Complex fault analysis and protection setting calculation system and method for power system distribution network

Abstract

The invention relates to the technical field of distribution network fault analysis, and proposes a complex fault analysis and protection setting calculation system and method for a power system distribution network. The system comprises an adaptive quick-break current protection module, a composite sequence network diagram analysis module, a fault current correction module and a protection setting value calculation module. The system monitors the operation status of the distribution network in real time and dynamically adjusts the protection setting value to achieve rapid response to different types of faults. The equivalent model of positive sequence, negative sequence and zero sequence impedance is used to comprehensively consider the influence of each line and load, and accurately calculate the voltage and current distribution of the fault point. In combination with the characteristics of new energy units, the fault current is corrected by an iterative algorithm to improve the accuracy of fault analysis. Accurate protection setting values ​​are provided for each branch to ensure the reliability and effectiveness of protection action, improve the analysis efficiency of complex fault analysis of the power system distribution network, and improve the response speed of the power system and the accuracy of protection setting calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network fault analysis, and in particular to a system and method for complex fault analysis and protection setting calculation of a power system distribution network. Background Art

[0002] At present, the following technical solutions are mainly used for complex fault analysis and protection setting calculation of distribution networks containing new energy sources: Three-stage protection method: By setting three stages of current quick-break protection, time-limited current quick-break protection and time-limited overcurrent protection, the action is delayed step by step to achieve selective removal of the fault section. This method relies on the preset current threshold and time delay, and determines the protection setting value through static calculation. Composite sequence network diagram model: Using the equivalent model of positive sequence, negative sequence and zero sequence impedance, the voltage and current distribution of the fault point is determined through static calculation, and then the protection setting value is set. This method performs well in the case of a single fault point, but has limitations under multi-point fault or complex fault conditions.

[0003] Although the above technical solutions can meet the fault analysis and protection needs of traditional distribution networks to a certain extent, they have the following obvious disadvantages when facing modern distribution networks containing a large number of distributed renewable energy sources: Poor adaptability: The traditional three-stage protection method and the composite sequence network diagram model are difficult to accurately identify complex faults occurring at multiple points simultaneously when faced with complex changes in the distribution network structure after the access of new energy. Especially when the new energy station is connected to the end of the distribution network feeder in a "T" connection, the number of branch lines increases and the network structure is complex, and traditional methods are difficult to adapt to such changes.

[0004] Insufficient sensitivity: When a fault occurs at the end of the distribution network or a short line, the traditional protection method may fail to operate due to insufficient sensitivity due to the small fault current. For example, in a multi-point same-phase complex grounding fault, the shunt effect caused by multiple grounding points will make the zero-sequence current of the fault feeder very small, causing the zero-sequence current protection to fail to operate.

[0005] Selectivity problem: Under the condition of multi-point out-of-phase complex grounding fault, traditional protection methods are prone to over-tripping, which will expand the scope of power outage. This is because out-of-phase fault is equivalent to phase-to-phase short circuit, and the effective value of zero-sequence current of the fault feeder increases significantly, which is easy to cause zero-sequence current protection to trip incorrectly.

[0006] Slow response speed: The response speed of traditional protection methods is slow and cannot meet the needs of rapid fault removal. Especially when the excitation response time constant of new energy power stations is low, the response speed of traditional methods is not enough to remove the fault in time, which may cause the fault to expand.

[0007] Low model accuracy: Traditional fault analysis models ignore the impact of the excitation control system of new energy units on their fault characteristics, resulting in inaccurate analysis results. The fault analysis model of constant voltage source series constant impedance suitable for conventional large-capacity generators is not suitable for fault characteristic analysis of new energy units.

[0008] Therefore, how to improve the scenario adaptability and analysis efficiency of complex fault analysis in power system distribution networks, ensure the stability and reliability of distribution networks, and improve the response speed of power systems and the accuracy of protection setting calculations is a technical problem that needs to be solved urgently. Summary of the invention

[0009] The present invention provides a system and method for complex fault analysis and protection setting calculation of a power system distribution network, aiming to solve at least one of the technical problems raised above.

[0010] A first aspect of the present invention provides a power system distribution network complex fault analysis and protection setting calculation system, comprising: An adaptive quick-break current protection module is configured to obtain operation status monitoring data of the distribution network, determine a protection setting value based on the operation status monitoring data, and use the protection setting value to perform protection actions of the distribution network for different fault types; A composite sequence network diagram analysis module is configured to obtain feeder-related parameters of the distribution network, construct a composite sequence network diagram of the distribution network, perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, and generate a voltage and current distribution result of a fault point of the distribution network; A fault current correction module receives the operation status monitoring data and the voltage and current distribution result of the fault point, and is configured to correct the fault current by using a dynamic excitation response correction algorithm based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network to obtain a fault current correction result; The protection setting value calculation module receives the operation status monitoring data, the voltage and current distribution results of the fault point and the fault current correction result, and is configured to calculate the protection setting value of each branch using an adaptive multi-spectrum setting value optimization algorithm.

[0011] Optionally, the adaptive quick-break current protection module specifically includes: The data acquisition unit is configured to collect current data and voltage data of the distribution network in real time through current transformers and voltage transformers installed in each branch, and output the current data and voltage data as operation status monitoring data; a fault detection unit configured to receive the real-time data collected by the data collection unit and to quickly identify the fault type and location of the distribution network using a dynamic multi-spectrum fault detection algorithm; A set value calculation unit is configured to generate protection set values ​​for dynamic adjustment of the distribution network under different fault conditions according to the fault detection result; The protection execution unit is configured to execute protection actions of the distribution network for different fault types according to the protection setting.

[0012] Optionally, a dynamic multi-spectrum fault detection algorithm is used to quickly identify the fault type and location of the distribution network, including: Through Fourier transform, the current data of the distribution network is decomposed into fundamental wave and harmonic components to construct fault features. The constructed fault features are combined with preset fault judgment criteria to identify the fault type and location of the distribution network. The expression for constructing fault characteristics by decomposing the current data of the distribution network into fundamental wave and harmonic components is specifically: ; In the formula, Indicates that a branch is at time The current, is the DC component, It is The amplitude of the subharmonics, is the fundamental frequency, It is The phase angle of the subharmonic.

[0013] Optionally, generate expressions for protection settings of the distribution network dynamically adjusted under different fault conditions, specifically: ; ; in, Indicates at time The protection value of Indicates the basic value, and are the maximum current and minimum current at the current moment, is the adjustment factor, is the fault current, is the current during normal operation.

[0014] Optionally, the composite sequence network diagram analysis module specifically includes: The system parameter input unit is configured to obtain feeder-related parameters of the distribution network; wherein the feeder-related parameters include line parameters, load parameters, fault point location, fault phase, negative sequence impedance and access location of each feeder of the distribution network; A composite sequence network diagram construction unit is configured to construct a composite sequence network diagram of the distribution network based on the received feeder-related parameters of the distribution network and the equivalent relationship between the positive sequence, negative sequence and zero sequence impedances of each line and the load; A fault analysis unit is configured to perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, perform fault current calculation, fault point voltage calculation and fault type judgment of the distribution network, and generate a voltage and current distribution result of the fault point of the distribution network; The result output unit is configured to transmit the generated voltage and current distribution results of the fault point of the distribution network to the protection setting value calculation module and provide a fault visualization interface.

[0015] Optionally, based on the equivalent relationship between the positive sequence, negative sequence and zero sequence impedance of each line and the load, a composite sequence network diagram of the distribution network is constructed, specifically including: Based on the positive-sequence, negative-sequence and zero-sequence impedances of each line and load, a multi-spectrum composite sequence network diagram construction method is used to integrate the positive-sequence, negative-sequence and zero-sequence networks with the equivalent impedance mathematical calculation model of the positive-sequence, negative-sequence and zero-sequence impedances of the load to construct a composite sequence network diagram; Among them, the expression of the equivalent impedance mathematical calculation model is specifically: ; ; ; ; in, represents the equivalent impedance, is the positive sequence impedance, is the negative sequence impedance, is the zero-sequence impedance, is the positive sequence resistance, is the positive sequence reactance, is an imaginary unit, is the negative sequence resistance, is the negative sequence reactance, is the zero-sequence resistance, is the zero-sequence reactance.

[0016] Optionally, the fault current calculation, fault point voltage calculation and fault type determination of the distribution network are performed, specifically including: According to the composite sequence network diagram, calculate the fault current of each branch, and calculate the voltage of the fault point according to the fault current and the composite sequence network diagram; determine the fault type according to the voltage and current distribution of the fault point; Among them, the expressions of fault current and fault point voltage are as follows: ; ; In the formula, is the fault current, is the supply voltage, is the equivalent impedance, is the fault point voltage; Among them, the criteria for determining the fault type are specifically: Single-phase grounding: Fault point voltage is the zero sequence voltage, fault current is the zero-sequence current; phase-to-phase short circuit: fault point voltage is the negative sequence voltage, the fault current Negative sequence current; three-phase short circuit: fault point voltage is the positive sequence voltage, the fault current is the positive sequence current.

[0017] Optionally, based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network, a dynamic excitation response correction algorithm is used to correct the fault current to obtain a fault current correction result, specifically including: According to the fault point voltage and current distribution data provided by the composite sequence network diagram analysis module, the initial fault current of each branch is calculated. Considering the excitation response characteristics of the new energy unit, the initial fault current is corrected by excitation response. The iterative algorithm is used to gradually correct the fault current. After multiple iterative corrections, the final fault current value is output to the protection setting value calculation module; Among them, the calculation expression of the initial fault current is as follows: ; In the formula, is the fault point voltage, is the equivalent impedance; Among them, the calculation expression of excitation response correction is as follows: ; In the formula, is the corrected fault current, is the excitation response correction factor, is the fault output current of the new energy unit, the excitation response correction coefficient Calculated by the following formula: ; In the formula, is the excitation response time constant of the new energy unit, is the maximum protection action time; Among them, the expression of corrected fault current is: ; In the formula, It is The fault current after iterations is It is The fault current after iterations is is the iteration correction coefficient, the iteration correction coefficient Calculated by the following formula: ; The iteration process continues until the correction value of the fault current converges to a stable value. The convergence condition is determined by the following formula: ; In the formula, is the convergence threshold.

[0018] Optionally, an adaptive multi-spectrum setting value optimization algorithm is used to calculate the protection setting value of each branch, specifically including: Calculate the initial protection setting value of each branch according to the voltage and current distribution result of the fault point, consider the fault current correction result, make a first correction to the initial setting value, consider the operation status monitoring data, make a second correction to the initial setting value after the first correction, adopt an iterative optimization algorithm, gradually optimize the protection setting value, and output the protection setting value after multiple iterations of optimization as the final protection setting value; Among them, the expression for calculating the initial protection setting value of each branch is as follows: ; ; In the formula, is the initial protection setting value, is the basic value, and are the maximum current and minimum current at the current moment, is the initial adjustment factor, is the current during normal operation; Among them, the expression for the first correction of the initial setting value is as follows: ; ; In the formula, is the corrected protection setting value, is the fault current correction factor, is the final fault current value of the fault current correction module, is the correction factor, which is set according to the actual application requirements; Among them, the expression for the second correction of the initial setting value is as follows: ; ; In the formula, is the final protection setting value, is the operating status correction factor, It is the real-time current value provided by the adaptive fast-break current protection module. is the real-time monitoring cycle, is the maximum protection action time; Among them, the iterative optimization algorithm gradually optimizes the expression of the protection setting value, which is specifically: ; ; In the formula, It is The protection setting value after iterations is: It is The protection setting value after iterations is: is the iterative optimization coefficient; the iteration process continues until the optimized value of the protection setting value converges to a stable value. The convergence condition is determined by the following formula: ; in, It is the convergence threshold and can be set according to actual application requirements.

[0019] A second aspect of the present invention provides a method for complex fault analysis and protection setting calculation of a power system distribution network, the method comprising: S1: Acquire operation status monitoring data of the distribution network, determine a protection setting value based on the operation status monitoring data, and use the protection setting value to perform protection actions for different fault types of the distribution network; S2: Obtain feeder-related parameters of the distribution network, construct a composite sequence network diagram of the distribution network, perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, and generate voltage and current distribution results of fault points in the distribution network; S3: receiving the operation status monitoring data and the voltage and current distribution result of the fault point, and based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network, correcting the fault current by using a dynamic excitation response correction algorithm to obtain a fault current correction result; S4: receiving the operation status monitoring data, the voltage and current distribution results of the fault point and the fault current correction results, and calculating the protection setting value of each branch using an adaptive multi-spectrum setting value optimization algorithm.

[0020] The beneficial effects of the present invention are: (1) Adaptive quick-break current protection technology The protection methods in the prior art are prone to over-tripping under multi-point fault conditions, which leads to the expansion of power outages and insufficient selectivity and sensitivity of protection. By real-time monitoring of the operating status of the distribution network and dynamically adjusting the protection setting, a rapid response to different types of faults can be achieved. This technology uses high-precision sensors and high-speed communication networks to collect current and voltage data from each branch of the distribution network in real time, and dynamically adjusts the protection setting through an adaptive algorithm. The selectivity and sensitivity of the protection are significantly improved, the over-tripping phenomenon is effectively avoided, and the stability and reliability of the system are ensured. Under multi-point fault conditions, the fault section can be accurately identified to avoid unnecessary expansion of the power outage range.

[0021] (2) Composite sequence network diagram analysis technology The fault analysis model in the existing technology ignores the influence of the excitation control system of the new energy unit on its fault characteristics, resulting in inaccurate analysis results and affecting the stability of the system. Using the equivalent model of positive-sequence, negative-sequence and zero-sequence impedance, the influence of each line and load is comprehensively considered to accurately calculate the voltage and current distribution of the fault point. This technology comprehensively reflects the electrical characteristics of the distribution network under different fault conditions by constructing a composite sequence network diagram. It improves the accuracy of fault analysis and provides a reliable basis for the calculation of protection setting values. Especially in the distribution network containing new energy, it can fully consider the influence of positive-sequence, negative-sequence and zero-sequence impedance, ensure the accuracy of fault analysis, and improve the adaptability and reliability of the system.

[0022] (3) Fault current correction technology The fault current calculation method in the prior art ignores the excitation response characteristics of the new energy unit, resulting in inaccurate calculation of the fault current and affecting the reliability of the protection action. Combined with the excitation response characteristics of the new energy unit, the fault current is dynamically corrected through an iterative algorithm to improve the accuracy of fault analysis. This technology gradually corrects the fault current through a dynamic excitation response correction algorithm to ensure the accuracy of fault analysis. It solves the problem that the traditional fault analysis model ignores the characteristics of the new energy unit and ensures the accurate calculation of the fault current. Especially under the conditions of multi-point faults and short lines, it can effectively improve the accuracy of fault analysis, enhance the stability and reliability of the system, and ensure the reliability and selectivity of the protection action.

[0023] (4) Adaptive multi-spectrum setting value optimization algorithm The protection setting value calculation method in the prior art is based on static data and is difficult to adapt to the real-time changing operating status, resulting in the problem that the setting value is not accurate enough. The output results of the adaptive quick-break current protection module, the composite sequence network diagram analysis module and the fault current correction module are comprehensively considered to dynamically adjust the protection setting value. The algorithm gradually optimizes the protection setting value through an adaptive multi-spectrum setting value optimization algorithm to ensure that it converges to a stable value. The accuracy and reliability of the protection setting value are ensured, and the selectivity and rapidity of the protection action are improved. Especially in the distribution network containing new energy, the protection setting value can be dynamically adjusted to ensure the reliability and selectivity of the protection action, improve the overall performance of the system, and ensure the stability and reliability of the system.

[0024] (5) Real-time data collection and transmission technology The data collection and transmission methods in the prior art have problems of delay and data loss, which affect the accuracy of fault detection and protection setting value calculation. High-precision sensors and high-speed communication networks are used to collect and transmit the current and voltage data of the distribution network in real time. This technology uses high-precision sensors to collect the current and voltage data of each branch of the distribution network in real time, and transmits it to the central processing unit through a high-speed communication network to ensure the real-time and accuracy of the data. The real-time and accuracy of the data are ensured, providing reliable data support for fault detection and protection setting value calculation. Especially under multi-point fault conditions, it can ensure the integrity and reliability of the data, improve the response speed and reliability of the system, and ensure the accuracy of fault detection and the timeliness of protection action.

[0025] (6) Iterative optimization algorithm The protection setting value calculation method in the prior art lacks an iterative optimization mechanism, resulting in insufficient accuracy and reliability of the setting value. In the protection setting value calculation module, an iterative optimization algorithm is used to gradually optimize the protection setting value to ensure that it converges to a stable value. The algorithm gradually optimizes the protection setting value through multiple iterations to ensure that it can achieve the best effect under different fault conditions. The accuracy of the protection setting value is improved, and the reliability and selectivity of the protection action are ensured. Especially under complex fault conditions, the accuracy and reliability of the protection setting value can be ensured through multiple iterative optimizations, which improves the overall performance of the system and ensures the reliability and selectivity of the protection action.

[0026] (7) Multi-module collaborative work The problem of insufficient overall system performance and reliability due to the lack of effective data flow and information sharing between the modules of the protection system in the prior art is addressed. Through the close connection and collaborative work between the adaptive quick-break current protection module, the composite sequence network diagram analysis module, the fault current correction module and the protection setting value calculation module. This technology ensures data flow and information sharing between the modules through high-speed communication networks and data verification technology, thereby improving the overall system performance and reliability. It ensures data flow and information sharing between the modules, thereby improving the overall system performance and reliability. Especially under complex fault conditions, the collaborative work of multiple modules can achieve accurate identification and rapid response to faults, ensuring the stability and reliability of the system and improving the overall system performance and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of the power system distribution network complex fault analysis and protection setting calculation system provided in this embodiment.

[0028] Figure 2 A flow chart of the complex fault analysis and protection setting calculation method for the power system distribution network provided in this embodiment.

[0029] Reference numerals: 10-adaptive quick-break current protection module; 20-composite sequence network diagram analysis module; 30-fault current correction module; 40-protection setting value calculation module. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Embodiment 1: like Figure 1 As shown, a power system distribution network complex fault analysis and protection setting calculation system includes: The adaptive quick-break current protection module 10 is configured to obtain the operation status monitoring data of the distribution network, determine the protection setting value based on the operation status monitoring data, and use the protection setting value to perform protection actions of the distribution network for different fault types; The composite sequence network diagram analysis module 20 is configured to obtain feeder-related parameters of the distribution network, construct a composite sequence network diagram of the distribution network, perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, and generate a voltage and current distribution result of a fault point of the distribution network; The fault current correction module 30 receives the operation status monitoring data and the voltage and current distribution result of the fault point, and is configured to correct the fault current by using a dynamic excitation response correction algorithm based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network to obtain a fault current correction result; The protection setting value calculation module 40 receives the operation status monitoring data, the voltage and current distribution results of the fault point and the fault current correction results, and is configured to calculate the protection setting value of each branch using an adaptive multi-spectrum setting value optimization algorithm.

[0032] In this embodiment, a novel power system distribution network complex fault analysis and protection setting calculation system and method are proposed, which consists of an adaptive quick-break current protection module 10, a composite sequence network diagram analysis module 20, a fault current correction module 30 and a protection setting value calculation module 40. Among them, the adaptive quick-break current protection module 10 dynamically adjusts the protection setting value by real-time monitoring of the distribution network operation status to achieve rapid response to different types of faults; the composite sequence network diagram analysis module 20 uses the equivalent model of positive sequence, negative sequence and zero sequence impedance, comprehensively considers the influence of each line and load, and accurately calculates the voltage and current distribution of the fault point; the fault current correction module 30 combines the characteristics of the new energy unit, corrects the fault current through an iterative algorithm, and improves the accuracy of fault analysis; the protection setting value calculation module 40 provides accurate protection setting values ​​for each branch based on the above analysis results to ensure the reliability and effectiveness of the protection action. These modules are interconnected and together form an efficient and reliable distribution network complex fault analysis and protection setting calculation system, which can improve the scenario adaptability and analysis efficiency of complex fault analysis in the power system distribution network, ensure the stability and reliability of the distribution network, and improve the response speed of the power system and the accuracy of protection setting calculation.

[0033] (1) For the adaptive quick-break current protection module 10: The adaptive quick-break current protection module 10 monitors the operating status of the distribution network in real time and dynamically adjusts the protection setting to achieve rapid response to different types of faults. The design of this module fully considers the complexity and uncertainty of the distribution network containing new energy, especially under multi-point faults and short line conditions, and can effectively improve the selectivity and sensitivity of protection. The module consists of a data acquisition unit, a fault detection unit, a setting calculation unit and a protection execution unit, and each part is interconnected. Specifically, the working process of the adaptive quick-break current protection module 10 is as follows: The data acquisition unit collects the current and voltage data of the distribution network in real time through high-precision current transformers and voltage transformers installed in each branch. These data are transmitted to the fault detection unit through a high-speed communication network. In order to ensure the accuracy and real-time nature of the data, the data acquisition unit uses high-precision sensors and high-speed communication technology to ensure reliable data transmission. The fault detection unit receives real-time data from the data acquisition unit and uses a dynamic multi-spectrum fault detection algorithm to quickly identify the fault type and location based on the following mathematical model: ; in, Indicates that a branch is at time The current, is the DC component, It is The amplitude of the subharmonics, is the fundamental frequency, It is Phase angle of subharmonics. Through Fourier transform, the current signal can be decomposed into fundamental wave and each subharmonic component, so as to extract fault characteristics. The fault detection unit uses these characteristics and combines them with the preset fault judgment criteria to quickly identify the fault type and location.

[0034] After the fault detection is completed, the setting value calculation unit dynamically adjusts the protection setting value according to the fault detection result. The setting value calculation unit is based on the following formula: ; in, Indicates at time The protection value of is the basic value, and are the maximum current and minimum current at the current moment, is the adjustment factor. The value of is dynamically adjusted according to the actual operating status and fault type of the distribution network to ensure the rationality and effectiveness of the protection setting.

[0035] Specifically, the adjustment factor It can be calculated by the following formula: ; in, is the fault current, This is the current during normal operation. In this way, it can be ensured that the protection setting value can be dynamically adjusted under different fault conditions to improve the selectivity and sensitivity of the protection.

[0036] The protection execution unit performs the corresponding protection action according to the adjusted protection setting. When the detected current exceeds the protection setting, the protection execution unit immediately issues a trip command to quickly remove the fault. In order to ensure the reliability and selectivity of the protection action, the protection execution unit is also equipped with multiple protection mechanisms, such as backup protection and reclosing functions, to cope with various complex fault conditions.

[0037] Through the above design, the adaptive quick-break current protection module 10 can effectively solve the problems of poor adaptability, insufficient sensitivity and selectivity in the prior art. Especially in the distribution network containing new energy, the module can monitor and respond to various faults in real time to ensure the stability and reliability of the system. Compared with the traditional three-stage protection method, the adaptive quick-break current protection module 10 has a higher level of intelligence and stronger adaptive ability, and can better cope with the protection needs under complex fault conditions.

[0038] (2) For the composite sequence network diagram analysis module 20: The composite sequence network diagram analysis module 20 comprehensively considers the influence of positive sequence, negative sequence and zero sequence impedance, accurately calculates the voltage and current distribution of the fault point, and improves the accuracy of fault analysis. The design of this module fully considers the complexity and uncertainty of the distribution network containing new energy, especially under the conditions of multi-point faults and short lines, which can effectively improve the accuracy of fault analysis and provide a reliable basis for the calculation of protection setting values. The module consists of a system parameter input unit, a composite sequence network diagram construction unit, a fault analysis unit and a result output unit.

[0039] The system parameter input unit is responsible for collecting and inputting information such as line parameters, load parameters, fault point location, fault phase, negative sequence impedance and access location of each feeder of the distribution network. These parameters are transmitted to the composite sequence network diagram construction unit through a high-speed communication network. In order to ensure the accuracy and integrity of the data, the system parameter input unit uses high-precision measurement equipment and data verification technology to ensure the reliability of the input data.

[0040] The composite sequence network diagram construction unit receives the parameter data from the system parameter input unit and constructs the composite sequence network diagram using the multi-spectrum composite sequence network diagram construction method based on the following mathematical model: ; in, represents the equivalent impedance, is the positive sequence impedance, is the negative sequence impedance, is the zero-sequence impedance. By equating the positive-sequence, negative-sequence, and zero-sequence impedances of each line and load into a composite sequence network diagram, the electrical characteristics of the distribution network can be fully reflected. Specifically, the construction process of the composite sequence network diagram is as follows: 1. Positive sequence network: The positive sequence network represents the electrical characteristics of each branch under normal operating conditions. Positive sequence impedance Calculated by the following formula: ; in, is the positive sequence resistance, is the positive sequence reactance, Is an imaginary unit.

[0041] 2. Negative sequence network: Negative sequence network represents the electrical characteristics of each branch under symmetrical fault conditions. Negative sequence impedance Calculated by the following formula: ; in, is the negative sequence resistance, is the negative sequence reactance.

[0042] 3. Zero-sequence network: Zero-sequence network represents the electrical characteristics of each branch under asymmetric fault conditions. Zero-sequence impedance Calculated by the following formula: ; in, is the zero-sequence resistance, is the zero-sequence reactance.

[0043] By combining the positive-sequence, negative-sequence and zero-sequence networks to construct a composite sequence network diagram, the electrical characteristics of the distribution network under different fault conditions can be fully reflected.

[0044] The fault analysis unit uses a multi-spectrum fault analysis strategy based on the constructed composite sequence network diagram to perform fault analysis, which is achieved through the following steps: 1. Fault current calculation: Calculate the fault current of each branch according to the composite sequence network diagram. Calculated by the following formula: ; in, is the supply voltage, is the equivalent impedance.

[0045] 2. Fault point voltage calculation: Calculate the voltage at the fault point based on the fault current and the composite sequence network diagram. Calculated by the following formula: ; 3. Fault type judgment: judge the fault type according to the voltage and current distribution of the fault point. The fault type judgment is achieved through the following criteria: Single-phase grounding fault: voltage at fault point is the zero sequence voltage, fault current Mainly zero-sequence current.

[0046] Phase short circuit fault: Fault point voltage is the negative sequence voltage, the fault current Mainly negative sequence current.

[0047] Three-phase short circuit fault: voltage at fault point is the positive sequence voltage, the fault current Mainly positive sequence current.

[0048] Through the above steps, the fault analysis unit can accurately calculate the voltage and current distribution of the fault point, providing a reliable basis for the calculation of the protection setting value.

[0049] The result output unit outputs the result of the fault analysis to the protection setting value calculation module 40 for subsequent protection setting value calculation. The result output unit also provides a visual interface for users to view and analyze fault data. In order to ensure the accuracy and reliability of the results, the result output unit uses data verification and error analysis technology to ensure the accuracy of the output results.

[0050] Through the above design, the composite sequence network diagram analysis module 20 can effectively solve the problems of low model accuracy and poor adaptability in the prior art. Especially in the distribution network containing new energy, the module can fully consider the influence of positive sequence, negative sequence and zero sequence impedance, accurately calculate the voltage and current distribution of the fault point, and improve the accuracy of fault analysis. Compared with the traditional fault analysis method, the composite sequence network diagram analysis module 20 has a higher level of intelligence and stronger adaptive ability, and can better cope with the analysis needs under complex fault conditions.

[0051] (3) For the fault current correction module 30: The fault current correction module 30 dynamically corrects the fault current by combining the characteristics of the new energy unit, improves the accuracy of fault analysis, and provides a reliable basis for the calculation of the protection setting value. The design of this module fully considers the complexity and uncertainty of the distribution network containing new energy, especially under the conditions of multiple faults and short lines, which can effectively improve the accuracy of fault analysis and ensure the reliability and selectivity of protection action.

[0052] The fault current correction module 30 first receives the fault point voltage and current distribution data from the composite sequence network diagram analysis module 20, as well as the real-time operation status data of the adaptive quick-break current protection module 10. These data are transmitted to the fault current correction module 30 through a high-speed communication network to ensure the real-time and accuracy of the data. In order to ensure the integrity and reliability of the data, the fault current correction module 30 adopts high-precision data verification and error analysis technology.

[0053] The fault current correction module 30 uses a dynamic excitation response correction algorithm to correct the fault current. Based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network, it gradually corrects the fault current through iterative calculation to improve the accuracy of fault analysis. Specifically, the mathematical model of the DERA algorithm is as follows: 1. Calculation of initial fault current: First, the initial fault current of each branch is calculated based on the fault point voltage and current distribution data provided by the composite sequence network diagram analysis module 20. The initial fault current is calculated by the following formula: ; in, is the fault point voltage, is the equivalent impedance.

[0054] 2. Excitation response correction: Considering the excitation response characteristics of the new energy unit, the initial fault current is corrected. The excitation response correction is achieved through the following formula: ; in, is the corrected fault current, is the excitation response correction factor, Is the fault output current of the new energy unit. Excitation response correction coefficient Calculated by the following formula: ; in, is the excitation response time constant of the new energy unit, It is the maximum protection action time.

[0055] 3. Iterative correction: In order to further improve the accuracy of the fault current, the fault current correction module 30 adopts an iterative algorithm to gradually correct the fault current. The iterative correction is achieved by the following method: ; in, It is The fault current after iterations is It is The fault current after iterations is Iteration correction coefficient. Calculated by the following formula: ; The iteration process continues until the correction value of the fault current converges to a stable value. The convergence condition can be determined by the following formula: ; in, is the convergence threshold.

[0056] 4. Result output: After multiple iterations of correction, the fault current correction module 30 outputs the final fault current value to the protection setting value calculation module 40 for subsequent protection setting value calculation. The result output module also provides a visual interface for users to view and analyze fault current data. In order to ensure the accuracy and reliability of the results, the result output module uses data verification and error analysis technology to ensure the accuracy of the output results.

[0057] Through the above design, the fault current correction module 30 can effectively solve the problems of low model accuracy and poor adaptability existing in the prior art. Especially in the distribution network containing new energy, the module can dynamically correct the fault current and improve the accuracy of fault analysis in combination with the excitation response characteristics of the new energy unit. Compared with the traditional fault analysis method, the fault current correction module 30 has a higher level of intelligence and stronger adaptive ability, and can better cope with the analysis requirements under complex fault conditions. Through the close connection with the adaptive quick-break current protection module 10 and the composite sequence network diagram analysis module 20, the fault current correction module 30 provides a solid foundation for the fault analysis and protection of the entire system.

[0058] (4) For the protection setting value calculation module 40: The protection setting value calculation module 40 provides accurate protection setting values ​​for each branch by comprehensively considering the output results of the adaptive quick-break current protection module 10 and the fault current correction module 30, ensuring the reliability and selectivity of the protection action. The design of this module fully considers the complexity and uncertainty of the distribution network containing new energy sources, especially under multi-point faults and short line conditions, which can effectively improve the accuracy of the protection setting value and ensure the stability and reliability of the system. The protection setting value calculation module 40 is closely connected with the adaptive quick-break current protection module 10, the composite sequence network diagram analysis module 20 and the fault current correction module 30 to form an efficient and reliable fault analysis and protection system.

[0059] The protection setting value calculation module 40 first receives the real-time operation status data from the adaptive quick-break current protection module 10, the fault point voltage and current distribution data from the composite sequence network diagram analysis module 20, and the corrected fault current data from the fault current correction module 30. These data are transmitted to the protection setting value calculation module 40 through a high-speed communication network to ensure the real-time and accuracy of the data. In order to ensure the integrity and reliability of the data, the protection setting value calculation module 40 adopts high-precision data verification and error analysis technology.

[0060] The protection setting value calculation module 40 calculates the protection setting value of each branch using an adaptive multi-spectrum setting value optimization algorithm.

[0061] 1. Calculation of initial setting value: First, the initial protection setting value of each branch is calculated based on the voltage and current distribution data of the fault point provided by the composite sequence network diagram analysis module 20. Initial protection setting value Calculated by the following formula: ; in, is the initial protection setting value, is the basic value, and are the maximum current and minimum current at the current moment, is the initial adjustment factor. Initial adjustment factor Calculated by the following formula: ; in, is the current during normal operation.

[0062] 2. Fault current effect correction: Taking into account the corrected fault current provided by the fault current correction module 30, the initial setting value is corrected. The fault current effect correction is achieved by the following formula: ; in, is the corrected protection setting value, is the fault current correction factor, is the final fault current value of the fault current correction module 30. Fault current correction coefficient Calculated by the following formula: ; in, is a correction factor that can be set according to actual application requirements.

[0063] 3. Correction of operating status influence: Taking into account the real-time operating status data provided by the adaptive quick-break current protection module 10, the corrected setting value is further corrected. The operating status influence correction is achieved by the following formula: ; in, is the final protection setting value, is the operating status correction factor, It is the real-time current value provided by the adaptive quick-break current protection module 10. Operation status correction coefficient Calculated by the following formula: ; in, is the real-time monitoring cycle, It is the maximum protection action time.

[0064] 4. Iterative optimization: In order to further improve the accuracy of the protection setting value, the protection setting value calculation module 40 adopts an iterative optimization algorithm to gradually optimize the protection setting value. The iterative optimization is achieved through the following formula: ; in, It is The protection setting value after iterations is: It is The protection setting value after iterations is: It is the iterative optimization coefficient. Calculated by the following formula: ; The iteration process continues until the optimized value of the protection setting value converges to a stable value. The convergence condition can be determined by the following formula: ; in, It is the convergence threshold and can be set according to actual application requirements.

[0065] 5. Result output: After multiple iterations of optimization, the protection setting value calculation module 40 outputs the final protection setting value to the protection execution unit for subsequent protection actions. The result output module also provides a visual interface for users to view and analyze the protection setting value data. In order to ensure the accuracy and reliability of the results, the result output module uses data verification and error analysis technology to ensure the accuracy of the output results.

[0066] Through the above design, the protection setting value calculation module 40 can effectively solve the problems of poor adaptability, insufficient sensitivity and selectivity existing in the prior art. Especially in the distribution network containing new energy, the module can comprehensively consider the output results of the adaptive quick-break current protection module 10, the composite sequence network diagram analysis module 20 and the fault current correction module 30, dynamically adjust the protection setting value, and improve the reliability and selectivity of the protection action. Compared with the traditional protection setting value calculation method, the protection setting value calculation module 40 has a higher level of intelligence and stronger adaptability, and can better cope with the protection needs under complex fault conditions. Through close connection with other modules, the protection setting value calculation module 40 provides a solid foundation for fault analysis and protection of the entire system.

[0067] It should be noted that although the protection setting value calculation module 40 and the fault current correction module 30 both involve data processing and optimization, their functions and roles are significantly different: the fault current correction module 30 is mainly responsible for dynamically correcting the fault current in combination with the excitation response characteristics of the new energy unit to improve the accuracy of fault analysis. The output result of this module is the corrected fault current, which is used for subsequent protection setting value calculation. The protection setting value calculation module 40 is mainly responsible for comprehensively considering the output results of the adaptive quick-break current protection module 10, the composite sequence network diagram analysis module 20 and the fault current correction module 30, and calculating the protection setting value of each branch. The output result of this module is an accurate protection setting value, which is used to guide the action of the protection device.

[0068] Embodiment 2: Reference Figure 2 , Figure 2 A flow chart of a complex fault analysis and protection setting calculation method for a power system distribution network provided by an embodiment of the present invention.

[0069] like Figure 2 As shown, a complex fault analysis and protection setting calculation method for a power system distribution network is used for the complex fault analysis and protection setting calculation system for a power system distribution network as described above, comprising: S1: Acquire operation status monitoring data of the distribution network, determine a protection setting value based on the operation status monitoring data, and use the protection setting value to perform protection actions for different fault types of the distribution network; S2: Obtain feeder-related parameters of the distribution network, construct a composite sequence network diagram of the distribution network, perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, and generate voltage and current distribution results of fault points in the distribution network; S3: receiving the operation status monitoring data and the voltage and current distribution result of the fault point, and based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network, correcting the fault current by using a dynamic excitation response correction algorithm to obtain a fault current correction result; S4: receiving the operation status monitoring data, the voltage and current distribution results of the fault point and the fault current correction results, and calculating the protection setting value of each branch using an adaptive multi-spectrum setting value optimization algorithm.

[0070] The specific implementation method of the complex fault analysis and protection setting calculation method of the power system distribution network of the present application is basically the same as the above-mentioned complex fault analysis and protection setting calculation system embodiment of the power system distribution network, and will not be repeated here.

[0071] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "top", "bottom", "inside", "outside", "inner side", "outer side" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Among them, "inside" refers to an internal or enclosed area or space. "Periphery" refers to the area surrounding a specific component or a specific area.

[0072] In the description of the embodiments of the present invention, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0073] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", and "assemble" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] In the description of the embodiments of the present invention, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0075] In the description of the embodiments of the present invention, it should be understood that "-" and "~" represent a range between two values, and the range includes the endpoints. For example: "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0076] In the description of the embodiments of the present invention, the term "and / or" herein is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein generally indicates that the associated objects before and after are in an "or" relationship.

[0077] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A power system distribution network complex fault analysis and protection setting calculation system, characterized in that: include: An adaptive quick-break current protection module is configured to obtain operation status monitoring data of the distribution network, determine a protection setting value based on the operation status monitoring data, and use the protection setting value to perform protection actions of the distribution network for different fault types; A composite sequence network diagram analysis module is configured to obtain feeder-related parameters of the distribution network, construct a composite sequence network diagram of the distribution network, perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, and generate a voltage and current distribution result of a fault point of the distribution network; A fault current correction module receives the operation status monitoring data and the voltage and current distribution result of the fault point, and is configured to correct the fault current by using a dynamic excitation response correction algorithm based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network to obtain a fault current correction result; The protection setting value calculation module receives the operation status monitoring data, the voltage and current distribution results of the fault point and the fault current correction result, and is configured to calculate the protection setting value of each branch using an adaptive multi-spectrum setting value optimization algorithm.

2. The power system distribution network complex fault analysis and protection setting calculation system according to claim 1 is characterized in that: The adaptive quick-break current protection module specifically includes: The data acquisition unit is configured to collect current data and voltage data of the distribution network in real time through current transformers and voltage transformers installed in each branch, and output the current data and voltage data as operation status monitoring data; a fault detection unit configured to receive the real-time data collected by the data collection unit and to quickly identify the fault type and location of the distribution network using a dynamic multi-spectrum fault detection algorithm; A set value calculation unit is configured to generate protection set values ​​for dynamic adjustment of the distribution network under different fault conditions according to the fault detection result; The protection execution unit is configured to execute protection actions of the distribution network for different fault types according to the protection setting.

3. The power system distribution network complex fault analysis and protection setting calculation system according to claim 2 is characterized in that: The dynamic multi-spectral fault detection algorithm is used to quickly identify the fault type and location of the distribution network, including: Through Fourier transform, the current data of the distribution network is decomposed into fundamental wave and harmonic components to construct fault features. The constructed fault features are combined with preset fault judgment criteria to identify the fault type and location of the distribution network. The expression for constructing fault characteristics by decomposing the current data of the distribution network into fundamental wave and harmonic components is specifically: ； In the formula, Indicates that a branch is at time The current, is the DC component, It is The amplitude of the subharmonics, is the fundamental frequency, It is The phase angle of the subharmonic.

4. The power system distribution network complex fault analysis and protection setting calculation system according to claim 2 is characterized in that: Generate the expression of protection setting value for dynamic adjustment of distribution network under different fault conditions, specifically: ； ； in, Indicates at time The protection value of Indicates the basic value, and are the maximum current and minimum current at the current moment, is the adjustment factor, is the fault current, is the current during normal operation.

5. The power system distribution network complex fault analysis and protection setting calculation system according to claim 1 is characterized in that: The composite sequence network diagram analysis module specifically includes: The system parameter input unit is configured to obtain feeder-related parameters of the distribution network; wherein the feeder-related parameters include line parameters, load parameters, fault point location, fault phase, negative sequence impedance and access location of each feeder of the distribution network; A composite sequence network diagram construction unit is configured to construct a composite sequence network diagram of the distribution network based on the received feeder-related parameters of the distribution network and the equivalent relationship between the positive sequence, negative sequence and zero sequence impedances of each line and the load; A fault analysis unit is configured to perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, perform fault current calculation, fault point voltage calculation and fault type judgment of the distribution network, and generate a voltage and current distribution result of the fault point of the distribution network; The result output unit is configured to transmit the generated voltage and current distribution results of the fault point of the distribution network to the protection setting value calculation module and provide a fault visualization interface.

6. The power system distribution network complex fault analysis and protection setting calculation system according to claim 5 is characterized in that: Based on the equivalent relationship between the positive sequence, negative sequence and zero sequence impedance of each line and load, a composite sequence network diagram of the distribution network is constructed, including: Based on the positive-sequence, negative-sequence and zero-sequence impedances of each line and load, a multi-spectrum composite sequence network diagram construction method is used to integrate the positive-sequence, negative-sequence and zero-sequence networks with the equivalent impedance mathematical calculation model of the positive-sequence, negative-sequence and zero-sequence impedances of the load to construct a composite sequence network diagram; Among them, the expression of the equivalent impedance mathematical calculation model is specifically: ； ； ； ； in, represents the equivalent impedance, is the positive sequence impedance, is the negative sequence impedance, is the zero-sequence impedance, is the positive sequence resistance, is the positive sequence reactance, is an imaginary unit, is the negative sequence resistance, is the negative sequence reactance, is the zero-sequence resistance, is the zero-sequence reactance.

7. The power system distribution network complex fault analysis and protection setting calculation system according to claim 6 is characterized in that: Perform fault current calculation, fault point voltage calculation and fault type judgment of the distribution network, including: According to the composite sequence network diagram, calculate the fault current of each branch, and calculate the voltage of the fault point according to the fault current and the composite sequence network diagram; determine the fault type according to the voltage and current distribution of the fault point; Among them, the expressions of fault current and fault point voltage are as follows: ； ； In the formula, is the fault current, is the supply voltage, is the equivalent impedance, is the fault point voltage; Among them, the criteria for determining the fault type are specifically: Single-phase grounding: Fault point voltage is the zero sequence voltage, fault current is the zero-sequence current; phase-to-phase short circuit: fault point voltage is the negative sequence voltage, the fault current Negative sequence current; three-phase short circuit: fault point voltage is the positive sequence voltage, the fault current is the positive sequence current.

8. The power system distribution network complex fault analysis and protection setting calculation system according to claim 1 is characterized in that: Based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network, the dynamic excitation response correction algorithm is used to correct the fault current and obtain the fault current correction result, which includes: According to the fault point voltage and current distribution data provided by the composite sequence network diagram analysis module, the initial fault current of each branch is calculated. Considering the excitation response characteristics of the new energy unit, the initial fault current is corrected by excitation response. The iterative algorithm is used to gradually correct the fault current. After multiple iterative corrections, the final fault current value is output to the protection setting value calculation module; Among them, the calculation expression of the initial fault current is as follows: ； In the formula, is the fault point voltage, is the equivalent impedance; Among them, the calculation expression of excitation response correction is as follows: ； In the formula, is the corrected fault current, is the excitation response correction factor, is the fault output current of the new energy unit, the excitation response correction coefficient Calculated by the following formula: ； In the formula, is the excitation response time constant of the new energy unit, is the maximum protection action time; Among them, the expression of corrected fault current is: ； In the formula, It is The fault current after iterations is It is The fault current after iterations is is the iteration correction coefficient, the iteration correction coefficient Calculated by the following formula: ； The iteration process continues until the correction value of the fault current converges to a stable value. The convergence condition is determined by the following formula: ； In the formula, is the convergence threshold.

9. The power system distribution network complex fault analysis and protection setting calculation system according to claim 1, characterized in that: The adaptive multi-spectrum setting value optimization algorithm is used to calculate the protection setting value of each branch, including: Calculate the initial protection setting value of each branch according to the voltage and current distribution result of the fault point, consider the fault current correction result, make a first correction to the initial setting value, consider the operation status monitoring data, make a second correction to the initial setting value after the first correction, adopt an iterative optimization algorithm, gradually optimize the protection setting value, and output the protection setting value after multiple iterations of optimization as the final protection setting value; Among them, the expression for calculating the initial protection setting value of each branch is as follows: ； ； In the formula, is the initial protection setting value, is the basic value, and are the maximum current and minimum current at the current moment, is the initial adjustment factor, is the current during normal operation; Among them, the expression for the first correction of the initial setting value is as follows: ； ； In the formula, is the corrected protection setting value, is the fault current correction factor, is the final fault current value of the fault current correction module, is a correction factor, which is set according to actual application requirements; Among them, the expression for the second correction of the initial setting value is as follows: ； ； In the formula, is the final protection setting value, is the operating status correction factor, It is the real-time current value provided by the adaptive fast-break current protection module. is the real-time monitoring cycle, is the maximum protection action time; Among them, the iterative optimization algorithm gradually optimizes the expression of the protection setting value, which is specifically: ； ； In the formula, It is The protection setting value after iterations is: It is The protection setting value after iterations is: is the iterative optimization coefficient; the iteration process continues until the optimized value of the protection setting value converges to a stable value. The convergence condition is determined by the following formula: ； in, It is the convergence threshold and can be set according to actual application requirements.

10. A method for complex fault analysis and protection setting calculation of power system distribution network, characterized in that: The method comprises: S1: Acquire operation status monitoring data of the distribution network, determine a protection setting value based on the operation status monitoring data, and use the protection setting value to perform protection actions for different fault types of the distribution network; S2: Obtain feeder-related parameters of the distribution network, construct a composite sequence network diagram of the distribution network, perform distribution network fault analysis on the composite sequence network diagram using a multi-spectrum fault analysis strategy, and generate voltage and current distribution results of fault points in the distribution network; S3: receiving the operation status monitoring data and the voltage and current distribution result of the fault point, and based on the excitation response characteristics of the new energy unit and the electrical characteristics of the distribution network, correcting the fault current by using a dynamic excitation response correction algorithm to obtain a fault current correction result; S4: receiving the operation status monitoring data, the voltage and current distribution results of the fault point and the fault current correction results, and calculating the protection setting value of each branch using an adaptive multi-spectrum setting value optimization algorithm.

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