A multi-component power utility fire gas detection system and method

Abstract

The embodiment of the application provides a kind of multi-component electric power facility fire gas detection system and method, belong to fire warning technical field.The system is integrated with optical path unit, gas path unit and electric control and data processing unit in metal shielding shell;Optical path unit includes light input module, ring-down cavity module and detection module;Gas path unit at least includes gas input module;Light input module is connected with electric control and data processing unit and ring-down cavity module respectively, ring-down cavity module is connected with detection module, and detection module is connected with electric control and data processing unit;Gas input module is connected with ring-down cavity module and electric control and data processing unit by the pipeline of Teflon material respectively.The embodiment of the application can provide a kind of fire gas detection system that can operate in industrial harsh environment.

Description

Technical Field

[0001] This application relates to the field of fire early warning technology, and in particular to a multi-component power facility fire gas detection system and method. Background Technology

[0002] Fires in power facilities are characterized by their high degree of concealment, rapid spread, and difficulty in extinguishing. During the incubation stage, the insulation materials undergo pyrolysis and release trace amounts of characteristic gases such as carbon monoxide, carbon dioxide, and acetylene. The concentration of these gases is usually in the range of ppb to ppm. The appearance of these gases is much earlier than open flames and smoke, making them the core markers for achieving ultra-early warning of fires.

[0003] Electrochemical sensors, semiconductor sensors, and catalytic combustion sensors are widely used in power field applications. Some oil-immersed transformers use gas chromatography (DGA) for dissolved gas analysis in the oil. These technologies generally have a detection sensitivity in the ppm range, slow response, short lifespan, and severe cross-sensitivity.

[0004] Existing cavity ring-down spectroscopy (CRDS) technology is mostly used in general scenarios such as environmental monitoring and medical testing, primarily for single-component detection. A few multi-component CRDS schemes are designed for atmospheric environments and have not been adapted and optimized for the special operating conditions and characteristic gas spectral lines of power facilities. The equipment is bulky (typically >100L) and has poor environmental tolerance, making it unsuitable for direct application in power industry sites with high electromagnetic interference, wide temperature and humidity ranges, and high levels of dust and oil pollution.

[0005] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0006] The main objective of this application is to propose a multi-component power facility fire gas detection system and method, aiming to provide a fire gas detection system that can operate in harsh industrial environments.

[0007] To achieve the above objectives, one aspect of this application provides a multi-component power facility fire gas detection system, the system comprising a metal shielding shell, within which an optical path unit, a gas path unit, and an electrical control and data processing unit are integrated; The optical path unit includes an optical input module, a ring-down resonant cavity module, and a detection module; The gas circuit unit includes at least a gas input module; The optical input module is connected to the electronic control and data processing unit, the optical input module is connected to the ring-down resonant cavity module, the ring-down resonant cavity module is connected to the detection module, and the detection module is connected to the electronic control and data processing unit. The gas input module is connected to the ring-down resonant cavity module through a Teflon pipe, and the electronic control and data processing unit is connected to the gas input module. The gas input module is used to input the gas to be tested into the ring-down resonant cavity module according to the second control signal of the electronic control and data processing unit; The optical input module is used to emit a multi-wavelength coupled beam according to the first control signal of the electronic control and data processing unit; The ring-down resonant cavity module is used to measure the optical ring-down signal of the multi-wavelength coupled beam in the gas under test; wherein, the gas under test includes at least several target gases; The detection module is used to receive the optical oscillation signal and convert the optical oscillation signal into an electrical signal; The electronic control and data processing unit is used to receive the electrical signal, calculate the information of each target gas based on the electrical signal, and output a graded alarm signal.

[0008] In some embodiments, the optical input module includes at least a multi-wavelength light source module, a wavelength division multiplexing module, and a modulation module; The multi-wavelength light source module is connected to the wavelength division multiplexing module, the wavelength division multiplexing module is connected to the modulation module, the modulation module is connected to the ring-down resonant cavity module, and the multi-wavelength light source module is connected to the electronic control and data processing unit. The multi-wavelength light source module is used to emit several lasers of different wavelengths according to the first control signal of the electronic control and data processing unit. The wavelength division multiplexing module is used to couple each of the lasers into the multi-wavelength coupled beam; The modulation module is used to modulate the multi-wavelength coupled beam.

[0009] In some embodiments, the modulation module includes an acousto-optic modulator and an optical collimator; The wavelength division multiplexing module is connected to the acousto-optic modulator, the acousto-optic modulator is connected to the optical collimator, and the optical collimator is connected to the ring-down resonant cavity module. The acousto-optic modulator is used to control the incident state of the multi-wavelength coupled beam. The optical collimator is used to collimate the multi-wavelength coupled beam.

[0010] In some embodiments, the gas input module includes a sample injection filtration module and a mass flow controller; The sample injection filtration module is connected to the mass flow controller via a Teflon pipe, the mass flow controller is connected to the ring-down resonant cavity module via a Teflon pipe, and the mass flow controller is connected to the electrical control and data processing unit. The sample introduction and filtration module is used to filter the gas to be tested. The mass flow controller is used to input the gas to be measured according to the second control signal of the electronic control and data processing unit.

[0011] In some embodiments, the sample introduction and filtration module includes a melt-blown filter element and a molecular sieve drying tube; The meltblown filter element is connected to the molecular sieve drying tube through a Teflon pipe, and the molecular sieve drying tube is connected to the mass flow controller through a Teflon pipe. The meltblown filter element is used to filter oil and dust from the gas to be tested. The molecular sieve drying tube is used to filter water vapor from the gas to be tested.

[0012] In some embodiments, the electronic control and data processing unit includes a main control module, a laser tuning module, and a high-speed acquisition module; The laser tuning module is connected to the optical input module, the main control module is connected to the laser tuning module, the main control module is connected to the gas input module, the main control module is connected to the high-speed acquisition module, and the high-speed acquisition module is connected to the detection module. The laser tuning module is used to output a first control signal based on the detection signal of the main control module to control the laser wavelength of the optical input module; The high-speed acquisition module is used to acquire the electrical signals of the detection module and send them to the main control module.

[0013] In some embodiments, the electronic control and data processing unit further includes an environmental monitoring module; The environmental monitoring module includes a pressure sensor and a temperature sensor; The pressure sensor is connected to the main control module, and the temperature sensor is connected to the main control module. The pressure sensor is used to collect the air pressure in the decaying resonant cavity of the decaying resonant cavity module. The temperature sensor is used to collect the temperature of the decaying resonant cavity of the decaying resonant cavity module.

[0014] In some embodiments, the main control module includes a single exponential fitting submodule for ringback time, a gas concentration inversion submodule, a temperature and humidity compensation submodule, and a temperature drift compensation submodule; The single-exponential fitting submodule for ring-down time is used to calculate the ring-down time of the multi-wavelength coupled beam in the gas under test based on the electrical signal received by the main control module. The gas concentration inversion submodule is used to calculate the gas volume fraction of each target gas based on the electrical signal received by the main control module; The temperature and humidity compensation submodule is used to calculate the environmental fluctuation error based on the air pressure of the decaying resonant cavity module and the temperature of the decaying resonant cavity module. The temperature drift compensation submodule is used to calculate the wavelength offset of the laser corresponding to each wavelength in the multi-wavelength coupled beam based on the temperature of the decaying resonant cavity of the decaying resonant cavity module.

[0015] In some embodiments, the gas path unit further includes an exhaust gas treatment module; The decaying resonant cavity module is connected to the exhaust gas treatment module through a Teflon pipe. The exhaust gas treatment module is used to filter the gas to be tested after being detected by the decaying resonant cavity module.

[0016] To achieve the above objectives, another aspect of this application provides a method for detecting fire gases in multi-component power facilities, applicable to any of the aforementioned multi-component power facility fire gas detection systems. The method includes: Emitting multi-wavelength coupled beams; The optical ring-down signal of the multi-wavelength coupled beam in the gas under test is measured; wherein the gas under test includes at least several target gases; The optical ring-down signal is then converted into an electrical signal; The information of each target gas is calculated based on the electrical signal, and a graded alarm signal is output.

[0017] The embodiments of this application include at least the following beneficial effects: This application provides a multi-component power facility fire gas detection system and method. This system integrates the optical path unit, gas path unit, and electronic control and data processing unit within a metal shielded housing, enabling the entire detection system to maintain stable operation in the high electromagnetic interference environment commonly found in power industry sites, thus improving the accuracy and reliability of the detection results. The optical input module emits a multi-wavelength coupled beam to the ring-down resonant cavity module based on the first control signal from the electronic control and data processing unit, allowing the ring-down resonant cavity module to simultaneously measure the optical ring-down signals of multiple target gases in the gas under test during a single detection process. The detection module converts the optical ring-down signal into an electrical signal, and the electronic control and data processing unit calculates the information of each target gas and outputs graded alarm signals, realizing the synchronous detection of multi-component gases, improving detection efficiency while reducing system complexity. The gas input module is connected to the ring-down resonant cavity module through a Teflon pipe, which significantly reduces the gas adsorption and residual effect and improves the accuracy of gas detection for power facility fires. At the same time, the combination of the metal shielding shell and the Teflon gas path enables the system to be directly deployed in harsh power industry sites with high electromagnetic interference, dust and oil pollution, and wide humidity and temperature variations, achieving scenario adaptation from general environmental monitoring to ultra-early warning of power facility fires. Attached Figure Description

[0018] Figure 1 This is a connection diagram of a multi-component power facility fire gas detection system provided in an embodiment of this application; Figure 2 This is a schematic diagram of the optical input module connection of a multi-component power facility fire gas detection system provided in an embodiment of this application; Figure 3 This is a schematic diagram of the modulation module connection of a multi-component power facility fire gas detection system provided in an embodiment of this application; Figure 4 This is a schematic diagram of the gas input module connection of a multi-component power facility fire gas detection system provided in an embodiment of this application; Figure 5 This is a schematic diagram of the connection of the sample introduction and filtration module of a multi-component power facility fire gas detection system provided in an embodiment of this application; Figure 6 This is a schematic diagram of the connection between the electrical control and data processing units of a multi-component power facility fire gas detection system provided in an embodiment of this application; Figure 7 This is a schematic diagram of the connection between the electrical control and data processing units of another multi-component power facility fire gas detection system provided in an embodiment of this application; Figure 8 This is a schematic diagram of the gas circuit unit connection of another multi-component power facility fire gas detection system provided in the embodiments of this application; Figure 9 This is a schematic diagram of the overall structure of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application; Figure 10 This is a schematic diagram of the optical path unit connection of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application; Figure 11 This is a schematic diagram of the gas path unit connection of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application; Figure 12 This is a schematic diagram of the connection between the electrical control and data processing units of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0020] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0021] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0023] Before providing a detailed description of the embodiments of this application, some of the nouns and terms involved in the embodiments of this application will be explained first. The nouns and terms involved in the embodiments of this application are subject to the following interpretations.

[0024] 1) Cavity ring-down spectroscopy (CRDS) is an ultra-sensitive detection technique based on the principle of molecular absorption spectroscopy. Its principle is as follows: a laser beam undergoes multiple reflections within a high-reflectivity resonant cavity, and the gas absorption coefficient is calculated by measuring the ring-down time required for the light intensity to decay to 1 / e of its initial value. Since the optical path can reach 1–10 km, the detection limit can reach the ppb or even ppt level.

[0025] 2) Wavelength division multiplexing (WDM) technology couples multiple laser beams of different wavelengths to the same optical path through a multiplexer, which is a key means to realize the synchronous detection of multi-component gas in a single resonant cavity.

[0026] Traditional sensors lack sufficient detection sensitivity and have poor early warning timeliness. Their detection limit is mostly at the ppm level, which cannot identify trace characteristic gases at the ppb level during the fire incubation stage. They are difficult to achieve true pre-disaster early warning and often only trigger alarms after open flames or smoke are produced, missing the best time to deal with the situation.

[0027] Electrochemical and semiconductor sensors generally suffer from cross-sensitivity, weak anti-interference ability, low field reliability, and are susceptible to temperature and humidity fluctuations, oil and dust interference in power sites. They also have high false alarm rates, short service life, and require frequent calibration and maintenance, making it difficult to meet the long-term unattended operation requirements of power facilities.

[0028] In addition, existing cavity ring-down spectroscopy equipment has insufficient multi-component detection capabilities, poor equipment adaptability, and is mostly single-component detection architecture, making it unable to simultaneously identify multiple fire characteristic gases; general optical detection equipment lacks electromagnetic shielding and weather resistance design, resulting in poor operational stability in power field environments with strong electromagnetic fields and wide temperature variations, and its large size makes it difficult to deploy in confined spaces such as switch cabinets and wind turbine towers.

[0029] Existing power gas detection solutions have limited application scenarios and are bulky. They are mostly designed for transformer oil faults and lack universal multi-component trace gas detection devices that can be adapted to various new power facilities such as photovoltaics, energy storage, and wind turbines. The devices are usually larger than 100L and cannot be deployed in small spaces such as switch cabinets and wind turbine towers.

[0030] In view of this, and addressing the shortcomings of existing power facility fire gas detection technologies, such as insufficient sensitivity, single component composition, and poor adaptability to on-site environments, this application provides a multi-component power facility fire gas detection system and method. This system integrates the optical path unit, gas path unit, and electronic control and data processing unit within a metal shielded enclosure, enabling the entire detection system to maintain stable operation in the high electromagnetic interference environment commonly found in power industry sites, thus improving the accuracy and reliability of the detection results. The optical input module emits a multi-wavelength coupled beam to the ring-down resonant cavity module based on the first control signal from the electronic control and data processing unit, allowing the ring-down resonant cavity module to simultaneously measure multiple components in a single detection process. The optical decay signal of the target gas in the gas to be tested is converted into an electrical signal by the detection module. The electronic control and data processing unit then calculates the information of each target gas and outputs graded alarm signals, realizing the synchronous detection of multiple components of gas, improving detection efficiency while reducing system complexity. The gas input module is connected to the decay resonant cavity module through a Teflon pipe, which significantly reduces the gas adsorption residue effect and improves the accuracy of gas detection for power facility fires. At the same time, the combination of the metal shielding shell and the Teflon gas path enables the system to be directly deployed in harsh power industry sites with high electromagnetic interference, dust and oil pollution, and wide humidity and temperature variations, achieving scenario adaptation from general environmental monitoring to ultra-early warning of power facility fires.

[0031] The core principle of this invention is as follows: based on the Lamb-Beer law and the theory of cavity ring-down spectroscopy, multiple laser beams corresponding to different gas characteristic absorption lines are coupled to the same Fabry-Perot (FP) resonant cavity using wavelength division multiplexing technology. By measuring the difference in the ring-down time of the laser in the cavity, the concentration of each component gas is inverted. At the same time, the gas path and electrical control structure are optimized for the power field conditions to ensure the long-term stable operation of the device.

[0032] The core formula is as follows: (1) in, For the time of decline, For the refractive index of the gas, For cavity length, At the speed of light, For the reflectivity of the endoscope, This is the gas absorption coefficient. It is determined by measuring the gas-containing decay time. With cavity decay time The difference, combined with the gas absorption cross-section parameters, is used to invert the gas volume fraction concentration.

[0033] Figure 1 This is a connection diagram of a multi-component power facility fire gas detection system provided in an embodiment of this application. The system includes a metal shielding shell, and an optical path unit, a gas path unit, and an electrical control and data processing unit are integrated inside the metal shielding shell. The optical path unit includes an optical input module, a ring-down resonant cavity module, and a detection module; The gas circuit unit includes at least a gas input module; The optical input module is connected to the electronic control and data processing unit, the optical input module is connected to the ring-down resonant cavity module, the ring-down resonant cavity module is connected to the detection module, and the detection module is connected to the electronic control and data processing unit. The gas input module is connected to the decaying resonant cavity module through a Teflon pipe, and the electronic control and data processing unit is connected to the gas input module. The gas input module is used to input the gas to be measured into the ring-down resonant cavity module according to the second control signal of the electronic control and data processing unit. The optical input module is used to emit a multi-wavelength coupled beam of light according to the first control signal from the electronic control and data processing unit; The ring-down resonant cavity module is used to measure the optical ring-down signal of a multi-wavelength coupled beam in a gas under test; wherein the gas under test includes at least several target gases; The detection module is used to receive optical ring-down signals and convert them into electrical signals; The electronic control and data processing unit is used to receive electrical signals, calculate the information of each target gas based on the electrical signals, and output graded alarm signals.

[0034] In some embodiments, the decaying resonant cavity module may be a short cavity (e.g., 22cm) or a long cavity (e.g., 58cm), and is not limited thereto.

[0035] In some embodiments, the detection module may use a photodetector for receiving signals, preferably an InGaAs type photodetector, but is not limited thereto.

[0036] In some embodiments, the aforementioned multi-component power facility fire gas detection system can be integrated into a metal enclosure with a volume of 40cm×37cm×20cm. The enclosure adopts an aluminum alloy shielding structure and has a conductive oxidation treatment on the surface to meet the electromagnetic compatibility (EMC) requirements of the power field, but is not limited thereto.

[0037] The system illustrated in this application integrates the optical path unit, gas path unit, and electronic control and data processing unit within a metal shielded housing. This allows the entire detection system to maintain stable operation in the high electromagnetic interference environment commonly found in power industry sites, improving the accuracy and reliability of detection results. The optical input module emits a multi-wavelength coupled beam to the ring-down resonant cavity module based on the first control signal from the electronic control and data processing unit. This enables the ring-down resonant cavity module to simultaneously measure the optical ring-down signals of multiple target gases in the gas to be tested during a single detection process. The detection module converts the optical ring-down signals into electrical signals, and the electronic control and data processing unit calculates the information of each target gas and outputs graded alarm signals. This achieves simultaneous detection of multiple components of gas, improving detection efficiency while reducing system complexity. The gas input module is connected to the ring-down resonant cavity module through a Teflon pipe, significantly reducing the gas adsorption and residual effect and improving the accuracy of gas detection for power facility fires. At the same time, the combination of the metal shielded housing and the Teflon gas path allows the system to be directly deployed in harsh power industry sites with high electromagnetic interference, dust, oil pollution, and wide humidity and temperature variations, achieving scenario adaptation from general environmental monitoring to ultra-early warning of power facility fires.

[0038] In some embodiments, please refer to Figure 2 , Figure 2 This is a schematic diagram of the optical input module connection of a multi-component power facility fire gas detection system provided in an embodiment of this application. The optical input module includes at least a multi-wavelength light source module, a wavelength division multiplexing module, and a modulation module. The multi-wavelength light source module is connected to the wavelength division multiplexing module, the wavelength division multiplexing module is connected to the modulation module, the modulation module is connected to the ring-down resonant cavity module, and the multi-wavelength light source module is connected to the electronic control and data processing unit. Among them, the multi-wavelength light source module is used to emit several lasers of different wavelengths according to the first control signal of the electronic control and data processing unit; Wavelength division multiplexing modules are used to couple individual laser beams into multi-wavelength coupled beams; The modulation module is used to modulate multi-wavelength coupled beams.

[0039] In some embodiments, the multi-wavelength light source module may be composed of several distributed feedback lasers, preferably butterfly distributed feedback (DFB) lasers.

[0040] In some embodiments, the wavelength division multiplexing module may employ a polarization-maintaining wavelength division multiplexer, preferably a dielectric thin-film polarization-maintaining wavelength division multiplexer (PM-WDM), but is not limited thereto.

[0041] In some embodiments, the modulation module is located at the incident end of the decaying resonant cavity module, and the detection module is located at the viewing end of the decaying resonant cavity module, but this is not limited to these embodiments.

[0042] In this embodiment, three butterfly distributed feedback (DFB) lasers are used as light sources. The center wavelength of each laser corresponds to the characteristic absorption spectrum of a characteristic gas of the electrical fire to be tested. Please refer to Table 1, which shows the setting parameters of each laser and its corresponding gas in this embodiment.

[0043] Table 1 Laser setup parameters and corresponding gases

[0044] A dielectric thin-film polarization-maintaining wavelength division multiplexer (PM-WDM) is used to couple multiple lasers of different wavelengths into a single composite beam. The channel insertion loss is ≤1dB, the isolation is ≥32dB, and the operating wavelength range covers 1550–1610nm. Using a PM-WDM instead of a conventional WDM ensures that the multiple lasers maintain polarization state consistency after coupling, which is a prerequisite for achieving high-precision resonant cavity mode matching.

[0045] The decaying resonant cavity is the core detection structure of CRDS technology, and its functions include: 1. Optical path amplification: High-reflectivity cavity mirrors (R≥99.99%) cause the laser to oscillate back and forth thousands of times within the cavity, resulting in an equivalent optical path of several kilometers, amplifying weak gas absorption signals by 10. 3 ~10 4 This achieves ppb-level trace gas detection.

[0046] 2. Frequency-selective resonance effect: The FP cavity structure resonates and enhances the laser of a specific wavelength, suppressing background noise and improving the signal-to-noise ratio.

[0047] 3. Time Measurement Conversion: Gas concentration measurement is converted into ring-down time measurement. Ring-down time is related to cavity mirror reflectivity, cavity length, and gas absorption characteristics. This is achieved by measuring the time constant of the exponential decay of the light intensity within the cavity after laser turn-off. This indirectly obtains gas concentration information.

[0048] 4. Calibration-free characteristics: The ring-down time measurement does not depend on the fluctuation of incident light intensity and has intrinsic calibration-free characteristics, making it suitable for long-term unattended operation in power fields.

[0049] In some embodiments, an FP resonant cavity is formed by two high-reflectivity cavity mirrors arranged coaxially opposite each other, with a fused silica substrate and a cavity mirror reflectivity ≥99.99%. The resonant cavity is available in two optional specifications: a 22cm short cavity suitable for deployment in confined spaces such as switchgear and wind turbine towers, and a 58cm long cavity suitable for scenarios with higher detection accuracy requirements such as substations. The cavity body is made of 304 stainless steel shielded shell with an IP65 protection rating, and has dustproof, waterproof and electromagnetic interference resistance capabilities.

[0050] In this embodiment, the decaying resonant cavity module preferably uses a short cavity (22cm). The short cavity breaks through the limitation of the cavity length of traditional CRDS devices >50cm. While maintaining the detection sensitivity at the ppb level, the device volume is compressed to 40cm×37cm×20cm, realizing deployment in a small space.

[0051] In this embodiment, the detector can be an InGaAs type photodetector with a response band of 1100–1700 nm, covering the entire wavelength range of the gas to be measured; the response bandwidth is 100 MHz, meeting the high-speed acquisition requirements of μs-level ring-down signals; the optical ring-down signal is converted into an electrical signal and then transmitted to the electronic control unit. Placing the detector at the transmission end of the resonant cavity rather than the reflection end avoids interference from backscattered light, ensuring that the acquired ring-down signal is pure intracavity transmitted light, thus improving the fitting accuracy.

[0052] This embodiment specifies the optical input module as a combination of a multi-wavelength light source module, a wavelength division multiplexing module, and a modulation module. The multi-wavelength light source module emits several lasers of different wavelengths according to the first control signal of the electronic control unit. The wavelength division multiplexing module couples each laser into a multi-wavelength coupled beam. The modulation module modulates the coupled beam, thereby realizing the synchronous transmission and state control of multi-wavelength lasers in a single optical path. This ensures that each wavelength beam has consistent incident conditions before entering the ring-down resonant cavity, providing a reliable optical basis for the effective excitation and accurate detection of subsequent multi-component gas signals.

[0053] In some embodiments, please refer to Figure 3 , Figure 3 This is a schematic diagram of the modulation module connection of a multi-component power facility fire gas detection system provided in an embodiment of this application. The modulation module includes an acousto-optic modulator and an optical collimator. The wavelength division multiplexing module is connected to the acousto-optic modulator, the acousto-optic modulator is connected to the optical collimator, and the optical collimator is connected to the ring-down resonant cavity module. Among them, the acousto-optic modulator is used to control the incident state of multi-wavelength coupled beams; Optical collimators are used to collimate multi-wavelength coupled beams.

[0054] In this embodiment, the multi-wavelength coupled beam is modulated by an acousto-optic modulator (AOM) and coupled into the resonant cavity through an optical collimator. The switching time of the acousto-optic modulator is ≤100ns, used to quickly turn off the laser and trigger the ring-down event. The acousto-optic modulator is driven by the TTL signal of the Zynq master control unit, and the driving frequency is adjustable (1~100Hz), adaptively adjusted according to the ring-down time. The optical collimator uses an achromatic lens group to collimate and shape the multi-wavelength coupled beam output from the acousto-optic modulator before coupling it into the front mirror of the resonant cavity, ensuring that the multi-wavelength coupled beam matches the resonant cavity mode and maintaining the single exponential decay characteristic of the ring-down signal.

[0055] This embodiment further concretizes the modulation module into a series structure consisting of an acousto-optic modulator and an optical collimator. The acousto-optic modulator has the physical characteristic of nanosecond-level switching time, which can quickly control the on / off state of multi-wavelength coupled beams to accurately trigger ring-down events. This ensures that the start time of each ring-down signal is clear and the off state is clean and crisp, thus providing a high-quality exponential decay waveform for accurate fitting of subsequent ring-down times. The optical collimator collimates the multi-wavelength coupled beams after passing through the acousto-optic modulator, so that the beams enter the ring-down resonant cavity module in the form of parallel light. This ensures that the beams will not suffer edge loss at the cavity mirrors due to excessive divergence angles during multiple reflections between the cavity mirrors, thereby maintaining the high precision of the resonant cavity and ensuring that the optical ring-down signal strictly conforms to the single exponential decay model, improving the accuracy of ring-down time fitting and the precision of concentration inversion.

[0056] In some embodiments, please refer to Figure 4 , Figure 4 This application provides a schematic diagram of the gas input module connection for a multi-component power facility fire gas detection system, which includes a sample injection filter module and a mass flow controller. The sample injection and filtration module is connected to the mass flow controller through a Teflon pipe. The mass flow controller is connected to the decay resonant cavity module through a Teflon pipe. The mass flow controller is also connected to the electrical control and data processing unit. The sample introduction and filtration module is used to filter the gas to be tested. The mass flow controller is used to input the gas to be measured based on the second control signal from the electronic control and data processing unit.

[0057] In this embodiment, stable injection of the gas to be tested is achieved through an injection filtration module and a mass flow controller. All pipelines are made of EP-grade polytetrafluoroethylene (Teflon) material, and the inner walls are polished (surface roughness Ra≤0.25μm) to minimize the residual effect of gas adsorption and improve the detection accuracy of low-concentration gases.

[0058] The gas path unit has undergone systematic optimization design to address the low concentration and strong polarity characteristics of the characteristic gases in power facility fires, as detailed below: Anti-adsorption pipeline design: All pipelines are made of EP-grade polytetrafluoroethylene (Teflon) with polished inner walls (surface roughness Ra≤0.25μm). Characteristic gases from power facility fires (such as CO, C2H2, etc.) are polar molecules, exhibiting severe adsorption effects in conventional metal or rubber pipelines, leading to distortion in the detection of low-concentration gases. Teflon material has extremely low surface energy (18-20mN / m), and combined with the inner wall polishing process, the residual gas adsorption effect can be reduced to <1%, and the gas response recovery time shortened to less than 30s, significantly improving the detection accuracy of ppb-level low-concentration gases.

[0059] Multi-stage filtration and dehumidification design: For power field environments with oil, dust, and high humidity (relative humidity up to 95%), it adopts a 5μm melt-blown filter + molecular sieve dual-stage purification to avoid the decrease in reflectivity and decay time drift caused by cavity contamination.

[0060] Precise flow control: The mass flow controller ensures a constant flow rate of 200 mL / min, eliminating the impact of flow rate fluctuations on detection and meeting quantitative detection requirements.

[0061] In this embodiment, a mass flow controller (MFC) is configured with a range of 0 to 500 mL / min, a control accuracy of ±1%FS, and a working flow rate of 200 mL / min to ensure the consistency of detection conditions.

[0062] This embodiment specifies the gas input module as consisting of a sample introduction filter module and a mass flow controller. The sample introduction filter module, located at the front end of the gas path, can remove impurities such as oil, dust, and moisture from the gas before it enters the ring-down resonant cavity module. This prevents impurity particles from adhering to the surface of the high-reflectivity cavity mirror, which would reduce the mirror's reflectivity and cause scattering interference to the ring-down signal. This extends the lifespan and maintenance cycle of the cavity mirror and ensures the quality of the optical ring-down signal. The mass flow controller precisely regulates the input flow rate of the gas to be tested according to the second control signal from the electronic control and data processing unit. This ensures that the gas flow rate entering the ring-down resonant cavity module remains constant at the set operating point during each test. This reduces the error introduced by changes in gas pressure within the cavity due to flow fluctuations in the ring-down time measurement and improves the consistency and repeatability of results between different test batches.

[0063] In some embodiments, please refer to Figure 5 , Figure 5 This is a schematic diagram of the connection of the sample introduction and filtration module of a multi-component power facility fire gas detection system provided in an embodiment of this application. The sample introduction and filtration module includes a melt-blown filter element and a molecular sieve drying tube. The meltblown filter element is connected to the molecular sieve drying tube through a Teflon pipe, and the molecular sieve drying tube is connected to the mass flow controller through a Teflon pipe. Among them, meltblown filter elements are used to filter oil and dust in the gas to be tested; Molecular sieve drying tubes are used to filter water vapor from the gas being tested.

[0064] In this embodiment, the sample inlet of the sample filtration module is equipped with a 5μm polypropylene meltblown filter to remove oil and dust from the air at the power site. In addition, a molecular sieve drying tube is configured as a water removal component to remove water vapor and avoid contaminating the endoscope and pipeline.

[0065] This embodiment uses a melt-blown filter element and a molecular sieve drying tube to form a filtration module. The melt-blown filter element has the characteristics of uniform pore size and high porosity, which can efficiently filter micron-sized oil mist and dust particles entrained in the gas to be tested, preventing solid or liquid contaminants from entering the decaying resonant cavity module and contaminating the cavity mirror. The molecular sieve material in the molecular sieve drying tube has a strong selective adsorption capacity for water molecules, which can reduce the water vapor content in the gas to be tested to a level that does not affect the spectral detection. This reduces the overlap and interference between water vapor molecules and target gas molecules on characteristic absorption lines, and also avoids water vapor condensing on the surface of the high-reflectivity cavity mirror to form a water film, which would cause a sharp drop in the cavity mirror reflectivity. This improves the detection stability and long-term reliability in the high-humidity environment of the power field.

[0066] In some embodiments, please refer to Figure 6 , Figure 6 This is a schematic diagram of the connection between the electrical control and data processing units of a multi-component power facility fire gas detection system provided in an embodiment of this application. The electrical control and data processing unit includes a main control module, a laser tuning module, and a high-speed acquisition module. The laser tuning module is connected to the optical input module, the main control module is connected to the laser tuning module, the main control module is connected to the gas input module, the main control module is connected to the high-speed acquisition module, and the high-speed acquisition module is connected to the detection module. Among them, the laser tuning module is used to output a first control signal based on the detection signal of the main control module to control the laser wavelength of the optical input module; The high-speed acquisition module is used to acquire electrical signals from the detection module and send them to the main control module.

[0067] In this embodiment, the Zynq heterogeneous chip is used as the main control core, integrating the main control module, laser tuning module and high-speed acquisition module.

[0068] The laser tuning module features high-precision temperature control, employing a TEC thermoelectric cooler with a temperature control accuracy of ±0.01℃, stabilizing the laser output wavelength; it uses a precision constant current source for current control with a control accuracy of ±0.01mA; and through a feedback control loop, it locks the laser wavelength to the center of the target gas absorption spectrum.

[0069] The hardware components of the laser tuning module include: a TEC thermoelectric cooler with a temperature control accuracy of ±0.01℃ to stabilize the laser output wavelength; a precision constant current source with a current control accuracy of ±0.01mA to adjust the laser output power and wavelength; a temperature sensor to monitor the laser operating temperature in real time (resolution 0.001℃); and a current sensor to monitor the laser drive current in real time (resolution 0.001mA).

[0070] The laser tuning module employs a two-stage wavelength locking strategy of "temperature coarse tuning + current fine tuning," as detailed below: Step 1, Initial Locking (Power-on Phase): The algorithm calculation module queries the center wavelength of the target gas absorption spectrum from the HITRAN database, and then sends the target temperature to the laser tuning module via the RS485 bus. and current Command; the temperature control PID loop of the laser tuning module stabilizes the laser to... (Within ±0.01℃); the current control circuit stabilizes the drive current to... (Within ±0.01mA range).

[0071] Step 2, Dynamic Locking (Operation Phase): Temperature and current sensors acquire the real-time status of the laser at a frequency of 10Hz; the acquired data is transmitted back to the PS terminal of the Zynq main control chip via the SPI interface; the "temperature drift compensation algorithm" in the algorithm calculation module calculates the wavelength offset in real time. : (2) in This is the temperature wavelength coefficient (typical value 0.1 nm / ℃). This is the current wavelength factor (typical value 0.002 nm / mA). If | If the value exceeds 0.001nm (exceeding the threshold), the algorithm module generates a correction instruction: (Temperature compensation amount); (3) (Current compensation amount); (4) The calibration command is sent to the laser tuning module via the RS485 bus. The PID controller of the laser tuning module performs temperature / current adjustment, thereby forming a closed-loop feedback to control the wavelength drift within ±0.001 nm.

[0072] The temperature fluctuation range in power field is large (-40℃ to +80℃), and the laser wavelength temperature coefficient is about 0.1nm / ℃. Without wavelength locking, the wavelength shift can reach ±12 nm, completely deviating from the gas absorption spectrum. This module controls the wavelength drift within ±0.001nm through high-precision temperature control and real-time feedback correction, ensuring long-term detection stability and enabling manual calibration-free operation in power field.

[0073] 2) High-speed acquisition module: A 16-bit, 100MSPS high-speed AD converter is used to sample the oscillation signal output by the photodetector at high speed to ensure the accuracy of oscillation time fitting.

[0074] In some other embodiments, the electrical control and data processing unit can also integrate a communication and interaction module. Equipped with standard industrial interfaces such as RS485 and Ethernet, it can be directly connected to a power facility fire early warning system; it also features a human-machine interface that supports on-site parameter setting, data viewing, and equipment calibration.

[0075] This embodiment incorporates a main control module, a laser tuning module, and a high-speed acquisition module within the electrical control and data processing unit. The laser tuning module, connected to the optical input module, precisely tunes and locks the output wavelengths of each laser within the optical input module. This ensures that the emission wavelength of each laser is always aligned with the center of the characteristic absorption spectral line of the corresponding target gas, reducing the likelihood of wavelength shift due to temperature drift in the wide temperature range of the power field. This improves the wavelength stability and detection accuracy of the detection system when deployed in power fields in all weather and seasons. The high-speed acquisition module, connected to the detection module, acquires the electrical signals output by the detection module at a high sampling rate. It can record complete and detailed waveforms of extremely short-duration ring-down signals, providing sufficient data point density for subsequent high-precision fitting of ring-down times, thus improving the resolution and accuracy of ppb-level trace gas concentration inversion. The main control module is connected to the laser tuning module, gas input module, and high-speed acquisition module to coordinate the timing actions of each module. This ensures that wavelength locking, gas injection, and ring-down signal acquisition work collaboratively according to the correct timing logic, guaranteeing the automation and standardization of the detection process.

[0076] In some embodiments, please refer to Figure 7 , Figure 7 This is a schematic diagram of the connection of the electrical control and data processing unit of another multi-component power facility fire gas detection system provided in an embodiment of this application. The electrical control and data processing unit also includes an environmental monitoring module. The environmental monitoring module includes pressure sensors and temperature sensors; The pressure sensor is connected to the main control module, and the temperature sensor is also connected to the main control module. Among them, the pressure sensor is used to collect the air pressure in the decaying resonant cavity of the decaying resonant cavity module; The temperature sensor is used to collect the temperature of the decaying resonant cavity in the decaying resonant cavity module.

[0077] This embodiment incorporates an environmental monitoring module with pressure and temperature sensors within the electrical control and data processing unit. These sensors are connected to the decaying resonant cavity module to collect real-time air pressure and temperature data. Simultaneously, the collected air pressure and temperature data are transmitted to the main control module, enabling it to obtain the true environmental state parameters at the decay time during concentration inversion calculations. The absorption spectral intensity, linewidth, and line shape of gas molecules change with temperature and pressure. Without environmental compensation, temperature and pressure fluctuations directly lead to systematic deviations in the concentration inversion results. This embodiment uses real-time collected temperature and pressure data as input parameters to the concentration inversion algorithm, dynamically correcting the absorption cross-section parameters. This effectively reduces the interference of environmental factors such as wide temperature variations and air pressure fluctuations in power field environments on detection accuracy, significantly improving the detection accuracy and environmental adaptability of the device in outdoor industrial sites.

[0078] In some embodiments, the main control module includes a single exponential fitting submodule for ringback time, a gas concentration inversion submodule, a temperature and humidity compensation submodule, and a temperature drift compensation submodule. Among them, the single exponential fitting submodule for ring-down time is used to calculate the ring-down time of the multi-wavelength coupled beam in the gas under test based on the electrical signal received by the main control module. The gas concentration inversion submodule is used to calculate the gas volume fraction of each target gas based on the electrical signal received by the main control module. The temperature and humidity compensation submodule is used to calculate the environmental fluctuation error based on the air pressure and temperature of the decaying resonant cavity module. The temperature drift compensation submodule is used to calculate the wavelength offset of each wavelength in the multi-wavelength coupled beam based on the temperature of the decaying resonator module.

[0079] In this embodiment, the main control module includes a single-exponential fitting submodule for ring-down time, a gas concentration inversion submodule, a temperature and humidity compensation submodule, and a temperature drift compensation submodule. It may also include an Allan variance analysis submodule, which can calculate the volume fraction of each gas component in real time and output a graded alarm signal based on the power fire early warning threshold. The algorithm functions of each module in the main control module are shown in Table 2.

[0080] Table 2

[0081] The ring-down time fitting algorithm is deployed on the Zynq PL to achieve hardware-level parallel acceleration, improving the fitting speed by more than 10 times and meeting the requirements of real-time detection.

[0082] This embodiment integrates at least four functional submodules into the main control module: a single-exponential fitting submodule for ring-down time, a gas concentration inversion submodule, a temperature and humidity compensation submodule, and a temperature drift compensation submodule. Among them, the single-exponential fitting submodule for ring-down time performs single-exponential fitting on the digital ring-down waveform acquired by the high-speed acquisition module to accurately extract the gas-containing ring-down time. The fitting process employs hardware-level parallel acceleration, enabling parameter extraction for a single ring-down event to be completed in an extremely short time, meeting the real-time requirements of fire early warning; the gas concentration inversion submodule is based on cavity ring-down time. With gas decay time The difference is used to calculate the volume fraction of each target gas by combining the Lambert-Beer law and the gas absorption cross-section parameters, thus achieving an accurate conversion from physical signal to chemical concentration. The temperature and humidity compensation submodule corrects the gas absorption cross-section parameters for temperature and pressure based on real-time environmental data from pressure and temperature sensors, eliminating measurement errors introduced by environmental fluctuations. The temperature drift compensation submodule dynamically corrects the slight shift in the laser emission wavelength based on real-time monitoring of the laser's operating temperature and current status, ensuring that the wavelength is always locked at the center of the absorption spectrum. The four submodules work together to form a complete closed loop at four levels: hardware accelerated fitting, accurate concentration inversion, environmental disturbance suppression, and wavelength drift compensation. Together, they ensure that the detection system can output the concentration information of each target gas in a long-term, stable, and accurate manner in the harsh environment of the power industry.

[0083] In some embodiments, please refer to Figure 8 , Figure 8 This is a schematic diagram of the gas circuit unit connection of another multi-component power facility fire gas detection system provided in an embodiment of this application. The gas circuit unit also includes an exhaust gas treatment module. The decaying resonant cavity module is connected to the exhaust gas treatment module through a Teflon pipe; The exhaust gas treatment module is used to filter the gas to be tested after being detected by the decaying resonant cavity module.

[0084] In this embodiment, the exhaust end of the decaying resonant cavity module is equipped with a tail gas treatment module that uses activated carbon and molecular sieve composite adsorption to treat the detected tail gas in a harmless manner, thereby preventing toxic gases (such as C2H2) from being directly emitted into the working environment.

[0085] This embodiment further adds an exhaust gas treatment module to the gas circuit unit. After the test is completed, the gas to be tested is introduced from the decay resonant cavity module into the exhaust gas treatment module through a Teflon pipe for harmless treatment. This allows the exhaust gas containing toxic and harmful components to be effectively adsorbed and purified before being discharged into the atmosphere, thus meeting the environmental protection and occupational safety requirements of the power facility site.

[0086] The following is a detailed description and explanation of the solutions in the embodiments of the present invention, using specific application examples: Example 1: Two-component trace gas detection device (CO / CO2).

[0087] This embodiment is designed for general power scenarios such as substations and energy storage power stations, and can simultaneously detect CO and CO2, two core early-stage fire characteristic gases. Specific implementation details are as follows: I. Hardware Configuration. Please refer to [link / reference]. Figure 9 , Figure 9 This is a schematic diagram of the overall structure of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application.

[0088] 1. For optical path unit connection, please refer to [link / reference]. Figure 10 , Figure 10 This is a schematic diagram of the optical path unit connection of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application.

[0089] (1) Light source: two butterfly-shaped DFB lasers with center wavelengths of 1565nm (corresponding to CO2 absorption line) and 1600nm (corresponding to CO absorption line), respectively, and linewidths of <2MHz. The pigtails are FC / PC polarization-maintaining interfaces.

[0090] (2) Wavelength division multiplexer: dielectric thin film type PM-WDM, operating band coverage 1550~1610nm, channel insertion loss ≤1dB, isolation ≥32dB.

[0091] (3) Resonant cavity: Short cavity design, cavity length 22cm, cavity mirror is a fused silica substrate high reflectivity mirror with reflectivity ≥99.99%; the cavity body is made of 304 stainless steel shielded shell with protection level IP65.

[0092] (4) Acousto-optic modulator: switching time ≤ 100ns, used to quickly turn off the laser and trigger a ring-down event.

[0093] (5) Photodetector: InGaAs type, response band 1100~1700nm, response bandwidth 100MHz.

[0094] 2. For gas circuit unit connection, please refer to [link / reference]. Figure 11 , Figure 11 This is a schematic diagram of the gas circuit unit connection of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application.

[0095] (1) Sample introduction filtration: 5μm polypropylene meltblown filter element + molecular sieve water removal component, suitable for dusty and high humidity field environment.

[0096] (2) Piping: EP grade Teflon piping, inner diameter 4mm, inner wall polished.

[0097] (3) Flow control: mass flow controller, range 0~500mL / min, control accuracy ±1%FS, set working flow rate 200mL / min.

[0098] (4) Exhaust gas treatment: activated carbon + molecular sieve composite adsorption module.

[0099] 3. For the connection between the electronic control unit and the data processing unit, please refer to [link / reference]. Figure 12 , Figure 12 This is a schematic diagram of the connection between the electrical control and data processing units of a multi-component power facility fire gas detection system provided in Embodiment 1 of this application.

[0100] (1) Main control: Xilinx Zynq-7020 heterogeneous chip, the PL end realizes hardware-level ring-down time fitting, and the PS end runs the main control program and concentration algorithm.

[0101] (2) Laser drive: temperature control accuracy ±0.01℃, current control accuracy ±0.01mA.

[0102] (3) Data acquisition: 16-bit AD, sampling rate 100MSPS.

[0103] (4) Communication interface: RS485, Ethernet, supports Modbus protocol.

[0104] II. Work Process.

[0105] 1) Initialization calibration: After the system is powered on, the laser is preheated for 30 minutes to reach a stable operating temperature and current, so that the wavelength is locked to the target absorption line; high-purity N2 is introduced to purge the resonant cavity for 30 minutes, and the cavity ring-down time is collected. Use it as a baseline to complete zero-point calibration.

[0106] 2) Sample introduction: The gas to be tested is filtered and the flow rate is controlled before being introduced into the resonant cavity gas chamber at a constant speed. The detection is started after the gas state in the cavity is stable.

[0107] 3) Ring-down signal acquisition: The acousto-optic modulator periodically and rapidly turns off the incident laser, and the photodetector acquires the exponentially decaying waveform of the light intensity in the cavity. The sampling time for a single ring-down event is about 100μs.

[0108] 4) Concentration inversion: The main control unit performs a single-exponential fitting on the decay curve to obtain the gas-bearing decay time. and cavity decay time ; The gas absorption coefficient is calculated based on the following: (5) in, The measured ringback curve was obtained by fitting the Levenberg-Marquardt algorithm. The cavity ring-off time is measured when filled with standard nitrogen (N2); Let be the refractive index of the gas, approximately taken as 1; The length of the resonant cavity is 22cm in this embodiment; =3.0×10 8 m / s, is the speed constant of light; is the gas absorption coefficient.

[0109] Gas concentration inversion based on Lamb-Beer's law: (6) in, The gas absorption cross section can be obtained from the HITRAN database (CO2 at 1565 nm). =1.2×10 -23 cm 2 / molecule, CO at 1600nm: =8.5×10 -24 cm 2 / molecule); The gas molecule number density is calculated based on the ideal gas law. Let be the volume fraction of the target gas, and be the quantity to be determined. The ideal gas law is as follows: (8) in, The internal air pressure is measured in real time by a pressure sensor. The temperature inside the cavity is measured in real time using a temperature sensor. =1.38×10 -23 J / K is the Boltzmann constant.

[0110] Temperature and humidity compensation: based on actual measured temperature and pressure Correcting the absorption cross section This eliminates measurement errors caused by environmental fluctuations.

[0111] 5) Result output: The detection results are displayed in real time and uploaded to the fire early warning platform. When the concentration exceeds the preset early warning threshold, a graded alarm signal is triggered.

[0112] III. Performance Test Results The performance of the device in this embodiment was verified using national standard gases under normal temperature and pressure laboratory conditions, and the results are as follows: Detection limits: Based on Allan analysis of variance, the detection limit for CO2 is 51 ppb, and the detection limit for CO is 85 ppb.

[0113] Detection accuracy: Within the range of 0 to 200 ppm, the repeatability RSD of CO2 measurement is ≤0.26%, and the detection accuracy is 180 ppb; within the range of 0 to 100 ppm, the repeatability RSD of CO measurement is ≤0.47%, and the detection accuracy is 170 ppb.

[0114] Linearity: The linear fit R of CO2 detection 2 =0.99914, CO detection linearity R 2 =0.99994.

[0115] Response time: T90 response time ≤ 30s.

[0116] Example 2: Three-component extended detection device (CO / CO2 / C2H2).

[0117] This embodiment is designed for oil-immersed transformers. Based on embodiment 1, it adds a DFB laser corresponding to the C2H2 characteristic spectral line, expanding it to three-component synchronous detection, which can simultaneously identify two types of transformer fault characteristic gases: overheating and discharge.

[0118] In terms of hardware configuration, a 1512nm DFB laser was added to the light source, corresponding to the characteristic absorption spectral line of C2H2, and replaced with a 3-channel polarization-maintaining wavelength division multiplexer to ensure efficient coupling and isolation of the three lasers.

[0119] The remaining hardware structure and workflow are the same as in Example 1, which can achieve accurate identification of early insulation faults in transformers.

[0120] This application also provides a method for detecting fire gases in multi-component power facilities, applicable to any of the aforementioned multi-component power facility fire gas detection systems. The method includes: Emitting multi-wavelength coupled beams; Measuring the optical ring-down signal of a multi-wavelength coupled beam in a gas under test; wherein the gas under test includes at least several target gases; The optical decay signal is converted into an electrical signal; The system calculates information about each target gas based on electrical signals and outputs graded alarm signals.

[0121] It is understood that the content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0122] This application provides a multi-component power facility fire gas detection system and method. The system integrates an optical path unit, a gas path unit, and an electronic control and data processing unit within a metal shielded enclosure, enabling the entire detection system to maintain stable operation in the high electromagnetic interference environment commonly found in power industry sites, thus improving the accuracy and reliability of the detection results. The optical input module emits a multi-wavelength coupled beam to the ring-down resonant cavity module based on the first control signal from the electronic control and data processing unit. This allows the ring-down resonant cavity module to simultaneously measure the optical ring-down signals of multiple target gases in the gas under test during a single detection process. The detection module then detects the optical ring-down signals. After the oscillation signal is converted into an electrical signal, the electronic control and data processing unit calculates the information of each target gas and outputs graded alarm signals, realizing the synchronous detection of multi-component gases, improving detection efficiency while reducing system complexity; the gas input module is connected to the oscillation resonant cavity module through a Teflon pipe, which significantly reduces the gas adsorption residue effect and improves the accuracy of gas detection for power facility fires; at the same time, the combination of the metal shielding shell and the Teflon gas path enables the system to be directly deployed in harsh power industry sites with high electromagnetic interference, dust and oil pollution, and wide humidity and temperature variations, achieving scenario adaptation from general environmental monitoring to ultra-early warning of power facility fires.

[0123] This application embodiment, through the fusion of wavelength division multiplexing and cavity ring-down spectroscopy, for the first time adapts ppb-level multi-component gas detection capabilities to power facility fire early warning scenarios. This not only solves the problems of insufficient sensitivity and high false alarm rate of traditional sensors, but also overcomes the limitations of general-purpose CRDS equipment, such as poor environmental adaptability and inability to be deployed in industrial settings. The device can achieve ultra-early identification of fire hazards without dismantling power equipment or interrupting operation, effectively reducing the risk of fires in power facilities and improving the safe operation level of new power systems. Therefore, this application embodiment possesses multiple beneficial effects.

[0124] Table 3 Performance Comparison of the System in this Application Embodiment with Traditional Sensors and General CRDS Devices

[0125] Benefit 1: Ultra-high detection sensitivity enables early warning of fires.

[0126] This invention is based on the principle of cavity ring-down spectroscopy. It utilizes a high-reflectivity resonant cavity (≥99.99%) to achieve multiple reflections of the laser within the cavity, resulting in an effective optical path of 1–10 km. Combined with a high-precision FP resonant cavity and a low-noise InGaAs photodetector, the detection limit can reach the ppb level (CO2 detection limit 51 ppb, CO detection limit 85 ppb). It can capture trace characteristic gas signals in the early stages of pyrolysis of insulating materials, providing fire warnings several hours to tens of hours earlier than traditional ppm-level sensors, thus offering a sufficient window for hazard mitigation.

[0127] Benefit 2: Simultaneous detection of multiple components improves the accuracy of fault diagnosis.

[0128] Wavelength division multiplexing (WDM) technology enables synchronous transmission of multi-wavelength lasers in a single resonant cavity, allowing for the simultaneous detection of multiple characteristic gases in electrical fires, such as CO, CO2, and C2H2, in a single sample introduction. Through multi-component concentration ratio analysis (e.g., C2H2 / CO ratio for identifying discharge faults, CO / CO2 ratio for identifying overheating faults), the type and severity of faults can be further identified, reducing the risk of misjudgment from a single indicator and achieving a leap from "alarm" to "fault diagnosis (location, characterization, and classification)."

[0129] Benefit 3: Strong environmental adaptability, suitable for on-site working conditions in the power industry.

[0130] To address the challenges of high electromagnetic interference, wide temperature and humidity range (-40℃ to +80℃), and heavy dust and oil contamination in power applications, three adaptive structures were optimized: a miniaturized shielding cavity, an anti-adsorption Teflon gas path, and an integrated anti-interference electronic control system.

[0131] Miniaturized shielding cavity: 304 stainless steel shielding shell + aluminum alloy shielding chassis, meeting the electromagnetic compatibility (EMC) requirements of power field.

[0132] Anti-adsorption Teflon gas path: EP grade polytetrafluoroethylene pipeline (inner wall polishing Ra≤0.25μm), reducing the residual effect of gas adsorption to <1%.

[0133] Integrated anti-interference electronic control system: Zynq heterogeneous chip + high-precision temperature control feedback (±0.01℃) to maintain wavelength locking accuracy in a wide temperature range.

[0134] It can operate stably for a long time in harsh industrial environments, and the maintenance cycle is extended from 3 to 6 months in the traditional solution to more than 1 year.

[0135] Benefit 4: Miniaturized design, adaptable to various deployment scenarios.

[0136] By employing a short resonant cavity design (e.g., 22cm cavity length) and optimized optical path integration, the device's volume is compressed to 40cm×37cm×20cm (approximately 30L), which is only 1 / 3 to 1 / 5 of traditional CRDS equipment. It can be flexibly deployed in confined spaces such as switch cabinets, wind turbine towers, and energy storage battery compartments, solving the pain point of general-purpose CRDS equipment not being able to fit or be placed in such spaces.

[0137] Benefit 5: High specificity, low false alarms, and low total lifecycle cost.

[0138] Based on the detection principle of molecular characteristic absorption spectroscopy, this method offers high gas identification specificity with virtually no cross-interference. The optical detection device has no consumable components, eliminating the need for frequent calibration and sensor replacement, resulting in significantly lower overall lifecycle maintenance costs compared to traditional electrochemical / semiconductor sensing solutions.

[0139] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0140] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0141] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0142] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0143] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0144] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0145] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0146] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0147] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0148] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0149] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A multi-component power facility fire gas detection system, characterized in that, The system includes a metal shielding shell, within which an optical path unit, a pneumatic path unit, and an electronic control and data processing unit are integrated. The optical path unit includes an optical input module, a ring-down resonant cavity module, and a detection module; The gas circuit unit includes at least a gas input module; The optical input module is connected to the electronic control and data processing unit, the optical input module is connected to the ring-down resonant cavity module, the ring-down resonant cavity module is connected to the detection module, and the detection module is connected to the electronic control and data processing unit. The gas input module is connected to the ring-down resonant cavity module through a Teflon pipe, and the electronic control and data processing unit is connected to the gas input module. The gas input module is used to input the gas to be tested into the ring-down resonant cavity module according to the second control signal of the electronic control and data processing unit; The optical input module is used to emit a multi-wavelength coupled beam according to the first control signal of the electronic control and data processing unit; The ring-down resonant cavity module is used to measure the optical ring-down signal of the multi-wavelength coupled beam in the gas under test; wherein, the gas under test includes at least several target gases; The detection module is used to receive the optical oscillation signal and convert the optical oscillation signal into an electrical signal; The electronic control and data processing unit is used to receive the electrical signal, calculate the information of each target gas based on the electrical signal, and output a graded alarm signal.

2. The multi-component power facility fire gas detection system according to claim 1, characterized in that, The optical input module includes at least a multi-wavelength light source module, a wavelength division multiplexing module, and a modulation module; The multi-wavelength light source module is connected to the wavelength division multiplexing module, the wavelength division multiplexing module is connected to the modulation module, the modulation module is connected to the ring-down resonant cavity module, and the multi-wavelength light source module is connected to the electronic control and data processing unit. The multi-wavelength light source module is used to emit several lasers of different wavelengths according to the first control signal of the electronic control and data processing unit. The wavelength division multiplexing module is used to couple each of the lasers into the multi-wavelength coupled beam; The modulation module is used to modulate the multi-wavelength coupled beam.

3. The multi-component power facility fire gas detection system according to claim 2, characterized in that, The modulation module includes an acousto-optic modulator and an optical collimator; The wavelength division multiplexing module is connected to the acousto-optic modulator, the acousto-optic modulator is connected to the optical collimator, and the optical collimator is connected to the ring-down resonant cavity module. The acousto-optic modulator is used to control the incident state of the multi-wavelength coupled beam. The optical collimator is used to collimate the multi-wavelength coupled beam.

4. The multi-component power facility fire gas detection system according to claim 1, characterized in that, The gas input module includes a sample injection filtration module and a mass flow controller; The sample injection filtration module is connected to the mass flow controller via a Teflon pipe, the mass flow controller is connected to the ring-down resonant cavity module via a Teflon pipe, and the mass flow controller is connected to the electrical control and data processing unit. The sample introduction and filtration module is used to filter the gas to be tested. The mass flow controller is used to input the gas to be measured according to the second control signal of the electronic control and data processing unit.

5. The multi-component power facility fire gas detection system according to claim 4, characterized in that, The sample introduction and filtration module includes a melt-blown filter element and a molecular sieve drying tube; The meltblown filter element is connected to the molecular sieve drying tube through a Teflon pipe, and the molecular sieve drying tube is connected to the mass flow controller through a Teflon pipe. The meltblown filter element is used to filter oil and dust from the gas to be tested. The molecular sieve drying tube is used to filter water vapor from the gas to be tested.

6. The multi-component power facility fire gas detection system according to claim 1, characterized in that, The electronic control and data processing unit includes a main control module, a laser tuning module, and a high-speed acquisition module; The laser tuning module is connected to the optical input module, the main control module is connected to the laser tuning module, the main control module is connected to the gas input module, the main control module is connected to the high-speed acquisition module, and the high-speed acquisition module is connected to the detection module. The laser tuning module is used to output a first control signal based on the level signal of the main control module to control the laser wavelength of the optical input module; The high-speed acquisition module is used to acquire the electrical signals of the detection module and send them to the main control module.

7. The multi-component power facility fire gas detection system according to claim 6, characterized in that, The electronic control and data processing unit also includes an environmental monitoring module; The environmental monitoring module includes a pressure sensor and a temperature sensor; The pressure sensor is connected to the main control module, and the temperature sensor is connected to the main control module. The pressure sensor is used to collect the air pressure in the decaying resonant cavity of the decaying resonant cavity module. The temperature sensor is used to collect the temperature of the decaying resonant cavity of the decaying resonant cavity module.

8. The multi-component power facility fire gas detection system according to claim 7, characterized in that, The main control module includes a single exponential fitting submodule for ringback time, a gas concentration inversion submodule, a temperature and humidity compensation submodule, and a temperature drift compensation submodule. The single-exponential fitting submodule for ring-down time is used to calculate the ring-down time of the multi-wavelength coupled beam in the gas under test based on the electrical signal received by the main control module. The gas concentration inversion submodule is used to calculate the gas volume fraction of each target gas based on the electrical signal received by the main control module; The temperature and humidity compensation submodule is used to calculate the environmental fluctuation error based on the air pressure of the decaying resonant cavity module and the temperature of the decaying resonant cavity module. The temperature drift compensation submodule is used to calculate the wavelength offset of the laser corresponding to each wavelength in the multi-wavelength coupled beam based on the temperature of the decaying resonant cavity of the decaying resonant cavity module.

9. The multi-component power facility fire gas detection system according to claim 1, characterized in that, The gas path unit also includes an exhaust gas treatment module; The decaying resonant cavity module is connected to the exhaust gas treatment module through a Teflon pipe. The exhaust gas treatment module is used to filter the gas to be tested after being detected by the decaying resonant cavity module.

10. A method for detecting multi-component fire gases in power facilities, characterized in that, The method, applied to the multi-component power facility fire gas detection system as described in any one of claims 1 to 9, comprises: Emitting multi-wavelength coupled beams; The optical ring-down signal of the multi-wavelength coupled beam in the gas under test is measured; wherein the gas under test includes at least several target gases; The optical ring-down signal is then converted into an electrical signal; The information of each target gas is calculated based on the electrical signal, and a graded alarm signal is output.

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