A method, device and medium for locating a fault of a multi-branch hybrid line by using a traveling wave

Abstract

The application discloses a multi-branch hybrid line traveling wave fault positioning method, device and medium, and relates to the technical field of measuring electric variables. The method comprises the following steps: based on a traveling wave synchronous monitoring device arranged on a monitoring node in a hybrid line, collecting a high-frequency transient signal generated in the hybrid line, and extracting a signal feature corresponding to the high-frequency transient signal; according to the signal feature and the signal energy of the high-frequency transient signal, pre-identifying a fault of the hybrid line, so as to determine a pre-fault event generated in the hybrid line and a pre-fault section corresponding to the pre-fault event; in the case that the signal feature exceeds a preset fault starting threshold, determining that a traveling wave is generated in the hybrid line, and acquiring a wave head arrival time corresponding to a traveling wave signal received by the monitoring node; according to a line topological relation of the hybrid line and the order of the wave head arrival times corresponding to different monitoring nodes, determining a fault branch in which the traveling wave is generated in the pre-fault section.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of measuring electrical variables, and in particular to a traveling wave fault location method for a multi-branch hybrid line, a device and a medium. BACKGROUND

[0002] With the expansion of urban power grid scale and the improvement of power supply reliability, multi-branch and hybrid line structures are increasingly common in distribution networks. The topology of the hybrid line is complex, there are many T-junctions, and the power flow direction may change with the load, which brings great challenges to fault monitoring and positioning.

[0003] Existing fault location methods mainly rely on impedance methods or traditional traveling wave methods for fault location. The impedance method calculates the line impedance by measuring the voltage and current after the fault, and then calculates the fault distance. This method is susceptible to factors such as transition resistance, system operating mode, and inaccurate line parameters. For multi-branch lines, it is not possible to directly determine which specific branch the fault occurs in. The traveling wave method uses the traveling wave signal generated at the moment of fault to locate the fault. The time stamp of the traveling wave arriving at the measurement point is used for calculation. If a single-ended traveling wave method is used, it is necessary to identify the initial traveling wave from the fault point and the reflected traveling wave from the opposite side. In a multi-branch line, due to the existence of a large number of T-junctions, extremely complex refraction and reflection waves will be generated, making it difficult to accurately distinguish the initial wave front and the reflected wave front, and the positioning reliability is poor. Although the double-ended traveling wave method has high accuracy, it requires the deployment of synchronous monitoring devices at both ends of the line, which is costly and has insufficient coverage for multi-branch structures. In addition, existing methods focus on post-fault positioning and lack early warning capabilities for early fault signs, making it impossible to transition from passive repair to active maintenance. SUMMARY

[0004] To solve the above problems, the present application provides a traveling wave fault location method for a multi-branch hybrid line, comprising:

[0005] Based on the traveling wave synchronous monitoring device deployed on the monitoring node in the hybrid line, the high-frequency transient signal generated in the hybrid line is collected, and the signal features corresponding to the high-frequency transient signal are extracted;

[0006] According to the signal features and the signal energy of the high-frequency transient signal, the hybrid line is pre-identified for fault to determine the pre-fault event generated in the hybrid line and the pre-fault section corresponding to the pre-fault event;

[0007] In the case where the signal features exceed the preset fault starting threshold, it is determined that the hybrid line generates a traveling wave, and the wave head arrival time corresponding to the traveling wave signal received by the monitoring node is obtained;

[0008] According to the line topological relation of the mixed line and the sequence of the wave head arrival time corresponding to different monitoring nodes, a fault branch in the pre-fault section generating the traveling wave is determined.

[0009] In an implementation manner of the present application, according to the line topological relation of the mixed line and the sequence of the wave head arrival time corresponding to different monitoring nodes, a fault branch in the pre-fault section generating the traveling wave is determined, specifically comprising:

[0010] From the monitoring nodes receiving the traveling wave signals, a target monitoring node with the earliest wave arrival time and adjacent monitoring nodes of the target monitoring node are selected; wherein the adjacent monitoring nodes at least include any one or more of the following: upstream backbone line monitoring nodes, downstream backbone line monitoring nodes and branch monitoring nodes;

[0011] According to the line topological relation of the mixed line, the node distance between the adjacent monitoring nodes and the target monitoring node is determined;

[0012] According to the sequence of the wave head arrival time in the target monitoring node and the adjacent monitoring nodes, the node distance is used to analyze the propagation path of the traveling wave signal;

[0013] Through the propagation path, a fault branch in the pre-fault section generating the traveling wave is determined.

[0014] In an implementation manner of the present application, according to the signal feature and the signal energy of the high-frequency transient signal, a fault pre-identification is performed on the mixed line to determine a pre-fault event generated in the mixed line and a pre-fault section corresponding to the pre-fault event, specifically comprising:

[0015] The mixed line is subjected to fault pre-identification to match the signal feature with a pre-set early warning signal feature library, and the similarity between the signal feature and each early warning signal feature in the early warning signal feature library is determined; wherein the early warning signal feature includes amplitude, polarity, steepness and energy distribution;

[0016] In the case that the similarity exceeds a pre-set threshold and the signal energy of the high-frequency transient signal is less than a pre-set multiple of a real fault signal energy threshold, it is determined that a pre-fault event is generated in the mixed line;

[0017] A specified monitoring node in the monitoring nodes acquiring the high-frequency transient signal is determined;

[0018] According to the receiving time of the high-frequency transient signal received by the specified monitoring node, a pre-fault section in the mixed line generating the pre-fault event is obtained by inversion.

[0019] In an implementation form of the application, the pre-fault section in the hybrid line that generates the pre-fault event is inversely derived according to the receiving time of the high-frequency transient signal received by the specified monitoring node, and specifically comprises:

[0020] The hybrid line is divided into a plurality of candidate hidden danger points according to a fixed distance; wherein each line section is provided with a candidate hidden danger point;

[0021] Based on the shortest propagation path from the candidate hidden danger point to each specified monitoring node, the theoretical arrival time of the high-frequency transient signal to each specified monitoring node when the candidate hidden danger point generates the high-frequency transient signal is calculated;

[0022] According to the error value between the receiving time of the high-frequency transient signal and the theoretical arrival time, the line section in which the candidate hidden danger point with an error value less than a preset error is selected as the pre-fault section in the hybrid line that generates the pre-fault event.

[0023] In an implementation form of the application, after determining the fault branch in the pre-fault section that generates the traveling wave, the method further comprises:

[0024] Determining the branch line length of the fault branch and the wave head arrival time corresponding to the traveling wave at both ends of the fault branch;

[0025] Obtaining the propagation speed of the traveling wave, and calculating the deviation distance between the midpoint and the fault point of the fault branch according to the difference between the wave head arrival times at both ends and the propagation speed;

[0026] According to the mean value of the deviation distance and the branch line length, the distance between the fault point and both ends of the fault branch is determined.

[0027] In an implementation form of the application, before collecting the high-frequency transient signal generated in the hybrid line, the method further comprises:

[0028] Obtaining the topological structure data of the hybrid line;

[0029] Based on the topological structure data, pre-selecting the key nodes in the hybrid line; wherein the key nodes at least include the line head, the tail end and all T-branch points;

[0030] Performing dead zone analysis on the pre-selected key nodes to identify the dead zone section that cannot be located by all traveling wave synchronous monitoring devices;

[0031] Adding a supplementary node to the dead zone section, and determining the monitoring node of the hybrid line that needs to deploy the traveling wave synchronous monitoring device according to the positions of the supplementary node and the key node.

[0032] In an implementation form of the application, after determining the monitoring nodes of the traveling wave synchronization monitoring devices to be deployed on the mixed line according to the positions of the supplementary nodes and the key nodes, the method further comprises:

[0033] determining the coverage of the monitoring nodes on the mixed line; wherein the coverage refers to the proportion of the line capable of being positioned by at least two traveling wave synchronization monitoring devices on the mixed line;

[0034] in the case that the coverage is greater than a preset coverage threshold and the number of the monitoring nodes exceeds a preset upper limit value, the monitoring nodes are removed in ascending order of the contribution of the monitoring nodes to the coverage until the monitoring nodes after removal meet the preset upper limit value.

[0035] In an implementation form of the application, the fault starting threshold corresponding to the signal feature is lower than the fault feature threshold corresponding to the signal feature of the mixed line in the fault case.

[0036] The embodiments of the application provide a traveling wave fault locating device for a multi-branch mixed line, the device comprising:

[0037] at least one processor;

[0038] and a memory in communication connection with the at least one processor;

[0039] wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the traveling wave fault locating method for a multi-branch mixed line according to any one of the above.

[0040] The embodiments of the application provide a non-volatile computer storage medium storing computer executable instructions, the computer executable instructions being configured to:

[0041] the traveling wave fault locating method for a multi-branch mixed line according to any one of the above.

[0042] The traveling wave fault locating method for a multi-branch mixed line provided by the application can bring the following beneficial effects:

[0043] By deploying the traveling wave synchronization monitoring device in the multi-node deployment, a monitoring network capable of covering the whole line is formed, solving the problems of insufficient coverage and branch identification difficulty caused by insufficient devices in the double-end traveling wave method. Secondly, by analyzing the signal characteristics and signal energy of the high-frequency transient signal, the pre-fault event with weak energy and the traveling wave signal with huge energy can be distinguished, so as to identify the pre-fault event and preliminarily locate the pre-fault section before the permanent fault occurs, realizing the early warning of the early-stage line fault. When the fault occurs, the sequence of the wave head arrival time of the multi-node and the line topology relationship are used for logical reasoning to accurately locate the fault branch, effectively improving the fault location accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0044] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0045] Figure 1 A flowchart of a traveling wave fault location method for a multi-branch hybrid line provided by an embodiment of the present application;

[0046] Figure 2 A structural diagram of a traveling wave fault location device for a multi-branch hybrid line provided by an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described in detail below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0048] The technical scheme provided by each embodiment of the present application will be described in detail below in combination with the drawings.

[0049] As shown in Figure 1 A traveling wave fault location method for a multi-branch hybrid line provided by an embodiment of the present application, comprising:

[0050] S101: Based on the traveling wave synchronization monitoring device deployed on the monitoring node in the hybrid line, the high-frequency transient signal generated in the hybrid line is collected, and the signal characteristics corresponding to the high-frequency transient signal are extracted.

[0051] The mixed line refers to a complex power distribution network connected by different types of lines (such as a mixed overhead line and cable) or different voltage grade lines. In an actual power system, when a short circuit or ground fault occurs at a certain location of the line, a sudden energy wave with a huge energy will be generated. In order to capture abnormal signals, it is usually necessary to set up a traveling wave synchronous monitoring device on the mixed line to detect possible faults in the line. The difference from the traditional traveling wave fault detection method is that the embodiments of the application no longer set up monitoring devices at one end or both ends of the line, but deploy traveling wave synchronous monitoring devices at multiple monitoring nodes on the mixed line. The monitoring nodes here can be the first end of the line, the last end of the line, T-branch points, main load points, etc. By setting multiple monitoring nodes in the mixed line, the deployed traveling wave synchronous monitoring devices can cover multiple branch lines and multiple nodes. By collecting high-frequency transient signals at each monitoring node, the complex mixed power grid structure can be adapted. Compared with the traditional double-end traveling wave method which only collects signals at both ends of the line, the signal collection range is more extensive, and multi-point early warning can be realized, thereby improving the identification capability of fault hidden dangers.

[0052] The high-frequency transient signal refers to an electromagnetic signal excited by a sharp and temporary change in electric field or magnetic field energy caused by certain events during the operation of the power line. By identifying the high-frequency transient signal, it can be identified whether a substantial fault occurs in the mixed line. According to the source and energy level, the high-frequency transient signal mainly includes two types of signals. One is a partial discharge signal with weak energy caused by early insulation defects such as insulation deterioration and tree discharge, and the other is a traveling wave signal with huge energy generated when a permanent fault such as short circuit or grounding occurs in the line. After the high-frequency transient signal is collected by the traveling wave synchronous monitoring device, the signal needs to be denoised, and the signal features corresponding to the high-frequency transient signal are extracted. The signal features include amplitude, polarity, steepness and energy distribution. By analyzing the signal energy and signal features corresponding to the signal features, the possible fault hidden danger in the line can be identified in the case of identifying weak transient signals (i.e. partial discharge signals), and the line section where the fault may occur is preliminarily located. When the traveling wave signal is captured, the precise location of the fault position is determined in combination with the fault section preliminarily located before. This can not only identify and preliminarily locate the fault section at the early stage of the fault to help prevent the line fault in advance, but also quickly locate the fault position in the locked fault section when the real fault occurs, greatly shorten the fault investigation and repair time, and improve the operation and maintenance efficiency.

[0053] In one embodiment, the traveling wave synchronization monitoring device needs to be arranged into multiple monitoring nodes in the mixed line, and the selection of the monitoring nodes needs to adapt to the characteristics of different lines, and the traveling wave synchronization monitoring device is preferentially deployed at key positions such as the first end, the end of the line, the T-connection branch point and the main load node, so as to ensure the overall coverage of each branch of the mixed line. Therefore, in order to determine the optimal position of deploying a limited number of monitoring devices on a complex line, the optimal balance between cost and performance needs to be achieved.

[0054] Specifically, the topological structure data of the mixed line is acquired, the topological structure data is a model describing the electrical connection relationship of the power line, including the length, electrical parameters, branch number and connection relationship between nodes (such as substations, towers, branch boxes) of the line section. Based on the topological structure data, first, the pre-selection of the key nodes on the line is performed, the key nodes need to cover all main power flow directions and branch starting points, and at least include the first end, the end of the line and all T-connection branch points. However, the above pre-selected key nodes may have a monitoring blind area, and therefore, the key nodes need to be analyzed for the dead zone. The dead zone section refers to a line section in which when a fault occurs in the section, due to the symmetry of the traveling wave propagation path or the defects of the monitoring point layout, the time difference of the initial traveling wave received by different monitoring points is zero or cannot be distinguished, so that the fault location cannot be uniquely determined. For example, in the middle region of the line section between two adjacent monitoring nodes, the time of the fault traveling wave reaching the two nodes is almost the same, so it is difficult to determine which end the fault is close to. In order to solve this problem, a supplementary node needs to be added to the dead zone section, that is, in the identified dead zone section, one or several new positions are selected as the supplementary node. Finally, all the pre-selected key nodes and the supplementary nodes determined after analysis are merged, so as to determine the monitoring nodes of the traveling wave synchronization monitoring device deployed on the mixed line, and form a monitoring node deployment scheme without blind area.

[0055] The traditional double-end method only deploys synchronization devices at both ends of the line. In a complex multi-branch line, only deploying monitoring devices at both ends will completely fail to locate the branches, and in order to solve the branch positioning problem, a set of independent double-end detection system needs to be configured for each branch, resulting in a sharp rise in total cost and complex system. The embodiments of the present application deploy monitoring devices at multiple nodes, and through this networked deployment method, the complex multi-branch line is divided into multiple monitorable sections, without the need to configure a set of independent double-end system for each independent branch, so as to achieve full coverage of the line while avoiding the increase in the number of devices and effectively controlling the deployment cost.

[0056] In one embodiment, after the preliminary formation of the monitoring node deployment scheme, the number of monitoring nodes needs to be optimized in consideration of the deployment cost to ensure that each line section can be covered for detection and the economic benefit is maximized. In optimizing the deployment scheme, the ideal degree of the deployment scheme needs to be evaluated through the coverage, which refers to the proportion of the lines in the mixed line that can be positioned by at least two traveling wave synchronous monitoring devices. Therefore, by traversing the coverage of each position in the mixed line by the traveling wave synchronous monitoring device, the coverage of the mixed line by the monitoring nodes in the current deployment scheme can be determined. It is judged whether the coverage is greater than a preset coverage threshold. If it exceeds the preset coverage threshold, it means that the monitoring performance of the monitoring nodes set at this time has reached the standard. However, if the number of monitoring nodes exceeds the preset upper limit value, the current deployment scheme may have a performance surplus and resource waste, and the number of monitoring nodes needs to be refined.

[0057] In refining the monitoring nodes, instead of deleting the nodes at will, the nodes need to be deleted in order based on the importance of each monitoring node. Specifically, the contribution degree of each monitoring node to the overall coverage is evaluated. The calculation method is that the coverage of the monitoring nodes is recalculated assuming that the node is removed, and the degree of the drop is the contribution degree of the node. In ascending order of the contribution degree, the monitoring nodes with the weakest impact on the global positioning ability are removed in turn. The number of remaining nodes and the current coverage are checked in real time after removing each monitoring node, and the optimization process is continuously performed until the number of monitoring nodes is refined to within the preset upper limit value. Through this dynamic optimization, the monitoring node deployment scheme with the lowest cost and the fewest nodes can be found under the premise of strictly meeting the predetermined positioning performance requirements, and the economic benefit is maximized.

[0058] S102: According to the signal feature and the signal energy of the high-frequency transient signal, the mixed line is pre-identified for fault to determine the pre-fault event generated in the mixed line and the pre-fault section corresponding to the pre-fault event.

[0059] After the signal feature of the high-frequency transient signal is extracted, the mixed line can be pre-identified for fault according to the signal feature and the signal energy. The pre-identification for fault refers to that before the fault develops into a real fault, the possible fault hidden danger is found in advance by analyzing the feature of the high-frequency transient signal. Such a fault hidden danger is called a pre-fault event, which refers to an event that may have a fault hidden danger but has not yet produced a substantial fault. By identifying whether the mixed line has a possible pre-fault event, the pre-fault section where the pre-fault event may occur is preliminarily positioned, so that appropriate preventive measures can be taken at the initial stage of the fault to avoid further expansion and deterioration of the fault.

[0060] In one embodiment, before the pre-fault identification is performed, it is necessary to establish a typical early warning signal feature library through experiments or simulations. The early warning signal feature library includes the traveling wave waveform features of partial discharge signals caused by insulator deterioration, tree discharge, loose hardware, etc. The extracted signal features are matched with the preset early warning signal feature library, and the similarity of the signal features and each early warning signal feature in the early warning signal feature library is calculated to determine whether there is a potential fault hazard in the hybrid line. The early warning signal feature library contains signal features of various known fault types, such as amplitude, polarity, steepness, and energy distribution, etc. When the similarity of multiple signal features exceeds a preset threshold, or the weighted comprehensive similarity of multiple signal features is greater than a preset threshold, it is preliminarily determined that there is an anomaly in the line. Multi-feature joint determination can effectively improve the accuracy and reliability of fault pre-identification, and avoid false alarms caused by single feature misjudgment. After preliminarily determining that there is an anomaly in the line, the signal energy of the high-frequency transient signal is further determined. Since the traveling wave signal energy generated by a real permanent fault is huge, and the partial discharge signal energy generated by an early insulation defect is weak, if the signal energy of the high-frequency transient signal is less than a preset multiple of the real fault signal energy threshold, it indicates that the signal fault feature is obvious but the energy value is much lower than the fault threshold. At this time, due to insufficient signal energy, it can be determined that the hybrid line has not produced a substantial fault, and the event is finally determined to be a pre-fault event, i.e. a fault hazard indicating deterioration of the insulation state, but not causing a substantial short circuit or ground fault.

[0061] After the hybrid line has a fault hazard, multiple monitoring nodes can detect abnormal signals. Therefore, after determining the pre-fault event, the specified monitoring node that acquires the high-frequency transient signal from the monitoring nodes is first determined, and then the arrival time stamp of the high-frequency transient signal recorded by the specified monitoring node is used to preliminarily calculate the approximate range of the hazard source in the complex multi-branch hybrid line, so as to obtain the pre-fault section that produces the pre-fault event, capture and identify the weak signal generated by the early defect, realize the leap from post-processing to pre-prevention, and provide the operation and maintenance personnel with an early warning report containing specific location information to guide them to carry out accurate inspection and maintenance.

[0062] In one embodiment, the embodiments of the present application perform space-time inversion by signal receiving time and theoretical arrival time of high-frequency transient signals to determine the specific location of the pre-fault section. In power line fault analysis, candidate hazard points are virtual set of spatial position points where faults or hazard signals may occur, and the topology of the entire hybrid line is discretized at fixed distances, for example, every 10 meters or 50 meters, to generate a large number of uniformly distributed virtual points. Each such virtual point is a candidate hazard point. By dividing the candidate hazard points, the continuous line positioning problem can be converted into a screening problem of a limited number of discrete points, effectively reducing the difficulty of fault location.

[0063] After establishing the candidate hazard point set, the shortest propagation path from each candidate hazard point to each designated monitoring node (i.e., the actual physical location where the traveling wave synchronous monitoring device is deployed) is determined according to the line topology of the hybrid line. The shortest propagation path refers to the path with the shortest electrical distance through which the high-frequency transient signal propagates from the candidate hazard point to the monitoring node. Since the propagation speed of the traveling wave in different types of lines is known, where the overhead line is close to the speed of light and the cable is about half the speed of light, the theoretical arrival time of the signal at each designated monitoring node can be calculated when the high-frequency transient signal is generated from any candidate hazard point, according to the length of the shortest propagation path and the wave speed. The theoretical arrival times of all designated monitoring nodes form a theoretical arrival time sequence for the candidate hazard point.

[0064] After obtaining the high-frequency transient signal generated by the actual pre-fault event of the hybrid line, the actual receiving time of the high-frequency transient signal arriving at each designated monitoring node is determined. The receiving times of all designated monitoring nodes collectively form a receiving time sequence. The receiving time sequence and the theoretical arrival time sequence of all candidate hazard points are compared one by one, and the comparison index is the error value, which is usually the root mean square error of the difference between the two time sequences. After obtaining the comparison result, the point with the most matching theoretical time sequence and actual receiving time sequence needs to be determined among all candidate hazard points, i.e., the candidate hazard point with an error value less than a preset error. Finally, the line section where this selected candidate hazard point is located is determined as the pre-fault section, thereby realizing the spatial positioning of the hazard source such as insulation defects.

[0065] After actually monitoring the high-frequency transient signal, only the signal receiving time recorded by each designated monitoring node needs to be quickly matched with the pre-stored theoretical arrival time library. By finding the candidate hazard point with the smallest error, the pre-fault section where the hazard source is most likely to exist can be directly determined. This converts the complex fault signal propagation analysis problem into a numerical matching problem, which can effectively adapt to the complex topology of multi-branch hybrid lines and overcome the positioning ambiguity problem near branch points of traditional methods.

[0066] S103: In the case that the signal feature exceeds the preset fault starting threshold, it is determined that the hybrid line generates a traveling wave, and the wave head arrival time corresponding to the traveling wave signal received by the monitoring node is obtained.

[0067] The above process describes how to locate the pre-fault section in the case that the hybrid line generates a partial discharge signal. When the pre-fault event continues to develop into a substantial fault, the fault point will generate a powerful sudden traveling wave. The criterion for determining whether the hybrid line generates a traveling wave is whether the signal feature exceeds the preset fault starting threshold. The fault starting threshold is a signal feature threshold value for determining whether a substantial fault occurs in the hybrid line, which needs to be lower than the fault feature threshold value corresponding to the signal feature of the hybrid line in the fault case. This is because at the initial stage of the fault, the signal feature may not have reached the fault feature threshold value, but it has obviously exceeded the normal range. At this time, if the fault feature threshold value is used as the starting condition, the best opportunity for fault location will be missed. Therefore, the preset fault starting threshold should be set between the normal signal feature and the fault feature threshold value, so as to ensure that the positioning process can be triggered at the initial stage of the fault. When the high-frequency transient signal feature collected by the monitoring node exceeds the preset fault starting threshold, it is determined that a traveling wave is generated in the hybrid line. At this time, the wave head arrival time of the traveling wave signal received by each monitoring node needs to be recorded immediately. The wave head arrival time is the time when the traveling wave signal first arrives at the monitoring node. According to the wave head arrival time and the pre-fault section detected before that may have a fault, the actual fault point can be quickly located.

[0068] S104: According to the line topology relationship of the hybrid line and the order of the wave head arrival time corresponding to different monitoring nodes, the fault branch in the pre-fault section that generates the traveling wave is determined.

[0069] All the wave head arrival times collected by the monitoring nodes are collected. According to the topology information of the hybrid line, the connection relationship between different monitoring nodes and the signal propagation path can be determined. Since the traveling wave propagates along the topology structure of the line when it propagates in the hybrid line, the order of the wave head arrival time received by different monitoring nodes can reflect the path and direction of signal propagation. By analyzing the order of the wave head arrival time corresponding to different monitoring nodes, the fault branch in the pre-fault section that generates the traveling wave can be determined.

[0070] In one embodiment, the line section where the monitoring node first and secondly detects the traveling wave signal is the main line or branch where the fault occurs. Firstly, from the monitoring nodes receiving the traveling wave signal, the target monitoring node with the earliest arrival time of the traveling wave and the adjacent monitoring nodes of the target monitoring node are selected. The adjacent monitoring nodes include at least any one or more of the following: upstream main line monitoring nodes, downstream main line monitoring nodes and branch monitoring nodes. According to the line topology relationship of the hybrid line, the node distance between the adjacent monitoring nodes and the target monitoring node, i.e. the electrical length of the line, is determined, which is the basis for the travel time calculation. Subsequently, the arrival time sequence of the wave front of the target monitoring node and each of its adjacent monitoring nodes is compared. According to the principle of traveling wave propagation, the signal will propagate to all branches when passing through each T junction during the propagation process. Therefore, the fault point must be located in the line area covered by the target monitoring node. By comparing the time sequence and node distance, the source direction of the signal can be deduced. For example, if the fault occurs on a branch, the traveling wave will first arrive at the monitoring node at the end of the branch and then propagate to the adjacent nodes on the main line. If the fault occurs on the downstream main line of the target node, the downstream adjacent node will receive the signal earlier than the upstream adjacent node. Through this time sequence logical reasoning, it can be clearly analyzed that the traveling wave signal propagates to the target node from which direction, thereby determining the propagation path of the fault branch.

[0071] The traditional double-end method relies on the time difference between the two ends for calculation. Once the number of branches increases and the signal propagation path becomes complex, this method fails. The embodiments of the present application are based on the wave front arrival time sequence of the entire monitoring network. By comparing the arrival sequence of the initial traveling wave detected by multiple monitoring nodes and combining the known line topology, it can be uniquely deduced that the fault occurs in which specific branch. The positioning problem is transformed from two-point distance measurement to network time sequence analysis, which perfectly adapts to the multi-branch structure of the hybrid line.

[0072] In one embodiment, after determining the fault branch, the location of the fault point also needs to be accurately positioned, thereby providing accurate maintenance recommendations for the maintenance personnel. Specifically, assuming that the fault point is located on the fault branch between monitoring node M and monitoring node N, the branch line length L of the fault branch is determined, as well as the wave front arrival times and of the traveling wave at the two ends of the fault branch, respectively. The propagation speed V of the traveling wave is obtained. According to the difference between the wave front arrival times at the two ends and the propagation speed, the deviation distance between the midpoint of the fault branch and the fault point is calculated. Then, according to the deviation distance and the average of the branch line length, the distances of the fault point from the two ends of the fault branch can be determined. The above calculation process can be represented by the following formula:

[0073]

[0074] In the above formula, the offset distance between the midpoint of the fault branch and the fault point is represented as The final calculated is the distance from the monitoring node M. If the distance between the fault point and the monitoring node N is to be calculated, replace and in the above formula.

[0075] By using the above traveling wave-based propagation time for fault location, the positioning accuracy is effectively improved, which is not affected by the transition resistance, system impedance, load fluctuation and fault type. Moreover, the physical phenomenon of the traveling wave propagating from the fault point to both sides is irrelevant to the direction of the power frequency flow in the line, and the fault location logic and accuracy are not affected by the change of the line flow, which has strong adaptability.

[0076] The above is the method embodiment provided by the present application. Based on the same idea, some embodiments of the present application also provide a device and a non-volatile computer storage medium corresponding to the above method.

[0077] Figure 2 A structure diagram of a traveling wave fault location device for a multi-branch hybrid line provided by an embodiment of the present application. As shown in Figure 2 , it comprises:

[0078] at least one processor; and

[0079] a memory in communication connection with the at least one processor; wherein

[0080] The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the traveling wave fault location method for a multi-branch hybrid line according to any one of the above.

[0081] An embodiment of the present application provides a non-volatile computer storage medium, which stores computer executable instructions, and the computer executable instructions are configured to:

[0082] perform the traveling wave fault location method for a multi-branch hybrid line according to any one of the above.

[0083] Each of the embodiments in the present application is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment mainly describes the difference from other embodiments. In particular, for the device and medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the description of the method embodiments.

[0084] The device and medium provided by the embodiments of the present application are one-to-one corresponding, and therefore the device and medium also have similar beneficial technical effects to the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the device and medium will not be described here again.

[0085] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. In addition, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0086] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in one or more flows and / or blocks.

[0087] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in one or more flows and / or blocks.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in one or more flows and / or blocks.

[0089] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memories.

[0090] Memory can include non-persistent memory and / or volatile memory, random access memory (RAM), and / or non-volatile memory, e.g., read only memory (ROM) or flash memory, among others. Memory is an example of computer readable media.

[0091] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile discs (DVDs) or other optical storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0092] It should also be noted that the terms "comprising," "including," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0093] The above description is merely illustrative of the application, and not restrictive. Various modifications and changes can become apparent to those skilled in the art. The disclosure is given only by way of example and various changes in form and detail can be made without departing from the spirit, and the scope or ambit of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the scope of the claims of the application.

Claims

1. A method for locating traveling wave faults in a multi-branch hybrid line, characterized in that, The method includes: Based on the traveling wave synchronous monitoring device deployed on the monitoring node in the hybrid line, high-frequency transient signals generated in the hybrid line are collected, and the signal features corresponding to the high-frequency transient signals are extracted. Based on the signal characteristics and the signal energy of the high-frequency transient signal, the hybrid line is pre-identified to determine the pre-fault events generated in the hybrid line and the pre-fault sections corresponding to the pre-fault events. If the signal characteristics are detected to exceed a preset fault initiation threshold, it is determined that the hybrid line generates a traveling wave, and the arrival time of the wavefront corresponding to the traveling wave signal received by the monitoring node is obtained. Based on the line topology of the hybrid line and the order of wavefront arrival times corresponding to different monitoring nodes, the fault branch that generates the traveling wave in the pre-fault section is determined. Based on the signal characteristics and the signal energy of the high-frequency transient signal, fault pre-identification is performed on the hybrid line to determine the pre-fault events generated in the hybrid line and the pre-fault sections corresponding to the pre-fault events, specifically including: Fault pre-identification is performed on the hybrid line to match the signal features with a preset warning signal feature library and determine the similarity between the signal features and each warning signal feature in the warning signal feature library; wherein, the warning signal features include amplitude, polarity, steepness and energy distribution; If the similarity exceeds a preset threshold and the signal energy of the high-frequency transient signal is less than a preset multiple of the energy threshold of the real fault signal, a pre-fault event is determined to have occurred in the hybrid line. Identify the designated monitoring node among the monitoring nodes that acquired the high-frequency transient signal; Based on the reception time of the high-frequency transient signal received by the designated monitoring node, the pre-fault section in the hybrid line that generates the pre-fault event is obtained by inversion. Based on the reception time of the high-frequency transient signal received by the designated monitoring node, the pre-fault section in the hybrid line that generates the pre-fault event is retrieved, specifically including: The hybrid line is divided into multiple candidate potential hazard points according to a fixed distance; wherein, each line section has one candidate potential hazard point; Based on the shortest propagation path from the candidate potential hazard point to each designated monitoring node, calculate the theoretical arrival time of the high-frequency transient signal from the candidate potential hazard point to each designated monitoring node when the high-frequency transient signal is generated. Based on the error between the received time of the high-frequency transient signal and the theoretical arrival time, the line section where the candidate potential hazard point with the error value is less than the preset error is selected as the pre-fault section in the hybrid line where the pre-fault event occurs.

2. The traveling wave fault location method for a multi-branch hybrid line according to claim 1, characterized in that, Based on the line topology of the hybrid line and the order of wavefront arrival times at different monitoring nodes, the fault branch that generates the traveling wave in the pre-fault section is determined, specifically including: From the monitoring nodes that receive the traveling wave signal, select the target monitoring node with the earliest arrival time of the traveling wave and the adjacent monitoring nodes of the target monitoring node; wherein, the adjacent monitoring nodes include at least one or more of the following: upstream main line monitoring nodes, downstream main line monitoring nodes, and branch monitoring nodes; Based on the line topology of the hybrid line, determine the node distance between the adjacent monitoring node and the target monitoring node; Based on the order of arrival times of the wavefronts of the target monitoring node and the adjacent monitoring nodes, and according to the node distance, the propagation path of the traveling wave signal is analyzed. The fault branch that generates the traveling wave in the pre-fault section is determined through the propagation path.

3. The traveling wave fault location method for a multi-branch hybrid line according to claim 1, characterized in that, After determining the fault branch in the pre-fault section that generates the traveling wave, the method further includes: Determine the branch line length of the faulty branch, and the arrival time of the wavefronts of the traveling wave at both ends of the faulty branch; The propagation speed of the traveling wave is obtained, and the deviation distance between the midpoint of the fault branch and the fault point is calculated based on the difference in the arrival time of the wavefronts at both ends and the propagation speed. The distance between the fault point and both ends of the faulty branch is determined based on the average of the deviation distance and the branch line length.

4. The traveling wave fault location method for a multi-branch hybrid line according to claim 1, characterized in that, Before acquiring the high-frequency transient signal generated in the hybrid circuit, the method further includes: Obtain the topology data of the hybrid lines; Based on the topology data, key nodes in the hybrid line are pre-selected; wherein, the key nodes include at least the beginning and end of the line and all T-junction branch points; Dead zone analysis was performed on the pre-selected key nodes to identify dead zone sections that could not be located by any traveling wave synchronous monitoring device. Supplementary nodes are added to the dead zone section, and the monitoring nodes on the hybrid line that require the deployment of traveling wave synchronization monitoring devices are determined based on the positions of the supplementary nodes and the key nodes.

5. The traveling wave fault location method for a multi-branch hybrid line according to claim 4, characterized in that, After determining the monitoring nodes on the hybrid line where traveling wave synchronization monitoring devices need to be deployed based on the locations of the supplementary nodes and the key nodes, the method further includes: Determine the coverage of the monitoring node over the hybrid line; wherein, the coverage refers to the proportion of the hybrid line that can be located by at least two traveling wave synchronous monitoring devices; If the coverage exceeds a preset coverage threshold and the number of monitoring nodes exceeds a preset upper limit, the monitoring nodes are removed sequentially in ascending order of their contribution to the coverage, until the number of removed monitoring nodes meets the preset upper limit.

6. The traveling wave fault location method for a multi-branch hybrid line according to claim 1, characterized in that, The fault initiation threshold corresponding to the signal feature is lower than the fault feature threshold corresponding to the signal feature in the case of a fault in the hybrid line.

7. A traveling wave fault location device for a multi-branch hybrid line, characterized in that, The device includes: At least one processor; And, a memory communicatively connected to the at least one processor; The memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform a traveling wave fault location method for a multi-branch hybrid line as described in any one of claims 1-6.

8. A non-volatile computer storage medium storing computer-executable instructions, characterized in that, The computer-executable instructions are set as follows: A traveling wave fault location method for a multi-branch hybrid line as described in any one of claims 1-6.

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