A method and system for obtaining inductance value of a current limiting reactor

Abstract

This invention discloses a method and system for obtaining the inductance value of a current-limiting reactor, belonging to the field of flexible DC transmission technology. The method comprises: obtaining a candidate inductance sequence for the current-limiting reactor to be selected; performing fault and dynamic response simulations on each candidate inductor to obtain a comprehensive safety index score and a comprehensive dynamic performance index score, thereby constructing several initial mapping models; fitting these models to obtain several performance mapping models; constructing several utopian lines based on these models and obtaining several candidate solution points, thereby calculating the relative proximity of these candidate solution points; determining several comprehensive performance points based on preset selection conditions and the relative proximity, and using reverse indexing based on these comprehensive performance points and the performance mapping models to obtain candidate setting inductance values. The method for obtaining the inductance value of a current-limiting reactor provided by this invention enables a balanced selection of reactor parameters between fault safety and dynamic adjustability.

Description

Technical Field

[0001] This invention relates to the field of parameter setting technology for line current-limiting reactors, and in particular to a method and system for obtaining the inductance value of a current-limiting reactor. Background Technology

[0002] Flexible DC transmission technology has become a core technology for constructing multi-terminal DC grids and large-scale renewable energy aggregation systems due to its advantages of being able to supply power to passive networks, eliminating the risk of commutation failure, and independently controlling active and reactive power. Currently, most mainstream flexible DC converter stations adopt modular multilevel converter (MMC) topologies. However, due to the extremely low impedance and lack of natural zero-crossing points in DC grids, once an inter-pole short circuit or single-pole ground fault occurs, the discharge current of the MMC submodule capacitor will rapidly increase to several times or even tens of times its rated value within milliseconds. Even if the converter valve is locked, the AC grid will still continuously inject energy into the fault point through an uncontrolled rectifier circuit formed by reverse-parallel diodes. To limit the rate of rise of the fault current and ensure that the DC circuit breaker can operate reliably within its breaking capacity, line current-limiting reactors (or smoothing reactors) are usually configured at both ends of the DC line in engineering practice.

[0003] In the current technological context, the inductance value of traditional current-limiting reactors is primarily determined by safety principles. Engineers typically use a simplified RLC circuit model to deduce the minimum required inductance value based on the DC circuit breaker's breaking current limit, the operating time of the protection device, and the most severe fault conditions. However, while this method ensures equipment safety under fault conditions, it often results in excessively high inductance values ​​due to overly large design margins. Furthermore, as the requirements for dynamic power regulation performance in multi-terminal flexible DC power grids become increasingly stringent, the drawbacks of this crude selection method are becoming more apparent: firstly, excessively large inductance values ​​significantly increase the electrical inertia of the DC current loop, causing the power system to respond slower to power step commands or perform power flow reversals, and prolonging rise times; secondly, large inductance can easily reduce the equivalent damping ratio of the power system, or even introduce negative damping effects, leading to significant current overshoot or continuous oscillations when the power system faces disturbances, seriously threatening the dynamic stability of the flexible DC power grid. Summary of the Invention

[0004] The present invention aims to provide a method and system for obtaining the inductance value of a current-limiting reactor, so as to solve the above-mentioned technical problems, avoid the power system stability decline caused by the selection of an excessively high inductance value of the line current-limiting reactor, and achieve a balance between fault safety and dynamic adjustability of the reactor parameters.

[0005] To address the aforementioned technical problems, this invention provides a method for obtaining the inductance value of a current-limiting reactor, comprising: Obtain the candidate inductor sequence for the current-limiting reactor to be selected, and perform fault simulation and dynamic response simulation for each candidate inductor in the candidate inductor sequence to obtain the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors, and construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score. Several initial mapping models are fitted to obtain several first coefficients, several second coefficients and several third coefficients, and several performance mapping models are obtained based on several first coefficients, several second coefficients, several third coefficients and several initial mapping models; Several utopian lines are constructed based on several performance mapping models, and several candidate solution points are obtained based on several utopian lines, so as to calculate several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points. The relative proximity of several candidate solution points is calculated based on several positive ideal solution distances and several negative ideal solution distances. Several comprehensive performance points are determined based on preset selection conditions and several relative proximity. Then, a reverse index is performed based on several comprehensive performance points and several performance mapping models to obtain candidate tuning inductance values.

[0006] In the above scheme, fault simulation and dynamic response simulation are performed for each candidate inductor to obtain the corresponding comprehensive safety index score and dynamic performance comprehensive index score. Then, an initial mapping model is constructed using these scores to correlate candidate inductor values ​​with fault safety performance and dynamic adjustment performance, providing an initial mapping model for subsequent operations. Next, by fitting several initial mapping models, several performance mapping models are obtained, establishing an accurate nonlinear mapping relationship between candidate inductors, fault safety performance, and dynamic adjustment performance. This provides model support for subsequent optimization and balancing of candidate inductor values ​​to obtain candidate setting inductor values. Then, a utopian line is constructed using these performance mapping models. Based on this line, several candidate solution points are obtained, and the corresponding positive and negative ideal solution distances are calculated. This delineates the dual-objective extreme boundary of fault safety performance and dynamic adjustment performance, selecting an inductor parameter range that simultaneously considers both fault safety performance and dynamic adjustment performance. This provides a clear and effective reference range for selecting candidate setting inductor values ​​for the current-limiting reactor. Subsequently, the relative proximity of several candidate solution points is calculated using several positive and several negative ideal solution distances. Then, based on preset selection conditions and the relative proximity, a comprehensive performance point is determined. This allows for the selection of a balance between fault safety performance and dynamic regulation performance among the candidate solution points, resulting in a comprehensive performance point that satisfies both requirements. Finally, candidate setting inductance values ​​are obtained through reverse indexing using several comprehensive performance points and several performance mapping models. This outputs candidate setting inductance values ​​for the current-limiting reactor that balance fault safety performance and dynamic regulation performance, thus avoiding a decrease in power system stability due to excessively high inductance values ​​for the line current-limiting reactor. Ultimately, a balance is achieved between reactor parameters and fault safety and dynamic regulation.

[0007] Further, the process involves obtaining a candidate inductor sequence for the current-limiting reactor to be selected, and performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain a comprehensive safety index score and a comprehensive dynamic performance index score for several candidate inductors. Several initial mapping models are then constructed based on these comprehensive safety index scores and comprehensive dynamic performance index scores, including: Based on the preset inductance value range of the current-limiting reactor to be selected, a sequence of candidate inductors is obtained. For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed respectively to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on the several effective fault transient waveforms and several effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained. Several initial mapping models are constructed based on the scores of several comprehensive security indicators and several comprehensive dynamic performance indicators.

[0008] In the above scheme, a candidate inductor sequence is obtained by using the preset inductance value range of the current-limiting reactor to be selected. This determines the screening range of inductor parameters, providing standardized inductor samples for subsequent selection, avoiding blind simulation without a range, and improving selection efficiency. Next, by conducting fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence, the corresponding effective fault transient waveform and effective step response waveform are obtained. This allows the candidate inductors to be correlated with fault safety performance and dynamic adjustment performance. Furthermore, comprehensive safety index scores and comprehensive dynamic performance index scores, which can be used for modeling, are calculated from the effective fault transient waveform and effective step response waveform, providing a basis for constructing the initial mapping model. Then, several initial mapping models are constructed using several comprehensive safety index scores and several comprehensive dynamic performance index scores, providing an initial model foundation for subsequent model fitting.

[0009] Further, the step involves performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on these effective fault transient waveforms and effective step response waveforms, the step also involves obtaining a comprehensive safety index score and a comprehensive dynamic performance index score for several candidate inductors, including: For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed to obtain several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors. Based on the preset fault time window, the preset step response time window, several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. Based on several valid fault transient waveforms and several valid step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained.

[0010] In the above scheme, by conducting fault simulation and dynamic response simulation for each candidate inductor in the candidate inductor sequence, several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors are obtained. This allows for the collection of full-time current response data for each candidate inductor under different fault conditions and dynamic disturbance conditions, providing raw waveform data for subsequent extraction of effective performance data. Next, by presetting fault time windows, presetting step response time windows, and several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. This allows for the extraction of effective time period data from the full-time waveforms, eliminating invalid waveform information, and providing accurate effective waveforms for subsequent index score calculation. Then, through several effective fault transient waveforms and several effective step response waveforms, performance characteristic indicators can be extracted from the effective waveforms, obtaining comprehensive safety index scores and comprehensive dynamic performance index scores for several candidate inductors that can be directly used for modeling, thus realizing the correlation between candidate inductors and fault safety performance and dynamic adjustment performance.

[0011] Furthermore, the step of obtaining the comprehensive safety index score and the comprehensive dynamic performance index score corresponding to several candidate inductors based on several effective fault transient waveform diagrams and several effective step response waveform diagrams includes: Based on several fault transient waveform diagrams, obtain several initial wavefront equivalent times and several full-segment wavefront apparent times; Based on several initial wavefront equivalent times and several full-segment wavefront apparent times, obtain the initial wavefront index scores and full-segment wavefront index scores for several candidate inductors. Based on several initial wavefront index scores and several full-segment wavefront index scores, obtain the comprehensive safety index scores corresponding to several candidate inductors. Several overshoot values ​​and several rise times are obtained based on several step response waveforms; Based on several overshoot and several rise times, obtain the overshoot index score and the rise time index score of several candidate inductors. The dynamic performance comprehensive index score of several candidate inductors is obtained based on the scores of several overshoot indexes and several rise time indexes.

[0012] In the above scheme, by using several fault transient waveforms, core characteristic quantities representing the rise rate of fault current can be extracted, and several initial wavefront equivalent times and several full-segment wavefront apparent times can be obtained, providing basic time-domain indicators for quantitatively evaluating fault safety performance. Next, by using several initial wavefront equivalent times and several full-segment wavefront apparent times, initial wavefront index scores and full-segment wavefront index scores for several candidate inductors can be obtained, transforming the basic time-domain indicators into a standard scoring format, enabling a unified quantitative comparison of the fault safety performance indicators of different candidate inductors. Then, by using several initial wavefront index scores and several full-segment wavefront index scores, a comprehensive safety index score reflecting the overall fault safety performance of the candidate inductors can be obtained, providing a basis for subsequent modeling. Subsequently, by using several step response waveforms, several overshoot quantities and several rise times that characterize dynamic performance can be extracted, providing basic time-domain indicators for quantitatively evaluating dynamic adjustment performance. Next, by obtaining overshoot and rise time scores for several candidate inductors, the basic dynamic time-domain indicators are transformed into standardized scoring formats, enabling a unified quantitative comparison of the dynamic adjustment performance indicators of different candidate inductors. Finally, by obtaining comprehensive dynamic performance scores for several candidate inductors using the overshoot and rise time scores, a comprehensive dynamic performance score reflecting the overall dynamic adjustment performance of the candidate inductors is obtained, providing a basis for subsequent modeling.

[0013] Furthermore, the acquisition of several initial wavefront equivalent times and several full-segment wavefront apparent times based on several fault transient waveform diagrams includes: Based on the first preset feature point selection condition, feature points are extracted from the transient waveforms of several faults corresponding to several candidate inductors to obtain several first fault feature points and several second fault feature points. Several first fault slope lines are constructed based on several first fault feature points and several second fault feature points, and several initial wavefront equivalent times are obtained based on several first fault slope lines and several fault transient waveform diagrams. Based on the second preset feature point selection conditions, feature points are extracted from several fault transient waveforms corresponding to several candidate inductors to obtain several third fault feature points and several fourth fault feature points. Several second fault slope lines are constructed based on several third fault feature points and several fourth fault feature points, and several full-segment wavefront apparent times are obtained based on several second fault slope lines and several fault transient waveform diagrams.

[0014] In the above scheme, feature points are extracted from several fault transient waveforms corresponding to several candidate inductors using the first preset feature point selection criteria. This allows for precise location of key feature positions during the rising phase of the fault current, obtaining several first fault feature points and several second fault feature points. This provides a basis for subsequently constructing the first fault slope line and calculating the equivalent time of the initial wavefront. Next, several first fault slope lines are constructed using the first and second fault feature points. Based on these first fault slope lines and several fault transient waveforms, several initial wavefront equivalent times are obtained, quantifying the rate characteristics of the initial rise of the fault current and obtaining time-domain indicators characterizing fault safety performance. Then, feature points are extracted from several fault transient waveforms corresponding to several candidate inductors using the second preset feature point selection criteria. This allows for precise location of key feature positions during the entire rising phase of the fault current, obtaining several third and several fourth fault feature points. This provides a basis for subsequently constructing several second fault slope lines and calculating the apparent time of the entire wavefront. Finally, several second fault slope lines are constructed using several third fault feature points and several fourth fault feature points. Based on these second fault slope lines and several fault transient waveforms, several full-segment apparent times of the wavefront are obtained. This allows for the quantification of the rate characteristics of the rise of the fault current across the entire segment, thus obtaining another core time-domain indicator characterizing fault safety performance.

[0015] Furthermore, the acquisition of several overshoot values ​​and several rise times based on several step response waveforms includes: Several first current peak values ​​and several target steady-state current values ​​are obtained based on several step response waveforms; Several overshoot values ​​are obtained based on several first current peak values ​​and several target steady-state current values; Based on the third preset feature point selection condition, feature points are extracted from several step response waveforms to obtain several first step feature points and several second step feature points. Several rise times are obtained based on several first step feature points and several second step feature points.

[0016] In the above scheme, by obtaining several first current peak values ​​and several target steady-state current values ​​from several step response waveforms, key numerical characteristics of the current during the dynamic response process can be accurately extracted, providing basic data for calculating overshoot. Next, by obtaining several first current peak values ​​and several target steady-state current values, several overshoot values ​​can be obtained, quantifying the degree to which the current deviates from the steady-state value during a power step, thus obtaining a core indicator characterizing the stability of dynamic regulation. Then, by extracting feature points from several step response waveforms using a third preset feature point selection condition, key time nodes when the current rises to a specific proportion of the steady-state value can be accurately located, obtaining several first step feature points and several second step feature points, providing a basis for calculating the rise time. Finally, by obtaining several rise times from several first step feature points and several second step feature points, the response speed at which the current reaches the steady-state value after a power step can be quantified, thus obtaining a core indicator characterizing the speed of dynamic regulation.

[0017] Further, the step of constructing several utopian lines based on several performance mapping models, obtaining several candidate solution points based on several utopian lines, and calculating several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points includes: Several first anchor points and several second anchor points are obtained based on several performance mapping models, and several utopian lines are constructed based on several first anchor points and several second anchor points. Several seed points are obtained based on several utopian lines, and several candidate solution points are obtained by searching the seed points based on a preset unit normal vector. Based on the candidate solution points, calculate a number of positive ideal solutions and a number of negative ideal solutions, and based on the candidate solution points, the positive ideal solutions and the negative ideal solutions, calculate a number of positive ideal solution distances and a number of negative ideal solution distances.

[0018] In the above scheme, several first anchor points and several second anchor points are obtained through several performance mapping models. Based on these first and second anchor points, several utopian lines are constructed, which can delineate the extreme boundary of the dual objectives of fault safety performance and dynamic adjustment performance, thus defining a clear performance range for subsequent point selection and optimization. Next, several seed points are obtained through the utopian lines, and the seed points are searched separately based on a preset unit normal vector. This allows for the selection of effective inductance parameter solutions that balance fault safety performance and dynamic adjustment performance along the direction of simultaneous optimization of the dual objectives, while eliminating invalid solutions with performance imbalances, thus obtaining several candidate solution points and locking in the effective candidate range of inductance values. Then, several positive ideal solutions and several negative ideal solutions are calculated through the candidate solution points, and the distances between the positive and negative ideal solutions are calculated based on these candidate solution points, positive ideal solutions, and negative ideal solutions. This establishes the optimal and worst quantitative benchmarks for the dual objective performance, transforming the balanced performance of each candidate solution point into a quantifiable distance index, providing an objective numerical basis for subsequent comprehensive performance selection.

[0019] This invention provides a system for obtaining the inductance value of a current-limiting reactor, including an initial mapping model construction module, a performance mapping model fitting module, a performance screening module, and a setting inductance value acquisition module, specifically: The initial mapping model construction module is used to obtain the candidate inductor sequence of the current-limiting reactor to be selected, and to perform fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors, so as to construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score. The performance mapping model fitting module is used to fit several initial mapping models respectively, obtain several first coefficients, several second coefficients and several third coefficients, and obtain several performance mapping models based on several first coefficients, several second coefficients, several third coefficients and several initial mapping models. The performance screening module is used to construct several utopian lines based on several performance mapping models, and obtain several candidate solution points based on several utopian lines, so as to calculate several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points. The module for obtaining the set inductance value is used to calculate the relative proximity of several candidate solution points based on several positive ideal solution distances and several negative ideal solution distances, and to determine several comprehensive performance points based on preset selection conditions and several relative proximity. Then, it uses reverse indexing based on several comprehensive performance points and several performance mapping models to obtain candidate set inductance values.

[0020] This invention provides a system for obtaining the inductance value of a current-limiting reactor. In practical applications, only an initial mapping model construction module is needed. Fault simulation and dynamic response simulation are performed on each candidate inductor to obtain the corresponding comprehensive safety index score and dynamic performance comprehensive index score. Then, an initial mapping model is constructed using these scores, which correlates the candidate inductance value with fault safety performance and dynamic adjustment performance, providing an initial mapping model for subsequent operations. Next, a performance mapping model fitting module is used to fit several initial mapping models, obtaining several performance mapping models. This establishes an accurate nonlinear mapping relationship between candidate inductance, fault safety performance, and dynamic adjustment performance, providing model support for subsequent optimization and balancing of candidate inductance values ​​to obtain the candidate setting inductance value. Then, a performance screening module is used to construct a utopian line through several performance mapping models. Based on this line, several candidate solution points are obtained, and the corresponding positive and negative ideal solution distances are calculated. This allows for the delineation of the dual-objective extreme boundary of fault safety performance and dynamic adjustment performance, screening out the inductor parameter range that simultaneously considers both. This provides a clear and effective reference range for selecting candidate setting inductance values ​​for the next phase of the current-limiting reactor. Subsequently, a setting inductance value acquisition module is used to calculate the relative proximity of several candidate solution points using several positive and negative ideal solution distances. Based on preset selection conditions and relative proximity, a comprehensive performance point is determined. This allows for the selection of the balance between fault safety performance and dynamic adjustment performance among several candidate solution points, resulting in a comprehensive performance point that satisfies both fault safety performance and dynamic adjustment performance. Finally, by using several comprehensive performance points and several performance mapping models to perform reverse indexing, candidate setting inductance values ​​are obtained. This allows for the output of candidate setting inductance values ​​for current-limiting reactors that balance fault safety performance and dynamic regulation performance. This avoids the decline in power system stability caused by selecting too high an inductance value for the line current-limiting reactor, and ultimately achieves a balance between fault safety and dynamic regulation in reactor parameters.

[0021] Further, the initial mapping model construction module is used to obtain a candidate inductor sequence for the current-limiting reactor to be selected, and to perform fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain a comprehensive safety index score and a comprehensive dynamic performance index score of several candidate inductors, so as to construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score, including: Based on the preset inductance value range of the current-limiting reactor to be selected, a sequence of candidate inductors is obtained. For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed respectively to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on the several effective fault transient waveforms and several effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained. Several initial mapping models are constructed based on the scores of several comprehensive security indicators and several comprehensive dynamic performance indicators.

[0022] In the above scheme, a candidate inductor sequence is obtained by using the preset inductance value range of the current-limiting reactor to be selected. This determines the screening range of inductor parameters, providing standardized inductor samples for subsequent selection, avoiding blind simulation without a range, and improving selection efficiency. Next, by conducting fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence, the corresponding effective fault transient waveform and effective step response waveform are obtained. This allows the candidate inductors to be correlated with fault safety performance and dynamic adjustment performance. Furthermore, comprehensive safety index scores and comprehensive dynamic performance index scores, which can be used for modeling, are calculated from the effective fault transient waveform and effective step response waveform, providing a basis for constructing the initial mapping model. Then, several initial mapping models are constructed using several comprehensive safety index scores and several comprehensive dynamic performance index scores, providing an initial model foundation for subsequent model fitting.

[0023] Further, the step involves performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on these effective fault transient waveforms and effective step response waveforms, the step also involves obtaining a comprehensive safety index score and a comprehensive dynamic performance index score for several candidate inductors, including: For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed to obtain several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors. Based on the preset fault time window, the preset step response time window, several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. Based on several valid fault transient waveforms and several valid step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained.

[0024] In the above scheme, by conducting fault simulation and dynamic response simulation for each candidate inductor in the candidate inductor sequence, several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors are obtained. This allows for the collection of full-time current response data for each candidate inductor under different fault conditions and dynamic disturbance conditions, providing raw waveform data for subsequent extraction of effective performance data. Next, by presetting fault time windows, presetting step response time windows, and several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. This allows for the extraction of effective time period data from the full-time waveforms, eliminating invalid waveform information, and providing accurate effective waveforms for subsequent index score calculation. Then, through several effective fault transient waveforms and several effective step response waveforms, performance characteristic indicators can be extracted from the effective waveforms, obtaining comprehensive safety index scores and comprehensive dynamic performance index scores for several candidate inductors that can be directly used for modeling, thus realizing the correlation between candidate inductors and fault safety performance and dynamic adjustment performance. Attached Figure Description

[0025] To more clearly illustrate the technical solution of this application, 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 from these drawings without creative effort.

[0026] Figure 1 A flowchart illustrating a method for obtaining the inductance value of a current-limiting reactor according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a four-terminal bipolar DC transmission model provided in an embodiment of the present invention; Figure 3 This is a definition diagram of the equivalent time index of the initial wavefront provided in an embodiment of the present invention; Figure 4 A full-segment wavefront apparent time index definition diagram is provided as an embodiment of the present invention; Figure 5 A definition diagram of overshoot and rise time indicators provided in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the optimization principle of the normal boundary intersection method according to an embodiment of the present invention. Figure 7 A Pareto front diagram provided in one embodiment of the present invention; Figure 8 This is an architecture diagram of an inductance value acquisition system for a current-limiting reactor provided in an embodiment of the present invention; Figure 9This invention provides a line-mode current waveform diagram of a line 1 experiencing a positive ground fault, according to an embodiment of the present invention. Figure 10 This invention provides a calculation diagram of indicators for a positive ground fault occurring in line 1, according to an embodiment of the present invention. Figure 11 A line-mode current waveform diagram of a converter station 1 operating under a 30% power step, provided as an embodiment of the present invention; Figure 12 A fitting curve of the comprehensive safety index score F1 and the inductance value L provided in an embodiment of the present invention; Figure 13 A fitting curve of dynamic performance comprehensive index score F2 and inductance value L provided in an embodiment of the present invention; Figure 14 This is a diagram illustrating the TOPSIS solution process according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, 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.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0029] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0030] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0032] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0033] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0034] See Figure 1 To avoid a decrease in power system stability due to excessively high inductance values ​​in line current-limiting reactors, and to achieve a balance between fault safety and dynamic adjustability in reactor parameters, this embodiment provides a method for obtaining the inductance value of current-limiting reactors. The flowchart of this method can be found in [link to flowchart]. Figure 1 ,include: Step S1: Obtain the candidate inductor sequence of the current-limiting reactor to be selected, and perform fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors, and construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score. Step S2: Fit several initial mapping models respectively to obtain several first coefficients, several second coefficients and several third coefficients, and obtain several performance mapping models based on several first coefficients, several second coefficients, several third coefficients and several initial mapping models; Step S3: Construct several utopian lines based on several performance mapping models, and obtain several candidate solution points based on several utopian lines, so as to calculate several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points; Step S4: Calculate the relative proximity of several candidate solution points based on several positive ideal solution distances and several negative ideal solution distances, and determine several comprehensive performance points based on preset selection conditions and several relative proximity. Then, perform reverse indexing based on several comprehensive performance points and several performance mapping models to obtain candidate tuning inductance values.

[0035] In this embodiment, a four-terminal bipolar DC transmission model was built based on the PSCAD / EMTDC simulation platform, such as... Figure 2 As shown, red represents the positive electrode and black represents the negative electrode. The specific modeling and parameter configuration are as follows: (1) The model adopts a four-terminal ring network architecture, consisting of four converter stations (MMC1-MMC4), several smoothing reactors and several DC circuit breakers. Each converter station is connected in a closed loop through a bipolar DC line. (2) The rated DC voltage of the model is set to ±500kV, the rated capacity of MMC1 station is 3000MW, and the rated capacity of the other converter stations is 1500MW. The converter adopts modular multilevel converter (MMC) technology, the sub-module (SM) adopts half-bridge circuit structure, and the converter transformer ratio is set to 230kV / 515kV. (3) The model adopts a master-slave control scheme in steady state. MMC1 usually maintains the DC voltage stability, while the other converter stations control the active power. To evaluate the dynamic performance, the four converter stations are made to take turns as disturbance sources to generate power steps (such as from 0 to 100MW), and when a disturbance occurs at one station, the control strategies of the other three converter stations remain unchanged. (4) The transmission line adopts the frequency-dependent distributed parameter model. In this model, except for the parameter L of the current-limiting reactor to be selected as the only independent variable of the discrete step length scan, the other main electrical parameters are strictly set according to the standard parameters of the demonstration project.

[0036] In this embodiment, the smoothing reactor at the outlet of converter station 1 in the four-terminal bipolar DC transmission model is used as the candidate current-limiting reactor. The candidate value range of parameter L of the candidate current-limiting reactor is set to [10mH, 1000mH]. A set of discrete candidate inductance sequences arranged in ascending order is generated with a step size of 10mH. Fault simulation and dynamic response simulation are performed on each candidate inductor in the candidate inductor sequence. By conducting fault simulation and dynamic response simulation on each candidate inductor, the corresponding comprehensive safety index score and dynamic performance comprehensive index score are obtained. Then, an initial mapping model is constructed based on the comprehensive safety index score and dynamic performance comprehensive index score, which can associate the candidate inductor value with fault safety performance and dynamic adjustment performance, providing an initial mapping model for subsequent processing.

[0037] Next, several performance mapping models are obtained by fitting several initial mapping models respectively. Specifically, convex function constraints are introduced during the fitting process. In the formula, Here, represents the coefficients of the quadratic form, and k is the index of the objective function, k=1,2. Subsequently, the least squares method is used to fit the coefficient vector of the function. The solution is obtained by minimizing the sum of squared residuals. In the formula, N represents the number of all candidate inductors; k is the index of the objective function, k=1,2. Through the above solution, two continuously differentiable and convex analytic mapping equations can be obtained, thus forming... This allows for the establishment of an accurate nonlinear mapping relationship between candidate inductance, fault safety performance, and dynamic adjustment performance, providing model support for subsequent optimization and balancing of candidate inductance values ​​to obtain candidate setting inductance values. Then, a utopian line is constructed using several performance mapping models. Based on this line, several candidate solution points are obtained, and the corresponding positive and negative ideal solution distances are calculated. This allows for the delineation of the dual-objective extreme boundary for both fault safety performance and dynamic adjustment performance, screening out the range of inductance parameters that simultaneously considers both. This provides a clear and effective reference interval for subsequently selecting candidate setting inductance values ​​for the current-limiting reactor.

[0038] Subsequently, the relative proximity of several candidate solution points is calculated using several positive ideal solution distances and several negative ideal solution distances. Then, the comprehensive performance point is determined based on preset selection conditions and the relative proximity. Specifically, based on several positive ideal solution distances and several negative ideal solution distances, the relative proximity of the candidate solution points is calculated according to the following formula: ; In the formula, This represents the distance from the candidate solution point to the corresponding positive ideal solution. This represents the distance from the candidate solution point to the corresponding positive or negative ideal solution. To determine the relative proximity, a comprehensive performance point is determined based on preset selection conditions and the relative proximity. This allows for the selection of a balance between fault safety performance and dynamic regulation performance among several candidate solutions, resulting in a comprehensive performance point that satisfies both fault safety and dynamic regulation performance. The preset selection condition is to take the maximum relative proximity. Finally, candidate setting inductance values ​​are obtained through reverse indexing using several comprehensive performance points and several performance mapping models. This outputs candidate setting inductance values ​​for the current-limiting reactor that balance fault safety and dynamic regulation performance, thereby avoiding a decrease in power system stability caused by selecting an excessively high inductance value for the line current-limiting reactor. Ultimately, this achieves a balance between fault safety and dynamic regulation in the reactor parameters.

[0039] Further, the process involves obtaining a candidate inductor sequence for the current-limiting reactor to be selected, and performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain a comprehensive safety index score and a comprehensive dynamic performance index score for several candidate inductors. Several initial mapping models are then constructed based on these comprehensive safety index scores and comprehensive dynamic performance index scores, including: Based on the preset inductance value range of the current-limiting reactor to be selected, a sequence of candidate inductors is obtained. For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed respectively to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on the several effective fault transient waveforms and several effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained. Several initial mapping models are constructed based on the scores of several comprehensive security indicators and several comprehensive dynamic performance indicators.

[0040] In this embodiment, a candidate inductor sequence is obtained by using the preset inductance value range of the current-limiting reactor to be selected. This determines the screening range of inductor parameters, providing standardized inductor samples for subsequent selection, avoiding blind simulation without a range, and improving selection efficiency. Next, by performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence for each line, the corresponding effective fault transient waveform and effective step response waveform are obtained. This allows the candidate inductors to be correlated with fault safety performance and dynamic adjustment performance. Furthermore, the comprehensive safety index score and dynamic performance comprehensive index score, which can be used for modeling, are calculated using the effective fault transient waveform and effective step response waveform, thus providing a basis for constructing the initial mapping model. The fault simulation includes positive grounding fault, negative grounding fault, and inter-pole short circuit fault. For each candidate inductor L, three types of fault simulations are performed on four lines, therefore each candidate inductor corresponds to 12 sets of faults.

[0041] Then, several initial mapping models are constructed using several comprehensive security index scores and several comprehensive dynamic performance index scores, as follows: In the formula, These are the fitting coefficients to be solved; For security mapping functions; This is a dynamic performance mapping function. The resulting initial mapping model can provide an initial model foundation for subsequent model fitting.

[0042] Further, the step involves performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on these effective fault transient waveforms and effective step response waveforms, the step also involves obtaining a comprehensive safety index score and a comprehensive dynamic performance index score for several candidate inductors, including: For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed to obtain several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors. Based on the preset fault time window, the preset step response time window, several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. Based on several valid fault transient waveforms and several valid step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained.

[0043] In this embodiment, by performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence, several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors are obtained. This allows for the collection of full-time current response data for each candidate inductor under different fault conditions and dynamic disturbances, providing raw waveform data for subsequent extraction of effective performance data. Next, by using a preset fault time window, a preset step response time window, several complete fault transient waveforms, and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. This allows for the extraction of effective time period data from the full-time waveforms, eliminating invalid waveform information, and providing accurate effective waveforms for subsequent index score calculation. The preset fault time window is 50ms after the fault occurs, and the fault sampling rate is... The preset fault time window contains a total of 0.05× =2500 fault sampling points; the preset step response time window is 0.5s after the step response, and the step sampling rate is The time window contains a total of 0.5× =500 step sampling points.

[0044] The specific process for obtaining the effective fault transient waveform diagram is as follows: Within a preset fault time window after the fault occurs, the positive and negative current data of the DC line where the candidate inductor is located are collected. Let the collected original positive and negative current data matrices be respectively... and : pass Synthesize the positive and negative current matrices into a line-mode current matrix. For positive grounding faults, negative grounding faults, and inter-electrode short-circuit faults, the corresponding line-mode current characteristic matrices are calculated and the datasets are denoted as the following set: In the formula, , and These are the positive grounding fault matrix, negative grounding fault matrix, and inter-electrode short-circuit fault matrix, respectively, with a dimension of 4×N (4 fault locations corresponding to 4 lines, N sampling points). Each row vector of the matrix represents the line-mode current sequence collected when a specific fault occurs on a specific line, and each column represents the discrete sampling time within a time window. Concatenating these three 4×N matrices yields the candidate inductor. The corresponding 12×N full-condition fault feature matrix : Through this Several valid fault transient waveform diagrams can be obtained.

[0045] The specific process for obtaining the effective step response waveform is as follows: In this embodiment, converter station k (k=1,2,3,4) is used as the disturbance source in turn, while the control strategies of the other converter stations remain unchanged. The power command of the converter station is controlled to step from 0 to 100MW at a ratio of 30%, 60%, and 100%. The positive and negative pole current data of the DC line during the power step process are collected. Let the collected original data matrices of positive and negative pole currents be respectively... and : pass Synthesize the positive and negative current matrices into a line-mode current matrix. For the percentages of 30%, 60%, and 100% jumping from 0 to 100MW, the corresponding line-mode current characteristic matrices were calculated and the datasets were denoted as the following set: In the formula, , , These are the 30% power step response matrix, 60% power step response matrix, and 100% power step response matrix, respectively. Each row vector of the matrix represents the line-mode current response sequence collected when a specific converter station is designated as the disturbance source and the other converter stations remain unchanged. Each column represents the specific sampling time within the dynamic response time window (0.5s).

[0046] The above three By concatenating the matrices, the candidate inductor can be obtained. corresponding Dynamic performance characteristic matrix under all operating conditions : Through this Several effective step response waveforms can be obtained.

[0047] Then, by using several effective fault transient waveforms and several effective step response waveforms, performance characteristic indicators can be extracted from the effective waveforms to obtain comprehensive safety index scores and dynamic performance comprehensive index scores for several candidate inductors that can be directly used for modeling, thus realizing the correlation between candidate inductors and fault safety performance and dynamic adjustment performance.

[0048] Furthermore, the step of obtaining the comprehensive safety index score and the comprehensive dynamic performance index score corresponding to several candidate inductors based on several effective fault transient waveform diagrams and several effective step response waveform diagrams includes: Based on several fault transient waveform diagrams, obtain several initial wavefront equivalent times and several full-segment wavefront apparent times; Based on several initial wavefront equivalent times and several full-segment wavefront apparent times, obtain the initial wavefront index scores and full-segment wavefront index scores for several candidate inductors. Based on several initial wavefront index scores and several full-segment wavefront index scores, obtain the comprehensive safety index scores corresponding to several candidate inductors. Several overshoot values ​​and several rise times are obtained based on several step response waveforms; Based on several overshoot and several rise times, obtain the overshoot index score and the rise time index score of several candidate inductors. The dynamic performance comprehensive index score of several candidate inductors is obtained based on the scores of several overshoot indexes and several rise time indexes.

[0049] In this embodiment, by using several fault transient waveform diagrams, core characteristic quantities representing the rise rate of fault current can be extracted, and several initial wavefront equivalent times and several full-segment wavefront apparent times can be obtained, providing a basic time-domain index for quantitatively evaluating fault safety performance. Next, by using several initial wavefront equivalent times and several full-segment wavefront apparent times, initial wavefront index scores and full-segment wavefront index scores corresponding to several candidate inductors are obtained. Specifically, for each candidate inductor, the minimum value of the initial wavefront equivalent time and full-segment wavefront apparent time under 12 faults is selected as the candidate inductor. Corresponding initial wave head index score The full-segment wavefront index score corresponding to the candidate inductor This allows the basic time-domain indicators to be transformed into a standardized scoring format, enabling a unified quantitative comparison of the fault safety performance indicators of different candidate inductors. Then, by using several initial wavefront index scores and several full-segment wavefront index scores, a comprehensive safety index score reflecting the overall fault safety performance of the candidate inductors can be obtained, specifically: , where a takes the value {1,2,...,100}; The normalized score of the initial wavefront index corresponding to the a-th candidate inductor; and These are the maximum and minimum values ​​in the initial wavefront index score sequence of all candidate inductors, respectively. In the formula, The normalized score of the full-segment wavefront index corresponding to the a-th candidate inductor is... and Let be the maximum and minimum values ​​of the full-segment wavefront index scores for all candidate inductors, respectively. These two scores are then combined using a weighted sum to synthesize a comprehensive safety index score. : In the formula, All are preset weighting coefficients. In this embodiment, 0.4 is acceptable. A value of 0.6 can be taken. The obtained comprehensive safety index score provides a basis for subsequent modeling. Subsequently, several overshoot and rise times that characterize dynamic performance can be extracted from several step response waveforms, providing a basic time-domain index for quantitatively evaluating dynamic adjustment performance. Next, overshoot index scores and rise time index scores for several candidate inductors are obtained through several overshoot and rise times. Specifically, for each candidate inductor, the minimum value of the overshoot and rise time under 12 dynamic response simulations is selected as the candidate inductor. Corresponding overshoot Rise time corresponding to the candidate inductor This allows for the transformation of basic dynamic time-domain metrics into standardized scoring formats, enabling a unified quantitative comparison of the dynamic adjustment performance metrics of different candidate inductors. Finally, a comprehensive dynamic performance score is obtained for several candidate inductors using scores for several overshoot metrics and several rise time metrics, specifically: ,in, The normalized score for the overshoot corresponding to the a-th candidate inductor is... , These are the maximum and minimum values ​​in the score sequence of all candidate inductor overshoot indicators, respectively. In the formula, The normalized score for the rise time of the a-th candidate inductor is... , Let be the maximum and minimum values ​​of the rise time index scores among all candidate inductors, respectively. These two scores are then combined using a weighted sum to form a comprehensive dynamic performance index score. : In the formula, All are preset weighting coefficients. In this embodiment, 0.5 is acceptable. A value of 0.5 can be taken. Finally, a comprehensive dynamic performance index score reflecting the overall dynamic adjustment performance of the candidate inductor can be obtained, providing a basis for subsequent modeling.

[0050] Furthermore, the acquisition of several initial wavefront equivalent times and several full-segment wavefront apparent times based on several fault transient waveform diagrams includes: Based on the first preset feature point selection condition, feature points are extracted from the transient waveforms of several faults corresponding to several candidate inductors to obtain several first fault feature points and several second fault feature points. Several first fault slope lines are constructed based on several first fault feature points and several second fault feature points, and several initial wavefront equivalent times are obtained based on several first fault slope lines and several fault transient waveform diagrams. Based on the second preset feature point selection conditions, feature points are extracted from several fault transient waveforms corresponding to several candidate inductors to obtain several third fault feature points and several fourth fault feature points. Several second fault slope lines are constructed based on several third fault feature points and several fourth fault feature points, and several full-segment wavefront apparent times are obtained based on several second fault slope lines and several fault transient waveform diagrams.

[0051] In this embodiment, feature points are extracted from several fault transient waveforms corresponding to several candidate inductors using a first preset feature point selection condition. This allows for precise location of key feature positions during the fault current rise phase, obtaining several first fault feature points and several second fault feature points. This provides a basis for subsequently constructing the first fault slope line and calculating the equivalent time of the initial wavefront. The first preset feature point selection condition is to select the moment when the fault current reaches 10% of its peak value. The time corresponding to 80% Next, several first fault slope lines are constructed using several first fault feature points and several second fault feature points. Based on these first fault slope lines and several fault transient waveform diagrams, several initial wavefront equivalent times are obtained, specifically as follows: Figure 3 As shown: Connect the first fault characteristic point ( , ) and the second fault characteristic point ( , Construct a straight line with the first fault slope, the slope of which is... The intersection of this straight line with the time axis t is denoted as O, and the intersection of this straight line with the horizontal line of the current peak is also denoted as O. The intersection point is denoted as P, and the time interval between the two intersection points is denoted as the initial wavefront equivalent time. : The obtained initial wavefront equivalent time can quantify the rate characteristic of the initial rise of the fault current, yielding a time-domain index characterizing fault safety performance. Then, by extracting feature points from several fault transient waveforms corresponding to several candidate inductors using a second preset feature point selection condition, key feature positions during the entire rise phase of the fault current can be accurately located, and several third and fourth fault feature points can be obtained. This provides a basis for subsequently constructing several second fault slope lines and calculating the apparent time of the entire wavefront. The second preset feature point selection condition is to select the moment corresponding to 30% of the peak value of the fault current. The time corresponding to 90% Finally, several second fault slope lines are constructed using several third and fourth fault feature points. Based on these second fault slope lines and several fault transient waveform diagrams, several full-segment apparent wavefront times are obtained, specifically as follows: Figure 4 As shown: Connect the first fault characteristic point ( , ) and the second fault characteristic point ( , Construct a straight line with the second fault slope, the slope of which is... The intersection of this straight line with the time axis t is denoted as K, and the intersection of this straight line with the horizontal line of the current peak is denoted as K. The intersection point is denoted as L, and the time interval between the two intersection points is denoted as the apparent time of the entire wavefront. : The obtained full-segment wavefront apparent time can quantify the rate characteristics of the rise of the fault current across the entire segment, thus obtaining another core time-domain indicator characterizing fault safety performance.

[0052] Furthermore, the acquisition of several overshoot values ​​and several rise times based on several step response waveforms includes: Several first current peak values ​​and several target steady-state current values ​​are obtained based on several step response waveforms; Several overshoot values ​​are obtained based on several first current peak values ​​and several target steady-state current values; Based on the third preset feature point selection condition, feature points are extracted from several step response waveforms to obtain several first step feature points and several second step feature points. Several rise times are obtained based on several first step feature points and several second step feature points.

[0053] In this embodiment, by obtaining several first current peak values ​​and several target steady-state current values ​​through several step response waveforms, key numerical characteristics of the current during the dynamic response process can be accurately extracted, providing basic data for calculating the overshoot. Next, several overshoot values ​​are obtained through several first current peak values ​​and several target steady-state current values, specifically as follows: Figure 5 As shown, ,in, This is the first peak current, which is the first peak in the step response waveform. The target steady-state current value is the target steady-state current value after the power step in the step response waveform. This is the overshoot. The obtained overshoot can quantify the degree to which the current deviates from the steady-state value during a power step, thus obtaining a core indicator characterizing the stability of dynamic regulation. Then, by extracting feature points from several step response waveforms using a third preset feature point selection condition, the key time node where the current rises to a specific proportion of the steady-state value can be accurately located, obtaining several first step feature points and several second step feature points. Specifically, the third preset feature point selection condition is to take the step response current rising to the steady-state value... The time corresponding to 10% And the current rises to a steady-state value 90% of the time corresponding to The obtained first-step feature points and second-step feature points provide a basis for calculating the rise time. Finally, several rise times are obtained using these first-step feature points and second-step feature points: ,in, It is the overshoot. Obtaining the rise time allows us to quantify the response speed at which the current reaches its steady-state value after a power step, thus providing a core indicator characterizing the speed of dynamic adjustment.

[0054] Further, the step of constructing several utopian lines based on several performance mapping models, obtaining several candidate solution points based on several utopian lines, and calculating several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points includes: Several first anchor points and several second anchor points are obtained based on several performance mapping models, and several utopian lines are constructed based on several first anchor points and several second anchor points. Several seed points are obtained based on several utopian lines, and several candidate solution points are obtained by searching the seed points based on a preset unit normal vector. Based on the candidate solution points, calculate a number of positive ideal solutions and a number of negative ideal solutions, and based on the candidate solution points, the positive ideal solutions and the negative ideal solutions, calculate a number of positive ideal solution distances and a number of negative ideal solution distances.

[0055] In this embodiment, several first anchor points and several second anchor points are obtained through several performance mapping models, specifically as follows: ,in, To minimize the inductance value of F1; To minimize the inductance value of F2, several first anchor points and several second anchor points are connected to each other to construct several utopian lines, specifically: In the formula, t represents a one-dimensional parameterized variable with a value range of [0,1], which can define the dual-objective extreme boundary of fault safety performance and dynamic adjustment performance, thus defining a clear performance range for subsequent point selection and optimization. Next, several seed points are obtained through several utopian lines, and normal boundary cross-optimization is performed on these seed points based on a preset unit normal vector. Specifically, on the utopian lines... By changing the value of parameter t, m seed points can be obtained. .like Figure 6 As shown, for each seed point Solve the constrained single-objective optimization subproblems as follows: ; in, This represents the step size for the search along the normal direction. The goal is to find the optimal inductance parameter L such that the performance index vector... At the boundary furthest from the Utopia line along the normal direction in the target space, an effective inductance parameter solution that balances fault-safe performance and dynamic adjustment performance can be selected along the direction of simultaneous optimization of both objectives, while invalid solutions with performance imbalances are eliminated, obtaining several candidate solution points. These candidate solution points are then used to determine their position in the target plane. Connecting these discrete performance points generates a uniformly distributed and continuously smooth Pareto front set, such as... Figure 7As shown, the effective candidate range for the inductance value is locked. The preset unit normal vector is perpendicular to the Utopia line. And the unit normal vector n points towards the origin (0,0). Then, several positive ideal solutions and several negative ideal solutions are calculated using several candidate solution points, and several positive ideal solution distances and several negative ideal solution distances are calculated based on the aforementioned candidate solution points, several positive ideal solutions, and several negative ideal solutions, specifically: in On the target plane, based on each candidate solution point on the generated Pareto front The weighted index is constructed according to the following formula: In the formula, and These are the weighted fault safety performance index and dynamic adjustment performance index, respectively. ; Then through Several positive ideal solutions were obtained from several candidate solution points. and several negative ideal solutions Then, based on several candidate solution points, several positive ideal solutions, and several negative ideal solutions, the distances between several positive ideal solutions and several negative ideal solutions are calculated: In the formula, This represents the distance from the candidate solution point to the corresponding positive ideal solution. This represents the distance from a candidate solution point to its corresponding positive or negative ideal solution. The above process establishes optimal and worst-case quantitative benchmarks for the dual-objective performance, transforming the balanced performance of each candidate solution point into a quantifiable distance index, thus providing an objective numerical basis for subsequent comprehensive performance selection.

[0056] This embodiment provides a system for obtaining the inductance value of a current-limiting reactor, such as... Figure 8 As shown, it includes an initial mapping model construction module, a performance mapping model fitting module, a performance screening module, and a tuning inductance value acquisition module, specifically: The initial mapping model construction module is used to obtain the candidate inductor sequence of the current-limiting reactor to be selected, and to perform fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors, so as to construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score. The performance mapping model fitting module is used to fit several initial mapping models respectively, obtain several first coefficients, several second coefficients and several third coefficients, and obtain several performance mapping models based on several first coefficients, several second coefficients, several third coefficients and several initial mapping models. The performance screening module is used to construct several utopian lines based on several performance mapping models, and obtain several candidate solution points based on several utopian lines, so as to calculate several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points. The module for obtaining the set inductance value is used to calculate the relative proximity of several candidate solution points based on several positive ideal solution distances and several negative ideal solution distances, and to determine several comprehensive performance points based on preset selection conditions and several relative proximity. Then, it uses reverse indexing based on several comprehensive performance points and several performance mapping models to obtain candidate set inductance values.

[0057] This embodiment provides a system for obtaining the inductance value of a current-limiting reactor. In practical applications, only an initial mapping model construction module is needed. Fault simulation and dynamic response simulation are performed for each candidate inductor to obtain the corresponding comprehensive safety index score and dynamic performance comprehensive index score. Then, an initial mapping model is constructed using these scores, which correlates the candidate inductance value with fault safety performance and dynamic adjustment performance, providing an initial mapping model for subsequent operations. Next, a performance mapping model fitting module is used to fit several initial mapping models, obtaining several performance mapping models. This establishes an accurate nonlinear mapping relationship between candidate inductance, fault safety performance, and dynamic adjustment performance, providing model support for subsequent optimization and balancing of candidate inductance values ​​to obtain the candidate setting inductance value. Then, a performance screening module is used to construct a utopian line through several performance mapping models. Based on this line, several candidate solution points are obtained, and the corresponding positive and negative ideal solution distances are calculated. This allows for the delineation of the dual-objective extreme boundary of fault safety performance and dynamic adjustment performance, screening out the inductor parameter range that simultaneously considers both. This provides a clear and effective reference range for selecting candidate setting inductance values ​​for the next phase of the current-limiting reactor. Subsequently, a setting inductance value acquisition module is used to calculate the relative proximity of several candidate solution points using several positive and negative ideal solution distances. Based on preset selection conditions and relative proximity, a comprehensive performance point is determined. This allows for the selection of the balance between fault safety performance and dynamic adjustment performance among several candidate solution points, resulting in a comprehensive performance point that satisfies both fault safety performance and dynamic adjustment performance. Finally, by using several comprehensive performance points and several performance mapping models to perform reverse indexing, candidate setting inductance values ​​are obtained. This allows for the output of candidate setting inductance values ​​for current-limiting reactors that balance fault safety performance and dynamic regulation performance. This avoids the decline in power system stability caused by selecting too high an inductance value for the line current-limiting reactor, and ultimately achieves a balance between fault safety and dynamic regulation in reactor parameters.

[0058] Further, the initial mapping model construction module is used to obtain a candidate inductor sequence for the current-limiting reactor to be selected, and to perform fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain a comprehensive safety index score and a comprehensive dynamic performance index score of several candidate inductors, so as to construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score, including: Based on the preset inductance value range of the current-limiting reactor to be selected, a sequence of candidate inductors is obtained. For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed respectively to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on the several effective fault transient waveforms and several effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained. Several initial mapping models are constructed based on the scores of several comprehensive security indicators and several comprehensive dynamic performance indicators.

[0059] In this embodiment, a candidate inductor sequence is obtained by using the preset inductance value range of the current-limiting reactor to be selected. This determines the screening range of inductor parameters, providing standardized inductor samples for subsequent selection, avoiding blind simulation without a range, and improving selection efficiency. Next, fault simulation and dynamic response simulation are performed on each candidate inductor in the candidate inductor sequence to obtain the corresponding effective fault transient waveform and effective step response waveform. This allows the candidate inductors to be correlated with fault safety performance and dynamic adjustment performance. Furthermore, comprehensive safety index scores and comprehensive dynamic performance index scores, which can be used for modeling, are calculated from the effective fault transient waveform and effective step response waveform, providing a basis for constructing the initial mapping model. Then, several initial mapping models are constructed using several comprehensive safety index scores and several comprehensive dynamic performance index scores, providing an initial model foundation for subsequent model fitting.

[0060] Further, the step involves performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on these effective fault transient waveforms and effective step response waveforms, the step also involves obtaining a comprehensive safety index score and a comprehensive dynamic performance index score for several candidate inductors, including: For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed to obtain several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors. Based on the preset fault time window, the preset step response time window, several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. Based on several valid fault transient waveforms and several valid step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained.

[0061] In this embodiment, by performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence, several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors are obtained. This allows for the collection of full-time current response data for each candidate inductor under different fault conditions and dynamic disturbance conditions, providing raw waveform data for subsequent extraction of effective performance data. Next, by using preset fault time windows, preset step response time windows, several complete fault transient waveforms, and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. This allows for the extraction of effective time period data from the full-time waveforms, eliminating invalid waveform information, and providing accurate effective waveforms for subsequent index score calculation. Then, using several effective fault transient waveforms and several effective step response waveforms, performance characteristic indicators can be extracted from the effective waveforms, obtaining comprehensive safety index scores and comprehensive dynamic performance index scores corresponding to several candidate inductors that can be directly used for modeling, thus realizing the correlation between candidate inductors and fault safety performance and dynamic adjustment performance.

[0062] To more intuitively and fully illustrate how the method for obtaining the inductance value of a current-limiting reactor provided in this embodiment can avoid a decrease in power system stability caused by selecting an excessively high inductance value for the line current-limiting reactor, and achieve a balance between fault safety and dynamic adjustability in selecting reactor parameters, the following embodiments are provided for detailed explanation: In this embodiment, the positive grounding fault feature matrix corresponding to the candidate inductance parameter L=500mH is used. Taking the first row of data (i.e., the sampling sequence when a positive ground fault occurs on line 1) as an example, the fault safety index is calculated, and its line-mode current waveform is shown in the figure below. Figure 9 As shown. Next, using MATLAB software, the time-domain waveform file generated by the PSCAD simulation is read through the data interface, as shown. Figure 10 As shown, the peak value of the line-mode current is obtained. Subsequently, the line-mode current values ​​were retrieved from the discrete sequence and reached [values]. and The corresponding sampling time and ; and The corresponding sampling time and Therefore, the slope can be calculated. , Initial wavefront equivalent time The entire wavefront appears to be in time. .

[0063] Repeat the above steps to calculate the remaining 11 operating conditions for the candidate inductor parameters. and Then, the normalized score of the initial wavefront index under the candidate inductor is obtained. Normalized score of the whole wave head index Comprehensive safety index score .

[0064] Then, the dynamic response feature matrix corresponding to the candidate inductance parameter L=500mH is used. Taking the first row vector (i.e., the operating condition where converter station 1 generates a 30% power step) as an example, dynamic performance indicators are calculated, and the line-mode current waveform is measured. Figure 11 As shown. Subsequently, using MATLAB software, the time-domain waveform file generated by the PSCAD simulation was read through the data interface to obtain the peak value of the line-mode current. Steady-state value of line mode current Subsequently, the line-mode current was retrieved from the discrete sequence and allowed to rise to its steady-state value. The time corresponding to 10% As the line mode current rises to a steady-state value 90% of the time corresponding to Next, the maximum overshoot was calculated. Ascent time .

[0065] Repeat the above steps to calculate M1 and M2 for the remaining 11 operating conditions under the candidate inductor parameters, and then obtain the normalized overshoot score for the candidate inductor. Normalized score of rise time Dynamic performance comprehensive index score .

[0066] After obtaining the comprehensive safety index score F1 and the comprehensive dynamic performance index score F2 for each candidate inductor, the results are summarized to construct a parameter evaluation score table, as shown in Table 1 below: Table 1 Summary Score Table In this embodiment, the comprehensive safety index score and the comprehensive dynamic performance index score corresponding to the different inductance values ​​are respectively fitted to obtain two fitting curves as shown below. Figure 12 and Figure 13 As shown.

[0067] Next, after fitting the performance mapping model of two continuously differentiable convex functions with inductance value L as the independent variable, the Pareto front is generated in the inductance parameter interval [Lmin, Lmax] using the Normal Boundary Intersection (NBI) method, as shown below. Figure 7 As shown in the figure, any point on this curve represents the optimal game solution for the comprehensive security index score and the comprehensive dynamic performance index score under specific weights.

[0068] Then, based on the improved TOPSIS, each candidate solution point is weighted, and its distance to the positive and negative ideal solutions is calculated, followed by the calculation of their relative proximity. As shown in the figure, the calculation verifies that when the relative proximity... When the maximum value is reached (approximately 0.5865), the coordinates of the optimal compromise performance point on the target plane are (0.4035, 0.4257). Finally, this optimal performance point is substituted back into the performance mapping model for inverse mapping, and the optimal setting parameter L = 485.62mH of the smoothing reactor is finally obtained.

[0069] This embodiment also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the functions of the system as described above.

[0070] It is understood that the above system embodiments correspond to the method embodiments of the present invention, and can realize the method for obtaining the inductance value of a current-limiting reactor provided by any of the above method embodiments of the present invention.

[0071] It should be noted that the system embodiments described above are merely illustrative, and some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0072] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for obtaining the inductance value of a current-limiting reactor, characterized in that, include: Obtain the candidate inductor sequence for the current-limiting reactor to be selected, and perform fault simulation and dynamic response simulation for each candidate inductor in the candidate inductor sequence to obtain the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors, and construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score. Several initial mapping models are fitted to obtain several first coefficients, several second coefficients and several third coefficients, and several performance mapping models are obtained based on several first coefficients, several second coefficients, several third coefficients and several initial mapping models; Several utopian lines are constructed based on several performance mapping models, and several candidate solution points are obtained based on several utopian lines, so as to calculate several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points. The relative proximity of several candidate solution points is calculated based on several positive ideal solution distances and several negative ideal solution distances. Several comprehensive performance points are determined based on preset selection conditions and several relative proximity. Then, a reverse index is performed based on several comprehensive performance points and several performance mapping models to obtain candidate tuning inductance values.

2. The method for obtaining the inductance value of a current-limiting reactor according to claim 1, characterized in that, The process involves obtaining a candidate inductor sequence for the current-limiting reactor to be selected, and performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain a comprehensive safety index score and a comprehensive dynamic performance index score for several candidate inductors. Several initial mapping models are then constructed based on these comprehensive safety index scores and comprehensive dynamic performance index scores, including: Based on the preset inductance value range of the current-limiting reactor to be selected, a sequence of candidate inductors is obtained. For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed respectively to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on the several effective fault transient waveforms and several effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained. Several initial mapping models are constructed based on the scores of several comprehensive security indicators and several comprehensive dynamic performance indicators.

3. The method for obtaining the inductance value of a current-limiting reactor according to claim 2, characterized in that, The process involves performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on these effective fault transient waveforms and effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained, including: For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed to obtain several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors. Based on the preset fault time window, the preset step response time window, several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. Based on several valid fault transient waveforms and several valid step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained.

4. The method for obtaining the inductance value of a current-limiting reactor according to claim 3, characterized in that, The process of obtaining comprehensive safety index scores and comprehensive dynamic performance index scores for several candidate inductors based on several effective fault transient waveform diagrams and several effective step response waveform diagrams includes: Based on several fault transient waveform diagrams, obtain several initial wavefront equivalent times and several full-segment wavefront apparent times; Based on several initial wavefront equivalent times and several full-segment wavefront apparent times, obtain the initial wavefront index scores and full-segment wavefront index scores for several candidate inductors. Based on several initial wavefront index scores and several full-segment wavefront index scores, obtain the comprehensive safety index scores corresponding to several candidate inductors. Several overshoot values ​​and several rise times are obtained based on several step response waveforms; Based on several overshoot and several rise times, obtain the overshoot index score and the rise time index score of several candidate inductors. The dynamic performance comprehensive index score of several candidate inductors is obtained based on the scores of several overshoot indexes and several rise time indexes.

5. The method for obtaining the inductance value of a current-limiting reactor according to claim 4, characterized in that, The acquisition of several initial wavefront equivalent times and several full-segment wavefront apparent times based on several fault transient waveform diagrams includes: Based on the first preset feature point selection condition, feature points are extracted from the transient waveforms of several faults corresponding to several candidate inductors to obtain several first fault feature points and several second fault feature points. Several first fault slope lines are constructed based on several first fault feature points and several second fault feature points, and several initial wavefront equivalent times are obtained based on several first fault slope lines and several fault transient waveform diagrams. Based on the second preset feature point selection conditions, feature points are extracted from several fault transient waveforms corresponding to several candidate inductors to obtain several third fault feature points and several fourth fault feature points. Several second fault slope lines are constructed based on several third fault feature points and several fourth fault feature points, and several full-segment wavefront apparent times are obtained based on several second fault slope lines and several fault transient waveform diagrams.

6. The method for obtaining the inductance value of a current-limiting reactor according to claim 4, characterized in that, The method of obtaining several overshoot values ​​and several rise times based on several step response waveforms includes: Several first current peak values ​​and several target steady-state current values ​​are obtained based on several step response waveforms; Several overshoot values ​​are obtained based on several first current peak values ​​and several target steady-state current values; Based on the third preset feature point selection condition, feature points are extracted from several step response waveforms to obtain several first step feature points and several second step feature points. Several rise times are obtained based on several first step feature points and several second step feature points.

7. The method for obtaining the inductance value of a current-limiting reactor according to claim 1, characterized in that, The process of constructing several utopian lines based on several performance mapping models, obtaining several candidate solution points based on several utopian lines, and calculating several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points includes: Several first anchor points and several second anchor points are obtained based on several performance mapping models, and several utopian lines are constructed based on several first anchor points and several second anchor points. Several seed points are obtained based on several utopian lines, and several candidate solution points are obtained by searching the seed points based on a preset unit normal vector. Based on the candidate solution points, calculate a number of positive ideal solutions and a number of negative ideal solutions, and based on the candidate solution points, the positive ideal solutions and the negative ideal solutions, calculate a number of positive ideal solution distances and a number of negative ideal solution distances.

8. A system for obtaining the inductance value of a current-limiting reactor, characterized in that, It includes an initial mapping model construction module, a performance mapping model fitting module, a performance screening module, and a tuning inductance value acquisition module, specifically: The initial mapping model construction module is used to obtain the candidate inductor sequence of the current-limiting reactor to be selected, and to perform fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors, so as to construct several initial mapping models based on the comprehensive safety index score and the comprehensive dynamic performance index score. The performance mapping model fitting module is used to fit several initial mapping models respectively, obtain several first coefficients, several second coefficients and several third coefficients, and obtain several performance mapping models based on several first coefficients, several second coefficients, several third coefficients and several initial mapping models. The performance screening module is used to construct several utopian lines based on several performance mapping models, and obtain several candidate solution points based on several utopian lines, so as to calculate several positive ideal solution distances and several negative ideal solution distances based on several candidate solution points. The module for obtaining the set inductance value is used to calculate the relative proximity of several candidate solution points based on several positive ideal solution distances and several negative ideal solution distances, and to determine several comprehensive performance points based on preset selection conditions and several relative proximity. Then, it uses reverse indexing based on several comprehensive performance points and several performance mapping models to obtain candidate set inductance values.

9. The inductance value acquisition system for a current-limiting reactor according to claim 8, characterized in that, The initial mapping model construction module is used to obtain a candidate inductor sequence for the current-limiting reactor to be selected, and to perform fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain a comprehensive safety index score and a comprehensive dynamic performance index score of several candidate inductors. Based on these comprehensive safety index scores and comprehensive dynamic performance index scores, several initial mapping models are constructed, including: Based on the preset inductance value range of the current-limiting reactor to be selected, a sequence of candidate inductors is obtained. For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed respectively to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on the several effective fault transient waveforms and several effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained. Several initial mapping models are constructed based on the scores of several comprehensive security indicators and several comprehensive dynamic performance indicators.

10. The inductance value acquisition system for a current-limiting reactor according to claim 9, characterized in that, The process involves performing fault simulation and dynamic response simulation on each candidate inductor in the candidate inductor sequence to obtain several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors. Based on these effective fault transient waveforms and effective step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained, including: For each candidate inductor in the candidate inductor sequence, fault simulation and dynamic response simulation are performed to obtain several complete fault transient waveforms and several complete step response waveforms corresponding to several candidate inductors. Based on the preset fault time window, the preset step response time window, several complete fault transient waveforms and several complete step response waveforms, several effective fault transient waveforms and several effective step response waveforms corresponding to several candidate inductors are obtained. Based on several valid fault transient waveforms and several valid step response waveforms, the comprehensive safety index score and the comprehensive dynamic performance index score of several candidate inductors are obtained.

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