Traveling wave-based high-voltage cable fault positioning method

Abstract

The invention belongs to the technical field of high-voltage cable fault positioning, and particularly discloses a high-voltage cable fault positioning method based on traveling waves. According to the method, through the constructed cooperative iteration positioning mechanism of the electrical and vibration double-physical field, the space constraint generated by the vibration signal is deeply fused into the solution cycle of electrical positioning, the pseudo solution generated by mathematical calculation is effectively eliminated through the rigid constraint of the physical space, the uniqueness and high confidence of the output result are ensured, and the accuracy of the electrical positioning is improved. The inherent multi-solution fuzzy problem of the traditional traveling wave positioning method is fundamentally solved; through a dynamic model parameter adjustment mechanism, the traveling wave velocity and the vibration propagation model can be self-calibrated according to real-time data in an iterative solution process, dependence on fixed preset parameters is eliminated, systematic errors caused by model misalignment are reduced, and the precision of a positioning result and the adaptability to a field environment are improved.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage cable fault location technology, specifically relating to a high-voltage cable fault location method based on traveling waves. Background Technology

[0002] High-voltage cables, as the core arteries of modern urban power grids, are crucial to socio-economic development due to their safe and stable operation. When cables experience faults such as insulation breakdown, transient traveling wave signals are generated—electromagnetic waves that propagate at high speeds along the cable line. Fault location technology based on the traveling wave principle, by capturing and analyzing these transient signals, has become one of the key technical means for rapidly restoring power supply.

[0003] In existing technologies, cable fault location methods based on traveling waves mainly rely on traveling wave sensors deployed at both ends or multiple nodes of the cable. By accurately measuring the time difference between the arrival of the faulty traveling wave at different sensors and combining this with the known propagation speed of the traveling wave, the location of the fault point can be calculated using the time difference ranging principle. To improve reliability, some solutions also attempt to introduce other sensing technologies such as distributed optical fibers deployed along the cable to collect vibration or temperature signals generated at the fault point as auxiliary verification methods for the traveling wave location results.

[0004] However, the above-mentioned existing technologies have certain technical defects in practical applications: (1) In complex cable networks with branches, the location equation is solved based solely on the arrival time difference of traveling waves, which often results in multiple possible candidate locations in mathematics. That is, there is a problem of multi-valued solutions, and it is difficult to effectively distinguish them based solely on electrical quantities.

[0005] (2) The propagation speed of traveling waves in cables is not constant. It is affected by factors such as cable load, operating temperature and material aging. Using a fixed wave velocity value for calculation will introduce significant positioning errors. At the same time, the propagation characteristics of the vibration signal used for auxiliary verification are also affected by the complex cable laying environment, resulting in uncertainty in the independent verification results themselves. Summary of the Invention

[0006] In view of this, in order to solve the problems mentioned in the background technology, a high-voltage cable fault location method based on traveling waves is proposed.

[0007] The objective of this invention can be achieved through the following technical solution: This invention provides a high-voltage cable fault location method based on traveling waves, comprising: in response to a fault time trigger signal, simultaneously acquiring electrical traveling wave signals and distributed vibration sensing signals at multiple monitoring points of the high-voltage cable line.

[0008] Based on the electrical traveling wave signal, the initial arrival time of the traveling wave at each monitoring point is extracted, and a set of wavefront times is constructed.

[0009] Based on the distributed vibration sensing signals, the possible vibration area is determined.

[0010] Based on the preset topology of the high-voltage cable line and the initial traveling wave propagation speed under the current operating conditions, the electrical traveling wave signal is processed to generate an initial candidate fault location set containing multiple candidate fault locations.

[0011] Based on the possible vibration region and the initial candidate fault location set, a collaborative iterative process is performed to generate and output a uniquely determined final fault location.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention, through the construction of a collaborative iterative positioning mechanism of electrical and vibration dual physical fields, deeply integrates the spatial constraints of vibration signal generation into the solution loop of electrical positioning. Through the hard constraints of physical space, it effectively eliminates the false solutions generated by mathematical calculations, ensuring the uniqueness and high confidence of the output results, and fundamentally solves the inherent multi-solution ambiguity problem of traditional traveling wave positioning methods.

[0013] 2. This invention, through a dynamic model parameter adjustment mechanism, can self-calibrate the traveling wave velocity and vibration propagation model based on real-time data during the iterative solution process. This eliminates the dependence on fixed preset parameters, enabling the positioning results to truly reflect the actual working conditions and environmental characteristics of the cable at the moment of the fault occurrence. It reduces systematic errors caused by model inaccuracies and improves the accuracy of the positioning results and adaptability to the field environment.

[0014] 3. This invention transforms fault location from a one-time open-loop calculation into a closed-loop intelligent optimization process with inherent verification and self-consistency capabilities, enhancing reliability and robustness. Furthermore, the experience gained from each successful fault location will be used to optimize the initial model, enabling it to have self-learning and evolutionary capabilities, which is beneficial to the long-term operational stability and accuracy of the system. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart illustrating the implementation steps of the method of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1 As shown, the present invention provides a high-voltage cable fault location method based on traveling waves, the specific steps of which are as follows: in response to the fault time trigger signal, electrical traveling wave signals and distributed vibration sensing signals at multiple monitoring points of the high-voltage cable line are collected simultaneously.

[0019] Based on the electrical traveling wave signal, the initial arrival time of the traveling wave at each monitoring point is extracted, and a set of wavefront times is constructed.

[0020] In one feasible embodiment of the present invention, the specific construction process of the wavefront time set includes: filtering, denoising and normalizing the electrical traveling wave signals of the multiple monitoring points to obtain standardized traveling wave transient signals.

[0021] It should be noted that the specific operation of the filtering and noise reduction process can be as follows: apply a digital bandpass filter to the electrical traveling wave signal, the passband range of which is usually set between 100 kHz and 2 MHz, to filter out the low-frequency power frequency components and high-frequency random noise of the electrical traveling wave signal, and retain the energy of the steep part of the traveling wave front to the maximum extent.

[0022] The specific operation of the normalization process can be as follows: normalize the filtered and denoised electrical traveling wave signal, and scale its amplitude to the range of [-1, 1].

[0023] A waveform mutation detection algorithm is used to identify the first mutation point in each of the standardized traveling wave transient signals, and the timestamp of the first mutation point is recorded as the arrival time of the wavefront of the corresponding monitoring point.

[0024] In one specific example, the waveform abrupt change detection algorithm can be a continuous wavelet transform modulus maxima method. The specific identification process includes: decomposing the traveling wave transient signal into multiple scales using a mother wavelet function with time-frequency localization characteristics. The traveling wave front, as a transient abrupt change, will manifest its energy on the wavelet transform's time-frequency spectrum as a modulus maxima ridge with the largest amplitude, spanning multiple scales. Further searching along the time axis, when the first modulus maxima point matching this characteristic is detected, that point is determined to be the location of the first abrupt change point. The location of the traveling wave front is then determined.

[0025] The specific process of recording the timestamp of the first mutation point as the arrival time of the wavefront of the corresponding monitoring point includes: reading the index position of each identified first mutation point in the time series, and combining it with the collected sampling rate and synchronization clock information to convert it into a high-precision absolute time, usually requiring a precision of nanoseconds. This time is then marked as the arrival time of the wavefront of the corresponding monitoring point.

[0026] The arrival times of wavefronts at all monitoring points are summarized to form a set of wavefront times.

[0027] Based on the distributed vibration sensing signals, the possible vibration area is determined.

[0028] In one feasible embodiment of the present invention, the specific process of determining the possible vibration region includes: extracting the actual arrival time sequence of the vibration wave propagating to each optical fiber sensing point from the distributed vibration sensing signal.

[0029] It should be noted that the distributed vibration sensing signal is a two-dimensional data matrix, where the rows represent different locations on the optical fiber, the columns represent time, and the matrix element values ​​represent the vibration intensity at that spatiotemporal point.

[0030] The key temporal features of vibration events are extracted from the distributed vibration sensing signals. The two-dimensional data matrix is ​​traversed, and the starting point of the vibration signal is detected in the time series of each location point using energy mutation or short-time zero-crossing rate algorithm. The timestamp corresponding to the starting point constitutes the actual arrival time series of the vibration wave propagating to each fiber optic sensing point.

[0031] Based on a pre-defined basic model describing the vibration propagation law, the vibration source is inverted using the actual arrival time series to obtain the estimated location of the vibration source.

[0032] It should be noted that this step aims to find the source location that best explains the observed time series data, based on the fundamental physical laws governing the propagation of vibration waves in a medium.

[0033] The basic model simplifies by assuming that the vibration wave propagates along the cable and its surrounding medium at an equivalent velocity. Using a linear fitting or least squares algorithm, the actual arrival time series is analyzed in a position-time coordinate system. Since the vibration wave propagates from the fault point outwards, these time points will exhibit an approximate V-shaped curve distribution on the graph. The algorithm aims to find the vertex of this V-shaped curve, and its projection onto the position axis is the preliminary estimated location of the vibration source.

[0034] Based on the estimated location of the vibration source and its uncertainty range, a continuous cable segment space is delineated as the potential vibration area.

[0035] It should be noted that the initially estimated location of the vibration source is taken as the center point, and a certain distance is extended to both sides of the center point based on a preset confidence level or empirical value. The space of a continuous cable segment centered on the center point and with a total length twice the extended distance is defined as the potential vibration zone.

[0036] For example, for a directly buried cable, the initial estimated location of the vibration source is taken as the center point, and the distance extending on both sides of the center point can be set to 50 to 100 meters. Thus, the space of a continuous cable segment with the center point as the center and a total length twice the extension distance is defined as the vibration potential area.

[0037] Based on the preset topology of the high-voltage cable line and the initial traveling wave propagation speed under the current operating conditions, the electrical traveling wave signal is processed to generate an initial candidate fault location set containing multiple candidate fault locations.

[0038] In one feasible embodiment of the present invention, the specific process of generating an initial set of candidate fault locations containing multiple candidate fault locations includes: discretizing the preset topology into multiple candidate points, assuming each candidate point as a possible candidate fault location, and calculating the possible candidate fault locations. to the monitoring points respectively shortest path distance .

[0039] It should be noted that the discretization of the preset topology into multiple candidate points can specifically be achieved by uniformly discretizing the candidate points, and the discretization density is linked to the positioning accuracy.

[0040] For example, when the positioning accuracy requirement is ±0.5 meters, the discrete density is one candidate point every 0.5 meters; when the positioning accuracy requirement is ±1 meter, the discrete density is one candidate point every 1 meter.

[0041] Calculate candidate points Theoretical time difference between ,in This represents the propagation speed of the traveling wave under the current operating conditions.

[0042] Candidate point pairs are extracted from the wavefront time set. wave head arrival time Calculate the actual time difference .

[0043] If the theoretical time difference and the actual time difference satisfy... ,in To allow for error, possible candidate fault locations are identified. These can be used as candidate fault locations to obtain each candidate fault location, and are denoted as the initial set of candidate fault locations.

[0044] It should be noted that the allowable error is determined based on the synchronization accuracy of the monitoring point and the noise level of the traveling wave signal. The exemplary value range is 1ns to 10ns, and it can be adjusted according to the sampling rate of the monitoring system, such as 1GHz and above, and the synchronization clock accuracy, such as nanosecond level.

[0045] This invention constructs a collaborative iterative positioning mechanism based on electrical and vibration dual physical fields. It deeply integrates the spatial constraints of vibration signal generation into the solution loop of electrical positioning. Through the hard constraints of physical space, it effectively eliminates the spurious solutions generated by mathematical calculations, ensuring the uniqueness and high confidence of the output results. This fundamentally solves the inherent multi-solution ambiguity problem of traditional traveling wave positioning methods.

[0046] Based on the possible vibration region and the initial candidate fault location set, a collaborative iterative process is performed to generate and output a uniquely determined final fault location.

[0047] In one feasible embodiment of the present invention, the specific process of generating and outputting a uniquely determined final fault location includes: removing several candidate fault locations located outside the possible vibration area from the initial candidate fault location set to obtain a refined candidate location subset.

[0048] It should be noted that the refined subset of candidate locations is intended to filter out spurious solutions generated by purely mathematical calculations but which are physically unreasonable. The specific execution process includes the following: comparing the coordinates of each candidate fault location in the initial candidate fault location set with the start and end coordinates of the possible vibration area. If the geographical coordinates of a candidate fault location fall within the range of the possible vibration area, the candidate fault location is retained; otherwise, it is discarded.

[0049] Obtain the refined candidate position subset and a set of basic models describing the vibration propagation law in the current iteration round.

[0050] Based on the current basic model describing the vibration propagation law and the distributed vibration sensing signal, the possible vibration region is updated, and the updated possible vibration region is used to match the refined candidate position subset to form an updated refined candidate position subset.

[0051] It should be noted that the initial parameters of the basic model are determined according to the laying environment: the initial equivalent sound velocity for direct-buried cables is 1500-2000 m / s, for cable trench laying is 1800-2500 m / s, and for tunnel laying is 2000-3000 m / s. Subsequent optimization is achieved through iterative calibration.

[0052] It should also be noted that the cooperative iterative method is executed in an iterative loop. At the beginning of each iteration, the spatial constraints on the fault location are dynamically updated using the current optimal vibration physical model.

[0053] Specifically, the process first obtains a subset of refined candidate positions for the current iteration and a set of basic models describing the vibration propagation law. These basic models represent a mathematical description of the mechanical wave propagation characteristics of the medium in which the high-voltage cable is located, such as soil or a pipe. Key parameters may include the equivalent sound velocity and the attenuation coefficient.

[0054] Therefore, using the current basic model describing the vibration propagation law, combined with the original distributed vibration sensing signals, the vibration source localization algorithm is re-executed to calculate an updated possible vibration region. This step ensures that the spatial constraints of each iteration are based on the best current understanding of the physical environment. Subsequently, the refined subset of candidate locations is matched with this updated possible vibration region, retaining only those candidate points whose spatial locations still fall within the updated possible vibration region, forming a smaller or finely positioned updated refined subset of candidate locations.

[0055] For each candidate fault location in the updated refined candidate location subset, calculate an optimal fitted wave velocity value that best matches the theoretical traveling wave arrival time of that candidate fault location with the set of wavefront times.

[0056] Convergence is determined based on the physical rationality and central consistency of all optimal adaptive wave velocity values.

[0057] If the judgment result is convergence, the candidate fault location that has achieved convergence is determined as the final fault location; otherwise, the current basic model describing the vibration propagation law is adjusted and the next iteration is executed.

[0058] In one feasible embodiment of the present invention, the preset topology is specifically a geographic information database containing the route of high-voltage cable lines, branch nodes, and precise coordinates of monitoring points.

[0059] It should be noted that the geographic information database is constructed through GPS positioning, verification of as-built data, and on-site measurement. It can be defined that: the accuracy of monitoring point coordinates is ≤1 meter, the error of branch node position is ≤0.5 meters, and the error of cable routing is ≤2 meters, so as to ensure the accuracy of path length calculation.

[0060] In one feasible embodiment of the present invention, the specific calculation process of the most matching optimal adaptive wave velocity value includes: for a candidate fault location, calculating the theoretical path length of the traveling wave from the candidate fault location to each monitoring point according to the preset topology.

[0061] In one specific example, the calculation of the theoretical path length of the traveling wave from the candidate fault location to each monitoring point can be achieved through a path search algorithm, such as Dijkstra's algorithm, to calculate the shortest physical path length from the candidate fault location along the high-voltage cable conductor to each electrical traveling wave monitoring point. After completing this step, the system obtains a set of theoretical path lengths for the candidate location, i.e., the set of distances the traveling wave needs to propagate.

[0062] An error optimization function with wave speed as the variable is established. The error optimization function is used to quantify the overall error between the theoretical arrival time calculated from the wave speed and the theoretical path length and the set of wavefront times, such as the residual sum of squares.

[0063] It should be noted that the establishment of an error optimization function with wave speed as the variable aims to transform the physical problem of finding the optimal wave speed into a mathematical problem of minimizing time error. The specific implementation process includes: if an assumed wave speed is correct, then the time difference between each monitoring point calculated based on it and the theoretical path length should closely match the time difference between the measured wavefront arrival times. Therefore, the objective of the optimization function is to minimize the sum of squared residuals between the theoretical and measured arrival time differences for all monitoring point pairs. The mathematical expression of the minimized error objective function can be: ,in Candidate point pairs are extracted from the wavefront time set respectively. The arrival time of the wave head, From the candidate fault location to the monitoring points respectively The theoretical path length, The wave speed variable to be solved is... It represents the total number of candidate points.

[0064] Solving the error optimization function, the wave velocity solution that minimizes the overall error is taken as the best-fitting wave velocity value for the candidate fault location.

[0065] Specifically, the wave velocity solution that minimizes the overall error can be directly solved analytically. The process includes: taking the partial derivative of the objective function for minimizing the error with respect to the wave velocity variable, and setting this partial derivative to zero. By solving this equation, a unique analytical solution can be obtained, which is the wave velocity value that best matches the theoretical time with the measured time.

[0066] In one feasible embodiment of the present invention, the specific process of determining convergence based on the physical rationality and central consistency of all optimal adaptive wave velocity values ​​includes: if the number of candidate fault locations that simultaneously satisfy the two conditions characterizing physical rationality and central consistency of the optimal adaptive wave velocity is 1, then it indicates that there is a unique candidate fault location, and convergence is determined.

[0067] Conversely, if there is no single candidate fault location, it indicates that the convergence is not complete.

[0068] It should be noted that a comprehensive decision is made based on the results of the two layers of verification, counting the number of candidate fault locations that simultaneously meet both conditions. If the number is 1, meaning there is a unique candidate location whose optimal adaptive wave velocity value is both within the physically feasible range and highly consistent with the reference wave velocity under the current operating conditions, then the current iteration is considered to have successfully converged. At this point, this unique candidate fault location is confirmed as the final fault point, and the iteration loop terminates.

[0069] Conversely, if the number of candidate positions that meet the conditions is zero or more than one, it indicates that the current iteration has failed to eliminate all uncertainties or multiple solutions, and is therefore judged as non-converged, triggering the parameter adjustment mechanism and preparing to enter the next round of iteration.

[0070] The specific contents of the two conditions include: Condition 1, the optimal adaptive wave velocity value is within the theoretically feasible range describing the propagation speed of the traveling wave in the cable.

[0071] It should be noted that condition 1 is intended to perform a physical rationality check on the optimal adaptive wave velocity value corresponding to each candidate fault location.

[0072] The theoretically feasible range is a physical boundary calculated based on the dielectric constant of the cable insulation material. For example, for common cross-linked polyethylene insulated cables, this range is typically set between 1.6e8 and 1.8e8 meters per second. Any candidate position whose calculated optimal fit wave velocity falls outside this range is immediately excluded from the next round of evaluation because it violates the basic physical laws of electromagnetic wave propagation.

[0073] Condition 2: The deviation between the optimal matching wave velocity value and the operating condition reference wave velocity value estimated based on the current cable operating conditions is less than the deviation threshold characterizing the matching degree.

[0074] It should be noted that condition 2 is intended to perform a centralized consistency check on the optimal adaptive wave velocity value corresponding to each candidate fault location.

[0075] The reference wave velocity value for the operating condition is obtained by substituting real-time monitored cable load current and temperature data into a preset wave velocity-operating condition model. The deviation threshold characterizing the matching degree is typically set to 1% to 3%, representing an acceptable range of error between theory and reality.

[0076] In one feasible embodiment of the present invention, after outputting the uniquely determined final fault location, the following operation process is also included: recording the optimal adaptive wave velocity value corresponding to the convergence and the basic model describing the vibration propagation law at the current time, forming a set of empirical parameters for this location.

[0077] The empirical parameters are used to update the initial traveling wave velocity value and the initial values ​​of subsequent vibration model parameters to optimize the subsequent fault location process.

[0078] Specifically, after successfully outputting the final fault location, a self-learning and parameter evolution process is executed, aiming to solidify the successful experience of a single location into system knowledge and realize the long-term adaptive optimization of the location model for a specific line environment.

[0079] It should be noted that the trigger condition for this process is that the collaborative iterative processing module successfully converges and outputs a unique final fault location. Once triggered, two key parameters corresponding to this successful convergence are immediately recorded: the optimal adaptive wave velocity value corresponding to the candidate location that achieved convergence, and the basic model that ultimately describes the vibration propagation law during this iteration.

[0080] It should also be noted that the above process is not merely a simple numerical storage, but a process of dynamically updating the system's preset parameters. The recorded optimal adaptive wave velocity value is weighted and averaged with the preset initial traveling wave velocity value stored in the system. The weighting coefficient is usually set between 0.1 and 0.3 to ensure system stability and avoid excessive disturbance to the basic model caused by the results under a single special operating condition.

[0081] Similarly, the recorded basic model describing the current vibration propagation law will be used to update the initial model parameters used in the next coarse localization of the vibration source. In this way, after each successful localization, the understanding of the electrical and mechanical characteristics of the line is fine-tuned. As fault events accumulate, the preset initial parameters will become increasingly closer to the actual physical performance of the line under various typical operating conditions. This allows iterative calculations to begin from an initial point closer to the true value when a new fault occurs in the future, reducing the number of iterations required for convergence, improving the localization response speed, and enhancing long-term operational reliability.

[0082] This invention, through a dynamic model parameter adjustment mechanism, can self-calibrate the traveling wave velocity and vibration propagation model based on real-time data during the iterative solution process. This eliminates the dependence on fixed preset parameters, enabling the positioning results to truly reflect the actual working conditions and environmental characteristics of the cable at the moment of the fault occurrence. It reduces systematic errors caused by model inaccuracies and improves the accuracy of the positioning results and adaptability to the field environment.

[0083] In one feasible embodiment of the present invention, the specific process of adjusting the basic model describing the current vibration propagation law includes: when the judgment result is that the reason for non-convergence is that the optimal adaptive wave velocity values ​​corresponding to multiple candidate fault locations are all within the theoretically feasible range describing the cable traveling wave propagation speed, then the current operating condition information of the high-voltage cable line is obtained, and the operating condition reference wave velocity value is calculated based on the current operating condition information.

[0084] From the multiple candidate fault locations, the candidate fault location whose optimal adaptive wave velocity value is closest to the reference wave velocity value of the operating condition is selected as the reference fault location.

[0085] Based on the reference fault location, the set of wavefront times, and the distributed vibration sensing signal, at least one propagation medium parameter in the current basic model describing the vibration propagation law is calibrated in reverse.

[0086] Specifically, the feedback adjustment of the execution model parameters aims to use the optimal assumptions obtained from the electrical positioning side to correct the model parameters on the mechanical vibration side, thereby breaking the iterative deadlock. The most credible candidate fault location selected in the previous step is considered a known vibration source in the cable network topology. Based on this vibration source location, the physical distance from it to each distributed fiber optic sensing point along the line is calculated. Combining the actual arrival time series of the vibration wave extracted from the distributed vibration sensing signals, an optimization problem is solved to reverse-calculate the propagation medium parameters that best match this source-distance-time relationship.

[0087] For example, the equivalent sound velocity of the soil, the process specifically includes: (1) Input data preparation: obtaining the coordinates of the most reliable candidate location from the electrical positioning; obtaining the coordinates of each vibration sensor; reading the arrival time of the measured vibration wave from each sensor. ,in This refers to the number of each sensor.

[0088] (2) Distance calculation: Calculate the straight-line distance from the candidate location to each sensor: ,in For the coordinates of each vibration sensor, These are the coordinates of the candidate positions.

[0089] (3) Wave velocity calculation: Calculate the updated wave velocity according to the formula. .

[0090] (4) Model update: The updated wave velocity replaces the old wave velocity value in the vibration propagation model.

[0091] This invention transforms fault location from a one-time open-loop calculation into a closed-loop intelligent optimization process with inherent verification and self-consistency capabilities, enhancing reliability and robustness. Furthermore, the experience gained from each successful fault location will be used to optimize the initial model, enabling it to have self-learning and evolutionary capabilities, which is beneficial to the long-term operational stability and accuracy of the system.

[0092] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0093] Those skilled in the art will recognize that the algorithmic steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0094] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0095] 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.

[0096] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-voltage cable fault location method based on traveling waves, characterized in that: include: In response to the fault time trigger signal, electrical traveling wave signals and distributed vibration sensing signals are simultaneously acquired at multiple monitoring points along the high-voltage cable line. Based on the electrical traveling wave signal, the initial arrival time of the traveling wave at each monitoring point is extracted to construct a set of wavefront times; based on the distributed vibration sensing signal, the possible vibration area is determined. Based on the preset topology of the high-voltage cable line and the initial traveling wave propagation speed under the current operating conditions, the electrical traveling wave signal is processed to generate an initial candidate fault location set containing multiple candidate fault locations. Based on the possible vibration region and the initial candidate fault location set, a collaborative iterative process is performed to generate and output a uniquely determined final fault location.

2. The high-voltage cable fault location method based on traveling waves according to claim 1, characterized in that: The specific construction process of the wavefront time set includes: The electrical traveling wave signals from the multiple monitoring points are filtered, denoised, and normalized preprocessed to obtain standardized traveling wave transient signals. A waveform mutation detection algorithm is used to identify the first mutation point in each of the standardized traveling wave transient signals, and the timestamp of the first mutation point is recorded as the wavefront arrival time of the corresponding monitoring point. The arrival times of wavefronts at all monitoring points are summarized to form a set of wavefront times.

3. The high-voltage cable fault location method based on traveling waves according to claim 1, characterized in that: The specific process for determining the possible vibration region includes: Extract the actual arrival time sequence of the vibration wave propagating to each fiber optic sensing point from the distributed vibration sensing signal; Based on a pre-defined basic model describing the law of vibration propagation, the vibration source is inverted using the actual arrival time series to obtain the estimated location of the vibration source. Based on the estimated location of the vibration source and its uncertainty range, a continuous cable segment space is delineated as the potential vibration area.

4. The high-voltage cable fault location method based on traveling waves according to claim 1, characterized in that: The specific process of generating an initial set of candidate fault locations containing multiple candidate fault locations includes: The preset topology is discretized into multiple candidate points. Each candidate point is assumed to be a possible candidate fault location, and the possible candidate fault locations are calculated. to the monitoring points respectively shortest path distance ; Calculate candidate points Theoretical time difference between ,in This represents the propagation speed of the traveling wave under the current operating conditions. Candidate point pairs are extracted from the wavefront time set. wave head arrival time Calculate the actual time difference ; If the theoretical time difference and the actual time difference satisfy... ,in To allow for error, possible candidate fault locations are identified. These can be used as candidate fault locations to obtain each candidate fault location, and are denoted as the initial set of candidate fault locations.

5. The high-voltage cable fault location method based on traveling waves according to claim 3, characterized in that: The specific process of generating and outputting the unique final fault location includes: Several candidate fault locations located outside the possible vibration area in the initial candidate fault location set are removed to obtain a refined candidate location subset; Obtain the refined candidate position subset and a set of basic models describing the vibration propagation law in the current iteration round; Based on the current basic model describing the vibration propagation law and the distributed vibration sensing signal, the possible vibration region is updated, and the updated possible vibration region is used to match the refined candidate position subset to form an updated refined candidate position subset. For each candidate fault location in the updated refined candidate location subset, calculate an optimal fitted wave velocity value that best matches the theoretical traveling wave arrival time of that candidate fault location with the wavefront time set. Convergence is determined based on the physical rationality and central consistency of all optimal adaptive wave velocity values. If the judgment result is convergence, the candidate fault location that has achieved convergence is determined as the final fault location; otherwise, the current basic model describing the vibration propagation law is adjusted and the next iteration is executed.

6. The high-voltage cable fault location method based on traveling waves according to claim 5, characterized in that: The preset topology is specifically a geographic information database containing the route of high-voltage cable lines, branch nodes, and precise coordinates of monitoring points.

7. The high-voltage cable fault location method based on traveling waves according to claim 6, characterized in that: The specific calculation process for the optimal matching wave velocity value includes: For a candidate fault location, the theoretical path length of the traveling wave from the candidate fault location to each monitoring point is calculated based on the preset topology. An error optimization function with wave speed as the variable is established. The error optimization function is used to quantify the overall error between the theoretical arrival time calculated from the wave speed and the theoretical path length and the set of wavefront times. Solving the error optimization function, the wave velocity solution that minimizes the overall error is taken as the best-fitting wave velocity value for the candidate fault location.

8. The high-voltage cable fault location method based on traveling waves according to claim 5, characterized in that: The specific process for determining convergence based on the physical rationality and central consistency of all optimal adaptive wave velocity values ​​includes: If the number of candidate fault locations that simultaneously satisfy the two conditions characterizing physical rationality and central consistency for the optimal adaptive wave velocity is 1, then it indicates that there is a unique candidate fault location, and convergence is determined. Conversely, if there is no single candidate fault location, it indicates that the convergence is not complete. The specific contents of the two conditions include: Condition 1, the optimal adaptive wave velocity value is within the theoretically feasible range describing the propagation speed of the traveling wave in the cable; Condition 2: The deviation between the optimal matching wave velocity value and the operating condition reference wave velocity value estimated based on the current cable operating conditions is less than the deviation threshold characterizing the matching degree.

9. A high-voltage cable fault location method based on traveling waves according to claim 5, characterized in that: After outputting the uniquely determined final fault location, the following operation process is also included: Record the optimal adaptive wave velocity value corresponding to the convergence and the basic model describing the vibration propagation law, forming a set of empirical parameters for this positioning; The empirical parameters are used to update the initial traveling wave velocity value and the initial values ​​of subsequent vibration model parameters to optimize the subsequent fault location process.

10. A high-voltage cable fault location method based on traveling waves according to claim 8, characterized in that: The specific process of adjusting the current basic model describing the law of vibration propagation includes: When the judgment result is that the reason for non-convergence is that the optimal adaptive wave velocity values ​​corresponding to multiple candidate fault locations are all within the theoretically feasible range describing the propagation speed of the cable traveling wave, the current operating condition information of the high-voltage cable line is obtained, and the operating condition reference wave velocity value is calculated based on the current operating condition information. From the multiple candidate fault locations, the candidate fault location whose optimal adaptive wave velocity value is closest to the reference wave velocity value of the working condition is selected as the reference fault location. Based on the reference fault location, the set of wavefront times, and the distributed vibration sensing signal, at least one propagation medium parameter in the current basic model describing the vibration propagation law is calibrated in reverse.

Images