A distributed power transmission line fault accurate positioning method and system

Abstract

The present application relates to the technical field of power transmission line fault detection and positioning, in particular to a kind of distributed power transmission line fault accurate positioning method and system, the method and system are by obtaining measuring point information, line topology information and fault traveling wave data, determine the interval and initial measuring point set where fault is, extract candidate traveling wave head, generate candidate fault traveling wave event set, form event wave head combination and calculate isogenic reliability value and measuring point contribution degree value group, according to this dynamic access control and carry out fault positioning processing, the present application is by determining the interval and initial measuring point set where fault is, extract candidate traveling wave head and generate candidate fault traveling wave event set, calculate isogenic reliability value and measuring point contribution degree value group to implement dynamic access control, improve the reliability, stability and adaptability of positioning processing under complex fault scenario.

Description

Technical Field

[0001] This invention relates to the field of power transmission line fault detection and location technology, and more specifically, to a method and system for accurate location of distributed power transmission line faults. Background Technology

[0002] Transmission lines bear the responsibility of transmitting electricity over long distances. They are widely distributed and operate in complex environments, susceptible to faults caused by factors such as lightning strikes, icing, pollution flashover, tree obstructions, external damage, and insulation aging. To promptly pinpoint fault locations, narrow down inspection areas, and improve power restoration efficiency, existing technologies typically employ impedance ranging, traveling wave ranging, and distributed ranging methods for transmission line fault location. Among these, traveling wave ranging utilizes the characteristic of transient traveling waves generated at the moment of a fault propagating along the line. By calculating the time difference in arrival of the traveling waves detected at different measuring points, it can estimate the fault location, offering advantages such as fast response speed and applicability to long-distance line location.

[0003] With the deployment of distributed ranging terminals along transmission lines, multiple measuring points can simultaneously collect fault traveling wave data with time stamps and measuring point markers, providing a data foundation for fault section identification and refined location based on line topology information. In practical applications, if the initial traveling wave fronts detected by each measuring point are clear, have a consistent source, and have relatively stable propagation speeds, a relatively reliable fault location result can be obtained based on the arrival time difference between adjacent measuring points or measuring points at both ends of the section.

[0004] However, the actual fault process of transmission lines is quite complex. Faults may be accompanied by multiple discharges, intermittent arcing, insulation flashover reignition, or complex reflection and refraction phenomena, resulting in multiple candidate traveling wavefronts within the preset observation time window. Candidate traveling wavefronts detected at different measuring points may not all originate from the same initial traveling wave of the fault. They may also exhibit arrival time shifts, polarity differences, and inconsistent energy change rates due to propagation paths, propagation modes, measuring point timing status, noise interference, or wavefront extraction errors. If location calculations rely solely on the first wavefront, the wavefront with the largest amplitude, or a fixed combination of measuring points, non-homogeneous wavefronts may be included in the same location process, thus affecting the stability of the fault point calculation results.

[0005] Furthermore, the propagation speed of traveling waves cannot be simply considered a fixed value in all scenarios. Factors such as line structure, conductor parameters, medium conditions near the fault, propagation mode, and the location of the measuring point can all cause the actual traveling wave speed near the fault to differ from the preset wave speed. When there are many candidate wavefronts, unclear wavefront homology, or weak contributions from some measuring points, how to select credible events from multiple candidate fault traveling wave events, how to form reliable event wavefront combinations, how to evaluate the contribution of each measuring point to homology judgment and dynamic wave speed calculation, and based on this, decide whether to enter the precise location process, are problems that need further resolution in distributed transmission line fault location.

[0006] Based on this, the present invention proposes a method and system for accurate fault location of distributed transmission lines. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method and system for accurate location of faults in distributed transmission lines.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for precise fault location in distributed transmission lines includes:

[0010] Step 1: Obtain the measurement point information, line topology information, and fault traveling wave data with time stamps and measurement point marks corresponding to multiple distributed ranging terminals deployed along the transmission line;

[0011] Step 2: Based on the fault traveling wave data, measurement point information and line topology information, determine the fault section. Based on the first and second fault sides of the fault section, determine the initial measurement point set from the measurement points corresponding to multiple distributed ranging terminals. Within the preset observation time window, extract multiple candidate traveling wave fronts with corresponding arrival times and traveling wave front polarities from the fault traveling wave data corresponding to each measurement point in the initial measurement point set.

[0012] Step 3: Calculate multiple discharge density values ​​based on the multiple candidate traveling wave fronts corresponding to each measuring point in the initial measuring point set, and then generate a set of candidate fault traveling wave events.

[0013] Step 4: Based on the candidate fault traveling wave event set and the multiple candidate traveling wave waveheads corresponding to each measuring point in the initial measuring point set, form an event wavehead combination corresponding to the candidate fault traveling wave event, and calculate the homogeneity confidence value and measuring point contribution value group corresponding to the event wavehead combination.

[0014] Step 5: Based on the co-origin confidence value and measurement point contribution value group corresponding to the event wavefront combination, perform dynamic access control on the measurement points, candidate fault traveling wave events, and event wavefront combinations participating in dynamic wave velocity calculation to obtain the dynamic access control results; determine whether the dynamic wave velocity calculation conditions are met based on the dynamic access control results, and perform fault location processing based on the judgment results.

[0015] In one embodiment, step two, determining the initial measurement point set includes: determining the fault location interval based on the arrival time of the traveling wave front, the polarity of the traveling wave front, the measurement point information, and the line topology information in the fault traveling wave data; and selecting adjacent measurement points and next adjacent measurement points on the first fault side and the second fault side of the fault location interval, respectively, to form the initial measurement point set.

[0016] In one embodiment, step two, extracting multiple candidate traveling wave fronts, includes: performing denoising, bandpass filtering, and wavelet mode maxima detection on the fault traveling wave data corresponding to each measurement point in the initial measurement point set to obtain abrupt change points; and determining abrupt change points whose amplitude, energy change rate, and duration satisfy preset wave front criteria as candidate traveling wave fronts.

[0017] In one embodiment, step three, calculating the multiple discharge density value includes: calculating the multiple discharge density value based on the number of candidate traveling wavefronts at each measuring point in the initial measuring point set, the time interval between adjacent candidate traveling wavefronts, the rate of change of traveling wavefront energy, the aggregation degree of traveling wavefronts across measuring points, and the order perturbation degree of traveling wavefronts.

[0018] In one embodiment, step three, generating a candidate fault traveling wave event set, includes: comparing multiple discharge density values ​​with a first preset density threshold and a second preset density threshold, respectively; when the multiple discharge density values ​​are less than the first preset density threshold, dividing the fault traveling wave data within a preset observation time window into a single fault traveling wave event, and writing the single fault traveling wave event into the candidate fault traveling wave event set; when the multiple discharge density values ​​are not less than the second preset density threshold, splitting the fault traveling wave data within the preset observation time window into multiple fault traveling wave sub-events, and writing the multiple fault traveling wave sub-events into the candidate fault traveling wave event set.

[0019] In one embodiment, step three, generating a candidate fault traveling wave event set, further includes: when the multiple discharge density values ​​are not less than a first preset density threshold and less than a second preset density threshold, increasing the number of candidate traveling wave fronts participating in matching for each measurement point in the initial measurement point set, generating multiple enhanced candidate fault traveling wave events based on different candidate traveling wave front matching sequences, and writing the multiple enhanced candidate fault traveling wave events into the candidate fault traveling wave event set.

[0020] In one embodiment, step four, forming an event wavefront combination, includes: for each candidate fault traveling wave event in the candidate fault traveling wave event set, selecting candidate traveling wave wavefronts belonging to that candidate fault traveling wave event from each measurement point in the initial measurement point set, and forming an event wavefront combination.

[0021] In one embodiment, in step four, the co-origin confidence value is used to characterize the confidence level that the event wavefront combination belongs to the same candidate fault traveling wave event, the same fault initial traveling wave, the same propagation path, the same propagation mode, and the same time reference; the measurement point contribution value group includes the measurement point contribution value corresponding to each measurement point in the event wavefront combination, and the measurement point contribution value is used to characterize the degree of contribution of the corresponding measurement point to the co-origin confidence value.

[0022] In one embodiment, step five, the fault location processing based on the judgment result includes: if the dynamic wave velocity calculation conditions are met, determining the target fault traveling wave event, the target event wavefront combination, the target homogeneity confidence value, the target measurement point contribution value group, and the dynamic wave velocity calculation measurement point set, and then calculating the dynamic traveling wave velocity near the fault and the location of the fault point on the transmission line, and outputting the accurate fault location result; if the dynamic wave velocity calculation conditions are not met, outputting the fault location interval result and the non-homogeneous wavefront anomaly indicator.

[0023] In one embodiment, a distributed transmission line fault precise location system includes:

[0024] The data acquisition module is used to acquire measurement point information, line topology information, and fault traveling wave data with time stamps and measurement point marks corresponding to multiple distributed ranging terminals deployed along the transmission line.

[0025] The wavefront extraction module is used to determine the fault section based on fault traveling wave data, measurement point information and line topology information, determine the initial set of measurement points based on the first fault side and the second fault side of the fault section, and extract multiple candidate traveling wavefronts within a preset observation time window.

[0026] The event generation module is used to calculate multiple discharge density values ​​based on multiple candidate traveling wave fronts corresponding to each measuring point in the initial measuring point set, and then generate a set of candidate fault traveling wave events.

[0027] The combined calculation module is used to form a combination of event wavefronts corresponding to the candidate fault traveling wave events based on the candidate fault traveling wave event set and multiple candidate traveling wave wavefronts corresponding to each measuring point in the initial measuring point set, and to calculate the homogeneity confidence value and the measuring point contribution value group.

[0028] The location processing module is used to dynamically control the access of the measurement points, candidate fault traveling wave events, and event wavefront combinations participating in dynamic wave velocity calculation based on the same source confidence value and measurement point contribution value group, to determine whether the dynamic wave velocity calculation conditions are met, and to perform fault location processing.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention acquires measurement point information, line topology information, and fault traveling wave data with time stamps and measurement point markers from multiple distributed ranging terminals. After determining the fault location interval, it determines an initial measurement point set based on the first fault side and the second fault side. This enables the extraction range of candidate traveling wave fronts to match the fault location interval and line topology relationship, avoiding excessive participation of irrelevant measurement point data in subsequent calculations, thereby improving the targeting of fault traveling wave data screening and the basic reliability of fault location processing.

[0031] This invention extracts multiple candidate traveling wave fronts with corresponding arrival times and traveling wave front polarities from an initial set of measurement points within a preset observation time window, and further calculates multiple discharge density values ​​to generate a candidate fault traveling wave event set. This can distinguish and organize fault traveling wave events under conditions of multiple discharges, continuous reignitions, or dense appearance of wave fronts, reducing the risk of misselection caused by judging based on a single first wave front or a single amplitude feature, and improving the completeness and accuracy of candidate fault traveling wave event identification in complex fault traveling wave scenarios.

[0032] This invention forms event wavefront combinations corresponding to candidate fault traveling wave events, calculates the homogeneity confidence value and measurement point contribution value group corresponding to the event wavefront combinations, and then dynamically controls the access of measurement points, candidate fault traveling wave events, and event wavefront combinations participating in dynamic wave velocity calculation. It can perform accurate fault location when the dynamic wave velocity calculation conditions are met, and perform corresponding fault location processing when the dynamic wave velocity calculation conditions are not met. This not only improves the ability of non-homogeneous wavefronts and abnormal measurement points to suppress the location results, but also enhances the stability, reliability, and adaptability of distributed transmission line fault location under complex operating conditions. Attached Figure Description

[0033] Figure 1 This is an overall flowchart of a method for accurate fault location in distributed transmission lines according to an embodiment of the present invention;

[0034] Figure 2 This is a flowchart illustrating the determination of the initial measurement point set, extraction of candidate traveling wave fronts, and generation of candidate fault traveling wave event set in this embodiment of the invention.

[0035] Figure 3This is a flowchart of the event wavefront combination formation, the calculation of the homogeneity confidence value and the measurement point contribution value group, the dynamic access control and fault location processing in an embodiment of the present invention.

[0036] Figure 4 This is a structural block diagram of a distributed transmission line fault accurate location system according to an embodiment of the present invention. Detailed Implementation

[0037] Example 1: Refer to Figures 1 to 3 A method for precise fault location in distributed transmission lines, comprising:

[0038] Step 1: Obtain the measurement point information, line topology information, and fault traveling wave data with time stamps and measurement point marks corresponding to multiple distributed ranging terminals deployed along the transmission line.

[0039] In one specific implementation, multiple distributed ranging terminals are deployed along the beginning and end of the transmission line, as well as at line branch points, tension towers, or important tower locations. The measuring point information corresponding to each distributed ranging terminal is pre-recorded. This measuring point information includes the measuring point marker, the tower number where the measuring point is located, the mileage position of the measuring point in the line, the phase corresponding to the measuring point, the line length between the measuring point and adjacent measuring points, and the timing status of the distributed ranging terminal corresponding to the measuring point. Simultaneously, line topology information is acquired, including the connection relationship between the beginning and end of the transmission line, the branch connection relationship, the length of each line segment, the topological order between adjacent measuring points, and the attribution relationship of measuring points on different fault sides.

[0040] After a fault occurs, each distributed ranging terminal collects fault traveling wave data according to a unified time base, and adds time stamps and measurement point stamps to the collected fault traveling wave data, so that each segment of fault traveling wave data can be mapped to a specific measurement point and a specific collection time. For example, when a ground fault occurs on a transmission line between the fifth and sixth towers, the distributed ranging terminals deployed on both sides of the fault collect fault traveling wave data respectively, and write their respective measurement point stamps and time stamps obtained based on unified time synchronization into the fault traveling wave data, thereby forming a data foundation that can be used for subsequent determination of the fault location interval, determination of the initial measurement point set, and extraction of candidate traveling wave fronts.

[0041] Step 2: Based on the fault traveling wave data, measurement point information, and line topology information, determine the fault section. Based on the first and second fault sides of the fault section, determine an initial measurement point set from the measurement points corresponding to multiple distributed ranging terminals. Within a preset observation time window, extract multiple candidate traveling wave fronts with corresponding arrival times and traveling wave front polarities from the fault traveling wave data corresponding to each measurement point in the initial measurement point set.

[0042] In one specific implementation, based on the arrival time and polarity of the traveling wave front corresponding to each measuring point in the fault traveling wave data, combined with the measuring point markings recorded in the measuring point information, the mileage position of the measuring point in the line, and the connection relationship of adjacent measuring points recorded in the line topology information, the arrival order relationship and polarity correspondence formed at different measuring points when the fault traveling wave propagates along both sides of the transmission line are compared, thereby determining the fault interval; when the fault traveling wave data between two adjacent measuring points shows that the arrival time of the traveling wave front increases from that interval to both sides, and the polarity of the traveling wave front matches the propagation direction in the line topology information, the line segment between the two adjacent measuring points is determined as the fault interval;

[0043] In one specific implementation, to avoid determining the fault location interval solely based on a single candidate traveling wavefront or a single polarity relationship, the line segment between any two adjacent measuring points in the line topology information is first designated as a candidate fault interval, and a fault interval hypothesis is established for each candidate fault interval. For any candidate fault interval, the arrival time monotonicity score, polarity consistency score, and topological distance residual score are calculated, and then fused according to preset weights to obtain an interval confidence value. When the interval confidence value of a candidate fault interval is the highest and greater than a preset interval confidence threshold, the candidate fault interval is determined as the fault location interval; when there is no candidate fault interval with an interval confidence value greater than the preset interval confidence threshold, a fault interval pending confirmation flag is output, and the selection range of the initial measuring point set is expanded.

[0044] The interval confidence value is calculated as follows:

[0045]

[0046] in, For the first The interval confidence value of each candidate fault interval. To score the monotonicity of arrival time, For polarity consistency score, The score is the topological distance residual. , and For the corresponding weights, and satisfying The arrival time monotonicity score is used to characterize whether the arrival time of the traveling wave front at the measuring points on both sides of the candidate fault interval increases along the direction away from the candidate fault interval; the polarity consistency score is used to characterize whether the polarity of the candidate traveling wave front matches the propagation direction on both sides of the candidate fault interval; the topological distance residual score is used to characterize the degree of consistency between the actual arrival time difference and the theoretical arrival time difference calculated based on the topological distance of the measuring points.

[0047] After determining the fault location interval based on the interval confidence value, the fault location interval is further back-verified based on the candidate fault traveling wave event set and event wavehead combination. Specifically, the current fault location interval is taken as the first fault interval hypothesis, and the homology confidence value, root mean square of arrival time residual, and polarity consistency score of each candidate event wavehead combination under this fault interval hypothesis are calculated. If the homology confidence value of the target event wavehead combination is not less than the preset homology confidence threshold, and the root mean square of arrival time residual is not greater than the preset residual threshold, then the current fault location interval is maintained. If the above conditions are not met, other candidate fault intervals are selected as new fault interval hypotheses in descending order of interval confidence value, and candidate event matching and event wavehead combination calculation are performed again until a fault location interval that meets the admission conditions is determined. If all candidate fault intervals do not meet the admission conditions, a fault interval confirmation flag and a non-homologous wavehead anomaly flag are output, and the fault point is not entered into precise location.

[0048] Centered on the faulty section, the line direction on one side of the faulty section is defined as the first fault side, and the line direction on the other side of the faulty section is defined as the second fault side. On the first fault side, the nearest adjacent measuring point and the next nearest adjacent measuring point extending outwards are selected. Similarly, on the second fault side, the nearest adjacent measuring point and the next nearest adjacent measuring point extending outwards are selected. These measuring points together constitute the initial measuring point set. For example, if the faulty section is located between the third and fourth measuring points, the third and second measuring points can be used as the adjacent and next nearest adjacent measuring points on the first fault side, and the fourth and fifth measuring points can be used as the adjacent and next nearest adjacent measuring points on the second fault side. This constitutes an initial measuring point set that takes into account both the near-end wavefront characteristics and the far-end propagation verification characteristics on both sides of the fault.

[0049] In one specific implementation, after determining the initial set of measurement points, the initial abrupt change time in the fault traveling wave data is used as a reference. A preset observation time window is set before and after the initial abrupt change time, and the fault traveling wave data corresponding to each measurement point in the initial set of measurement points is read respectively. The fault traveling wave data corresponding to each measurement point is first denoised to reduce the influence of power frequency components, random interference and background noise on the identification of the traveling wave front. Then, bandpass filtering is performed so that the remaining fault traveling wave data is concentrated in the frequency range that can reflect the initial abrupt change characteristics of the fault traveling wave. Wavelet mode maxima detection is performed on the bandpass filtered fault traveling wave data to obtain multiple abrupt change points that can characterize the waveform abrupt change position, and the time position, amplitude change, energy change rate and duration corresponding to each abrupt change point are recorded.

[0050] For each abrupt change point, its amplitude is compared with a preset amplitude criterion, its energy change rate is compared with a preset energy change rate criterion, and its duration is determined to meet a preset wavefront criterion. When the amplitude, energy change rate, and duration of the abrupt change point all meet the preset wavefront criterion, the abrupt change point is identified as a candidate traveling wavefront, and the corresponding arrival time and traveling wavefront polarity are labeled for the candidate traveling wavefront. For example, when the third, second, fourth, and fifth measurement points constitute the initial measurement point set, the above processing can be performed on the fault traveling wave data of the four measurement points within the same preset observation time window, thereby obtaining multiple candidate traveling wavefronts with corresponding arrival times and traveling wavefront polarities at each measurement point, providing comparable wavefront objects for subsequent calculation of multiple discharge density values ​​and generation of candidate fault traveling wave event sets.

[0051] Step 3: Calculate multiple discharge density values ​​based on the multiple candidate traveling wave fronts corresponding to each measuring point in the initial measuring point set, and then generate a set of candidate fault traveling wave events.

[0052] In one specific implementation, multiple candidate traveling wave fronts corresponding to each measuring point in the initial measuring point set are sorted according to their corresponding arrival times. The number of candidate traveling wave fronts at each measuring point within a preset observation time window is counted, and the time interval between adjacent candidate traveling wave fronts within the same measuring point is calculated. When the number of candidate traveling wave fronts is greater, the time interval between adjacent candidate traveling wave fronts is shorter, and the energy change rate of the traveling wave fronts is more concentrated in a continuous abrupt change state, it indicates that the possibility of multiple discharges or continuous reignitions within the preset observation time window is higher. Further, based on the line topology information and measuring point information, propagation time compensation is performed on the corresponding arrival times of candidate traveling wave fronts at different measuring points. The candidate traveling wave fronts that fall within the same aggregation time range after compensation are used to calculate the cross-measuring point traveling wave front aggregation degree. At the same time, the actual detected arrival order of traveling wave fronts is compared with the theoretical arrival order inferred based on the fault location section, the first fault side, the second fault side, and the measuring point topology order to calculate the traveling wave front order perturbation degree.

[0053] The number of candidate traveling wavefronts, the time interval between adjacent candidate traveling wavefronts, the energy change rate of traveling wavefronts, the aggregation degree of traveling wavefronts across measurement points, and the order perturbation degree of traveling wavefronts can be normalized and then weighted and fused according to preset weights to obtain multiple discharge density values.

[0054] Let the initial set of measurement points be denoted as... ,in, The number of measuring points in the initial set of measuring points; [The remaining text appears to be incomplete and requires further context.] The set of candidate traveling wavefronts extracted within the preset observation time window is denoted as . ,in, For measuring points The corresponding number of candidate traveling wave waveheads. Each candidate traveling wave wavehead... At least include the corresponding arrival time Traveling wave head polarity Amplitude Energy change rate and duration .

[0055] The multiple discharge density value is denoted as And calculate as follows:

[0056]

[0057] in, For candidate traveling wave head quantity factors, For time interval density factor, The rate of change of energy, The wavefront convergence factor across measurement points. The wavefront sequence perturbation factor; and These are the corresponding weights, and they satisfy: Adjustments can be made based on historical fault traveling wave samples or on-site calibration samples. and The value of .

[0058] Candidate traveling wave head number factor Calculate as follows:

[0059]

[0060] in, , This represents the maximum number of candidate traveling wavefronts allowed to participate in the calculation within a preset observation time window, and .

[0061] Time interval density factor Calculate as follows:

[0062]

[0063] in, For measuring points The average arrival time interval of adjacent candidate traveling wavefronts within the same area; when the measuring point When the number of candidate traveling wavefronts is less than two, Set to the preset observation time window length; The time scale for determining multiple discharges; To prevent extremely small positive numbers with a denominator of zero.

[0064] Energy change rate factor Calculate as follows:

[0065]

[0066] in, The reference energy change rate is determined by historical fault traveling wave samples or field calibration samples; when no candidate traveling wave front is extracted at a certain measurement point, the energy change rate factor corresponding to that measurement point is zero.

[0067] Cross-measurement traveling wave wavefront convergence factor Calculate as follows:

[0068]

[0069] in, After propagation time compensation, they fall into the same aggregation time window The set of candidate traveling wave heads, For set The number of candidate traveling wavefronts corresponding to different measuring points. The arrival time after propagation time compensation. Calculate as follows:

[0070]

[0071] in, For measuring points The topological distance to the reference position, which can be the center of the faulty interval or the measurement point at the boundary of the interval; The initial traveling wave velocity is preset.

[0072] Traveling wave front sequence perturbation factor Calculate as follows:

[0073]

[0074] in, and The measuring points are respectively and measuring points The arrival times of representative candidate traveling wavefronts participating in the same aggregation time window judgment; and These are the theoretical arrival times calculated based on the fault location interval, the topological distance between the measuring points, and the preset initial traveling wave velocity. This is an indicator function that takes a value of 1 if the condition within the parentheses is true, and zero otherwise.

[0075] The first preset density threshold is denoted as The second preset density threshold is denoted as And satisfy In one embodiment, Desirable , Desirable Alternatively, it can be determined based on the distribution of multiple discharge density values ​​in historical single-fault traveling wave samples, multiple-discharge fault traveling wave samples, and insulation flashover reignition fault traveling wave samples, ensuring that most samples in the single-fault traveling wave samples are below [the required level]. And ensure that most samples in the multiple discharge fault traveling wave samples are not lower than .

[0076] when When, the fault traveling wave data within the preset observation time window is divided into single fault traveling wave events; when At that time, according to the candidate traveling wave front aggregation window after propagation time compensation, the fault traveling wave data is split into multiple fault traveling wave sub-events; when At that time, multiple candidate traveling wave fronts that meet the matching requirements of arrival time, traveling wave front polarity and energy change rate are selected from each measurement point. Different candidate traveling wave front matching sequences are constructed, and each candidate traveling wave front matching sequence that meets the propagation time residual requirement is determined as an enhanced candidate fault traveling wave event, thereby generating a set of candidate fault traveling wave events.

[0077] For example, when multiple candidate traveling wave fronts with high energy change rates are detected at the third, second, fourth, and fifth measuring points within the same preset observation time window, and after propagation time compensation, the multiple candidate traveling wave fronts repeatedly aggregate within a similar time range, and the actual arrival order of the traveling wave fronts is disturbed relative to the theoretical arrival order, a higher multiple discharge density value can be calculated to characterize the multiple discharge characteristics of the fault traveling wave data within the preset observation time window.

[0078] In one specific implementation, the calculated multiple discharge density values ​​are compared with a first preset density threshold and a second preset density threshold. The first preset density threshold and the second preset density threshold can be set based on the historical waveform statistics of single fault traveling waves, multiple discharge fault traveling waves, insulation flashover reignition fault traveling waves, and lightning backflashover fault traveling waves in the prior art. For example, the threshold values ​​can be determined based on the conventional distribution range of the number of candidate traveling wavefronts within a preset observation time window, the typical time interval between adjacent candidate traveling wavefronts, the abrupt change in the energy change rate of the traveling wavefronts, and the empirical boundary of the aggregation degree of traveling wavefronts across measurement points. The first preset density threshold is used to distinguish between single fault traveling wave events and suspected multiple discharge states, and the second preset density threshold is used to distinguish between suspected multiple discharge states and clear multiple discharge states.

[0079] When the multiple discharge density values ​​are less than the first preset density threshold, it indicates that the number of candidate traveling wave fronts is small within the preset observation time window, the time interval between adjacent candidate traveling wave fronts is relatively stable, and the traveling wave fronts across measurement points do not show repeated clustering characteristics. At this time, the fault traveling wave data within the preset observation time window is divided into a single fault traveling wave event, and the single fault traveling wave event is written into the candidate fault traveling wave event set. For example, after the fault occurs, each measurement point only detects one main mutation wave front on the same propagation sequence, then the traveling wave propagation process corresponding to the main mutation wave front is taken as a candidate fault traveling wave event.

[0080] When the multiple discharge density values ​​are not less than the second preset density threshold, it indicates that there are multiple wavefront clustering regions that are separated in time but have propagation correlation in space within the preset observation time window. At this time, according to the corresponding arrival time of the candidate traveling wave wavefront, the clustering position across measurement points, and the polarity consistency of the traveling wave wavefront, the fault traveling wave data within the preset observation time window is divided into multiple fault traveling wave sub-events, and the multiple fault traveling wave sub-events are written into the candidate fault traveling wave event set.

[0081] When the multiple discharge density values ​​are not less than the first preset density threshold and less than the second preset density threshold, it indicates that the fault traveling wave data is neither suitable to be directly identified as a single fault traveling wave event nor sufficient to be directly divided into multiple fault traveling wave sub-events. In this case, the number of candidate traveling wave fronts participating in the matching of each measuring point in the initial measuring point set is increased, and multiple enhanced candidate fault traveling wave events are generated based on different candidate traveling wave front matching sequences. Multiple enhanced candidate fault traveling wave events are written into the candidate fault traveling wave event set. For example, when two similar candidate traveling wave fronts are detected on both the first fault side and the second fault side, but their energy change rate difference is not significant, enhanced candidate fault traveling wave events dominated by the earlier candidate traveling wave fronts and enhanced candidate fault traveling wave events dominated by the later candidate traveling wave fronts can be constructed respectively, so that they can be further screened by the homogeneity confidence value and the measuring point contribution value group.

[0082] Step 4: Based on the candidate fault traveling wave event set and the multiple candidate traveling wave waveheads corresponding to each measurement point in the initial measurement point set, form an event wavehead combination corresponding to the candidate fault traveling wave event, and calculate the homogeneity confidence value and measurement point contribution value group corresponding to the event wavehead combination.

[0083] In one specific implementation, for each candidate fault traveling wave event in the candidate fault traveling wave event set, based on the event time range, event center time, traveling wave front polarity characteristics, and propagation sequence inferred from the line topology information, multiple candidate traveling wave fronts corresponding to each measuring point are retrieved one by one from the initial measuring point set; for each measuring point, the candidate traveling wave fronts whose arrival time falls within the allowable matching time range of the candidate fault traveling wave event, whose traveling wave front polarity matches the propagation direction of the candidate fault traveling wave event, and whose energy change rate meets the event association requirements are determined as candidate traveling wave fronts belonging to the candidate fault traveling wave event;

[0084] If multiple candidate traveling wave waveforms satisfying the conditions exist at the same measurement point, the priority selection is further determined based on the time deviation between the candidate traveling wave waveform and the event center time, the consistency of propagation time with candidate traveling wave waveforms at adjacent measurement points, and the degree of conformity with the theoretical arrival order. If no candidate traveling wave waveform fully satisfying the conditions is detected at a certain measurement point, the missing marker of that measurement point is retained or the candidate traveling wave waveform with the highest confidence is selected as the object to be verified. The candidate traveling wave waveforms selected from the first fault-side adjacent measurement points, the first fault-side second adjacent measurement points, the second fault-side adjacent measurement points, and the second fault-side second adjacent measurement points are combined according to the measurement point topology order to form the event waveform combination corresponding to the candidate fault traveling wave event. For example, when the time range of the candidate fault traveling wave event is 20 to 80 microseconds after the fault, and the initial measurement point set includes the second, third, fourth, and fifth measurement points, candidate traveling wave fronts that fall within this time range and meet the polarity and propagation order requirements can be selected from the four measurement points to form an event wave front combination. This ensures that the subsequent calculation of the same source confidence value and the measurement point contribution value group has a clear, complete, and traceable wave front correspondence.

[0085] In one specific implementation, for each formed event wavefront combination, based on the line topology information, the mileage position of each measuring point in the line, and the preset propagation speed of the traveling wave in the corresponding conductor propagation mode, the theoretical arrival time difference between each candidate traveling wave wavefront in the event wavefront combination is calculated and compared with the actual arrival time difference of each candidate traveling wave wavefront to obtain the time consistency deviation; at the same time, the traveling wave wavefront polarity, energy change rate, waveform abrupt change slope, and propagation direction of each candidate traveling wave wavefront are compared to make them correspond to the initial traveling wave consistency of the same fault, the consistency of the same propagation path, the consistency of the same propagation mode, and the consistency of the same time reference, respectively. Then, the above consistency results are normalized and fused according to preset weights to obtain the homogeneity confidence value. Among them, the smaller the time consistency deviation, the more matched the traveling wave wavefront polarity, the closer the energy change rate trend, and the more consistent the propagation path with the line topology information, the higher the homogeneity confidence value.

[0086] For each measurement point in the event wavefront combination, the local support degree of the candidate traveling wave wavefront corresponding to the measurement point to the same source confidence value is calculated. The local support degree includes at least the contribution of the arrival time of the measurement point to the overall time consistency, the contribution of the polarity of the traveling wave wavefront of the measurement point to the propagation direction determination, the contribution of the energy change rate of the measurement point to the initial traveling wave identification of the same fault, and the contribution of the timing state of the measurement point to the determination of the same time reference. The measurement point contribution value can be calculated by point-by-point elimination comparison method, that is, while retaining other candidate traveling wave wavefronts of measurement points, the target measurement point is temporarily eliminated, and the change in the same source confidence value before and after elimination is compared. The measurement point with the larger change is assigned a higher measurement point contribution value. The measurement point contribution value group is composed of the measurement point contribution values ​​corresponding to each measurement point.

[0087] For candidate fault traveling wave events The resulting event wavefront combination is denoted as ,in, The number of candidate traveling wavefronts participating in the same-origin confidence calculation in the event wavefront combination; candidate traveling wavefronts The corresponding actual arrival time, traveling wavefront polarity, energy change rate, and timing state value are denoted as follows: and .in, The value ranges from zero to one. When the time synchronization status of the corresponding measuring point is normal, it is taken as one; when the time synchronization status of the corresponding measuring point is abnormal, it is taken as zero; or it is a value between zero and one according to the time synchronization error level.

[0088] Based on the fault location section, the mileage position of the measuring point on the line, the line topology information, and the preset initial traveling wave velocity, the candidate traveling wave wavehead is calculated. Corresponding theoretical propagation distance Since the start time of the fault is unknown, the start time of the event is estimated as follows. :

[0089]

[0090] in, Preset initial traveling wave velocity. Candidate traveling wave fronts. Theoretical arrival time and arrival time residual Calculate them as follows:

[0091]

[0092]

[0093] Time Consistency Score Calculate as follows:

[0094]

[0095] in, The time tolerance is determined by the timing error of the distributed ranging terminal, the sampling interval, and the wavefront extraction error.

[0096] Polarity Consistency Score Calculate as follows:

[0097]

[0098] in, The theoretical traveling wavefront polarity is determined based on the propagation direction on both sides of the fault section and the line topology information.

[0099] Consistency score of energy change rate Calculate as follows:

[0100]

[0101] in, Let be the standard deviation of the rate of change of energy of each candidate traveling wavefront in the event wavefront combination. This represents the average rate of change of energy of each candidate traveling wavefront in the event wavefront combination. To prevent extremely small positive numbers with a denominator of zero.

[0102] Consistency score of propagation order Calculate as follows:

[0103]

[0104] Timing status score Calculate as follows:

[0105]

[0106] The same-source confidence value is denoted as And calculate as follows:

[0107]

[0108] in, and The weights are respectively for the time consistency score, polarity consistency score, energy change rate consistency score, propagation order consistency score, and timing status score, and satisfy the following:

[0109]

[0110] In one embodiment, and Can be taken separately and It can also be adjusted based on historical fault traveling wave samples, field calibration samples, or different line types.

[0111] For event wave head combination Any candidate traveling wave head The event wavehead combination after removing the candidate traveling wavehead is denoted as Measurement points Corresponding change in homology confidence Calculate as follows:

[0112]

[0113] in, This represents the homology confidence value corresponding to the complete event wavehead combination. To eliminate candidate traveling wave heads The recalculated homology confidence value was then obtained. Measurement point. Corresponding measurement point contribution value Calculate as follows:

[0114]

[0115] The contribution value of each measuring point This constitutes a group of contribution values ​​for the measuring points. If If the value is less than the preset minimum value, it indicates that the contribution of each measurement point to the differentiation of the confidence value of the same source is not obvious. At this time, the measurement point contribution value corresponding to each effective measurement point can be set to the same value, or the event wavefront combination can be marked as the measurement point contribution is indistinguishable, and the admission priority of the event wavefront combination can be reduced in the subsequent dynamic admission control.

[0116] For example, when the second, third, fourth, and fifth measuring points constitute an event wavefront combination, if the third and fourth measuring points are located on both sides of the fault location interval, their arrival time difference is highly consistent with the theoretical propagation time difference, and their polarity relationship can accurately reflect the characteristics of the fault traveling wave propagating to both sides, then the measuring point contribution values ​​corresponding to the third and fourth measuring points are relatively high. If the second measuring point is affected by noise, resulting in a lower energy change rate, but the arrival time still conforms to the propagation law, then the second measuring point can still retain a lower but effective measuring point contribution value. Thus, the co-origin confidence value can reflect both the degree of co-origin of the overall wavefront combination and the actual support strength of each measuring point for the judgment result.

[0117] Step 5: Based on the co-origin confidence value and measurement point contribution value group corresponding to the event wavefront combination, perform dynamic access control on the measurement points, candidate fault traveling wave events, and event wavefront combinations participating in dynamic wave velocity calculation to obtain the dynamic access control results; determine whether the dynamic wave velocity calculation conditions are met based on the dynamic access control results, and perform fault location processing based on the judgment results.

[0118] In one specific implementation, for each candidate fault traveling wave event and its corresponding event wavehead combination in the candidate fault traveling wave event set, the homology confidence value and measurement point contribution value group corresponding to the event wavehead combination are read. Based on the homology confidence value, whether the contribution values ​​of each measurement point are balanced, whether the residual of the arrival time of the measurement point meets the preset time consistency criterion, and whether the polarity of the traveling wave wavehead conforms to the propagation relationship on both sides of the fault interval, dynamic admission control is performed on the measurement points, candidate fault traveling wave events, and event wavehead combinations participating in dynamic wave velocity calculation. When the contribution value of a certain measurement point is lower than the preset contribution lower limit and its arrival time deviates significantly from the theoretical propagation relationship, the measurement point is removed or reduced in weight from the measurement points participating in dynamic wave velocity calculation. When the homology confidence value of a certain event wavehead combination is higher than the preset homology confidence threshold and at least includes effective measurement points on both sides of the fault interval, the event wavehead combination is determined as an admission object. Thus, the dynamic admission control result including admission candidate fault traveling wave events, admission event wavehead combinations, admission measurement points, and their weights is obtained.

[0119] Dynamic access control includes event access, measurement point access, and event wavefront combination access. For any event wavefront combination, when its homology confidence value... Root mean square of arrival time residuals Maximum contribution of measuring points When the timing status value meets the preset conditions, it is determined as the admission event wavefront combination. The root mean square of the arrival time residual. Calculate as follows:

[0120]

[0121] Maximum contribution of measuring points Calculate as follows:

[0122]

[0123] The admission event wavehead combination must at least meet the following conditions:

[0124]

[0125]

[0126]

[0127]

[0128] in, To preset the same-source credibility threshold, To preset the residual threshold at arrival time, To preset the threshold for excessive dominance of a single measurement point, A preset timing status threshold is set. In one embodiment, 0.70 is acceptable. Desirable , 0.75 is acceptable. It can be set to 0.80, or adjusted according to line length, sampling frequency, timing accuracy, and historical fault samples.

[0129] For any measurement point in the event wavefront combination ,like and If so, then the measuring point will be removed from the measuring points participating in the dynamic wave velocity calculation; if and If the measurement point is not found, then retain the measurement point but reduce its weight. Admission weight Calculate as follows:

[0130]

[0131] in, The lower limit of the contribution of the preset measurement points, To prevent extremely small positive numbers with a denominator of zero.

[0132] In the first fault side of the fault section, the nearest adjacent measuring point to the fault section and the next adjacent measuring point extending outwards are respectively denoted as... and The mileage positions of the two on the route are respectively and The arrival times of the corresponding candidate traveling wavefronts in the target event wavefront combination are respectively and .when At that time, the dynamic traveling wave velocity on the first fault side Calculate as follows:

[0133]

[0134] In the second fault side of the fault section, the nearest adjacent measuring point to the fault section and the next adjacent measuring point extending outward are respectively denoted as... and The mileage positions of the two on the route are respectively and The arrival times of the corresponding candidate traveling wavefronts in the target event wavefront combination are respectively and .when At that time, the dynamic traveling wave velocity on the second fault side Calculate as follows:

[0135]

[0136] First fault side dynamic traveling wave velocity weight Second fault side dynamic traveling wave velocity weight Calculate them as follows:

[0137]

[0138]

[0139] When both the first fault side and the second fault side meet the dynamic traveling wave velocity calculation conditions, the dynamic traveling wave velocity near the fault... Calculate as follows:

[0140]

[0141] When only the first fault side meets the dynamic traveling wave velocity calculation conditions, As the dynamic traveling wave velocity near the fault When only the second fault side meets the dynamic traveling wave velocity calculation conditions, then... As the dynamic traveling wave velocity near the fault And in the dynamic access control results, it is recorded that the dynamic traveling wave velocity calculation conditions on the other fault side are not met.

[0142] The two measuring points at the two ends of the faulty section are denoted as measuring point A and measuring point B, respectively, and their mileage positions on the line are respectively... and ,and Length of the fault zone Calculate as follows:

[0143]

[0144] The arrival times of the candidate traveling wavefronts corresponding to measurement points A and B in the target event wavefront combination are respectively and The distance from the fault point to measuring point A. Calculate as follows:

[0145]

[0146] The location of the fault on the transmission line Calculate as follows:

[0147]

[0148] when At that time, the location of the output fault point on the transmission line As a result of precise fault location; when or If the target event wavefront combination is determined to be inconsistent with the fault location interval, the output of the precise fault location result is cancelled, and the fault location interval location result and non-homogeneous wavefront anomaly mark are output.

[0149] The dynamic wave velocity calculation conditions are determined based on the results of dynamic access control. These conditions may include: the number of access measurement points is not less than a preset number; there are effective measurement points on both sides of the fault location interval; the homogeneity confidence value of the target event wavefront combination meets the preset requirements; there is no single measurement point that excessively dominates the target measurement point contribution value group; and the residual of arrival time across measurement points is within the allowable range. If the above conditions are met, the candidate fault traveling wave event with the highest homogeneity confidence value and the most stable distribution of measurement point contribution value group is selected from the access objects as the target fault traveling wave event. The corresponding event wavefront combination is determined as the target event wavefront combination, and the target homogeneity confidence value, the target measurement point contribution value group, and the set of measurement points for dynamic wave velocity calculation are determined simultaneously.

[0150] Under the condition of satisfying the dynamic wave velocity calculation, the dynamic traveling wave velocity near the fault is calculated based on the mileage difference between adjacent and next-next-adjacent measuring points on the same side in the dynamic wave velocity calculation measuring point set and the arrival time difference of the corresponding candidate traveling wave waveheads in the target event wavehead combination. Combined with the mileage positions of the measuring points at both ends of the fault section, the arrival time difference between the two ends, and the dynamic traveling wave velocity, the location of the fault point on the transmission line is determined, and the accurate fault location result is output. For example, if the fault section is located between the third and fourth measuring points, and the second, third, fourth, and fifth measuring points are all included, and the third and fourth measuring points... When the contribution value of the measuring point is the highest, the propagation time difference between the second and third measuring points and between the fourth and fifth measuring points can be used to correct the dynamic traveling wave velocity near the fault. Then, the distance between the fault point and the third measuring point can be inferred from the arrival time difference between the third and fourth measuring points. If the dynamic wave velocity calculation conditions are not met, such as the low confidence value of the same source of the target event wavefront combination, insufficient effective measuring points on both sides, or multiple candidate traveling wavefronts having non-same source overlap, the precise location of the fault point will not be forcibly calculated. Instead, the location result of the fault interval and the abnormal identification of non-same source wavefronts will be output to avoid mislocation caused by the initial traveling wave of different faults.

[0151] Example 2: Refer to Figure 4A distributed transmission line fault precise location system, comprising:

[0152] The data acquisition module provides the fundamental data source for accurate fault location in distributed transmission lines. By acquiring measurement point information from multiple distributed ranging terminals deployed along the transmission line, line topology information, and fault traveling wave data with time stamps and measurement point markers, this module can clarify the location relationships of the measurement points of each distributed ranging terminal, the line connection relationships, and the arrival status of the fault traveling wave at different measurement points. The data acquired by this module provides a unified data foundation for determining the fault location interval, establishing the initial measurement point set, extracting candidate traveling wavefronts, and subsequent fault location processing.

[0153] The wavefront extraction module identifies candidate traveling wave fronts from fault traveling wave data that can be used for subsequent analysis. This module determines the fault location interval based on the fault traveling wave data, measurement point information, and line topology information. It then determines an initial set of measurement points by combining the first and second fault sides of the fault interval, thus establishing a correspondence between the measurement points involved in subsequent calculations and the fault interval. Furthermore, this module extracts multiple candidate traveling wave fronts within a preset observation time window, assigning each candidate wavefront a corresponding arrival time and wavefront polarity. This provides the foundation for calculating multiple discharge density values, generating candidate fault traveling wave event sets, and forming event wavefront combinations.

[0154] The event generation module identifies potential fault traveling wave events within a preset observation time window based on multiple candidate traveling wave fronts. This module calculates multiple discharge density values ​​based on multiple candidate traveling wave fronts corresponding to each measuring point in the initial measuring point set. This reflects the density of candidate traveling wave fronts within the preset observation time window and the potential multiple discharge characteristics in the fault traveling wave data. Generating a set of candidate fault traveling wave events using multiple discharge density values ​​allows for the organization of fault traveling wave data according to these events, avoiding the influence of non-homogeneous wave fronts or multiple discharges when directly locating faults using a single candidate traveling wave front.

[0155] The combined calculation module establishes the correspondence between candidate fault traveling wave events and candidate traveling wave fronts at different measurement points, and evaluates the reliability of event front combinations. Based on the set of candidate fault traveling wave events and the multiple candidate traveling wave fronts corresponding to each measurement point in the initial measurement point set, this module forms event front combinations corresponding to the candidate fault traveling wave events, enabling the correlation analysis of candidate traveling wave fronts under the same candidate fault traveling wave event. Furthermore, this module calculates a homology confidence value and a measurement point contribution value set. The homology confidence value characterizes the reliability that the event front combination belongs to the same initial traveling wave of the same fault, the same propagation path, the same propagation mode, and the same time reference within the same candidate fault traveling wave event. The measurement point contribution value set reflects the measurement point contribution value corresponding to each measurement point in the event front combination.

[0156] The fault location processing module dynamically controls the fault location process based on the same-source confidence value and the measurement point contribution value group, and outputs the fault location processing results. This module dynamically adjusts the admission criteria for measurement points, candidate fault traveling wave events, and event wavefront combinations participating in dynamic wave velocity calculation, thereby selecting suitable objects for dynamic wave velocity calculation. The module determines whether the dynamic wave velocity calculation conditions are met and performs fault location processing based on the determination result. When the dynamic wave velocity calculation conditions are met, it can be used to calculate the dynamic traveling wave velocity near the fault and the location of the fault point on the transmission line. When the dynamic wave velocity calculation conditions are not met, it can be used to output the fault location results for the affected section and anomaly indicators for non-same-source wavefronts.

[0157] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for precise fault location in distributed transmission lines, characterized in that, include: Step 1: Obtain the measurement point information, line topology information, and fault traveling wave data with time stamps and measurement point marks corresponding to multiple distributed ranging terminals deployed along the transmission line; Step 2: Based on the fault traveling wave data, measurement point information and line topology information, determine the fault section. Based on the first and second fault sides of the fault section, determine the initial measurement point set from the measurement points corresponding to multiple distributed ranging terminals. Within the preset observation time window, extract multiple candidate traveling wave fronts with corresponding arrival times and traveling wave front polarities from the fault traveling wave data corresponding to each measurement point in the initial measurement point set. Step 3: Calculate multiple discharge density values ​​based on the multiple candidate traveling wave fronts corresponding to each measuring point in the initial measuring point set, and then generate a set of candidate fault traveling wave events. The calculation of the multiple discharge density value includes: calculating the multiple discharge density value based on the number of candidate traveling wavefronts at each measuring point in the initial measuring point set, the time interval between adjacent candidate traveling wavefronts, the energy change rate of the traveling wavefronts, the aggregation degree of traveling wavefronts across measuring points, and the order perturbation degree of the traveling wavefronts. Step 4: Based on the candidate fault traveling wave event set and the multiple candidate traveling wave waveheads corresponding to each measuring point in the initial measuring point set, form an event wavehead combination corresponding to the candidate fault traveling wave event, and calculate the homogeneity confidence value and measuring point contribution value group corresponding to the event wavehead combination. The co-origin confidence value is used to characterize the confidence level of event wavefront combinations belonging to the same candidate fault traveling wave event, the same fault initial traveling wave, the same propagation path, the same propagation mode, and the same time reference. The measurement point contribution value group includes the measurement point contribution value corresponding to each measurement point in the event wavefront combination. The measurement point contribution value is used to characterize the degree of contribution of the corresponding measurement point to the co-origin confidence value. Step 5: Based on the co-origin confidence value and measurement point contribution value group corresponding to the event wavefront combination, perform dynamic access control on the measurement points, candidate fault traveling wave events and event wavefront combinations participating in dynamic wave velocity calculation, and obtain the dynamic access control results. Based on the results of dynamic access control, determine whether the dynamic wave velocity calculation conditions are met, and perform fault location processing based on the judgment results.

2. The method for accurate fault location in distributed transmission lines according to claim 1, characterized in that, In step two, determining the initial set of measurement points includes: determining the fault location interval based on the arrival time of the traveling wave front, the polarity of the traveling wave front, the measurement point information, and the line topology information in the fault traveling wave data; selecting adjacent measurement points and the next adjacent measurement points on the first fault side and the second fault side of the fault location interval, respectively, to form the initial set of measurement points.

3. The method for accurate fault location in distributed transmission lines according to claim 1, characterized in that, In step two, extracting multiple candidate traveling wave fronts includes: performing denoising, bandpass filtering, and wavelet modulus maxima detection on the fault traveling wave data corresponding to each measurement point in the initial measurement point set to obtain abrupt change points; and determining abrupt change points whose amplitude, energy change rate, and duration meet the preset wave front criteria as candidate traveling wave fronts.

4. The method for accurate fault location in distributed transmission lines according to claim 3, characterized in that, In step three, generating a candidate fault traveling wave event set includes: comparing multiple discharge density values ​​with a first preset density threshold and a second preset density threshold respectively; when the multiple discharge density values ​​are less than the first preset density threshold, dividing the fault traveling wave data within a preset observation time window into a single fault traveling wave event, and writing the single fault traveling wave event into the candidate fault traveling wave event set; when the multiple discharge density values ​​are not less than the second preset density threshold, splitting the fault traveling wave data within a preset observation time window into multiple fault traveling wave sub-events, and writing the multiple fault traveling wave sub-events into the candidate fault traveling wave event set.

5. The method for accurate fault location in distributed transmission lines according to claim 4, characterized in that, In step three, generating the candidate fault traveling wave event set also includes: when the multiple discharge density values ​​are not less than the first preset density threshold and less than the second preset density threshold, increasing the number of candidate traveling wave fronts participating in matching for each measuring point in the initial measuring point set, and generating multiple enhanced candidate fault traveling wave events based on different candidate traveling wave front matching sequences, and writing the multiple enhanced candidate fault traveling wave events into the candidate fault traveling wave event set.

6. The method for accurate fault location in distributed transmission lines according to claim 4, characterized in that, In step four, forming the event wavefront combination includes: for each candidate fault traveling wave event in the candidate fault traveling wave event set, selecting the candidate traveling wave wavefront belonging to that candidate fault traveling wave event from each measuring point in the initial measuring point set to form the event wavefront combination.

7. The method for accurate fault location in distributed transmission lines according to claim 6, characterized in that, Step five involves fault location processing based on the judgment results, including: if the dynamic wave velocity calculation conditions are met, determining the target fault traveling wave event, the target event wavefront combination, the target homogeneity confidence value, the target measurement point contribution value group, and the dynamic wave velocity calculation measurement point set; then calculating the dynamic traveling wave velocity near the fault and the location of the fault point on the transmission line, and outputting the accurate fault location result; if the dynamic wave velocity calculation conditions are not met, outputting the fault location result of the interval and the non-homogeneous wavefront anomaly indicator.

8. A distributed transmission line fault precise location system, applied to the distributed transmission line fault precise location method according to any one of claims 1-7, characterized in that, include: The data acquisition module is used to acquire measurement point information, line topology information, and fault traveling wave data with time stamps and measurement point marks corresponding to multiple distributed ranging terminals deployed along the transmission line. The wavefront extraction module is used to determine the fault section based on fault traveling wave data, measurement point information and line topology information, determine the initial set of measurement points based on the first fault side and the second fault side of the fault section, and extract multiple candidate traveling wavefronts within a preset observation time window. The event generation module is used to calculate multiple discharge density values ​​based on multiple candidate traveling wave fronts corresponding to each measuring point in the initial measuring point set, and then generate a set of candidate fault traveling wave events. The combined calculation module is used to form a combination of event wavefronts corresponding to the candidate fault traveling wave events based on the candidate fault traveling wave event set and multiple candidate traveling wave wavefronts corresponding to each measuring point in the initial measuring point set, and to calculate the homogeneity confidence value and the measuring point contribution value group. The location processing module is used to dynamically control the access of the measurement points, candidate fault traveling wave events, and event wavefront combinations participating in dynamic wave velocity calculation based on the same source confidence value and measurement point contribution value group, to determine whether the dynamic wave velocity calculation conditions are met, and to perform fault location processing.

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