Cable partial discharge detection method and device, and nonvolatile storage medium

Abstract

The invention discloses a cable partial discharge detection method and device and a nonvolatile storage medium. The method comprises the following steps: acquiring a plurality of voltage values of a target cable collected in a current sampling period, the plurality of voltage values corresponding to different sampling moments; according to the multiple voltage values, multiple voltage difference values are determined, and the voltage difference values are the difference values between the voltage values collected at the two adjacent sampling moments; clustering the plurality of voltage difference values to obtain characteristic voltage difference values corresponding to a plurality of clustering categories; according to the characteristic voltage difference values corresponding to the plurality of clustering categories, obtaining an initial voltage and a final voltage of partial discharge generated by the target cable; and determining the loss degree of the target cable according to the initial voltage and the final voltage. The technical problem that cable partial discharge cannot be effectively and rapidly detected is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a cable partial discharge detection method, device, and non-volatile storage medium. Background Art

[0002] At present, power cables are widely used in power systems for power transmission and equipment connection. However, with the long-term operation of power cables, their insulation reliability is also declining. In severe cases, partial discharge in power cables can cause cable breakdown, thus causing serious accidents in the power grid. Therefore, it is particularly important to detect partial discharge and damage to power cables. Rapid and accurate testing of the insulation performance of power cables and timely discovery and resolution of potential safety hazards are of great practical significance for the safe operation of the power grid.

[0003] The traditional power cable partial discharge test system can only collect the partial discharge signal of the power cable, but cannot process and analyze it well, let alone analyze its partial discharge situation.

[0004] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0005] The embodiments of the present invention provide a cable partial discharge detection method, device, and non-volatile storage medium to at least solve the technical problem that cable partial discharge cannot be effectively and quickly detected.

[0006] According to one aspect of an embodiment of the present invention, a cable partial discharge detection method is provided, comprising: obtaining multiple voltage values ​​of a target cable collected during a current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments; determining multiple voltage difference values ​​based on the multiple voltage values, wherein the voltage difference value is the difference between voltage values ​​collected at two adjacent sampling moments; clustering the multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories; obtaining a starting voltage and an ending voltage of partial discharge generated in the target cable based on the characteristic voltage difference values ​​corresponding to the multiple clustering categories; and determining the degree of loss of the target cable based on the starting voltage and the ending voltage.

[0007] Optionally, multiple voltage values ​​of the target cable collected during the current sampling period are obtained, wherein the multiple voltage values ​​correspond to different sampling moments, including: obtaining multiple local discharge phase distribution spectra collected during the current sampling period, wherein the multiple local discharge phase distribution spectra correspond to different sampling moments; obtaining multiple discharge phases based on the multiple local discharge phase distribution spectra; obtaining multiple voltage values ​​based on the multiple discharge phases, wherein the multiple discharge phases correspond one-to-one to the multiple voltage values.

[0008] Optionally, multiple voltage difference values ​​are clustered to obtain characteristic voltage difference values ​​corresponding to multiple cluster categories, including: determining multiple initial cluster centers, wherein the multiple initial cluster centers correspond one-to-one to the multiple cluster categories; classifying the multiple voltage difference values ​​based on the distances from the multiple voltage difference values ​​to each of the multiple initial cluster centers, to obtain multiple cluster groups, wherein the multiple cluster groups correspond one-to-one to the multiple initial cluster centers; updating the multiple initial cluster centers according to the voltage difference values ​​respectively included in the multiple cluster groups, to obtain multiple updated cluster centers; using the multiple updated cluster centers as new multiple initial cluster centers, and repeating the above operations until a predetermined termination condition is reached; determining the characteristic voltage difference values ​​corresponding to the multiple cluster categories based on the multiple cluster groups obtained when the predetermined termination condition is reached, wherein the multiple cluster groups correspond one-to-one to the multiple cluster categories.

[0009] Optionally, the loss degree of the target cable is determined based on the starting voltage and the ending voltage, including: determining the number of partial discharges generated by the target cable in the current sampling period based on the starting voltage and the ending voltage; determining the loss degree of the target cable based on the starting voltage, the ending voltage, and the number of partial discharges.

[0010] Optionally, the starting voltage is proportional to the loss degree of the target cable; the ending voltage is inversely proportional to the loss degree of the target cable; and the number of partial discharges is proportional to the loss degree of the target cable.

[0011] Optionally, the loss degree of the target cable is determined according to the starting voltage, the ending voltage, and the number of partial discharges, including: determining a first loss score of the target cable based on the starting voltage; determining a second loss score of the target cable based on the ending voltage; determining a third loss score of the target cable based on the number of partial discharges; obtaining a comprehensive loss score of the target cable based on the first loss score, the second loss score, and the third loss score; and determining the loss degree of the target cable based on the comprehensive loss score.

[0012] Optionally, based on the first loss score, the second loss score, and the third loss score, a comprehensive loss score of the target cable is obtained, including: determining a first weight corresponding to the starting voltage, a second weight corresponding to the ending voltage, and a third weight corresponding to the number of partial discharges; based on the first loss score, the second loss score, the third loss score, the first weight, the second weight and the third weight, weighted calculation is performed to obtain a comprehensive loss score.

[0013] According to another aspect of an embodiment of the present invention, there is provided a cable partial discharge detection device, comprising: a first acquisition module, for acquiring multiple voltage values ​​of a target cable collected during a current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments; a first determination module, for determining multiple voltage difference values ​​based on the multiple voltage values, wherein the voltage difference value is the difference between voltage values ​​collected at two adjacent sampling moments; a first clustering module, for clustering the multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories; a second determination module, for obtaining a start voltage and an end voltage of partial discharge generated in the target cable based on the characteristic voltage difference values ​​corresponding to the multiple clustering categories; and a third determination module, for determining the degree of loss of the target cable based on the start voltage and the end voltage.

[0014] According to another aspect of an embodiment of the present invention, a non-volatile storage medium is provided. The non-volatile storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing any one of the cable partial discharge detection methods.

[0015] According to another aspect of an embodiment of the present invention, there is provided an electronic device, comprising: one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement any one of the cable partial discharge detection methods.

[0016] In an embodiment of the present invention, multiple voltage values ​​of a target cable collected during a current sampling period are obtained, wherein the multiple voltage values ​​correspond to different sampling moments; multiple voltage difference values ​​are determined based on the multiple voltage values, wherein the voltage difference value is the difference between voltage values ​​collected at two adjacent sampling moments; the multiple voltage difference values ​​are clustered to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories; the starting voltage and the ending voltage of local discharge generated in the target cable are obtained based on the characteristic voltage difference values ​​corresponding to the multiple clustering categories; the loss degree of the target cable is determined based on the starting voltage and the ending voltage, thereby solving the technical problem that local discharge of the cable cannot be effectively and quickly detected, achieving the purpose of improving the detection efficiency and detection accuracy of local discharge phenomenon of power cables, and further achieving the technical effect of reducing the safety risks existing in the operation of power cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of a cable partial discharge detection method provided according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of an optional cable partial discharge detection method provided according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of a cable partial discharge detection device provided according to an embodiment of the present invention;

[0021] Figure 4 is a schematic diagram of an electronic device provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0025] Manhattan distance: refers to the sum of the absolute differences in the horizontal and vertical coordinates between two points on a two-dimensional plane. In other words, Manhattan distance is the distance along the line segments of the grid, not the straight line. Its name comes from the urban planning of Manhattan, New York. Manhattan distance is similar to the distance required to walk on the roads in Manhattan, which requires moving horizontally first and then vertically or vice versa. In n-dimensional space, Manhattan distance can be expressed as:

[0026] D=|x 1 -y 1 |+|x 2 -y 2 |+...+|x n -yn |, Manhattan distance is often used in computer science and data analysis, especially in the field of machine learning for clustering algorithms and image similarity comparison.

[0027] According to an embodiment of the present invention, a method embodiment for detecting partial discharge of a cable is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0028] Figure 1 is a flow chart of a cable partial discharge detection method according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0029] Step S102, obtaining multiple voltage values ​​of the target cable collected during the current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments;

[0030] In this step, the current sampling period can be a sampling cycle. A certain position of the cable may produce multiple partial discharge phenomena within a sampling cycle, which may cause damage to the cable insulation layer and affect the service life of the cable. In real life, the cycle can be one year or one month, etc. In the case of an experiment, the length of the cycle can be selected according to the needs of the experiment, which can be a quarter of an hour, one hour, etc. The position is used as a sampling point, and within a determined sampling cycle, the voltage values ​​corresponding to the multiple partial discharges of the tested cable at multiple sampling moments are collected. These voltage values ​​are crucial for detecting the state and performance of the cable, which can help to find problems in time and deal with them to ensure the normal operation of the cable system.

[0031] In an optional embodiment, multiple voltage values ​​of the target cable collected during the current sampling period are obtained, wherein the multiple voltage values ​​correspond to different sampling moments, including: obtaining multiple local discharge phase distribution spectra collected during the current sampling period, wherein the multiple local discharge phase distribution spectra correspond to different sampling moments; obtaining multiple discharge phases based on the multiple local discharge phase distribution spectra; obtaining multiple voltage values ​​based on the multiple discharge phases, wherein the multiple discharge phases correspond one-to-one to the multiple voltage values.

[0032] Optionally, the voltage value generated by partial discharge is usually a relatively low value, generally between tens of volts and hundreds of volts, or even lower. Since this voltage value is very weak and easily interfered with, it cannot be directly measured when obtaining the voltage values ​​corresponding to multiple partial discharges of the cable under test. In addition, partial discharges usually occur in local areas of high-voltage equipment or insulating materials, which makes it more difficult to directly measure the voltage value. In order to obtain the voltage value generated by partial discharge, the following method can be used but is not limited to: install a high-frequency current sensor on the cable under test, use the sensor to obtain the signal generated by each partial discharge, generate a corresponding phase distribution spectrum for the signal generated by each partial discharge, and the distribution of the discharge phase φ and the effective value of the voltage U can be observed from the phase distribution spectrum. 0 According to the sinusoidal AC voltage formula, the voltage value corresponding to each partial discharge can be obtained.

[0033] Step S104, determining a plurality of voltage difference values ​​according to the plurality of voltage values, wherein the voltage difference value is a difference between voltage values ​​respectively collected at two adjacent sampling moments;

[0034] In this step, according to the time sequence of the sampling of multiple voltage values, the difference between the voltage values ​​corresponding to two adjacent sampling moments is calculated in sequence to obtain a set of voltage difference values. These voltage difference values ​​can be calculated by subtracting the voltage value of the previous sampling point from the voltage value of the next sampling point, or by subtracting the voltage value of the next sampling point from the voltage value of the previous sampling point, and then all the voltage difference values ​​are aggregated together to form a data set.

[0035] Step S106, clustering the multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to the multiple clustering categories;

[0036] In this step, the data set of multiple voltage difference values ​​is converted into statistical charts, such as histograms, line charts, etc. It can be observed that the data in the data set have some similar features. Clustering multiple voltage difference values ​​means grouping these voltage difference values ​​according to the similarities between them. Through the clustering algorithm, these voltage difference values ​​can be divided into multiple categories, each category representing a group of voltage difference values ​​with similar characteristics. After obtaining these clustering categories, the data contained in each category can be analyzed to find the characteristic voltage difference values ​​in each clustering category. This can provide a clearer understanding of the differences and similarities between different categories, which is helpful for further data analysis and mining.

[0037] In an optional embodiment, a plurality of voltage difference values ​​are clustered to obtain characteristic voltage difference values ​​corresponding to a plurality of cluster categories, including: determining a plurality of initial cluster centers, wherein the plurality of initial cluster centers correspond one-to-one to the plurality of cluster categories; classifying the plurality of voltage difference values ​​based on the distances from the plurality of voltage difference values ​​to each of the plurality of initial cluster centers, to obtain a plurality of cluster groups, wherein the plurality of cluster groups correspond one-to-one to the plurality of initial cluster centers; updating the plurality of initial cluster centers according to the voltage difference values ​​respectively included in the plurality of cluster groups, to obtain a plurality of updated cluster centers; using the plurality of updated cluster centers as the new plurality of initial cluster centers, and repeating the above operation until a predetermined termination condition is reached; determining the characteristic voltage difference values ​​corresponding to the plurality of cluster categories based on the plurality of cluster groups obtained when the predetermined termination condition is reached, wherein the plurality of cluster groups correspond one-to-one to the plurality of cluster categories.

[0038] Optionally, the multiple voltage difference values ​​are represented in the form of a histogram, and it can be observed that the multiple voltage difference values ​​can be divided into multiple groups according to the magnitude of the values, such as Figure 2 As shown, multiple voltage difference values ​​can be divided into four groups, and the initial cluster centers are determined for each of the four groups. The methods for determining the initial cluster centers include but are not limited to: (1) Random selection, that is, randomly selecting several samples in the data set as the initial cluster centers. (2) K-means++ algorithm: The K-means++ algorithm is an improved method for selecting the initial cluster centers. It selects the initial cluster centers through a certain probability distribution so that the distance between the initial cluster centers is as far as possible, thereby improving the stability of the clustering results. (3) Uniformly distributed sampling, uniformly sampling multiple samples from the sample space as the initial cluster centers. The initial cluster centers can be determined by, but are not limited to, the "uniformly distributed sampling" method, and the total number of multiple initial cluster centers can be set according to actual needs. For example, four values ​​are uniformly selected as the initial cluster centers. After determining the four initial cluster centers, the Manhattan distances between the four initial centers and the voltage difference are calculated iteratively, the voltage difference closest to the initial center is assigned to the corresponding group, and a new cluster center is calculated until the cluster center and the group do not change after many iterations. Finally, four groups and four cluster centers are obtained. The final four groups are used as cluster categories, and the final four cluster centers are used as characteristic voltage differences.

[0039] Step S108, obtaining the starting voltage and ending voltage of partial discharge in the target cable according to the characteristic voltage differences corresponding to the multiple clustering categories;

[0040] Optionally, the starting voltage of partial discharge refers to the voltage value required for the material to begin partial discharge under specific conditions. The starting voltage of partial discharge reflects the voltage resistance performance of the material and can also be used to evaluate the health of the insulation system. The size of the starting voltage can be used to judge the quality of the insulation system. If the starting voltage is low, it means that the insulation system is of good quality and has high insulation performance; otherwise, there may be problems such as insulation aging, contamination or damage. The termination voltage of partial discharge means that when partial discharge occurs, when the voltage drops to a certain level, the discharge phenomenon will stop and disappear. After clustering, four characteristic voltage differences are obtained. The average of the two characteristic voltage differences with the largest absolute values ​​among the four characteristic voltage differences is calculated to obtain dV 2 , calculate the average value of the two characteristic voltage differences with the smallest absolute values ​​among the four characteristic voltage differences, and get dV 1 , through dV 2 and dV 1 Calculate the partial discharge starting voltage V I And the termination voltage of partial discharge V X , the calculation formula is as follows.

[0041]

[0042] Step S110, determining the loss degree of the target cable according to the starting voltage and the ending voltage.

[0043] Optionally, partial discharge refers to the phenomenon of electric spark discharge that occurs locally in the insulating material. Its starting voltage and ending voltage are important parameters for judging the discharge difficulty of the tested cable. The starting voltage refers to the voltage value at which partial discharge begins to appear in the cable, which reflects the withstand voltage of the cable insulation material. The ending voltage refers to the voltage value at which partial discharge stops, which reflects the recovery ability of the cable insulation material. If the starting voltage of the tested cable is low, it means that its insulation material is more prone to partial discharge and the target cable has a greater loss degree. If the ending voltage is high, it means that the insulation material has a better recovery ability and the target cable has a smaller loss degree.

[0044] In an optional embodiment, the loss degree of the target cable is determined based on the starting voltage and the ending voltage, including: determining the number of local discharges generated by the target cable in the current sampling period based on the starting voltage and the ending voltage; determining the loss degree of the target cable based on the starting voltage, the ending voltage, and the number of local discharges.

[0045] Optionally, according to the effective voltage value U of the partial discharge 0 、Partial discharge starting voltage V I , Partial discharge termination voltage V X Calculate the number of partial discharges per cycle n pc, get the number of partial discharges per cycle, the number of partial discharges per cycle n pc The calculation formula is as follows.

[0046]

[0047] In an optional embodiment, the starting voltage is proportional to the loss degree of the target cable; the ending voltage is inversely proportional to the loss degree of the target cable; and the number of partial discharges is proportional to the loss degree of the target cable.

[0048] Optionally, according to the partial discharge starting voltage V I And the termination voltage of partial discharge V X The size of the partial discharge per cycle is used to analyze the damage of the tested cable. The starting voltage V I The loss of the tested cable is proportional to the starting voltage V of the partial discharge. I The larger the value, the greater the loss of the tested cable, and the starting voltage V I The smaller it is, the smaller the loss of the tested cable. The termination voltage V of partial discharge X It is inversely proportional to the loss of the measured cable, that is, the termination voltage of partial discharge V X The higher the voltage, the smaller the loss of the tested cable. X The lower it is, the greater the loss of the tested cable. The number of partial discharges is proportional to the loss of the tested cable, that is, the more partial discharges there are, the greater the loss of the tested cable, and the fewer partial discharges there are, the smaller the loss of the tested cable.

[0049] In an optional embodiment, the loss degree of the target cable is determined according to the starting voltage, the ending voltage, and the number of partial discharges, including: determining a first loss score of the target cable based on the starting voltage; determining a second loss score of the target cable based on the ending voltage; determining a third loss score of the target cable based on the number of partial discharges; obtaining a comprehensive loss score of the target cable based on the first loss score, the second loss score, and the third loss score; and determining the loss degree of the target cable based on the comprehensive loss score.

[0050] Optionally, the correspondence between multiple starting voltage ranges and cable loss scores can be pre-set. When the starting voltage of the tested cable is determined, the target starting voltage range to which the starting voltage of the tested cable belongs is determined from the multiple starting voltage ranges; the cable loss score corresponding to the target starting voltage range is determined as the first loss score of the tested cable. The correspondence between multiple termination voltage ranges and cable loss scores can be pre-set. When the termination voltage of the tested cable is determined, the target termination voltage range to which the termination voltage of the tested cable belongs is determined from the multiple termination voltage ranges; the cable loss score corresponding to the target termination voltage range is determined as the second loss score of the tested cable. The correspondence between multiple partial discharge number ranges and cable loss scores can be pre-set. When the partial discharge number of the tested cable is determined, the target partial discharge number range to which the partial discharge number of the tested cable belongs is determined from the multiple partial discharge number ranges; the cable loss score corresponding to the target partial discharge number range is determined as the third loss score of the tested cable. A comprehensive loss score is obtained based on the first loss score, the second loss score, and the third loss score. Regarding determining the loss degree of the tested cable based on the comprehensive loss score: the comprehensive loss score can be directly used as the loss degree of the target cable; or the correspondence between multiple cable loss score ranges and cable loss levels can be pre-set. When the cable loss score range to which the comprehensive loss score belongs is known, the corresponding cable loss level is also determined, and the cable loss level can characterize the loss degree of the target cable.

[0051] Optionally, the comprehensive loss score may be obtained by averaging the first loss score, the second loss score, and the third loss score, or by weighted calculation of the first loss score, the second loss score, and the third loss score.

[0052] In an optional embodiment, based on the first loss score, the second loss score, and the third loss score, a comprehensive loss score of the target cable is obtained, including: determining a first weight corresponding to the starting voltage, a second weight corresponding to the ending voltage, and a third weight corresponding to the number of partial discharges; based on the first loss score, the second loss score, the third loss score, the first weight, the second weight, and the third weight, weighted calculation is performed to obtain a comprehensive loss score.

[0053] Optionally, according to the importance of the starting voltage, the ending voltage and the number of partial discharges to the loss degree of the measured cable, the first weight, the second weight and the third weight corresponding to the starting voltage, the ending voltage and the number of partial discharges are set respectively, and the sum of the three weights is 100%. The calculation formula for the comprehensive loss score is: first loss score * first weight + second loss score * second weight + third loss score * second weight = comprehensive loss score. By setting weights for weighted calculation, different importance can be given to the starting voltage, the ending voltage and the number of partial discharges, so that the comprehensive loss score of the target cable is more objective and accurate. The setting of weights can be determined according to actual conditions and needs, and can be set according to expert opinions, historical data, experience, etc., which are not specifically limited here.

[0054] Through the above, multiple voltage values ​​of the target cable collected during the current sampling period are obtained, wherein the multiple voltage values ​​correspond to different sampling moments; multiple voltage difference values ​​are determined based on the multiple voltage values, wherein the voltage difference value is the difference between the voltage values ​​collected at two adjacent sampling moments; multiple voltage difference values ​​are clustered to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories; according to the characteristic voltage difference values ​​corresponding to multiple clustering categories, the starting voltage and ending voltage of partial discharge generated by the target cable are obtained; according to the starting voltage and ending voltage, the loss degree of the target cable is determined. The technical problem that partial discharge of the cable cannot be effectively and quickly detected is solved, and the purpose of improving the detection efficiency and detection accuracy of partial discharge phenomenon of power cables is achieved, thereby achieving the technical effect of reducing the safety risks existing in the operation of power cables.

[0055] Based on the above embodiments and optional embodiments, the present invention proposes an optional implementation mode:

[0056] Step S1, obtaining multiple voltage values ​​of the target cable collected during the current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments, including: obtaining multiple local discharge phase distribution spectra collected during the current sampling period, wherein the multiple local discharge phase distribution spectra correspond to different sampling moments; obtaining multiple discharge phases according to the multiple local discharge phase distribution spectra; obtaining multiple voltage values ​​according to the multiple discharge phases, wherein the multiple discharge phases correspond to the multiple voltage values ​​one by one.

[0057] Optionally, the voltage value generated by partial discharge is usually low and easily interfered, so the voltage value corresponding to multiple partial discharges on the tested cable cannot be directly measured. In addition, partial discharge usually occurs in local areas of high-voltage equipment or insulating materials, and it is difficult to directly measure the voltage value. In order to obtain the voltage value generated by partial discharge, a high-frequency current sensor can be installed on the tested cable, and the sensor can be used to obtain the electrical signal generated by each partial discharge and generate a corresponding phase distribution spectrum. By observing the discharge phase distribution and the maximum value of the voltage in the phase distribution spectrum, the voltage value corresponding to each partial discharge is calculated according to the formula of the sinusoidal AC voltage.

[0058] Step S2, determining a plurality of voltage difference values ​​according to the plurality of voltage values, wherein the voltage difference value is a difference between voltage values ​​respectively collected at two adjacent sampling moments;

[0059] Optionally, in this step, in accordance with the sampling time sequence, the voltage value corresponding to the first sampling point is subtracted from the voltage value corresponding to the second sampling point to obtain a first voltage difference value, the voltage value corresponding to the second sampling point is subtracted from the voltage value corresponding to the third sampling point to obtain a second voltage difference value, and so on, that is, the voltage value corresponding to the Nth sampling point is subtracted from the voltage value corresponding to the N+1th sampling point to obtain the Nth voltage difference value, and all the voltage difference values ​​are gathered together to obtain a data set of voltage differences. The method for obtaining the data set of voltage differences includes but is not limited to this calculation method. For example, the voltage value corresponding to the N+1th sampling point can also be subtracted from the voltage value corresponding to the Nth sampling point to obtain the Nth voltage difference value.

[0060] Step S3, clustering multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories, including: determining multiple initial clustering centers, wherein the multiple initial clustering centers correspond one-to-one to the multiple clustering categories; classifying the multiple voltage difference values ​​based on the distances from the multiple voltage difference values ​​to each of the multiple initial clustering centers, to obtain multiple clustering groups, wherein the multiple clustering groups correspond one-to-one to the multiple initial clustering centers; updating the multiple initial clustering centers according to the voltage difference values ​​respectively included in the multiple clustering groups, to obtain multiple updated clustering centers; using the multiple updated clustering centers as new multiple initial clustering centers, and repeating the above operations until a predetermined termination condition is reached; determining the characteristic voltage difference values ​​corresponding to the multiple clustering categories based on the multiple clustering groups obtained when the predetermined termination condition is reached, wherein the multiple clustering groups correspond one-to-one to the multiple clustering categories.

[0061] Optionally, in the present application, multiple voltage difference values ​​can be divided into four groups according to their size, and a uniform distribution sampling method is used to determine four initial cluster centers, and the voltage difference values ​​with the closest distance are assigned to the corresponding new cluster groups, and the new cluster centers corresponding to the new cluster groups are calculated. Repeat this process until the cluster centers and groups no longer change. Finally, four groups and four cluster centers are obtained, and these four groups are used as cluster categories, and the four cluster centers are used as characteristic voltage difference values.

[0062] Step S4, obtaining the starting voltage and ending voltage of partial discharge in the target cable according to the characteristic voltage differences corresponding to the multiple clustering categories;

[0063] Optionally, four characteristic voltage differences are obtained through clustering, and the average value of the two characteristic voltage differences with the largest absolute values ​​among the four characteristic voltage differences is calculated to obtain dV 2 , calculate the average value of the two characteristic voltage differences with the smallest absolute values ​​among the four characteristic voltage differences, and get dV 1 , through dV 2 and dV 1 Calculate the partial discharge starting voltage V I And the termination voltage of partial discharge V X , the calculation formula is:

[0064]

[0065] Step S5, determining the loss degree of the target cable according to the starting voltage and the ending voltage, including: determining the number of partial discharges generated by the target cable in the current sampling period according to the starting voltage and the ending voltage; determining the loss degree of the target cable according to the starting voltage, the ending voltage, and the number of partial discharges.

[0066] Optionally, according to the effective voltage value U of the partial discharge 0 、Partial discharge starting voltage V I , Partial discharge termination voltage V X Calculate the number of partial discharges per cycle n pc , get the number of partial discharges per cycle, the number of partial discharges per cycle n pc The calculation formula is as follows:

[0067]

[0068] Step S51, determining the loss degree of the target cable according to the starting voltage, the ending voltage, and the number of partial discharges, including: determining a first loss score of the target cable based on the starting voltage; determining a second loss score of the target cable based on the ending voltage; determining a third loss score of the target cable based on the number of partial discharges; obtaining a comprehensive loss score of the target cable based on the first loss score, the second loss score, and the third loss score; and determining the loss degree of the target cable based on the comprehensive loss score.

[0069] Optionally, the correspondence between multiple starting voltage ranges and cable loss scores can be pre-set. When the starting voltage of the tested cable is determined, the target starting voltage range to which the starting voltage of the tested cable belongs is determined from the multiple starting voltage ranges; the cable loss score corresponding to the target starting voltage range is determined as the first loss score of the tested cable. The second loss score and the third loss score are determined respectively using similar methods, and a comprehensive loss score is obtained based on the first loss score, the second loss score, and the third loss score. Regarding determining the loss degree of the tested cable based on the comprehensive loss score: the comprehensive loss score can be directly used as the loss degree of the target cable; the correspondence between multiple cable loss score ranges and cable loss levels can also be pre-set. When the cable loss score range to which the comprehensive loss score belongs is known, the corresponding cable loss level is also determined, and the cable loss level can characterize the loss degree of the target cable. For example, the full score of the comprehensive loss score is 100 points, and the cable loss degree is divided into 5 levels. When the comprehensive loss score is 0-20 points, the cable loss degree is level one; when the comprehensive loss score is 21-40, the cable loss degree is level two; when the comprehensive loss score is 41-60, the cable loss degree is level three; when the comprehensive loss score is 61-80, the cable loss degree is level four; when the comprehensive loss score is 81-100, the cable loss degree is level five.

[0070] Step S52, based on the first loss score, the second loss score, and the third loss score, obtain a comprehensive loss score of the target cable, including: determining a first weight corresponding to the starting voltage, a second weight corresponding to the ending voltage, and a third weight corresponding to the number of partial discharges; based on the first loss score, the second loss score, the third loss score, the first weight, the second weight and the third weight, perform weighted calculation to obtain a comprehensive loss score.

[0071] Optionally, according to the importance of the starting voltage, the ending voltage and the number of partial discharges to the loss degree of the tested cable, the first weight, the second weight and the third weight corresponding to the starting voltage, the ending voltage and the number of partial discharges are set respectively, and the sum of the three weights is 100%. The three loss scores are multiplied by the corresponding weights respectively and the sum is added to obtain a comprehensive loss score.

[0072] The above optional implementation achieves at least the following effects: solves the technical problem that partial discharge of cables cannot be effectively and quickly detected, achieves the purpose of improving the detection efficiency and detection accuracy of partial discharge phenomena in power cables, and thus achieves the technical effect of reducing the safety risks existing in the operation of power cables.

[0073] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0074] In this embodiment, a cable partial discharge detection device is also provided, which is used to implement the above embodiments and preferred implementations, and the descriptions that have been made will not be repeated. As used below, the terms "module" and "device" can implement a combination of software and / or hardware for a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0075] According to an embodiment of the present invention, there is also provided an embodiment of a device for implementing a cable partial discharge detection method. Figure 3 A schematic diagram of a cable partial discharge detection device according to an embodiment of the present invention is shown in FIG. Figure 3 As shown, the above cable partial discharge detection device includes a first acquisition module 31, a first determination module 32, a first clustering module 33, a second determination module 34, and a third determination module 35. The device is described below.

[0076] A first acquisition module 31 is used to acquire multiple voltage values ​​of the target cable collected during the current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments;

[0077] A first determining module 32, connected to the first acquiring module 31, is used to determine a plurality of voltage difference values ​​according to a plurality of voltage values, wherein the voltage difference value is a difference between voltage values ​​respectively collected at two adjacent sampling moments;

[0078] A first clustering module 33, connected to the first determining module 32, is used to cluster the multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to the multiple clustering categories;

[0079] The second determination module 34 is connected to the first clustering module 33 and is used to obtain the starting voltage and the ending voltage of the target cable generating partial discharge according to the characteristic voltage differences corresponding to the multiple clustering categories;

[0080] The third determination module 35 is connected to the second determination module 34 and is used to determine the loss degree of the target cable according to the starting voltage and the ending voltage.

[0081] In a cable partial discharge detection device provided by an embodiment of the present invention, a first acquisition module is set to obtain multiple voltage values ​​of the target cable collected during the current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments; a first determination module is used to determine multiple voltage differences based on the multiple voltage values, wherein the voltage difference is the difference between the voltage values ​​collected at two adjacent sampling moments; a first clustering module is used to cluster the multiple voltage differences to obtain characteristic voltage differences corresponding to multiple clustering categories; a second determination module is used to obtain the starting voltage and ending voltage of the target cable generating partial discharge based on the characteristic voltage differences corresponding to the multiple clustering categories; a third determination module is used to determine the loss degree of the target cable based on the starting voltage and ending voltage. The technical problem that cable partial discharge cannot be effectively and quickly detected is solved, and the purpose of improving the detection efficiency and detection accuracy of the partial discharge phenomenon of the power cable is achieved, thereby achieving the technical effect of reducing the safety risks existing in the operation of the power cable.

[0082] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0083] It should be noted that the first acquisition module 31, the first determination module 32, the first clustering module 33, the second determination module 34, and the third determination module 35 correspond to steps S102 to S110 in the embodiment, and the examples and application scenarios implemented by the modules and the corresponding steps are the same, but are not limited to the contents disclosed in the above embodiments. It should be noted that the modules as part of the device can be run in a computer terminal.

[0084] It should be noted that the optional or preferred implementation of this embodiment can refer to the relevant description in the embodiment, which will not be repeated here.

[0085] The above-mentioned cable partial discharge detection device may also include a processor and a memory. The first acquisition module 31, the first determination module 32, the first clustering module 33, the second determination module 34, the third determination module 35, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions.

[0086] The processor includes a kernel, which retrieves the corresponding program unit from the memory. There can be one or more kernels. The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one storage chip.

[0087] An embodiment of the present invention provides a non-volatile storage medium on which a program is stored. When the program is executed by a processor, a cable partial discharge detection method is implemented.

[0088] like Figure 4 It is shown that an embodiment of the present invention provides an electronic device, the electronic device 10 includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: the memory is used to store a computer program, wherein, when the computer program is executed by the processor, the processor implements the above-mentioned cable partial discharge detection method. The device in this article may be a server, a PC, etc.

[0089] The above sequence of the embodiments of the present invention is for description only and does not represent the superiority or inferiority of the embodiments.

[0090] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0091] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the above modules can be a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, modules or indirect coupling or communication connection of modules, which can be electrical or other forms.

[0092] The modules described above as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0093] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of software functional modules.

[0094] If the above-mentioned integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable non-volatile storage medium. Based on this understanding, the technical solution of the present invention is essentially 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. The computer software product is stored in a non-volatile storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the various embodiments of the present invention. The aforementioned non-volatile storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0095] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A cable partial discharge detection method, characterized in that: include: Acquire multiple voltage values ​​of the target cable collected during the current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments; Determine a plurality of voltage difference values ​​according to the plurality of voltage values, wherein the voltage difference value is a difference between voltage values ​​respectively collected at two adjacent sampling moments; Clustering the multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories respectively; Obtaining a starting voltage and an ending voltage of partial discharge generated by the target cable according to characteristic voltage differences corresponding to the plurality of clustering categories; The loss degree of the target cable is determined according to the starting voltage and the ending voltage.

2. The method according to claim 1, characterized in that The step of obtaining a plurality of voltage values ​​of the target cable collected during the current sampling period, wherein the plurality of voltage values ​​correspond to different sampling moments, includes: Acquire a plurality of partial discharge phase distribution spectra collected during the current sampling period, wherein the plurality of partial discharge phase distribution spectra correspond to different sampling moments; Obtaining multiple discharge phases according to the multiple local discharge phase distribution spectra; The multiple voltage values ​​are obtained according to the multiple discharge phases, wherein the multiple discharge phases correspond to the multiple voltage values ​​one by one.

3. The method according to claim 1, characterized in that The clustering of the multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories respectively includes: Determine a plurality of initial cluster centers, wherein the plurality of initial cluster centers correspond to the plurality of cluster categories one by one; Based on the distances from the multiple voltage difference values ​​to each of the multiple initial cluster centers, the multiple voltage difference values ​​are classified to obtain multiple cluster groups, wherein the multiple cluster groups correspond to the multiple initial cluster centers one by one; according to the voltage difference values ​​respectively included in the multiple cluster groups, the multiple initial cluster centers are updated to obtain multiple updated cluster centers; The updated cluster centers are used as new initial cluster centers, and the above operation is repeated until a predetermined termination condition is reached; Based on the multiple cluster groups obtained when the predetermined termination condition is reached, characteristic voltage difference values ​​respectively corresponding to the multiple cluster categories are determined, wherein the multiple cluster groups correspond to the multiple cluster categories one by one.

4. The method according to claim 1, characterized in that: The step of determining the loss degree of the target cable according to the starting voltage and the ending voltage includes: Determine the number of times the target cable generates partial discharge during the current sampling period according to the starting voltage and the ending voltage; The loss degree of the target cable is determined according to the starting voltage, the ending voltage, and the number of partial discharges.

5. The method according to claim 4, characterized in that The starting voltage is proportional to the loss degree of the target cable; The termination voltage is inversely proportional to the loss level of the target cable; The number of partial discharges is proportional to the loss degree of the target cable.

6. The method according to claim 4, characterized in that The step of determining the loss degree of the target cable according to the starting voltage, the ending voltage, and the number of partial discharges comprises: Determining a first loss score of the target cable based on the starting voltage; determining a second loss score for the target cable based on the termination voltage; Determining a third loss score of the target cable based on the number of partial discharges; Obtaining a comprehensive loss score of the target cable based on the first loss score, the second loss score, and the third loss score; Based on the comprehensive loss score, the loss level of the target cable is determined.

7. The method according to claim 6, characterized in that The step of obtaining a comprehensive loss score of the target cable based on the first loss score, the second loss score, and the third loss score includes: Determine a first weight corresponding to the starting voltage, a second weight corresponding to the ending voltage, and a third weight corresponding to the number of partial discharges; Based on the first loss score, the second loss score, the third loss score, the first weight, the second weight and the third weight, a weighted calculation is performed to obtain the comprehensive loss score.

8. A cable partial discharge detection device, characterized in that: include: A first acquisition module is used to acquire multiple voltage values ​​of the target cable collected during the current sampling period, wherein the multiple voltage values ​​correspond to different sampling moments; A first determining module, configured to determine a plurality of voltage difference values ​​according to the plurality of voltage values, wherein the voltage difference value is a difference between voltage values ​​respectively collected at two adjacent sampling moments; A first clustering module, used for clustering the multiple voltage difference values ​​to obtain characteristic voltage difference values ​​corresponding to multiple clustering categories respectively; A second determination module is used to obtain a starting voltage and an ending voltage of a partial discharge generated in the target cable according to characteristic voltage differences corresponding to the plurality of cluster categories; The third determination module is used to determine the loss degree of the target cable according to the starting voltage and the ending voltage.

9. A non-volatile storage medium, characterized in that: The non-volatile storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the cable partial discharge detection method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: include: One or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the cable partial discharge detection method according to any one of claims 1 to 7.

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