Method and apparatus for determining a discharge location of a power distribution cable

Abstract

The application discloses a power distribution cable discharge position determination method and device. The method comprises the following steps: obtaining a plurality of discharge pulse signals of a power distribution cable; determining a plurality of signal wave band sets corresponding to the plurality of discharge pulse signals respectively; determining signal polarities corresponding to the plurality of discharge pulse signals respectively according to the plurality of signal wave band sets corresponding to the plurality of discharge pulse signals respectively; and determining a target discharge position corresponding to the power distribution cable according to the signal polarities corresponding to the plurality of discharge pulse signals respectively. The application solves the technical problem that in the prior art, the position of partial discharge of a power distribution cable cannot be accurately determined under a complex operation environment, and thus effective monitoring and diagnosis of the partial discharge of the power distribution cable cannot be realized.

Description

Technical Field

[0001] This invention relates to the field of discharge detection, and more specifically, to a method and apparatus for determining the discharge location of a power distribution cable. Background Technology

[0002] In related technologies, the operating environment of power distribution cables is complex. The operation of surrounding power electronic devices and the discharge of nearby equipment can generate strong pulse current signals, which can interfere with the detection of partial discharges within the power distribution cable. Therefore, in complex operating environments, related technologies face the technical problem of being unable to accurately determine the location of partial discharges in power distribution cables, thus hindering effective monitoring and diagnosis of partial discharges.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This invention provides a method and apparatus for determining the discharge location of a power distribution cable, which at least solves the technical problem in related technologies that, under complex operating environments, it is impossible to accurately determine the location of partial discharge in a power distribution cable, thus making it impossible to effectively monitor and diagnose partial discharge in the power distribution cable.

[0005] According to one aspect of the present invention, a method for determining the discharge location of a power distribution cable is provided, comprising: acquiring a plurality of discharge pulse signals of the power distribution cable, wherein the plurality of discharge pulse signals include a pulse signal of the first end core wire of the power distribution cable, a pulse signal of the first end grounding wire of the power distribution cable, a pulse signal of the last end core wire of the power distribution cable, and a pulse signal of the last end grounding wire of the power distribution cable; determining a plurality of signal band sets corresponding to the plurality of discharge pulse signals respectively, wherein the corresponding plurality of signal band sets each include at least one signal band of the corresponding discharge pulse signal, and the corresponding plurality of signal band sets each correspond to different signal band categories; determining the signal polarity corresponding to the plurality of discharge pulse signals according to the plurality of signal band sets corresponding to the plurality of discharge pulse signals respectively, wherein the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value; and determining the target discharge location corresponding to the power distribution cable according to the signal polarity corresponding to the plurality of discharge pulse signals respectively.

[0006] Optionally, determining the signal polarity corresponding to each of the plurality of discharge pulse signals based on the plurality of signal band sets corresponding to each of the plurality of discharge pulse signals includes: determining the signal polarity corresponding to the target discharge pulse signal based on the target signal band set corresponding to any one of the plurality of discharge pulse signals in the following manner: when the target signal band set includes multiple signal bands, superimposing and averaging a predetermined number of signal bands in the plurality of signal bands to fit an array of multiple signal bands corresponding to the target discharge pulse signal; determining the peak value and peak value threshold corresponding to each of the array of multiple signal bands; determining the signal polarity corresponding to the target discharge pulse signal based on the peak value threshold and the peak value corresponding to each of the array of multiple signal bands; and obtaining the signal polarity corresponding to each of the other discharge pulse signals in the plurality of discharge pulse signals besides the target discharge pulse signal by using the same method as obtaining the signal polarity corresponding to the target discharge pulse signal.

[0007] Optionally, determining the signal polarity corresponding to the target discharge pulse signal based on the peak threshold and the peak values ​​corresponding to the plurality of signal band arrays includes: for any target signal band array in the plurality of signal band arrays, comparing the peak value of the corresponding target signal band with the peak threshold one by one according to the execution order of the plurality of target signal bands in the target signal band array to obtain a waveform comparison result corresponding to the corresponding target signal band, until the waveform comparison result is that the peak value of the corresponding target signal band is greater than or equal to the peak threshold, thus obtaining the first wave corresponding to the target signal band array; obtaining the first wave corresponding to the target signal band array by using the same method as obtaining the first wave corresponding to the target signal band array, and determining the signal polarity corresponding to the target discharge pulse signal based on the first waves corresponding to the plurality of signal band arrays.

[0008] Optionally, determining the set of multiple signal bands corresponding to the multiple discharge pulse signals includes: determining signal characteristic parameters corresponding to the multiple discharge pulse signals, wherein the signal characteristic parameters include equivalent duration, equivalent bandwidth, and signal amplitude ratio; and performing clustering operations on the multiple signal bands included in the multiple discharge pulse signals based on the signal characteristic parameters corresponding to the multiple discharge pulse signals to obtain the set of multiple signal bands corresponding to the multiple discharge pulse signals.

[0009] Optionally, the step of clustering the multiple signal bands included in the multiple discharge pulse signals according to the signal feature parameters corresponding to the multiple discharge pulse signals to obtain multiple signal band sets corresponding to the multiple discharge pulse signals includes: for any target discharge pulse signal among the multiple discharge pulse signals, determining the proximity index between any two signal bands among the multiple signal bands, wherein the proximity index represents the degree of proximity between any two signal bands; and determining the neighboring band set corresponding to each of the multiple signal bands according to the proximity index between any two signal bands among the multiple signal bands, wherein the corresponding neighboring band set includes at least one neighboring band, and the neighboring band is a band adjacent to the corresponding signal band. Other signal bands with a proximity index greater than the proximity threshold; based on the neighboring band sets corresponding to the multiple signal bands respectively, determine the mutually adjacent bands corresponding to the multiple signal bands respectively, wherein the mutually adjacent bands are signal bands that are adjacent to the corresponding signal bands; based on the mutually adjacent bands corresponding to the multiple signal bands respectively, determine the neighboring band distribution density corresponding to the multiple signal bands respectively; based on the neighboring band distribution density corresponding to the multiple signal bands respectively, determine the multiple signal band sets corresponding to the target discharge pulse signal; using the method of obtaining the multiple signal band sets corresponding to the target discharge pulse signal, obtain the multiple signal band sets corresponding to the other discharge pulse signals besides the target discharge pulse signal among the multiple discharge pulse signals respectively.

[0010] Optionally, determining the signal amplitude ratios corresponding to the plurality of discharge pulse signals respectively includes: determining a first amplitude ratio between the first-end core wire pulse signal and the last-end core wire pulse signal; determining a second amplitude ratio between the first-end ground wire pulse signal and the last-end ground wire pulse signal; determining a third amplitude ratio between the first-end core wire pulse signal and the first-end ground wire pulse signal; determining a fourth amplitude ratio between the last-end core wire pulse signal and the last-end ground wire pulse signal; and determining the signal amplitude ratios corresponding to the plurality of discharge pulse signals respectively based on the first amplitude ratio, the second amplitude ratio, the third amplitude ratio, and the fourth amplitude ratio.

[0011] Optionally, acquiring multiple discharge pulse signals of the power distribution cable includes: acquiring multiple initial pulse signals corresponding to the power distribution cable; determining multiple signal pairs from the multiple initial pulse signals; performing waveform matching on a first pulse signal and a second pulse signal included in any target signal pair among the multiple signal pairs to obtain a matching result corresponding to the target signal pair, wherein the target signal pair includes: the first pulse signal and the second pulse signal, the first pulse signal and the second pulse signal being acquired from different locations on the power distribution cable respectively; obtaining matching results corresponding to the target signal pair by using the method of obtaining matching results corresponding to the target signal pair; and determining the multiple discharge pulse signals from the multiple initial pulse signals based on the matching results corresponding to the multiple signal pairs respectively.

[0012] Optionally, the step of performing waveform matching on the first pulse signal and the second pulse signal included in any one of the plurality of signal pairs to obtain a matching result corresponding to the target signal pair includes: for any one of the plurality of first signal bands included in the first pulse signal, determining the band matching degree between the target first signal band and the plurality of second signal bands included in the second pulse signal, respectively, to obtain a plurality of band matching degrees corresponding to the target first signal band; obtaining a plurality of band matching degrees corresponding to the other first signal bands besides the target first signal band by using the method of obtaining the plurality of band matching degrees corresponding to the target first signal band; and obtaining a matching result corresponding to the target signal pair based on the plurality of band matching degrees corresponding to the plurality of first signal bands.

[0013] Optionally, determining the target discharge position corresponding to the power distribution cable based on the signal polarities corresponding to the plurality of discharge pulse signals includes: determining a first comparison result between the signal polarity of the first-end core wire pulse signal and the signal polarity of the last-end core wire pulse signal; determining an initial discharge position corresponding to the power distribution cable based on the first comparison result; determining a second comparison result between the signal polarity of the first-end grounding wire pulse signal and the signal polarity of the last-end grounding wire pulse signal; and verifying the initial discharge position based on the second comparison result to obtain the discharge position corresponding to the power distribution cable.

[0014] According to one aspect of the present invention, a device for determining the discharge location of a power distribution cable is provided, comprising: an acquisition module, configured to acquire a plurality of discharge pulse signals of the power distribution cable, wherein the plurality of discharge pulse signals include a pulse signal of the first end core wire of the power distribution cable, a pulse signal of the first end grounding wire of the power distribution cable, a pulse signal of the last end core wire of the power distribution cable, and a pulse signal of the last end grounding wire of the power distribution cable; a first determination module, configured to determine a plurality of signal band sets corresponding to the plurality of discharge pulse signals, wherein the corresponding plurality of signal band sets each include at least one signal band of the corresponding discharge pulse signal, and the corresponding plurality of signal band sets each correspond to different signal band categories; a second determination module, configured to determine the signal polarity corresponding to the plurality of discharge pulse signals based on the plurality of signal band sets corresponding to the plurality of discharge pulse signals, wherein the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value; and a third determination module, configured to determine a target discharge location corresponding to the power distribution cable based on the signal polarity corresponding to the plurality of discharge pulse signals.

[0015] In this embodiment of the invention, multiple discharge pulse signals of a power distribution cable are acquired, including pulse signals of the first-end core wire of the power distribution cable, pulse signals of the first-end grounding wire of the power distribution cable, pulse signals of the last-end core wire of the power distribution cable, and pulse signals of the last-end grounding wire of the power distribution cable. Multiple signal band sets corresponding to the multiple discharge pulse signals are determined, each of the corresponding signal band sets including at least one signal band of the corresponding discharge pulse signal, and each of the corresponding signal band sets corresponds to a different signal band category. Based on the multiple signal band sets corresponding to the multiple discharge pulse signals, the signal polarity corresponding to each of the multiple discharge pulse signals is determined, where the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value. Based on the signal polarity corresponding to each of the multiple discharge pulse signals, the target discharge position corresponding to the power distribution cable is determined. Multiple discharge pulse signals are acquired from the core wires and grounding wires at both ends of the power distribution cable. These signals are then classified into different signal band sets, enabling a more systematic analysis of signal characteristics. This allows for accurate determination of the signal polarity of each discharge pulse signal. Since the signal polarity changes during propagation due to the electrical characteristics of the power distribution cable, the discharge location, and the signal propagation path, the location of partial discharge in the power distribution cable can be accurately determined based on the signal polarities corresponding to the multiple discharge pulse signals. This solves the technical problem in related technologies where the location of partial discharge in power distribution cables cannot be accurately determined under complex operating environments, thus hindering effective monitoring and diagnosis of partial discharge in power distribution cables. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0017] Figure 1 This is a flowchart of a method for determining the discharge location of a power distribution cable according to an embodiment of the present invention;

[0018] Figure 2 This is a flowchart of the method for determining the discharge location of a power distribution cable in an optional embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of multi-terminal signal acquisition of a cable in an optional embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the acquisition module structure in an optional embodiment of the present invention;

[0021] Figure 5 This is an overall flowchart of the high-dimensional clustering separation method in an optional embodiment of the present invention;

[0022] Figure 6 This is a flowchart illustrating the calculation of the polarity of the first wave of the pulse signal in an optional embodiment of the present invention.

[0023] Figure 7 This is a structural block diagram of a power distribution cable discharge location determination device according to an embodiment of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] First, some nouns or terms that appear in the description of the embodiments of this application shall be interpreted as follows:

[0027] B-code: B-code (Binary Code) is a time encoding method that encodes time information into a signal using specific encoding rules.

[0028] DPC algorithm: The DPC algorithm is a density-based clustering algorithm.

[0029] KDE Algorithm: The KDE algorithm is a non-parametric density estimation method that estimates the probability density function of data points using a kernel function.

[0030] K-means algorithm: The K-means algorithm is a partition-based clustering algorithm.

[0031] DBSCAN Algorithm: The DBSCAN algorithm is a density-based clustering algorithm that achieves clustering by identifying the density connectivity of data points.

[0032] Example 1

[0033] According to an embodiment of the present invention, an embodiment of a method for determining the discharge location of a power distribution cable is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0034] Figure 1 This is a flowchart of a method for determining the discharge location of a power distribution cable according to an embodiment of the present invention, as follows: Figure 1 As shown, the method includes the following steps:

[0035] S102, acquire multiple discharge pulse signals of the power distribution cable, wherein the multiple discharge pulse signals include the pulse signal of the first core wire of the power distribution cable, the pulse signal of the first grounding wire of the power distribution cable, the pulse signal of the last core wire of the power distribution cable, and the pulse signal of the last grounding wire of the power distribution cable.

[0036] In step S102 of this application, multiple discharge pulse signals of the power distribution cable are acquired.

[0037] This involves multiple discharge pulse signals, which are pulse signals related to partial discharge collected from different locations of the power distribution cable (such as the core wires and grounding wires at the beginning and end).

[0038] This involves the first-end core wire pulse signal, which is a pulse signal related to partial discharge collected from the core wire (the main conductor part inside the cable used to transmit electrical energy) at the first end of the power distribution cable (i.e. the starting end of the cable).

[0039] This involves the grounding wire pulse signal at the beginning of the power distribution cable. This grounding wire pulse signal is a pulse signal related to partial discharge collected from the grounding wire (a conductor used for grounding protection to prevent dangerous situations such as leakage of electrical equipment) at the beginning of the power distribution cable.

[0040] This involves the end core wire pulse signal, which is a pulse signal related to partial discharge collected from the core wire at the end of the power distribution cable (i.e., the termination end of the cable).

[0041] This involves the end-grounding wire pulse signal, which is a pulse signal related to partial discharge collected from the grounding wire at the end of the power distribution cable.

[0042] By acquiring these pulse signals from different locations, the location and characteristics of partial discharge can be analyzed and determined more comprehensively, providing a rich data foundation for subsequent signal processing and discharge location determination.

[0043] S104, determine multiple signal band sets corresponding to multiple discharge pulse signals respectively, wherein each of the multiple signal band sets includes at least one signal band of the corresponding discharge pulse signal, and each of the multiple signal band sets corresponds to a different signal band category.

[0044] In step S104 of this application, a set of multiple signal bands corresponding to multiple discharge pulse signals is determined.

[0045] This involves multiple signal band sets, which are obtained by clustering the bands in each discharge pulse signal to obtain multiple waveform types of signal band sets, in order to remove irrelevant signals such as background white noise and periodic interference.

[0046] This involves signal bands, which are bands with specific characteristics (such as frequency range, time interval, waveform characteristics, etc.) extracted from discharge pulse signals.

[0047] This involves signal band categories, which are the result of classifying signal bands based on their characteristics (such as frequency range, waveform shape, amplitude, etc.). Signal band categories help distinguish between different types of signals, such as partial discharge signals and interference signals.

[0048] By classifying signal bands, interference signals can be removed more effectively, and useful partial discharge signals can be extracted, thereby improving the ability to avoid interference from complex environments in determining the discharge location.

[0049] S106, based on the multiple signal band sets corresponding to the multiple discharge pulse signals respectively, determine the signal polarity corresponding to the multiple discharge pulse signals respectively, wherein the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value.

[0050] In step S106 provided in this application, the signal polarity corresponding to each of the multiple discharge pulse signals is determined based on the multiple signal band sets corresponding to the multiple discharge pulse signals.

[0051] This involves signal polarity, which represents the positive or negative state of the discharge pulse signal value at a predetermined time relative to a predetermined reference value.

[0052] This involves the signal value at a predetermined time, which represents the signal value of the discharge pulse signal, such as voltage or current, at a pre-set time point.

[0053] This involves a predetermined reference value, which is a base value pre-set in signal processing to compare the positive and negative states of signal values. This reference value can be zero or a specific signal value (such as a specific current or voltage value), depending on the needs of signal processing.

[0054] When partial discharge occurs, the generated pulse signal propagates in the cable. Its polarity changes due to parameters such as the cable's capacitance and inductance, as well as the direction of signal propagation. This determines the signal polarity corresponding to each of the multiple discharge pulse signals, which helps to accurately locate the partial discharge position based on the changing pattern of signal polarity.

[0055] S108 determines the target discharge position corresponding to the power distribution cable based on the signal polarity corresponding to the multiple discharge pulse signals.

[0056] In step S108 provided in this application, the target discharge position corresponding to the power distribution cable is determined according to the signal polarity corresponding to the multiple discharge pulse signals.

[0057] This involves the target discharge location, which is the specific location where partial discharge actually occurs in the power distribution cable.

[0058] Signal polarity is affected by the electrical characteristics of the power distribution cable, the discharge location, and the signal propagation path during propagation. Therefore, by analyzing the signal polarity at different locations (such as the first core wire, the first grounding wire, the last core wire, and the last grounding wire), the specific location of partial discharge can be accurately determined.

[0059] Through the above steps S102-S108, multiple discharge pulse signals of the power distribution cable are acquired, wherein the multiple discharge pulse signals include the pulse signal of the first core wire of the power distribution cable, the pulse signal of the first ground wire of the power distribution cable, the pulse signal of the last core wire of the power distribution cable, and the pulse signal of the last ground wire of the power distribution cable; multiple signal band sets corresponding to the multiple discharge pulse signals are determined, wherein each set of multiple signal bands includes at least one signal band of the corresponding discharge pulse signal, and each set of multiple signal bands corresponds to a different signal band category; based on the multiple signal band sets corresponding to the multiple discharge pulse signals, the signal polarity corresponding to the multiple discharge pulse signals is determined, wherein the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value; based on the signal polarity corresponding to the multiple discharge pulse signals, the target discharge position corresponding to the power distribution cable is determined. Multiple discharge pulse signals are acquired from the core wires and grounding wires at both ends of the power distribution cable. These signals are then classified into different signal band sets, enabling a more systematic analysis of signal characteristics. This allows for accurate determination of the signal polarity of each discharge pulse signal. Since the signal polarity changes during propagation due to the electrical characteristics of the power distribution cable, the discharge location, and the signal propagation path, the location of partial discharge in the power distribution cable can be accurately determined based on the signal polarities corresponding to the multiple discharge pulse signals. This solves the technical problem in related technologies where the location of partial discharge in power distribution cables cannot be accurately determined under complex operating environments, thus hindering effective monitoring and diagnosis of partial discharge in power distribution cables.

[0060] As an optional embodiment, the signal polarity corresponding to each of the multiple discharge pulse signals is determined based on the multiple signal band sets corresponding to the multiple discharge pulse signals, including: determining the signal polarity corresponding to the target discharge pulse signal based on the target signal band set corresponding to any one of the multiple discharge pulse signals in the following manner: when the target signal band set includes multiple signal bands, a predetermined number of signal bands in the multiple signal bands are superimposed and averaged to obtain an array of multiple signal bands corresponding to the target discharge pulse signal; determining the peak value and peak value threshold corresponding to each of the multiple signal band arrays; determining the signal polarity corresponding to the target discharge pulse signal based on the peak value threshold and the peak value corresponding to each of the multiple signal band arrays; and obtaining the signal polarity corresponding to each of the other discharge pulse signals in the multiple discharge pulse signals besides the target discharge pulse signal by using the same method as obtaining the signal polarity corresponding to the target discharge pulse signal.

[0061] In this embodiment, specific steps are described to determine the signal polarity corresponding to each of the multiple discharge pulse signals based on the multiple signal band sets corresponding to the multiple discharge pulse signals.

[0062] This involves a target discharge pulse signal, which is any one of multiple discharge pulse signals.

[0063] This involves a set of target signal bands, which is a set of signal bands determined from multiple sets of signal bands of the corresponding target discharge pulse signal.

[0064] This involves a predetermined number of signal bands, which is a fixed number of signal bands pre-set during signal processing, used to select from the target signal band set for superposition and averaging. This predetermined number can be 64, meaning 64 signal bands are selected for superposition and averaging.

[0065] This involves multiple signal band arrays, which are arrays obtained by superimposing and averaging each predetermined number of signal bands.

[0066] This involves a peak threshold, which is a pre-set benchmark value in signal processing used to determine whether the peak values ​​in the signal band array are valid.

[0067] By selecting a predetermined number of signal bands for superposition and averaging, the influence of noise can be reduced, the signal-to-noise ratio can be improved, and the signal characteristics can be made more obvious. The resulting signal band array can more clearly reflect the signal characteristics, facilitating subsequent peak detection and polarity determination. Furthermore, by comparing the peak values ​​in the signal band array with a peak threshold, the polarity of the signal can be determined. If a peak value is greater than or equal to the peak threshold, it is considered valid and can be used for polarity determination; if a peak value is less than the peak threshold, it is considered likely noise and is not considered, thus further improving the accuracy and reliability of signal processing.

[0068] As an optional embodiment, the signal polarity corresponding to the target discharge pulse signal is determined based on a peak threshold and the peak values ​​corresponding to multiple signal band arrays, including: for any target signal band array in the multiple signal band arrays, the peak value of the corresponding target signal band is compared with the peak threshold one by one according to the execution order of the multiple target signal bands in the target signal band array, to obtain the waveform comparison result corresponding to the corresponding target signal band, until the waveform comparison result is that the peak value of the corresponding target signal band is greater than or equal to the peak threshold, thus obtaining the first wave corresponding to the target signal band array; the first wave corresponding to other signal band arrays in the multiple signal band arrays other than the target signal band array is obtained by using the method of obtaining the first wave corresponding to the target signal band array; and the signal polarity corresponding to the target discharge pulse signal is determined based on the first waves corresponding to the multiple signal band arrays.

[0069] This embodiment describes the specific steps for determining the signal polarity corresponding to the target discharge pulse signal based on the peak threshold and the peak values ​​corresponding to multiple signal band arrays.

[0070] This involves a target signal band array, which is a signal band array determined from multiple corresponding signal band arrays.

[0071] This involves waveform comparison results, which are obtained by comparing the peak value of each signal band with a peak value threshold. If the peak value is greater than or equal to the threshold, the waveform comparison result is valid; if the peak value is less than the threshold, the waveform comparison result is invalid.

[0072] This involves the first wave, which is the first signal band in the target signal band array whose peak value is greater than or equal to the peak threshold. The first wave is used to represent the polarity of the target discharge pulse signal.

[0073] The first waveform is the first significant response during signal propagation. Subsequent waveforms (such as the second and third waves) are usually responses after the signal has been reflected, refracted, or propagated multiple times during propagation. These waveforms may be affected by various factors, such as the electrical characteristics of the cable, the signal propagation path, and the reflection point, which cause their characteristics to differ from the initial signal. Starting from the beginning of the signal band array, by comparing the peak value of each signal band with the peak value ratio threshold, the first significant signal band in the signal band array can be accurately identified.

[0074] As an optional embodiment, determining a set of multiple signal bands corresponding to multiple discharge pulse signals includes: determining signal characteristic parameters corresponding to multiple discharge pulse signals, wherein the signal characteristic parameters include equivalent duration, equivalent bandwidth, and signal amplitude ratio; and performing clustering operations on the multiple signal bands included by the multiple discharge pulse signals based on the signal characteristic parameters corresponding to the multiple discharge pulse signals to obtain a set of multiple signal bands corresponding to the multiple discharge pulse signals.

[0075] In this embodiment, specific steps for determining multiple signal band sets corresponding to multiple discharge pulse signals are described.

[0076] This involves signal characteristic parameters, which are various parameters used to describe the characteristics of a signal. These parameters can reflect the signal's time, frequency, and amplitude characteristics, including equivalent duration, equivalent bandwidth, and signal amplitude ratio.

[0077] This involves the equivalent duration, which is the effective duration of the signal in the time domain. It can be calculated through the energy distribution of the signal and reflects the degree of concentration of the signal in time.

[0078] Equivalent duration can be used to describe the time-domain characteristics of a signal, helping to distinguish between different types of signals. For example, partial discharge signals typically have a short equivalent duration, while interference signals may have a longer equivalent duration. By calculating the equivalent duration, we can better understand the time-domain behavior of a signal and provide a basis for subsequent signal classification.

[0079] This involves the equivalent bandwidth, which is the effective bandwidth of the signal in the frequency domain. It can be calculated through the signal's spectral distribution and reflects the degree of concentration of the signal in the frequency domain.

[0080] Equivalent bandwidth can be used to describe the frequency domain characteristics of a signal, helping to distinguish between different types of signals. For example, partial discharge signals typically have a wide equivalent bandwidth, while interference signals may have a narrow equivalent bandwidth. By calculating the equivalent bandwidth, we can better understand the frequency domain behavior of a signal and provide a basis for subsequent signal classification.

[0081] This involves the signal amplitude ratio, which is the ratio of the signal amplitude at different locations or on different channels. This includes the amplitude ratio of the first-end core wire to the last-end core wire, and the amplitude ratio of the first-end ground wire to the last-end ground wire, etc.

[0082] The signal amplitude ratio reflects the attenuation or enhancement of a signal during propagation, helping to determine the signal's propagation path and source. Calculating the signal amplitude ratio allows for a better understanding of the signal's propagation characteristics, providing a basis for subsequent signal classification and discharge location.

[0083] This involves clustering, a process of dividing a set of data points into multiple clusters, such that data points within the same cluster have high similarity, while data points in different clusters have low similarity. In partial discharge detection, clustering is used to divide different signal bands into different categories, with each category containing signal bands with similar characteristics.

[0084] Clustering operations can group signal bands with similar characteristics into one category, thereby achieving signal classification and feature extraction. Clustering can help distinguish between different types of signals, such as partial discharge signals and interference signals, improving the accuracy and reliability of signal processing.

[0085] As an optional embodiment, based on the signal characteristic parameters corresponding to the multiple discharge pulse signals, a clustering operation is performed on the multiple signal bands included in the multiple discharge pulse signals to obtain multiple signal band sets corresponding to the multiple discharge pulse signals. This includes: for any target discharge pulse signal among the multiple discharge pulse signals, determining the proximity index between any two signal bands among the multiple signal bands, where the proximity index represents the degree of proximity between any two signal bands; and based on the proximity index between any two signal bands among the multiple signal bands, determining a set of neighboring bands corresponding to each of the multiple signal bands, where the corresponding set of neighboring bands includes at least one neighboring band, and the neighboring band is the signal band corresponding to the signal band. Other signal bands whose proximity index is greater than the proximity threshold; based on the neighboring band sets corresponding to multiple signal bands, determine the mutually adjacent bands corresponding to the multiple signal bands, where mutually adjacent bands are signal bands that are adjacent to the corresponding signal bands; based on the mutually adjacent bands corresponding to the multiple signal bands, determine the neighboring band distribution density corresponding to the multiple signal bands; based on the neighboring band distribution density corresponding to the multiple signal bands, determine the set of multiple signal bands corresponding to the target discharge pulse signal; using the method of obtaining the set of multiple signal bands corresponding to the target discharge pulse signal, obtain the set of multiple signal bands corresponding to the other discharge pulse signals besides the target discharge pulse signal in the multiple discharge pulse signals.

[0086] In this embodiment, the specific steps are described to perform clustering operations on the multiple signal bands included by the multiple discharge pulse signals according to the signal characteristic parameters corresponding to the multiple discharge pulse signals, so as to obtain a set of multiple signal bands corresponding to the multiple discharge pulse signals.

[0087] This includes the proximity index, which measures the similarity or proximity between any two signal bands.

[0088] This involves a neighboring band set, which is a collection of other signal bands whose proximity index is greater than a preset proximity threshold to the corresponding signal band. These bands are similar to the corresponding signal band in waveform characteristics. An upper limit can be set on the number of neighboring bands included in the neighboring band set; that is, the number of neighboring bands cannot exceed this upper limit to ensure a balance between computational resources and clustering accuracy. To achieve this, the neighboring bands with the highest proximity index are selected from among the multiple neighboring bands and placed into the set.

[0089] This involves neighboring bands, which are other signal bands whose proximity index to the corresponding signal band is greater than a preset proximity threshold. These bands are similar to the corresponding signal band in terms of their waveform characteristics.

[0090] This involves a proximity threshold, which is a preset threshold used to determine whether the proximity index between two signal bands is large enough to decide whether to classify them into the same category.

[0091] This involves neighboring bands, which are signal bands that are adjacent to each other. That is, the proximity index of two signal bands is greater than a preset proximity threshold. Considering that the neighboring bands included in the set of neighboring bands corresponding to each signal band may be inconsistent, neighboring bands are further identified to further filter and confirm the similarity of signal bands, ensuring the accuracy of the clustering operation.

[0092] This involves the neighboring band distribution density, which represents the concentration, number, and distribution of neighboring bands of a signal band. It reflects the density of signal bands in the feature space. The neighboring band distribution density is used to assess the clustering of signal bands; a higher density indicates that the signal bands are more concentrated in the feature space and may belong to the same class of signals.

[0093] By calculating the proximity index between any two signal bands to measure their similarity, and filtering out neighboring band sets based on a preset proximity threshold, further identifying mutually adjacent bands helps to accurately identify signal bands with similar characteristics, ensuring the accuracy of clustering operations. Analyzing the distribution density of neighboring bands allows for the assessment of signal band clustering in the feature space, thereby grouping signal bands with similar characteristics into the same category to obtain a set of signal bands for each category. This not only improves the accuracy of signal classification but also...

[0094] As an optional embodiment, determining the signal amplitude ratio corresponding to each of the multiple discharge pulse signals includes: determining a first amplitude ratio between the first-end core wire pulse signal and the last-end core wire pulse signal; determining a second amplitude ratio between the first-end ground wire pulse signal and the last-end ground wire pulse signal; determining a third amplitude ratio between the first-end core wire pulse signal and the first-end ground wire pulse signal; determining a fourth amplitude ratio between the last-end core wire pulse signal and the last-end ground wire pulse signal; and determining the signal amplitude ratio corresponding to each of the multiple discharge pulse signals based on the first amplitude ratio, the second amplitude ratio, the third amplitude ratio, and the fourth amplitude ratio.

[0095] In this embodiment, specific steps for determining the signal amplitude ratios corresponding to the multiple discharge pulse signals are described.

[0096] This involves the first amplitude ratio, which is the amplitude ratio between the pulse signal of the first-end core wire and the pulse signal of the last-end core wire. The first amplitude ratio can reflect the attenuation or amplification of the signal between the first and last core wires of the cable.

[0097] This involves a second amplitude ratio, which is the amplitude ratio between the pulse signal of the end core wire and the pulse signal of the end ground wire. The second amplitude ratio can reflect the attenuation or amplification of the signal between the cable head end and the end ground wire.

[0098] This involves a third amplitude ratio, which reflects the attenuation or amplification of the signal in the cable.

[0099] This involves a fourth amplitude ratio, which can reflect the attenuation or enhancement of the signal at the end.

[0100] Different types of signals exhibit different propagation characteristics in cables. Partial discharge signals and interference signals may show different attenuation or enhancement characteristics during propagation. By analyzing the amplitude ratio, the propagation path of the signal can be identified, and it can be determined whether the signal has passed through a specific path or reflection point. By determining the first, second, third, and fourth amplitude ratios, the amplitude relationship between pulse signals at different locations can be quantified. This allows for a comprehensive reflection of the signal attenuation or enhancement in different segments of the cable, which in turn helps identify the signal propagation path and characteristics, improves the accuracy of distinguishing partial discharge signals from interference signals, and ultimately helps to more accurately determine the discharge location.

[0101] As an optional embodiment, acquiring multiple discharge pulse signals of a power distribution cable includes: acquiring multiple initial pulse signals corresponding to the power distribution cable; determining multiple signal pairs from the multiple initial pulse signals; performing waveform matching on a first pulse signal and a second pulse signal included in any target signal pair among the multiple signal pairs to obtain a matching result corresponding to the target signal pair, wherein the target signal pair includes a first pulse signal and a second pulse signal, the first pulse signal and the second pulse signal being acquired from different locations on the power distribution cable respectively; obtaining matching results corresponding to the target signal pairs by using the method of obtaining matching results corresponding to the target signal pairs, and obtaining matching results corresponding to other signal pairs besides the target signal pairs respectively; and determining multiple discharge pulse signals from the multiple initial pulse signals based on the matching results corresponding to the multiple signal pairs respectively.

[0102] In this embodiment, the specific steps for acquiring multiple discharge pulse signals of the power distribution cable are described.

[0103] This involves multiple signal pairs, which are combinations of pairs of signals selected from multiple initial pulse signals. Each signal pair consists of two pulse signals, which are collected from different locations on the power distribution cable.

[0104] This involves waveform matching, which refers to comparing the waveforms of two pulse signals to determine their similarity.

[0105] Waveform matching is used to assess the similarity between two signals. For example, by comparing the waveform shape, amplitude, and timing characteristics of the signals, it can be determined whether they come from the same discharge event or whether they are related.

[0106] This involves the matching result, which is obtained by waveform matching of the target signal pair to determine whether the two signals match. If the matching result shows that the two signals are highly similar, they can be considered to have originated from the same event (such as a discharge event); if the matching result shows that the two signals are dissimilar, they can be considered to have originated from different events or noise.

[0107] This involves multiple initial pulse signals, which are raw pulse signals collected from different locations on the power distribution cable. These initial pulse signals may originate from different discharge events.

[0108] In complex signal environments, initial pulse signals may contain signals, noise, or other interference signals from different discharge events. By acquiring multiple initial pulse signals from different locations on the power distribution cable and identifying multiple signal pairs, waveform matching can be performed on each pair to obtain the matching results. This effectively identifies which signals originate from the same discharge event, thus filtering out discharge pulse signals from the same event from numerous initial pulse signals. This avoids the inaccurate determination of discharge location caused by signals from different events being mixed together.

[0109] As an optional embodiment, waveform matching is performed on the first pulse signal and the second pulse signal included in any target signal pair among multiple signal pairs to obtain a matching result corresponding to the target signal pair. This includes: for any target first signal band among multiple first signal bands included in the first pulse signal, determining the band matching degree between the target first signal band and the multiple second signal bands included in the second pulse signal, and obtaining multiple band matching degrees corresponding to the target first signal band; using the method of obtaining multiple band matching degrees corresponding to the target first signal band, obtaining multiple band matching degrees corresponding to the other first signal bands among the multiple first signal bands besides the target first signal band; and obtaining the matching result corresponding to the target signal pair based on the multiple band matching degrees corresponding to the multiple first signal bands.

[0110] In this embodiment, specific steps are described to perform waveform matching on the first pulse signal and the second pulse signal included in any one of the multiple signal pairs to obtain a matching result corresponding to the target signal pair.

[0111] This involves a target first signal band, which is any first signal band selected from the first pulse signal, used to compare the matching degree with multiple signal bands in the second pulse signal.

[0112] This involves band matching, which represents the degree of similarity between two signal bands. For example, it can be calculated by comparing the shape, amplitude, and timing characteristics of the signal bands. A high band matching indicates that the two signal bands are very similar in shape, amplitude, and timing, and may originate from the same discharge event; a low band matching indicates that the two signal bands are dissimilar, and may originate from different events or contain noise.

[0113] This involves multiple first signal bands, which are all the signal bands contained in the first pulse signal. These signal bands are components of the first pulse signal, with each band representing a specific part of the signal.

[0114] This involves multiple second signal bands, which are all the signal bands contained in the second pulse signal. These signal bands are components of the second pulse signal, with each band representing a specific part of the signal.

[0115] This method allows for the analysis of the similarity between each signal band in the first pulse signal and the signal band in the second pulse signal. This avoids misjudgments caused by similar global features but inconsistent local features, as well as misjudgments caused by time misalignment of signals. As a result, the similarity between the two pulse signals can be evaluated more comprehensively, and the accuracy and reliability of waveform matching can be improved.

[0116] As an optional embodiment, the target discharge position corresponding to the power distribution cable is determined based on the signal polarity corresponding to the multiple discharge pulse signals, including: determining a first comparison result between the signal polarity of the first-end core wire pulse signal and the signal polarity of the last-end core wire pulse signal; determining the initial discharge position corresponding to the power distribution cable based on the first comparison result; determining a second comparison result between the signal polarity of the first-end grounding wire pulse signal and the signal polarity of the last-end grounding wire pulse signal; and verifying the initial discharge position based on the second comparison result to obtain the discharge position corresponding to the power distribution cable.

[0117] This embodiment describes the specific steps for determining the target discharge location corresponding to the power distribution cable based on the signal polarity corresponding to the multiple discharge pulse signals.

[0118] This involves a first comparison result, which is a comparison between the signal polarity of the pulse signal at the beginning of the core wire and the signal polarity of the pulse signal at the end of the core wire, used to preliminarily determine the location of partial discharge.

[0119] This involves the initial discharge location, which is the approximate location of the partial discharge preliminarily determined based on the first comparison results. This location is a preliminary estimate and requires further verification.

[0120] This includes a second comparison result, which is a comparison between the signal polarity of the first-end grounding wire pulse signal and the signal polarity of the last-end grounding wire pulse signal, used to further verify and refine the initial discharge location.

[0121] This involves auxiliary verification, which uses the second comparison results to further confirm and verify the initial discharge location. This further auxiliary verification can improve the accuracy of discharge location determination and reduce misjudgments.

[0122] Based on the above embodiments and optional embodiments, an optional implementation method is provided, which is described in detail below.

[0123] In related technologies, the operating environment of power distribution cables is complex. The operation of surrounding power electronic devices and the discharge of nearby equipment can generate strong pulse current signals, which can interfere with the detection of partial discharges within the power distribution cable. Therefore, in complex operating environments, related technologies face the technical challenge of accurately determining the location of partial discharges in power distribution cables, thus hindering effective monitoring and diagnosis of partial discharges.

[0124] Specifically, when applying the pulse current method for online real-time monitoring of distribution cables, the complex operating environment presents various types of interference, primarily including white noise, narrowband interference, and pulse-type interference. During partial discharge detection of distribution cables, relatively weak partial discharge pulse current signals can be submerged in white noise interference and become unrecognizable. Furthermore, narrowband interference from power grid communication and high-frequency protection, as well as pulse-type interference from discharges in nearby equipment or lines, can interfere with partial discharge detection, leading to misjudgments. Therefore, accurate identification and location of partial discharge signals in distribution cables becomes impossible.

[0125] In related technologies, the main components of narrowband interference spectrum are relatively concentrated, while the spectrum of partial discharge signals is relatively dispersed. Furthermore, the spectral characteristics of narrowband interference vary under different weather conditions and in different regions. Therefore, selecting the threshold based on digital denoising methods (such as digital filters, wavelet analysis, and empirical mode decomposition) is quite difficult. Simultaneously, because certain characteristic quantities of different signal types differ, commonly used methods for extracting feature parameters of partial discharge signals (such as time-frequency analysis, equivalent time-frequency entropy algorithms, and equivalent time-frequency entropy classification spectra) are easily affected by the testing environment and cannot identify which type of signal is a valid signal containing partial discharge information.

[0126] Furthermore, pulse-type interference differs from partial discharge signals in its propagation characteristics within the transformer, exhibiting different signal characteristics at different detection ports. Related techniques have used pulse injection to study the initial polarity of different pulse types at various ports; however, external interference shares the same polarity as internal non-winding discharge, and can only be distinguished using energy percentage.

[0127] Therefore, when performing partial discharge pulse current detection on power distribution cables, due to environmental interference and the complex transmission path of discharge pulses, the equivalent time and frequency of various pulses are relatively dispersed. It may not be possible to achieve effective pulse separation by using a single amplitude ratio or time and frequency characteristic. Furthermore, in the polarity identification process, the first wave is not easy to read and the success rate is low, which leads to the inability to accurately determine the discharge position of the power distribution cable.

[0128] There is currently no effective solution to the above problems.

[0129] In view of this, an optional embodiment of the present invention provides a method for determining the discharge location of a power distribution cable, which can effectively solve the above-mentioned technical problems existing in related technologies.

[0130] Figure 2 This is a flowchart of a method for determining the discharge location of a power distribution cable in an optional embodiment of the present invention. Figure 3 This is a schematic diagram of multi-terminal signal acquisition of a cable in an optional embodiment of the present invention, as shown below. Figure 2 ,as well as Figure 3 As shown.

[0131] S1. Acquire signals through acquisition equipment to obtain multiple discharge pulse signals of the power distribution cable, wherein the multiple discharge pulse signals include the pulse signal of the first core wire of the power distribution cable, the pulse signal of the first grounding wire of the power distribution cable, the pulse signal of the last core wire of the power distribution cable, and the pulse signal of the last grounding wire of the power distribution cable.

[0132] Specifically, multiple discharge pulse signals of the power distribution cable are obtained through the following methods:

[0133] Multiple initial pulse signals corresponding to the power distribution cable are acquired; multiple signal pairs are determined from the multiple initial pulse signals; waveform matching is performed on the first pulse signal and the second pulse signal included in any target signal pair among the multiple signal pairs to obtain the matching result corresponding to the target signal pair, wherein the target signal pair includes: the first pulse signal and the second pulse signal, which are acquired from different locations on the power distribution cable; by using the method of obtaining the matching result corresponding to the target signal pair, the matching results corresponding to the other signal pairs of the multiple signal pairs are obtained respectively; based on the matching results corresponding to the multiple signal pairs respectively, multiple discharge pulse signals are determined from the multiple initial pulse signals.

[0134] Specifically, waveform matching is performed on the first pulse signal and the second pulse signal of any target signal pair among multiple signal pairs to obtain a matching result corresponding to the target signal pair, including:

[0135] For any target first signal band among the multiple first signal bands included in the first pulse signal, determine the band matching degree between the target first signal band and the multiple second signal bands included in the second pulse signal, and obtain the multiple band matching degrees corresponding to the target first signal band; using the same method as obtaining the multiple band matching degrees corresponding to the target first signal band, obtain the multiple band matching degrees corresponding to the other first signal bands besides the target first signal band; based on the multiple band matching degrees corresponding to the multiple first signal bands, obtain the matching result corresponding to the target signal pair. An improved Dynamic Time Warping (DTW) algorithm can be used to perform waveform matching on the signal waveforms acquired at the cable's head and tail. DTW adopts a "one-to-many" data point matching mode, which can not only measure sequences of unequal lengths but also has significant advantages in sequence morphology measurement, accurately matching the morphological characteristics of the sequence such as peaks, troughs, and abrupt changes, greatly improving the practicality and accuracy of the measurement. The steps are as follows:

[0136] For any target signal pair among multiple signal pairs, the time sequence of the first pulse signal is represented as: The time series of the second pulse signal is represented as follows: ,in, , These are the lengths of sequences X and Y, respectively. For multiple first signal bands, It consists of multiple second signal bands.

[0137] First, calculate the distance between any two points using Euclidean distance. The distance between (i.e., any first signal band and second signal band) is calculated (same as the band matching degree mentioned above), and a distance matrix is ​​formed. The formula is:

[0138]

[0139] Secondly, from Start calculating point by point End, and from point X and Y in sequence X and Y. Time With the goal of minimizing the cumulative distance, find an optimal curved path. Ultimately, the cumulative distance corresponding to this curved path P is the DTW distance between the two sequences (same as the matching result above).

[0140] Finally, synchronous acquisition of the same pulse current at different acquisition terminals was achieved.

[0141] Before performing waveform matching on the signal waveforms acquired at the cable start and end points using the improved dynamic time bending algorithm, the following steps are also included:

[0142] Signals were collected from four detection sections, including the cable's two-terminal core wires and the grounding wire, and microsecond-level clock synchronization was performed. The waveforms at both ends were then matched. The steps were as follows:

[0143] A1. Collect pulse signal data (same as the multiple initial pulse signals mentioned above) from four sensors installed at both ends of the cable, including the grounding wire and the core wire.

[0144] A2. For the same pulse signal collected by different detection terminals in A1, high-precision satellite B-code synchronization technology is used for clock synchronization.

[0145] Figure 4 This is a schematic diagram of the acquisition module structure in an optional embodiment of the present invention, such as... Figure 4 As shown, it includes: a Global Positioning System (GPS) antenna, a B-code antenna, a time synchronization device, a B-code cable, a storage device, a pulse current acquisition device (including acquisition card 1 and acquisition card 2), and a pulse current sensor.

[0146] Using B-code timing, multi-channel synchronous acquisition between the same or different acquisition boards can be achieved with a synchronization error of less than 10ns. This enables the synchronous acquisition of the signal response of the same pulse current generated by the pulse source propagating to different ports.

[0147] S2. Determine multiple signal band sets corresponding to multiple discharge pulse signals respectively, wherein each set of multiple signal bands includes at least one signal band of the corresponding discharge pulse signal, and each set of multiple signal bands corresponds to a different signal band category.

[0148] Specifically, the acquired and synchronized raw waveforms undergo multi-dimensional parameter calculations. A high-dimensional clustering separation method is used to classify the raw waveforms and remove irrelevant signals such as background noise. The steps are as follows:

[0149] B1. Determine the signal characteristic parameters corresponding to the multiple discharge pulse signals, including the equivalent duration, equivalent bandwidth, and signal amplitude ratio; that is, for the obtained synchronization waveform (same as the multiple discharge pulse signals mentioned above), calculate the signal amplitude ratio at the core wires at both ends and the signal amplitude ratio at the ground wires at both ends; calculate the signal amplitude ratio at the core wires and ground wires at the beginning and end; calculate the equivalent duration and equivalent bandwidth of the pulse signal at each end.

[0150] For example, calculate the signal amplitude ratio at the core wires at both ends and the signal amplitude ratio at the ground wires at both ends; calculate the signal amplitude ratio at the core wires and ground wires at the beginning and end of the circuit respectively; specifically:

[0151] Determine the first amplitude ratio between the first-end core wire pulse signal and the last-end core wire pulse signal; determine the second amplitude ratio between the last-end core wire pulse signal and the last-end ground wire pulse signal; determine the third amplitude ratio between the first-end core wire pulse signal and the first-end ground wire pulse signal; determine the fourth amplitude ratio between the last-end core wire pulse signal and the last-end ground wire pulse signal; based on the first amplitude ratio, the second amplitude ratio, the third amplitude ratio, and the fourth amplitude ratio, determine the signal amplitude ratios corresponding to the multiple discharge pulse signals respectively.

[0152] The equivalent duration and equivalent bandwidth of the pulse signal at each end are calculated, and finally the signal characteristic parameters corresponding to the multiple discharge pulse signals are obtained.

[0153] B2. Based on the signal characteristic parameters corresponding to the multiple discharge pulse signals, clustering is performed on the multiple signal bands included in each discharge pulse signal to obtain a set of multiple signal bands corresponding to each discharge pulse signal. The DPC algorithm based on K-nearest neighbors and kernel density estimation can be used to perform high-dimensional clustering and separation of each pulse signal using the above parameters as different dimensions, obtaining waveform arrays of various pulse signals (similar to the sets of multiple signal bands corresponding to the multiple discharge pulse signals mentioned above). Figure 5 This is an overall flowchart of the high-dimensional clustering separation method in an optional embodiment of the present invention, such as... Figure 5 As shown, multidimensional parameter calculations are performed on the acquired and synchronized original waveforms. A high-dimensional clustering separation method is used to classify the original waveforms and remove irrelevant signals such as background white noise and periodic interference. Specifically, this includes:

[0154] For any target discharge pulse signal among multiple discharge pulse signals, determine the proximity index between any two signal bands, where the proximity index represents the degree of proximity between any two signal bands. Based on the proximity index between any two signal bands, determine the set of neighboring bands corresponding to each of the multiple signal bands, where each set of neighboring bands includes at least one neighboring band, and a neighboring band is any other signal band whose proximity index with the corresponding signal band is greater than a proximity threshold. This is achieved through the following method:

[0155] Input the various parameters obtained from the calculated pulse signal waveform (the signal characteristic parameters corresponding to the multiple discharge pulse signals mentioned above) as a high-dimensional dataset. Enter the number of nearest neighbors k.

[0156] For any target discharge pulse signal among multiple discharge pulse signals, determine the proximity index between any two signal bands, i.e., the Euclidean distance between data points (as described above, between any two signal bands). And construct the distance matrix (Same as the adjacent band set mentioned above).

[0157]

[0158]

[0159] in:

[0160] The total number of multiple signal bands in the target discharge pulse signal;

[0161] The first in the target discharge pulse signal One signal band;

[0162] In the target discharge pulse signal Each signal band.

[0163] Based on the neighboring band sets corresponding to multiple signal bands, mutually adjacent bands corresponding to each of the multiple signal bands are determined, where mutually adjacent bands are signal bands that are adjacent to the corresponding signal bands; this is achieved through the following method:

[0164] According to the distance matrix Obtain the k-nearest neighbor distance of the data points. (Similar to the aforementioned nearest band set, i.e., the k-th nearest neighbor set), the formula is:

[0165]

[0166] in:

[0167] For signal band The set of the kth nearest neighbors (same as the set of neighboring bands mentioned above);

[0168] For signal band and signal band The distance between them;

[0169] For range signal band The k nearest neighbor data point (i.e., the signal band);

[0170] For signal band and range signal band The distance between the k-th nearest neighbor data points.

[0171] Get the number of K nearest neighbors of a data point (Same as the number of adjacent bands mentioned above), where, if =1 indicates and They are neighbors (i.e.) yes (adjacent bands), and vice versa.

[0172] express The number of nearest neighbors (same as the neighboring bands mentioned above), if the data points The fact that there is more than one k-th nearest neighbor may lead to... The value is greater than k, so a constraint is added to the number of K nearest neighbors: .

[0173]

[0174]

[0175] in:

[0176] This is an indicator function used to determine data points. and data points Are they neighbors?

[0177] Representing data points Belongs to data points The set of the k-th nearest neighbors;

[0178] Representing data points Belongs to data points The set of the k-th nearest neighbors.

[0179] Based on the neighboring bands corresponding to multiple signal bands, determine the distribution density of the neighboring bands corresponding to each of the multiple signal bands. This can be achieved in the following way:

[0180] Calculate the local kernel density of the data points using the Gaussian kernel function and the KDE algorithm. The formula is:

[0181]

[0182]

[0183] in:

[0184] Gaussian kernel function at data points The value at;

[0185] For data points The k nearest neighbors (same as the neighboring band set mentioned above);

[0186] for The norm;

[0187] For data points Data points with the k nearest neighbor The distance between them, where d is the data dimension.

[0188] The number of K nearest neighbors of data points Local kernel density of data points The local density of the data points is obtained by adding them together. (Similar to the distribution density of adjacent bands mentioned above), the new local density replaces the local density calculated based on the cutoff distance in the traditional DPC algorithm. And calculate the relative distance. As shown in the following formula:

[0189]

[0190]

[0191] in:

[0192] This refers to the local density, that is, the distribution density of adjacent bands;

[0193] It is a relative distance;

[0194] For local density Greater than local density data points A set;

[0195] For data points and data points The distance between them.

[0196] Finally, based on the distribution density of neighboring bands corresponding to multiple signal bands, a set of multiple signal bands corresponding to the target discharge pulse signal is determined, that is, the arrays of various pulse signal waveforms from each acquisition end after clustering and separation are obtained. This is achieved through the following method:

[0197] Based on local density and relative distance Constructing a decision graph to select cluster centers and assign class tags Non-central data points are sequentially assigned to the classes of the nearest data points with higher local density, thus obtaining the class labels for the dataset (similar to the aforementioned sets of multiple signal bands). .

[0198] By obtaining multiple signal band sets corresponding to the target discharge pulse signal, multiple signal band sets corresponding to other discharge pulse signals besides the target discharge pulse signal are obtained respectively.

[0199] S3. Based on the multiple signal band sets corresponding to the multiple discharge pulse signals, determine the signal polarity corresponding to the multiple discharge pulse signals respectively, wherein the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value.

[0200] Specifically, the signal polarity corresponding to the target discharge pulse signal is determined based on the target signal band set corresponding to any one of the multiple discharge pulse signals in the following manner:

[0201] When the target signal band set includes multiple signal bands, a predetermined number of signal bands from the multiple signal bands are superimposed and averaged to obtain an array of multiple signal bands corresponding to the target discharge pulse signal.

[0202] Figure 6 This is a flowchart illustrating the calculation of the polarity of the first wave of the pulse signal in an optional embodiment of the present invention, as shown below. Figure 6 As shown, the polarity of the first wave is calculated based on multiple similar waveforms obtained from clustering.

[0203] For example, the partial discharge signal pulse waveforms of each acquisition end are superimposed and averaged. A robust waveform array (same as the signal band array mentioned above) is fitted from every 64 waveforms (the same number as the predetermined number mentioned above).

[0204] Determine the peak values ​​and peak thresholds corresponding to multiple signal band arrays respectively; based on the peak thresholds and the peak values ​​corresponding to multiple signal band arrays respectively, determine the signal polarity corresponding to the target discharge pulse signal, wherein, for ease of comparison, the peak value is the absolute value of the peak value;

[0205] For example, calculate the absolute value of the peak value of the pulse waveform array for each type of partial discharge signal, and multiply it by 0.2 as the threshold value for distinguishing the first wave (same as the peak value threshold mentioned above) (based on statistical analysis, the peak value ratio of the first wave is ≥0.2).

[0206] Among them, based on the peak threshold and the peak values ​​corresponding to multiple signal band arrays, the signal polarity corresponding to the target discharge pulse signal is determined, including:

[0207] For any target signal band array in multiple signal band arrays, the peak value of each target signal band is compared with a peak threshold according to the execution order of the multiple target signal bands in the target signal band array, and the waveform comparison result corresponding to the corresponding target signal band is obtained, until the waveform comparison result is that the peak value of the corresponding target signal band is greater than or equal to the peak threshold, and the first wave corresponding to the target signal band array is obtained; the first wave corresponding to the target signal band array is obtained by using the same method as obtaining the first wave corresponding to the target signal band array; based on the first wave corresponding to each of the multiple signal band arrays, the signal polarity corresponding to the target discharge pulse signal is determined.

[0208] For example, starting from the beginning of the waveform array (same as the signal band array mentioned above), scan each element backward (index) to find the first threshold element whose absolute value is greater than or equal to the peak threshold. This element is then determined to be the first wave point (i.e., the first wave).

[0209] Based on the first wave corresponding to each of the multiple signal band arrays, the signal polarity corresponding to the target discharge pulse signal is determined. That is, if the value of the first wave point is greater than 0, the polarity code 1 (representing positive polarity) is output; if the value of the first wave point is less than 0, the polarity code 0 (representing negative polarity) is output.

[0210] By obtaining the signal polarity corresponding to the target discharge pulse signal, the signal polarity corresponding to other discharge pulse signals besides the target discharge pulse signal among multiple discharge pulse signals is obtained.

[0211] S4. Determine the target discharge location corresponding to the power distribution cable based on the signal polarity corresponding to the multiple discharge pulse signals.

[0212] Specifically, the target discharge location corresponding to the power distribution cable is determined based on the signal polarities of multiple discharge pulse signals, including: determining a first comparison result between the signal polarities of the pulse signals of the first and last core wires; determining the initial discharge location corresponding to the power distribution cable based on the first comparison result; determining a second comparison result between the signal polarities of the pulse signals of the first and last grounding wires; and verifying the initial discharge location based on the second comparison result to obtain the discharge location corresponding to the power distribution cable. The determination of the partial discharge location in the power distribution cable can also be achieved using a pulse generation segment identification method based on the four-terminal pulse current polarity, with the following steps:

[0213] A logic discrimination algorithm was developed using a power distribution cable pulse polarity library obtained from simulation tests. Based on the first wave polarity of various pulse signals from the four acquisition terminals, the pulse signal segments were identified.

[0214] A pulse generation section identification method based on four-terminal pulse current polarity is used to determine the location of partial discharge in power distribution cables. This includes:

[0215] C1. Input the initial polarity data of the four detection terminals, with positive polarity marked as 1 and negative polarity marked as 0. Record the polarity of the grounding wire at the cable head as... The polarity of the first core wire is The polarity of the end grounding wire is The polarity of the end core wire is .

[0216] C2. Using the pulse signal polarity library obtained from simulation tests at each measuring point of the power distribution cable, the polarity of the pulse signal position is determined:

[0217] Table 1 is a library of pulse signal polarities at various measuring points of the power distribution cable, as shown in Table 1.

[0218] Table 1

[0219]

[0220] like = If the polarity of the core wires at the beginning and end of the cable is the same, then the signal is determined to originate inside the cable.

[0221] like ≠ (The polarity of the core wires at the beginning and end of the cable is different):

[0222] when =0、 When =1 (the first core wire is negative and the last core wire is positive), the signal is determined to originate from the beginning of the cable.

[0223] when =1、 When the polarity is 0 (the first core wire is positive and the last core wire is negative), the signal is determined to originate from the end of the cable.

[0224] C3. Auxiliary verification of polarity determination:

[0225] If determined to be inside the cable: , It should be 0, meaning the polarity of the beginning and end should be negative; if it does not meet the requirement, output "Data error";

[0226] If it is determined to be the beginning of the cable: It should be 1. It should be 0, meaning the first polarity is positive and the last polarity is negative; if it does not meet the requirement, output "data error";

[0227] If it is determined to be the end of a cable: It should be 0. It should be 1, meaning the first polarity is negative and the last polarity is positive; if it does not meet the requirement, output "data error";

[0228] C4. Return to the final determination location: "Cable start", "Cable interior", or "Cable end". If an anomaly is detected, a warning message will be output.

[0229] Based on the above steps, the problems of anti-interference methods being unable to achieve effective pulse separation and the difficulty in reading the first wave of polarity identification can be effectively solved, thereby achieving accurate positioning of the discharge location of the power distribution cable.

[0230] The above optional implementation methods can achieve at least the following beneficial effects:

[0231] (1) Compared with related technologies, this invention uses a high-dimensional clustering separation method to extract and calculate multi-dimensional feature parameters of the original waveform as the dimensions for clustering separation, including the amplitude ratio, equivalent duration, and equivalent bandwidth among the four acquisition ends. At the same time, the clustering separation algorithm adopts the DPC algorithm based on K-nearest neighbors and kernel density estimation. This algorithm can reduce parameter sensitivity, adapt to the high-dimensional features (amplitude ratio, equivalent duration, bandwidth, etc.) of power distribution cable pulse signals, and solve the separation failure problem of traditional methods such as K-means and DBSCAN under complex interference.

[0232] (2) Compared with related technologies, this invention synchronously collects signals through four independent channels—the grounding wire and the core wire—at the beginning and end of the cable, and obtains a pulse signal polarity library for each measuring point through simulation testing. Based on this, a logical discrimination method for the cable pulse generation section is established. Compared with the traditional double-end detection of cables, a low signal-to-noise ratio on the grounding wire may affect the polarity discrimination effect. The four-end detection can still provide effective polarity information in the other channels when the signal-to-noise ratio of any channel is too low, thus realizing the differentiation of interference.

[0233] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0234] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0235] Example 2

[0236] According to an embodiment of the present invention, an apparatus for implementing the above-described method for determining the discharge location of a power distribution cable is also provided. Figure 7 This is a structural block diagram of a power distribution cable discharge location determination device according to an embodiment of the present invention, as shown below. Figure 7 As shown, the device includes: an acquisition module 702, a first determination module 704, a second determination module 706, and a third determination module 708. The device will be described in detail below.

[0237] The acquisition module 702 is used to acquire multiple discharge pulse signals of the power distribution cable, wherein the multiple discharge pulse signals include the pulse signal of the first core wire of the power distribution cable, the pulse signal of the first grounding wire of the power distribution cable, the pulse signal of the last core wire of the power distribution cable, and the pulse signal of the last grounding wire of the power distribution cable; the first determination module 704, connected to the acquisition module 702, is used to determine multiple signal band sets corresponding to the multiple discharge pulse signals, wherein each set of multiple signal bands includes at least one signal band of the corresponding discharge pulse signal, and each set of multiple signal bands corresponds to a different signal band category; the second determination module 706, connected to the first determination module 704, is used to determine the signal polarity corresponding to the multiple discharge pulse signals based on the multiple signal band sets corresponding to the multiple discharge pulse signals, wherein the corresponding signal polarity indicates the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value; the third determination module 708, connected to the second determination module 706, is used to determine the target discharge position corresponding to the power distribution cable based on the signal polarity corresponding to the multiple discharge pulse signals.

[0238] It should be noted here that the above-mentioned acquisition module 702, first determination module 704, second determination module 706 and third determination module 708 correspond to steps S102 to S108 in the method for determining the discharge location of power distribution cables. The multiple modules and the corresponding steps implement the same instances and application scenarios, but are not limited to the content disclosed in the above embodiment 1.

[0239] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0240] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0241] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0242] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0243] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0244] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0245] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the discharge location of a power distribution cable, characterized in that, include: Acquire multiple discharge pulse signals of the power distribution cable, wherein the multiple discharge pulse signals include the pulse signal of the first end core wire of the power distribution cable, the pulse signal of the first end grounding wire of the power distribution cable, the pulse signal of the last end core wire of the power distribution cable, and the pulse signal of the last end grounding wire of the power distribution cable; Determine multiple signal band sets corresponding to the multiple discharge pulse signals, wherein each of the multiple signal band sets includes at least one signal band of the corresponding discharge pulse signal, and each of the multiple signal band sets corresponds to a different signal band category; Based on the multiple signal band sets corresponding to the multiple discharge pulse signals, the signal polarity corresponding to the multiple discharge pulse signals is determined, wherein the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value; Based on the signal polarity corresponding to the plurality of discharge pulse signals, the target discharge position corresponding to the power distribution cable is determined; The step of determining the signal polarity corresponding to each of the plurality of discharge pulse signals based on the plurality of signal band sets corresponding to each of the plurality of discharge pulse signals includes: determining the signal polarity corresponding to the target discharge pulse signal based on the target signal band set corresponding to any one of the plurality of discharge pulse signals in the following manner: when the target signal band set includes multiple signal bands, superimposing a predetermined number of signal bands in the plurality of signal bands and taking the average to fit an array of multiple signal bands corresponding to the target discharge pulse signal; determining the peak value and peak value threshold corresponding to each of the array of multiple signal bands; determining the signal polarity corresponding to the target discharge pulse signal based on the peak value threshold and the peak value corresponding to each of the array of multiple signal bands; and obtaining the signal polarity corresponding to each of the other discharge pulse signals in the plurality of discharge pulse signals besides the target discharge pulse signal by using the same method as obtaining the signal polarity corresponding to the target discharge pulse signal. The step of determining the set of multiple signal bands corresponding to the multiple discharge pulse signals includes: determining the signal characteristic parameters corresponding to the multiple discharge pulse signals, wherein the signal characteristic parameters include equivalent duration, equivalent bandwidth, and signal amplitude ratio; and performing a clustering operation on the multiple signal bands included in the multiple discharge pulse signals based on the signal characteristic parameters corresponding to the multiple discharge pulse signals to obtain the set of multiple signal bands corresponding to the multiple discharge pulse signals.

2. The method according to claim 1, characterized in that, The step of determining the signal polarity corresponding to the target discharge pulse signal based on the peak threshold and the peak values ​​corresponding to the plurality of signal band arrays includes: For any target signal band array in the plurality of signal band arrays, the peak value of the corresponding target signal band is compared with the peak value threshold one by one according to the execution order of the plurality of target signal bands in the target signal band array to obtain the waveform comparison result corresponding to the corresponding target signal band, until the waveform comparison result is that the peak value of the corresponding target signal band is greater than or equal to the peak value threshold, and the first wave corresponding to the target signal band array is obtained; The method of obtaining the first wave corresponding to the target signal band array is used to obtain the first wave corresponding to the other signal band arrays besides the target signal band array in the plurality of signal band arrays; Based on the first wave corresponding to each of the multiple signal band arrays, the signal polarity corresponding to the target discharge pulse signal is determined.

3. The method according to claim 1, characterized in that, The step involves clustering the signal bands included in the plurality of discharge pulse signals according to the signal characteristic parameters corresponding to the plurality of discharge pulse signals, to obtain a set of signal bands corresponding to the plurality of discharge pulse signals, including: For any target discharge pulse signal among the plurality of discharge pulse signals, determine the proximity index between any two signal bands among the plurality of signal bands, wherein the proximity index represents the degree of proximity between any two signal bands; Based on the proximity index between any two signal bands among the plurality of signal bands, a set of neighboring bands corresponding to each of the plurality of signal bands is determined, wherein the corresponding set of neighboring bands includes at least one neighboring band, and the neighboring band is another signal band whose proximity index with the corresponding signal band is greater than a proximity threshold. Based on the neighboring band sets corresponding to the plurality of signal bands respectively, mutually adjacent bands corresponding to the plurality of signal bands are determined, wherein the mutually adjacent bands are signal bands that are adjacent to the corresponding signal bands; Based on the neighboring bands corresponding to the plurality of signal bands, determine the distribution density of the neighboring bands corresponding to the plurality of signal bands; Based on the distribution density of neighboring bands corresponding to the multiple signal bands, a set of multiple signal bands corresponding to the target discharge pulse signal is determined; By obtaining a set of multiple signal bands corresponding to the target discharge pulse signal, a set of multiple signal bands corresponding to the other discharge pulse signals besides the target discharge pulse signal can be obtained.

4. The method according to claim 1, characterized in that, Determining the signal amplitude ratio corresponding to each of the plurality of discharge pulse signals includes: Determine the first amplitude ratio between the first-end core wire pulse signal and the last-end core wire pulse signal; Determine the second amplitude ratio between the first-end grounding wire pulse signal and the last-end grounding wire pulse signal; Determine the third amplitude ratio between the pulse signal of the first-end core wire and the pulse signal of the first-end ground wire; Determine the fourth amplitude ratio between the end core wire pulse signal and the end ground wire pulse signal; Based on the first amplitude ratio, the second amplitude ratio, the third amplitude ratio, and the fourth amplitude ratio, the signal amplitude ratio corresponding to the plurality of discharge pulse signals is determined respectively.

5. The method according to claim 1, characterized in that, The acquisition of multiple discharge pulse signals from the power distribution cable includes: Collect multiple initial pulse signals corresponding to the power distribution cable; Multiple signal pairs are determined from the plurality of initial pulse signals; Waveform matching is performed on the first pulse signal and the second pulse signal included in any of the plurality of signal pairs to obtain a matching result corresponding to the target signal pair. The target signal pair includes the first pulse signal and the second pulse signal, which are respectively collected from different locations of the power distribution cable. By obtaining the matching results corresponding to the target signal pair, the matching results corresponding to other signal pairs besides the target signal pair are obtained respectively; Based on the matching results corresponding to the multiple signal pairs, the multiple discharge pulse signals are determined from the multiple initial pulse signals.

6. The method according to claim 5, characterized in that, The step of performing waveform matching between the first pulse signal and the second pulse signal of any target signal pair among the plurality of signal pairs to obtain a matching result corresponding to the target signal pair includes: For any one of the multiple first signal bands included in the first pulse signal, determine the band matching degree between the target first signal band and the multiple second signal bands included in the second pulse signal, and obtain multiple band matching degrees corresponding to the target first signal band; By obtaining multiple band matching degrees corresponding to the target first signal band, multiple band matching degrees corresponding to other first signal bands besides the target first signal band are obtained respectively; Based on the band matching degrees corresponding to the plurality of first signal bands, a matching result corresponding to the target signal pair is obtained.

7. The method according to any one of claims 1 to 6, characterized in that, Determining the target discharge location corresponding to the power distribution cable based on the signal polarity corresponding to the plurality of discharge pulse signals includes: Determine the first comparison result between the signal polarity of the first core wire pulse signal and the signal polarity of the last core wire pulse signal; Based on the first comparison result, the initial discharge position corresponding to the power distribution cable is determined; Determine the second comparison result between the signal polarity of the first-end grounding wire pulse signal and the signal polarity of the last-end grounding wire pulse signal; Based on the second comparison result, the initial discharge position is verified to obtain the discharge position corresponding to the power distribution cable.

8. A device for determining the discharge position of a power distribution cable, characterized in that, include: The acquisition module is used to acquire multiple discharge pulse signals of the power distribution cable, wherein the multiple discharge pulse signals include the pulse signal of the first end core wire of the power distribution cable, the pulse signal of the first end grounding wire of the power distribution cable, the pulse signal of the last end core wire of the power distribution cable, and the pulse signal of the last end grounding wire of the power distribution cable; The first determining module is used to determine a plurality of signal band sets corresponding to the plurality of discharge pulse signals, wherein the plurality of corresponding signal band sets each include at least one signal band of the corresponding discharge pulse signal, and the plurality of corresponding signal band sets each correspond to different signal band categories. The second determining module is used to determine the signal polarity corresponding to the plurality of discharge pulse signals based on the plurality of signal band sets corresponding to the plurality of discharge pulse signals respectively, wherein the corresponding signal polarity represents the positive or negative state of the signal value of the corresponding discharge pulse signal at a predetermined time relative to a predetermined reference value. The third determining module is used to determine the target discharge position corresponding to the power distribution cable based on the signal polarity corresponding to the plurality of discharge pulse signals respectively; The second determining module is further configured to: determine the signal polarity corresponding to the target discharge pulse signal based on the target signal band set corresponding to any one of the plurality of discharge pulse signals in the following manner: when the target signal band set includes multiple signal bands, superimpose a predetermined number of signal bands in the plurality of signal bands and take the average to fit an array of multiple signal bands corresponding to the target discharge pulse signal; determine the peak value and peak value threshold corresponding to the array of multiple signal bands respectively; determine the signal polarity corresponding to the target discharge pulse signal based on the peak value threshold and the peak value corresponding to the array of multiple signal bands respectively; and obtain the signal polarity corresponding to the other discharge pulse signals besides the target discharge pulse signal in the plurality of discharge pulse signals by using the same method as obtaining the signal polarity corresponding to the target discharge pulse signal. The first determining module is further configured to: determine signal characteristic parameters corresponding to the plurality of discharge pulse signals respectively, wherein the signal characteristic parameters include equivalent duration, equivalent bandwidth, and signal amplitude ratio; and perform clustering operation on the plurality of signal bands included in the plurality of discharge pulse signals respectively based on the signal characteristic parameters corresponding to the plurality of discharge pulse signals respectively, to obtain a plurality of signal band sets corresponding to the plurality of discharge pulse signals respectively.

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