Power distribution network line fault positioning method and system, terminal and storage medium

Abstract

The invention discloses a power distribution network line fault positioning method and system, a terminal and a storage medium, and belongs to the technical field of power distribution networks, and the method comprises the steps: judging whether a first fault occurs in a power distribution network line according to a first electric signal at one side of the power distribution network line, and determining corresponding first traveling wave head information if the first fault occurs; receiving second traveling wave head information sent by the second terminal; if the first fault and the second fault are the same fault, according to the first traveling wave head information and the second traveling wave head information, judging whether the fault position of the fault is in a power distribution network line section; if yes, determining the fault position of the fault according to the first traveling wave head information, the second traveling wave head information, the traveling wave propagation speed and the line length of the power distribution network cable section; according to the invention, the fault position of the power distribution network line can be accurately positioned through interactive communication between the local terminals without depending on a master station.

Description

Technical Field

[0001] This application relates to the field of power distribution network technology, specifically to a method, system, terminal, and storage medium for locating faults in power distribution network lines. Background Technology

[0002] With the growth of electricity demand, distribution networks are becoming increasingly complex, and the frequency of faults in these networks is also increasing. Urban distribution networks often have multiple T-connections, forming a radial distribution network. The numerous branches in urban distribution networks lead to complex traveling wave reflection paths, making it difficult to capture traveling waves. Traditional single-end traveling wave ranging methods are insufficient to meet the needs for rapid and accurate fault location in existing distribution networks.

[0003] Existing technologies have proposed a two-end traveling wave ranging method, which calculates the fault location by installing traveling wave detection equipment at both ends of the distribution network line and detecting the time difference of the arrival of the first traveling wave at both ends. However, the two-end traveling wave ranging method requires the traveling wave detection equipment at both ends to send the collected traveling wave information to the same master station system. Then, the traveling wave ranging system of the master station system performs comprehensive analysis based on the traveling wave information sent from each side to locate the fault point. This method is relatively dependent on the master station system. Summary of the Invention

[0004] In view of the above problems, this application provides a method, system, terminal and storage medium for locating faults in power distribution lines, aiming to solve the above technical problems.

[0005] In a first aspect, a method for locating faults in a power distribution network line is provided, applied to a first terminal installed on one side of the power distribution network line, wherein a second terminal is installed on the other side of the power distribution network line, the method comprising: The first electrical signal on one side of the power distribution line determines whether a first fault has occurred in the power distribution line. If a first fault has occurred, the corresponding first traveling wave front information is determined based on the first moment of the first fault and the second electrical signal on one side of the power distribution line. The second traveling wave header information sent by the second terminal is received, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after the second terminal judges that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line; If the first fault and the second fault are the same fault, then it is determined whether the fault is within the distribution network line segment based on the first traveling wavefront information and the second traveling wavefront information, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal; If the fault is located within the distribution network line segment, the fault location is determined based on the first traveling wave front information, the second traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment.

[0006] Optionally, the first electrical signal includes: a first three-phase voltage and a first three-phase current; the step of determining whether a first fault has occurred in the distribution network line based on the first electrical signal on one side of the distribution network line includes: If the first three-phase current experiences a continuous current change, then it is determined that the distribution network line has experienced a first fault, and the first moment corresponding to the first fault is determined. If the first three-phase current does not experience continuous current changes, but the first three-phase voltage experiences continuous voltage changes, then it is determined that the distribution network line has experienced a first fault, and the first moment corresponding to the first fault is determined.

[0007] Optionally, the second electrical signal includes: a first three-phase traveling wave current; the first traveling wave front information includes a first traveling wave front time stamp; determining the corresponding first traveling wave front information based on the first moment of the first fault and the second electrical signal on one side of the distribution network line includes: The first three-phase traveling wave current on one side of the distribution network line is sampled to obtain the corresponding first three-phase traveling wave current dataset. The first three-phase traveling wave current dataset includes the current value of the first three-phase traveling wave current within a first preset time period and the corresponding sampling time scale. The first target sampling time scale corresponding to the first three-phase traveling wave current data set is determined based on the first time point; The first three-phase traveling wave current data subset is determined in the first three-phase traveling wave current dataset according to the first target sampling time mark. The first three-phase traveling wave current data subset is the current value of the first three-phase traveling wave current in the first three-phase traveling wave current dataset within the second preset time mark from the first target sampling time mark to the previous second preset time mark and the corresponding sampling time mark. The second preset time mark is less than or equal to the first preset time mark. The sampling time stamp corresponding to the maximum current value in the first three-phase traveling wave current data subset is determined as the first traveling wave wavefront time stamp.

[0008] Optionally, the step of saying that the first fault and the second fault are the same fault includes: If the second traveling wave header information sent by the second terminal is received within the third preset time period after the first moment, then the first fault and the second fault are determined to be the same fault.

[0009] Optionally, the second traveling wavefront information includes a second traveling wavefront time stamp; the step of determining whether the fault is within the distribution network segment based on the first traveling wavefront information and the second traveling wavefront information includes: The first traveling wave distance measurement result of the first terminal is determined based on the first traveling wave wavefront timescale, the second traveling wave wavefront timescale, the traveling wave propagation speed, and the line length of the distribution network line segment; If the first traveling wave ranging result is less than the line length, then the fault is determined to be within the distribution network line segment.

[0010] Optionally, the method further includes: sending the first traveling wave wavefront time stamp to the second terminal, so that the second terminal determines the second traveling wave ranging result of the fault distance to the second terminal based on the second traveling wave wavefront time stamp, the first traveling wave wavefront time stamp, the traveling wave propagation speed and the line length; The step of determining the fault location based on the first traveling wavefront information, the second traveling wavefront information, the traveling wave propagation speed, and the line length of the distribution network segment includes: Receive the second traveling wave ranging result sent by the second terminal; The corresponding ranging compensation value is determined based on the first traveling wave ranging result, the second traveling wave ranging result, and the line length. The fault location is determined based on the first traveling wave ranging result and the ranging compensation value.

[0011] Secondly, a method for locating faults in a power distribution network line is also provided, applied to a second terminal installed on the other side of the power distribution network line, wherein a first terminal is installed on one side of the power distribution network line, and the method includes: The second fault is determined based on the third electrical signal on the other side of the power distribution line. If the second fault occurs, the corresponding second traveling wavefront information is determined based on the fourth electrical signal on the other side of the power distribution line and the second time of the second fault. The system receives first traveling wave header information sent by the first terminal, wherein the first traveling wave header information is determined by the first terminal based on the first electrical signal on one side of the power distribution line to determine that a first fault has occurred in the power distribution line, and based on the first moment of the first fault and the second electrical signal on one side of the power distribution line. If the first fault and the second fault are the same fault, then it is determined whether the fault is within the distribution network line segment based on the second traveling wavefront information and the first traveling wavefront information, wherein the distribution network line segment is the distribution network line between the second terminal and the first terminal; If the fault is located within the distribution network line segment, the fault location is determined based on the second traveling wavefront information, the first traveling wavefront information, the traveling wave propagation speed, and the line length of the distribution network line segment.

[0012] Thirdly, a fault location system for a power distribution network line is also provided, which is applied to a first terminal installed on one side of the power distribution network line, and a second terminal installed on the other side of the power distribution network line, comprising: The wavefront determination module is used to determine whether a first fault has occurred in the distribution network line based on a first electrical signal on one side of the distribution network line. If a first fault has occurred, the corresponding first traveling wavefront information is determined based on the first moment of the first fault and a second electrical signal on one side of the distribution network line. The information receiving module is used to receive the second traveling wave header information sent by the second terminal, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after judging that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line; The fault determination module is used to determine whether the fault is within the distribution network line segment based on the first traveling wave wavefront information and the second traveling wave wavefront information if the first fault and the second fault are the same fault, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal; The fault location module is used to determine the fault location based on the first traveling wave wavefront information, the second traveling wave wavefront information, the traveling wave propagation speed, and the line length of the distribution network line segment if the fault is located within the distribution network line segment.

[0013] Fourthly, a terminal is also provided, including a sampling component, a memory, and a processor. The sampling component is used to measure the voltage, current, and traveling wave current of the distribution network line. The memory stores a computer program, which, when executed by the processor, implements the above-mentioned method for locating faults in the distribution network line.

[0014] Fifthly, a computer-readable storage medium is also provided, on which a computer program is stored, which is loaded by a processor to perform the steps in the above-described method for locating faults in power distribution lines.

[0015] In this application, a first fault is determined based on a first electrical signal on one side of the distribution network line. If a first fault occurs, the corresponding first traveling wave front information is determined based on the first moment of the first fault and the second electrical signal on one side of the distribution network line. Second traveling wave front information sent by the second terminal is received. This second traveling wave front information is determined by the second terminal based on a second moment of the second fault and a fourth electrical signal on the other side of the distribution network line after determining a second fault based on a third electrical signal on the other side of the distribution network line. If the first fault and the second fault are the same fault, the fault is determined based on the first and second traveling wave front information to determine whether it is within a distribution network line segment, where the distribution network line segment is the distribution network line between the first terminal and the second terminal. If the fault is within the distribution network line segment, the fault location is determined based on the first and second traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment. This achieves accurate determination of the fault location of a distribution network line fault without relying on a master station, through interactive communication between local terminals. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a method for locating faults in power distribution lines provided in some embodiments of this application; Figure 2 This is another schematic flowchart of the method for locating faults in power distribution lines provided in some embodiments of this application; Figure 3 This is yet another flowchart illustrating the method for locating faults in power distribution lines provided in some embodiments of this application; Figure 4 These are schematic diagrams illustrating application embodiments of the power distribution line fault location method provided in some embodiments of this application; Figure 5 This is a schematic diagram of another application embodiment of the fault location method for power distribution lines provided in some embodiments of this application; Figure 6 This is a structural block diagram of a power distribution line fault location system provided in some embodiments of this application; Figure 7 This is a schematic diagram of the structure of a terminal provided in some embodiments of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0021] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0022] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0023] Before introducing the method, system, terminal and storage medium for fault location of power distribution lines in this application, we will first introduce the relevant background information of the embodiments of this application.

[0024] The existing two-end traveling wave ranging method involves installing traveling wave detection equipment at both ends of the distribution network line and calculating the fault location by detecting the time difference between the arrival of the first traveling wave at both ends. However, the two-end traveling wave ranging method requires the traveling wave detection equipment at both ends to send the collected traveling wave information to the same master station system. Then, the traveling wave ranging system of the master station system performs comprehensive analysis based on the traveling wave information sent from each side to locate the fault point. This method is highly dependent on the master station system.

[0025] Based on this, this application provides a method for locating faults in a power distribution network. The hardware environment of this application includes installing a terminal on each side of the power distribution network line. A first terminal is installed on one side of the power distribution network line, and a second terminal is installed on the other side. Both the first and second terminals can collect voltage and current signals and traveling wave current signals from the power distribution network line and analyze whether a fault has occurred, thereby determining the first traveling wave front. Both the first and second terminals are configured with high-precision BeiDou time synchronization (GPS, etc., can also be used) to achieve time alignment between different terminals. Simultaneously, the first and second terminals can communicate wirelessly or wiredly, using standardized GOOSE peer-to-peer communication technology for information exchange. GOOSE communication offers high real-time performance, speed, efficiency, and reliability. Both the first and second terminals can be installed at any location on the power distribution network line for measurement. In practical applications, both the first and second terminals can be installed at the power distribution network switch. The first and second terminals acquire the corresponding power frequency three-phase voltage and power frequency three-phase current, and also acquire the corresponding high-frequency traveling wave current. The first and second terminals are time-synchronized based on GPS / BeiDou, achieving a time synchronization accuracy of hundreds of nanoseconds.

[0026] In a first aspect, embodiments of this application provide a method for locating faults in a power distribution network line, applied to a first terminal installed on one side of the power distribution network line, wherein a second terminal is installed on the other side of the power distribution network line, such as... Figure 1 As shown, the method includes the following steps S110 to S140, which are explained in detail below.

[0027] Step S110: Determine whether a first fault has occurred in the distribution network line based on the first electrical signal on one side of the distribution network line. If a first fault has occurred, determine the corresponding first traveling wavefront information based on the first moment of the first fault and the second electrical signal on one side of the distribution network line.

[0028] In this embodiment, the first terminal can be a distribution network terminal. The first terminal determines whether a first fault has occurred in the distribution network line based on a first electrical signal on one side of the distribution network line. If a first fault occurs, the first traveling wave front information corresponding to the first fault is determined based on the first time corresponding to the first fault (which can be the current time when the first terminal confirms the occurrence of the first fault) and the second electrical signal on one side of the distribution network line. In the prior art, the first traveling wave front information is generally the first traveling wave front after a fault occurs in the distribution network.

[0029] In practical applications, the first electrical signal (such as voltage signal or current signal) of the distribution network line is collected by the first terminal installed on one side of the distribution network line to determine whether a fault has occurred. If a fault occurs, the first traveling wave front is found from the second electrical signal (such as traveling wave current signal) collected by the first terminal on one side of the distribution network line, and the corresponding first traveling wave front information is determined based on the first traveling wave front found.

[0030] In this embodiment, step S110 may include sub-steps of steps S101 to S102, which will be described in detail below.

[0031] The first electrical signal includes: a first three-phase voltage and a first three-phase current. Step S11, determining whether a first fault has occurred in the distribution network line based on the first electrical signal on one side of the distribution network line, includes: Step S101: If the first three-phase current undergoes continuous current change, it is determined that the distribution network line has a first fault, and the first moment corresponding to the first fault is determined. Step S102: If the first three-phase current does not experience continuous current change, but the first three-phase voltage experiences continuous voltage change, then it is determined that the distribution network line has experienced a first fault, and the first moment corresponding to the first fault is determined.

[0032] In this embodiment, the first terminal samples the first three-phase voltage and the first three-phase current on one side of the distribution network line. Specifically, the first terminal samples the first three-phase voltage on one side of the distribution network line to obtain the corresponding voltage value, records the corresponding sampling timestamp, and stores it accordingly; the first terminal samples the first three-phase current on one side of the distribution network line to obtain the corresponding current value, records the corresponding sampling timestamp, and stores it accordingly. The first terminal can determine whether a fault has occurred in the distribution network based on sudden changes in voltage and current on the distribution network line. To improve the accuracy of fault detection and avoid false triggering by power grid fluctuations, this embodiment uses a continuous change mechanism to determine whether a fault has occurred in the distribution network.

[0033] The first terminal can determine whether a first fault has occurred in the distribution network line based on a first electrical signal on one side of the distribution network line. This can be determined by whether there are continuous abrupt changes in the three-phase current signal and / or three-phase voltage signal. Specifically, if the first three-phase current experiences continuous current abrupt changes, the distribution network line is determined to have experienced a first fault, and the first moment corresponding to the first fault is determined. If the first three-phase current does not experience continuous current abrupt changes, the terminal determines whether the first three-phase voltage experiences continuous voltage abrupt changes. If the first three-phase voltage experiences continuous voltage abrupt changes, the distribution network line is determined to have experienced a first fault, and the first moment corresponding to the first fault is determined. In practical applications, the frequencies corresponding to the first three-phase voltage and first three-phase current are generally the power frequency (the power frequency may vary in different national power grids, commonly 50Hz or 60Hz).

[0034] In practical applications, the power frequency acquisition module of the first terminal collects three-phase voltage and three-phase current at the power frequency, with a sampling rate of 1KHz / s-4KHz / s and a power frequency of 50Hz. Based on GPS / BeiDou time stamps, the first terminal assigns a corresponding sampling time stamp to each power frequency sampled data. The first terminal can use circular storage (e.g., a first-in-first-out memory) to store the power frequency sampled data; for example, it can use a cache to store sampled data and corresponding sampling time stamps for a certain period of time.

[0035] In this embodiment, the first terminal determines the fault time and fault phase based on the transient change in power frequency voltage / current. Regarding the transient change in power frequency voltage or current, this embodiment can compare three consecutive sampling points with the sampling points corresponding to the previous two cycles. If the difference between the three consecutive sampling points and the sampling points in the three consecutive cycles exceeds a preset threshold, then a fault is determined to have occurred; compared with the prior art, the fault determination is more accurate.

[0036] To further improve the accuracy of fault diagnosis, this embodiment can first determine whether the first three-phase current has undergone continuous abrupt changes. If continuous current abrupt changes occur, the first fault is determined to have occurred, and the first moment corresponding to the first fault is determined. If no continuous current abrupt changes occur, the first three-phase voltage is then determined to have undergone continuous voltage abrupt changes. If continuous voltage abrupt changes occur, the first fault is determined to have occurred, and the first moment corresponding to the first fault is determined. This makes the fault diagnosis more accurate.

[0037] In practical applications, the transient zero-sequence current mutation value ΔI(k) is based on the power frequency sampling value. The mutation value is calculated as ΔI(k) = |(I(k)-I(kn))-(I(kn) - I(k-2n))|. If ΔI(k) > Iset, and the sampling points corresponding to the first three phase currents of three consecutive cycles all satisfy the condition, then a fault is considered to have started, and the phase that satisfies the condition is the faulty phase. Here, k is the current sampling point, n is the number of sampling points per cycle, Iset is the preset current mutation threshold, which is the current mutation start threshold; I(k)-I(kn) is the difference between the current value of the current sampling point and the current value of the same sampling point in the previous cycle; (I(kn) - I(k-2n) is the difference between the current value of the same sampling point in the previous cycle and the current value of the same sampling point in the cycle before that. If the difference between these two values ​​ΔI(k) is greater than the preset current mutation threshold, and three consecutive sampling points, such as k-1, k, and k+1, all satisfy the above current mutation formula, then a fault is considered to have occurred.

[0038] When the current surge does not meet the start-up condition, the voltage surge is used to determine the fault start-up. ΔU(k)=|(U(k)-U(kn)) - (U(kn) - U(k-2n))|. When ΔU(k)>Uset, and the sampling points corresponding to the first three phase voltages meet the condition for three consecutive times, the fault start-up is determined, and the phase that meets the condition is the fault phase. The fault start-up time stamp and the fault phase are recorded. Here, k is the current sampling point, n is the number of sampling points per cycle, and Uset is the preset voltage surge threshold, which is the voltage surge start-up threshold. U(k)-U(kn) is the difference between the voltage value of the current sampling point and the voltage value of the same sampling point in the previous cycle; U(kn)-U(k-2n) is the difference between the voltage value of the same sampling point in the previous cycle and the voltage value of the same sampling point in the cycle before that; if the difference between these two values ​​ΔU(k) ​​is greater than the preset voltage change threshold Uset, and three consecutive sampling points, such as k-1, k, and k+1, satisfy the above voltage change formula, then a fault is considered to have occurred. The fault start time (i.e., the fault time corresponding to the fault) and the fault phase are recorded. Compared with the existing technology, the fault judgment is more accurate.

[0039] In this embodiment, step S110 may also include sub-steps S111 to S114, which will be described in detail below.

[0040] The second electrical signal includes: a first three-phase traveling wave current; the first traveling wave front information includes a first traveling wave front time stamp; determining the corresponding first traveling wave front information based on the first moment of the first fault and the second electrical signal on one side of the distribution network line includes: Step S111: Sample the first three-phase traveling wave current on one side of the distribution network line to obtain the corresponding first three-phase traveling wave current dataset. The first three-phase traveling wave current dataset includes the current value of the first three-phase traveling wave current within a first preset time period and the corresponding sampling time scale. Step S112: Determine the first target sampling time scale in the first three-phase traveling wave current data set based on the first time point; Step S113: Determine the first three-phase traveling wave current data subset corresponding to the first three-phase traveling wave current dataset according to the first target sampling time mark, wherein the first three-phase traveling wave current data subset is the current value of the first three-phase traveling wave current within the first target sampling time mark to the second preset time mark in the first three-phase traveling wave current dataset and the corresponding sampling time mark, and the second preset time mark is less than or equal to the first preset time mark; Step S114: Determine the sampling time stamp corresponding to the maximum current value in the first three-phase traveling wave current data subset as the first traveling wave wavefront time stamp.

[0041] In this embodiment, the first terminal collects the first three-phase traveling wave current on one side of the distribution network line. The three-phase traveling wave current has high-frequency characteristics. Specifically, the first terminal samples the three-phase traveling wave current signal on one side of the distribution network line to obtain the corresponding current value, records the corresponding sampling timestamp, and stores them accordingly. In this embodiment, the stored first three-phase traveling wave current value and corresponding sampling timestamp for a first preset duration are used as the first three-phase traveling wave current dataset.

[0042] In existing technologies, traveling wave current information of distribution network lines is typically collected and uploaded to the master station. The master station then uses this traveling wave current information to diagnose faults. However, since the traveling wave current information is collected at high frequency, the amount of data stored by the master station is relatively large, resulting in high hardware costs and slow processing efficiency.

[0043] This embodiment eliminates the need to upload to a main station. Instead, a first terminal stores the sampling data of the first three-phase traveling wave current for a first preset duration. The high-speed acquisition module of the first terminal has a sampling rate greater than 3 MHz / s. The high-frequency sampling data can be stored cyclically (e.g., using a first-in-first-out memory, FIFO buffer), meaning it uses a buffer to store the sampling data and its corresponding sampling timestamp within the first preset duration. Considering both hardware cost and fault analysis accuracy, the first preset duration can be 100 ms. The first three-phase traveling wave current dataset can be 100 ms of high-frequency sampling data, including the traveling wave current value and its corresponding sampling timestamp, where the sampling timestamp is the sampling time corresponding to the data collected at the sampling point. This avoids the large amount of working data and high hardware cost associated with directly using high-frequency traveling wave current for identification.

[0044] In this embodiment, after the first terminal determines the fault time marker (i.e., the first moment) and the fault phase through the power frequency component, it can determine the first target sampling time marker corresponding to the first three-phase traveling wave current data based on the first moment.

[0045] From the first three-phase traveling wave current dataset (i.e., the high-frequency traveling wave current data cached in the first terminal) with a first preset duration, the sampled data of the first three-phase traveling wave current from the first target sampling time marker to the second preset duration prior is determined, including the current value and sampling time marker during this time period, i.e., a subset of the first three-phase traveling wave current data. It can be understood that the second preset duration is less than or equal to the first preset duration.

[0046] Find the maximum current value from the sampled data of the traveling wave current during the time period from the first target sampling time mark to the second preset time period before it. Take the three-phase traveling wave current corresponding to the maximum traveling wave current value in this time period as the first traveling wave front, and take the sampling time mark corresponding to the maximum traveling wave current value in this time period as the first traveling wave front time mark.

[0047] In practical applications, the second preset duration can be 20ms. After the first terminal determines the fault time marker and fault phase through the power frequency component, it retrieves the cached 100ms three-phase traveling wave current sampling data from the first moment of the first fault, looking up the cached traveling wave current sampling data for the period from the first moment to 20ms prior. The three-phase traveling wave current corresponding to the maximum value of the traveling wave current value in this period is taken as the first traveling wave head (i.e., the first traveling wave head), and the corresponding sampling time marker is taken as the first traveling wave head time marker. The first traveling wave head time marker is the sampling time marker corresponding to the first traveling wave head, accurate to the nanosecond level. To reduce the amount of communication data and improve efficiency, the first traveling wave head information can be the first traveling wave head time marker.

[0048] Step S120: Receive the second traveling wave header information sent by the second terminal, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after judging that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line.

[0049] In this embodiment, the first terminal receives second traveling wavefront information sent by a second terminal installed on the other side of the power distribution network line via GOOSE peer-to-peer communication technology. The process for determining the second traveling wavefront information is the same as that for determining the first traveling wavefront information; that is, the second terminal uses the same working principle as the first terminal to determine the second traveling wavefront information. The second terminal determines whether a second fault has occurred in the power distribution network line based on a third electrical signal on the other side of the power distribution network line. If a second fault has occurred, the second terminal determines the corresponding second traveling wavefront information based on the second time of the second fault and a fourth electrical signal on the other side of the power distribution network line. In practical applications, the first and second terminals have identical hardware, and both terminals are based on GPS / BeiDou timescales.

[0050] Step S130: If the first fault and the second fault are the same fault, then determine whether the fault is within the distribution network line segment based on the first traveling wavefront information and the second traveling wavefront information, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal.

[0051] In this embodiment, the first terminal confirms whether the first fault and the second fault are the same fault. That is, both the first terminal and the second terminal on the distribution network line sense a fault in the distribution network line. The principle of the second terminal's fault judgment is the same as that of the first terminal, and will not be repeated here. The first moment is the moment when the first terminal judges that a fault has occurred, and the second moment is the moment when the second terminal judges that a fault has occurred. Since the propagation speed of electrical signals is very fast, based on the existing deployment distance between the first terminal and the second terminal on the distribution network line, the time difference between the first terminal and the second terminal sensing the same fault is very small, possibly on the order of milliseconds.

[0052] In practical applications, the time difference between the first terminal and the second terminal sensing the same fault is generally within 1 millisecond. This embodiment can determine whether the faults sensed by the first terminal and the second terminal are the same fault based on this time difference. Specifically, if the first fault and the second fault are the same fault, it includes: if the second traveling wavefront information sent by the second terminal is received within a third preset time period after the first moment, then it is determined that the first fault and the second fault are the same fault.

[0053] In this embodiment, a third preset duration (e.g., 1ms) is set on the first terminal. The first terminal records the first moment when the first fault is detected. If the first terminal receives the second traveling wave header information sent by the second terminal within the time period from the first moment to the third preset duration, it is considered to be the same fault.

[0054] It is understandable that the first terminal can also determine whether the first fault and the second fault are the same fault based on whether the time difference between the first traveling wave header information and the second traveling wave header information is less than a preset time difference threshold (e.g., 1ms). If the time difference between the first traveling wave header information and the second traveling wave header information is less than the preset time difference threshold (which can also be adjusted according to the actual situation), then it is considered whether the first fault and the second fault are the same fault. Otherwise, they are not the same fault.

[0055] In this embodiment, step S130 may include sub-steps of steps S131 and S132, which are described in detail below. The second traveling wavefront information includes a second traveling wavefront time stamp. The step of determining whether the fault is within the distribution network line segment based on the first traveling wavefront information and the second traveling wavefront information includes: Step S131: Determine the first traveling wave distance measurement result of the first terminal based on the first traveling wave wavefront timescale, the second traveling wave wavefront timescale, the traveling wave propagation speed, and the line length of the distribution network line segment; Step S132: If the first traveling wave ranging result is less than the line length, then the fault is determined to be within the distribution network line segment.

[0056] In this embodiment, the first terminal receives second traveling wavefront information sent by the second terminal. The second traveling wavefront information includes a second traveling wavefront time stamp. The process for determining the second traveling wavefront time stamp is the same as the principle by which the first terminal determines the first traveling wavefront time stamp, and will not be repeated here. Based on the first and second traveling wavefront information, the first terminal can determine whether the fault is within the distribution network segment.

[0057] Specifically, based on the first terminal on one side of the distribution network line, the distance between the fault and the first terminal can be calculated using a ranging formula. The ranging formula is: S1=1 / 2*[L+v*(T1-T2)]; where T1 is the time scale of the first traveling wave front, T2 is the time scale of the second traveling wave front, v is the traveling wave propagation speed, L is the length of the distribution network line, and S1 is the ranging result of the first traveling wave.

[0058] If the first traveling wave ranging result S1 is zero or equal to the line length L of the distribution network, then the fault is not within that distribution network line segment. If the first traveling wave ranging result is less than the line length L of the distribution network line segment, then the fault is within that distribution network line segment, which is the distribution network line between the first terminal and the second terminal. Generally, the first traveling wave ranging result cannot exceed the line length L.

[0059] In some embodiments, the first terminal may also send the first traveling wave header information to the second terminal, and the first traveling wave header time stamp may be sent to the second terminal on the other side via a GOOSE message, so that the second terminal can also implement the same fault location method steps as the first terminal.

[0060] Step S140: If the fault is within the distribution network line segment, the fault location is determined based on the first traveling wave front information, the second traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment.

[0061] In this embodiment, if the fault is located within the distribution network line segment, the fault location can be determined based on the first traveling wave front information, the second traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment. Addressing the issue of existing dual-end ranging methods requiring the collection of traveling wave information to be uploaded to a single master station for analysis, thus creating reliance on the master station, this embodiment eliminates the need for uploading to a master station. The fault location in the distribution network line can be determined using communication between the first terminal and the second terminal, with a very small amount of communication data.

[0062] In this embodiment, the first terminal also sends the first traveling wave wavefront time stamp to the second terminal, so that the second terminal can determine the second traveling wave ranging result of the fault distance to the second terminal based on the second traveling wave wavefront time stamp, the first traveling wave wavefront time stamp, the traveling wave propagation speed and the line length.

[0063] In this embodiment, step S140 may include sub-steps of steps S141 to S143, which will be described in detail below.

[0064] The step of determining the fault location based on the first traveling wavefront information, the second traveling wavefront information, the traveling wave propagation speed, and the line length of the distribution network segment includes: Step S141: Receive the second traveling wave ranging result sent by the second terminal; Step S142: Determine the corresponding ranging compensation value based on the first traveling wave ranging result, the second traveling wave ranging result, and the line length; Step S143: Determine the fault location based on the first traveling wave ranging result and the ranging compensation value.

[0065] In this embodiment, in order to further improve the fault location accuracy, the first terminal not only calculates the first traveling wave ranging result S1 of the fault distance to the first terminal, but also receives the second traveling wave ranging result S2 of the fault distance to the second terminal sent by the second terminal. Regarding how the second terminal determines the second traveling wave ranging result, the method of the first terminal determining the first traveling wave ranging result can be referred to. The two are based on the same principle and will not be described again here.

[0066] The first terminal determines the corresponding ranging compensation value △L based on the first traveling wave ranging result S1, the second traveling wave ranging result S2, and the line length L; where △L=(S1+S2-L) / 2.

[0067] The first terminal compensates the first traveling wave ranging result based on the ranging compensation value, and determines the fault location S as: S = S1 - ΔL. Thus, through compensation, the distance between the fault location and the first terminal is finally determined, thereby enabling more accurate fault location.

[0068] This application uses power frequency voltage or current signals to trigger fault identification, thereby determining the first traveling wave front of the fault. This avoids the large amount of data required for identification using high-frequency traveling wave current. This application relies on power frequency sampling to initiate fault judgment, determining the fault time through sampling. This allows for more accurate fault timing and prevents the frequent activation of traveling wave components caused by existing methods using high-frequency traveling wave current, significantly reducing computational requirements. This application uses a first terminal installed on one side of the distribution network line and a second terminal installed on the other side. Based on wired or wireless peer-to-peer communication using the GOOSE protocol, they only exchange the determined wave front information. Normally, they exchange heartbeat messages, resulting in low data consumption, making it both reliable and economical. This application can accurately determine the fault location of the distribution network line through communication between local terminals, without relying on a master station.

[0069] Secondly, embodiments of this application provide a method for locating faults in power distribution network lines, such as... Figure 2 As shown, the method applies to a second terminal installed on the other side of a power distribution network line, wherein a first terminal is installed on one side of the power distribution network line, and includes the following steps: Step S210: Determine whether a second fault has occurred in the distribution network line based on the third electrical signal on the other side of the distribution network line. If a second fault has occurred, determine the corresponding second traveling wavefront information based on the fourth electrical signal on the other side of the distribution network line and the second time of the second fault. Step S220: Receive the first traveling wave header information sent by the first terminal, wherein the first traveling wave header information is determined by the first terminal based on the first electrical signal on one side of the distribution network line to determine that the distribution network line has a first fault, and based on the first moment of the first fault and the second electrical signal on one side of the distribution network line. Step S230: If the first fault and the second fault are the same fault, then determine whether the fault is within the distribution network line segment based on the second traveling wave front information and the first traveling wave front information, wherein the distribution network line segment is the distribution network line between the second terminal and the first terminal; Step S240: If the fault is within the distribution network line segment, the fault location is determined based on the second traveling wave front information, the first traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment.

[0070] The fault location method for distribution network lines provided in the second aspect is applied to a second terminal installed on the other side of the distribution network line, and its working principle is the same as that of the fault location method for distribution network lines provided in the first aspect applied to the first terminal. The specific process of the second terminal determining the second traveling wavefront information is as follows.

[0071] In some examples of this embodiment, the second terminal determines whether a second fault has occurred in the distribution network line based on a third electrical signal on the other side of the distribution network line. If a second fault occurs, the corresponding second traveling wavefront information is determined based on the second time of the second fault and a fourth electrical signal on the other side of the distribution network line.

[0072] In some examples of this embodiment, the third electrical signal includes: a second three-phase voltage and a second three-phase current; determining whether a second fault has occurred in the distribution network line based on the third electrical signal on the other side of the distribution network line includes: If the second and third phase currents experience continuous current abrupt changes, then it is determined that the distribution network line has experienced a second fault, and the second time corresponding to the second fault is determined. If the second and third phase currents do not experience continuous current abrupt changes, but the second and third phase voltages experience continuous voltage abrupt changes, then it is determined that the distribution network line has experienced a second fault, and the second time corresponding to the second fault is determined.

[0073] In some examples of this embodiment, the fourth electrical signal includes: a second three-phase traveling wave current; the second traveling wave front information includes a second traveling wave front time stamp; determining the corresponding second traveling wave front information based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line includes: The second terminal samples the second and third phase traveling wave currents on the other side of the distribution network line to obtain the corresponding second and third phase traveling wave current dataset. The second and third phase traveling wave current dataset includes the current values ​​of the second and third phase traveling wave currents within a first preset time period and the corresponding sampling timestamps. The second terminal determines the second target sampling time scale corresponding to the second three-phase traveling wave current data set based on the second time. The second terminal determines the corresponding subset of the second three-phase traveling wave current data in the second three-phase traveling wave current dataset according to the second target sampling time stamp. The subset of the second three-phase traveling wave current data consists of the current value of the second three-phase traveling wave current within the second target sampling time stamp to the second preset time period in the second three-phase traveling wave current dataset and the corresponding sampling time stamp. The second preset time period is less than or equal to the first preset time period. The second terminal determines the sampling time stamp corresponding to the maximum current value in the second three-phase traveling wave current data subset as the second traveling wave wavefront time stamp.

[0074] In some embodiments, the second terminal determines whether a second fault has occurred in the distribution network line based on a third electrical signal on the other side of the distribution network line. If a second fault occurs, the second terminal determines the corresponding second traveling wavefront information based on the fourth electrical signal and the second time. The third electrical signal includes: second three-phase voltage and second three-phase current; the fourth electrical signal includes the second three-phase traveling wave current.

[0075] The principle of fault judgment by the second terminal is the same as that of the first terminal, and will not be repeated here. The first moment is the moment when the first terminal judges the fault to have occurred, and the second moment is the moment when the second terminal judges the fault to have occurred. Due to the high speed of electrical signal propagation, and based on the existing distance between the first and second terminals on the distribution network lines, the time difference between the first and second terminals sensing the same fault is very small, possibly on the order of milliseconds. Generally, the time difference between the first and second moments is within 1 millisecond. This embodiment can determine whether the faults identified by the first and second terminals are the same fault based on this time difference.

[0076] It should be noted that, in order to facilitate mass production and configuration, the first preset duration and the second preset duration in the process of determining the second traveling wave head information in the second terminal are preferably the same as the first preset duration and the second preset duration in the process of determining the first traveling wave head information in the first terminal. Of course, different first preset durations and second preset durations can also be set for different terminals according to the actual situation.

[0077] The second terminal confirms the second traveling wave head information corresponding to the occurrence of the second fault. The second traveling wave head information includes the corresponding second traveling wave head time stamp. The second traveling wave head time stamp is sent to the first terminal, and the second traveling wave ranging result is also sent to the first terminal, so that the first terminal can perform the steps of the first aspect of the power distribution line fault location method.

[0078] The second terminal also receives the first traveling wave wavefront time stamp and the first traveling wave ranging result sent by the first terminal, in order to perform the steps of the second aspect of the power distribution line fault location method.

[0079] In practical applications, the fault location method for power distribution lines provided in this application collects the three-phase voltage and three-phase current at power frequency and the three-phase traveling wave current at high frequency by installing a first terminal and a second terminal on both sides of the power distribution line. Both terminals are based on GPS / BeiDou time synchronization, and the high-frequency sampling is cyclically buffered for 100ms of data, with each sampling point marked with a time stamp. The terminals at both ends determine the fault time and fault phase based on the transient change in power frequency voltage / current. From the high-frequency buffered traveling wave current, based on the fault time determined by the power frequency transient, the high-frequency sampling current is searched back 20ms, and the maximum value of the sampling is taken as the traveling wave head, and the traveling wave head time stamp is recorded.

[0080] The first terminal sends the first traveling wavefront time stamp to the second terminal via a GOOSE message and receives the second traveling wavefront time stamp from the second terminal. The first terminal, by combining the second wavefront time stamp received from the second terminal with its own first wavefront time stamp, performs a comprehensive analysis and comparison to determine whether the fault occurs within or outside the distribution network segment. The terminals on both sides exchange traveling wave ranging results (i.e., the first and second traveling wave ranging results) via GOOSE communication. Both the first and second terminals can perform ranging compensation, thereby accurately locating the fault.

[0081] This application adopts the method of local terminals exchanging wavefront information. By comparing and analyzing the wavefront information between them, the fault section is determined. By analyzing the results of the segment through mutual interaction, the fault location can be determined relatively accurately. The fault location can be quickly determined locally between terminals without relying on the main station analysis system.

[0082] In some embodiments, this application also provides a method for locating faults in distribution network lines, such as... Figure 3 As shown, the method is applied to any terminal installed on a power distribution network line, wherein multiple terminals are installed on the power distribution network line, and the multiple terminals divide the power distribution network line into multiple power distribution network line segments; the method includes: Step S310: The terminal collects the voltage and current signals of the corresponding distribution network line segment to determine whether a fault has occurred. If a fault has occurred, the terminal determines the corresponding traveling wave front timescale based on the collected traveling wave current signal of the corresponding distribution network line segment. Step S320: The terminal receives at least one adjacent traveling wave wavefront time stamp sent by at least one adjacent terminal, wherein the adjacent traveling wave wavefront time stamp is determined by the adjacent terminal based on the traveling wave current signal of the corresponding distribution network line segment after judging that a fault has occurred based on the voltage and current signals of the corresponding distribution network line segment collected. Step S330: The terminal determines whether the fault is within the corresponding distribution network line segment based on the traveling wave wavefront time stamp and at least one adjacent traveling wave wavefront time stamp; Step S340: If yes, the terminal determines the fault location based on the traveling wave wavefront timescale, the traveling wave wavefront timescale corresponding to the distribution network line segment where the fault is located, the traveling wave propagation speed, and the line length of the distribution network line segment where the fault is located.

[0083] Specifically, given the complexity of power distribution network lines, in practical applications, the hardware environment provided in this embodiment includes terminals installed at multiple measurement points along the power distribution network lines. Each terminal can collect voltage and current signals from corresponding power distribution network line segments to analyze whether a fault has occurred. In the event of a fault, the first traveling wave front is determined based on the traveling wave current signal of the corresponding power distribution network line segment as the corresponding traveling wave front time stamp. Each terminal is configured with high-precision BeiDou time synchronization (GPS, etc., can also be used) to achieve time alignment between different terminals. Simultaneously, adjacent terminals can communicate wirelessly or via wired connections, using standardized GOOSE peer-to-peer communication technology for information exchange. GOOSE communication offers high real-time performance, speed, efficiency, and reliability.

[0084] Each terminal can be installed at any location on the distribution network line for measurement. In practical applications, multiple terminals are installed at multiple distribution network switches on the distribution network line. Each terminal acquires the power frequency three-phase voltage and power frequency three-phase current of the corresponding distribution network line segment, and also acquires the high-frequency traveling wave current of the corresponding distribution network line segment. Each terminal uses GPS / BeiDou time synchronization, with a synchronization accuracy reaching the level of hundreds of nanoseconds. Each terminal interacts with at least one adjacent terminal using GOOSE peer-to-peer communication technology. Each terminal can interact with adjacent terminals to perform fault location, and its working principle can refer to the distribution network line fault location method provided in the first or second aspect.

[0085] In actual power distribution network lines, any terminal installed on the line may have one, two, or even three adjacent terminals (it should be noted that, from the perspective of power distribution network architecture, a terminal can have a maximum of three adjacent terminals). Any terminal can communicate with its adjacent terminals via GOOSE peer-to-peer communication, including traveling wavefront timing. Multiple terminals installed on an actual power distribution network line can divide the network into multiple corresponding segments. If a fault occurs, the fault location can be determined using a ranging formula within a specific segment. Its working principle is the same as the power distribution network fault location method provided in the first or second aspect.

[0086] If a terminal has only one adjacent terminal, the specific process steps of the distribution network line fault location method applied to that terminal can refer to the distribution network line fault location method in the first or second aspect.

[0087] If a terminal has two adjacent terminals, then the terminal will receive two adjacent traveling wave head time stamps sent by the two adjacent terminals. The terminal's traveling wave head time stamp is calculated with the two adjacent traveling wave head time stamps respectively to further determine the fault location.

[0088] Please continue reading. Figure 4 , Figure 4 This diagram illustrates an application embodiment of the power distribution line fault location method provided in some embodiments of this application. Each power distribution switch corresponds to one terminal: power distribution switch FS1 corresponds to terminal 1, power distribution switch FS2 corresponds to terminal 2, power distribution switch FS3 corresponds to terminal 3, and power distribution switch FS4 corresponds to terminal 4. Figure 4 As an example, it can be seen that terminal 1 of distribution network switch FS1 has only one adjacent terminal, which is terminal 2 corresponding to distribution network switch FS2. Terminal 2 corresponding to distribution network switch FS2 has three adjacent terminals, including terminal 1, terminal 3, and terminal 4. It is understood that the aforementioned terminals 1, 2, 3, and 4 are only for illustrative purposes. When performing the above-mentioned distribution network line fault location method, any terminal (such as the aforementioned terminals 1, 2, 3, and 4) can be the first terminal described in the first aspect or the second terminal described in the second aspect.

[0089] Taking terminal 2 as an example, the fault location method for distribution network lines in this application is described in detail below. The M side and N side of each distribution network switch are defined sequentially according to the line topology. The M side being the upstream side and the N side being the downstream side is existing technology in power system topology. Following the overall principle of topological order from front to back, the M side and N side are divided as follows: the N side of distribution network switch FS1 is distribution network switch FS2; the M1 side of distribution network switch FS2 is distribution network switch FS1, the M2 side is distribution network switch FS3, and the N side is distribution network switch FS4; the M1 side of distribution network switch FS3 is distribution network switch FS2; the M1 side of distribution network switch FS4 is distribution network switch FS2.

[0090] Taking terminal 2 as an example, the pre-set line lengths are Lm1 on the M1 side (which is the line length between switch FS2 and switch FS1), Lm2 on the M2 side (which is the line length between switch FS2 and switch FS3), and Ln on the N side (which is the line length between switch FS2 and switch FS4).

[0091] The traveling wave head time stamp T of the recording terminal 2 (that is, the first traveling wave head time stamp) is received by GOOSE from the adjacent traveling wave head time stamps sent by the M1 and M2 sides, namely Tm1 and Tm2 (that is, the two adjacent traveling wave head time stamps sent by the switches FS1 and FS3).

[0092] Terminal 2 communicates with adjacent terminals via GOOSE peer-to-peer communication, either wirelessly or via wired connection. Terminal 2 transmits a wavefront time stamp comprising a timestamp and a nanosecond value. It should be noted that in power systems, timestamps are typically accurate to the second; therefore, this embodiment further adds a time value accurate to the nanosecond, allowing the fault location to be determined using the nanosecond value. The time stamp transmitted by Terminal 2 via GOOSE contains a four-byte large-second value (i.e., the timestamp) and a four-byte small-second value (i.e., the nanosecond value), the meanings of which are clear.

[0093] Terminal 2 receives the timestamp via GOOSE. The M1 side receives the timestamp (large second value) and the M1 side receives the nanosecond value (small second value), the M2 side receives the timestamp (large second value) and the M2 side receives the nanosecond value (small second value), and the N side receives the timestamp (large second value) and the N side receives the nanosecond value (small second value).

[0094] Terminal 2 receives the traveling wave head time stamp Tn from the N side via GOOSE. The distance to terminal 2 corresponding to the M1 side can be calculated using the ranging formula. The distance from the fault point to terminal 2 is SLm1=1 / 2*(Lm1+V*(T-Tm1)). For terminal 3 on the M2 side, the distance from the fault point to terminal 2 is SLm2 = 1 / 2 * (Lm2 + V * (T - Tm2)); For terminal 4 on the N side, the distance from the fault point to terminal 2 is SLn = 1 / 2 * (Ln + V * (T - Tn)); If the calculated length is equal to the pre-set length, or the calculated length is 0, the fault point is outside this section. For example, if SLm1 = Lm1 or SLm1 = 0, the fault point is outside the M1 side zone of FS2 switch (corresponding to the distribution network line section from FS1 to FS2); if SLm1 is not equal to the pre-set Lm1 (generally SLm1 is less than Lm1), the fault location is within the M1 side zone of FS2 switch (corresponding to the distribution network line section from FS1 to FS2). For example, if SLn = Ln or SLn = 0, the fault point is outside the N side zone of FS2 switch (corresponding to the distribution network line section from FS2 to FS4); if SLn is not equal to the pre-set Ln (generally SLn is less than Ln), the fault location is within the N side zone of FS2 switch (corresponding to the distribution network line section from FS2 to FS4). Thus, through the above steps, this embodiment of the application can more accurately determine the distribution network line section where the fault point is located.

[0095] In practical applications, to avoid errors caused by timescale accuracy and other factors, this application embodiment can further set a corresponding error threshold value d. For example, if (Lm1-d)≤SLm1≤(Lm1+d), it is determined that SLm1=Lm1; if (0-d)≤SLm1≤(0+d), it is determined that SLm1=0. That is to say, according to the distance measurement result of the above distance measurement formula, if the distance measurement result is within the length range of the corresponding distribution network line segment including the error threshold value, it is determined that the distance measurement result is equal to the length of the distribution network line segment; if the distance measurement result is within the length range of the corresponding zero value including the error threshold value, it is determined that the distance measurement result is equal to the zero value; then the fault point is not within the distribution network line segment.

[0096] Please continue reading. Figure 4This application embodiment performs ranging compensation based on the interactive analysis results, and the comprehensive principle for determining the fault location is as follows: The meanings of FS1, FS2, FS3, and FS4 have been explained above. Examples are as follows: FS1 receives input from outside the N-side region and outputs from outside the M1-side region of FS2; FS1 receives input from inside the N-side region and outputs from inside the M1-side region of FS2; FS1's N-side ranging receives ranging output from the M1-side region of FS2. FS2 receives input from outside the M1-side region and outputs from outside the N-side region of FS1; FS2 receives input from inside the M1-side region and outputs from inside the N-side region of FS1; FS1's M1-side ranging receives ranging output from the N-side region of FS1. FS2 receives input from outside the M2-side region and outputs from outside the M1-side region of FS3; FS2 receives input from inside the M2-side region and outputs from inside the M1-side region of FS3; FS2's M2-side ranging receives ranging output from the M1-side region of FS3. FS3 receives signals from outside the M1 side region and outputs signals from outside the M2 side region of FS2; FS3 receives signals from inside the M1 side region and outputs signals from inside the M2 side region of FS2; FS3's M1 side ranging receiver receives signals from the M2 side ranging receiver of FS2. FS4 receives signals from outside the M1 side region and outputs signals from outside the N side region of FS2; FS4's M1 side receiving signals from inside the M1 side region and outputs signals from inside the N side region of FS2; FS1's N side ranging receiver receives signals from the M1 side ranging receiver of FS2.

[0097] If the fault point occurs between FS1 and FS2, for FS1, the local side determines it is within the N-side zone, and the received input value within the N-side zone is 1, so the fault point is within the N-side zone of FS1 switch, at a distance of Sln from FS1 switch; for FS2, the local side determines it is within the M1-side zone, and the received input value within the M1-side zone is 1, so the fault point is within the M1-side zone of FS2 switch, at a distance of Slm1 from FS2 switch; for FS3, the local side determines it is outside the M1-side zone, and the received input value outside the M1-side zone is 1, so the fault point is outside the M1-side zone of FS3 switch and does not belong to the fault section; for FS4, the local side determines it is outside the M1-side zone, and the received input value outside the M1-side zone is 1, so the fault point is outside the M1-side zone of FS4 switch and does not belong to the fault section.

[0098] This application embodiment, through on-site analysis and interaction, comprehensively analyzes and reliably determines the fault section. Compensation is achieved using the distance measurement information from the switches on both sides within the fault section. For example, in the case of a fault between switches FS1 and FS2, the following calculation is made: ΔL = (SLn + SLm1 - Ln) / 2, where SLn is the distance measurement result from the N-side of switch FS1, SLm1 is the distance measurement result received from the N-side switch FS2, and Ln is the N-side line length set by switch FS1. The final distance S from the fault point to switch FS1 is then S = SLn - ΔL. Compensation is performed based on the analysis results to ultimately determine the distance of the fault point from this side, resulting in more accurate fault location. Regarding Ln, which is the N-side line length set by switch FS1, this is based on terminal 1 or switch FS1. Ln refers to the line length between switches FS1 and FS2, which actually varies depending on the different reference switches in the distribution network topology.

[0099] Please see Figure 5 , Figure 5 This is a schematic diagram illustrating another application embodiment of the power distribution line fault location method provided in some embodiments of this application. In practice, Figure 5 To simplify the system fault diagram of the distribution network, switch FS1 is located near the power supply side, and FS1-FS5 are all distribution line switches. Each switch is equipped with fault detection terminals 1-5. Figure 5 The example illustrates two failure modes, one of which occurs when... Figure 5 As shown at F1, another fault occurs at... Figure 5 As shown at F2. If a phase-to-phase short-circuit fault occurs at F1, the intelligent distributed traveling wave fault location according to this application embodiment is performed through the following steps: Step 1: For switches FS1, FS2, FS3, FS4, and FS5, the corresponding terminals 1, 2, 3, 4, and 5 respectively collect the power frequency three-phase voltage and three-phase current of the corresponding switches, and the high frequency collecting of the traveling wave current of the corresponding switches. Step 2: Switches FS1-FS5 and corresponding terminals 1-5 synchronize based on GPS / BeiDou time and buffer 100ms of high-frequency sampled traveling wave current; Step 3: If a phase-to-phase fault occurs at F1, switch FS1 is close to the power supply side. Switch FS1 starts by a sudden current change to determine the time and phase of the fault; switches FS2, FS3, FS4, and FS5 start by a sudden voltage change to determine the time and phase of the fault. Step 4: Switches FS1, FS2, FS3, FS4, and FS5 search backwards for their respective 20ms high-frequency sampling traveling wave currents based on the fault time and phase, take the maximum value as the first traveling wave front, and record the corresponding wave front time stamp. Step 5: Switch FS1 and switch FS2 exchange wavefront time stamp information based on wireless or wired GOOSE peer-to-peer communication; switch FS2 and switch FS3 exchange wavefront time stamp information based on wireless or wired communication; switch FS2 and switch FS4 exchange wavefront time stamp information based on wireless or wired communication; switch FS4 and switch FS5 exchange wavefront time stamp information based on wireless or wired communication. Step 6: Switches FS3, FS4, and FS5 determine the fault location outside this section by comprehensively analyzing and comparing the wavefront information of adjacent switches; switches FS1 and FS2 determine the fault location within this section by comprehensively analyzing and comparing the wavefront information of adjacent switches. Step 7: Based on the switch interaction analysis results, it is further determined that the fault belongs to the area where both switches FS1 and FS2 are located. Through comprehensive compensation using the distance measurement results of switches FS1 and FS2, the fault point is determined to be located at SLn-△L on switch FS1 and at SLm1-△L on switch FS2. The formula for the above fault point is only for illustrative purposes; this application embodiment further performs distance compensation. Here, Ln represents the N-side line length set by switch FS1, which is based on terminal 1 or switch FS1. Ln here refers to the line length between switches FS1 and FS2.

[0100] Please continue reading. Figure 5 If a single-phase ground fault occurs at F2, the intelligent distributed traveling wave ranging of this application embodiment is performed through the following steps: Step 1: Collect the power frequency three-phase voltage and three-phase current of the corresponding terminals 1-5 of switches FS1-FS5, and collect the traveling wave current of the corresponding switches at high frequency; Step 2: Terminals 1-5 synchronize time using GPS / BeiDou and buffer 100ms of high-frequency sampled traveling wave current; Step 3: A single-phase ground fault occurs at F2. Switches FS1-FS5 are activated by voltage surge to determine the time and phase of the fault. Step 4: Switches FS1-FS5 look up their respective 20ms high-frequency sampling traveling wave currents back to the fault time and phase, take the maximum value as the first traveling wave front, and determine the corresponding wave front time stamp; Step 5: Switch FS1 and switch FS2 communicate with each other via GOOSE to exchange wavefront time stamp information; switch FS2 and switch FS3 communicate with each other via GOOSE to exchange wavefront time stamp information; switch FS2 and switch FS4 communicate with each other via GOOSE to exchange wavefront time stamp information; switch FS4 and switch FS5 communicate with each other via GOOSE to exchange wavefront time stamp information. Step 6: Based on the comprehensive analysis and comparison of the wavefront information of adjacent switches FS1, FS2, and FS3, the fault point is outside this section; based on the comprehensive analysis and comparison of the wavefront information of adjacent switches FS4 and FS5, the fault point is within this section. Step 7: Terminals 4 and 5 interact and analyze the results. Both switches FS4 and FS5 determine that the fault belongs to the area, and the fault point is located at SLn-△L on FS4 and SLm1-△L on FS5. The formula for the above fault point is only for illustration; distance compensation has been further performed in this embodiment. Here, Ln is the N-side line length set by switch FS4, which is based on terminal 4 or switch FS4. Ln here refers to the line length between switches FS4 and FS5.

[0101] Fourthly, such as Figure 6 As shown in the illustration, this application also provides a power distribution line fault location system, applied to a first terminal installed on one side of a power distribution line, and a second terminal installed on the other side of the power distribution line, comprising: The wavefront determination module 601 is used to determine whether a first fault has occurred in the distribution network line based on a first electrical signal on one side of the distribution network line. If a first fault has occurred, the corresponding first traveling wavefront information is determined based on the first moment of the first fault and a second electrical signal on one side of the distribution network line. The information receiving module 602 is used to receive the second traveling wave header information sent by the second terminal, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after judging that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line; The fault determination module 603 is used to determine whether the fault is within the distribution network line segment based on the first traveling wave wavefront information and the second traveling wave wavefront information if the first fault and the second fault are the same fault, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal; The fault location module 604 is used to determine the fault location based on the first traveling wave wavefront information, the second traveling wave wavefront information, the traveling wave propagation speed, and the line length of the distribution network line segment if the fault is located within the distribution network line segment.

[0102] The aforementioned power distribution line fault location system determines whether a fault has occurred in the power distribution line by measuring the voltage and current on one side of the line. If a fault occurs, it determines the corresponding first traveling wave front information based on the traveling wave current on one side of the line and receives the second traveling wave front information from the other side. Based on the first and second traveling wave front information, it analyzes whether the fault point is within the power distribution line segment. If it is, it can accurately locate the fault location based on the first and second traveling wave front information, the traveling wave propagation speed, and the length of the power distribution line. This system achieves accurate fault location of the power distribution line without relying on a master station, through interactive communication between local terminals.

[0103] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the power distribution network line fault location system described above can be referred to the corresponding process in the aforementioned power distribution network line fault location method, and will not be elaborated further here.

[0104] To better implement the fault location method for distribution network lines in this application, please refer to... Figure 7 , Figure 7 This is a schematic diagram of the terminal structure provided in an embodiment of this application. This application also provides a terminal that integrates any of the power distribution network line fault location systems provided in this application. The terminal may include components such as a processor 501 with one or more processing cores, a memory 502 with one or more computer-readable storage media, a power supply 503, a sampling component 504, and a communication module 505. Specifically, in this application, the processor 501 in the terminal can load executable files corresponding to processes of one or more application programs into the memory 502 according to the following instructions, and the processor 501 runs the application programs stored in the memory 502 to achieve various functions, as follows: The first electrical signal on one side of the power distribution line determines whether a first fault has occurred in the power distribution line. If a first fault has occurred, the corresponding first traveling wave front information is determined based on the first moment of the first fault and the second electrical signal on one side of the power distribution line. The second traveling wave header information sent by the second terminal is received, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after the second terminal judges that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line; If the first fault and the second fault are the same fault, then it is determined whether the fault is within the distribution network line segment based on the first traveling wavefront information and the second traveling wavefront information, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal; If the fault is located within the distribution network line segment, the fault location is determined based on the first traveling wave front information, the second traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment.

[0105] Those skilled in the art will understand that Figure 7 The device structure shown does not constitute a limitation on the device. The terminal may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0106] The processor 501 in this terminal is the control center of the device. It connects various parts of the device via various interfaces and lines, and performs various functions and processes data by running or executing software programs and / or unit modules stored in the memory 502, and by calling data stored in the memory 502, thereby providing overall monitoring of the terminal. Optionally, the processor 501 may include one or more processing cores; the processor 501 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor. Preferably, the processor 501 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and applications, and the modem processor mainly handles wireless communication. It is understood that the aforementioned modem processor may not be integrated into the processor 501.

[0107] The memory 502 can be used to store software programs and modules. The processor 501 executes various functional applications and data processing by running the software programs and modules stored in the memory 502. The memory 502 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, applications required for at least one function, etc.; the data storage area may store data created according to the use of the terminal, etc. In addition, the memory 502 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, the memory 502 may also include a memory controller to provide the processor 501 with access to the memory 502.

[0108] The terminal may also include a power supply 503 that supplies power to the various components. Preferably, the power supply 503 is logically connected to the processor 501 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The power supply 503 may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

[0109] The terminal may also include a sampling component 504 and a communication module 505. The sampling component 504 can be used for power frequency sampling of the three-phase voltage and three-phase current of the distribution network line; it can also be used for high-frequency sampling of the three-phase traveling wave current of the distribution network line; this is prior art and will not be described in detail here. The communication module 505 can be used to interact with adjacent terminals using GOOSE peer-to-peer communication technology. The communication module 505 can communicate with the communication module 505 of adjacent terminals in a wired or wireless manner.

[0110] Those skilled in the art will understand that all or part of the steps in the various methods described above can be accomplished by instructions, or by controlling related hardware with instructions. These instructions can be stored in a computer-readable storage medium and loaded and executed by the processor 501.

[0111] Therefore, this application provides a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk, etc. Computer instructions are stored thereon, and these computer instructions are loaded by processor 501 to execute the steps in any of the power distribution line fault location methods provided in this application. For example, when the computer instructions are executed by processor 501, they perform the following functions: The first electrical signal on one side of the power distribution line determines whether a first fault has occurred in the power distribution line. If a first fault has occurred, the corresponding first traveling wave front information is determined based on the first moment of the first fault and the second electrical signal on one side of the power distribution line. The second traveling wave header information sent by the second terminal is received, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after the second terminal judges that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line; If the first fault and the second fault are the same fault, then it is determined whether the fault is within the distribution network line segment based on the first traveling wavefront information and the second traveling wavefront information, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal; If the fault is located within the distribution network line segment, the fault location is determined based on the first traveling wave front information, the second traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment.

[0112] The computer instructions stored in the computer-readable storage medium can execute the present application as follows. Figure 1 , Figure 2 or Figure 3 Corresponding to the steps in the power distribution line fault location method in any embodiment, the present application can be implemented as described above. Figure 1 , Figure 2 or Figure 3 For details on the beneficial effects that the fault location method for distribution network lines can achieve in any embodiment, please refer to the preceding description, which will not be repeated here.

[0113] In summary, the power distribution network line fault location method, system, terminal, and storage medium provided in this application rely on power frequency sampling to determine whether a fault has occurred and determine the fault time through power frequency sampling. This can accurately determine the fault time and avoid the problem of frequent activation of traveling wave components caused by existing high-frequency sampling of traveling wave current for fault judgment, greatly reducing the computational requirements. The fault section is determined by exchanging the wavefront timestamps of adjacent switches through the GOOSE protocol, and the ranging information of the switches in the fault section is further used to compensate for the ranging results on both sides of the fault, accurately locating the fault location of the line fault. This enables fault location without relying on the master station system.

[0114] The above provides a detailed description of a method, system, terminal, and storage medium for locating faults in a power distribution network, as provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and its core ideas. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for locating faults in a power distribution network line, applied to a first terminal installed on one side of the power distribution network line, wherein a second terminal is installed on the other side of the power distribution network line, characterized in that, The method includes: The first electrical signal on one side of the power distribution line determines whether a first fault has occurred in the power distribution line. If a first fault has occurred, the corresponding first traveling wave front information is determined based on the first moment of the first fault and the second electrical signal on one side of the power distribution line. The second traveling wave header information sent by the second terminal is received, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after the second terminal judges that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line; If the first fault and the second fault are the same fault, then it is determined whether the fault is within the distribution network line segment based on the first traveling wavefront information and the second traveling wavefront information, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal; If the fault is located within the distribution network line segment, the fault location is determined based on the first traveling wave front information, the second traveling wave front information, the traveling wave propagation speed, and the line length of the distribution network line segment.

2. The method according to claim 1, characterized in that, The first electrical signal includes: a first three-phase voltage and a first three-phase current; The step of determining whether a first fault has occurred in the distribution network line based on a first electrical signal on one side of the distribution network line includes: If the first three-phase current experiences a continuous current change, then it is determined that the distribution network line has experienced a first fault, and the first moment corresponding to the first fault is determined. If the first three-phase current does not experience continuous current changes, but the first three-phase voltage experiences continuous voltage changes, then it is determined that the distribution network line has experienced a first fault, and the first moment corresponding to the first fault is determined.

3. The method according to claim 1, characterized in that, The second electrical signal includes: a first three-phase traveling wave current; the first traveling wave front information includes a first traveling wave front time stamp; determining the corresponding first traveling wave front information based on the first moment of the first fault and the second electrical signal on one side of the distribution network line includes: The first three-phase traveling wave current on one side of the distribution network line is sampled to obtain the corresponding first three-phase traveling wave current dataset. The first three-phase traveling wave current dataset includes the current value of the first three-phase traveling wave current within a first preset time period and the corresponding sampling time scale. The first target sampling time scale corresponding to the first three-phase traveling wave current data set is determined based on the first time point; The first three-phase traveling wave current data subset is determined in the first three-phase traveling wave current dataset according to the first target sampling time mark. The first three-phase traveling wave current data subset is the current value of the first three-phase traveling wave current in the first three-phase traveling wave current dataset within the second preset time mark from the first target sampling time mark to the previous second preset time mark and the corresponding sampling time mark. The second preset time mark is less than or equal to the first preset time mark. The sampling time stamp corresponding to the maximum current value in the first three-phase traveling wave current data subset is determined as the first traveling wave wavefront time stamp.

4. The method according to claim 1, characterized in that, If the first fault and the second fault are the same fault, it includes: If the second traveling wave header information sent by the second terminal is received within the third preset time period after the first moment, then the first fault and the second fault are determined to be the same fault.

5. The method according to claim 3, characterized in that, The second traveling wavefront information includes the second traveling wavefront time stamp; the step of determining whether the fault is within the distribution network segment based on the first traveling wavefront information and the second traveling wavefront information includes: The first traveling wave distance measurement result of the first terminal is determined based on the first traveling wave wavefront timescale, the second traveling wave wavefront timescale, the traveling wave propagation speed, and the line length of the distribution network line segment; If the first traveling wave ranging result is less than the line length, then the fault is determined to be within the distribution network line segment.

6. The method according to claim 5, characterized in that, The method further includes: sending the first traveling wave wavefront time stamp to the second terminal, so that the second terminal determines the second traveling wave ranging result of the fault distance to the second terminal based on the second traveling wave wavefront time stamp, the first traveling wave wavefront time stamp, the traveling wave propagation speed and the line length; The step of determining the fault location based on the first traveling wavefront information, the second traveling wavefront information, the traveling wave propagation speed, and the line length of the distribution network segment includes: Receive the second traveling wave ranging result sent by the second terminal; The corresponding ranging compensation value is determined based on the first traveling wave ranging result, the second traveling wave ranging result, and the line length. The fault location is determined based on the first traveling wave ranging result and the ranging compensation value.

7. A method for locating faults in a power distribution network line, characterized in that, The method, applied to a second terminal installed on the other side of a power distribution network line, wherein a first terminal is installed on one side of the power distribution network line, includes: The second fault is determined based on the third electrical signal on the other side of the power distribution line. If the second fault occurs, the corresponding second traveling wavefront information is determined based on the fourth electrical signal on the other side of the power distribution line and the second time of the second fault. The system receives first traveling wave header information sent by the first terminal, wherein the first traveling wave header information is determined by the first terminal based on the first electrical signal on one side of the power distribution line to determine that a first fault has occurred in the power distribution line, and based on the first moment of the first fault and the second electrical signal on one side of the power distribution line. If the first fault and the second fault are the same fault, then it is determined whether the fault is within the distribution network line segment based on the second traveling wavefront information and the first traveling wavefront information, wherein the distribution network line segment is the distribution network line between the second terminal and the first terminal; If the fault is located within the distribution network line segment, the fault location is determined based on the second traveling wavefront information, the first traveling wavefront information, the traveling wave propagation speed, and the line length of the distribution network line segment.

8. A fault location system for a power distribution network line, applied to a first terminal installed on one side of a power distribution network line, wherein a second terminal is installed on the other side of the power distribution network line, characterized in that, include: The wavefront determination module is used to determine whether a first fault has occurred in the distribution network line based on a first electrical signal on one side of the distribution network line. If a first fault has occurred, the corresponding first traveling wavefront information is determined based on the first moment of the first fault and a second electrical signal on one side of the distribution network line. The information receiving module is used to receive the second traveling wave header information sent by the second terminal, wherein the second traveling wave header information is determined by the second terminal based on the second time of the second fault and the fourth electrical signal on the other side of the distribution network line after judging that the distribution network line has a second fault based on the third electrical signal on the other side of the distribution network line; The fault determination module is used to determine whether the fault is within the distribution network line segment based on the first traveling wave wavefront information and the second traveling wave wavefront information if the first fault and the second fault are the same fault, wherein the distribution network line segment is the distribution network line between the first terminal and the second terminal; The fault location module is used to determine the fault location based on the first traveling wave wavefront information, the second traveling wave wavefront information, the traveling wave propagation speed, and the line length of the distribution network line segment if the fault is located within the distribution network line segment.

9. A terminal, characterized in that, The device includes a sampling component, a memory, and a processor. The sampling component and the memory are both connected to the processor. The sampling component is used to sample the electrical signals of the power distribution network lines. The memory stores a computer program, which, when executed by the processor, implements the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, It stores a computer program, which is loaded by a processor to perform the steps of the method according to any one of claims 1-7.

Images