GIS fault judgment system and method

Abstract

The invention relates to the technical field of GIS safety detection, mainly discloses a GIS fault judgment method which comprises laser detection and sensing detection, and further discloses a GIS fault judgment system which comprises a laser detection module and a sensing detection module. By reasonably setting the entering position of the collimator and utilizing the time division multiplexing principle and double-optical-fiber transmission signals, online detection of micro water and SO2F2 in the GIS gas chamber is realized, wavelength modulation and harmonic detection technologies are combined, low-frequency noise interference is reduced, the gas concentration is determined according to the second harmonic amplitude, the detection sensitivity is improved, the anti-interference capability is high, and the detection accuracy is high. The system can stably operate in a complex field environment, and the accuracy, real-time performance and reliability of detection are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of GIS safety detection, and in particular to a GIS fault judgment system and method. Background Art

[0002] Sulfur hexafluoride (SF6) is an odorless, colorless, non-toxic inert gas. Due to its excellent insulation and arc extinguishing performance, it is widely used in gas-insulated switchgear (GIS) equipment. Compared with conventional power transmission equipment, GIS equipment has the advantages of small floor area, short construction period, long maintenance period, little influence from the external environment, and high operation reliability. However, insulation defects left during the manufacturing and installation processes, such as installation scratches, fixed protrusions, and metal powder residues, can cause partial discharge phenomena inside the GIS equipment, accelerating insulation deterioration and eventually leading to equipment failure. Under the action of faults such as partial discharge and spark discharge, the chemical bonds of SF6 molecules may break, generating low-fluoride sulfides such as SF2, SF3, and SF4. Nitrogen and fluoride ions react with impurities such as solid insulation media, electrode materials, air, and moisture in the gas to form different types of compounds, such as SO2F2, SOF2, and HF.

[0003] Since the internal structure of GIS equipment is compact and complex, it is difficult to repair it after a fault occurs. Therefore, it is crucial to identify the early signs of latent faults. As an important characteristic component generated by the decomposition of SF6 under the action of partial discharge, and H2O will undergo a secondary reaction with the decomposition products of SF6. Analyzing and detecting SO2F2 and H2O can provide a basis for evaluating the insulation state of GIS equipment, thereby avoiding greater economic losses caused by faults and ensuring the safety of staff. Existing technologies are mostly designed for single gases such as SO2F2 or H2O, lacking the ability to co-detect multi-component gases and being difficult to comprehensively reflect the internal insulation deterioration state of GIS. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that existing technologies are mostly designed for single gases such as SO2F2 or H2O, lacking the ability to co-detect multi-component gases and being difficult to comprehensively reflect the internal insulation deterioration state of GIS.

[0005] The above technical problem is solved by the following technical solutions:

[0006] The present invention provides a GIS fault judgment system, which includes a laser detection module, a sensing detection module, and a fault judgment module.

[0007] In a preferred embodiment of the GIS fault judgment system of the present invention: The laser detection module is connected to the collimator of the GIS gas chamber and includes a first laser and a second laser. The first laser and the second laser are used to emit optical signals, which are reflected by the reflection mirror of the GIS gas chamber for the absorption of the gas to be measured in the GIS gas chamber. It further includes a photodetector for receiving the attenuated optical signal absorbed by the gas in the GIS gas chamber and converting it into an electrical signal to generate first data. The sensing detection module is connected to the gas outlet of the GIS gas chamber and includes a gas sensor and a heated gas cell. The heated gas cell receives and heats the introduced gas. The gas sensor is arranged in the heated gas cell and is used to judge the content of the gas to be measured in the heated gas cell and generate second data. The fault judgment module is connected to one end of the heated gas cell far from the GIS gas chamber and includes an industrial control computer. The industrial control computer is used to receive and analyze the first data and the second data, and evaluate the insulation state of the GIS and judge the fault condition of the GIS in combination with the operation history data and relevant standards of the GIS.

[0008] In a preferred embodiment of the GIS fault judgment system of the present invention: The laser detection module further includes a current driving device, a signal generator, a lock-in amplifier, a data acquisition card, and a computer interrupt processing system. The current driving device generates a low-frequency sawtooth wave signal to drive the first laser and the second laser to work alternately in a time-sharing manner. The signal generator generates a high-frequency sine modulation signal, which is superimposed on the low-frequency sawtooth wave signal of the current driving device and then input into the current driving device to realize laser wavelength scanning. The lock-in amplifier receives the electrical signal output by the photodetector, uses the high-frequency sine modulation signal of the signal generator as a reference signal, suppresses noise and extracts the second harmonic amplitude of the signal output by the photodetector. The data acquisition card acquires the signal processed by the lock-in amplifier. The computer interrupt processing system inversely calculates the concentration of the gas to be measured based on the Lambert-Beer law.

[0009] In a preferred embodiment of the GIS fault judgment system of the present invention: The sensing detection module further includes a flow meter, an industrial control computer, and a gas recovery component. The flow meter is connected to the gas outlet and the heated gas cell, and is used to quantify the gas flow rate passing through the gas outlet and transmit the data to the industrial control computer. The industrial control computer is connected to and receives the data of the gas sensor and the flow meter. The gas sensor includes an HF gas sensor, a CO gas sensor, an H2S gas sensor, and an SO2 gas sensor, which are respectively used to analyze the contents of HF, CO, H2S, and SO2. The gas recovery component recovers the gas passing through the heated gas cell.

[0010] The present invention also proposes a GIS fault judgment method, which includes laser detection, sensing detection, and fault judgment.

[0011] In a preferred embodiment of the GIS fault judgment method of the present invention: Laser detection, based on the time-division multiplexing principle, generates a superimposed signal of a low-frequency sawtooth wave and a high-frequency sine modulation signal through a current driving device, makes the first laser and the second laser emit laser alternately, and forms a folded light path in the GIS gas chamber through a reflecting mirror to extend the optical path, and detects the content of the gas to be measured in the GIS gas chamber; Sensing detection, introduces the gas in the GIS gas chamber into the heated gas cell through the air outlet, uses a gas sensor to supplement the detection of the content of the gas to be measured in the gas cell, and generates a diffusion rate-time curve in combination with the flowmeter data; Fault judgment, combines the data of laser detection and sensing detection, as well as the operation history data and relevant standards of the GIS device, evaluates the insulation state of the device, and judges the partial discharge level and insulation deterioration trend of the GIS device.

[0012] In a preferred embodiment of the GIS fault judgment method of the present invention: The laser detection is based on the time-division multiplexing principle, and the current driving device controls the first laser and the second laser to work alternately to realize the isolation of different gas detection signals.

[0013] In a preferred embodiment of the GIS fault judgment method of the present invention: The current driving device generates a low-frequency sawtooth wave signal and a high-frequency sine modulation signal, and drives the first laser and the second laser to realize wavelength scanning.

[0014] In a preferred embodiment of the GIS fault judgment method of the present invention: The first laser is a gas laser for detecting SO2F2 gas, and its central wavelength matches the absorption peak of SO2F2; the second laser is a micro-water laser for detecting H2O gas, and its central wavelength covers the absorption peak of H2O.

[0015] In a preferred embodiment of the GIS fault judgment method of the present invention: In the laser detection, the laser is converted into a parallel beam through a collimator and then enters the GIS gas chamber, and a folded light path is formed through a reflecting mirror to extend the optical path.

[0016] In a preferred embodiment of the GIS fault judgment method of the present invention: In the laser detection, the photodetector converts the optical signal into an electrical signal; the lock-in amplifier uses the high-frequency sine modulation signal as a reference signal to suppress noise and extract the second harmonic amplitude; the data acquisition card transmits the signal to the computer, and inversely calculates the gas concentration based on the Lambert-Beer law.

[0017] In a preferred embodiment of the GIS fault judgment method of the present invention: in the sensing detection, the gas sensors in the heated gas cell are an HF gas sensor, a CO gas sensor, an H2S gas sensor, and an SO2 gas sensor. The detection data is analyzed by an industrial control computer, and the detected gas is recovered and processed by a gas recovery device.

[0018] The beneficial effects of the present invention are as follows: The entry position of the collimator is reasonably set, and the time-division multiplexing principle and dual-fiber transmission signal are used to realize the on-line detection of micro water and SO2F2 in the GIS gas chamber. Combining wavelength modulation and harmonic detection technology, the low-frequency noise interference is reduced, the gas concentration is determined according to the amplitude of the second harmonic, the detection sensitivity is improved, and the anti-interference ability is strong. It can operate stably in a complex field environment, ensuring the accuracy, real-time and reliability of the detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention and do not limit the present invention.

[0020] Figure 1 Shows the flowchart of the GIS fault judgment method

[0021] Figure 2 Shows the schematic diagram of the GIS fault judgment system

[0022] Figure 3 Shows Figure 2 The enlarged view of part A of DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below in conjunction with the specific embodiments and the drawings.

[0024] The terms used in the present invention are those general terms that are currently widely used in the art in consideration of the functions of the present invention, but these terms can be changed according to the intentions of those of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms can be selected by the applicant, and in this case, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but based on the meanings of the terms and the overall description of the present invention.

[0025] Referring to Figure 1 , this embodiment provides a GIS fault judgment method, including laser detection and sensing detection.

[0026] Laser detection adopts time-division multiplexing control. The STM32 single-chip microcomputer in the current driving device generates a low-frequency sawtooth wave signal with a modulation frequency of 10 Hz, and also generates a high-frequency sine modulation signal with a modulation frequency of 10 kHz to drive the first laser and the second laser to work alternately. The lasers are switched every certain period, such as 30 seconds, to avoid signal crosstalk;

[0027] The central wavelength of the laser emitted by the first laser is 4263 cm -1 , and the wavelength range of the laser emitted by the second laser is 7140 - 7250 cm -1 . It is converted into a parallel beam through a collimator, and forms a folded-back optical path through one or more reflecting lenses in the GIS gas chamber to extend the optical path and enhance the gas absorption effect. After the laser passes through the gas absorption, the light intensity will attenuate, and the attenuation degree reflects the gas concentration information. The laser propagates in the GIS gas chamber and meets the gas to be measured in the GIS gas chamber, namely SO2F2 and trace water. According to the Lambert-Beer law, the gas absorbs the laser of a specific wavelength, and the absorption degree is related to the gas concentration.

[0028] The attenuated optical signal after gas absorption is converted into an electrical signal by a photodetector. The signal amplitude is negatively correlated with the concentrations of SO2F2 and trace water. The lock-in amplifier uses the high-frequency sine modulation signal, that is, 10 kHz, as the reference signal to extract the second harmonic amplitude in the electrical signal, suppress the environmental electromagnetic noise and low-frequency interference. The data acquisition card inputs the second harmonic amplitude and the DC component of the light intensity into the computer. Based on the Lambert-Beer law formula, the volume fraction of the gas to be measured can be calculated. When measuring SO2F2-SF6 gas with different concentrations, according to the collected second harmonic amplitude, the corresponding gas concentration can be calculated using this formula.

[0029] Considering the cross-interference of other gases in actual detection, the data processing device will process the interference signals. When studying SO2F2 gas, for interference gases such as H2S and SO2 that may exist, using the interference gas absorption characteristic data obtained from spectral simulation and experimental tests, an interference signal model is established, and through this model, the contribution of the interference gas to the signal is subtracted from the collected mixed signal, so as to obtain a more accurate SO2F2 gas signal. Analyze the processed signal and calculate parameters such as the change trend and fluctuation range of the gas concentration. Combine the operation history data of the GIS device and relevant standards to evaluate the insulation state of the device. Finally, the analysis results are presented to the user in an intuitive way, generate a curve of gas concentration changing with time, and display the current gas concentration value in real time, providing a basis for equipment maintenance and fault diagnosis.

[0030] The time-division multiplexing principle is adopted to achieve on-line detection of micro-water and SO2F2 in the GIS gas chamber. Through the control circuit, the gas laser and the micro-water laser alternately emit laser light. At a certain moment, only one laser emits laser light to detect the corresponding gas. After the detection is completed, the system switches to the other laser to detect another gas. During the switching process, the signal transmission between the detection host and the gas circuit part is realized through a double optical fiber, ensuring that the system can orderly collect the detection signals of different gases, avoiding mutual interference during the detection of different gases, and thus achieving efficient and accurate on-line detection of multiple gases.

[0031] On the basis of the above double-fiber laser detection, the diffusion rate of SF6 decomposition gas due to temperature is also detected by sensing for double detection.

[0032] For sensing detection, first, the gas in the GIS gas chamber is introduced into the heated gas cell at a constant flow rate through the gas outlet to accelerate the diffusion of decomposition gases including but not limited to HF, CO, H2S, and SO2; the gas sensor is used to synchronously collect the gas concentration in the heated gas cell, the flowmeter is used to record the change in gas flow rate, and the industrial control computer combines the temperature data, the flowmeter data, and the sensor data to establish a diffusion rate-time curve, analyze the gas release dynamics. When the diffusion rate suddenly increases, it indicates that the partial discharge intensifies, and the GIS state is comprehensively evaluated. The detected gas can be purified by a gas recovery device with activated carbon + molecular sieve as the adsorbent. After the residual waste gas concentration of the recovered SF6 meets the environmental protection emission standards, it is discharged.

[0033] During use, the laser detection adopts time-division multiplexing control to drive the first laser and the second laser to work alternately, avoiding signal crosstalk; the sensing detection uses the temperature to perform double detection on the diffusion rate of SF6 decomposition gas, improving the detection range and efficiency.

[0034] Refer to Figure 2 and Figure 3 , this embodiment provides a GIS fault judgment system, including a laser detection module 1 and a sensing detection module 2.

[0035] The current driving device 14 of the laser detection module 1 has an STM32 single-chip microcomputer built-in, generating a 10Hz low-frequency sawtooth wave signal to drive the first laser 11 and the second laser 12. The first laser 11 emits laser light with a central wavelength matching that of SO2F2, and the central wavelength is 4263 cm -1 , and the second laser emits laser light with a central wavelength covering the absorption peak of H2O, and the wavelength range is 7140 - 7250 cm -1. Both work alternately based on the time-division multiplexing principle. The laser signal is transmitted to the collimator 31 of the GIS chamber 3 through a double optical fiber. The collimator 31 converts the laser into a parallel beam, which forms a folded-back optical path after multiple reflections by the reflection mirror 33 in the GIS chamber 3 to extend the optical path and enhance the gas absorption sensitivity. The photodetector 13 receives the attenuated optical signal after gas absorption and converts it into an electrical signal.

[0036] The signal generator 15 generates a 10 kHz high-frequency sine modulation signal, which is superimposed on a 10 Hz low-frequency sawtooth wave signal and then input into the current driving device 14 to achieve laser wavelength scanning; the lock-in amplifier 16 uses the 10 kHz high-frequency sine signal as a reference to extract the second harmonic amplitude of the output signal of the photodetector 13 and suppress environmental noise; the data acquisition card 17 collects the signal processed by the lock-in amplifier 16, and the computer interrupt processing system 18 inversely calculates the real-time concentrations of SO2F2 and H2O based on the Lambert-Beer law.

[0037] The heated gas cell 25 of the sensing and detection module 2 is connected to the gas outlet 32 of the GIS chamber 3. After receiving the gas, it is heated to accelerate the decomposition of gas diffusion. And the sensing and detection module 2 is internally equipped with a flowmeter 28 to monitor the gas flow rate and record the diffusion dynamics. The sensing and detection module 2 is provided with a gas sensor group, including an HF gas sensor 21, a CO gas sensor 22, an H2S gas sensor 23, and an SO2 gas sensor 24, which are used to detect the concentrations of the corresponding gases. The industrial control computer 41 receives the data of the flowmeter 28 and each sensor, analyzes the correlation between the gas diffusion rate and the concentration, and determines the internal fault condition of the GIS according to the fault dynamic model. The gas recovery component 42 recovers the gas passing through the heated gas cell 25, and the purified waste gas meets the environmental protection emission standards.

[0038] The fault judgment module 4 is connected to one end of the heated gas cell 25 far from the GIS chamber 3, and includes an industrial control computer 41. The industrial control computer 41 is used to receive and analyze the first data and the second data, calculate the change trend and fluctuation range parameters of the concentration of the gas to be measured, and evaluate the insulation state of the GIS and judge the fault condition of the GIS in combination with the operation history data and relevant standards of the GIS.

[0039] The operation history data of the GIS includes the temperature, pressure, micro water content, SO2F2 concentration, partial discharge signal, etc. inside the device. These data can be obtained through the on-line monitoring system, regular detection, and maintenance records. The relevant standards of the GIS, including but not limited to DL / T603 and IEC62271-203, are used to determine the threshold values of key parameters, such as the standard value of the micro water content, ≤150 μL / L after overhaul and ≤300 μL / L during operation, as well as the concentration change trend of SO2F2, the intensity and type of partial discharge, etc.

[0040] Evaluate the insulation status of GIS and judge the GIS fault conditions, including using multi-information fusion methods, such as the improved DS evidence theory, to fuse the data from different detection means to improve the accuracy of evaluation. For example, by combining the capture of partial discharge signals by ultra-high frequency electromagnetic wave signals and the increase in the concentration of SO2F2, the location and type of insulation defects can be judged more accurately.

[0041] The DS evidence theory is a mathematical tool for dealing with uncertain and incomplete information. The improved DS evidence theory is an optimization method based on the classical D-S evidence theory, which is used to solve the limitations of the traditional theory in multi-source information fusion, such as weak evidence conflict handling ability, subjectivity of basic probability assignment (BPA), and unreasonable synthesis results in high-conflict scenarios.

[0042] During use, the system has a collaborative working process. The laser detection has high sensitivity, synchronously detects SO2F2 and H2O, and is linked with the sensing detection to increase the detection quantity of SF6 decomposition products. Combining with the diffusion rate model, the fault and the fault level are judged. This system can be adapted to GIS equipment of different voltage levels, and its performance can be optimized by adjusting the optical path length and heating temperature.

[0043] Finally, it should be pointed out that the methods and devices described in detail above are only examples, and those skilled in the art can modify these examples in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A GIS fault judgment system, characterized in that: including, a laser detection module (1), a collimator (31) connected to a GIS chamber (3), including a first laser (11) and a second laser (12), the first laser (11) and the second laser (12) being used to emit optical signals, which are reflected by a reflecting lens (33) of the GIS chamber (3) for absorption by the gas to be measured in the GIS chamber (3); further including a photodetector (13) for receiving the attenuated optical signal absorbed by the gas in the GIS chamber (3) and converting it into an electrical signal to generate first data; a sensing detection module (2), connected to an air outlet (32) of the GIS chamber (3), including a gas sensor (B) and a heated gas cell (25); the heated gas cell (25) receives and heats the introduced gas, and the gas sensor (B) is arranged in the heated gas cell (25) and is used to judge the content of the gas to be measured in the heated gas cell (25) and generate second data; and, a fault judgment module (4), connected to one end of the heated gas cell (25) away from the GIS chamber (3), including an industrial control computer (41), the industrial control computer (41) being used to receive and analyze the first data and the second data, calculate the change trend and fluctuation range parameters of the concentration of the gas to be measured, and evaluate the insulation state of the GIS and judge the GIS fault situation in combination with the operation history data and relevant standards of the GIS.

2. The GIS fault judgment system according to claim 1, characterized in that: the laser detection module (1) further includes a current driving device (14), a signal generator (15), a lock-in amplifier (16), a data acquisition card (17) and a computer interrupt processing system (18); the current driving device (14) generates a low-frequency sawtooth wave signal to drive the first laser (11) and the second laser (12) to work alternately in a time-sharing manner; the signal generator (15) generates a high-frequency sine modulation signal, which is superimposed on the low-frequency sawtooth wave signal of the current driving device (14) and then input into the current driving device (14) to realize laser wavelength scanning; the lock-in amplifier (16) receives the electrical signal output by the photodetector (13), uses the high-frequency sine modulation signal of the signal generator (15) as a reference signal, suppresses noise and extracts the second harmonic amplitude of the signal output by the photodetector (13); the data acquisition card (17) acquires the signal processed by the lock-in amplifier (16); the computer interrupt processing system (18) inversely calculates the concentration of the gas to be measured based on the Lambert-Beer law.

3. The GIS fault judgment system according to claim 2, characterized in that: the sensing detection module (2) further includes a flowmeter (28), an industrial control computer (41) and a gas recovery component (42); the flowmeter (28) is connected to the air outlet (32) and the heated gas cell (25), and is used to quantify the gas flow rate passing through the air outlet (32) and transmit the data to the industrial control computer (41); The industrial control computer (41) is connected to and receives data from the gas sensor (B) and the flowmeter (28). The gas sensor (B) includes an HF gas sensor (21), a CO gas sensor (22), an H2S gas sensor (23), and an SO2 gas sensor (24), which are respectively used to analyze the contents of HF, CO, H2S, and SO2. The gas recovery assembly (42) recovers the gas passing through the heated gas cell (25).

4. A GIS fault judgment method, characterized in that: including, Laser detection is based on the time-division multiplexing principle. A superimposed signal of a low-frequency sawtooth wave and a high-frequency sine modulation signal is generated by a current driving device, enabling the first laser and the second laser to alternately emit laser light. A folded optical path is formed through a reflecting mirror in the GIS gas chamber to extend the optical path, and the content of the gas to be measured in the GIS gas chamber is detected. Sensing detection: The gas in the GIS gas chamber is introduced into the heated gas cell through the gas outlet. A gas sensor is used to supplement the detection of the content of the gas to be measured in the gas cell, and a diffusion rate-time curve is generated in combination with the flowmeter data. Fault judgment: Combining the data of laser detection and sensing detection, as well as the operation history data and relevant standards of the GIS device, the insulation state of the device is evaluated, and the partial discharge level and insulation deterioration trend of the GIS device are judged.

5. The GIS fault judgment method according to claim 4, wherein: The laser detection is based on the time-division multiplexing principle, and the current driving device controls the first laser and the second laser to alternately operate to achieve isolation of different gas detection signals.

6. The GIS fault judgment method according to claim 5, wherein: The current driving device generates a low-frequency sawtooth wave signal and a high-frequency sine modulation signal to drive the first laser and the second laser to achieve wavelength scanning.

7. The GIS fault judgment method according to claim 6, wherein: The first laser is a gas laser for detecting SO2F2 gas, and its central wavelength matches the absorption peak of SO2F2. The second laser is a micro-water laser for detecting H2O gas, and its central wavelength covers the absorption peak of H2O.

8. The GIS fault judgment method according to claim 7, wherein: In the laser detection, the laser is converted into a parallel beam through a collimator and then enters the GIS gas chamber. A folded optical path is formed through a reflecting mirror to extend the optical path.

9. The GIS fault judgment method according to claim 8, wherein: In the laser detection, the photodetector converts the optical signal into an electrical signal; The lock-in amplifier uses the high-frequency sine modulation signal as a reference signal to suppress noise and extract the second harmonic amplitude; The data acquisition card transmits the signal to the computer, and the gas concentration is inversely calculated based on the Lambert-Beer law.

10. The GIS fault judgment method according to claim 9, wherein: In the sensing detection, the gas sensors in the heated gas cell are set as an HF gas sensor, a CO gas sensor, an H2S gas sensor, and an SO2 gas sensor. The detection data is analyzed by the industrial control computer, and the detected gas is recovered and processed by a gas recovery device.

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