Multi-gas simultaneous detection device based on optical fiber annular cavity

Abstract

The invention relates to the technical field of gas detection, in particular to a multi-gas simultaneous detection device based on an optical fiber annular cavity. The laser is connected with the signal generator; at least two reaction units; the optical switch is connected with the laser and the input end of the reaction unit; the beam combiner is connected with the output ends of all the reaction units; the detection unit is connected with the beam combiner; the trace detection of SF6 decomposed components (SO2 and H2S) is realized through an optical fiber sensing technology and an optical fiber ring cavity ring-down spectroscopy technology, laser pulses are injected into an annular resonant cavity formed by a high-precision optical fiber coupler, and when the laser pulses are influenced by the concentration of external gas, optical signals transmitted in optical fibers can change, so that the trace detection of the SF6 decomposed components (SO2 and H2S) is realized. And the gas concentration is detected by utilizing the intensity attenuation characteristic of the light pulse when the light pulse is circularly propagated in the cavity, so that whether the SF6 gas is decomposed or not is accurately determined, and timely operation is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, in particular to a multi-gas simultaneous detection device based on an optical fiber ring cavity. Background Art

[0002] Sulfur hexafluoride (SF6) has become an indispensable key insulating medium for gas-insulated switchgear (GIS) and circuit breakers due to its excellent dielectric strength and superior arc-extinguishing performance. The widespread use of this inert gas in high-voltage electrical equipment has greatly improved the reliability and compactness of power systems. However, when partial discharge or arc fault occurs inside the equipment, SF6 gas decomposes to produce a variety of characteristic gases, including sulfur dioxide (SO2) and hydrogen sulfide (H2S). The appearance of these decomposition products not only significantly reduces the original insulation performance of SF6, but may also trigger a chain chemical reaction, further aggravating equipment degradation. Therefore, establishing an effective SF6 decomposition gas monitoring system is of decisive significance to ensuring the safe operation of power equipment.

[0003] Existing gas detection methods mainly include the following: 1. Gas chromatography; after separating the gas components through a chromatographic column, a thermal conductivity detector or a flame photometer is used for quantitative analysis; 2. Infrared spectroscopy; the characteristic absorption of different gas molecules in a specific infrared band is used for detection; 3. Electrochemical sensor method; the redox reaction of the gas on the electrode surface generates an electrical signal; 4. Photoacoustic spectroscopy; detection is based on the acoustic wave signal generated by the gas absorption modulated light radiation; although there are various detection methods for SF6 decomposition characteristic gases, each method has certain limitations; gas chromatography has a long analysis cycle and a large equipment size, making it difficult to achieve rapid on-site detection; infrared spectroscopy is easily interfered by moisture and dust, and is not sensitive enough to low-concentration gases; electrochemical sensors have obvious cross-sensitivity problems; photoacoustic spectroscopy equipment is expensive, sensitive to vibration, and has poor adaptability to the on-site environment, which makes the detection of SF6 gas more difficult. Therefore, a multi-gas simultaneous detection device based on an optical fiber ring cavity is proposed to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-gas simultaneous detection device based on an optical fiber ring cavity, which aims to solve the problem that the existing SF6 detection method has limitations and causes the SF6 gas detection to be not accurate enough.

[0005] The present invention proposes the following technical solution: a multi-gas simultaneous detection device based on an optical fiber ring cavity, which includes

[0006] Signal generator;

[0007] a laser connected to the signal generator;

[0008] at least two reaction units;

[0009] an optical switch, connecting the laser and the input end of the reaction unit;

[0010] A beam combiner, connecting the output ends of all reaction units;

[0011] a detection unit connected to the beam combiner;

[0012] The optical signal emitted by the laser can be diverted to the input ends of all reaction units through the optical switch, and the optical signal output from the output end of the reaction unit is processed by the beam combiner and then transmitted to the detection unit for detection.

[0013] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: the reaction unit includes a SO2 reaction unit and an H2S reaction unit, the SO2 reaction unit includes a coupler 1, and the H2S reaction unit includes a coupler 3.

[0014] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: one end of the coupler 1 is connected to the optical isolator 1, and one end of the coupler 3 is connected to the optical isolator 2.

[0015] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: one end of the optical isolator 1 is connected to the gas chamber 1, and one end of the optical isolator 2 is connected to the gas chamber 2.

[0016] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: an SO2 sensor is provided inside the gas chamber one, and an H2S sensor is provided inside the gas chamber two.

[0017] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: one end of the SO2 sensor is connected to a second coupler, and one end of the H2S sensor is connected to a fourth coupler.

[0018] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: one end of the second coupler is connected to the first optical fiber ring, and one end of the fourth coupler is connected to the second optical fiber ring.

[0019] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: the optical fiber ring 1 is connected to the coupler 1, and the optical fiber ring 2 is connected to the coupler 3.

[0020] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: the second coupler and the fourth coupler are both connected to the beam combiner.

[0021] As a preferred embodiment of the multi-gas simultaneous detection device based on the optical fiber ring cavity of the present invention: the detection unit includes a photoelectric detector and a host computer, and the photoelectric detector is connected to the beam combiner.

[0022] The beneficial effects of the present invention are as follows: through optical fiber sensing technology and optical fiber ring cavity ring-down spectroscopy technology, trace detection of SF6 decomposition components (SO2, H2S) is achieved. This technology injects laser pulses into a ring resonant cavity composed of a high-precision optical fiber coupler. When affected by the external gas concentration, the optical signal transmitted in the optical fiber will change. The intensity attenuation characteristics of the optical pulse when it circulates in the cavity are used to detect the gas concentration, thereby accurately determining whether SF6 gas has decomposed, facilitating timely operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0024] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0026] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, 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 rather as the meanings of the terms and the overall description of the present invention.

[0027] Example 1, reference Figure 1 This embodiment provides a multi-gas simultaneous detection device based on an optical fiber ring cavity, comprising:

[0028] Signal generator 1;

[0029] Laser 2, connected to signal generator 1;

[0030] at least two reaction units;

[0031] Optical switch 3, connecting the laser 2 and the input end of the reaction unit;

[0032] A beam combiner 10, connecting the output ends of all reaction units;

[0033] a detection unit connected to the beam combiner 10;

[0034] The optical signal emitted by the laser 2 can be diverted to the input ends of all reaction units through the optical switch 3, and the optical signal output from the output end of the reaction unit is processed by the beam combiner 10 and then transmitted to the detection unit for detection.

[0035] The optical switch 3 can simultaneously send pulse light signals to the coupler 1 5 and the coupler 3 14, thereby simultaneously activating the SO2 sensor 8 and the H2S sensor 15, and detecting the two gases at the same time, thereby ensuring that the gas after SF6 decomposition is detected, making it convenient for users to know whether SF6 is decomposed in time and take timely remedial measures.

[0036] Usage process: Turn on the signal generator 1, emit an electrical signal of specific frequency and amplitude, drive the laser 2, the laser 2 emits a laser, generates a pulsed light signal, the optical switch 3 sends the light signal to the two reaction units at the same time, the two reaction units transmit the light signal to the combiner 10, turn on the detection unit, the detection unit reads and saves the ring-down signal output by the combiner 10, performs fitting processing on the ring-down signal, establishes a linear relationship between the gas concentration and the ring-down signal, and thus realizes the detection of the gas.

[0037] Example 2, reference Figure 1 , which is the second embodiment of the present invention, differs from the previous embodiment in that it further includes,

[0038] One end of coupler 2 7 is connected to optical fiber ring 1 4 , and one end of coupler 4 17 is connected to optical fiber ring 2 18 .

[0039] Fiber ring 1 4 and fiber ring 2 18 are connected between coupler 2 7 and coupler 1 5, and between coupler 3 14 and coupler 4 17, respectively. The ring-down pulse signal generated by fiber ring 1 4 circulates repeatedly through coupler 1 5, optical isolator 1 6, SO2 sensor 8, coupler 2 7, and fiber ring 1 4. When the pulse light signal from optical switch 3 enters coupler 1 5, the pulse light signal inside coupler 1 5 mixes with the ring-down pulse signal generated by fiber ring 1 4. The optical signal is processed, allowing photodetector 11 and host computer 12 to analyze and obtain the required data.

[0040] Usage process: Fiber ring 1 4 and fiber ring 2 18 generate ring-down pulse signals, driving the optical signals inside coupler 1 5 and coupler 3 14 to ring down cyclically, thereby enabling the photodetector 11 and the host computer 12 to perform analysis.

[0041] Example 3, reference Figure 1 , which is the third embodiment of the present invention, is different from the previous embodiment in that it further includes:

[0042] The reaction unit includes a SO2 reaction unit and a H2S reaction unit. The SO2 reaction unit includes a coupler 1 5, and the H2S reaction unit includes a coupler 3 14.

[0043] Coupler 1 5 and coupler 14 couple the laser pulses into optical isolator 6 and optical isolator 2 13 respectively.

[0044] One end of coupler 1 5 is connected to optical isolator 1 6 , and one end of coupler 3 14 is connected to optical isolator 2 13 .

[0045] Optical isolator 1 6 and optical isolator 2 13 can protect the optical path and prevent light from being transmitted back to the laser 2.

[0046] One end of optical isolator 1 6 is connected to air chamber 1 9 , and one end of optical isolator 2 13 is connected to air chamber 2 16 .

[0047] Gas chamber 1 9 and gas chamber 2 16 are cleaned with nitrogen before detection, and then the gas to be tested is introduced into gas chamber 1 9 and gas chamber 2 16. The SO2 sensor 8 is set in gas chamber 1 9 and the H2S sensor 15 is set in gas chamber 2 16 to detect the gas.

[0048] An SO2 sensor 8 is provided inside the gas chamber 1 9 , and an H2S sensor 15 is provided inside the gas chamber 2 16 .

[0049] The SO2 sensor 8 and the H2S sensor 15 can detect SO2 gas and H2S gas, thereby obtaining data of SO2 gas and H2S gas in the gas to be tested.

[0050] One end of the SO 2 sensor 8 is connected to a coupler 2 7 , and one end of the H 2 S sensor 15 is connected to a coupler 2 17 .

[0051] Coupler 2 7 and coupler 17 can respectively connect the SO 2 sensor 8 and the beam combiner 10 and the H 2 S sensor 15 and the beam combiner 10 , so that the optical signals of the SO 2 sensor 8 and the H 2 S sensor 15 are transmitted to the beam combiner 10 .

[0052] Fiber optic ring 1 4 is connected to coupler 1 5 , and fiber optic ring 2 18 is connected to coupler 3 14 .

[0053] Coupler 1 5 can connect optical switch 3 and optical isolator 1 6 , and coupler 3 14 can connect optical switch 3 and optical isolator 2 13 , so that the optical signal of optical switch 3 can be transmitted to optical isolator 1 6 and optical isolator 2 13 .

[0054] Coupler 2 7 and coupler 4 17 are both connected to the combiner 10.

[0055] Coupler 2 7 can connect the SO 2 sensor 8 and the beam combiner 10 , and coupler 17 can connect the H 2 S sensor 15 and the beam combiner 10 , so that the optical signals of the SO 2 sensor 8 and the H 2 S sensor 15 are transmitted to the beam combiner 10 .

[0056] The detection unit includes a photodetector 11 and a host computer 12 . The photodetector 11 is connected to the beam combiner 10 .

[0057] The photoelectric detector 11 and the host computer 12 can read and store the ring-down signal output by the beam combiner 10, thereby realizing the simultaneous detection of two gases.

[0058] Usage process: nitrogen is introduced into gas chamber 1 9 and gas chamber 2 16 to clean gas chamber 1 9 and gas chamber 2 16, and then the gas to be measured is introduced into gas chamber 1 9 and gas chamber 2 16 respectively. After the airflow is stable, the signal generator 1 is turned on to emit an electrical signal of a specific frequency and amplitude to drive the laser 2. The laser 2 emits a laser to generate a pulsed light signal. The optical switch 3 simultaneously sends the light signal into coupler 1 5 and coupler 3 14. Coupler 1 5 and coupler 3 14 couple the laser pulse into optical isolator 1 6 and optical isolator 2 13 respectively. The optical fiber ring 1 4 and optical fiber ring 2 18 can generate a ring-down pulse signal to drive coupler 1 5 and coupler 3 1 The optical signal inside chamber 4 circulates and rings down, allowing the photodetector 11 and host computer 12 to perform analysis. Optical isolator 4 and optical isolator 2 13 prevent reverse transmission of light. Since there is gas to be measured in gas chamber 1 9 and gas chamber 2 16, the optical signal changes when passing through SO2 sensor 8 and H2S sensor 15. The changed optical signal enters the combiner 10 through coupler 2 7 and coupler 4 17. The photodetector 11 and host computer 12 are turned on, and the ring-down signal output by the combiner 10 is read and stored. The ring-down signal is fitted to establish a linear relationship between the gas concentration and the ring-down signal, thereby achieving simultaneous detection of the two gases.

[0059] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A multi-gas simultaneous detection device based on an optical fiber ring cavity, characterized by: include, Signal generator (1); A laser (2) connected to the signal generator (1); at least two reaction units; an optical switch (3) connecting the laser (2) and the input end of the reaction unit; A beam combiner (10) connected to the output ends of all reaction units; a detection unit connected to the beam combiner (10); The optical signal emitted by the laser (2) can be diverted to the input ends of all reaction units through the optical switch (3), and the optical signal output from the output end of the reaction unit is processed by the beam combiner (10) and then transmitted to the detection unit for detection.

2. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 1, characterized in that: The reaction unit includes a SO2 reaction unit and a H2S reaction unit. The SO2 reaction unit includes a coupler 1 (5), and the H2S reaction unit includes a coupler 3 (14).

3. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 2, characterized in that: One end of the coupler 1 (5) is connected to the optical isolator 1 (6), and one end of the coupler 3 (14) is connected to the optical isolator 2 (13).

4. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 3, characterized in that: One end of the optical isolator 1 (6) is connected to the air chamber 1 (9), and one end of the optical isolator 2 (13) is connected to the air chamber 2 (16).

5. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 4, characterized in that: An SO2 sensor (8) is provided inside the gas chamber 1 (9), and an H2S sensor (15) is provided inside the gas chamber 2 (16).

6. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 5, characterized in that: One end of the SO2 sensor (8) is connected to a second coupler (7), and one end of the H2S sensor (15) is connected to a fourth coupler (17).

7. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 6, characterized in that: One end of the coupler 2 (7) is connected to the optical fiber ring 1 (4), and one end of the coupler 4 (17) is connected to the optical fiber ring 2 (18).

8. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 7, characterized in that: The optical fiber ring 1 (4) is connected to the coupler 1 (5), and the optical fiber ring 2 (18) is connected to the coupler 3 (14).

9. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 8, characterized in that: The coupler 2 (7) and the coupler 4 (17) are both connected to the beam combiner (10).

10. The multi-gas simultaneous detection device based on an optical fiber ring cavity according to claim 9, characterized in that: The detection unit comprises a photoelectric detector (11) and a host computer (12), and the photoelectric detector (11) is connected to the beam combiner (10).

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