Power distribution network feeder automation terminal traveling wave distance measurement method and system

Abstract

The application discloses a kind of power distribution network feeder automation terminal travelling wave distance measurement method and system, it is related to travelling wave distance measurement technical field, including: to the impulse signal test of feeder automation terminal, obtain the farthest reliable distance of terminal ranging, obtain the key node in distribution network, install feeder automation terminal in distribution network line;Distribution network is divided into several sub-sections, collect travelling wave data in fault time, determine the target section where fault point is;Obtain the terminal position and section length corresponding to target section, obtain the position where fault point is, output fault point geographic coordinate information, complete distribution network fault location.The application provides more reliable, more adaptive distribution network scene travelling wave distance measurement scheme by signal matching instead of clock synchronization and topological constraint auxiliary feature recognition design, effectively overcome the defects of traditional travelling wave distance measurement, with stronger environmental adaptability and result accuracy.

Description

Technical Field

[0001] This invention relates to the field of traveling wave ranging technology, specifically a traveling wave ranging method and system for automated terminals of power distribution network feeders. Background Technology

[0002] As the final link in the power system, the distribution network directly connects to a large number of power users. Its operational reliability is closely related to power supply quality, and line faults are one of the main causes of power outages in the distribution network. Quickly and accurately locating fault points is a key technical aspect for shortening fault repair time, reducing the scope of power outages, and improving power supply reliability. Traditional fault location methods mainly rely on impedance methods and manual line inspection. However, impedance methods are easily affected by factors such as asymmetrical line parameters, transition resistance, and changes in system operating modes, resulting in limited accuracy in complex distribution networks and unsatisfactory practical application effects. Manual line inspection is inefficient, especially in harsh environments or at night, and is time-consuming. Therefore, it is necessary to develop a precise and automatic fault location technology adapted to the characteristics of the distribution network to facilitate the intelligent operation and maintenance upgrade of the power industry. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for measuring traveling wave distance in automated terminals of power distribution network feeders, so as to solve the problems raised in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for measuring traveling wave distance in an automated terminal unit of a distribution network feeder includes the following steps: Pulse signal tests are performed on the feeder automation terminals deployed in the distribution network to obtain the farthest reliable distance for terminal ranging, the distribution network line topology is obtained, and the key nodes in the distribution network are obtained according to the line connection relationship. Based on the farthest reliable distance and key nodes, the feeder automation terminals can be installed on the distribution network lines. In this solution, the farthest reliable distance must first be identified. This farthest reliable distance serves as the core constraint for terminal deployment and is used to determine the farthest distance between adjacent terminals. This avoids excessive deviations in fault location calculation results due to excessively large terminal spacing or distances between terminals and fault points exceeding the reliable range, thereby ensuring the reliability and accuracy of the location results.

[0005] Based on the terminal location, the distribution network is divided into several sub-segments; when a fault occurs in the distribution network, all terminals collect traveling wave data during the fault time according to a preset sampling time interval, and the target segment where the fault point is located is determined based on the traveling wave data of each terminal. Obtain the terminal location and segment length corresponding to the target segment, and determine the location of the fault point based on the traveling wave data of the terminal; output the obtained geographical coordinate information of the fault point to complete the fault location of the distribution network.

[0006] Preferably, the installation of feeder automation terminals on distribution network lines includes: Obtain a faulty line segment, deploy terminals at different locations away from the faulty line, and transmit test traveling wave signals to the faulty line starting from the faulty location, capturing the time when the faulty traveling wave arrives at the terminal during each test. The lines in the distribution network are three-phase lines. Three-phase lines are three phase lines used to transmit three-phase AC power in a medium-voltage distribution network. The voltage and current on the three lines have the same frequency, equal amplitude, and a phase difference of 120°. They are the main body of power transmission in the distribution network. When a fault occurs, the current of one or more phases will suddenly change, generating a voltage transient traveling wave. The voltage transient waveform refers to the instantaneous voltage waveform that changes rapidly and deviates from the normal power frequency sine wave in a very short time when a fault, lightning strike, or disturbance occurs in the distribution network line. The traveling wave signal in this scheme is the voltage waveform that represents this.

[0007] Obtain the traveling wave velocity V of the traveling wave signal. Based on the distance L between the terminal and the fault point during a certain test, and the duration D between the start of the test and the arrival time of the fault band at the terminal, the deviation value of this test is obtained as Y = 1 - e -|VD-L| Extract the distance and deviation values ​​corresponding to several tests, establish a scatter plot of distance values ​​as a function of deviation values, and obtain the farthest reliable distance of terminal ranging based on the scatter plot; Install feeder automation terminals at key nodes in the distribution network. Key nodes are the nodes where distribution network lines are interconnected. If the length of a line in the distribution network exceeds the maximum reliable distance, add a terminal at the middle position of the line according to the connection relationship and line topology of the distribution network.

[0008] It should be noted that in sections with many branches and a large number of lines connected by those branches, the traveling wave will be reflected, superimposed, and deformed when it reaches the branch, and the wavefront will become smoother and blunter. Only with more refined sampling can the blurred wavefront details be captured; otherwise, the identification will fail or be incorrect. Therefore, it is necessary to set the condition of deploying terminals closer to the end with a larger target value and shorter distances between adjacent terminals. Conversely, the same applies to sections with simple structures and few branches.

[0009] Preferably, the farthest reliable distance for obtaining terminal ranging includes: Set the deviation threshold to Y0, and mark the scatter points with deviation values ​​greater than Y0 as deviation points; Set the ratio threshold to R, and iterate through the scatter plot in ascending order of distance values. The distance value that first satisfies the condition that the proportion of the number of deviation points to the total number of scatter points exceeds R is taken as the farthest reliable distance.

[0010] Preferably, a deployment terminal is added at the middle of the line, including: The line whose length exceeds the longest reliable distance is selected as the analysis line, and the starting position P of the analysis line is obtained. H and end position P E ; Obtain all lines and key nodes in the distribution network, and determine the location of each key node relative to its starting point P. H The distance between them is used to set the first weight of each key node according to the rule that the smaller the distance, the larger the first weight, and the sum of the first weights is 1. Obtain the position P of the first end H Target value: Q represents the number of critical nodes in the distribution network, and W represents the number of critical nodes in the distribution network. q Let G be the first weight of the q-th key node. q The number of line segments connected to the q-th critical node; Analogy to the first position P H The target value is calculated using the method to obtain the end position P. E The target value; when adding terminals in the middle of the analysis line, the deployment should follow the rule that the closer to the end with the larger target value, the shorter the distance between two adjacent terminals, and the distance between any two adjacent terminals is less than the farthest reliable distance.

[0011] Preferably, determining the target section where the fault point is located includes: Obtain the deployment location of all terminals in the distribution network, take the line segment between two adjacent terminals as a sub-segment, and traverse to obtain all sub-segments in the distribution network; Obtain the start position P1, end position P2, and length S of sub-segment K. K When a fault occurs in the distribution network, the traveling wave data captured by a terminal A deployed at the beginning position P1 and a terminal B deployed at the end position P2 are extracted respectively. The traveling wave data is analyzed to obtain the time difference Δt_AB between the fault traveling wave and the two terminals. Since the traveling wave data corresponding to terminal A and terminal B capture the signals of the same physical event propagating to different locations, the similarity between the two fault traveling wave functions corresponding to the signals should be relatively large in order to ensure that the information collected is the corresponding information of the same fault point. The time difference Δt_AB represents the precise time difference between the arrival of the fault traveling wave at the two terminals.

[0012] Obtain the distance S between terminal A and the starting position P1. A1 And the distance S between terminal B and end position P2 B2 According to the traveling wave velocity V, if the following condition is met: Δt_AB is... and If the sub-segment K is between the two terminals, then the sub-segment K is taken as the segment to be determined. Extract the traveling wave data captured by any sub-segment and any two terminals, and perform traversal calculation. If only the sub-segment K is determined as the segment to be determined in each traversal, then the sub-segment K is determined as the target segment.

[0013] Preferably, the traveling wave data is analyzed to obtain the time difference Δt_AB between the arrival times of the fault traveling wave at the two terminals, including: A fault traveling wave is a traveling wave signal whose traveling wave band exceeds the preset band threshold. Set a traveling wave acquisition time window, and extract the fault traveling wave function within the time window from the traveling wave data corresponding to terminal A and terminal B respectively. The fault traveling wave function is a function of the amplitude of the traveling wave band changing with time. Calculate the similarity between the two fault traveling wave functions. If the similarity is greater than a preset similarity threshold, it is determined that the traveling waves captured by terminal A and terminal B are valid traveling waves caused by the same fault. Obtain the time T when terminal A starts receiving the fault band. A The time T when terminal B begins receiving the faulty band. B The time difference Δt_AB is obtained.

[0014] Preferably, the location of the fault point is obtained, including: Obtain the terminal M at the beginning of the target segment, the terminal N at the end of the target segment, and the segment length S. Based on the traveling wave data captured by terminals M and N, obtain the time difference Δt_MN between the arrival times of the fault traveling wave at the two terminals. Based on the traveling wave velocity V, use the formula: Calculate the fault distance X; the fault point is located on the target section at a distance X from the beginning and SX from the end.

[0015] A traveling wave ranging system for automated terminals of distribution network feeders includes a terminal deployment module, a target section determination module, and a fault location module; Terminal deployment module: used to perform pulse signal testing on feeder automation terminals deployed in the distribution network, obtain the farthest reliable distance of terminal ranging, obtain the distribution network line topology, and obtain the key nodes in the distribution network according to the line connection relationship. Based on the farthest reliable distance and key nodes, the feeder automation terminals can be installed on the distribution network lines. Target section determination module: used to divide the distribution network into several sub-sections according to the terminal location; when a fault occurs in the distribution network, all terminals collect traveling wave data during the fault time according to a preset sampling time interval, and determine the target section where the fault point is located based on the traveling wave data of each terminal. Fault location module: used to obtain the terminal location and section length corresponding to the target section, and obtain the location of the fault point based on the traveling wave data of the terminal; output the obtained geographical coordinate information of the fault point to complete the fault location of the distribution network.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a traveling wave ranging method and system for distribution network feeder automation terminals, comprising: performing pulse signal testing on the feeder automation terminal to obtain the farthest reliable distance for terminal ranging; acquiring the distribution network line topology to identify key nodes in the distribution network; installing the feeder automation terminal on the distribution network line; dividing the distribution network into several sub-segments; collecting traveling wave data during the fault time to determine the target segment where the fault point is located; acquiring the terminal position and segment length corresponding to the target segment to obtain the location of the fault point; outputting the geographical coordinate information of the fault point to complete the distribution network fault location. This invention, through the design of replacing clock synchronization with signal matching and using topological constraints to assist feature identification, provides a more reliable and adaptable traveling wave ranging scheme for distribution network scenarios, effectively overcoming the shortcomings of traditional traveling wave ranging, and exhibiting stronger environmental adaptability and result accuracy. Attached Figure Description

[0017] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating a traveling wave ranging method for automated terminals of power distribution network feeders according to the present invention. Detailed Implementation

[0019] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0020] Example: Figure 1 As shown, this invention provides a technical solution for a traveling wave ranging method for automated terminals of distribution network feeders, comprising the following steps: Pulse signal tests are performed on the feeder automation terminals deployed in the distribution network to obtain the farthest reliable distance for terminal ranging, and the distribution network line topology is obtained. Based on the line connection relationships, the key nodes in the distribution network are identified. Based on the farthest reliable distance and the key nodes, the feeder automation terminals are installed on the distribution network lines, specifically as follows: Obtain a faulty line segment, deploy terminals at different locations away from the faulty line, and transmit test traveling wave signals to the faulty line starting from the faulty location, capturing the time when the faulty traveling wave arrives at the terminal during each test. The lines in the distribution network are three-phase lines. Three-phase lines are three phase lines used to transmit three-phase AC power in a medium-voltage distribution network. The voltage and current on the three lines have the same frequency, equal amplitude, and a phase difference of 120°. They are the main body of power transmission in the distribution network. When a fault occurs, the current of one or more phases will suddenly change, generating a voltage transient traveling wave. The voltage transient waveform refers to the instantaneous voltage waveform that changes rapidly and deviates from the normal power frequency sine wave in a very short time when a fault, lightning strike, or disturbance occurs in the distribution network line. The traveling wave signal in this scheme is the voltage waveform that represents this.

[0021] Obtain the traveling wave velocity V of the traveling wave signal. Based on the distance L between the terminal and the fault point during a certain test, and the duration D between the start of the test and the arrival time of the fault band at the terminal, the deviation value of this test is obtained as Y = 1 - e -|VD-L| Extract the distance and deviation values ​​corresponding to several tests, and establish a scatter plot of distance values ​​as a function of deviation values.

[0022] Formula g = 1 - e -z When z is greater than 0, g takes the value of a function from 0 to 1, and g increases with the increase of z. In this scheme, |VD-L| represents the degree of deviation between the fault location obtained by the terminal test and the actual location. The larger the value, the greater the deviation of the terminal test. Therefore, in this scheme, the deviation value Y can be used to represent the deviation of the terminal test under different conditions. In the process of fault location in the distribution network, the deviation value Y usually shows a significant positive correlation with the distance between the terminal and the fault point. The farther the distance between the terminal and the fault point, the more obvious the attenuation of the traveling wave signal during propagation, the greater the error of wavefront identification, and ultimately the larger the deviation value Y. Therefore, in this scheme, it is necessary to first find the farthest reliable distance. This farthest reliable distance is used as the core constraint condition for terminal deployment to determine the farthest distance between adjacent terminals, thereby avoiding excessive deviation values ​​in the fault location calculation results due to excessively large terminal spacing or the distance between the terminal and the fault point exceeding the reliable range, thus ensuring the reliability and accuracy of the location results.

[0023] Set the deviation threshold to Y0, and mark the scatter points with deviation values ​​greater than Y0 as deviation points; Set the ratio threshold to R, and iterate through the scatter plot in ascending order of distance values. The distance value that first satisfies the condition that the proportion of the number of deviation points to the total number of scatter points exceeds R is taken as the farthest reliable distance. In this embodiment, R is 15%. That is, when more than 15% of the scatter points that are less than or equal to a certain distance value are deviation points, that certain distance value is taken as the farthest reliable distance.

[0024] Feeder automation terminals are installed at key nodes in the distribution network. Key nodes are the interconnections between distribution network lines, specifically including: the starting point of the main line, the connection point between the main line and a branch line, the end point of a branch line, etc. If the length of a line in the distribution network exceeds the maximum reliable distance, terminals are added and deployed at intermediate locations along that line, based on the network's connection relationships and topology. The line whose length exceeds the longest reliable distance is selected as the analysis line, and the starting position P of the analysis line is obtained. H and end position P E ; Obtain all lines and key nodes in the distribution network, and determine the location of each key node relative to its starting point P. H The distance between them is used to set the first weight of each key node according to the rule that the smaller the distance, the larger the first weight, and the sum of the first weights is 1. Obtain the position P of the first end H Target value: Q represents the number of critical nodes in the distribution network, and W represents the number of critical nodes in the distribution network. q Let G be the first weight of the q-th key node. q The number of line segments connected to the q-th critical node.

[0025] Analogy to the first position P H The target value is calculated using the method to obtain the end position P. E The target value is specifically: based on each key node and the end position P. E The second weight of each key node is set according to the rule that the smaller the distance, the larger the second weight, and the sum of the second weights is 1. Obtain the end position P E Target value: Q represents the number of critical nodes in the distribution network, and C represents the number of critical nodes in the distribution network. q G is the second weight of the q-th key node. q The number of line segments connected to the q-th critical node.

[0026] When adding terminals in the middle of the line, the deployment should follow the rule that the closer to the end with the larger target value, the shorter the distance between two adjacent terminals, and the distance between any two adjacent terminals is less than the farthest reliable distance.

[0027] It should be noted that in sections with many branches and a large number of lines connected by those branches, the traveling wave will reflect, superimpose, and deform when it reaches the branch, causing the wavefront to become gentler and blunter (characterized by a target value in this scheme, which is quantified based on the number of lines connected to the branch). Only with more refined sampling can the blurred wavefront details be captured; otherwise, recognition will fail or be incorrect. Therefore, it is necessary to set the condition of deploying terminals closer to the end with a larger target value and shorter distances between adjacent terminals. Conversely, the same applies to sections with simple structures and few branches.

[0028] Obtain the deployment location of all terminals in the distribution network, take the line segment between two adjacent terminals as a sub-segment, and traverse to obtain all sub-segments in the distribution network.

[0029] When a fault occurs in the distribution network, all terminals collect traveling wave data within the fault period according to a preset sampling time interval. Based on the traveling wave data of each terminal, the target section where the fault point is located is determined, specifically: Obtain the start position P1, end position P2, and length S of sub-segment K. K When a distribution network fault occurs, traveling wave data captured by terminal A (located at the beginning of the network, P1) and terminal B (located at the end of the network, P2) are extracted. The traveling wave data is analyzed to obtain the time difference Δt_AB between the arrival times of the fault traveling wave at the two terminals. Specifically: A fault traveling wave is a traveling wave signal whose traveling wave band exceeds the preset band threshold. Set a traveling wave acquisition time window, and extract the fault traveling wave function within the time window from the traveling wave data corresponding to terminal A and terminal B respectively. The fault traveling wave function is a function of the amplitude of the traveling wave band changing with time. Calculate the similarity between the two fault traveling wave functions. If the similarity is greater than a preset similarity threshold, it is determined that the traveling waves captured by terminal A and terminal B are valid traveling waves caused by the same fault. Obtain the time T when terminal A starts receiving the fault band. A The time T when terminal B begins receiving the faulty band. B The time difference Δt_AB is obtained.

[0030] Since the traveling wave data corresponding to terminal A and terminal B capture the signals of the same physical event propagating to different locations, the similarity between the two fault traveling wave functions corresponding to the signals should be relatively large in order to ensure that the information collected is the corresponding information of the same fault point. The time difference Δt_AB represents the precise time difference between the arrival of the fault traveling wave at the two terminals.

[0031] Obtain the distance S between terminal A and the starting position P1. A1 And the distance S between terminal B and end position P2 B2 According to the traveling wave velocity V, if the following condition is met: Δt_AB is... and If the sub-segment K is between the two terminals, then the sub-segment K is taken as the segment to be determined. Extract the traveling wave data captured by any sub-segment and any two terminals, and perform traversal calculation. If only the sub-segment K is determined as the segment to be determined in each traversal, then the sub-segment K is determined as the target segment.

[0032] The following example is given: Assume the length S of sub-segment K. K =150, the distance S between terminal A and the starting position P1 A1 =100, the distance S between terminal B and end position P2 B2 =200, traveling wave beam V is 150, Δt_AB=1, then the formula can be obtained. The value is (200+150-100) / 150=5 / 3, according to the formula. The value is (200-150-100) / 150=-1 / 3. At this time, since Δt_AB=1, and In other words, if sub-segment K satisfies the fault segment condition determined by terminal A and terminal B, then sub-segment K is designated as the segment to be determined. If only sub-segment K is determined as the segment to be determined in each traversal, then sub-segment K can be identified as the target segment where the fault occurs.

[0033] Obtain the terminal M at the beginning of the target segment, the terminal N at the end of the target segment, and the segment length S. Based on the traveling wave data captured by terminals M and N, obtain the time difference Δt_MN between the arrival times of the fault traveling wave at the two terminals. Based on the traveling wave velocity V, use the formula: Calculate the fault distance X; obtain the fault point as the distance from the beginning position X and the distance from the end position SX on the target section; output the obtained geographical coordinate information of the fault point to complete the fault location of the distribution network.

[0034] Compared with existing technologies, this invention utilizes the relative timing relationship formed by the natural arrival of the initial traveling wave at each monitoring point to replace absolute time synchronization. Combined with the distribution network topology and the multimodal characteristics of the traveling wave, a distributed and collaborative fault location method is constructed. This method has the advantages of not relying on a wide-area high-precision synchronous clock, effectively identifying fault reflection waves, and adapting to complex distribution network topologies. It significantly improves the accuracy and reliability of fault location under limited information conditions, and enhances the technical level and practical effect of distribution network feeder automation.

[0035] This embodiment also provides a distribution network feeder automation terminal traveling wave ranging system, including a terminal deployment module, a target section determination module, and a fault location module; Terminal deployment module: used to perform pulse signal testing on feeder automation terminals deployed in the distribution network, obtain the farthest reliable distance of terminal ranging, obtain the distribution network line topology, and obtain the key nodes in the distribution network according to the line connection relationship. Based on the farthest reliable distance and key nodes, the feeder automation terminals can be installed on the distribution network lines. Target section determination module: used to divide the distribution network into several sub-sections according to the terminal location; when a fault occurs in the distribution network, all terminals collect traveling wave data during the fault time according to a preset sampling time interval, and determine the target section where the fault point is located based on the traveling wave data of each terminal. Fault location module: used to obtain the terminal location and section length corresponding to the target section, and obtain the location of the fault point based on the traveling wave data of the terminal; output the obtained geographical coordinate information of the fault point to complete the fault location of the distribution network.

[0036] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0037] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for measuring the traveling wave distance of an automated terminal unit in a distribution network feeder, characterized in that, Includes the following steps: Pulse signal tests are performed on the feeder automation terminals deployed in the distribution network to obtain the farthest reliable distance for terminal ranging, the distribution network line topology is obtained, and the key nodes in the distribution network are obtained according to the line connection relationship. Based on the farthest reliable distance and key nodes, the feeder automation terminals can be installed on the distribution network lines. Based on the terminal location, the distribution network is divided into several sub-segments; when a fault occurs in the distribution network, all terminals collect traveling wave data during the fault time according to a preset sampling time interval, and the target segment where the fault point is located is determined based on the traveling wave data of each terminal. Obtain the terminal location and segment length corresponding to the target segment, and determine the location of the fault point based on the traveling wave data of the terminal. Output the obtained geographical coordinates of the fault point to complete the fault location in the power distribution network; Among them, the installation of feeder automation terminals on distribution network lines includes: Obtain a faulty line segment, deploy terminals at different locations away from the faulty line, and transmit test traveling wave signals to the faulty line starting from the faulty location, capturing the time when the faulty traveling wave arrives at the terminal during each test. Obtain the traveling wave velocity V of the traveling wave signal. Based on the distance L between the terminal and the fault point during a certain test, and the duration D between the start of the test and the arrival time of the fault band at the terminal, the deviation value of this test is obtained as Y = 1 - e -|VD-L| Extract the distance and deviation values ​​corresponding to several tests, establish a scatter plot of distance values ​​as a function of deviation values, and obtain the farthest reliable distance of terminal ranging based on the scatter plot; Install feeder automation terminals at key nodes in the distribution network. The key nodes are the nodes where distribution network lines are interconnected. If the length of a line in the distribution network exceeds the maximum reliable distance, a terminal is added and deployed in the middle of the line according to the connection relationship and topology of the distribution network lines.

2. The method for traveling wave ranging of a distribution network feeder automation terminal according to claim 1, characterized in that, The farthest reliable distance for terminal ranging is obtained, including: Set the deviation threshold to Y0, and mark the scatter points with deviation values ​​greater than Y0 as deviation points; Set the ratio threshold to R, and iterate through the scatter plot in ascending order of distance values. The distance value that first satisfies the condition that the proportion of the number of deviation points to the total number of scatter points exceeds R is taken as the farthest reliable distance.

3. The method for traveling wave ranging of a distribution network feeder automation terminal according to claim 1, characterized in that, An additional terminal is deployed at the midpoint of the line, including: The line whose length exceeds the longest reliable distance is selected as the analysis line, and the starting position P of the analysis line is obtained. H and end position P E ; Obtain all lines and key nodes in the distribution network, and determine the location of each key node relative to its starting point P. H The distance between them is used to set the first weight of each key node according to the rule that the smaller the distance, the larger the first weight, and the sum of the first weights is 1. Obtain the position P of the first end H Target value: Q represents the number of critical nodes in the distribution network, and W represents the number of critical nodes in the distribution network. q Let G be the first weight of the q-th key node. q The number of line segments connected to the q-th critical node; Analogy to the first position P H The target value is calculated using the method to obtain the end position P. E The target value; when adding terminals in the middle of the analysis line, the deployment should follow the rule that the closer to the end with the larger target value, the shorter the distance between two adjacent terminals, and the distance between any two adjacent terminals is less than the farthest reliable distance.

4. The method for traveling wave ranging of a distribution network feeder automation terminal according to claim 1, characterized in that, Determine the target section where the fault is located, including: Obtain the deployment location of all terminals in the distribution network, take the line segment between two adjacent terminals as a sub-segment, and traverse to obtain all sub-segments in the distribution network; Obtain the start position P1, end position P2, and length S of sub-segment K. K When a fault occurs in the distribution network, the traveling wave data captured by a terminal A deployed at the beginning position P1 and a terminal B deployed at the end position P2 are extracted respectively. The traveling wave data is analyzed to obtain the time difference Δt_AB between the fault traveling wave and the two terminals. Obtain the distance S between terminal A and the starting position P1. A1 And the distance S between terminal B and end position P2 B2 According to the traveling wave velocity V, if the following condition is met: Δt_AB is... and If the sub-segment K is between the two terminals, then the sub-segment K is taken as the segment to be determined; extract the traveling wave data captured by any sub-segment and any two terminals, and perform traversal calculation. If only the sub-segment K is determined as the segment to be determined in each traversal, then the sub-segment K is determined as the target segment.

5. The method for traveling wave ranging of a distribution network feeder automation terminal according to claim 4, characterized in that, Analyzing the traveling wave data, the time difference Δt_AB between the arrival times of the fault traveling wave at the two terminals is obtained, including: A fault traveling wave is a traveling wave signal whose traveling wave band exceeds the preset band threshold. Set a traveling wave acquisition time window, and extract the fault traveling wave function within the time window from the traveling wave data corresponding to terminal A and terminal B respectively. The fault traveling wave function is a function of the amplitude of the traveling wave band changing with time. Calculate the similarity between the two fault traveling wave functions. If the similarity is greater than a preset similarity threshold, it is determined that the traveling waves captured by terminal A and terminal B are valid traveling waves caused by the same fault. Obtain the time T when terminal A starts receiving the fault band. A The time T when terminal B begins receiving the faulty band. B The time difference Δt_AB is obtained.

6. The method for traveling wave ranging of a distribution network feeder automation terminal according to claim 1, characterized in that, The location of the fault point is obtained, including: Obtain the terminal M at the beginning of the target segment, the terminal N at the end of the target segment, and the segment length S. Based on the traveling wave data captured by terminals M and N, obtain the time difference Δt_MN between the arrival times of the fault traveling wave at the two terminals. Based on the traveling wave velocity V, use the formula: Calculate the fault distance X; the fault point is located on the target section at a distance X from the beginning and SX from the end.

7. A traveling wave ranging system for automated distribution network feeder terminals, used to execute the traveling wave ranging method for automated distribution network feeder terminals as described in any one of claims 1-6, characterized in that, The system includes a terminal deployment module, a target segment determination module, and a fault location module; Terminal deployment module: used to perform pulse signal testing on feeder automation terminals deployed in the distribution network, obtain the farthest reliable distance of terminal ranging, obtain the distribution network line topology, and obtain the key nodes in the distribution network according to the line connection relationship. Based on the farthest reliable distance and key nodes, the feeder automation terminals can be installed on the distribution network lines. Target section determination module: used to divide the distribution network into several sub-sections according to the terminal location; when a fault occurs in the distribution network, all terminals collect traveling wave data during the fault time according to a preset sampling time interval, and determine the target section where the fault point is located based on the traveling wave data of each terminal; Fault location module: used to obtain the terminal location and section length corresponding to the target section, and obtain the location of the fault point based on the traveling wave data of the terminal; output the obtained geographical coordinate information of the fault point to complete the fault location of the distribution network.

Images