High-voltage cable multi-source partial discharge single-end positioning method, device and equipment and storage medium

Abstract

The invention provides a high-voltage cable multi-source partial discharge single-end positioning method, device and equipment and a storage medium. The method comprises the following steps: acquiring a partial discharge mixed signal at a single-end measurement end of a to-be-evaluated cable; based on a multi-source partial discharge inversion model pre-constructed for the to-be-evaluated cable, performing inversion recovery on the partial discharge mixed signal to obtain a plurality of original partial discharge pulse signals for synthesizing the partial discharge mixed signal and corresponding absolute occurrence time; and on the basis of each original partial discharge pulse signal and the corresponding absolute occurrence time, determining the position of a partial discharge source emitting each original partial discharge pulse signal. Through the method disclosed by the invention, the single-end positioning precision and reliability under the multi-source partial discharge condition can be remarkably improved.

Description

Technical Field

[0001] This disclosure relates to the field of power equipment condition monitoring technology, and in particular to a method, apparatus, equipment and storage medium for single-end location of multi-source partial discharge in high-voltage cables. Background Technology

[0002] High-voltage cable partial discharge single-end location technology is mainly used for online monitoring and location of insulation defects in power cables. It achieves precise distance measurement of the fault point by detecting the high-frequency partial discharge signal at one end of the cable and calculating the signal propagation time difference. This technology has significant application value in long-distance cable maintenance due to its flexible deployment and low cost.

[0003] However, traditional single-end positioning methods have significant limitations in practical applications. These methods heavily rely on accurate pulse propagation speed and clear pulse waveform identification. However, in real cable structures, signal dispersion and attenuation effects cause waveform distortion and increased uncertainty in propagation speed during pulse propagation. Especially when multiple partial discharge sources coexist, the superposition and interference of multiple partial discharge pulses make it difficult for traditional positioning methods to accurately identify the first arriving pulse and its precise arrival time from complex waveforms, leading to a significant decrease in positioning accuracy or even positioning failure. Therefore, how to effectively improve the accuracy and reliability of single-end positioning of multi-source partial discharges in high-voltage cables has become a key technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, this disclosure proposes a method, apparatus, equipment and storage medium for single-end positioning of multi-source partial discharge in high-voltage cables, which can effectively improve the accuracy and reliability of single-end positioning of multi-source partial discharge in high-voltage cables.

[0005] According to a first aspect of this disclosure, a method for single-end localization of multi-source partial discharge in high-voltage cables is provided, comprising: Acquire mixed partial discharge signals at a single-end measurement point of the cable to be evaluated; Based on the multi-source partial discharge inversion model pre-constructed for the cable to be evaluated, the partial discharge mixed signal is inverted and recovered to obtain multiple original partial discharge pulse signals and their corresponding absolute occurrence times for synthesizing the partial discharge mixed signal; Based on each of the original partial discharge pulse signals and their corresponding absolute occurrence times, the location of the partial discharge source that emitted each of the original partial discharge pulse signals is determined.

[0006] In one possible implementation, constructing the multi-source partial discharge inversion model includes: A calibration pulse signal is injected from one end of the cable to be evaluated, and the response signal after transmission through the cable to be evaluated is actually measured at the other end of the cable to be evaluated. Based on the calibration pulse signal and the response signal, a target transfer function reflecting the actual transmission performance of the cable to be evaluated is constructed. Based on the target transfer function, the multi-source partial discharge inversion model is constructed.

[0007] In one possible implementation, constructing a target transfer function reflecting the actual transmission performance of the cable to be evaluated based on the calibration pulse signal and the response signal includes: Perform Fast Fourier Transform on the calibration pulse signal and the response signal respectively to obtain the frequency domain representation of the calibration pulse signal and the frequency domain representation of the response signal; Based on the frequency domain representation of the calibration pulse signal and the frequency domain representation of the response signal, the amplitude response and phase response of the cable to be evaluated are calculated; Based on the amplitude and phase responses of the cable to be evaluated, a target transfer function reflecting the actual transmission performance of the cable to be evaluated is constructed.

[0008] In one possible implementation, after constructing a target transfer function reflecting the actual transmission performance of the cable under evaluation based on its amplitude and phase responses, the method further includes: Obtain the operating temperature of the cable to be evaluated; Temperature compensation is performed on the target transfer function based on the operating temperature.

[0009] In one possible implementation, constructing the multi-source partial discharge inversion model based on the target transfer function includes: The inverse Fourier transform of the target transfer function is performed to obtain the impulse response of the cable to be evaluated. Based on the impulse response, a partial discharge mixed signal prediction model is constructed for the cable to be evaluated; Based on the partial discharge mixed signal prediction model and the measured mixed signal, the multi-source partial discharge inversion model is constructed.

[0010] In one possible implementation, determining the location of the partial discharge source emitting each of the original partial discharge pulse signals based on each of the original partial discharge pulse signals and their corresponding absolute occurrence times includes: Extract the feature information of each of the original partial discharge pulse signals; Based on the characteristic information of each of the original partial discharge pulse signals, the feature vector of each of the original partial discharge pulse signals is calculated; Based on the feature vectors of each of the original partial discharge pulse signals, each of the original partial discharge pulses is clustered to obtain the target cluster; Based on the absolute occurrence time of each original partial discharge pulse signal in the target cluster, the location of the partial discharge source emitting each original partial discharge pulse signal is determined.

[0011] In one possible implementation, when clustering the original partial discharge pulses based on their feature vectors to obtain a target cluster, the following steps are included: DBSCAN clustering is performed on the feature vectors of each of the original partial discharge pulse signals to obtain initial clusters; Based on preset physical constraints, pseudo-sources and reflection sources in the initial cluster are removed, and homogeneous clusters are merged to obtain the target cluster.

[0012] According to a second aspect of this disclosure, a single-end positioning device for multi-source partial discharge of high-voltage cables is provided, comprising: The signal acquisition module is used to acquire the partial discharge mixed signal at the single-end measurement end of the cable to be evaluated; The inversion and recovery module is used to invert and recover the partial discharge mixed signal based on the multi-source partial discharge inversion model pre-constructed for the cable to be evaluated, so as to obtain multiple original partial discharge pulse signals and their corresponding absolute occurrence times for synthesizing the partial discharge mixed signal. The positioning module is used to determine the location of the partial discharge source that emitted each of the original partial discharge pulse signals based on each of the original partial discharge pulse signals and the corresponding absolute occurrence time.

[0013] According to a third aspect of this disclosure, a single-end locating device for multi-source partial discharge of high-voltage cables is provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to execute the method described in the first aspect of this disclosure.

[0014] According to a fourth aspect of this disclosure, a non-volatile computer-readable storage medium is provided that stores computer program instructions thereon, wherein the computer program instructions, when executed by a processor, implement the method described in the first aspect of this disclosure.

[0015] This disclosure provides a method, apparatus, device, and storage medium for single-end localization of multi-source partial discharge (SPD) in high-voltage cables. The method includes: acquiring a mixed SPD signal at a single-end measurement point of the cable to be evaluated; inverting and recovering the mixed SPD signal based on a pre-constructed multi-source SPD inversion model for the cable to be evaluated, obtaining multiple original SPD pulse signals and their corresponding absolute occurrence times to synthesize the mixed SPD signal; and determining the location of the SPD source emitting each original SPD pulse signal based on its absolute occurrence time. This disclosure, through a multi-source SPD inversion model constructed based on measured data of the cable to be evaluated, can effectively overcome the signal distortion problem caused by inherent dispersion and attenuation effects in cables. It mathematically and accurately inverts the mixed SPD signal, separates multiple superimposed undistorted original SPD pulses, and directly calculates the absolute occurrence time of each pulse. Based on the recovered undistorted original pulse signals and their absolute occurrence times, this method can significantly improve the accuracy and reliability of single-end localization in multi-source SPD situations.

[0016] Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this disclosure together with the specification and serve to explain the principles of this disclosure.

[0018] Figure 1 A flowchart illustrating a method for locating single-end multi-source partial discharge of a high-voltage cable according to an embodiment of the present disclosure is shown. Figure 2 A schematic block diagram of a high-voltage cable multi-source partial discharge single-end positioning device according to an embodiment of the present disclosure is shown. Figure 3 A schematic block diagram of a high-voltage cable multi-source partial discharge single-end positioning device according to an embodiment of the present disclosure is shown. Detailed Implementation

[0019] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0020] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0021] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0022] <Method Implementation> Figure 1 A flowchart illustrating a method for locating single-end multi-source partial discharge in a high-voltage cable according to an embodiment of the present disclosure is shown. Figure 1 As shown, the method includes steps S1100-S1300.

[0023] The S1100 acquires a mixed partial discharge signal at a single measurement end of the cable under evaluation. Specifically, during the operation of the cable under evaluation, a high-frequency current transformer is used to continuously monitor a single end of the cable to acquire the mixed partial discharge signal.

[0024] S1200, based on a pre-built multi-source partial discharge inversion model for the cable to be evaluated, performs inversion recovery on the partial discharge mixed signal to obtain multiple original partial discharge pulse signals and their corresponding absolute occurrence times for the synthesized partial discharge mixed signal.

[0025] It should be noted that before implementing the method of this disclosure, a multi-source partial discharge inversion model needs to be constructed for the cable to be evaluated and stored in the system executing the method of this disclosure. In this way, when performing this step, the multi-source partial discharge inversion model can be retrieved to invert and recover the partial discharge mixed signal, thereby obtaining multiple original partial discharge pulse signals of the synthesized partial discharge mixed signal and their corresponding absolute occurrence times.

[0026] In one possible implementation, the process of constructing a multi-source partial discharge inversion model for the cable to be evaluated may include the following steps: First, a calibration pulse signal is injected into one end of the cable to be evaluated, and the response signal after transmission through the cable is measured at the other end. Specifically, a known nanosecond-level calibration pulse with broadband characteristics is injected into the measurement end of the cable to be evaluated. x(t) Simultaneously record the response signal after transmission through the cable to be evaluated. y(t) .

[0027] Second, based on the calibration pulse signal and response signal, a target transfer function reflecting the actual transmission performance of the cable to be evaluated is constructed. This may specifically include the following steps: Step 1, respectively, for the calibration pulse signal x(t) and response signal y(t) Perform a Fast Fourier Transform to obtain the frequency domain representation of the calibration pulse signal. Frequency domain representation of the response signal .

[0028] Step 2, Frequency Domain Representation Based on Calibration Pulse Signal Frequency domain representation of the response signal Calculate the amplitude response of the cable to be evaluated. and phase response ∠ Among them, the amplitude response This phase response directly reflects the attenuation characteristics of the cable at different frequency components. ∠ It directly reflects the dispersion characteristics of the cable at different frequency components.

[0029] This amplitude response and phase response ∠ By representing the calibration pulse signal in the frequency domain Frequency domain representation of the response signal The results were obtained through comparative calculations. Specifically, the amplitude response... The calculation formula is as follows: Phase response ∠ The calculation formula is as follows: ∠ Step 3, based on the amplitude response of the cable to be evaluated and phase response ∠ Construct a target transfer function that reflects the actual transmission performance of the cable to be evaluated. The target transfer function is... The calculation formula is as follows: The above target transfer function It is built based on the measured data of the cable to be evaluated, so it automatically includes the comprehensive influence of actual factors such as the actual cable joints and aging degree of the cable to be evaluated on the transmission characteristics, which is more accurate than a simple theoretical transfer function model.

[0030] In one possible implementation, to address the issue of target transfer function drift with temperature, after constructing the target transfer function, a temperature compensation operation is performed on the target transfer function based on the actual operating temperature of the cable to be evaluated. The specific temperature compensation steps are as follows: Step 4: Obtain the operating temperature of the cable to be evaluated The operating temperature This refers to the cable temperature monitored in real time during multi-source partial discharge single-end positioning testing of the cable to be evaluated.

[0031] Step 5: Based on the operating temperature of the cable to be evaluated Transfer function to target Temperature compensation is performed to obtain the temperature-compensated target transfer function. .

[0032] In one possible implementation, the temperature compensation step is based on pre-built temperature compensation models for both amplitude response and phase response. Specifically, the amplitude response temperature compensation model is used to calculate the current operating temperature of the cable being evaluated. and operating frequency Calculate the amplitude response after temperature compensation. The temperature compensation model for this phase response is used to assess the current operating temperature of the cable being evaluated. and operating frequency Calculate the phase response after temperature compensation. Therefore, the amplitude response can be determined based on the temperature compensation. and phase response Construct the temperature-compensated target transfer function .

[0033] In one possible implementation, the following steps are included when constructing the temperature compensation models for the amplitude response and the phase response: First, under the experimental conditions, at different ambient temperatures Below: Repeated target transfer function The construction steps yield a series of transfer functions at different temperatures. .

[0034] Then, temperature compensation models for the amplitude response and the phase response are established based on the two core components (amplitude response and phase response) of the transfer function at different temperatures.

[0035] Specifically, the temperature compensation model for amplitude response: for each frequency point The amplitude response of the transfer function at each temperature is extracted, and a polynomial fitting method is used to establish the temperature... With amplitude response Functional relationship This yields the temperature compensation model for the amplitude response. In a specific example, this temperature compensation model for the amplitude response can be as follows: In the formula, ， ， The data was obtained by fitting the measured data at each temperature point.

[0036] Temperature compensation model for phase response: for each frequency point The phase response of the transfer function at each temperature is extracted, and a polynomial fitting method is used to establish the temperature... Phase response Functional relationship This refers to the temperature compensation model for the phase response. In a specific example, the temperature compensation model for the phase response can be shown below: In the formula, ， ， The data was obtained by fitting the measured data at each temperature point.

[0037] After constructing the temperature compensation models for the amplitude response and phase response, the models are stored in the system. During step 5, the temperature compensation models for the amplitude response and phase response will be directly read from the system; the operating temperature of the cable to be evaluated will be... and operating frequency Substituting the values ​​into the temperature compensation model for the amplitude response, the amplitude response at the current temperature is calculated. This achieves temperature compensation for the amplitude response; the operating temperature of the cable to be evaluated... and operating frequency Substitute the phase response into the temperature compensation model to calculate the phase response at the current temperature. This achieves temperature compensation for the phase response; finally, the amplitude response at the current temperature is used. and phase response By replacing the amplitude response and phase response in the target transfer function, the temperature-compensated target transfer function can be obtained. The temperature-compensated target transfer function is shown below: In this embodiment, the introduction of ambiguous intermediate parameters (such as wave velocity and attenuation coefficient) is avoided. Compensation is performed directly based on the measured, temperature-related amplitude and phase responses, making the physical meaning of the temperature compensation model clear, the compensation path direct, and the accuracy high.

[0038] Third, based on the target transfer function, a multi-source partial discharge inversion model is constructed. This may specifically include the following steps: Step 1: Perform an inverse Fourier transform on the target transfer function to obtain the impulse response of the cable to be evaluated. .

[0039] Step 2: Based on shock response A partial discharge mixed-signal prediction model for the cable to be evaluated is constructed. Specifically, it is assumed that... N If there are multiple partial discharge sources, the predicted value of the mixed partial discharge signal received at the measurement end can be expressed as: ,in In the formula, For the first i An unknown original partial discharge pulse signal, For each original partial discharge pulse signal The absolute moment of occurrence, The impulse response of the cable to be evaluated is obtained by performing an inverse Fourier transform on the target transfer function. According to N The predicted value of the mixed partial discharge signal synthesized from the original partial discharge pulse signals. The expression of this predicted value of the mixed partial discharge signal is the mixed partial discharge signal prediction model of the cable to be evaluated.

[0040] Step 3: Based on the mixed-signal prediction model and the measured mixed signal, construct a multi-source partial discharge inversion model. Specifically, transform the partial discharge localization problem into an optimization problem, the goal of which is to find an optimal set of... { } This makes the predicted value of the partial discharge mixed signal... Mixed partial discharge signal with actual acquisition of The difference is minimized. The objective function for this optimization problem is the L2 norm of the error. The objective function constructed is the multi-source partial discharge inversion model.

[0041] After constructing the multi-source partial discharge (PD) inversion model, the actual acquired PD mixed signal can be inverted and recovered based on the model to obtain multiple original PD pulse signals and their corresponding absolute occurrence times of the synthesized PD mixed signal. Specifically, a global optimization algorithm is used to iteratively adjust two sets of core optimization variables in the multi-source PD inversion model: 1. Original partial discharge pulse signals The absolute moment of occurrence ; 2. Describe each raw partial discharge pulse signal. Waveform parameter set for specific waveforms Specifically, by analyzing the original partial discharge pulse signal... Perform parametric modeling and represent it as In one specific implementation, the original partial discharge pulse signal is... A Gaussian pulse combination model is constructed, and the specific form of the Gaussian pulse combination model is shown below: In this modeling method, its waveform parameter set = ,in, Original partial discharge pulse signal amplitude, Original partial discharge pulse signal time offset, Original partial discharge pulse signal The pulse width.

[0042] By analyzing each original partial discharge pulse signal Parametric modeling is performed to transform the inversion problem into a problem involving finite-dimensional parameters { , The optimization problem of} is solved by minimizing the objective function J to simultaneously determine each original partial discharge pulse signal. and the corresponding absolute occurrence time .

[0043] S1300, based on each original partial discharge pulse signal and its corresponding absolute occurrence time, determines the location of the partial discharge source emitting each original partial discharge pulse signal. Specifically, this may include the following steps: First, extract the feature information of each raw partial discharge pulse signal. The feature information of each raw partial discharge pulse signal may include at least one of time-domain feature information, frequency-domain feature information, time-frequency-domain feature information, and statistical domain feature information. The time-domain feature information may include the pulse amplitude. A Ascent time descent time At least one of the following; the frequency domain feature information may include the center frequency. Spectral energy ,bandwidth At least one of the following; the time-frequency domain feature information may include wavelet coefficient entropy. Time-frequency clustering density At least one of the following; the statistical domain feature information may include skewness. kurtosis At least one of them.

[0044] Second, based on the characteristic information of each original partial discharge pulse signal, the feature vector of each original partial discharge pulse signal is calculated. Specifically, the following operations are performed for each original partial discharge pulse signal: Step 1: Concatenate the extracted feature information in a preset order to obtain the original feature vector, which is represented as follows: Step 2: Employing a weighted fusion strategy based on feature importance, independent weights are assigned to each specific feature information to obtain the final feature vector of the original partial discharge pulse signal. The representation of this final feature vector is shown below: It should be noted here that the weighting coefficient It is not fixed, but determined by feature importance analysis on different types of partial discharge source datasets, thereby assigning higher weights to features with stronger discriminative capabilities.

[0045] It should be further explained here that the selection of the original partial discharge pulse signal characteristic information and the allocation of the weights of each characteristic information were determined through systematic theoretical analysis and extensive experimental verification, as shown in the following process: 1. Physical Mechanism Analysis: Based on the multi-physical processes of partial discharge, four complementary feature information dimensions are selected: time domain, frequency domain, time-frequency domain, and statistical domain. Among them, time domain feature information captures temporal dynamics but is not sensitive to dispersion; frequency domain feature information reflects the spectral results but loses time information; time-frequency feature information takes into account both time and frequency characteristics, but is computationally complex; statistical domain feature information describes the distribution pattern but lacks instantaneous information.

[0046] 2. Feature validity verification: Through testing a large number of known types of partial discharge pulses, the set of feature information with the highest discriminative power and the strongest robustness is selected.

[0047] 3. Optimization of fusion weights: Network search and cross-validation methods are used to determine the optimal weight allocation of feature information in each dimension, ensuring that the fused feature vector has the best classification performance.

[0048] 4. Engineering Applicability Verification: The computational efficiency and reliability of this fusion mechanism are verified in actual cable testing scenarios, improving the accuracy of partial discharge source classification and demonstrating its technical superiority.

[0049] Third, based on the feature vectors of each original partial discharge pulse signal, the original partial discharge pulses are clustered to obtain the target cluster. Specifically, this may include the following steps: First, DBSCAN clustering is performed on the feature vectors of each original partial discharge pulse signal to obtain initial clusters. Specifically, the synchronously acquired power frequency voltage phase information is used to mark the power frequency phase angle of each recovered original partial discharge pulse signal, and the phase angle is incorporated into its corresponding feature vector through sine / cosine components to expand the feature vector for subsequent clustering calculations. Next, parameters are set according to the scaling characteristics of the feature vectors, with a neighborhood radius ε = 0.3-0.5 and a minimum number of points MinPts = 3-5. Then, density clustering is performed on the expanded feature vectors using DBSCAN clustering to obtain the initial clusters, while simultaneously identifying and removing noise point sets.

[0050] Then, based on preset physical constraints, spurious sources and reflection sources in the initial clusters are eliminated, and clusters with the same source are merged to obtain the target clusters. The preset physical constraints are formulated according to the physical laws of cable traveling waves and include at least one of the following: time sequence constraints, amplitude-distance attenuation constraints, waveform similarity constraints, power frequency phase consistency constraints, and time position constraints. The time sequence constraint requires that the true source pulse must appear earlier than its multiple reflected waves. The amplitude-distance attenuation constraint requires that the amplitude of the reflected wave must follow an exponential decay law. The waveform similarity constraint requires that if the original pulse signals of multiple clusters have highly similar waveforms, they are merged into a cluster with the same source. The power frequency phase consistency constraint requires that if the original pulse signals of multiple clusters have a consistent power frequency phase distribution, they are merged into a cluster with the same source. The time position constraint requires that the time positions of multiple reflected waves must be integer multiples of the position of the true source pulse.

[0051] In various specific embodiments, when removing spurious sources and reflection sources from the initial clusters and merging homogeneous clusters based on the above physical constraints to obtain the target clusters, the following steps may be included: False sources are eliminated based on amplitude-distance attenuation constraints. Specifically, the difference between the average amplitude of each cluster in the initial cluster and the theoretical amplitude predicted based on the inversion distance is calculated. Clusters that clearly violate the attenuation rule are marked as false sources and eliminated.

[0052] Identify reflection clusters based on time sequence constraints. Specifically, find cluster pairs that satisfy the following conditions: 1. Time relationship: ,in, The representative absolute occurrence time of the partial discharge source corresponding to a cluster in a cluster pair. 1. The representative absolute occurrence time of the partial discharge source corresponding to the other cluster in the cluster pair. 2. Sequence relationship: (The reflected wave time must be later than the actual source pulse time), and clusters with later times that meet the above conditions are identified as false reflection sources.

[0053] Clusters of similar sources are merged based on waveform similarity constraints and power frequency phase consistency constraints. Specifically, if multiple clusters of pulses have highly similar waveforms and consistent power frequency phase distributions, but may be separated in the characteristic space due to noise, they are merged into a single real partial discharge source.

[0054] In this embodiment, the density-based DBSCAN clustering algorithm is used as the basic clustering framework. This choice is based on the following technical considerations: 1. Adaptability to the number of unknown sources: The number of partial discharge sources in actual cables is unknown. DBSCAN does not require pre-specifying the number of clusters and can automatically discover naturally existing cluster structures in the data. 2. Natural removal of noise and spurious sources: The DBSCAN algorithm has a built-in noise identification mechanism that can automatically mark sparse points that do not meet the density requirements as noise. This is directly applicable to removing reflection spurious sources and measurement noise. 3. Capability to capture complex distributions: Different partial discharge sources may form non-spherical complex distributions in the feature space. DBSCAN can identify clusters of arbitrary shapes, avoiding the limitations of traditional spherical clustering algorithms. Of course, other clustering algorithms, such as K-Means, spectral clustering, or hierarchical clustering, can also be used, and the aforementioned physical constraints can be introduced for result verification and optimization.

[0055] It should be further noted that traditional clustering algorithms (such as those mentioned in IEEE Transactions) rely solely on mathematical features (such as amplitude and phase) for clustering, without utilizing prior knowledge of the physical world. In this embodiment, however, the physical laws governing cable waves are introduced as constraints during the clustering process. Under these strong physical constraints, the clustering algorithm can accurately classify the feature vectors of multiple reflections into their corresponding true source categories, thereby completely avoiding misclassification.

[0056] Fourth, based on the absolute occurrence time of each original partial discharge pulse signal in the target cluster, the location of the partial discharge source emitting each original partial discharge pulse signal is determined. Specifically, each target cluster represents an independent partial discharge source. This process is repeated for each target cluster, and for the first... i For the target cluster, calculate the i-th... i The absolute occurrence times of each original partial discharge pulse signal in each of the target clusters are determined, and the arithmetic mean of these absolute occurrence times is calculated as the nth occurrence time. i The first target cluster corresponding to the first i The absolute moment of occurrence of the source of the individual bureau. , represents the absolute moment of occurrence. The calculation formula is as follows: In the formula, For the first i The absolute moment when the source of the individual's release occurs. For the firsti In the nth target cluster j The absolute occurrence time of the original partial discharge pulse signal. k For the first i The number of original partial discharge pulse signals in each target cluster.

[0057] Using the principle of traveling wave propagation in cables, this represents the absolute moment of occurrence. Calculate the first i Distance from local discharge source to measurement end The calculation formula is: In the formula, For the first i The distance between the local discharge source and the measuring end. The wave velocity of the cable to be evaluated.

[0058] In one possible implementation, the wave velocity of the cable to be evaluated From the temperature-compensated target transfer function Obtained from [the source].

[0059] Principle: Wave speed of the cable Phase response The slope is directly related. At a specific frequency. Below, there is an approximate relationship: in, It is the phase constant, and Related, This is the cable reference length.

[0060] Engineering Implementation: To simplify calculations, the transfer functions at a series of different temperatures were obtained as described above. Then, the transfer function at different temperatures was studied. Phase analysis is performed to determine the phase constant at different temperatures. Based on the phase constant at different temperatures, the cable wave velocity at different temperatures is calculated using the aforementioned formula. Finally, a lookup table or fitting formula for "temperature-equivalent wave velocity" is established based on the cable wave velocity at different temperatures. Therefore, when performing positioning calculations, the location data is first obtained in real time. Then, through the constructed "temperature-equivalent wave velocity" lookup table or fitting formula... Calculate The corresponding temperature-compensated wave velocity; finally, substitute the temperature-compensated wave velocity into the distance. The calculation formula can accurately calculate the current temperature condition. i The distance between the local discharge source and the measuring end.

[0061] Once the traversal is complete, the distance to the measuring end of each partial discharge source can be obtained, enabling accurate single-end positioning of multiple partial discharge sources.

[0062] This disclosure provides a method for single-end localization of multi-source partial discharge (PSD) in high-voltage cables, comprising: acquiring a mixed PSD signal at a single-end measurement point of the cable to be evaluated; inverting and recovering the mixed PSD signal based on a pre-constructed multi-source PSD inversion model for the cable to be evaluated, obtaining multiple original PSD pulse signals and their corresponding absolute occurrence times of the synthesized mixed PSD signal; and determining the PSD source location emitting each original PSD pulse signal based on each original PSD pulse signal and its corresponding absolute occurrence time. This disclosure, through a multi-source PSD inversion model constructed based on measured data of the cable to be evaluated, can effectively overcome the signal distortion problem caused by the inherent dispersion and attenuation effects of the cable, mathematically accurately inverting the mixed PSD signal, separating multiple superimposed undistorted original PSD pulses, and directly calculating the absolute occurrence time of each pulse. Based on the recovered undistorted original pulse signals and their absolute occurrence times, the method of this disclosure can significantly improve the single-end localization accuracy and reliability in multi-source PSD situations.

[0063] Furthermore, the high-voltage cable multi-source partial discharge single-end positioning method provided in this disclosure has achieved technological breakthroughs in several key aspects through systematic technological innovation.

[0064] 1. Strong multi-source separation capability: By constructing a multi-source partial discharge inversion model, it is possible to effectively separate and locate dual-source partial discharge pulses that are completely overlapping in the time domain.

[0065] 2. High anti-distortion capability: At the end of a 100-meter cable, the positioning error of the partial discharge source is reduced by more than 70% compared with the traditional TDR method.

[0066] 3. High reliability: After introducing physical constraint clustering, the false source misjudgment rate is less than 5% under strong reflection interference environment.

[0067] 4. Good environmental adaptability: Through the temperature compensation mechanism, the positioning result drift is controlled within ±0.5 meters in the temperature range of -10°C to 50°C.

[0068] 5. Cost advantage: The single-end measurement mechanism eliminates the need to install expensive synchronous sampling devices at the other end of the cable or lay synchronous signal transmission channels, which can greatly reduce the cost and engineering complexity of partial discharge location.

[0069] <Device Embodiment> Figure 2 A schematic block diagram of a high-voltage cable multi-source partial discharge single-end positioning device according to an embodiment of the present disclosure is shown. Figure 2 As shown, the device 100 includes: Signal acquisition module 110 is used to acquire partial discharge mixed signals at a single-end measurement end of the cable to be evaluated; The inversion and recovery module 120 is used to invert and recover the partial discharge mixed signal based on the multi-source partial discharge inversion model pre-constructed for the cable to be evaluated, so as to obtain multiple original partial discharge pulse signals and their corresponding absolute occurrence times for synthesizing the partial discharge mixed signal. The positioning module 130 is used to determine the location of the partial discharge source that emitted each of the original partial discharge pulse signals based on each of the original partial discharge pulse signals and the corresponding absolute occurrence time.

[0070] <Equipment Example> Figure 3 A schematic block diagram of a high-voltage cable multi-source partial discharge single-end locating device according to an embodiment of the present disclosure is shown. Figure 3 As shown, the high-voltage cable multi-source partial discharge single-end positioning device 200 includes a processor 210 and a memory 220 for storing executable instructions of the processor 210. The processor 210 is configured to implement any of the aforementioned high-voltage cable multi-source partial discharge single-end positioning methods when executing the executable instructions.

[0071] It should be noted here that the number of processors 210 can be one or more. Furthermore, the high-voltage cable multi-source partial discharge single-end positioning device 200 of this embodiment may also include an input device 230 and an output device 240. The processors 210, memory 220, input device 230, and output device 240 can be connected via a bus or other means, which are not specifically limited here.

[0072] The memory 220, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and various modules, such as the program or module corresponding to the high-voltage cable multi-source partial discharge single-end positioning method of this embodiment. The processor 210 executes various functional applications and data processing of the high-voltage cable multi-source partial discharge single-end positioning device 200 by running the software program or module stored in the memory 220.

[0073] Input device 230 can be used to receive input digital numbers or signals. These signals may include key signals related to user settings and function control of the device / terminal / server. Output device 240 may include a display device such as a screen.

[0074] <Storage Medium Examples> According to a fourth aspect of this disclosure, a non-volatile computer-readable storage medium is also provided, on which computer program instructions are stored, which, when executed by processor 210, implement the single-end positioning method for multi-source partial discharge of high-voltage cables described above.

[0075] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for single-end positioning of multi-source partial discharge in high-voltage cables, characterized in that, include: Acquire mixed partial discharge signals at a single-end measurement point of the cable to be evaluated; Based on the multi-source partial discharge inversion model pre-constructed for the cable to be evaluated, the partial discharge mixed signal is inverted and recovered to obtain multiple original partial discharge pulse signals and their corresponding absolute occurrence times for synthesizing the partial discharge mixed signal; Based on each of the original partial discharge pulse signals and their corresponding absolute occurrence times, the location of the partial discharge source that emitted each of the original partial discharge pulse signals is determined.

2. The method according to claim 1, characterized in that, The construction of the multi-source partial discharge inversion model includes: A calibration pulse signal is injected from one end of the cable to be evaluated, and the response signal after transmission through the cable to be evaluated is actually measured at the other end of the cable to be evaluated. Based on the calibration pulse signal and the response signal, a target transfer function reflecting the actual transmission performance of the cable to be evaluated is constructed. Based on the target transfer function, the multi-source partial discharge inversion model is constructed.

3. The method according to claim 2, characterized in that, When constructing a target transfer function reflecting the actual transmission performance of the cable to be evaluated based on the calibration pulse signal and the response signal, the following steps are included: Perform Fast Fourier Transform on the calibration pulse signal and the response signal respectively to obtain the frequency domain representation of the calibration pulse signal and the frequency domain representation of the response signal; Based on the frequency domain representation of the calibration pulse signal and the frequency domain representation of the response signal, the amplitude response and phase response of the cable to be evaluated are calculated; Based on the amplitude and phase responses of the cable to be evaluated, a target transfer function reflecting the actual transmission performance of the cable to be evaluated is constructed.

4. The method according to claim 3, characterized in that, After constructing a target transfer function reflecting the actual transmission performance of the cable under evaluation based on its amplitude and phase responses, the method further includes: Obtain the operating temperature of the cable to be evaluated; Temperature compensation is performed on the target transfer function based on the operating temperature.

5. The method according to claim 2, characterized in that, When constructing the multi-source partial discharge inversion model based on the target transfer function, the following steps are included: The inverse Fourier transform of the target transfer function is performed to obtain the impulse response of the cable to be evaluated. Based on the impulse response, a partial discharge mixed signal prediction model is constructed for the cable to be evaluated; Based on the partial discharge mixed signal prediction model and the measured mixed signal, the multi-source partial discharge inversion model is constructed.

6. The method according to claim 1, characterized in that, Determining the location of the partial discharge source emitting each of the original partial discharge pulse signals based on each of the original partial discharge pulse signals and their corresponding absolute occurrence times includes: Extract the feature information of each of the original partial discharge pulse signals; Based on the characteristic information of each of the original partial discharge pulse signals, the feature vector of each of the original partial discharge pulse signals is calculated; Based on the feature vectors of each of the original partial discharge pulse signals, each of the original partial discharge pulses is clustered to obtain the target cluster; Based on the absolute occurrence time of each original partial discharge pulse signal in the target cluster, the location of the partial discharge source emitting each original partial discharge pulse signal is determined.

7. The method according to claim 6, characterized in that, When clustering the original partial discharge pulses based on their feature vectors to obtain a target cluster, the process includes: DBSCAN clustering is performed on the feature vectors of each of the original partial discharge pulse signals to obtain initial clusters; Based on preset physical constraints, pseudo-sources and reflection sources in the initial cluster are removed, and homogeneous clusters are merged to obtain the target cluster.

8. A single-end positioning device for multi-source partial discharge of high-voltage cables, characterized in that, include: The signal acquisition module is used to acquire the partial discharge mixed signal at the single-end measurement end of the cable to be evaluated; The inversion and recovery module is used to invert and recover the partial discharge mixed signal based on the multi-source partial discharge inversion model pre-constructed for the cable to be evaluated, so as to obtain multiple original partial discharge pulse signals and their corresponding absolute occurrence times for synthesizing the partial discharge mixed signal. The positioning module is used to determine the location of the partial discharge source that emitted each of the original partial discharge pulse signals based on each of the original partial discharge pulse signals and the corresponding absolute occurrence time.

9. A single-end positioning device for multi-source partial discharge of high-voltage cables, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to implement the method of any one of claims 1 to 7 when executing the executable instructions.

10. A non-volatile computer-readable storage medium storing computer program instructions thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the method described in any one of claims 1 to 7.

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