Partial discharge detection system and method for self-energy-taking cable

Abstract

The invention relates to the field of cable partial discharge detection, in particular to a partial discharge detection system and method for a self-energy-taking cable. Under the condition that multiple judgment bases are obtained, whether partial discharge happens to the cable to be detected or not can be judged more comprehensively, and the reliability and objectivity of cable partial discharge detection results are improved. The partial discharge detection system for the self-energy-taking cable is characterized in that a preset signal extraction module extracts a preset signal, and the preset signal comprises at least one of a preset electric signal, a preset ultrasonic signal and a preset optical signal; the detection module detects at least one of an actual electric signal, an actual ultrasonic signal and an actual optical signal of the to-be-detected cable within a preset time; the judgment module judges whether the to-be-detected cable is subjected to partial discharge or not according to at least one of the difference value between the actual electric signal and the preset electric signal, the difference value between the actual ultrasonic signal and the preset ultrasonic signal and the difference value between the preset optical signal and the actual optical signal of the to-be-detected cable.

Description

Technical Field

[0001] The present application relates to the field of cable partial discharge detection, and in particular to a partial discharge detection system and method for self-powered cables. Background Art

[0002] With the acceleration of urbanization, the demand for electricity continues to grow. As the main carrier of urban power supply, the safety and stability of the cable under test are crucial to the normal operation of the city. The cable under test may encounter various faults during operation, which may cause power outages and fires. Therefore, real-time fault monitoring of the cable under test is of great practical significance. Detecting whether the cable has partial discharge, harmonic current and other characteristic quantities is important monitoring information to identify whether the cable under test has a fault.

[0003] However, in the traditional cable partial discharge detection technology, it is impossible to accurately obtain the detection results of partial discharge in the cable under test. There are problems such as low detection accuracy, and the detection results are not comprehensive and objective, resulting in 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 occurs in the cable to be tested, and improve the reliability and comprehensiveness of the cable partial discharge detection results. To achieve the purpose of this application, this application provides the following technical solutions:

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

[0006] A preset signal extraction module, 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] A detection module, used to detect at least one of an actual electrical signal, an actual ultrasonic signal and an actual optical signal of the cable to be tested within a preset time;

[0008] A judgment module is used to judge whether the cable under test has partial discharge based on at least one of the difference between the actual electrical signal of the cable under test 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. The input end of the judgment module is electrically connected to the output end of the preset signal extraction module and the output end of the detection module.

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

[0010] Also includes:

[0011] a first control module, configured to send a first test instruction, and control the detection module to detect an actual electrical signal of the cable to be tested according to the first test instruction, wherein the test instruction includes at least one of a pulse signal test instruction, a current test instruction, and a voltage test instruction, and an output end of the first control module is electrically connected to an input end of the detection module;

[0012] a second control module, used for sending a second test instruction, and controlling the detection module to detect an actual ultrasonic signal of the cable to be tested according to the second test instruction, wherein an output end of the second control module is electrically connected to an input end of the detection module;

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

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

[0015] a first electrical signal judgment module, used for obtaining a 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 instruction, and judging whether the cable under test has partial discharge according to a difference between the pulse matching value and a preset pulse matching value, wherein an input end of the first electrical signal judgment module is electrically connected to an output end of the detection module;

[0016] a second electrical signal judgment module, used for obtaining the current value of the cable to be tested, and judging whether the cable to be tested has partial discharge according to the difference between the current value and a preset current value, when the first control module sends a current signal test instruction, wherein the input end of the second electrical signal judgment module is electrically connected to the output end of the detection module;

[0017] The third electrical signal judgment module is used to obtain the voltage value of the cable to be tested and judge whether the cable to be tested has partial discharge according to the difference between the voltage value and a preset voltage value when the first control module sends a voltage signal test instruction. The input end of the third electrical signal judgment module is electrically connected to the output end of the detection module.

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

[0019] A pulse signal acquisition module, used to obtain frequency information, amplitude information and waveform length information of the pulse electrical signal of the cable to be tested within a preset time;

[0020] A calculation module is used to calculate the pulse matching value of the pulse electrical signal of the cable to be tested within a preset time according to the frequency information, the amplitude information and the waveform length information, the input end of the first judgment module is electrically connected to the output end of the pulse signal acquisition module, and the output end of the calculation module is electrically connected to the input end 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 obtain the ultrasonic frequency and ultrasonic amplitude of the cable to be tested when the second control module sends an ultrasonic signal test instruction, and to determine whether the cable to be tested has partial discharge based on the difference between the ultrasonic frequency and a preset ultrasonic frequency amplitude. The input end of the ultrasonic signal detection module is electrically connected to the output end of the detection module.

[0024] In one of the embodiments, 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 of the cable to be tested when the third control module sends an optical signal test instruction, and judge whether the cable to be tested has partial discharge according to 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] In a second aspect, the present application provides a partial discharge detection method for a self-powered cable, comprising:

[0029] Extracting a preset signal, wherein the preset signal includes a preset electrical signal, a preset ultrasonic signal, and a preset optical signal;

[0030] Detecting an actual electrical signal, an actual ultrasonic signal, and an actual optical signal of the cable to be tested within a preset time;

[0031] Whether the cable under test has partial discharge is determined according to the difference between the actual electrical signal of the cable under test 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 local discharge detection system and method for self-powered cables of the present application extracts a preset signal through a preset signal extraction module, and the preset signal includes at least one of a preset electrical signal, a preset ultrasonic signal, and a preset optical signal, so that the local discharge detection system for self-powered cables can obtain the judgment basis for judging whether local discharge occurs in the cable to be tested. Then, the detection module detects at least one of the actual electrical signal, the actual ultrasonic signal, and the actual optical signal of the cable to be tested within the preset time, and the discharge information of multiple detection dimensions of the cable to be tested within the preset time can be obtained, and the detection result is more comprehensive. Finally, the judgment module judges whether the cable to be tested has local discharge according to at least one of the difference between the actual electrical signal of the cable to be tested 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. In this way, it is possible to more comprehensively judge whether local discharge occurs in the cable to be tested when multiple judgment bases are obtained, thereby improving the reliability and objectivity of the cable local discharge detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] FIG1 is a schematic structural diagram of a partial discharge detection system for a self-powered cable provided in an embodiment of the present application;

[0035] FIG2 is a schematic structural diagram of another partial discharge detection system for a self-powered cable provided in an embodiment of the present application;

[0036] FIG3 is a schematic flow chart of a partial discharge detection method for a self-energy extraction cable provided in an embodiment of the present application.

[0037] Description of Reference Numerals

[0038] 10. Preset signal extraction module; 20. Detection module; 30. Judgment module; 301. First electric signal judgment module; 302. Second electric signal judgment module; 303. Third electric 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 DESCRIPTION

[0039] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0041] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "consisting of" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or parts can be determined, but the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups is not excluded. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0042] With the acceleration of urbanization, the demand for electricity continues to grow. As the main carrier of urban power supply, the safety and stability of the cable under test are crucial to the normal operation of the city. The cable under test may encounter various faults during operation, which may cause power outages and fires. Therefore, real-time fault monitoring of the cable under test is of great practical significance. Detecting whether the cable has partial discharge, harmonic current and other characteristic quantities is important monitoring information to identify whether the cable under test has a fault.

[0043] However, in the traditional cable partial discharge detection technology, it is impossible to accurately obtain the detection results of partial discharge in the cable under test. There are problems such as low detection accuracy, and the detection results are not comprehensive and objective, resulting in the risk of partial discharge in the cable under test.

[0044] The embodiment of the present application provides a partial discharge detection system for a self-energy cable, please refer to FIG1, the partial discharge detection system for a self-energy cable includes: a preset signal extraction module 10, a detection module 20 and a judgment module 30, the preset signal extraction module 10 is used to extract a preset signal, and the preset signal includes at least one of a preset electrical signal, a preset ultrasonic signal and a preset optical signal. The detection module 20 is used to detect at least one of the actual electrical signal, the actual ultrasonic signal and the actual optical signal of the cable under test within a preset time. The judgment module 30 is used to judge whether the cable under test is partially discharged according to at least one of the difference between the actual electrical signal of the cable under test 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. The input end of the judgment module 30 is electrically connected to the output end of the preset signal extraction module 10 and the output end of the detection module 20.

[0045] Exemplarily, the preset electrical signal, the preset ultrasonic signal and the preset optical signal can all be set according to actual conditions. Specifically, the preset electrical signal can include a preset pulse signal, a preset current signal and a preset voltage signal. The preset electrical signal, the preset ultrasonic signal and the preset optical signal are all electrical signals, ultrasonic signals and optical signals when partial discharge occurs in the cable under test. According to at least one of the difference between the actual electrical signal of the cable under test 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, it is possible to accurately determine whether the cable under test has partial discharge, thereby improving the reliability of the cable.

[0046] The local discharge detection system for self-powered cables of the present application extracts a preset signal through a preset signal extraction module 10, and the preset signal includes at least one of a preset electrical signal, a preset ultrasonic signal, and a preset optical signal, so that the local discharge detection system for self-powered cables can obtain the judgment basis for judging whether local discharge occurs in the cable to be tested. Then, the detection module 20 detects at least one of the actual electrical signal, the actual ultrasonic signal, and the actual optical signal of the cable to be tested within the preset time, and the discharge information of multiple detection dimensions of the cable to be tested within the preset time can be obtained, and the detection result is more comprehensive. Finally, the judgment module 30 judges whether the cable to be tested has local discharge according to at least one of the difference between the actual electrical signal of the cable to be tested 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. In this way, it can be more comprehensively judged whether local discharge occurs in the cable to be tested when multiple judgment bases are obtained, thereby improving the reliability and objectivity of the cable local discharge detection result.

[0047] In some embodiments, please continue to refer to Figure 2, which also includes: a first control module 40, used to send a first test instruction, and control the detection module 20 to detect the actual electrical signal of the cable to be tested according to the first test instruction, wherein the test instruction includes at least one of a pulse signal test instruction, a current test instruction and a voltage test instruction, and the output end of the first control module 40 is electrically connected to the input end of the detection module 20; a second control module 50, used to send a second test instruction, and control the detection module 20 to detect the actual ultrasonic signal of the cable to be tested according to the second test instruction, and the output end of the third control module 60 is electrically connected to the input end of the detection module 20; a third control module, used to send a third test instruction, and control the detection module 20 to detect the actual optical signal of the cable to be tested according to the third test instruction, and the output end of the third control module is electrically connected to the input end 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 the first test instruction, the second test instruction and the third test instruction according to the test requirements to control the detection module 20 to detect the actual electrical signal, the actual ultrasonic signal and the actual optical signal of the cable to be tested. Specifically, the first control module 40, the second control module 50 and the third control module 60 can select to send the first test instruction, the second test instruction and the third test instruction 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-energy cables in the embodiment of the present application can send the first test instruction, the second test instruction and the third test instruction according to the test requirements to control the detection module 20 to detect the actual electrical signal, the actual ultrasonic signal and the actual optical signal of the cable to be tested, through the first control module 40, the second control module 50 and the third control module 60, 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 to refer to Figure 2, the judgment module 30 includes: a first electrical signal judgment module 301, which is used to obtain the pulse matching value of the pulse electrical signal of the cable to be tested within a preset time when the first control module 40 sends a pulse signal test instruction, and judge whether the cable to be tested is partially discharged according to the difference between the pulse matching value and the preset pulse matching value. The input end of the first electrical signal judgment module 301 is electrically connected to the output end of the detection module 20; a second electrical signal judgment module 302, which is used to obtain the current value of the cable to be tested when the first control module 40 sends a current signal test instruction, and judge whether the cable to be tested is partially discharged according to the difference between the current value and the preset current value. The input end of the second electrical signal judgment module 302 is electrically connected to the output end of the detection module 20; a third electrical signal judgment module 303, which is used to obtain the voltage value of the cable to be tested when the first control module 40 sends a voltage signal test instruction, and judge whether the cable to be tested is partially discharged according to the difference between the voltage value and the preset voltage value. The input end of the third electrical signal judgment module 303 is electrically connected to the output end 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 to be tested within a preset time when the first control module 40 sends a pulse signal test instruction. Specifically, the pulse electrical signal of the cable to be tested within a preset time can be obtained by installing an induction coil in the circumference of the cable to be tested.

[0052] In another example, a discharge current sensor can be installed on the cable to be tested to collect the current value of the cable to be tested, and the current value of the cable to be tested is a pulse current signal released due to partial discharge of the cable to be tested. Further, the second electrical signal judgment module 302 judges whether the cable to be tested has partial discharge by the difference between the current value of the cable to be tested and the preset current value. More specifically, after collecting the current value of the cable to be tested, the current value of the cable to be tested can be filtered to obtain a current signal that is easier to judge whether there is partial discharge.

[0053] In yet another example, a voltage sensor may be installed on the cable to be tested to collect the voltage value of the cable to be tested. More specifically, if the voltage value is not 0, partial discharge occurs in the cable to be tested.

[0054] The partial discharge detection system for self-energy cables in the embodiment of the present application can more comprehensively detect whether partial discharge occurs in the cable to be tested by setting up an induction coil, a current sensor and a voltage sensor, so as to avoid the problem of low reliability of the detection results caused by incomplete detection.

[0055] In some embodiments, please continue to refer to Figure 2. The local discharge detection system for self-energy cables also includes: a pulse signal acquisition module 304, which is used to obtain the frequency information, amplitude information and waveform length information of the pulse electrical signal of the cable to be tested within a preset time; a calculation module 305, which is used to calculate the pulse matching value of the pulse electrical signal of the cable to be tested within a preset time based on the frequency information, amplitude information and waveform length information. The input end of the first judgment module 30 is electrically connected to the output end of the pulse signal acquisition module 304, and the output end of the calculation module 305 is electrically connected to the input end of the first electrical signal judgment module 301.

[0056] As an example, the calculation module 305 can compare the pulse frequency interval with the preset pulse frequency interval. The preset pulse frequency is the pulse frequency interval of the cable when no partial discharge occurs. In this way, the number of frequency overlaps between the actual pulse frequency of the cable under test and the preset pulse frequency within the preset time and the number of integer pulse frequencies of partial discharge can be obtained, so as to obtain the frequency consistency. The intensity coefficient is further calculated by 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 local discharge signal; v(j) is the amplitude of the j-th pulse signal; v(j-1) is the amplitude of the j-1-th pulse signal. Further, according to the waveform curve and the waveform curves of the pulse signals received within the preset time period are sequentially imported into the same coordinate system of the CAD software, the waveform curve length of the pulse signals received within the preset time period is obtained, and the average waveform curve length is calculated; after all the waveform curves of the pulse signals received within the preset time period are imported into the same coordinate system of the CAD software, a superposition analysis is performed to obtain the overall waveform coincidence curve length; the ratio of the overall waveform coincidence curve length to the average waveform curve length is calculated to obtain the waveform law consistency, and based on the frequency consistency, the intensity coefficient and the waveform law consistency, the pulse matching value is calculated. Specifically, the pulse matching value can be calculated according to the following formula:

[0059]

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

[0061] The partial discharge detection system for self-energy cables in the embodiment of the present application calculates the pulse matching value by frequency matching, intensity coefficient and waveform matching, so as to obtain the actual pulse signal of the cable to be tested more accurately, correct the subjective and incomplete detection results of the pulse signal, and improve the accuracy of the pulse signal detection of the cable to be tested.

[0062] In some embodiments, please continue to refer to FIG. 2 , the pulse signal acquisition module 304 includes a discharge induction coil.

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

[0064] The partial discharge detection system for self-energy cables in the embodiment of the present application obtains the pulse signal of the cable to be tested through an electric induction coil, can detect the pulse signal of the cable to be tested in a larger range, and can reduce ionization and chemical interference, and improve the accuracy and precision of the detection results.

[0065] In some embodiments, please continue to refer to Figure 2. The judgment module 30 also includes: an ultrasonic signal detection module 306, which is used to obtain the ultrasonic frequency and ultrasonic amplitude of the cable to be tested when the second control module 50 sends an ultrasonic signal test instruction, and judge whether the cable to be tested 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 obtains the ultrasonic frequency and ultrasonic amplitude of the cable to be tested, before judging whether the cable to be tested has partial discharge based on the difference between the ultrasonic frequency and the preset ultrasonic frequency amplitude, the ultrasonic frequency and ultrasonic amplitude can also be pre-processed by signal filtering and amplification.

[0067] In some embodiments, please continue to refer to FIG. 2 , the ultrasonic signal detection module 306 includes an ultrasonic sensor.

[0068] As an example, an ultrasonic sensor can convert electrical energy into mechanical vibrations to generate ultrasonic waves. When the ultrasonic waves encounter the object or medium being measured, they will cause reflection or refraction, and then the receiver will receive the echo. The receiver then converts the mechanical vibration of the echo into an electrical signal to detect the ultrasonic signal.

[0069] In the partial discharge detection system for self-energy cables in the embodiment of the present application, the ultrasonic sensor has the advantages of high frequency, high sensitivity, strong penetration, and the ability to detect external or deep objects. Therefore, more accurate ultrasonic detection signals can be obtained, thereby improving the accuracy and objectivity of the detection results.

[0070] In some embodiments, please continue to refer to Figure 2, the judgment module 30 also includes: an optical signal detection module 307, which is used to obtain the number of photons of the cable to be tested when the third control module 60 sends an optical signal test instruction, and judge whether the cable to be tested has partial discharge 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 obtains the number of photons of the cable under test and determines whether the cable under test has partial discharge according to the difference between the number of photons and a preset number of photons. Whether the cable under test has partial discharge can be determined by optical detection.

[0072] In some embodiments, please continue to refer to FIG. 2 , the optical signal detection module 307 includes an ultraviolet light sensor.

[0073] As an example, the ultraviolet light sensor can convert the ultraviolet light signal into an electrical signal through a photosensitive element, thereby obtaining the optical signal of the cable to be tested.

[0074] In the partial discharge detection system for self-energy cables in the embodiment of the present application, the ultraviolet light sensor has the advantages of high sensitivity, high output, high response speed, etc., and the ultraviolet light sensor has strong anti-interference ability and good stability. It can more comprehensively measure the optical signal of the cable to be tested and convert the detected optical signal into an electrical signal. The electrical signal can more intuitively determine whether partial discharge occurs in the cable to be tested, thereby improving the reliability and objectivity of the detection results.

[0075] It should be noted that the partial discharge detection system for self-energy cables in the embodiment of the present application may also include: a first temperature sensor, installed on the cable to be tested, for collecting the actual temperature of the cable connector of the cable to be tested. A second temperature sensor, installed near the cable to be tested, for collecting the ambient temperature around the cable to be tested. It is determined by whether the difference between the actual temperature and the ambient temperature is greater than a first preset value. If so, there is an abnormality in the cable to be tested, and an alarm signal is issued. Whether the operating state of the cable to be tested is abnormal can be determined by detecting the actual temperature at different positions of the cable connector and the ambient temperature around it. Compared with the method of determining whether the operating state of the cable to be tested is abnormal only by the cable temperature, the accuracy of temperature monitoring is effectively improved. More specifically, the alarm signal may include a sound alarm, a light alarm, or an audible and visual alarm.

[0076] It should be noted that the partial discharge detection system for self-energy cables in the embodiment of the present application may also include: a ground current sensor, which is installed on the cable to be tested and is used to collect the ground current of the metal sheath of the cable to be tested. When the ground current is greater than the second preset value, the cable to be tested is abnormal and an alarm signal is issued. Specifically, the ground current sensor can use a Rogowski coil. This embodiment monitors the ground current in real time. Once a fault occurs in the cable to be tested, the ground current will increase, that is, it will exceed the second preset value, and an alarm signal will be issued immediately, thereby improving the safety and reliability of the working cable.

[0077] It should be noted that the partial discharge detection system for self-energy cables in the embodiment of the present application may also include: a vibration sensor, which is installed on the cable to be tested and is used to collect the vibration signal of the cable to be tested. The signal characteristics of the vibration signal are compared with the signal characteristics under different working states to determine whether there is external force damage, and the signal characteristics include time domain characteristics and frequency domain characteristics. Specifically, in the database, the time domain characteristics and frequency domain characteristics of the vibration signal of the cable to be tested under different working states are saved, such as: the signal characteristics and thresholds of the cable in a normal quiet state, the signal characteristics and thresholds when people cut the cable with tools, the signal characteristics and thresholds when the engineering excavator touches the cable when working nearby, the signal characteristics and thresholds when the cable is struck by lightning, etc. When a vibration signal is received, its signal characteristics are first compared with the signal characteristics and thresholds in the normal quiet state in the database. If it exceeds the threshold range, it means that this is an abnormal vibration signal, and it can be determined that there is external force damage, and further compared with the signal characteristics and thresholds of various abnormal situations in the database to determine what causes the external force damage, so as to determine 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-energy cables in the application embodiment sends out an alarm signal, the partial discharge detection system for self-energy cables in the application embodiment can also accurately locate the abnormal position of the cable to be tested. Specifically, the light source transmitting module emits a laser, and the sensing optical fiber is laid along the cable to be tested. When the optical signal propagates in the sensing optical fiber, it interacts with the medium in the sensing optical fiber to generate backscattered light. The optical time domain reflectometer technology is used to detect the backscattered light generated in the sensing optical fiber. The backscattered light contains physical quantity information along the cable. The collected backscattered light signal is converted into The electrical signal is used to obtain a signal containing physical quantities along the cable to be tested, including temperature, strain and vibration. The judgment module 30 identifies abnormal events occurring along the cable based on a pattern recognition algorithm, and uses a support vector machine in the pattern recognition algorithm to extract key features, such as temperature, strain and vibration physical quantity information along the cable, so as to accurately identify the abnormal state of the cable, and promptly discover and handle cable damage events, thereby improving the safety and stability of the power system. At the same time, through time difference positioning, the time and speed of light pulses propagating in the optical fiber in the optical time domain reflectometer technology are used to calculate the position of the abnormal event, thereby completing the fault location.

[0079] The embodiment of the present application also provides a partial discharge detection method for a self-powered cable, please refer to the figure, comprising:

[0080] S11: extracting a preset signal, where the preset signal includes a preset electrical signal, a preset ultrasonic signal and a preset optical signal.

[0081] S12: Detecting the actual electrical signal, the actual ultrasonic signal and the actual optical signal of the cable to be tested within a preset time.

[0082] S13: judging whether the cable under test has partial discharge according to the difference between the actual electrical signal of the cable under test 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 local discharge detection method for self-energy cables of the present application can obtain the judgment basis of the local discharge detection system for self-energy cables in judging whether local discharge occurs in the cable to be tested by extracting a preset signal, which includes at least one of a preset electrical signal, a preset ultrasonic signal and a preset optical signal. Then, at least one of the actual electrical signal, the actual ultrasonic signal and the actual optical signal of the cable to be tested within the preset time is detected, and the discharge information of multiple detection dimensions of the cable to be tested within the preset time can be obtained, and the detection result is more comprehensive. Finally, it is judged whether the cable to be tested has local discharge based on at least one of the difference between the actual electrical signal of the cable to be tested 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. In this way, it is possible to more comprehensively judge whether local discharge occurs in the cable to be tested when multiple judgment bases are obtained, thereby improving the reliability and objectivity of the cable local discharge detection results.

[0084] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features of the above-described 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 above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A partial discharge detection system for self-powered cables, characterized in that: include: A preset signal extraction module, 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; A detection module, used to detect at least one of an actual electrical signal, an actual ultrasonic signal and an actual optical signal of the cable to be tested within a preset time; A judgment module is used to judge whether the cable under test has partial discharge based on at least one of the difference between the actual electrical signal of the cable under test 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. The input end of the judgment module is electrically connected to the output end of the preset signal extraction module and the output end of the detection module.

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

3. The partial discharge detection system for self-powered cables according to claim 2, characterized in that: The judging module comprises: a first electrical signal judgment module, used for obtaining a 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 instruction, and judging whether the cable under test has partial discharge according to a difference between the pulse matching value and a preset pulse matching value, wherein an input end of the first electrical signal judgment module is electrically connected to an output end of the detection module; a second electrical signal judgment module, used for obtaining the current value of the cable to be tested, and judging whether the cable to be tested has partial discharge according to the difference between the current value and a preset current value, when the first control module sends a current signal test instruction, wherein the input end of the second electrical signal judgment module is electrically connected to the output end of the detection module; The third electrical signal judgment module is used to obtain the voltage value of the cable to be tested and judge whether the cable to be tested has partial discharge according to the difference between the voltage value and a preset voltage value when the first control module sends a voltage signal test instruction. The input end of the third electrical signal judgment module is electrically connected to the output end of the detection module.

4. The partial discharge detection system for self-powered cables according to claim 3, characterized in that: The judging module further includes: A pulse signal acquisition module, used to obtain frequency information, amplitude information and waveform length information of the pulse electrical signal of the cable to be tested within a preset time; A calculation module is used to calculate the pulse matching value of the pulse electrical signal of the cable to be tested within a preset time according to the frequency information, the amplitude information and the waveform length information, the output end of the calculation module is electrically connected to the input end of the first electrical signal judgment module, and the input end of the calculation module is electrically connected to the output end 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 judging module further includes: An ultrasonic signal detection module is used to obtain the ultrasonic frequency and ultrasonic amplitude of the cable to be tested when the second control module sends an ultrasonic signal test instruction, and to determine whether the cable to be tested has partial discharge based on the difference between the ultrasonic frequency and a preset ultrasonic frequency amplitude. The input end of the ultrasonic signal detection module is electrically connected to the output end 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 judging module further includes: The optical signal detection module is used to obtain the number of photons of the cable to be tested when the third control module sends an optical signal test instruction, and judge whether the cable to be tested has partial discharge according to the difference between the number of photons and a preset number of photons. The input end of the optical signal detection module is electrically connected to the output end 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 of a self-powered cable, characterized in that: include: Extracting a preset signal, wherein the preset signal includes a preset electrical signal, a preset ultrasonic signal, and a preset optical signal; Detecting an actual electrical signal, an actual ultrasonic signal, and an actual optical signal of the cable to be tested within a preset time; Whether the cable under test has partial discharge is determined according to the difference between the actual electrical signal of the cable under test 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.

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