Cable joint abnormal discharge monitoring system and method

Abstract

The invention relates to a cable joint abnormal discharge monitoring system and method, the system comprises filling devices, a communication optical fiber, a sensing optical fiber and a distributed sound wave sensing host, the filling devices comprise a primary filling device and a secondary filling device, and the filling devices are used for filling the cable joint with a sensitizing material; all joints of the cable are covered by the sensing optical fiber through the filling device; one end of the communication optical fiber is pulled out by the distributed sound wave sensing host, and the other end of the communication optical fiber is connected with the sensing optical fiber and used for monitoring optical signal transmission in the system; one end of the sensing optical fiber is connected with the communication optical fiber, and the other end of the sensing optical fiber is laid on a cable and a cable joint after being pulled out for sensing vibration of the cable joint; and the distributed sound wave sensing host is connected with the communication optical fiber and is used for detecting and demodulating signals and identifying abnormal discharge. According to the invention, high-precision cable joint abnormal discharge monitoring and intensity identification can be realized, and a guarantee is provided for cable power transmission safety.

Description

Technical Field

[0001] The present application relates to the field of cable monitoring, and in particular to a system and method for monitoring abnormal discharge of cable joints. Background Art

[0002] my country's power grid is spread all over the country. The losses caused during the transmission process waste a lot of electricity resources. This includes not only the losses caused by the cable transmission itself, but also the losses caused by abnormal discharge of cable joints. In order to avoid excessive losses, abnormal discharge of cable joints must be monitored and maintained on a daily basis.

[0003] Abnormal discharge of cable joints is mainly caused by suspended discharge due to loose iron cores and clamps. Electrical breakdown occurs in the air gap, and discharge can be completed in an instant. At this time, electrical energy will also be converted into heat energy in an instant. The gas in the discharge center will expand due to the heat energy and propagate outward through sound waves. This also means that abnormal discharge of cable joints is usually accompanied by abnormal vibrations. These vibration signals contain various frequency components and have a wide frequency band. Therefore, the vibration signals of cable joints are collected in real time, and by analyzing the vibration signals, it can be determined whether abnormal discharge occurs in the cable joints. Monitoring long-distance transmission cables not only requires distributed sensors, but also traditional electrical sensors are susceptible to electromagnetic interference due to the discharge phenomenon, so there is currently no better means to monitor them.

[0004] In response to the requirements of long-distance, real-time, high-precision and anti-electromagnetic interference in cable monitoring tasks, distributed fiber optic sensing technology has attracted widespread attention due to its unique advantages. It can not only work normally under high-voltage conditions, but also realize long-distance and real-time cable monitoring tasks. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a cable joint abnormal discharge monitoring system and method, which can perform high-precision identification and positioning of abnormal discharges of multiple cables on one system, reduce the losses caused by abnormal discharges of cable joints, and reduce safety accidents.

[0006] To achieve the above objectives, this application provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a cable joint abnormal discharge monitoring system, including a filling device, a communication optical fiber, a sensing optical fiber, and a distributed acoustic wave sensing host.

[0008] The filling device is divided into a primary filling device and a secondary filling device, which are used to fill the sensitization material at the cable joints, and the sensing optical fiber covers all the joints of the cable through the filling device;

[0009] One end of the communication optical fiber is pulled out by the distributed acoustic wave sensor host, and the other end is connected to the sensing optical fiber for monitoring the transmission of optical signals inside the system;

[0010] One end of the sensing optical fiber is connected to the communication optical fiber, and the other end is pulled out and laid on the cable and the cable joint to sense the vibration of the cable joint;

[0011] The distributed acoustic wave sensor host is connected to the communication optical fiber and is used for signal detection, demodulation and abnormal discharge identification.

[0012] The one-time filling device comprises a shaped shell, a rotating shaft, a threaded convex groove and a filling port. The shaped shell is formed by two symmetrical shaped containers connected by a rotating shaft. The inner side of the shaped container has a spiral pattern convex outward. One of the shaped containers is fixed on the cable along the central axis, and the shaped shell is buckled by the rotating shaft. The two ends of the one-time filling device are hollow conical barrels, and the middle section is a hollow cylindrical barrel.

[0013] The secondary filling device comprises a packaging shell, a connecting shaft and an injection port. The shaping shell is formed by connecting two symmetrical packaging containers through the connecting shaft. The secondary filling device is in the shape of a cylindrical barrel.

[0014] The distributed acoustic wave sensor host includes a data acquisition module, a feature processing module, a cable abnormal discharge determination module, and an abnormal discharge positioning module.

[0015] The data acquisition module is used to collect abnormal vibration signals of cable joints output by the distributed acoustic wave sensor host, and send the signals to the feature processing module;

[0016] The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data collection module, removes redundant information of the original signal, and extracts the most significant signal features;

[0017] The cable abnormal discharge determination module receives data from the feature processing module, determines in real time whether the signal feature has changed and the degree of change, thereby determining whether abnormal discharge occurs at the cable joint and the discharge intensity. When it is determined to be abnormal, an alarm is issued and the abnormal data is input into the abnormal discharge positioning module;

[0018] The abnormal discharge positioning module, upon receiving the abnormal data from the cable abnormal discharge determination module, obtains the index of the abnormal filling device and locates the abnormal discharge position of the cable according to the index.

[0019] In a second aspect, an embodiment of the present application provides a method for monitoring abnormal discharge of a cable joint, comprising the following steps:

[0020] Cover all the joints of the cable with the sensing optical fiber through the filling device;

[0021] The data acquisition module collects the abnormal vibration signal of the cable joint output by the distributed acoustic wave sensor host, and sends the signal to the feature processing module;

[0022] The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data acquisition module, removes redundant information of the original signal, and extracts the most significant signal features;

[0023] The cable abnormal discharge determination module receives data from the feature processing module and determines in real time whether the signal feature has changed and the degree of change, so as to determine whether abnormal discharge occurs at the cable joint and the discharge intensity. If it is determined to be abnormal, an alarm is issued and the abnormal data is input into the abnormal discharge positioning module;

[0024] After receiving the abnormal data from the cable abnormal discharge determination module, the abnormal discharge positioning module obtains the index of the abnormal filling device and locates the abnormal discharge position of the cable according to the index.

[0025] The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data collection module, removes redundant information of the original signal, and extracts the most significant signal features, specifically,

[0026] Each cable joint is equipped with a sensor enhancement structure. The i-th cable joint corresponds to the i-th optical fiber sensing channel. The signal characteristics F at each cable joint are calculated separately. i As a reference value:

[0027] F i =f 1 *f 2 *f 3

[0028] where f 1 is the average amplitude of the signal, as feature 1:

[0029]

[0030] where e i is the time domain signal amplitude corresponding to the i-th data point in the signal, and A is the total number of sampling points of the signal;

[0031] f 2 is the center-of-gravity frequency of the signal, as feature 2:

[0032]

[0033] where f k is the frequency amplitude corresponding to the kth data point in the signal, and P(k) is the power spectrum of the signal;

[0034] f 3 is the number of peaks of the signal, as feature 3:

[0035] where f 3 The value is that the amplitude of the data point in the signal is greater than or equal to 2*f 1 The number of

[0036] When the cable joint is in operation, the signal characteristics F of the cable joint when it is in normal operation are continuously compared. i1 and the signal characteristics F during cable operation i2 :

[0037]

[0038] When more than 5 consecutive measurement cycles are performed, S i >110%, it is considered that abnormal discharge occurs at the cable joint;

[0039] When the cable connector F is detected i After abnormal discharge occurs, the location where the abnormal discharge occurs is the i-th cable joint.

[0040] Compared with the prior art, the beneficial effects of the present invention are: it can realize high-precision abnormal discharge monitoring and strength identification of cable joints, and provide guarantee for the safety of cable power transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 This is a diagram of the abnormal discharge monitoring system for cable joints;

[0043] Figure 2 It is a diagram of a one-time filling device;

[0044] Figure 3 It is a secondary filling device;

[0045] Figure 4 It is a method flow chart. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0047] The terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0048] The terms "first", "second", etc. are only used to distinguish one entity or operation from another entity or operation, and should not be understood as indicating or implying relative importance, nor should they be understood as requiring or implying any such actual relationship or order between these entities or operations.

[0049] like Figure 1 As shown, the embodiment of the present application provides a cable joint abnormal discharge monitoring system, including a filling device 1, a communication optical fiber 2, a sensing optical fiber 3 and a distributed acoustic wave sensor host 4.

[0050] The filling device 1 is divided into a primary filling device 10 and a secondary filling device 20, which are used to fill the sensitization material at the joints of the cable 5, and the sensing optical fiber covers all the joints of the cable 5 through the filling device;

[0051] One end of the communication optical fiber 2 is pulled out by the distributed acoustic wave sensor host 4, and the other end is connected to the sensing optical fiber 3 for monitoring the transmission of optical signals inside the system;

[0052] One end of the sensing optical fiber 3 is connected to the communication optical fiber 2, and the other end is pulled out and laid on the cable 5 and the cable connector to sense the vibration of the cable connector;

[0053] The distributed acoustic wave sensor host 4 is connected to the communication optical fiber and is used for signal detection, demodulation and abnormal discharge identification.

[0054] like Figure 2 As shown, the one-time filling device 10 includes a shaped shell 11, a rotating shaft 12, a threaded groove 13 and a filling port 14. The shaped shell 11 is formed by two symmetrical shaped containers connected by a rotating shaft. The inner side of the shaped container has a spiral pattern convex outward. One of the shaped containers is fixed on the cable along the central axis, and the shaped shell 11 is buckled by the rotating shaft 12. The two ends of the one-time filling device are hollow conical barrels, and the middle section is a hollow cylindrical barrel.

[0055] like Figure 3 As shown, the secondary filling device 20 includes a packaging shell 21, a connecting shaft 22 and an injection port 23. The molding shell 21 is formed by two symmetrical packaging containers connected by a connecting shaft, and the secondary filling device is in the shape of a cylindrical barrel.

[0056] The distributed acoustic wave sensor host includes a data acquisition module, a feature processing module, a cable abnormal discharge determination module, and an abnormal discharge positioning module.

[0057] The data acquisition module is used to collect abnormal vibration signals of cable joints output by the distributed acoustic wave sensor host, and send the signals to the feature processing module;

[0058] The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data collection module, removes redundant information of the original signal, and extracts the most significant signal features;

[0059] The cable abnormal discharge determination module receives data from the feature processing module, determines in real time whether the signal feature has changed and the degree of change, thereby determining whether abnormal discharge occurs at the cable joint and the discharge intensity. When it is determined to be abnormal, an alarm is issued and the abnormal data is input into the abnormal discharge positioning module;

[0060] The abnormal discharge positioning module, upon receiving the abnormal data from the cable abnormal discharge determination module, obtains the index of the abnormal filling device and locates the abnormal discharge position of the cable according to the index.

[0061] like Figure 4 The present invention provides a method for monitoring abnormal discharge of a cable joint, comprising the following steps:

[0062] Cover all the joints of the cable with the sensing optical fiber through the filling device;

[0063] The data acquisition module collects the abnormal vibration signal of the cable joint output by the distributed acoustic wave sensor host, and sends the signal to the feature processing module;

[0064] The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data acquisition module, removes redundant information of the original signal, and extracts the most significant signal features;

[0065] The cable abnormal discharge determination module receives data from the feature processing module and determines in real time whether the signal feature has changed and the degree of change, so as to determine whether abnormal discharge occurs at the cable joint and the discharge intensity. If it is determined to be abnormal, an alarm is issued and the abnormal data is input into the abnormal discharge positioning module;

[0066] After receiving the abnormal data from the cable abnormal discharge determination module, the abnormal discharge positioning module obtains the index of the abnormal filling device and locates the abnormal discharge position of the cable according to the index.

[0067] The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data collection module, removes redundant information of the original signal, and extracts the most significant signal features, specifically,

[0068] Each cable joint is equipped with a sensor enhancement structure. The i-th cable joint corresponds to the i-th optical fiber sensing channel. The signal characteristics F at each cable joint are calculated separately. i As a reference value:

[0069] F i =f 1 *f 2 *f 3

[0070] where f 1 is the average amplitude of the signal, as feature 1:

[0071]

[0072] where e i is the time domain signal amplitude corresponding to the i-th data point in the signal, and A is the total number of sampling points of the signal;

[0073] f 2 is the center-of-gravity frequency of the signal, as feature 2:

[0074]

[0075] where f k is the frequency amplitude corresponding to the kth data point in the signal, and P(k) is the power spectrum of the signal;

[0076] f 3 is the number of peaks of the signal, as feature 3:

[0077] where f 3 The value is that the amplitude of the data point in the signal is greater than or equal to 2*f 1 The number of

[0078] When the cable joint is in operation, the signal characteristics F of the cable joint when it is in normal operation are continuously compared. i1 and the signal characteristics F during cable operation i2 :

[0079]

[0080] When more than 5 consecutive measurement cycles are performed, S i >110%, it is considered that abnormal discharge occurs at the cable joint;

[0081] When the cable connector F is detected i After abnormal discharge occurs, the location where the abnormal discharge occurs is the i-th cable joint.

[0082] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cable joint abnormal discharge monitoring system, characterized in that: It includes a filling device, a communication optical fiber, a sensing optical fiber and a distributed acoustic wave sensing host. The filling device is divided into a primary filling device and a secondary filling device, which are used to fill the sensitization material at the cable joints, and the sensing optical fiber covers all the joints of the cable through the filling device; One end of the communication optical fiber is pulled out by the distributed acoustic wave sensor host, and the other end is connected to the sensing optical fiber for monitoring the transmission of optical signals inside the system; One end of the sensing optical fiber is connected to the communication optical fiber, and the other end is pulled out and laid on the cable and the cable joint to sense the vibration of the cable joint; The distributed acoustic wave sensor host is connected to the communication optical fiber and is used for signal detection, demodulation and abnormal discharge identification.

2. A cable joint abnormal discharge monitoring system according to claim 1, characterized in that: The one-time filling device comprises a shaped shell, a rotating shaft, a threaded convex groove and a filling port. The shaped shell is formed by two symmetrical shaped containers connected by a rotating shaft. The inner side of the shaped container has a spiral pattern convex outward. One of the shaped containers is fixed on the cable along the central axis, and the shaped shell is buckled by the rotating shaft. The two ends of the one-time filling device are hollow conical barrels, and the middle section is a hollow cylindrical barrel.

3. A cable joint abnormal discharge monitoring system according to claim 1, characterized in that: The secondary filling device comprises a packaging shell, a connecting shaft and an injection port. The shaping shell is formed by connecting two symmetrical packaging containers through the connecting shaft. The secondary filling device is in the shape of a cylindrical barrel.

4. A cable joint abnormal discharge monitoring system according to claim 1, characterized in that: The distributed acoustic wave sensor host includes a data acquisition module, a feature processing module, a cable abnormal discharge determination module, and an abnormal discharge positioning module. The data acquisition module is used to collect abnormal vibration signals of cable joints output by the distributed acoustic wave sensor host, and send the signals to the feature processing module; The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data collection module, removes redundant information of the original signal, and extracts the most significant signal features; The cable abnormal discharge determination module receives data from the feature processing module, determines in real time whether the signal feature has changed and the degree of change, thereby determining whether abnormal discharge occurs at the cable joint and the discharge intensity. When it is determined to be abnormal, an alarm is issued and the abnormal data is input into the abnormal discharge positioning module; The abnormal discharge positioning module, upon receiving the abnormal data from the cable abnormal discharge determination module, obtains the index of the abnormal filling device and locates the abnormal discharge position of the cable according to the index.

5. A method for monitoring abnormal discharge of a cable joint, characterized in that: The following steps are involved: Cover all the joints of the cable with the sensing optical fiber through the filling device; The data acquisition module collects the abnormal vibration signal of the cable joint output by the distributed acoustic wave sensor host, and sends the signal to the feature processing module; The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data acquisition module, removes redundant information of the original signal, and extracts the most significant signal features; The cable abnormal discharge determination module receives data from the feature processing module and determines in real time whether the signal feature has changed and the degree of change, so as to determine whether abnormal discharge occurs at the cable joint and the discharge intensity. If it is determined to be abnormal, an alarm is issued and the abnormal data is input into the abnormal discharge positioning module; After receiving the abnormal data from the cable abnormal discharge determination module, the abnormal discharge positioning module obtains the index of the abnormal filling device and locates the abnormal discharge position of the cable according to the index.

6. A cable joint abnormal discharge monitoring method according to claim 5, characterized in that: The feature processing module performs data processing and feature extraction on the abnormal vibration signal collected by the data collection module, removes redundant information of the original signal, and extracts the most significant signal features, specifically, Each cable joint is equipped with a sensor enhancement structure. The i-th cable joint corresponds to the i-th optical fiber sensing channel. The signal characteristics F at each cable joint are calculated separately. i As a reference value: <h2 style=";text-align:left;direction:ltr">F<h2 style=";text-align:left;direction:ltr"> i <h2 style=";text-align:left;direction:ltr"> =f1*f2*f3 Where f1 is the average amplitude of the signal, as feature 1: where e i is the time domain signal amplitude corresponding to the i-th data point in the signal, and A is the total number of sampling points of the signal; f2 is the center frequency of the signal, as feature 2: where f k is the frequency amplitude corresponding to the kth data point in the signal, and P(k) is the power spectrum of the signal; f3 is the number of peaks of the signal, as feature 3: The value of f3 is the number of data points in the signal whose amplitude is greater than or equal to 2*f1.

7. A cable joint abnormal discharge monitoring method according to claim 6, characterized in that: When the cable joint is in operation, the signal characteristics F of the cable joint when it is in normal operation are continuously compared. i1 and the signal characteristics F during cable operation i2 : When more than 5 consecutive measurement cycles are performed, S i >110%, it is considered that abnormal discharge occurs at the cable joint; When the cable connector F is detected i After abnormal discharge occurs, the location where the abnormal discharge occurs is the i-th cable joint.

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