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

Abstract

The application discloses a kind of cable partial discharge detection method, device, nonvolatile storage medium.Therein, the method includes: obtaining the multiple voltage values of target cable collected in current sampling period, wherein multiple voltage values correspond to different sampling time;According to multiple voltage values, determine multiple voltage difference values, wherein voltage difference value is the difference between voltage values collected at two adjacent sampling time respectively;Multiple voltage difference values are clustered, and the characteristic voltage difference value corresponding to multiple clustering categories respectively is obtained;According to the characteristic voltage difference value corresponding to multiple clustering categories respectively, the starting voltage and termination voltage of the partial discharge generated by target cable are obtained;According to starting voltage and termination voltage, the loss degree of target cable is determined.The application solves the technical problem that cable partial discharge cannot be effectively and quickly detected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, in particular to a cable partial discharge detection method and device and a nonvolatile storage medium. BACKGROUND

[0002] At present, power cables are widely used in power systems for power transmission and device connection, but the insulation reliability of power cables is also declining with long-term operation. In the case of serious damage of partial discharge to the insulation of power cables, the cables may be punctured, thereby causing serious accidents of the power grid. Therefore, it is particularly important to detect the partial discharge and damage of power cables. It is of great practical significance to detect the insulation performance of power cables quickly and accurately, and to discover and solve safety hazards in time for the safe operation of the power grid.

[0003] The traditional power cable partial discharge test system can only collect the partial discharge signals of power cables, and cannot well process and analyze the partial discharge signals, and cannot analyze the partial discharge of power cables.

[0004] At present, no effective solution has been proposed for the above problems. SUMMARY

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

[0006] According to an aspect of an embodiment of the present application, a cable partial discharge detection method is provided, including: obtaining a plurality of voltage values of a target cable collected in a current sampling period, wherein the plurality of voltage values correspond to different sampling times; determining a plurality of voltage difference values according to the plurality of voltage values, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling times; clustering the plurality of voltage difference values to obtain feature voltage difference values corresponding to a plurality of clustering categories respectively; obtaining a starting voltage and a termination voltage of the partial discharge of the target cable according to the feature voltage difference values corresponding to the plurality of clustering categories respectively; and determining the damage degree of the target cable according to the starting voltage and the termination voltage.

[0007] Optionally, obtaining the plurality of voltage values of the target cable collected in the current sampling period, wherein the plurality of voltage values correspond to different sampling times, includes: obtaining a plurality of partial discharge phase distribution spectrograms collected in the current sampling period, wherein the plurality of partial discharge phase distribution spectrograms correspond to different sampling times; obtaining a plurality of discharge phases according to the plurality of partial discharge phase distribution spectrograms; and obtaining the plurality of voltage values according to the plurality of discharge phases, wherein the plurality of discharge phases and the plurality of voltage values correspond one-to-one.

[0008] Optionally, the plurality of voltage difference values are clustered to obtain feature voltage difference values corresponding to a plurality of clustering categories, comprising: determining a plurality of initial clustering centers, wherein the plurality of initial clustering centers and the plurality of clustering categories correspond one by one; based on the distance of each initial clustering center in the plurality of initial clustering centers to the plurality of voltage difference values, the plurality of voltage difference values are classified to obtain a plurality of clustering groups, wherein the plurality of clustering groups correspond one by one to the plurality of initial clustering centers; according to the voltage difference values included in the plurality of clustering groups, the plurality of initial clustering centers are updated to obtain a plurality of updated clustering centers; the plurality of updated clustering centers are taken as new plurality of initial clustering centers, and the above operation is repeatedly executed until a predetermined termination condition is reached; based on the plurality of clustering groups obtained when the predetermined termination condition is reached, the feature voltage difference values corresponding to the plurality of clustering categories are determined, wherein the plurality of clustering groups correspond one by one to the plurality of clustering categories.

[0009] Optionally, according to the starting voltage and the ending voltage, the loss degree of the target cable is determined, comprising: according to the starting voltage and the ending voltage, the number of times of local discharge generated by the target cable in the current sampling period is determined; according to the starting voltage, the ending voltage, and the number of times of local discharge, the loss degree of the target cable is determined.

[0010] Optionally, the starting voltage is directly proportional to the loss degree of the target cable; the ending voltage is inversely proportional to the loss degree of the target cable; the number of times of local discharge is directly proportional to the loss degree of the target cable.

[0011] Optionally, according to the starting voltage, the ending voltage, and the number of times of local discharge, the loss degree of the target cable is determined, comprising: based on the starting voltage, a first loss score of the target cable is determined; based on the ending voltage, a second loss score of the target cable is determined; based on the number of times of local discharge, a third loss score of the target cable is determined; 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; based on the comprehensive loss score, the loss degree of the target cable is determined.

[0012] Optionally, based on the first loss score, the second loss score, and the third loss score, the comprehensive loss score of the target cable is obtained, comprising: 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 times of local discharge; 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.

[0013] According to another aspect of the embodiments of the present application, a cable partial discharge detection device is provided, comprising: a first acquisition module configured to acquire a plurality of voltage values of a target cable collected in a current sampling period, wherein the plurality of voltage values correspond to different sampling time points; a first determination module configured to determine a plurality of voltage difference values according to the plurality of voltage values, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling time points; a first clustering module configured to cluster the plurality of voltage difference values to obtain feature voltage difference values corresponding to a plurality of clustering categories respectively; a second determination module configured to obtain a starting voltage and a termination voltage of the partial discharge generated by the target cable according to the feature voltage difference values corresponding to the plurality of clustering categories respectively; and a third determination module configured to determine the loss degree of the target cable according to the starting voltage and the termination voltage.

[0014] According to another aspect of the embodiments of the present application, a non-volatile storage medium is provided, which stores a plurality of instructions adapted to be loaded and executed by a processor to implement any one of the cable partial discharge detection methods.

[0015] According to another aspect of the embodiments of the present application, an electronic device is provided, comprising: one or more processors and a memory configured 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 are caused to implement any one of the cable partial discharge detection methods.

[0016] In the embodiments of the present application, by acquiring a plurality of voltage values of a target cable collected in a current sampling period, wherein the plurality of voltage values correspond to different sampling time points; determining a plurality of voltage difference values according to the plurality of voltage values, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling time points; clustering the plurality of voltage difference values to obtain feature voltage difference values corresponding to a plurality of clustering categories respectively; obtaining a starting voltage and a termination voltage of the partial discharge generated by the target cable according to the feature voltage difference values corresponding to the plurality of clustering categories respectively; and determining the loss degree of the target cable according to the starting voltage and the termination voltage, the technical problem that the cable partial discharge cannot be effectively and quickly detected is solved, the purpose of improving the detection efficiency and detection accuracy of the power cable partial discharge phenomenon is achieved, and the technical effect of reducing the safety risk existing in the operation of the power cable is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are included to provide a further understanding of the present application and constitute a part of this application, illustrate certain illustrative embodiments of the present application and together with the description serve to explain the present application. In the drawings:

[0018] Figure 1 is a flowchart of a cable partial discharge detection method provided according to the embodiments of the present application;

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

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

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

[0022] In order to make the personnel in the art better understand the present application scheme, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0023] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in other than the order illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to include only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0024] For the convenience of description, part of the nouns or terms related to the embodiments of the present application are described as follows:

[0025] Manhattan distance: refers to the sum of the absolute difference of the horizontal and vertical coordinates between two points in a two-dimensional plane. That is, the Manhattan distance is the distance along the grid segment, rather than the straight line. Its name comes from the city planning of Manhattan, New York. Manhattan distance is similar to the distance required to walk on the roads of Manhattan, which needs to move horizontally first and then vertically or vice versa. In n-dimensional space, the Manhattan distance can be expressed as:

[0026] D = |x1-y1| + |x2-y2| +... + |x n n ​The Manhattan distance is often used in computer science and data analysis, particularly in the field of machine learning for clustering algorithms and image similarity comparisons.

[0027] According to an embodiment of the present application, a method 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 herein can be executed in an order different from that shown.

[0028] Figure 1 is a flowchart of a method for detecting partial discharge of a cable according to an embodiment of the present application, as shown in Figure 1 The method comprises the following steps:

[0029] In step S102, a plurality of voltage values of the target cable collected in the current sampling period are obtained, wherein the plurality of voltage values correspond to different sampling times.

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

[0031] In an alternative embodiment, obtaining a plurality of voltage values of the target cable collected in the current sampling period, wherein the plurality of voltage values correspond to different sampling times, comprises: obtaining a plurality of partial discharge phase distribution spectrograms collected in the current sampling period, wherein the plurality of partial discharge phase distribution spectrograms correspond to different sampling times; obtaining a plurality of discharge phases according to the plurality of partial discharge phase distribution spectrograms; obtaining a plurality of voltage values according to the plurality of discharge phases, wherein the plurality of discharge phases and the plurality of voltage values correspond one-to-one.

[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. Because this voltage value is very weak and is easily disturbed, when obtaining the voltage values corresponding to multiple partial discharges of the measured cable respectively, it cannot be directly measured. In addition, partial discharge usually occurs in a local area 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: installing a high-frequency current sensor on the measured cable, using the sensor to obtain the signal generated by each partial discharge, generating a corresponding phase distribution spectrum from the signal generated by each partial discharge, from which the distribution of discharge phase distribution φ and the effective value of voltage U0 can be observed, and according to the formula of sinusoidal alternating voltage, the voltage value corresponding to each partial discharge can be obtained.

[0033] In step S104, a plurality of voltage difference values are determined according to the plurality of voltage values, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling time points;

[0034] In this step, the difference between the voltage values corresponding to two adjacent sampling time points is calculated in the order of the time sequence of the plurality of voltage values, and a set of voltage difference values is obtained. 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. Then all the voltage difference values are collected together to form a data set.

[0035] In step S106, a plurality of clustering categories corresponding to characteristic voltage difference values are obtained by clustering the plurality of voltage difference values.

[0036] In this step, the data set of the plurality of voltage difference values is converted into a statistical chart, such as a histogram, a line chart, etc. It can be observed that there are some similar features in the data set. Clustering the plurality of voltage difference values means grouping these voltage difference values according to their similarity. Through clustering algorithms, these voltage difference values can be divided into multiple categories, each category representing a group of voltage difference values with similar features. 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 more clearly understand the differences and similarities between different categories, which is helpful for further data analysis and mining.

[0037] In an optional embodiment, 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.

[0038] Optionally, 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 size 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 initial cluster centers. It selects 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) Uniform distribution sampling, uniformly sampling multiple samples from the sample space as initial cluster centers. The initial cluster centers can be determined by, but are not limited to, the "uniform distribution 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 initial cluster centers. After determining the four initial cluster centers, the Manhattan distance between the four initial centers and the voltage difference is calculated iteratively, the voltage difference closest to the initial center is assigned to the corresponding group, and the new cluster center is calculated until the cluster center and the group no longer 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 cluster categories;

[0040] Optionally, the starting voltage of partial discharge refers to the voltage value required for the material to start partial discharge phenomenon under certain conditions. The starting voltage of partial discharge reflects the voltage resistance performance of the material, and can also be used to evaluate the health status 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 refers to the voltage at which the discharge phenomenon stops and disappears when the voltage decreases to a certain extent during partial discharge. Four characteristic voltage differences are obtained through clustering. The average value of the two characteristic voltage differences with the largest absolute value among the four characteristic voltage differences is obtained as dV2. The average value of the two characteristic voltage differences with the smallest absolute value among the four characteristic voltage differences is obtained as dV1. The starting voltage V I and the termination voltage V X of partial discharge are calculated by dV2 and dV1. The calculation formula is as follows.

[0041]

[0042] In step S110, the loss degree of the target cable is determined according to the starting voltage and the termination voltage.

[0043] Optionally, partial discharge refers to the electric spark discharge phenomenon occurring locally in the insulation material. Its starting voltage and termination voltage are important parameters for judging the difficulty of discharging of the measured cable. The starting voltage refers to the voltage value at which partial discharge begins to occur in the cable, which reflects the voltage resistance capability of the cable insulation material. The termination voltage refers to the voltage value at which partial discharge stops, which reflects the recovery capability of the cable insulation material. If the starting voltage of the measured cable is low, it means that the insulation material is prone to partial discharge, and the loss degree of the target cable is large. If the termination voltage is high, it means that the recovery capability of the insulation material is good, and the loss degree of the target cable is small.

[0044] In an optional embodiment, the loss degree of the target cable is determined according to the starting voltage and the termination voltage, including: determining the number of times of partial discharge generated by the target cable in the current sampling period according to the starting voltage and the termination voltage; determining the loss degree of the target cable according to the starting voltage, the termination voltage, and the number of times of partial discharge.

[0045] Optionally, the number of times of partial discharge per cycle n pc is calculated according to the effective voltage value U0 of partial discharge, the starting voltage V I of partial discharge, and the termination voltage V X of partial discharge, so as to obtain the number of times of partial discharge per cycle. The calculation formula of the number of times of partial discharge per cycle n pc is as follows.

[0046]

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

[0048] Optionally, the degree of damage of the measured cable is analyzed according to the magnitude of the starting voltage V I of the partial discharge, the ending voltage V X of the partial discharge, and the number of partial discharges per cycle, wherein the starting voltage V I of the partial discharge is directly proportional to the degree of damage of the measured cable, i.e., the greater the starting voltage V I of the partial discharge, the greater the degree of damage of the measured cable, and the smaller the starting voltage V I of the partial discharge, the smaller the degree of damage of the measured cable; the ending voltage V X of the partial discharge is inversely proportional to the degree of damage of the measured cable, i.e., the higher the ending voltage V X of the partial discharge, the smaller the degree of damage of the measured cable, and the lower the ending voltage V X of the partial discharge, the greater the degree of damage of the measured cable; and the number of partial discharges is directly proportional to the degree of damage of the measured cable, i.e., the greater the number of partial discharges, the greater the degree of damage of the measured cable, and the smaller the number of partial discharges, the smaller the degree of damage of the measured cable.

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

[0050] Optionally, a plurality of starting voltage ranges and cable loss scores are pre-set, and a target starting voltage range to which the starting voltage of the measured cable belongs is determined from the plurality of starting voltage ranges when the starting voltage of the measured cable is determined; the cable loss score corresponding to the target starting voltage range is determined as the first loss score of the measured cable. A plurality of termination voltage ranges and cable loss scores are pre-set, and a target termination voltage range to which the termination voltage of the measured cable belongs is determined from the plurality of termination voltage ranges when the termination voltage of the measured cable is determined; the cable loss score corresponding to the target termination voltage range is determined as the second loss score of the measured cable. A plurality of partial discharge frequency ranges and cable loss scores are pre-set, and a target partial discharge frequency range to which the partial discharge frequency of the measured cable belongs is determined from the plurality of partial discharge frequency ranges when the partial discharge frequency of the measured cable is determined; the cable loss score corresponding to the target partial discharge frequency range is determined as the third loss score of the measured cable. A comprehensive loss score is obtained based on the first loss score, the second loss score, and the third loss score, and the loss degree of the measured cable is determined based on the comprehensive loss score; the comprehensive loss score can be directly used as the loss degree of the target cable; or a plurality of cable loss score ranges and cable loss levels are pre-set, and when the cable loss score range to which the comprehensive loss score belongs is known, the corresponding cable loss level is also determined, which can represent the loss degree of the target cable.

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

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

[0053] Optionally, according to the importance of the starting voltage, the ending voltage and the number of partial discharges to the degree of loss 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, the sum of the three weights is 100%, and the calculation formula of 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 the 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 the weights can be determined according to the actual situation and requirements, and the setting of the weights can be determined according to expert opinions, historical data, experience, etc. which is not limited here.

[0054] The plurality of voltage values corresponding to different sampling time points are obtained by the above-mentioned obtaining the plurality of voltage values of the target cable collected in the current sampling period. According to the plurality of voltage values, a plurality of voltage difference values are determined, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling time points. The plurality of voltage difference values are clustered to obtain feature voltage difference values corresponding to a plurality of clustering categories respectively. According to the feature voltage difference values corresponding to the plurality of clustering categories respectively, the starting voltage and the ending voltage of the local discharge of the target cable are obtained. According to the starting voltage and the ending voltage, the degree of loss of the target cable is determined. The technical problem that the cable partial discharge cannot be effectively and quickly detected is solved, the purpose of improving the detection efficiency and detection accuracy of the power cable partial discharge phenomenon is achieved, and the technical effect of reducing the safety risk existing in the operation of the power cable is achieved.

[0055] Based on the above-mentioned embodiments and optional embodiments, the present application proposes an optional implementation manner,

[0056] In step S1, a plurality of voltage values of a target cable collected in a current sampling period are obtained, wherein the plurality of voltage values correspond to different sampling time points, including: obtaining a plurality of partial discharge phase distribution spectrum maps collected in the current sampling period, wherein the plurality of partial discharge phase distribution spectrum maps correspond to different sampling time points; according to the plurality of partial discharge phase distribution spectrum maps, a plurality of discharge phases are obtained; according to the plurality of discharge phases, a plurality of voltage values are obtained, wherein the plurality of discharge phases and the plurality of voltage values correspond one by one.

[0057] Optionally, the voltage value generated by the partial discharge is usually low and susceptible to interference, and thus cannot be directly measured. In addition, the partial discharge usually occurs in a local area of a high-voltage device or insulating material, and it is difficult to directly measure the voltage value. In order to obtain the voltage value generated by the partial discharge, a high-frequency current sensor can be installed on the measured cable, and the sensor is 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 alternating voltage.

[0058] In step S2, a plurality of voltage difference values are determined according to the plurality of voltage values, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling time points.

[0059] Optionally, in this step, the voltage value corresponding to the first sampling point is subtracted from the voltage value corresponding to the second sampling point to obtain the 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 the 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. All voltage difference values are gathered together to obtain a data set of voltage difference values. The method for obtaining the data set of voltage difference values 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] In step S3, the plurality of voltage difference values are clustered to obtain a plurality of characteristic voltage difference values corresponding to a plurality of clustering categories, including: determining a plurality of initial clustering centers, wherein the plurality of initial clustering centers and the plurality of clustering categories correspond one by one; classifying the plurality of voltage difference values based on the distance from each initial clustering center in the plurality of initial clustering centers to obtain a plurality of clustering groups, wherein the plurality of clustering groups correspond one by one to the plurality of initial clustering centers; updating the plurality of initial clustering centers according to the voltage difference values included in the plurality of clustering groups to obtain a plurality of updated clustering centers; taking the plurality of updated clustering centers as new plurality of initial clustering centers, and repeating the above operation until a predetermined termination condition is reached; determining a plurality of characteristic voltage difference values corresponding to a plurality of clustering categories based on the plurality of clustering groups obtained when the predetermined termination condition is reached, wherein the plurality of clustering groups correspond one by one to the plurality of clustering categories.

[0061] Optionally, in the present application, the plurality of voltage difference values are divided into four groups according to size, and the uniform distribution sampling method is adopted to determine four initial clustering centers, the nearest voltage difference values are distributed to the corresponding new clustering groups, and the new clustering centers corresponding to the new clustering groups are calculated. Repeat this process until the clustering center and the group no longer change. Finally, four groups and four clustering centers are obtained, and the four groups are used as the categories of clustering, and the four clustering centers are used as the characteristic voltage difference values.

[0062] Step S4, according to the characteristic voltage difference values corresponding to the plurality of clustering categories respectively, the starting voltage and the termination voltage of the target cable generating partial discharge are obtained;

[0063] Optionally, four characteristic voltage difference values are obtained after clustering, the average value of the two characteristic voltage difference values with the largest absolute value in the four characteristic voltage difference values is calculated to obtain dV2, and the average value of the two characteristic voltage difference values with the smallest absolute value in the four characteristic voltage difference values is also calculated to obtain dV1. The starting voltage V I and the termination voltage V X of the partial discharge are calculated by dV2 and dV1, and the calculation formula is:

[0064]

[0065] Step S5, according to the starting voltage and the termination voltage, the damage degree of the target cable is determined, including: according to the starting voltage and the termination voltage, the number of times of partial discharge generated by the target cable in the current sampling period is determined; according to the starting voltage, the termination voltage and the number of times of partial discharge, the damage degree of the target cable is determined.

[0066] Optionally, according to the effective voltage value U0 of the partial discharge, the starting voltage V I , the termination voltage V X of the partial discharge, the number of times n pc of partial discharge per cycle is calculated, and the number of times of partial discharge per cycle is obtained. pc The calculation formula of the number of times n pc of partial discharge per cycle is as follows:

[0067]

[0068] Step S51, according to the starting voltage, the termination voltage and the number of times of partial discharge, the damage degree of the target cable is determined, including: based on the starting voltage, the first damage score of the target cable is determined; based on the termination voltage, the second damage score of the target cable is determined; based on the number of times of partial discharge, the third damage score of the target cable is determined; based on the first damage score, the second damage score and the third damage score, the comprehensive damage score of the target cable is obtained; based on the comprehensive damage score, the damage degree of the target cable is determined.

[0069] Optionally, a correspondence between a plurality of starting voltage ranges and cable loss scores can be pre-set, a target starting voltage range to which the starting voltage of the measured cable belongs can be determined from the plurality of starting voltage ranges when the starting voltage of the measured cable is determined, and a cable loss score corresponding to the target starting voltage range can be determined as the first loss score of the measured cable. The second loss score and the third loss score can be respectively determined by using a similar method, the comprehensive loss score can be obtained based on the first loss score, the second loss score and the third loss score, and the loss degree of the measured cable can be determined based on the comprehensive loss score. The comprehensive loss score can be directly used as the loss degree of the target cable, or a correspondence between a plurality of cable loss score ranges and cable loss levels can be pre-set, and when the cable loss score range to which the comprehensive loss score belongs is known, the corresponding cable loss level is also determined, which can represent the loss degree of the target cable. For example, the comprehensive loss score is 100 points in total, and the cable loss degree is divided into five levels, so that when the comprehensive loss score is 0-20 points, the cable loss degree is level one, when the comprehensive loss score is 21-40 points, the cable loss degree is level two, when the comprehensive loss score is 41-60 points, the cable loss degree is level three, when the comprehensive loss score is 61-80 points, the cable loss degree is level four, and when the comprehensive loss score is 81-100 points, the cable loss degree is level five.

[0070] In step S52, the comprehensive loss score of the target cable is obtained based on the first loss score, the second loss score and the third loss score, including: determining a first weight corresponding to the starting voltage, a second weight corresponding to the termination voltage, and a third weight corresponding to the number of partial discharges; and performing weighted calculation based on the first loss score, the second loss score, the third loss score, the first weight, the second weight and the third weight to obtain the comprehensive loss score.

[0071] Optionally, according to the importance of the starting voltage, the termination 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 termination voltage and the number of partial discharges are set respectively, the sum of the three weights is 100%, and the comprehensive loss score is obtained by multiplying and adding the three loss scores and the corresponding weights.

[0072] The above-mentioned optional implementation manner at least achieves the following effects: the technical problem that the cable partial discharge cannot be effectively and quickly detected is solved, the purpose of improving the detection efficiency and the detection accuracy of the power cable partial discharge phenomenon is achieved, and the technical effect of reducing the safety risk existing in the operation of the power cable is achieved.

[0073] It is noted that the steps illustrated in the flowchart of the figures can be performed in a computer system such as a set of computer-executable instructions executed by a computer system and that although the steps are illustrated, executed, or described in a sequential order, some or all of the steps order can be different from that which is illustrated herein or described herein.

[0074] A cable partial discharge detection device is also provided in the embodiments, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be described herein. As used below, the term "module" "device" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and contemplated.

[0075] According to the embodiments of the present application, a device embodiment for implementing the cable partial discharge detection method is also provided, Figure 3 A schematic diagram of a cable partial discharge detection device according to an embodiment of the present application is shown in Figure 3 The above-mentioned 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, a third determination module 35, and the device will be described below.

[0076] The first acquisition module 31 is configured to acquire a plurality of voltage values of a target cable collected in a current sampling period, wherein the plurality of voltage values correspond to different sampling time points;

[0077] The first determination module 32 is connected with the first acquisition module 31 and configured to determine a plurality of voltage difference values according to the plurality of voltage values, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling time points;

[0078] The first clustering module 33 is connected with the first determination module 32 and configured to cluster the plurality of voltage difference values to obtain a plurality of characteristic voltage difference values corresponding to a plurality of clustering categories respectively;

[0079] The second determination module 34 is connected with the first clustering module 33 and configured to obtain a starting voltage and a termination voltage of the partial discharge generated by the target cable according to the plurality of characteristic voltage difference values corresponding to the plurality of clustering categories respectively;

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

[0081] The cable partial discharge detection device provided by the embodiment of the present application comprises a first acquisition module, a first determination module, a first clustering module, a second determination module and a third determination module.

[0082] It should be noted that each of the above modules can be implemented by software or hardware. For example, for the latter, each of the above modules can be located in the same processor, or each of 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 above modules have the same instances and application scenarios as the corresponding steps, but are not limited to the content disclosed in the above embodiment. It should be noted that the above modules can run in a computer terminal as part of the device.

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

[0085] The cable partial discharge detection device can further comprise a processor and a memory, and 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 are stored in the memory as program units, and the processor executes the above program units stored in the memory to realize the corresponding functions.

[0086] The processor comprises a core, and the core retrieves the corresponding program unit from the memory. The core can be provided with one or more. The memory can include a non-persistent memory in a computer readable medium, a random access memory (RAM) and / or a non-volatile memory such as a read-only memory (ROM) or a flash memory (flash RAM), and the memory comprises at least one memory 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 method for detecting partial discharge of a cable 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 capable of running 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 can 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 focus. 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 exemplary. For example, the division of the above modules can be a logical function division. In actual implementation, there may be other division methods, 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 separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across 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, the functional modules in various embodiments of the present invention may be integrated into a single processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0094] If the above-mentioned integrated modules are realized in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable nonvolatile storage medium. Based on this understanding, the technical solutions of the present application, essentially or the part that contributes to the prior art, or all or part of the technical solutions 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 make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the embodiments of the present application. The aforementioned non-volatile storage medium includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0095] The above is only the preferred embodiment of the present application, and it should be pointed out that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method of detecting partial discharge in a cable, characterized by, The method comprises the following steps: obtaining a plurality of voltage values of the target cable collected in a current sampling period, wherein the plurality of voltage values correspond to different sampling time points; determining a plurality of voltage difference values according to the plurality of voltage values, wherein the voltage difference value is the difference between the voltage values collected at two adjacent sampling time points; clustering the plurality of voltage difference values to obtain feature voltage difference values corresponding to a plurality of clustering categories respectively; obtaining a starting voltage and a termination voltage of the local discharge of the target cable according to the feature voltage difference values corresponding to the plurality of clustering categories respectively; determining the degree of loss of the target cable according to the starting voltage and the termination voltage; wherein the step of obtaining a plurality of voltage values of the target cable collected in a current sampling period, wherein the plurality of voltage values correspond to different sampling time points, comprises: obtaining a plurality of local discharge phase distribution spectrum maps collected in the current sampling period, wherein the plurality of local discharge phase distribution spectrum maps correspond to different sampling time points; obtaining a plurality of discharge phases according to the plurality of local discharge phase distribution spectrum maps; and obtaining the plurality of voltage values according to the plurality of discharge phases, wherein the plurality of discharge phases and the plurality of voltage values correspond to each other one by one; wherein the step of obtaining a starting voltage and a termination voltage of the local discharge of the target cable according to the feature voltage difference values corresponding to the plurality of clustering categories respectively, comprises: calculating the average value of the two smallest absolute value feature voltage difference values to obtain a first average value, calculating the average value of the two largest absolute value feature voltage difference values to obtain a second average value, and calculating the starting voltage and the termination voltage through the first average value and the second average value, the calculation formula being as follows: ; wherein, is the first average value, is the second average value, is the starting voltage, is the end voltage.

2. The method of claim 1, wherein, the step of clustering the plurality of voltage difference values to obtain feature voltage difference values corresponding to a plurality of clustering categories respectively, comprises: determining a plurality of initial clustering centers, wherein the plurality of initial clustering centers and the plurality of clustering categories correspond to each other one by one; classifying the plurality of voltage difference values based on the distance from each initial clustering center in the plurality of initial clustering centers to the plurality of voltage difference values to obtain a plurality of clustering groups, wherein the plurality of clustering groups and the plurality of initial clustering centers correspond to each other one by one; updating the plurality of initial clustering centers according to the voltage difference values included in the plurality of clustering groups to obtain a plurality of updated clustering centers; taking the plurality of updated clustering centers as new plurality of initial clustering centers, and repeating the above operations until a predetermined termination condition is reached; determining the feature voltage difference values corresponding to the plurality of clustering categories based on the plurality of clustering groups obtained when the predetermined termination condition is reached, wherein the plurality of clustering groups and the plurality of clustering categories correspond to each other one by one.

3. The method of claim 1, wherein, the step of determining the degree of loss of the target cable according to the starting voltage and the termination voltage, comprises: determining the number of times of local discharge of the target cable in the current sampling period according to the starting voltage and the termination voltage; determining the degree of loss of the target cable according to the starting voltage, the termination voltage, and the number of times of local discharge.

4. The method of claim 3, wherein the starting voltage is directly proportional to the degree of loss of the target cable; the ending voltage is inversely proportional to the degree of loss of the target cable; and the number of partial discharges is directly proportional to the degree of loss of the target cable. The determining of the degree of loss 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 of the target cable based on the ending voltage; 5. The method of claim 3, wherein, 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 degree of loss of the target cable based on the comprehensive loss score. The obtaining of the comprehensive loss score of the target cable based on the first loss score, the second loss score and the third loss score comprises: 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; and performing weighted calculation based on the first loss score, the second loss score, the third loss score, the first weight, the second weight and the third weight to obtain the comprehensive loss score.

6. The method of claim 5, wherein, The method comprises: a first acquisition module configured to acquire a plurality of voltage values of a target cable collected in a current sampling period, wherein the plurality of voltage values correspond to different sampling time points; a first determination module configured to determine a plurality of voltage difference values based on the plurality of voltage values, wherein the voltage difference values are differences between voltage values collected at two adjacent sampling time points; 7. A partial discharge detection apparatus for a cable, characterized by a first clustering module configured to cluster the plurality of voltage difference values to obtain characteristic voltage difference values corresponding to a plurality of clustering categories respectively; a second determination module configured to obtain starting voltage and ending voltage of partial discharge of the target cable based on the characteristic voltage difference values corresponding to the plurality of clustering categories respectively; a third determination module configured to determine a degree of loss of the target cable based on the starting voltage and the ending voltage. The first acquisition module is further configured to acquire a plurality of partial discharge phase distribution spectrograms collected in the current sampling period, wherein the plurality of partial discharge phase distribution spectrograms correspond to different sampling time points; to obtain a plurality of discharge phases based on the plurality of partial discharge phase distribution spectrograms; and to obtain the plurality of voltage values based on the plurality of discharge phases, wherein the plurality of discharge phases and the plurality of voltage values correspond to each other one by one. The second determination module is further configured to calculate an average value of two smallest absolute values of the characteristic voltage difference values to obtain a first average value, to calculate an average value of two largest absolute values of the characteristic voltage difference values to obtain a second average value, and to calculate the starting voltage and the ending voltage based on the first average value and the second average value, according to the following formula: ​ ​ ​ ; wherein, is the first average value, is the second average value, is the starting voltage, is the ending voltage.

8. A non-volatile storage medium, comprising: The non-volatile storage medium stores a plurality of instructions adapted to be loaded by a processor and to execute the cable partial discharge detection method according to any one of claims 1 to 6.

9. An electronic device, comprising: Comprise: One or more processors and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the cable partial discharge detection method according to any one of claims 1 to 6.

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