisfy the equivalent impedance value range and belong to positive integers. A feasible solution is formed by combining the arrester valve type corresponding to each volt-ampere characteristic fitting coefficient and one of its corresponding column number feasible values.

8. A device for determining the surge arrester configuration scheme of a bridge arm reactor, characterized in that, include: A construction module is used to construct a first equivalent impedance constraint function with the total equivalent impedance of the pre-configured surge arrester module as a variable and the fault current flowing through the pre-configured surge arrester module in the target MMC being less than the maximum short-circuit current as a constraint. The constraint module is used to construct a second equivalent impedance constraint function with the protection level of the pre-configured surge arrester module not exceeding the upper limit of the inter-terminal insulation voltage of its corresponding bridge arm reactor as a constraint, and with the total number of columns of the pre-configured surge arrester module, the total equivalent impedance and the curve fitting factor as variables. The solution module is used to solve the first equivalent impedance constraint function to obtain the range of equivalent impedance values; The generation module is used to generate all feasible solutions to the second equivalent impedance constraint function based on the range of equivalent impedance values ​​and the fitting coefficients of the volt-ampere characteristics of different surge arrester valve types. The selection module is used to select the optimal feasible solution from all feasible solutions as the surge arrester configuration scheme for the target MMC.

9. A device for determining the surge arrester configuration scheme of a bridge arm reactor, characterized in that, Including memory and processor; The memory is used to store programs; The processor is used to execute the program to implement each step of the method for determining the surge arrester configuration scheme of the bridge arm reactor as described in any one of claims 1-7.

10. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements each step of the method for determining the surge arrester configuration scheme of the bridge arm reactor as described in any one of claims 1-7.

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