A laser micro-water detection device based on the principle of spectroscopy and taking water vapor in the atmosphere as a reference

Abstract

The present invention relates to the field of gas detection technology for power equipment, and in particular to a laser micro-water detection device based on the principle of spectrometry and taking water vapor in the atmosphere as a reference, comprising a light source, a closed pipe, a closed air chamber, an open air chamber and a digital signal processing unit, wherein the light source is connected to the closed pipe through an incident device, the other end of the closed pipe is connected to the closed air chamber, an open air chamber is arranged below the closed air chamber, a spectrometer is installed in the closed air chamber, a main detector is installed in the closed air chamber, a reference detector is installed in the open air chamber, and the main detector and the reference detector are electrically connected to the digital signal processing unit; its beneficial effect: based on the optimization of the present invention, the accuracy of data is improved. Compared with traditional time-sharing data acquisition, dual-channel real-time data acquisition is adopted to reduce external interference factors as much as possible, which can ensure accurate stability for long-term operation and accurately identify trace water vapor signals.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection for electric power equipment, and in particular to a laser micro-water detection device based on the principle of spectroscopy and taking water vapor in the atmosphere as a reference. Background Art

[0002] In the power industry, sulfur hexafluoride gas (SF6) is widely used in high-voltage switches and their equipment as an insulating and arc-extinguishing medium, but water vapor has a huge impact on the performance of SF6. Due to the influence of trace water vapor, arcs, corona, spark discharge and other factors, SF6 gas will decompose. Its decomposition products will become corrosive electrolytes when they encounter moisture, corroding high-voltage switches and their equipment, and at the same time produce some highly toxic decomposition products: such as SF4, S2F2, S2F10, SOF2, HF and S02. They will irritate the skin, eyes, and mucous membranes. If inhaled in large quantities, they will also cause dizziness and pulmonary edema, and even cause death. Therefore, detecting trace water vapor in power equipment is of great significance to the safe operation of power equipment and environmental protection.

[0003] The laser micro-water detection device uses tunable semiconductor laser absorption spectroscopy technology TDLAS. The detection beam can detect the characteristic absorption line of water vapor near 1397nm in the near-infrared spectrum to achieve synchronous measurement of water vapor. However, due to the special requirements of high-voltage switches and their equipment, it is necessary to accurately measure the concentration of trace water vapor. Usually, due to comprehensive factors such as light source wavelength and circuit device drift, the laser micro-water detection device works at extremely low water vapor concentration for a long time and cannot accurately identify trace water vapor signals. Summary of the invention

[0004] The purpose of the present invention is to address the problems existing in the prior art and to provide a laser micro-water detection device based on the principle of spectroscopy and taking water vapor in the atmosphere as a reference. In the case of a single light source module output, a method of using water vapor in the atmosphere as an auxiliary reference light path is added to eliminate the influence of comprehensive factors such as light source wavelength and circuit device drift, so that the device can accurately identify trace water vapor signals even under extremely low water vapor concentrations, thereby ensuring safe and reliable operation of electrical equipment.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A laser micro-water detection device based on the spectroscopic principle and taking water vapor in the atmosphere as a reference, characterized in that it includes a light source, a closed pipe, a closed air chamber, an open air chamber and a digital signal processing unit, the light source is connected to the closed pipe through an incident device, the other end of the closed pipe is connected to the closed air chamber, an open air chamber is arranged below the closed air chamber, a spectroscopic device is installed in the closed air chamber, a main detector is installed in the closed air chamber, a reference detector is installed in the open air chamber, and the main detector and the reference detector are electrically connected to the digital signal processing unit.

[0007] After the light source is collimated and focused, the light beam is directed through an incident device, through a sealed pipe, and then split by a light splitting device in a closed air chamber.

[0008] One beam is split to the main detector to measure the water vapor content in the SF6 gas in the pipeline; the other beam passes through a sealed window piece, splits to an external open gas chamber, and splits to a reference detector to use the water vapor in the atmosphere as a reference.

[0009] The light splitting device is beneficial to the polarization effect of the oblique incident light source, achieving the effect of splitting the light source into two.

[0010] The light splitting device outputs two light beams, horizontal and vertical, wherein the horizontal light beam is a main measuring light path with a light splitting ratio of 80%; the vertical light beam is an auxiliary reference light path with a light splitting ratio of 20%.

[0011] The main measurement optical path has no water vapor signal or the water vapor signal is extremely low, so the splitting ratio is appropriately increased to improve the signal strength; the reference optical path uses water vapor in the atmosphere as a reference, and the signal strength is relatively high, so the splitting ratio is appropriately reduced.

[0012] The light splitting device is a light splitter or a light splitting prism, which splits the light source into two.

[0013] The circuit optimizes the acquisition process, changes the operating temperature of the laser and the injected current to change the output wavelength of the light source. After locking the central wavelength of the laser, synchronous data acquisition is performed on the main detector in the measurement optical path and the reference detector in the reference optical path, and then data processing is performed on the two signals. If the position of the maximum point of the second harmonic data of the reference optical path is consistent, the data of the maximum point of the second harmonic of the current main detector is obtained, otherwise the central wavelength of the laser is re-locked, and tracking calculations are continued until it is suitable, and then the water vapor concentration is calculated according to the Lambert-Beer law.

[0014] At the same time, the sealed structure design has excellent sealing performance for the internal measuring gas, which can be recycled and reused to ensure a long life cycle.

[0015] The present invention has the following beneficial effects: Based on the optimization of the present invention, the accuracy of data is improved. Compared with the traditional time-sharing data acquisition, the dual-channel real-time data acquisition is adopted to reduce external interference factors as much as possible, ensure the accurate stability of long-term operation, and accurately identify trace water vapor signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 It is a working principle diagram of the present invention;

[0018] Figure 3 This is a working principle diagram of the wind-solar device in the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] Example 1

[0021] A laser micro-water detection device based on the principle of spectroscopy using water vapor in the atmosphere as a reference, such as Figure 1 and Figure 2 As shown, it is characterized by: comprising a light source, a closed pipe, a closed air chamber, an open air chamber and a digital signal processing unit, the light source is connected to the closed pipe through an incident device, the other end of the closed pipe is connected to the closed air chamber, an open air chamber is arranged below the closed air chamber, a spectrometer is installed in the closed air chamber, a main detector is installed in the closed air chamber, a reference detector is installed in the open air chamber, and the main detector and the reference detector are electrically connected to the digital signal processing unit.

[0022] After the light source is collimated and focused, the light beam is sent through the incident device to pass through the closed pipe and then split by the spectrometer in the closed air chamber. One beam is split to the main detector to measure the water vapor content in the SF6 gas in the pipe; the other beam is split through the closed window piece to the external open air chamber and then to the reference detector to use the water vapor in the atmosphere as a reference.

[0023] The light splitting device is a light splitter or a light splitting prism, which splits the light source into two.

[0024] The light splitting device is beneficial to the polarization effect of the oblique incident light source, achieving the effect of splitting the light source into two.

[0025] The spectroscopic device outputs two light beams, horizontal and vertical, and the horizontal beam is the main measuring light path with a splitting ratio of 80%; the vertical beam is the auxiliary reference light path with a splitting ratio of 20%. The main measuring light path has no water vapor signal or the water vapor signal is extremely low, so the splitting ratio is appropriately increased to increase the signal strength; the reference light path uses water vapor in the atmosphere as a reference, and the signal strength is relatively high, so the splitting ratio is appropriately reduced.

[0026] Example 2

[0027] like Figure 2 As shown, the circuit optimizes the acquisition process, changes the operating temperature of the laser and the injected current to change the output wavelength of the light source. After locking the central wavelength of the laser, synchronous data acquisition is performed on the main detector in the measurement optical path and the reference detector in the reference optical path, and then data processing is performed on the two signals. If the position of the maximum point of the second harmonic data of the reference optical path is consistent, the data of the maximum point of the second harmonic of the current main detector is obtained, otherwise the central wavelength of the laser is re-locked, and tracking calculations are continued until it is suitable, and then the water vapor concentration is calculated according to the Lambert-Beer law.

[0028] At the same time, the sealed structure design has excellent sealing performance for the internal measuring gas, which can be recycled and reused to ensure a long life cycle.

[0029] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A working process of a laser micro-water detection device based on the principle of spectroscopy and taking water vapor in the atmosphere as a reference, a laser micro-water detection device based on the principle of spectroscopy and taking water vapor in the atmosphere as a reference, characterized in that: The laser micro-water detection device comprises a light source, a closed pipe, a closed air chamber, an open air chamber and a digital signal processing unit. The light source is connected to the closed pipe through an incident device, the other end of the closed pipe is connected to the closed air chamber, an open air chamber is arranged below the closed air chamber, a spectrometer is installed in the closed air chamber, a main detector is installed in the closed air chamber, a reference detector is installed in the open air chamber, and the main detector and the reference detector are electrically connected to the digital signal processing unit; after the light source is collimated and focused, the light beam is sent through the closed pipe through the incident device and then sent to the digital signal processing unit. The spectrometer is used to perform spectroscopic analysis in a closed gas chamber; one beam is split to the main detector to measure the water vapor content in the SF6 gas in the pipeline; the other beam is split through a sealed window piece to an external open gas chamber and then to a reference detector to use the water vapor in the atmosphere as a reference; the spectrometer outputs two beams, horizontal and vertical, and the horizontal beam is the main measurement optical path; the main measurement optical path has no water vapor signal or the water vapor signal is extremely low, and the splitting ratio is appropriately increased to improve the signal strength; the reference optical path uses the water vapor in the atmosphere as a reference, and the signal strength is relatively high, and the splitting ratio is appropriately reduced; The working process is specifically as follows: By optimizing the acquisition process in the circuit, the operating temperature of the laser and the injected current are changed to change the output wavelength of the light source. After locking the central wavelength of the laser, the main detector in the measurement optical path and the reference detector in the reference optical path are synchronously collected, and then the two signals are processed. If the position of the maximum point of the second harmonic data of the reference optical path is consistent, the second harmonic maximum point data of the current main detector is obtained, otherwise the laser center wavelength is re-locked and the tracking calculation is continued until it is suitable, and then the water vapor concentration is calculated according to the Lambert-Beer law.

2. A laser micro-water detection device based on the principle of spectroscopy and taking water vapor in the atmosphere as a reference, characterized in that: The working process of the laser micro-water detection device based on the spectroscopic principle and taking water vapor in the atmosphere as a reference as claimed in claim 1 is adopted, wherein the spectroscopic device is beneficial to the polarization effect of the oblique incident light source, thereby achieving the effect of splitting the light source into two.

3. The laser micro-water detection device based on the spectroscopic principle and taking water vapor in the atmosphere as a reference according to claim 2, characterized in that: The horizontal light beam is the main measuring light path, and the splitting ratio is 80%; the vertical light beam is the auxiliary reference light path, and the splitting ratio is 20%.

4. A laser micro-water detection device based on the spectroscopic principle and taking water vapor in the atmosphere as a reference according to claim 2 or 3, characterized in that: The light splitting device is a light splitter or a light splitting prism, which splits the light source into two.

Images