Partial discharge detection system and method for a self-powered cable

Abstract

This application relates to the field of partial discharge detection in cables, specifically to a partial discharge detection system and method for self-powered cables. It allows for a more comprehensive determination of whether a cable under test has experienced partial discharge, improving the reliability and objectivity of the partial discharge detection results, given the availability of multiple judgment criteria. The partial discharge detection system for self-powered cables includes: a preset signal extraction module that extracts preset signals, including at least one of a preset electrical signal, a preset ultrasonic signal, and a preset optical signal; a detection module that detects at least one of the actual electrical signal, actual ultrasonic signal, and actual optical signal of the cable under test within a preset time period; and a judgment module that determines whether the cable under test has experienced partial discharge based on at least one of the differences between the actual electrical signal and the preset electrical signal, the differences between the actual ultrasonic signal and the preset ultrasonic signal, and the differences between the preset optical signal and the actual optical signal.

Description

Technical Field

[0001] This application relates to the field of partial discharge detection in cables, and specifically to a partial discharge detection system and method for self-powered cables. Background Technology

[0002] With the acceleration of urbanization and the continuous growth of electricity demand, the cables under test, as the main carriers of urban power supply, are crucial to the normal operation of cities due to their safety and stability. During operation, these cables may encounter various faults, which can lead to power outages and even safety accidents such as fires. Therefore, real-time fault monitoring of these cables is of significant practical importance. Detecting characteristic quantities such as partial discharge and harmonic current in the cable is crucial monitoring information for identifying whether a fault has occurred.

[0003] However, traditional cable partial discharge detection technology cannot accurately obtain the detection results of partial discharge in the cable under test. It suffers from low detection accuracy and lacks comprehensiveness and objectivity in the detection results, which leads to the risk of partial discharge in the cable under test. Summary of the Invention

[0004] The purpose of this application is to provide a partial discharge detection system and method for self-powered cables, which can accurately determine whether partial discharge has occurred in the cable under test, thereby improving the reliability and comprehensiveness of the partial discharge detection results. To achieve the purpose of this application, the following technical solution is provided:

[0005] In a first aspect, this application provides a partial discharge detection system for self-powered cables, comprising:

[0006] A preset signal extraction module is used to extract a preset signal, wherein the preset signal includes at least one of a preset electrical signal, a preset ultrasonic signal, and a preset optical signal;

[0007] The detection module is used to detect at least one of the actual electrical signal, actual ultrasonic signal, and actual optical signal of the cable under test within a preset time.

[0008] The judgment module is used to determine whether the cable under test has partial discharge based on at least one of the differences between the actual electrical signal and the preset electrical signal, the differences between the actual ultrasonic signal and the preset ultrasonic signal, and the differences between the preset optical signal and the actual optical signal. The input terminal of the judgment module is electrically connected to the output terminal of the preset signal extraction module and the output terminal of the detection module.

[0009] In one embodiment, the partial discharge detection system for self-powered cables further includes:

[0010] Also includes:

[0011] A first control module is configured to send a first test command and control the detection module to detect the actual electrical signal of the cable under test according to the first test command. The test command includes at least one of a pulse signal test command, a current test command, and a voltage test command. The output terminal of the first control module is electrically connected to the input terminal of the detection module.

[0012] The second control module is used to send a second test command and control the detection module to detect the actual ultrasonic signal of the cable under test according to the second test command. The output terminal of the second control module is electrically connected to the input terminal of the detection module.

[0013] The third control module is used to send a third test command and control the detection module to detect the actual optical signal of the cable under test according to the third test command. The output terminal of the third control module is electrically connected to the input terminal of the detection module.

[0014] In one embodiment, the determination module includes:

[0015] The first electrical signal judgment module is used to obtain the pulse matching value of the pulse electrical signal of the cable under test within a preset time when the first control module sends a pulse signal test command, and to determine whether the cable under test is partially discharged based on the difference between the pulse matching value and the preset pulse matching value. The input terminal of the first electrical signal judgment module is electrically connected to the output terminal of the detection module.

[0016] The second electrical signal judgment module is used to obtain the current value of the cable under test when the first control module sends a current signal test command, and to determine whether the cable under test is partially discharged based on the difference between the current value and the preset current value. The input terminal of the second electrical signal judgment module is electrically connected to the output terminal of the detection module.

[0017] The third electrical signal judgment module is used to acquire the voltage value of the cable under test when the first control module sends a voltage signal test command, and to determine whether the cable under test is partially discharged based on the difference between the voltage value and the preset voltage value. The input terminal of the third electrical signal judgment module is electrically connected to the output terminal of the detection module.

[0018] In one embodiment, the partial discharge detection system for self-powered cables further includes:

[0019] The pulse signal acquisition module is used to acquire the frequency information, amplitude information and waveform length information of the pulse electrical signal of the cable under test within a preset time.

[0020] The calculation module is used to calculate the pulse matching value of the pulse electrical signal of the cable under test within a preset time according to the frequency information, the amplitude information and the waveform length information. The input terminal of the first judgment module is electrically connected to the output terminal of the pulse signal acquisition module, and the output terminal of the calculation module is electrically connected to the input terminal of the first electrical signal judgment module.

[0021] In one embodiment, the pulse signal acquisition module includes a discharge induction coil.

[0022] In one embodiment, the determination module further includes:

[0023] An ultrasonic signal detection module is used to acquire the ultrasonic frequency and ultrasonic amplitude of the cable under test when the second control module sends an ultrasonic signal test command, and to determine whether the cable under test has partial discharge based on the difference between the ultrasonic frequency and the preset ultrasonic frequency amplitude. The input terminal of the ultrasonic signal detection module is electrically connected to the output terminal of the detection module.

[0024] In one embodiment, the ultrasonic signal detection module includes an ultrasonic sensor.

[0025] In one embodiment, the determination module further includes:

[0026] The optical signal detection module is used to obtain the number of photons in the cable under test when the third control module sends an optical signal test command, and to determine whether the cable under test is partially discharged based on the difference between the number of photons and the preset number of photons. The input end of the optical signal detection module is electrically connected to the output end of the detection module.

[0027] In one embodiment, the optical signal detection module includes an ultraviolet light sensor.

[0028] Secondly, this application provides a method for detecting partial discharge in self-powered cables, comprising:

[0029] Extract preset signals, which include preset electrical signals, preset ultrasonic signals, and preset optical signals;

[0030] The actual electrical signal, actual ultrasonic signal, and actual optical signal of the cable under test are detected within a preset time.

[0031] The presence of partial discharge in the cable under test is determined based on the difference between the actual electrical signal and the preset electrical signal, the difference between the actual ultrasonic signal and the preset ultrasonic signal, and the difference between the preset optical signal and the actual optical signal.

[0032] The partial discharge detection system and method for self-powered cables disclosed in this application extracts preset signals through a preset signal extraction module. These preset signals include at least one of preset electrical signals, preset ultrasonic signals, and preset optical signals, providing the basis for determining whether partial discharge has occurred in the cable under test. The detection module then detects at least one of the actual electrical signals, actual ultrasonic signals, and actual optical signals of the cable under test within a preset time period, obtaining discharge information from multiple detection dimensions within that time period, resulting in more comprehensive detection results. Finally, the judgment module determines whether the cable under test is partially discharged based on at least one of the differences between the actual electrical signals and preset electrical signals, the differences between the actual ultrasonic signals and preset ultrasonic signals, and the differences between the preset optical signals and actual optical signals. This allows for a more comprehensive determination of whether partial discharge has occurred in the cable under test, improving the reliability and objectivity of the partial discharge detection results, even with multiple judgment criteria. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments or conventional technologies of this disclosure, the accompanying drawings used in the description of the embodiments or conventional technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic structural diagram of a partial discharge detection system for a self-powered cable provided in an embodiment of this application;

[0035] Figure 2 This is a schematic structural diagram of another partial discharge detection system for self-powered cables provided in the embodiments of this application;

[0036] Figure 3 This is a schematic flowchart of a partial discharge detection method for self-powered cables provided in an embodiment of this application.

[0037] Explanation of reference numerals in the attached figures

[0038] 10. Preset signal extraction module; 20. Detection module; 30. Judgment module; 301. First electrical signal judgment module; 302. Second electrical signal judgment module; 303. Third electrical signal judgment module; 304. Pulse signal acquisition module; 305. Calculation module; 306. Ultrasonic signal detection module; 307. Optical signal detection module; 40. First control module; 50. Second control module; 60. Third control module. Detailed Implementation

[0039] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0041] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “comprise” and / or “comprising” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0042] With the acceleration of urbanization and the continuous growth of electricity demand, the cables under test, as the main carriers of urban power supply, are crucial to the normal operation of cities due to their safety and stability. During operation, these cables may encounter various faults, which can lead to power outages and even safety accidents such as fires. Therefore, real-time fault monitoring of these cables is of significant practical importance. Detecting characteristic quantities such as partial discharge and harmonic current in the cable is crucial monitoring information for identifying whether a fault has occurred.

[0043] However, traditional cable partial discharge detection technology cannot accurately obtain the detection results of partial discharge in the cable under test. It suffers from low detection accuracy and lacks comprehensiveness and objectivity in the detection results, which leads to the risk of partial discharge in the cable under test.

[0044] This application provides a partial discharge detection system for self-powered cables. Please refer to [link to relevant documentation]. Figure 1The partial discharge detection system for self-powered cables includes a preset signal extraction module 10, a detection module 20, and a judgment module 30. The preset signal extraction module 10 extracts preset signals, which include at least one of a preset electrical signal, a preset ultrasonic signal, and a preset optical signal. The detection module 20 detects at least one of the actual electrical signal, actual ultrasonic signal, and actual optical signal of the cable under test within a preset time. The judgment module 30 determines whether the cable under test is partially discharged based on at least one of the differences between the actual electrical signal and the preset electrical signal, the differences between the actual ultrasonic signal and the preset ultrasonic signal, and the differences between the preset optical signal and the actual optical signal. The input terminal of the judgment module 30 is electrically connected to the output terminal of the preset signal extraction module 10 and the output terminal of the detection module 20.

[0045] For example, the preset electrical signal, preset ultrasonic signal, and preset optical signal can all be set according to actual conditions. Specifically, the preset electrical signal may include a preset pulse signal, a preset current signal, and a preset voltage signal. The preset electrical signal, preset ultrasonic signal, and preset optical signal are all electrical, ultrasonic, and optical signals of the cable under test when partial discharge occurs. Based on at least one of the differences between the actual electrical signal and the preset electrical signal, the differences between the actual ultrasonic signal and the preset ultrasonic signal, and the differences between the preset optical signal and the actual optical signal, it can be accurately determined whether the cable under test is partially discharged, thereby improving the reliability of the cable.

[0046] The partial discharge detection system for self-powered cables disclosed in this application extracts preset signals through a preset signal extraction module 10. These preset signals include at least one of preset electrical signals, preset ultrasonic signals, and preset optical signals, providing the basis for determining whether partial discharge has occurred in the cable under test. The detection module 20 then detects at least one of the actual electrical signals, actual ultrasonic signals, and actual optical signals of the cable under test within a preset time period, obtaining discharge information from multiple detection dimensions within that time period, resulting in more comprehensive detection results. Finally, the judgment module 30 determines whether the cable under test is partially discharged based on at least one of the differences between the actual electrical signals and preset electrical signals, the differences between the actual ultrasonic signals and preset ultrasonic signals, and the differences between the preset optical signals and actual optical signals. This allows for a more comprehensive determination of whether partial discharge has occurred in the cable under test, improving the reliability and objectivity of the partial discharge detection results, even with multiple judgment criteria.

[0047] In some embodiments, please continue reading Figure 2The system also includes: a first control module 40, used to send a first test command and control the detection module 20 to detect the actual electrical signal of the cable under test according to the first test command, wherein the test command includes at least one of a pulse signal test command, a current test command, and a voltage test command, and the output terminal of the first control module 40 is electrically connected to the input terminal of the detection module 20; a second control module 50, used to send a second test command and control the detection module 20 to detect the actual ultrasonic signal of the cable under test according to the second test command, and the output terminal of the third control module 60 is electrically connected to the input terminal of the detection module 20; and a third control module, used to send a third test command and control the detection module 20 to detect the actual optical signal of the cable under test according to the third test command, and the output terminal of the third control module is electrically connected to the input terminal of the detection module 20.

[0048] As an example, the first control module 40, the second control module 50, and the third control module 60 can send first test commands, second test commands, and third test commands according to test requirements to control the detection module 20 to detect the actual electrical signals, actual ultrasonic signals, and actual optical signals of the cable under test. Specifically, the first control module 40, the second control module 50, and the third control module 60 can select to send the first test commands, the second test commands, and the third test commands according to the environment in which the cable is located and the actual conductivity of the cable.

[0049] The partial discharge detection system for self-powered cables in this application embodiment, through the first control module 40, the second control module 50 and the third control module 60, can send first test instructions, second test instructions and third test instructions according to test requirements to control the detection module 20 to detect the actual electrical signals, actual ultrasonic signals and actual optical signals of the cable under test, so as to realize multi-faceted detection of the cable and improve the accuracy and comprehensiveness of the detection results.

[0050] In some embodiments, please continue reading Figure 2The judgment module 30 includes: a first electrical signal judgment module 301, used to acquire the pulse matching value of the pulse electrical signal of the cable under test within a preset time when the first control module 40 sends a pulse signal test command, and to determine whether the cable under test is partially discharged based on the difference between the pulse matching value and the preset pulse matching value; the input terminal of the first electrical signal judgment module 301 is electrically connected to the output terminal of the detection module 20; a second electrical signal judgment module 302, used to acquire the current value of the cable under test when the first control module 40 sends a current signal test command, and to determine whether the cable under test is partially discharged based on the difference between the current value and the preset current value; the input terminal of the second electrical signal judgment module 302 is electrically connected to the output terminal of the detection module 20; and a third electrical signal judgment module 303, used to acquire the voltage value of the cable under test when the first control module 40 sends a voltage signal test command, and to determine whether the cable under test is partially discharged based on the difference between the voltage value and the preset voltage value; the input terminal of the third electrical signal judgment module 303 is electrically connected to the output terminal of the detection module 20.

[0051] As an example, the first electrical signal judgment module 301 is used to obtain the pulse matching value of the pulse electrical signal of the cable under test within a preset time when the first control module 40 sends a pulse signal test command. Specifically, the pulse electrical signal of the cable under test within a preset time can be obtained by installing an induction coil in the circumferential direction of the cable under test.

[0052] In another example, a discharge current sensor can be installed on the cable under test to collect the current value of the cable under test. This current value is a pulse current signal released due to partial discharge in the cable under test. Further, the second electrical signal judgment module 302 determines whether the cable under test is partially discharged by comparing the current value with a preset current value. More specifically, after collecting the current value of the cable under test, the current value can be filtered to obtain a current signal that is easier to determine whether partial discharge has occurred.

[0053] In yet another example, a voltage sensor can be mounted on the cable under test to collect the voltage value of the cable under test. More specifically, if the voltage value is not 0, the cable under test is experiencing partial discharge.

[0054] The partial discharge detection system for self-powered cables in this application embodiment, by setting induction coils, current sensors, and voltage sensors, can more comprehensively detect whether partial discharge has occurred in the cable under test, thereby avoiding the problem of low reliability of detection results caused by incomplete detection.

[0055] In some embodiments, please continue reading Figure 2The partial discharge detection system for self-powered cables further includes: a pulse signal acquisition module 304, used to acquire the frequency information, amplitude information, and waveform length information of the pulse electrical signal of the cable under test within a preset time; a calculation module 305, used to calculate the pulse matching value of the pulse electrical signal of the cable under test within a preset time based on the frequency information, amplitude information, and waveform length information; the input terminal of the first judgment module 30 is electrically connected to the output terminal of the pulse signal acquisition module 304; and the output terminal of the calculation module 305 is electrically connected to the input terminal of the first electrical signal judgment module 301.

[0056] As an example, the calculation module 305 can compare the pulse frequency range with a preset pulse frequency range. The preset pulse frequency is the pulse frequency range of the cable when no partial discharge occurs. This allows the calculation of the number of times the actual pulse frequency of the cable under test coincides with the preset pulse frequency within a preset time, as well as the number of integer pulse frequencies of partial discharge, thus obtaining the frequency matching degree. Furthermore, the intensity coefficient is calculated using the pulse amplitude and the pulse amplitude threshold of the partial discharge signal. The specific calculation formula is as follows:

[0057] +

[0058] In the formula, Q is the intensity coefficient; a is the number of pulse signals; v(i) is the amplitude of the i-th pulse signal; v(0) is the amplitude threshold of the partial discharge signal; v(j) is the amplitude of the j-th pulse signal; and v(j-1) is the amplitude of the (j-1)-th pulse signal. Further, based on the waveform curves and by sequentially importing the waveform curves of the received pulse signals within a preset time period into the same coordinate system of the CAD software, the length of the waveform curve of the received pulse signals within the preset time period is obtained, and the average waveform curve length is calculated. Then, after importing all the waveform curves of the received pulse signals within the preset time period into the same coordinate system of the CAD software, a superposition analysis is performed to obtain the overall waveform overlap curve length. The ratio of the overall waveform overlap curve length to the average waveform curve length is calculated to obtain the waveform regularity. Based on the frequency regularity, intensity coefficient, and waveform regularity, the pulse matching value is calculated. Specifically, the pulse matching value can be calculated using the following formula:

[0059]

[0060] In the formula, Z is the pulse matching value; m is the sum of frequency matching degree, intensity coefficient, and waveform regularity matching degree. The overall matching degree is compared with a preset reasonable threshold for pulse signal overall matching degree to determine whether the cable under test has partial discharge.

[0061] The partial discharge detection system for self-powered cables in this application calculates the pulse matching value by using frequency matching degree, intensity coefficient, and waveform regularity matching degree. This allows for a more accurate acquisition of the actual pulse signal of the cable under test, correcting inaccurate and incomplete detection results, and improving the accuracy of pulse signal detection for the cable under test.

[0062] In some embodiments, please continue reading Figure 2 The pulse signal acquisition module 304 includes a discharge induction coil.

[0063] As an example, a discharge induction coil can work on the principle of electromagnetic induction. When current flows through the cable under test, an electromagnetic field is generated around the cable, thereby inducing a pulse electrical signal.

[0064] The partial discharge detection system for self-powered cables in this application embodiment acquires the pulse signal of the cable under test through an induction coil, which can detect the pulse signal of the cable under test over a wider range, and can reduce ionization and chemical interference, and improve the accuracy and precision of the detection results.

[0065] In some embodiments, please continue reading Figure 2 The judgment module 30 further includes an ultrasonic signal detection module 306, which is used to acquire the ultrasonic frequency and ultrasonic amplitude of the cable under test when the second control module 50 sends an ultrasonic signal test command, and to determine whether the cable under test has partial discharge based on the difference between the ultrasonic frequency and the preset ultrasonic frequency amplitude. The input end of the ultrasonic signal detection module 306 is electrically connected to the output end of the detection module 20.

[0066] As an example, after the ultrasonic signal detection module 306 acquires the ultrasonic frequency and ultrasonic amplitude of the cable under test, before determining whether the cable under test has partial discharge based on the difference between the ultrasonic frequency and the preset ultrasonic frequency amplitude, signal filtering and amplification preprocessing can be performed on the ultrasonic frequency and ultrasonic amplitude.

[0067] In some embodiments, please continue reading Figure 2 The ultrasonic signal detection module 306 includes an ultrasonic sensor.

[0068] As an example, an ultrasonic sensor can convert electrical energy into mechanical oscillations to generate ultrasonic waves. When the ultrasonic waves encounter the object or medium being measured, they will be reflected or refracted, and then the echo will be received by a receiver. The receiver will then convert the mechanical vibration of the echo into an electrical signal, thereby detecting the ultrasonic signal.

[0069] The partial discharge detection system for self-powered cables in this application embodiment uses an ultrasonic sensor with advantages such as high frequency, high sensitivity, and strong penetration, which can detect external or deep objects. Therefore, it can obtain more accurate ultrasonic detection signals and improve the accuracy and objectivity of the detection results.

[0070] In some embodiments, please continue reading Figure 2 The judgment module 30 further includes: an optical signal detection module 307, which is used to obtain the number of photons in the cable under test when the third control module 60 sends an optical signal test command, and to determine whether the cable under test is partially discharged based on the difference between the number of photons and the preset number of photons. The input end of the optical signal detection module 307 is electrically connected to the output end of the detection module 20.

[0071] As an example, the optical signal detection module 307 acquires the number of photons in the cable under test and determines whether the cable under test has partial discharge based on the difference between the number of photons and a preset number of photons. Partial discharge in the cable under test can be determined through optical detection.

[0072] In some embodiments, please continue reading Figure 2 The optical signal detection module 307 includes an ultraviolet light sensor.

[0073] As an example, an ultraviolet light sensor can convert ultraviolet signals into electrical signals using a photosensitive element, thereby acquiring the optical signal of the cable under test.

[0074] The partial discharge detection system for self-powered cables in this application embodiment uses an ultraviolet light sensor that has advantages such as high sensitivity, high output, and high response speed. Furthermore, the ultraviolet light sensor has strong anti-interference ability and good stability, and can more comprehensively measure the optical signal of the cable under test. It can also convert the detected optical signal into an electrical signal, which can more intuitively determine whether the cable under test has experienced partial discharge, thereby improving the reliability and objectivity of the detection results.

[0075] It should be noted that the partial discharge detection system for self-powered cables in this embodiment may further include: a first temperature sensor, installed on the cable under test, for collecting the actual temperature of the cable joint; and a second temperature sensor, installed near the cable under test, for collecting the ambient temperature around the cable. If the difference between the actual temperature and the ambient temperature exceeds a first preset value, an alarm signal is issued if the cable under test is found to be abnormal. By detecting the actual temperature at different locations of the cable joint and the surrounding ambient temperature, the abnormality of the cable's operating status can be determined. Compared to relying solely on cable temperature to determine the abnormality, this method significantly improves the accuracy of temperature monitoring. More specifically, the alarm signal may include an audible alarm, a visual alarm, or an audible and visual alarm.

[0076] It should be noted that the partial discharge detection system for self-powered cables in this embodiment may further include: a grounding current sensor, installed on the cable under test, for collecting the grounding current of the metal sheath of the cable under test. When the grounding current exceeds a second preset value, an abnormality is detected in the cable under test, and an alarm signal is issued. Specifically, the grounding current sensor may be a Rogowski coil. This embodiment, by monitoring the grounding current in real time, will immediately issue an alarm signal if a fault occurs in the cable under test, causing the grounding current to increase and exceed the second preset value, thereby improving the safety and reliability of the working cable.

[0077] It should be noted that the partial discharge detection system for self-powered cables in this application embodiment may further include: a vibration sensor, installed on the cable under test, for collecting vibration signals from the cable under test. The signal characteristics of the vibration signal are compared with those under different operating conditions to determine whether external force damage exists. The signal characteristics include time-domain and frequency-domain characteristics. Specifically, the database stores the time-domain and frequency-domain characteristics of the vibration signals of the cable under test under different operating conditions, such as: the signal characteristics and thresholds of the cable in a normal quiet state, the signal characteristics and thresholds when a person cuts the cable with tools, the signal characteristics and thresholds when an excavator touches the cable while working nearby, and the signal characteristics and thresholds when the cable is struck by lightning. When a vibration signal is received, its signal characteristics are first compared with the signal characteristics and thresholds under normal quiet conditions in the database. If it exceeds the threshold range, it indicates an abnormal vibration signal, thus confirming the presence of external force damage. Further comparison with the signal characteristics and thresholds of various abnormal situations in the database determines the cause of the external force damage, thus determining whether someone is cutting the cable, whether an excavator has dug up the cable, etc.

[0078] It should be noted that after the partial discharge detection system for self-powered cables in the application embodiment issues an alarm signal, the system can also accurately locate the abnormal position of the cable under test. Specifically, this includes emitting a laser from the light source module, laying a sensing fiber along the cable under test, and when the light signal propagates in the sensing fiber, it interacts with the medium in the sensing fiber to generate backscattered light. Optical time-domain reflectometry (OTDR) technology is used to detect the backscattered light generated in the sensing fiber. The backscattered light contains physical quantity information along the cable, and the collected backscattered light signal is converted... The signal is an electrical signal used to acquire signals containing physical quantities along the cable under test, including temperature, strain, and vibration. The judgment module 30 identifies abnormal events occurring along the cable based on a pattern recognition algorithm. It uses the support vector machine in the pattern recognition algorithm to extract key features, such as the temperature, strain, and vibration physical quantity information along the cable, thereby accurately identifying the abnormal state of the cable, timely detecting and handling cable damage events, and improving the safety and stability of the power system. At the same time, through time difference positioning, the location of the abnormal event is calculated by using the time and speed of light pulse propagation in optical fiber in optical time domain reflectometer technology, thereby completing the fault location.

[0079] This application also provides a partial discharge detection method for self-powered cables, as shown in the figure, including:

[0080] S11: Extract preset signals, which include preset electrical signals, preset ultrasonic signals, and preset optical signals.

[0081] S12: Detect the actual electrical signal, actual ultrasonic signal and actual optical signal of the cable under test within a preset time.

[0082] S13: Determine whether the cable under test is partially discharged based on the difference between the actual electrical signal and the preset electrical signal, the difference between the actual ultrasonic signal and the preset ultrasonic signal, and the difference between the preset optical signal and the actual optical signal.

[0083] The partial discharge detection method for self-powered cables disclosed in this application extracts preset signals, including at least one of preset electrical signals, preset ultrasonic signals, and preset optical signals, to obtain the judgment criteria for determining whether partial discharge has occurred in the cable under test by the partial discharge detection system for self-powered cables. Then, by detecting at least one of the actual electrical signals, actual ultrasonic signals, and actual optical signals of the cable under test within a preset time period, discharge information from multiple detection dimensions of the cable under test within the preset time period can be obtained, resulting in more comprehensive detection results. Finally, based on at least one of the differences between the actual electrical signals and preset electrical signals, the differences between the actual ultrasonic signals and preset ultrasonic signals, and the differences between preset optical signals and actual optical signals, the method determines whether the cable under test is partially discharged. Therefore, by obtaining multiple judgment criteria, a more comprehensive judgment on whether partial discharge has occurred in the cable under test can be made, improving the reliability and objectivity of the cable partial discharge detection results.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A partial discharge detection system for self-powered cables, characterized in that, include: A preset signal extraction module is used to extract a preset signal, wherein the preset signal includes at least one of a preset electrical signal, a preset ultrasonic signal, and a preset optical signal; The detection module is used to detect at least one of the actual electrical signal, actual ultrasonic signal, and actual optical signal of the cable under test within a preset time. A first temperature sensor is installed on the cable under test to collect the actual temperature of the cable joint of the cable under test. A second temperature sensor is installed near the cable under test to collect the ambient temperature around the cable under test. If the difference between the actual temperature and the ambient temperature is greater than a first preset value, then the cable under test is abnormal and an alarm signal is issued. A grounding current sensor is installed on the cable under test to collect the grounding current of the metal sheath of the cable under test; when the grounding current is greater than a second preset value, the cable under test is found to be abnormal and an alarm signal is issued. The light source emitting module is used to emit laser after the alarm signal is issued. When the detection light signal propagates in the sensing optical fiber laid along the cable under test, it interacts with the medium in the sensing optical fiber to generate backscattered light. The collected backscattered light signal is converted into an electrical signal to obtain a signal containing physical quantities along the cable under test, including temperature, strain and vibration. The judgment module is used to determine whether the cable under test is partially discharged based on at least one of the differences between the actual electrical signal and the preset electrical signal, the differences between the actual ultrasonic signal and the preset ultrasonic signal, and the differences between the preset optical signal and the actual optical signal. The input terminal of the judgment module is electrically connected to the output terminal of the preset signal extraction module and the output terminal of the detection module. Based on the pattern recognition algorithm, abnormal events occurring along the cable under test are identified. The support vector machine in the pattern recognition algorithm is used to extract the temperature, strain, and vibration physical quantity information along the cable under test to identify the abnormal state of the cable under test. The abnormal event is located by time difference positioning and the location of the abnormal event is calculated by the time and speed of light pulse propagation in the optical fiber in the optical time domain reflectometer technology.

2. The partial discharge detection system for self-powered cables according to claim 1, characterized in that, Also includes: A first control module is configured to send a first test command and control the detection module to detect the actual electrical signal of the cable under test according to the first test command. The test command includes at least one of a pulse signal test command, a current test command, and a voltage test command. The output terminal of the first control module is electrically connected to the input terminal of the detection module. The second control module is used to send a second test command and control the detection module to detect the actual ultrasonic signal of the cable under test according to the second test command. The output terminal of the second control module is electrically connected to the input terminal of the detection module. The third control module is used to send a third test command and control the detection module to detect the actual optical signal of the cable under test according to the third test command. The output terminal of the third control module is electrically connected to the input terminal of the detection module.

3. The partial discharge detection system for self-powered cables according to claim 2, characterized in that, The judgment module includes: The first electrical signal judgment module is used to obtain the pulse matching value of the pulse electrical signal of the cable under test within a preset time when the first control module sends a pulse signal test command, and to determine whether the cable under test is partially discharged based on the difference between the pulse matching value and the preset pulse matching value. The input terminal of the first electrical signal judgment module is electrically connected to the output terminal of the detection module. The second electrical signal judgment module is used to obtain the current value of the cable under test when the first control module sends a current signal test command, and to determine whether the cable under test is partially discharged based on the difference between the current value and the preset current value. The input terminal of the second electrical signal judgment module is electrically connected to the output terminal of the detection module. The third electrical signal judgment module is used to acquire the voltage value of the cable under test when the first control module sends a voltage signal test command, and to determine whether the cable under test is partially discharged based on the difference between the voltage value and the preset voltage value. The input terminal of the third electrical signal judgment module is electrically connected to the output terminal of the detection module.

4. The partial discharge detection system for self-powered cables according to claim 3, characterized in that, The judgment module also includes: The pulse signal acquisition module is used to acquire the frequency information, amplitude information and waveform length information of the pulse electrical signal of the cable under test within a preset time. The calculation module is used to calculate the pulse matching value of the pulse electrical signal of the cable under test within a preset time according to the frequency information, the amplitude information and the waveform length information. The output terminal of the calculation module is electrically connected to the input terminal of the first electrical signal judgment module, and the input terminal of the calculation module is electrically connected to the output terminal of the pulse signal acquisition module.

5. The partial discharge detection system for self-powered cables according to claim 4, characterized in that, The pulse signal acquisition module includes a discharge induction coil.

6. The partial discharge detection system for self-powered cables according to claim 2, characterized in that, The judgment module also includes: An ultrasonic signal detection module is used to acquire the ultrasonic frequency and ultrasonic amplitude of the cable under test when the second control module sends an ultrasonic signal test command, and to determine whether the cable under test has partial discharge based on the difference between the ultrasonic frequency and the preset ultrasonic frequency amplitude. The input terminal of the ultrasonic signal detection module is electrically connected to the output terminal of the detection module.

7. The partial discharge detection system for self-powered cables according to claim 6, characterized in that, The ultrasonic signal detection module includes an ultrasonic sensor.

8. The partial discharge detection system for self-powered cables according to claim 2, characterized in that, The judgment module also includes: The optical signal detection module is used to acquire the number of photons in the cable under test when the third control module sends an optical signal test command, and to determine whether the cable under test is partially discharged based on the difference between the number of photons and the preset number of photons. The input terminal of the optical signal detection module is electrically connected to the output terminal of the detection module.

9. The partial discharge detection system for self-powered cables according to claim 8, characterized in that, The optical signal detection module includes an ultraviolet light sensor.

10. A method for detecting partial discharge in self-powered cables, characterized in that, include: Extract preset signals, which include preset electrical signals, preset ultrasonic signals, and preset optical signals; The actual electrical signal, actual ultrasonic signal, and actual optical signal of the cable under test are detected within a preset time. The presence of partial discharge in the cable under test is determined based on the difference between the actual electrical signal and the preset electrical signal, the difference between the actual ultrasonic signal and the preset ultrasonic signal, and the difference between the preset optical signal and the actual optical signal. When the light signal of the detection laser propagates in the sensing optical fiber laid along the cable under test, it interacts with the medium in the sensing optical fiber to generate backscattered light; the laser is emitted after an alarm signal is issued; the alarm signal includes an alarm signal issued when the difference between the actual temperature of the cable joint of the cable under test collected by a first temperature sensor installed on the cable under test and the ambient temperature around the cable under test collected by a second temperature sensor installed near the cable under test is greater than a first preset value, and an alarm signal issued when the grounding current of the metal sheath of the cable under test collected by a grounding current sensor installed on the cable under test is greater than a second preset value; The collected backscattered light signal is converted into an electrical signal to obtain a signal containing physical quantities along the cable under test, including temperature, strain, and vibration. Abnormal events occurring along the cable under test are identified based on pattern recognition algorithms. The support vector machine in the pattern recognition algorithm is used to extract the temperature, strain and vibration physical quantity information along the cable under test, identify the abnormal state of the cable under test, and locate the abnormal event by time difference. The location of the abnormal event is calculated by using the time and speed of light pulse propagation in optical fiber in optical time domain reflectometer technology.

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