Variable-optical-path gas multi-component detection method and variable-optical-path gas multi-component detection system

Abstract

The invention discloses a variable-optical-path gas multi-component detection method and system, relates to the technical field of power distribution detection, and realizes self-adaptive detection of high-concentration and low-concentration scenes by dynamically adjusting an optical path by utilizing linkage of a threshold sensor and a reflector group through the processes of laser detection, concentration judgment and optical path adjustment. The detection sensitivity and the measuring range are improved; the laser is rapidly switched in combination with the mounting piece, the characteristic absorption peaks of various SF6 decomposition components are synchronously matched, the multi-component detection time is shortened, the cross interference error is reduced, the real-time requirement of GIS equipment live detection is met, and the fault early warning efficiency and the operation safety of a power system are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution detection, and in particular to a method and system for detecting multiple gas components with variable optical path. Background Art

[0002] SF6 gas is often used as an insulating medium for power equipment. However, when partial discharge or overheating occurs inside the equipment, it will decompose to produce sulfuryl fluoride SO2F2, sulfurous oxyfluoride SOF=, hydrogen fluoride HF, etc. The concentrations of these products are directly related to the severity of insulation defects in the equipment.

[0003] In the existing detection technologies, although the infrared spectroscopy method can identify gases based on the molecular absorption characteristics, the detection effect is not good due to the static optical path design. With a fixed optical path length, when detecting low-concentration gases, the absorption path is relatively short, resulting in weak laser absorption and a high detection limit; while in the face of high-concentration gases, the relatively long absorption path will cause light intensity saturation, making it impossible to accurately quantify the concentration change and resulting in a low detection upper limit. This makes the static optical path design extremely poor in adaptability under complex working conditions and prone to missed detection or misjudgment.

[0004] In addition, when using the concentrations of SO2F2, SOF2, and HF and their ratios for fault diagnosis of GIS equipment, the diagnosis level of GIS insulation defects can be greatly improved, and latent faults can be warned in a timely manner. However, due to insufficient resolution of traditional broadband infrared light sources, it is difficult to distinguish the overlapping absorption peaks of gases such as SO2F2, SOF2, and HF, further exacerbating the problem of cross-interference. Existing laser solutions are limited by single-wavelength detection and static optical path adjustment capabilities, and cannot achieve synchronous detection of multiple components and dynamic concentration adaptation, resulting in low efficiency of on-site live detection and high operation and maintenance costs.

[0005] Therefore, there is an urgent need for a detection system with both the ability to identify multiple components and dynamic optical path adaptive adjustment to improve the status monitoring level of power equipment. Summary of the Invention

[0006] Therefore, the technical problems to be solved by the present invention are as follows: The detection accuracy of gas components with a fixed optical path is low, and the lack of a rapid laser switching mechanism results in low efficiency of multi-component detection.

[0007] The above technical problems are solved by the following technical solutions:

[0008] The present invention provides a method for detecting multiple gas components with variable optical path, which includes concentration judgment, optical path adjustment, and laser detection.

[0009] In a preferred embodiment of the gas multi-component detection method with variable optical path according to the present invention: Concentration judgment, the gas to be measured passing through the gas cell is introduced into the trachea, and the threshold sensor at one end of the trachea is used to detect the gas concentration range in real time; Optical path adjustment, if the gas concentration range is higher than the preset threshold range, it is judged as high concentration, the threshold sensor emits a first signal, and the telescopic member is controlled to move the movable mirror linked to the telescopic member closer to the fixed mirror to reduce the optical path. If the gas concentration range is lower than the preset threshold range, it is judged as low concentration, the threshold sensor emits a second signal, and the telescopic member is controlled to move the movable mirror away from the fixed mirror to increase the optical path; Laser detection, the gas to be measured is passed through the gas cell, and a laser is used to emit laser light. When the laser light is reflected between the fixed mirror and the movable mirror in the gas cell, it is absorbed by the gas to be measured.

[0010] In a preferred embodiment of the gas multi-component detection method with variable optical path according to the present invention: The laser detection further includes that after the laser light exits the gas cell, it enters the signal conversion member and is converted into an electrical signal by the signal conversion member, stored in the signal processing member, and according to the Beer-Lambert law, the specific gas concentration value is calculated based on the optical path length and the light intensity attenuation value.

[0011] In a preferred embodiment of the gas multi-component detection method with variable optical path according to the present invention: The laser detection further includes that before the laser light enters the gas cell, by adjusting the mounting member, the laser used to emit laser light into the gas cell is changed to detect the concentrations of different gases.

[0012] The present invention also provides a gas multi-component detection system with variable optical path, which includes a laser detection module, an optical path adjustment module, and a gas cell.

[0013] In a preferred embodiment of the gas multi-component detection system with variable optical path according to the present invention: The gas cell is provided with an air inlet and an air outlet for the gas in the GIS device to flow through, and also includes a light inlet and a light outlet for the laser light to enter and exit; The laser detection module is arranged at one end of the gas cell and includes a plurality of lasers mounted on the mounting member; It also includes a first condenser lens facing the light inlet, and the lasers face the first condenser lens during use; And the optical path adjustment module is arranged inside the gas cell and includes a fixed mirror and a movable mirror. The laser light emitted by the lasers passes through the first condenser lens and the light inlet and irradiates into the gas cell, and is reflected by the fixed mirror and the movable mirror.

[0014] In a preferred embodiment of the gas multi-component detection system with variable optical path according to the present invention: The laser detection module further includes a second condenser lens facing the light outlet, and the laser light reflected by the fixed mirror and the movable mirror exits from the light outlet and irradiates the second condenser lens.

[0015] In a preferred embodiment of the variable optical path gas multi-component detection system of the present invention: the laser detection module also includes a signal conversion component and a signal processing component, the signal conversion component is directly opposite to the second condenser, and converts the laser passing through the second condenser from an optical signal to an electrical signal, and transmits it to the signal processing component, the signal processing component processes the electrical signal to invert the concentration of the gas to be measured.

[0016] In a preferred embodiment of the variable optical path gas multi-component detection system of the present invention: the optical path adjustment module also includes an air pipe and a threshold sensor, the air pipe is arranged outside the gas pool, one end is connected to the gas outlet, and the other end is connected to the threshold sensor; the threshold sensor is used to determine the concentration range of the gas to be measured in the gas passing through the inside of the gas pool.

[0017] In a preferred embodiment of the variable optical path gas multi-component detection system of the present invention: the optical path adjustment module also includes a telescopic member, the fixed end of the telescopic member is electrically connected to the threshold sensor, and the movable end of the telescopic member is connected to the bottom of the movable reflector through the gas pool wall.

[0018] In a preferred embodiment of the variable optical path gas multi-component detection system of the present invention: the fixed reflector is installed on one side of the inside of the gas pool, the fixed reflector has multiple pieces, the movable reflector is installed on the side of the inside of the gas pool opposite to the fixed reflector, the number of movable reflector lenses matches the number of fixed reflector lenses, and the laser emitted by the laser is reflected by the movable reflector and the fixed reflector, and then emitted from the gas pool from the light outlet.

[0019] In a preferred embodiment of the gas multi-component detection system with variable optical path length of the present invention: the telescopic direction of the telescopic member is parallel to the laser direction emitted by the laser.

[0020] The beneficial effects of the present invention are as follows: the optical path is dynamically adjusted by linking the threshold sensor with the reflector group to achieve adaptive detection of high-concentration and low-concentration scenes, thereby improving the detection sensitivity and measuring range; and the laser is quickly switched in combination with the mounting parts to synchronously match the characteristic absorption peaks of various SF6 decomposition components, thereby reducing the multi-component detection time and cross-interference errors, meeting the real-time requirements of live detection of GIS equipment, and significantly improving the fault warning efficiency and operational safety of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0022] Figure 1 The flowchart of the gas multi-component detection method with variable optical path is shown;

[0023] Figure 2 The schematic diagram of the gas multi-component detection system with variable optical path is shown;

[0024] Figure 3 The short optical path schematic diagram of the gas multi-component detection system with variable optical path is shown;

[0025] Figure 4 The long optical path schematic diagram of the gas multi-component detection system with variable optical path is shown. Specific embodiments

[0026] 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 specific embodiments and the accompanying drawings.

[0027] 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 may vary according to the intentions of those of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms may 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.

[0028] Referring to Figure 1 , this embodiment provides a gas multi-component detection method with variable optical path, including concentration judgment, optical path adjustment, and laser detection.

[0029] First, the gas to be measured passes through the gas cell, and the threshold sensor at one end of the trachea detects the gas concentration range in real time. The gas cell is a closed cavity structure, provided with an air inlet and an air outlet to carry the gas to be measured and allow the gas to be measured to enter and exit, and also provided with a light inlet and a light outlet for the laser to enter and exit; the trachea connects the air outlet and the threshold sensor, and is used to pass the gas to be measured so that the threshold sensor can judge the content range of the component to be measured in the overall gas to be measured, thereby facilitating the selection of the most appropriate optical path.

[0030] There are multiple components to be measured, including but not limited to SO2F2, SOF2, and HF, and each laser corresponds to one component to be measured.

[0031] After the threshold sensor judges the content range of the component to be measured in the overall gas to be measured, by comparing the threshold range, it issues a command to control the telescopic member to increase or decrease the optical path. When the concentration of the component to be measured is high, it issues a first command to make the fixed mirror and the movable mirror approach; when the concentration of the component to be measured is low, it issues a second command to make the fixed mirror and the movable mirror approach.

[0032] Then select the corresponding laser to emit laser light. When the laser light is reflected between the fixed mirror and the movable mirror inside the gas cell, it is absorbed by the gas to be measured. The laser light is converted into an electrical signal by the signal conversion component, and the signal processing component calculates the specific concentration value of the gas according to the Beer-Lambert law based on the optical path length and the light intensity attenuation value, so as to obtain the accurate concentration of the gas to be measured.

[0033] In another embodiment, the threshold sensor can be removed, and the signal processing component is directly connected to the telescopic component. First, directly use the laser to measure the concentration of the gas, then adjust the optical path according to the measured concentration, and then use the laser to measure the concentration of the gas again to improve the detection accuracy. Among them, adjusting the optical path according to the measured concentration is also to issue a first command to make the fixed mirror and the movable mirror approach when the concentration of the component to be measured is high; when the concentration of the component to be measured is low, issue a second command to make the fixed mirror and the movable mirror approach, so that subsequent detection is within a more appropriate optical path range, improving the detection accuracy.

[0034] Refer to Figure 2 , this embodiment provides a variable optical path gas multi-component detection system, including a laser detection module 1, an optical path adjustment module 2 and a gas cell 3, which is used to detect the decomposition components of SF6.

[0035] The gas cell 3 is provided with an air inlet 31 and an air outlet 32 for the gas in the GIS device to flow through, and also includes an incident light port 33 and an outgoing light port 34 for the laser to enter and exit. The gas cell 3 is a corrosion-resistant sealed cavity. The air inlet 31 is connected to the GIS device, and the air outlet 32 is connected to the trachea 23. The incident light port 33 and the outgoing light port 34 respectively correspond to the first condenser lens 13 and the second condenser lens 14 to ensure the focused light path when the laser penetrates the gas cell.

[0036] The laser detection module 1 is arranged at one end of the gas cell 3 and includes a plurality of lasers 11 mounted on the mounting member 12; it also includes a first condenser lens 13, which is directly opposite to the incident light port 33, and the lasers 11 are directly opposite to the first condenser lens 13 during use. The plurality of lasers 11 include but are not limited to SO2F2 lasers, SOF2 lasers and HF lasers, and each laser corresponds to a component to be measured. The mounting member 12 is used to mount and switch the lasers 11. The laser 11 in use is directly opposite to the first condenser lens 13, and the emitted laser light is focused by the first condenser lens 13, improving the parallelism and preventing the excessive diffusion of the laser light when the optical path is extended, resulting in the light intensity attenuation exceeding the detection range.

[0037] The optical path adjustment module 2 is arranged inside the gas pool 3, and includes a fixed reflector 21 and a movable reflector 22. The laser emitted by the laser 11 is irradiated into the gas pool 3 through the first condenser 13 and the light inlet 33, and is reflected by the fixed reflector 21 and the movable reflector 22. The laser exits the gas pool 3 after being reflected by the fixed reflector 21 and the movable reflector 22, which lengthens the optical path. When the fixed reflector 21 and the movable reflector 22 are close to each other, the optical path will be shortened, so as to adjust the optical path to adapt to different concentrations of the components to be measured and improve the detection effect.

[0038] The laser detection module 1 also includes a second condenser 14, which is directly opposite to the light outlet 34. The laser reflected by the fixed reflector 21 and the movable reflector 22 is emitted from the light outlet 34 and illuminates the second condenser 14. The second condenser 14 is used to focus the laser to the signal conversion element 15 to ensure efficient conversion of the optical signal.

[0039] The laser detection module 1 also includes a signal conversion component 15 and a signal processing component 16. The signal conversion component 15 is directly opposite to the second condenser 14, and converts the laser passing through the second condenser 14 from an optical signal into an electrical signal, and transmits it to the signal processing component 16. The signal processing component 16 processes the electrical signal and inverts the concentration of the gas to be measured according to the Beer-Lambert law.

[0040] The optical path adjustment module 2 also includes an air pipe 23 and a threshold sensor 24. The air pipe 23 is arranged outside the gas pool 3, one end of which is connected to the gas outlet 32, and the other end is connected to the threshold sensor 24; the threshold sensor 24 is used to determine the concentration range of the gas to be tested in the gas passing through the gas pool 3. The air pipe 23 is used to transport the gas to be tested, and the threshold sensor 24 detects the gas concentration range to trigger the optical path adjustment instruction.

[0041] The optical path adjustment module 2 also includes a telescopic member 25, a fixed end of the telescopic member 25 is electrically connected to the threshold sensor 24, and a movable end of the telescopic member 25 is connected to the bottom of the movable reflector 22 through the wall of the gas pool 3. After the threshold sensor 24 detects the gas concentration range, it compares it with the preset threshold range. If the gas concentration range is higher than the preset threshold range, it is judged to be a high concentration. The threshold sensor sends a first signal to control the telescopic member to make the movable reflector linked to the telescopic member close to the fixed reflector to reduce the optical path. If the gas concentration range is lower than the preset threshold range, it is judged to be a low concentration. The threshold sensor sends a second signal to control the telescopic member to make the movable reflector away from the fixed reflector to increase the optical path.

[0042] The telescopic member 25 is composed of a transmission shaft motor and a base, and the transmission shaft motor adjusts the position of the base by telescoping. The movable reflector 22 and the base are connected across the wall of the gas pool 3, and the magnetic coupling transmission technology is adopted to ensure that the gas pool 3 is sealed, and the movement of the base can drive the movement of the movable reflector 22 in the gas pool 3.

[0043] The fixed mirror 21 is installed on one side inside the gas cell 3, and there are multiple pieces of the fixed mirror 21. The movable mirror 22 is installed on the side opposite to the fixed mirror 21 inside the gas cell 3, and the number of lenses of the movable mirror 22 matches the number of lenses of the fixed mirror 21. The laser emitted by the laser 11 is reflected by the movable mirror 22 and the fixed mirror 21 and then exits the gas cell 3 from the light outlet 34. The angle between the mirror and the laser is 45 degrees, ensuring that the laser optical path is always perpendicular or parallel to the telescopic direction of the telescopic member 25. At the same time, in most cases, the laser optical path is parallel to the telescopic direction of the telescopic member 25.

[0044] Finally, it should be noted 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 method for detecting multiple components of gas with variable optical path, characterized in that: Including, Concentration judgment: The gas to be measured passing through the gas cell is introduced into the trachea, and the threshold sensor at one end of the trachea is used to detect the gas concentration range in real time. Optical path adjustment: If the gas concentration range is higher than the preset threshold range, it is judged as high concentration. The threshold sensor emits a first signal to control the telescopic member to make the movable mirror linked to the telescopic member approach the fixed mirror, reducing the optical path. If the gas concentration range is lower than the preset threshold range, it is judged as low concentration. The threshold sensor emits a second signal to control the telescopic member to make the movable mirror move away from the fixed mirror, increasing the optical path. Laser detection: Let the gas to be measured pass through the gas cell, and use a laser to emit laser light. The laser light is absorbed by the gas to be measured when it is reflected between the fixed mirror and the movable mirror in the gas cell.

2. The variable optical path gas multi-component detection method according to claim 1, characterized in that: The laser detection further includes that after the laser light exits the gas cell, it enters the signal conversion member and is converted into an electrical signal by the signal conversion member, stored in the signal processing member, and according to the Beer-Lambert law, the specific gas concentration value is calculated based on the optical path length and the light intensity attenuation value.

3. The variable optical path gas multi-component detection method according to claim 2, characterized in that: The laser detection further includes that before the laser light enters the gas cell, by adjusting the mounting member, the laser that emits laser light into the gas cell is changed to detect the concentrations of different gases.

4. A gas multi-component detection system with variable optical path, characterized in that: Including, Gas cell (3), provided with an air inlet (31) and an air outlet (32) for the gas in the GIS equipment to flow through, and also including a light inlet (33) and a light outlet (34) for the laser light to enter and exit. Laser detection module (1), arranged at one end of the gas cell (3), including a plurality of lasers (11) mounted on the mounting member (12); also including a first condenser lens (13) facing the light inlet (33) directly, and the lasers (11) face the first condenser lens (13) during use; and, Optical path adjustment module (2), arranged inside the gas cell (3), including a fixed mirror (21) and a movable mirror (22), and the laser light emitted by the lasers (11) passes through the first condenser lens (13) and the light inlet (33) and irradiates into the gas cell (3), and is reflected by the fixed mirror (21) and the movable mirror (22).

5. The variable optical path gas multi-component detection system according to claim 4, characterized in that: The laser detection module (1) further includes a second condenser lens (14) facing the light outlet (34) directly, and the laser light reflected by the fixed mirror (21) and the movable mirror (22) exits from the light outlet (34) and irradiates the second condenser lens (14).

6. The variable optical path gas multi-component detection system according to claim 5, characterized in that: The laser detection module (1) further comprises a signal conversion component (15) and a signal processing component (16); the signal conversion component (15) is directly opposite to the second condenser (14) and converts the laser light passing through the second condenser (14) from an optical signal into an electrical signal and transmits the optical signal to the signal processing component (16); the signal processing component (16) processes the electrical signal and inverts the concentration of the gas to be measured.

7. The gas multi-component detection system with variable optical path length according to claim 6, characterized in that: The optical path adjustment module (2) further comprises an air pipe (23) and a threshold sensor (24); the air pipe (23) is arranged outside the gas pool (3), one end of the air pipe is connected to the gas outlet (32), and the other end is connected to the threshold sensor (24); the threshold sensor (24) is used to determine the concentration range of the gas to be measured in the gas passing through the inside of the gas pool (3).

8. The gas multi-component detection system with variable optical path length according to claim 7, characterized in that: The optical path adjustment module (2) further comprises a telescopic member (25), wherein a fixed end of the telescopic member (25) is electrically connected to the threshold sensor (24), and a movable end of the telescopic member (25) is connected to the bottom of the movable reflector (22) via a wall of the gas pool (3).

9. The gas multi-component detection system with variable optical path length according to claim 8, characterized in that: The fixed reflector (21) is installed on one side inside the gas pool (3), and the fixed reflector (21) has a plurality of pieces. The movable reflector (22) is installed on the side inside the gas pool (3) opposite to the fixed reflector (21), and the number of lenses of the movable reflector (22) matches the number of lenses of the fixed reflector (21). The laser light emitted by the laser (11) is reflected by the movable reflector (22) and the fixed reflector (21) and then emitted from the gas pool (3) from the light outlet (34).

10. The gas multi-component detection system with variable optical path length according to claim 9, characterized in that: The telescopic direction of the telescopic member (25) is parallel to the direction of the laser light emitted by the laser (11).

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