GIS state monitoring system and method based on optical fiber sensing technology

Abstract

The invention relates to a GIS state monitoring system and method based on an optical fiber sensing technology, the system comprises a GIS cover plate, a temperature measurement module, a partial discharge measurement module and a state monitoring module, the temperature measurement module comprises a fiber bragg grating and is used for converting the temperature change of the GIS cover plate into a first optical signal in real time; the partial discharge measurement module comprises a distributed feedback fiber laser and is used for converting the vibration change of the GIS cover plate into a second optical signal in real time; the state monitoring module comprises a fiber bragg grating demodulator and a data processor, and the fiber bragg grating demodulator is used for receiving the first optical signal and the second optical signal and carrying out demodulation calculation to obtain a real-time temperature change value and a partial discharge vibration signal; the data processor compares and analyzes the temperature change value and the partial discharge vibration signal with a threshold value, and sends out a corresponding alarm signal if there is an abnormality. Compared with the prior art, the GIS internal temperature detection and partial discharge detection can be carried out at the same time, and high precision and sensitivity are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of high-voltage switchgear monitoring, and in particular relates to a GIS state monitoring system and method based on optical fiber sensing technology. Background Art

[0002] Gas insulated switchgear (GIS) is a high-voltage switchgear commonly used in power transmission and distribution systems. Compared with traditional air-insulated switchgear, GIS has the advantages of high insulation strength, small footprint, low operating cost and high reliability. However, due to factors such as parts quality, on-site installation and commissioning, and frequent operation, poor contact may occur at the internal conductor connection. In particular, switch equipment such as disconnectors are more prone to mechanical contact defects such as increased contact resistance. Such defects are the main cause of abnormal temperature rise inside GIS disconnectors. Under the action of operating current, once the disconnector has poor contact, it will cause abnormal temperature rise. The mechanical connection status of the GIS disconnector can be judged by temperature detection. However, the closed structural characteristics of GIS make these contact defects difficult to be detected in the early stage. Continuous defect development will cause serious equipment failure and cause economic and property losses. In addition, GIS is under load for a long time and the operating environment is relatively harsh, which is prone to partial discharge failure. Once a discharge failure occurs, it not only has a high probability of causing a fire accident, but also directly affects the stability and safety of the operation of the gas-insulated switchgear. Therefore, partial discharge detection of GIS is also very important for judging its operating status.

[0003] In response to the abnormal temperature rise problem of GIS, the traditional detection method is mainly through manual observation of the contact surface color or measurement of loop resistance, but both methods require power outage for maintenance, which greatly reduces the operating efficiency of the equipment. In view of the need for non-shutdown temperature monitoring, the methods for measuring temperature at key locations of GIS mainly include optical fiber temperature measurement, infrared thermal imaging temperature measurement, and infrared sensing temperature measurement. Among them, the optical fiber temperature measurement method directly lays the fiber grating temperature sensor at the key location of GIS for temperature measurement. It has the advantages of strong anti-electromagnetic interference ability and high reliability, but it also has problems such as low temperature measurement accuracy and complex sensor installation and layout scheme; the infrared thermal imaging temperature measurement method often uses an infrared imager to measure the overall temperature of the GIS shell to form a thermal distribution map, and extracts and calculates the temperature of key areas, but its temperature measurement accuracy is greatly affected by the external environment, and the accuracy and resolution are low.

[0004] In view of the partial discharge problem of GIS, the live detection methods are mainly divided into two categories: electrical detection method and non-electrical detection method. Electrical detection methods include pulse current detection, ultra-high frequency detection and other methods, and non-electrical detection methods include ultrasonic detection, optical detection, gas decomposition chemical composition detection and other methods. Among them, ultra-high frequency detection and ultrasonic detection are more widely used. However, in the ultra-high frequency detection method, the time difference of the signal is in the order of ns, which not only requires the measuring equipment to have a high sampling rate and bandwidth, but also requires the measured signal to have a clear starting pulse to read the starting time of the signal; but due to the complex structure inside the GIS equipment and the strong sound wave absorption rate of SF gas, the ultrasonic signal generated by partial discharge is often very weak when it is transmitted to the GIS shell. The sensitivity of traditional piezoelectric sensors is difficult to meet the detection requirements of weak sound wave signals of partial discharge. In addition, most of the existing GIS status monitoring solutions can only monitor one of abnormal temperature rise and partial discharge. Therefore, a GIS status monitoring solution needs to be redesigned. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a GIS status monitoring system and method based on optical fiber sensing technology, which can simultaneously perform GIS internal temperature detection and partial discharge detection with high accuracy and sensitivity.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides a GIS state monitoring system based on optical fiber sensing technology, comprising a GIS cover plate, a temperature measurement module, a partial discharge measurement module and a state monitoring module;

[0008] Wherein, the temperature measurement module includes a fiber Bragg grating, and the fiber Bragg grating is used to convert the temperature change of the GIS cover plate into a first optical signal in real time; the partial discharge measurement module includes a distributed feedback fiber laser, and the distributed feedback fiber laser is used to convert the vibration change of the GIS cover plate into a second optical signal in real time; the fiber Bragg grating and the distributed feedback fiber laser are both fixed on the cantilever beam of the GIS cover plate;

[0009] The state monitoring module includes a fiber Bragg grating demodulator and a data processor. The fiber Bragg grating demodulator is connected to the fiber Bragg grating and the distributed feedback fiber laser, respectively, and is used to receive the first optical signal and the second optical signal and perform demodulation calculations to obtain real-time temperature change values ​​and partial discharge vibration signals; the data processor is used to compare the real-time temperature change value with a preset first threshold value, and if it exceeds the first threshold value, a first alarm signal is issued. The data processor is also used to analyze and process the real-time partial discharge vibration signal to determine whether there is a partial discharge phenomenon, and if so, a second alarm signal is issued.

[0010] Furthermore, the fiber Bragg grating and the distributed feedback fiber laser are fixed on the cantilever beam of the GIS cover plate by gluing through colloid.

[0011] Furthermore, the colloid is epoxy resin.

[0012] Furthermore, the fiber Bragg grating and the distributed feedback fiber laser are connected to the fiber Bragg grating demodulator via optical fibers.

[0013] Furthermore, the optical fiber passes through a flange on the GIS cover plate.

[0014] The present invention also provides a GIS status monitoring method based on optical fiber sensing technology based on the above-mentioned GIS status monitoring system based on optical fiber sensing technology, comprising the following steps:

[0015] S1, fix the fiber Bragg grating and distributed feedback fiber laser on the cantilever beam of the GIS cover;

[0016] S2, converting the temperature change of the GIS cover plate into a first optical signal in real time through a fiber Bragg grating, and converting the vibration change of the GIS cover plate into a second optical signal in real time through a distributed feedback fiber laser;

[0017] S3, receiving the first optical signal and the second optical signal and performing demodulation calculation to obtain a real-time temperature change value and a partial discharge vibration signal;

[0018] S4. Compare the real-time temperature change value with a preset first threshold value. If it exceeds the first threshold value, a first alarm signal is issued; analyze and process the real-time partial discharge vibration signal to determine whether there is a partial discharge phenomenon. If so, a second alarm signal is issued.

[0019] Furthermore, in step S1, the fiber Bragg grating and the distributed feedback fiber laser are fixed on the cantilever beam of the GIS cover plate by gluing with colloid.

[0020] Furthermore, in step S4, the specific process of analyzing and processing the real-time partial discharge vibration signal is as follows:

[0021] S401, after preprocessing the real-time partial discharge vibration signal, extracting time domain features and frequency domain features, the time domain features include the amplitude, duration, rise time and fall time of the partial discharge vibration signal, and the frequency domain features include the frequency component, bandwidth and main frequency of the partial discharge vibration signal;

[0022] S402: Using a machine learning algorithm to identify and classify the time domain features and the frequency domain features to determine whether there is a partial discharge phenomenon.

[0023] Furthermore, in step S401, the preprocessing includes a cleaning step and a noise reduction step, and the noise reduction step uses wavelet transform, Fourier transform or Kalman filter.

[0024] Furthermore, in step S402, the machine learning algorithm includes support vector machine, random forest and deep neural network.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention proposes a GIS state monitoring system based on optical fiber sensing technology, including a GIS cover, a temperature measurement module, a partial discharge measurement module and a state monitoring module, wherein the temperature measurement module includes a fiber Bragg grating, which has the advantages of high temperature measurement sensitivity, anti-electromagnetic interference, small size, light weight, etc., and can convert the temperature change of the GIS cover into a first optical signal in real time; the partial discharge measurement module includes a distributed feedback fiber laser, and partial discharge will generate vibration. The distributed feedback fiber laser has the advantages of narrow output line width, high detection sensitivity, and small size, etc., and can convert the vibration change of the GIS cover into a first optical signal in real time. The state monitoring module includes a fiber grating demodulator and a data processor. The fiber grating demodulator receives the first optical signal and the second optical signal and performs demodulation calculation to obtain a real-time temperature change value and a partial discharge vibration signal. The data processor compares the real-time temperature change value with a preset first threshold value. If the temperature exceeds the first threshold value, a first alarm signal is issued. The data processor can also analyze and process the real-time partial discharge vibration signal to determine whether there is a partial discharge phenomenon. If so, a second alarm signal is issued. Through the above system, the real-time state of the GIS can be sensitively perceived, and early warnings can be issued in time for abnormal temperature rise and partial discharge problems.

[0027] 2. In the present invention, the fiber Bragg grating and the distributed feedback fiber laser are fixed on the cantilever beam of the GIS cover plate, and are connected to the fiber Bragg grating demodulator through optical fiber. The GIS temperature and partial discharge detection are performed through optical fiber sensing technology, which has the advantages of anti-electromagnetic interference, high sensitivity, and small size. The optical fiber passes through the flange on the GIS cover plate, and the structure of the GIS cover plate itself can be used to fix the optical fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the structure of the system of the present invention,

[0029] Explanation of the reference numerals: 1. GIS cover plate; 2. Fiber Bragg grating; 3. Distributed feedback fiber laser; 4. Fiber Bragg grating demodulator. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0031] Example 1

[0032] This embodiment provides a GIS status monitoring system based on optical fiber sensing technology. Figure 1 As shown, it includes a GIS cover plate 1, a temperature measurement module, a partial discharge measurement module and a status monitoring module.

[0033] The temperature measurement module includes a fiber Bragg grating 2, which has the advantages of high temperature measurement sensitivity, anti-electromagnetic interference, small size, light weight, etc. It can convert the temperature change of the GIS cover plate 1 into a first optical signal in real time.

[0034] The partial discharge measurement module includes a distributed feedback fiber laser 3. The distributed feedback fiber laser (DFB-FL) has the advantages of narrow output beam width, high detection sensitivity, and small size, and can convert the vibration change of the GIS cover plate 1 into a second optical signal in real time. Compared with the interferometric fiber sensor, the sensing unit and demodulation system of the distributed feedback fiber laser are independent of each other, which is conducive to long-distance monitoring of power equipment; compared with the Fabry-Perot fiber sensor, the distributed feedback fiber laser has a fully insulating structure and broadband detection characteristics, which is conducive to capturing more complete partial discharge information in a high-voltage field environment.

[0035] The fiber Bragg grating 2 and the distributed feedback fiber laser 3 are fixed to the cantilever beam of the GIS cover plate 1 by gluing with a colloid. In a preferred embodiment, the colloid is epoxy resin, which has good heat resistance and electrical insulation.

[0036] The state monitoring module includes a fiber Bragg grating demodulator 4 and a data processor. The fiber Bragg grating demodulator 4 is connected to the fiber Bragg grating 2 and the distributed feedback fiber laser 3 through optical fibers, receives the first optical signal and the second optical signal and performs demodulation calculation to obtain real-time temperature change values ​​and partial discharge vibration signals. In a preferred embodiment, the optical fiber passes through the flange on the GIS cover 1, and the optical fiber is fixed by the structure of the GIS cover itself. The data processor can compare the real-time temperature change value obtained by demodulation with a preset first threshold value. If it exceeds the first threshold value, a first alarm signal is issued; at the same time, the real-time partial discharge vibration signal can also be analyzed and processed to determine whether there is a partial discharge phenomenon. If so, a second alarm signal is issued.

[0037] The above system uses optical fiber sensing technology to detect GIS temperature and partial discharge, and can issue timely warnings for abnormal temperature rise and partial discharge problems. It has the advantages of anti-electromagnetic interference, high sensitivity and small size.

[0038] Example 2

[0039] This embodiment provides a GIS status monitoring method based on optical fiber sensing technology based on the system described in Embodiment 1, comprising the following steps:

[0040] S1. Fix the fiber Bragg grating 2 and the distributed feedback fiber laser 3 on the cantilever beam of the GIS cover plate 1.

[0041] S2. The temperature change of the GIS cover plate 1 is converted into a first optical signal in real time through the fiber Bragg grating 2, and the vibration change of the GIS cover plate 1 is converted into a second optical signal in real time through the distributed feedback fiber laser 3.

[0042] S3, receiving the first optical signal and the second optical signal through the fiber Bragg grating demodulator 4 and performing demodulation calculation, demodulating to obtain the wavelength change caused by the fiber Bragg grating and the distributed feedback fiber laser due to temperature and partial discharge, thereby obtaining real-time temperature change value and partial discharge vibration signal.

[0043] S4. Compare the real-time temperature change value with the preset first threshold value. If it exceeds the first threshold value, a first alarm signal is issued; analyze and process the real-time partial discharge vibration signal to determine whether there is a partial discharge phenomenon. If so, a second alarm signal is issued.

[0044] The specific process of analyzing and processing the real-time partial discharge vibration signal is as follows:

[0045] S401. Preprocess the real-time partial discharge vibration signal, which includes a cleaning step and a noise reduction step. The noise reduction step may use wavelet transform, Fourier transform or Kalman filter; extract time domain features (including amplitude, duration, rise time and fall time of the partial discharge vibration signal, etc.) and frequency domain features (including frequency components, bandwidth and main frequency of the partial discharge vibration signal, etc.) from the preprocessed data.

[0046] S402. Use machine learning algorithms (including support vector machines, random forests, and deep neural networks) to identify and classify time domain features and frequency domain features to determine whether there is a partial discharge phenomenon.

[0047] If the above method is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0048] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A GIS status monitoring system based on optical fiber sensing technology, characterized in that: It comprises a GIS cover plate (1), a temperature measurement module, a partial discharge measurement module and a status monitoring module; The temperature measurement module comprises a fiber Bragg grating (2), and the fiber Bragg grating (2) is used to convert the temperature change of the GIS cover plate (1) into a first optical signal in real time; the partial discharge measurement module comprises a distributed feedback fiber laser (3), and the distributed feedback fiber laser (3) is used to convert the vibration change of the GIS cover plate (1) into a second optical signal in real time; the fiber Bragg grating (2) and the distributed feedback fiber laser (3) are both fixed on the cantilever beam of the GIS cover plate (1); The state monitoring module comprises a fiber Bragg grating demodulator (4) and a data processor. The fiber Bragg grating demodulator (4) is connected to the fiber Bragg grating (2) and the distributed feedback fiber laser (3) respectively, and is used to receive the first optical signal and the second optical signal and perform demodulation calculation to obtain a real-time temperature change value and a partial discharge vibration signal. The data processor is used to compare the real-time temperature change value with a preset first threshold value, and if the first threshold value is exceeded, a first alarm signal is issued. The data processor is also used to analyze and process the real-time partial discharge vibration signal to determine whether a partial discharge phenomenon exists, and if so, a second alarm signal is issued.

2. A GIS status monitoring system based on optical fiber sensing technology according to claim 1, characterized in that: The fiber Bragg grating (2) and the distributed feedback fiber laser (3) are fixed on the cantilever beam of the GIS cover plate (1) by gluing with colloid.

3. A GIS status monitoring system based on optical fiber sensing technology according to claim 2, characterized in that: The colloid is epoxy resin.

4. The GIS status monitoring system based on optical fiber sensing technology according to claim 1 is characterized in that: The fiber Bragg grating (2) and the distributed feedback fiber laser (3) are connected to the fiber Bragg grating demodulator (4) via optical fibers.

5. The GIS status monitoring system based on optical fiber sensing technology according to claim 4 is characterized in that: The optical fiber passes through the flange on the GIS cover plate (1).

6. A GIS status monitoring method based on optical fiber sensing technology based on the GIS status monitoring system based on optical fiber sensing technology as claimed in claim 1, characterized in that: The following steps are involved: S1, fixing the fiber Bragg grating (2) and the distributed feedback fiber laser (3) on the cantilever beam of the GIS cover plate (1); S2, converting the temperature change of the GIS cover plate (1) into a first optical signal in real time through a fiber Bragg grating (2), and converting the vibration change of the GIS cover plate (1) into a second optical signal in real time through a distributed feedback fiber laser (3); S3, receiving the first optical signal and the second optical signal and performing demodulation calculation to obtain a real-time temperature change value and a partial discharge vibration signal; S4. Compare the real-time temperature change value with a preset first threshold value. If it exceeds the first threshold value, a first alarm signal is issued; analyze and process the real-time partial discharge vibration signal to determine whether there is a partial discharge phenomenon. If so, a second alarm signal is issued.

7. The GIS status monitoring method based on optical fiber sensing technology according to claim 6 is characterized in that: In step S1, the fiber Bragg grating (2) and the distributed feedback fiber laser (3) are fixed on the cantilever beam of the GIS cover plate (1) by gluing with colloid.

8. The GIS status monitoring method based on optical fiber sensing technology according to claim 6 is characterized in that: In step S4, the specific process of analyzing and processing the real-time partial discharge vibration signal is as follows: S401, after preprocessing the real-time partial discharge vibration signal, extracting time domain features and frequency domain features, the time domain features include the amplitude, duration, rise time and fall time of the partial discharge vibration signal, and the frequency domain features include the frequency component, bandwidth and main frequency of the partial discharge vibration signal; S402: Using a machine learning algorithm to identify and classify the time domain features and the frequency domain features to determine whether there is a partial discharge phenomenon.

9. The GIS status monitoring method based on optical fiber sensing technology according to claim 8 is characterized in that: In step S401, the preprocessing includes a cleaning step and a noise reduction step, and the noise reduction step uses wavelet transform, Fourier transform or Kalman filter.

10. The GIS status monitoring method based on optical fiber sensing technology according to claim 8 is characterized in that: In step S402, the machine learning algorithms include support vector machines, random forests, and deep neural networks.

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