A Cu 2+ - Fluoroboron dipyrrole complex probe and its application in GIS partial discharge detection

Abstract

This invention belongs to the field of fluorescent fiber optic sensing technology, specifically relating to a Cu 2+ ⁻-Fluoroboron dipyrrole complex probe and its application in GIS partial discharge detection. This invention successfully introduces chlorine atoms into the pyrrole ring position of the BODIPY core, and utilizes the nitrogen atoms on the two pyridine rings and the central amino nitrogen atom in the DPA to introduce Cu from three directions. 2+ The tightly fixed chelate ring structure at the center helps improve the stability of the probe in the SF6 decomposition product environment, while achieving a higher signal-to-noise ratio and a lower detection limit; the Cu of this invention 2+ The -fluoroboron dipyrrole complex probe is in a "fluorescence-off" state due to the fluorescence quenching effect of copper ions. However, upon specific reaction with H₂S, Cu... 2+ The H2S in the gas is depleted to form CuS precipitate, and the probe recovers the strong green fluorescence characteristic of BODIPY, thus enabling the qualitative and quantitative detection of H2S in the gas to be tested. The detection accuracy is high, the detection limit can reach the ppb level, and the anti-interference ability is strong.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent fiber optic sensing technology, specifically the field of GIS partial discharge detection technology, and more specifically, relates to a Cu... 2+ - Fluoroboron dipyrrole complex probe and its application in GIS partial discharge detection. Background Technology

[0002] Gas-insulated switchgear (GIS) has become a key piece of equipment in modern power systems due to its compact structure and reliable operation. The GIS cavity is typically filled with sulfur hexafluoride (SF6) gas as an insulating and arc-quenching medium. However, during long-term operation, partial discharge may occur inside the GIS cavity due to manufacturing defects, improper installation, or insulation aging. Partial discharge decomposes the SF6 gas, producing a series of sulfur-containing decomposition products, such as hydrogen sulfide (H2S) and sulfur dioxide (SO2). These decomposition products are not only a significant indicator of GIS insulation degradation but also further accelerate the corrosion of the insulating materials, ultimately leading to equipment failure and seriously threatening power grid safety.

[0003] Currently, detection methods for partial discharge in GIS mainly include pulsed current method, ultra-high frequency method, and ultrasonic method. Although these methods are widely used, they still have limitations in practical applications: the pulsed current method is susceptible to electromagnetic interference in the field; the ultra-high frequency method has strict requirements for sensor placement; and the ultrasonic method suffers severe signal attenuation in the complex structure of GIS. Furthermore, these methods primarily focus on detecting the physical phenomena of discharge, making it difficult to achieve in-situ, quantitative identification of specific fault gases caused by chemical degradation of insulating materials. While existing technologies include methods for detecting partial discharge optical signals using fluorescent optical fibers (such as CN116879688A), these mainly respond to the broad-spectrum optical signal generated by the discharge itself, lacking specific identification of key fault characteristic gases (such as H2S), and thus failing to accurately determine the fault type and severity. Additionally, according to existing patents, although methods for detecting hydrogen sulfide ions (HS-H2S) have been developed... - Fluorescent probes (such as CN103013496B) are available, but they are mainly targeted at H&R in liquid biological systems or environmental water samples. - The detection probe design, performance verification, and application scenarios are all centered around the aqueous environment, and cannot be directly applied to the gas environment. Therefore, it cannot be used for in-situ and online monitoring of H2S, a key fault characteristic gas in gas-insulated switchgear (GIS) equipment.

[0004] Therefore, there is an urgent need to develop a new technology capable of highly selective and sensitive detection of key decomposition products of SF6 partial discharge. Fluorescent fiber optic sensing technology, combining specific chemical recognition with fiber optic signal transmission, offers a potential solution to this problem. However, developing a sensing probe and detection system that can generate specific fluorescent responses to specific gases (such as H2S) in GIS fault environments and operate stably in the complex internal environments of electrical equipment remains a current technological bottleneck. Summary of the Invention

[0005] To address the lack of highly selective and sensitive detection technologies for key decomposition products of partial discharge in GIS in existing technologies, the present invention aims to provide a Cu 2+ - Fluoroboron dipyrrole complex probe and its application in GIS partial discharge detection: By introducing chlorine atoms into the pyrrole ring of the probe's BODIPY core, the chemical stability of the probe is enhanced, making it less susceptible to degradation in the SF6 decomposition product environment and extending its lifespan; when Cu in the probe... 2+ After being captured by H2S, BODIPY's fluorescence recovery is more thorough and rapid, which helps to achieve a higher signal-to-noise ratio and a lower detection limit, thereby addressing the shortcomings of existing detection methods in the specific identification and quantitative analysis of H2S gas.

[0006] Based on the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a Cu 2+ -Fluoroboropyrrole complex probe, Cu 2+ - The fluoroboron dipyrrole complex probe is formed by complexing the BODIPY-DPA ligand with divalent copper ions, wherein the pyrrole ring substituent in the BODIPY-DPA ligand is a chlorine atom; Cu 2+ The chemical structure of the -fluoroboron dipyrrole complex probe is as follows: .

[0007] This invention Cu 2+ The fluorinated boron dipyrrole complex probe retains a strongly electron-bearing chlorine atom (-Cl) at the pyrrole ring position of the BODIPY core. The introduction of this chlorine atom effectively reduces the electron cloud density of the BODIPY core through an electron-withdrawing effect, thus significantly improving its chemical stability and making it less susceptible to degradation in the SF6 decomposition product environment, resulting in a longer probe lifespan. Furthermore, when Cu in the probe... 2+ After being captured by H2S, BODIPY's fluorescence recovery is more thorough and rapid, which helps to achieve a higher signal-to-noise ratio and a lower detection limit.

[0008] Secondly, the present invention provides the above-mentioned Cu 2+ The preparation method of the fluorine-boron dipyrrole complex probe includes the following steps: (1) Preparation of chlorinated BODIPY, the method is as follows: 4-Chloro-2-benzoyl-1H-pyrrole was reacted with phosphorus oxychloride in an anhydrous reaction medium at low temperature and under an inert atmosphere to synthesize the Vilsmeier-Haack active intermediate. 2,4-Dimethyl-1H-pyrrole, triethylamine, and boron trifluoride diethyl ether were added sequentially to the Vilsmeier-Haack active intermediate and the reaction was continued until TLC monitoring showed complete formation of a strongly fluorescent product. The reaction product was subjected to fluorescence quenching, crude extraction, and purification to obtain an orange-red solid compound with a metallic luster, namely chloroBODIPY, also known as a derivative of the BODIPY core structure. In the above-mentioned synthesis of the BODIPY nucleus, the electrophile 4-chloro-2-benzoyl-1H-pyrrole is first activated under the action of phosphorus oxychloride, and then undergoes condensation with the nucleophile 2,4-dimethyl-1H-pyrrole to initially construct a dipyrrolemethane skeleton structure. Subsequently, triethylamine is added as an acid-binding agent to assist in the deprotonation of the pyrrole nitrogen atoms, so that the two nitrogen atoms can tightly "hold" the boron atoms in the subsequently added boron trifluoride, completing the fluorine-boron complexation reaction. This step locks the originally flexible dipyrrole skeleton into a rigid coplanar tricyclic structure, endowing the BODIPY nucleus molecule with excellent fluorescence properties.

[0009] (2) Preparation of BODIPY-DPA ligand compounds, the method is as follows: The BODIPY core structure derivative was dissolved and mixed with di(2-pyridinemethyl)amine (abbreviation: DPA) at a molar ratio of 1:1.3 to 1.5 in an anhydrous reaction medium. Anhydrous potassium carbonate was added to the mixture and the mixture was refluxed at 75℃ to 90℃ for 6 to 10 h. The reaction product was filtered, concentrated and purified to obtain a red solid BODIPY-DPA ligand compound. During the synthesis of BODIPY-DPA ligand compounds, the molar ratio of DPA to the BODIPY core must be strictly controlled between 1.3:1 and 1.5:1. Insufficient DPA (<1.2 equivalents) will lead to incomplete nucleophilic substitution, resulting in unsubstituted chloro-BODIPY intermediates in the product. Although these intermediates exhibit fluorescence, they cannot complex copper ions. This "impurity fluorescence" will create extremely high background noise, causing the probe to luminesce even in the absence of H2S, thus significantly reducing the probe's signal-to-noise ratio.

[0010] In addition, the reaction temperature must be strictly maintained at around 80°C under reflux. Because the chlorine atoms on the pyrrole ring are sterically hindered and less reactive than conventional halogenated hydrocarbons, the reaction will stop if the temperature is below 75°C, while it may cause the BODIPY skeleton to defluorinate and decompose if the temperature is above 90°C.

[0011] (3) Cu 2+- The preparation method of the BODIPY complex probe is as follows: After dissolving the BODIPY-DPA ligand compound in an organic solvent, it was reacted with copper perchlorate in the dark for 1–2 hours. The reaction solution was then precipitated, the precipitate was collected and dried to obtain a dark green solid powder, namely Cu. 2+ - Fluoroboron dipyrrole complex probe.

[0012] The nitrogen atoms on the two pyridine rings and the central amino nitrogen atom of DPA allow Cu to be drawn from three directions. 2+ Tightly fixed at the center, forming a chelate ring. This multi-point coordination creates two stable five-membered ring structures, making the resulting complex exceptionally stable. The copper ion, as the structural core, is chelated by the DPA ligand, existing as a stable complexed cation, with its charge balanced by perchlorate ions.

[0013] The Cu obtained by the above method in this invention 2+ A fluorinated boron dipyrrole (FBP) probe successfully introduced chlorine atoms into the pyrrole ring position of its BODIPY core, as well as nitrogen atoms on the two pyridine rings of DPA and a central amino nitrogen atom, thereby introducing Cu from three directions. 2+ The tightly fixed chelate ring structure at the center helps improve the stability of the probe in the SF6 decomposition product environment, while achieving a higher signal-to-noise ratio and a lower detection limit.

[0014] Preferably, the molar ratio of 4-chloro-2-benzoyl-1H-pyrrole to phosphorus oxychloride is 1:1.5 to 2.5; the molar ratio of 4-chloro-2-benzoyl-1H-pyrrole to 2,4-dimethyl-1H-pyrrole is 1:1 to 1.5; and the molar ratio of BODIPY-DPA ligand compound to copper perchlorate is 1:1 to 2.

[0015] Preferably, the reaction time of 4-chloro-2-benzoyl-1H-pyrrole with phosphorus oxychloride in step (1) is 30 to 60 minutes. Too short a reaction time will lead to incomplete acylation, while too long a reaction time may lead to excessive polymerization of the pyrrole ring, generating non-fluorescent black tar-like impurities, which will seriously interfere with the subsequent optical signal baseline and hinder the smooth progress of the subsequent reaction.

[0016] Preferably, 4-chloro-2-benzoyl-1H-pyrrole is prepared by the following method: N-benzoylmorpholine and phosphorus oxychloride were reacted under an inert atmosphere and an ice bath for 5-6 hours. Pyrrole was then added to the reaction system and the reaction was continued for 1-2 hours. The reaction solution was subjected to fluorescence quenching, organic solvent extraction, drying, and rotary evaporation to obtain the intermediate 2-benzoylpyrrole. The intermediate 2-benzoylpyrrole was redissolved in an anhydrous reaction medium and reacted with N-chlorosuccinimide until the starting material spot disappeared under TLC monitoring. The reaction solution was extracted with an organic solvent, concentrated, dried and purified to obtain a white to pale yellow solid compound, namely 4-chloro-2-benzoyl-1H-pyrrole.

[0017] Preferably, the molar ratio of N-benzoylmorpholine, phosphorus oxychloride, and pyrrole is 1:1 to 1.5:0.5 to 1; and the molar ratio of 2-benzoylpyrrole to N-chlorosuccinimide is 1:1 to 1.2.

[0018] Preferably, the anhydrous reaction medium is anhydrous dichloromethane, anhydrous acetonitrile, or anhydrous tetrahydrofuran.

[0019] The Vilsmeier-Haack reaction is extremely sensitive to moisture. When the water content in the reaction medium exceeds 0.05 wt%, POCl3 will hydrolyze to produce phosphoric acid, which not only reduces the reaction yield but also leads to an increase in byproducts, resulting in a decrease in the fluorescence quantum yield of the final synthesized BODIPY nucleus.

[0020] Preferably, the chemical structure of the BODIPY core structure derivative is as follows: ; The chemical structure of the BODIPY-DPA ligand compound is as follows: ; Thirdly, the present invention provides the above-mentioned Cu 2+ - Application of fluoroboron dipyrrole complex probe in online detection system of H2S partial discharge decomposition products in GIS.

[0021] Fourthly, the present invention provides an online detection system for H2S partial discharge decomposition products of GIS with built-in fluorescent probes. The H2S online detection system includes an internal GIS system, an external GIS system, and optical fibers connecting the internal GIS system and the external GIS system, as well as optical fiber through-wall sleeves. The GIS internal system includes a fluorescence sensing probe fixedly connected to a fiber optic wall bushing. The fluorescence sensing probe is covered with a sensitive film containing Cu. 2+ - Fluoroboron dipyrrole complex probe; The external system of GIS includes a light source control unit, a spectral detection unit, a data processing system, and an alarm system, which are connected to the fluorescence sensing probe via optical fiber. The light source control unit emits excitation light from the light source, which is transmitted to the fluorescence sensing probe via optical fiber. The spectral detection unit acquires the fluorescence signal generated by the fluorescence sensing probe under the excitation light, and performs spectral dispersion and photoelectric conversion on the fluorescence signal to generate spectral data containing wavelength and fluorescence intensity. The data processing system acquires the spectral data and calculates the H2S gas concentration value in the GIS gas chamber in real time. When the data processing system detects that the H2S gas concentration value is higher than the set warning threshold, the data processing system sends a trigger level to the alarm system. The alarm system receives the signal and activates the on-site audible and visual alarm and remote fault push, prompting maintenance personnel that there may be insulation defects inside the GIS equipment.

[0022] Fifthly, the present invention provides an online detection method for H2S, a partial discharge decomposition product of GIS. This online H2S detection method is based on the aforementioned online detection system for H2S, a partial discharge decomposition product of GIS with an embedded fluorescent probe. The online H2S detection method includes the following steps: S1: Start the light source control unit to make the light source emit excitation light of a specific wavelength, which is transmitted through the fiber optic wall sleeve to the inside of the GIS gas chamber and irradiates the sensitive film of the fluorescence sensor probe. S2: If H2S gas generated by partial discharge exists in the GIS gas chamber, H2S molecules diffuse to the surface of the sensitive membrane and react with Cu in the probe. 2+ A specific substitution reaction occurs to generate CuS, which releases the quenching state of the BODIPY fluorescent core in the sensitive film. The fluorescent sensing probe emits a green fluorescent signal under the action of excitation light, and its fluorescence intensity is positively correlated with the H2S gas concentration. S3: The spectral detection unit acquires the fluorescence signal and performs spectral dispersion and photoelectric conversion to generate a spectral data frame containing wavelength and intensity information; S4: The data processing system acquires spectral data frames and extracts the peak fluorescence intensity at characteristic wavelengths. I ), deducting background noise ( I 0 ), calculate the fluorescence enhancement factor, and substitute it into the preset value. Stern-Volmer The calibration equation is used to calculate the current H2S gas concentration value in real time and display it on the monitoring interface, generating a trend graph of concentration change over time. S5: When the data processing system detects that the H2S gas concentration is higher than the set warning threshold, the data processing system sends a trigger level to the alarm system. The alarm system then activates the on-site audible and visual alarm and remote fault push notification, alerting maintenance personnel that there may be insulation defects inside the GIS equipment.

[0023] Furthermore, Stern-Volmer The calibration equation is as follows: ; In the formula, IThe real-time fluorescence intensity obtained by the data processing system when H2S is present in the GIS chamber; I 0 The background fluorescence signal intensity of the probe in a quenched state when there is no H2S in the GIS gas chamber; I max For when Cu 2+ -All Cu on the fluoroboron dipyrrole complex probe 2+ The saturated fluorescence intensity after all fluorescence is captured by H2S; K is... Stern-Volmer Constants are inherent property parameters of the probe; C [] indicates the concentration of H2S gas.

[0024] In summary, the Cu prepared by this invention 2+ A fluorinated boron dipyrrole (FBP) probe successfully introduced chlorine atoms into the pyrrole ring position of its BODIPY core, as well as nitrogen atoms on the two pyridine rings of DPA and a central amino nitrogen atom, thereby introducing Cu from three directions. 2+ The tightly fixed chelate ring structure at the center helps improve the stability of the probe in the SF6 decomposition product environment, while achieving a higher signal-to-noise ratio and a lower detection limit.

[0025] In addition, the Cu of the present invention 2+ The -fluoroboron dipyrrole complex probe is a "turn-on" type. The probe itself is in a "fluorescence-off" state due to the fluorescence quenching effect of copper ions. After specifically reacting with H₂S, Cu... 2+ The H2S in the analyte is removed to form a CuS precipitate, and the probe recovers the characteristic strong green fluorescence of BODIPY, thus enabling qualitative and quantitative detection of H2S in the analyte gas. This invention utilizes Cu... 2+ - Fluoroboron dipyrrole complex probes are only effective against Cu. 2+ It forms a gaseous response of more insoluble sulfides, while other decomposition products of SF6 besides H2S, such as SO2, SOF2, SO2F2, CF4, etc., do not have this ability and therefore will not cause interference.

[0026] Furthermore, the Cu of the present invention 2+ - Fluoroboron dipyrrole complex probes are used in online detection systems for H2S, a partial discharge decomposition product of GIS. These probes are coated onto a fluorescent sensing probe within the GIS of the online detection system. When the probe specifically reacts with H2S, it undergoes a complete quenching process before recovering the characteristic strong green fluorescence of BODIPY, with the fluorescence intensity increasing hundreds or even thousands of times. This provides a clear and accurate optical signal. The signal changes resulting from this type of sensing offer extremely high signal-to-noise ratio and sensitivity feedback, theoretically enabling the detection of H2S concentrations at the ppb level. Attached Figure Description

[0027] Figure 1 Cu2+ Synthesis pathway flowchart of -fluoroboron dipyrrole complex probe; Figure 2 This is a structural diagram of an online detection system for H2S, a partial discharge decomposition product of GIS, with a built-in fluorescent probe. Detailed Implementation

[0028] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available. Example

[0029] This embodiment provides a Cu 2+ The preparation method of the -fluoroboron dipyrrole complex probe is as follows: Figure 1 As shown, it includes the following steps: (a) Synthesis of Compound 1 Ethyl acetoacetate (10.0 g, 63.2 mmol) was dissolved in glacial acetic acid (40 mL) under stirring at room temperature. A solution prepared by dissolving sodium nitrite (7.90 g, 114.6 mmol) in water (40 mL) was slowly added dropwise to this solution. After the addition was complete, the reaction was continued at room temperature for 4 hours. Subsequently, 2,4-pentanedione (7.60 mL, 75.8 mmol) and zinc powder (10.60 g, 162.1 mmol) were added sequentially to the reaction system. The reaction system was gradually heated to 60 °C and stirred at this temperature for 1 hour. After the reaction was complete, the mixture was filtered while hot to remove insoluble matter. The filtrate was diluted with ice water and extracted with dichloromethane (3 × 100 mL). The combined organic phases were dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to give an orange-red solid crude product (ethyl 3,5-dimethyl-1H-4-pyrrolecarboxylate). The crude product can be used directly in the next reaction, with a yield of approximately 12.5 g (yield of approximately 78%).

[0030] (b) Synthesis of compound 2 Compound 1 (ethyl 3,5-dimethyl-1H-4-pyrrolecarboxylate, 10.0 g, approximately 60 mmol) was dissolved in ethanol (30 mL), and an aqueous solution of sodium hydroxide (4.8 g, 120 mmol) (20 mL) was added. The mixture was heated under reflux for 2–4 hours until TLC monitoring showed complete hydrolysis of the ester groups. After the reaction was complete, the reaction solution was cooled and poured into crushed ice water. The pH was adjusted to acidic (pH ≈ 3–4) with dilute hydrochloric acid, resulting in the precipitation of a large amount of white to pale red precipitate. The precipitate was collected by suction filtration, washed with water, and dried. The dried solid was placed in a round-bottom flask, and ethylene glycol was added as a solvent. The mixture was heated to 160–180 °C under nitrogen protection for a high-temperature decarboxylation reaction until no more carbon dioxide bubbles were produced. After cooling, the reaction solution was poured into ice water and extracted with dichloromethane or diethyl ether (3 × 50 mL). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated. The crude product was purified by vacuum distillation or silica gel column chromatography to obtain compound 2 (2,4-dimethyl-1H-pyrrole), which is a colorless to light brown liquid / solid that is easily oxidized and needs to be stored at low temperature and protected from light.

[0031] (c) Synthesis of compound 3 In a dry 1000 mL round-bottom flask, morpholine (96 mL, 1.10 mol) and triethylamine (60 mL, 0.43 mol) were added, followed by 300 mL of dichloromethane (DCM). The mixture was stirred in an ice bath until homogeneous. Benzoyl chloride (84 mL, 0.73 mol) was slowly added dropwise to the system using a constant-pressure dropping funnel, controlling the dropping rate to maintain the system temperature below 20 °C. After the addition was complete, the mixture was brought to room temperature and stirred overnight (approximately 12 hours). After the reaction was complete, the reaction solution was washed with deionized water (3 × 200 mL). The mixture was separated, and the organic phase was dried over anhydrous sodium sulfate. The solution was filtered, and the solvent was removed by rotary evaporation under reduced pressure to obtain a white solid crude product. The crude product was recrystallized from a small amount of cold ethanol to obtain compound 3 (N-benzoylmorpholine) of high purity, with a yield of approximately 105 g (yield approximately 85%).

[0032] (d) Synthesis of compound 4 Compound 3 (47.6 g, 0.25 mol) was mixed with phosphorus oxychloride (POCl3, 25 mL, 0.27 mol) in a 250 mL round-bottom flask under ice bath and nitrogen protection. The mixture was stirred at room temperature until completely dissolved and the reaction was continued for 5.5 hours. Subsequently, pyrrole (11.05 g, 0.16 mol) was slowly added dropwise to the reaction system, and the reaction was continued at room temperature for 1 hour after the addition was complete. After the reaction was completed, the reaction system was placed in an ice bath, and excess saturated sodium carbonate aqueous solution was slowly added dropwise to quench the reaction until no more bubbles were released. The mixture was extracted with dichloromethane (3 × 100 mL), and the organic phases were combined and dried over anhydrous sodium sulfate. The mixture was filtered, and the solvent was removed by rotary evaporation to give approximately 21.5 g (approximately 125.6 mmol) of crude 2-benzoylpyrrole intermediate. The intermediate was redissolved in 150 mL of anhydrous tetrahydrofuran (THF) under ice bath conditions, and N-chlorosuccinimide (17.6 g, 131.8 mmol) was slowly added in portions. After the addition was complete, the mixture was allowed to rise to room temperature and stirred for 4 hours (TLC monitoring until the starting material spot disappeared). After the reaction was complete, water (100 mL) was added to quench the reaction, and the mixture was extracted with ethyl acetate (3 × 80 mL). The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 2:1) to give compound 4 (4-chloro-2-benzoyl-1H-pyrrole), a white to pale yellow solid, with a yield of approximately 15.4 g (overall yield of approximately 47%).

[0033] (e) Synthesis of compound 5 In a dry Schlenk reaction tube, compound 4 (2.00 g, 8.50 mmol, 4-chloro-2-benzoyl-1H-pyrrole) and 30 mL of anhydrous dichloromethane (DCM) were added and stirred under ice bath and inert gas protection. Phosphorus oxychloride (POCl3, 1.60 mL, 17.0 mmol) was slowly added dropwise. After the addition was complete, the mixture was moved to room temperature and stirred for 30 minutes. The solution should become clear at this point, indicating that the Vilsmeier-Haack active intermediate has been formed. It is worth noting that the Vilsmeier-Haack reaction is extremely sensitive to moisture. If the water content of the solvent DCM exceeds 0.05%, POCl3 will hydrolyze to form phosphoric acid, which will not only reduce the reaction yield but also lead to an increase in byproducts, resulting in a decrease in the fluorescence quantum yield of the final synthesized BODIPY core (compound 5). In addition, the activation time after adding POCl3 must be strictly controlled between 30 minutes and 1 hour. Too short a time will result in incomplete acylation, while too long a time may lead to excessive polymerization of the pyrrole ring, generating non-fluorescent black tar-like impurities that seriously interfere with the subsequent optical signal baseline.

[0034] Subsequently, a solution of compound 2 (2,4-dimethyl-1H-pyrrole, 0.97 g, 10.2 mmol) dissolved in 10 mL of anhydrous DCM was slowly added dropwise to the reaction system through a constant-pressure dropping funnel. After the addition was complete, the reaction was stirred for 3–4 hours at room temperature in the dark. Under nitrogen protection, the reaction system was placed back in an ice bath, and triethylamine (6.0 mL, 43.0 mmol) was slowly added dropwise with stirring for 15 minutes to deprotonate it. Then, boron trifluoride diethyl ether complex (BF3·OEt2, 6.5 mL, 52.0 mmol) was added very slowly. After the addition was complete, the ice bath was removed, and the system was heated to room temperature (or gently refluxed at 40 °C) and the reaction was stirred for 1–2 hours until TLC monitoring showed complete formation of a strongly fluorescent product.

[0035] After the reaction was complete, the reaction system was placed back in an ice bath, and saturated sodium carbonate (Na₂CO₃) aqueous solution was slowly added dropwise to quench the reaction until no more bubbles were generated. The mixture was separated, and the aqueous phase was extracted with dichloromethane (3 × 20 mL). The organic phases were combined, dried over anhydrous sodium sulfate (Na₂SO₄), filtered, and the filtrate was concentrated by rotary evaporation under reduced pressure to obtain a dark oily or solid crude product.

[0036] The crude product was separated and purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 2:1, v / v). The main red band was collected, and the solvent was removed by rotary evaporation to obtain a metallic orange-red solid compound 5 (a derivative of the BODIPY parent structure) with a yield of approximately 1.65 g (75% yield).

[0037] In this process, the electrophile (compound 4) is first activated by phosphorus oxychloride (POCl3), while the nucleophile (compound 2) undergoes condensation, initially constructing a dipyrrolemethane skeleton. Subsequently, triethylamine is added as an acid-binding agent to assist in the deprotonation of the pyrrole nitrogen atoms, allowing the two nitrogen atoms to tightly "clamp" the boron atoms from the subsequently added boron trifluoride, completing the fluorine-boron complexation reaction. This step locks the originally flexible dipyrrole skeleton into a rigid, coplanar tricyclic structure, endowing the molecule with excellent fluorescence properties.

[0038] (f) Synthesis of compound 6 Compound 5 (1.50 g, 3.95 mmol) and di(2-pyridinemethyl)amine (DPA, 1.15 g, 5.14 mmol) were placed in a round-bottom flask and dissolved in 30 mL of anhydrous acetonitrile (CH3CN). Under nitrogen protection, anhydrous potassium carbonate (K2CO3, 1.64 g, 11.85 mmol) was added, and the reaction mixture was heated to 80 °C and refluxed for 8 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered to remove inorganic salts, and the filtrate was concentrated by rotary evaporation. The crude product was purified by silica gel column chromatography (eluent: dichloromethane / methanol = 20:1), and the main red band was collected and concentrated to give the target BODIPY-DPA ligand compound 6 (1.72 g, 82% yield) as a red solid.

[0039] It is important to note that the molar ratio of the starting material DPA to compound 5 needs to be controlled between 1.3:1 and 1.5:1. Insufficient DPA (<1.2 equivalents) will lead to incomplete nucleophilic substitution, resulting in unsubstituted chloro-BODIPY intermediates in the product. While these intermediates exhibit fluorescence, they cannot complex copper ions. This "impurity fluorescence" will create extremely high background noise, causing the probe to emit light even in the absence of H2S, thus significantly reducing the probe's signal-to-noise ratio.

[0040] In addition, the reaction temperature must be strictly maintained at 80°C under reflux. Due to the large steric hindrance of the chlorine atom on the pyrrole ring and its lower reactivity than conventional haloalkanes, the reaction will stop below 75°C; while above 90°C, it may cause the BODIPY skeleton to defluorinate and decompose.

[0041] (g) Synthesis of Compound 7 Compound 6 (1.00 g, 1.88 mmol) was dissolved in 20 mL of methanol and stirred at room temperature until completely dissolved. A methanol solution (10 mL) of copper perchlorate (Cu(ClO4)2·6H2O, 0.70 g, 1.88 mmol) was slowly added dropwise to this solution. After the addition was complete, the mixture was stirred for 1 hour at room temperature in the dark. After the reaction was complete, the reaction solution was poured into 50 mL of ice-cold diethyl ether, and a large amount of precipitate formed. The precipitate was filtered, washed three times with cold diethyl ether, and the solid product was collected. Finally, after vacuum drying, the target probe compound 7 (Cu(ClO4)2·6H2O, 0.70 g, 1.88 mmol) was obtained as a dark green solid powder. 2+ -BODIPY complex probe (1.15g, yield 92%).

[0042] The nitrogen atoms on the two pyridine rings of DPA and the central amino nitrogen atom tightly anchor the Cu²⁺ ion at the center from three directions, forming a chelate ring. This multi-site coordination creates two stable five-membered ring structures, making the resulting complex exceptionally stable. The copper ion, as the structural core, is chelated by the DPA ligand and exists as a stable complexed cation, with its charge balanced by perchlorate ions.

[0043] Compared to existing technologies (CN103013496B), this invention retains a strong electron-withdrawing group—a chlorine atom (—Cl)—at the pyrrole ring position of the BODIPY core. The introduction of this chlorine atom effectively reduces the electron cloud density of the BODIPY core through an electron-withdrawing inductive effect, thereby significantly improving its chemical stability and making it less susceptible to degradation in the SF6 decomposition product environment, resulting in a longer probe lifespan. This makes Cu… 2+ After being captured by H2S, BODIPY's fluorescence recovery is more thorough and rapid, which helps to achieve a higher signal-to-noise ratio and a lower detection limit.

[0044] The Cu prepared in this embodiment 2+ The -fluorinated boron dipyrrole (BBOPY-DPA) complex probe is formed by the complexation of a BODIPY-DPA ligand with divalent copper ions. The probe itself is in a "fluorescence-off" state due to the fluorescence quenching effect of copper ions. Upon specific reaction with H₂S, Cu²⁺ is removed, forming a CuS precipitate, and the probe regains the characteristic strong green fluorescence of BODIPY, thus enabling qualitative and quantitative detection of H₂S in the analyte gas. The probe only reacts with Cu²⁺ ions that can bind Cu²⁺. 2+ It forms a gaseous response of more insoluble sulfides, while other decomposition products of SF6 besides H2S, such as SO2, SOF2, SO2F2, CF4, etc., do not have this ability and therefore will not cause interference.

[0045] Because it is a "turn-on" type sensor, the fluorescence intensity can increase hundreds or even thousands of times from complete quenching to complete luminescence, providing a clear and unambiguous optical signal. The signal change brought about by this type of sensor provides extremely high signal-to-noise ratio and sensitivity feedback, and theoretically can detect H2S concentrations at the ppb level. Example

[0046] This embodiment provides an online detection system for H2S partial discharge decomposition products of GIS with a built-in fluorescent probe. The purpose is to safely and stably place the miniature fluorescent sensing probe inside the GIS gas chamber and fully expose it to the SF6 gas environment to achieve effective sensing of H2S gas.

[0047] The detection system in this embodiment is as follows: Figure 2 As shown, the system comprises an external GIS system, an internal GIS system, optical fibers connecting the internal and external systems, and fiber optic wall bushings. The internal GIS system includes a fluorescent sensing probe fixedly connected to the fiber optic wall bushing. The fluorescent sensing probe is preferably installed in a non-critical electric field region of the basin-type insulator. This region itself has structural fixing and connection functions, and its surface or edges are suitable for the arrangement of the sensing head. The Cu prepared in Example 1... 2+The fluorine-boron dipyrrole complex probe was dissolved in an appropriate amount of tetrahydrofuran, and PVC was added as a film-forming aid to enhance mechanical strength. It was then uniformly coated onto the pretreated end face of a special optical fiber or the surface of a decladding optical fiber core using a spin-coating method. After solvent evaporation, Cu... 2+ - The fluoroboron dipyrrole complex probe forms a solid sensitive film on the fluorescent sensing probe of the optical fiber. For fiber fixation, a micro-scaffold is prepared using materials with excellent insulation properties and resistance to corrosion by SF6 decomposition products, such as polytetrafluoroethylene or alumina ceramic. The fiber end coated with the sensitive film is embedded and fixed inside the micro-scaffold, ensuring sufficient contact with the gas while providing mechanical protection to avoid direct exposure to high-velocity gas or solid particles.

[0048] The fiber optic wall bushing uses a metal flange as its core structure, incorporates a precision fiber optic interface, and employs multi-level sealing technology to ensure absolute airtightness. Its creepage distance and insulation strength must match the GIS enclosure rating to withstand operating voltage and lightning surge voltage. Standard interfaces can be pre-installed on the GIS enclosure, or during power outage maintenance, professional personnel can drill holes in the enclosure and secure the fiber optic wall bushing using welding or bolts. The internal GIS system uses special optical fiber with a corrosion-resistant sheath, extending from the sensing probe to the interface inside the bushing. Externally, it connects to the optical signal processing unit of the external GIS system via the outer interface, thereby enabling real-time detection and signal output of H2S concentration.

[0049] The GIS external system mainly consists of an integrated optical signal processing chassis and supporting terminals, according to Figure 2 The hardware connection logic shown is specifically divided into the following four functional modules: Light source control unit: This unit integrates a high-stability LED or laser diode of a specific wavelength as the excitation source. Its output is connected to the input arm of a fiber optic coupler via a fiber optic connector to deliver excitation light energy into the GIS. This unit receives instructions from the data processing system and can adjust the switching on / off state and output power of the light source.

[0050] Spectroscopic Detection Unit: The core of this unit is a miniature high-sensitivity spectrometer. Its optical input is connected to the output arm of the reflector bracket via optical fiber, used to receive fluorescence signals containing H2S concentration information returned by probes inside the GIS. Its data output is connected to the data processing system via a high-speed data cable, converting the acquired optical signals into digital electrical signals.

[0051] Data Processing System: This system is typically an industrial control computer or embedded processing terminal equipped with dedicated analysis software. It connects to the light source control unit and the spectral detection unit via data cables. It is responsible for synchronously controlling the excitation pulses of the light source and receiving spectral data in real time. The system internally runs a fluorescence intensity-concentration inversion algorithm and a calibration curve database, responsible for converting digital signals into visualized H2S concentration values.

[0052] Alarm System: This system connects to the I / O interface or communication port of the data processing system. When the H2S concentration calculated by the data processing system exceeds the preset safety threshold, the system immediately triggers an audible and visual alarm signal and uploads the alarm information to the substation remote monitoring center via the Ethernet interface.

[0053] Based on the real-time H2S concentration detection method and steps of this system, combined with the above hardware structure and the probe characteristics prepared in Example 1, the real-time detection process of H2S gas inside GIS by this system is as follows: Step one: The excitation light transmission data processing system sends a command to activate the light source control unit, and the light source emits excitation light of a specific wavelength. The excitation light is transmitted via optical fiber to the fiber optic wall sleeve, and then enters the GIS gas chamber along the optical fiber, finally illuminating the Cu-coated surface. 2+ - Fluoroboron dipyrrole complexed probe on the sensitive membrane of a fluorescent sensing probe.

[0054] Step 2, Gas Sensing Reaction and Fluorescence Recovery: If H2S gas generated by partial discharge is present in the GIS gas chamber, H2S molecules will diffuse to the surface of the sensitive membrane and react with Cu in the probe. 2+ A specific substitution reaction occurs, generating CuS. This reaction removes the quenching state of the BODIPY fluorescent core, and the probe immediately emits a strong green fluorescent signal under excitation light, with the fluorescence intensity being positively correlated with the H2S gas concentration.

[0055] Step 3, Signal Acquisition and Photoelectric Conversion: The fluorescence signal generated by the probe is collected by the same optical fiber and returns along the original optical path. After optical path separation by the fiber optic beam splitter outside the GIS, the fluorescence signal enters the spectral detection unit. The spectrometer splits and converts the received optical signal into photoelectric data, generating a spectral data frame containing wavelength and intensity information.

[0056] Step 4, Data Analysis and Concentration Inversion: The data processing system reads the spectral data and extracts the peak fluorescence intensity at characteristic wavelengths. The system automatically subtracts background noise, calculates the fluorescence enhancement factor, and substitutes it into the preset values. Stern- Volmer The calibration equation is used to calculate the current H2S gas concentration in real time.

[0057] Step 5, Status Monitoring and Alarm System: The calculated concentration values ​​are displayed in real time on the monitoring interface, and a trend graph of concentration changes over time is generated. Once the monitored value continues to exceed the set warning threshold, the data processing system immediately sends a trigger level to the alarm system, activating on-site audible and visual alarms and remote fault push notifications, alerting maintenance personnel that there may be insulation defects inside the GIS equipment.

[0058] Compared to existing technologies (CN116879688A) that rely on macroscopic physical optical signal detection of non-specific partial discharge, where the sensing part is mainly a linear or planar distribution scheme and the sensor itself is directly exposed inside the cavity, this invention explicitly proposes the concept of a miniature sensing probe. It is fixed to the grounding mounting bolt of the basin-type insulator via a customized L-shaped or ring-shaped insulating bracket, cleverly utilizing the "electric field dead zone" at the edge of the basin-type insulator, thereby avoiding the local electric field concentration effect caused by sensor implantation. In the internal structure of the GIS in this embodiment, it is positioned in the concave shielding area of ​​the basin-type insulator near the grounding metal shell of the GIS. This area is geometrically far from the central high-voltage conductor, thus ensuring its insulation performance, mechanical strength, and corrosion resistance in the SF6 gas environment in this non-critical electric field region. Furthermore, multi-stage sealing technology ensures absolute airtightness, fully considering the high-voltage operating conditions of the GIS equipment. Example

[0059] This embodiment provides a method for quantitatively detecting the concentration of H2S, a decomposition product of partial discharge in GIS, using the detection system of Embodiment 2, thereby determining the severity of partial discharge in GIS. The detection method includes the following steps: Based on the “Turn-On” type Cu prepared in Example 1 2+ The BODIPY probe is used to quantitatively analyze H2S concentration by fluorescence recovery intensity. A calibration curve is established to convert the measured fluorescence intensity into the concentration of the target gas. After the probe molecule absorbs the energy of the excitation light, it transitions from the ground state to the excited state. The spectrometer or photodetector receives these fluorescence signals and converts them into digital electrical signals. The intensity of this signal is the fluorescence intensity we want to measure.

[0060] For the fluorescence recovery (“Turn-On”) process, the change in fluorescence signal is normalized to eliminate the influence of baseline drift, and its quantitative relationship can usually be described by a modified equation: ; in: I represents the real-time fluorescence intensity, which is the fluorescence intensity measured in the presence of H2S; This represents the initial fluorescence intensity, i.e., the background fluorescence signal when the probe is in a quenched state without H2S. This represents the maximum fluorescence intensity, which is the saturated fluorescence intensity after all Cu²⁺ on the probes has been removed by H₂S. express Stern-Volmer The constant (or binding constant) is a property parameter of the probe itself, representing the probe's sensitivity and binding ability to H2S; This indicates the concentration of hydrogen sulfide.

[0061] This invention utilizes a "fluorescence-on" type chemical sensing mechanism to achieve highly selective and sensitive quantitative detection of hydrogen sulfide (H2S). The core of this invention lies in the construction of a Cu²⁺-fluoroboron dipyrrole (Cu²⁺-BODIPY) complex probe. This probe covalently links a strong chelating unit of di(2-pyridinemethyl)amine (DPA) to the fluorescent signal group BODIPY through ligand design. Initially, the chelated Cu²⁺ in the probe acts as a highly efficient fluorescence quencher, inducing a "fluorescence-off" state through photoinduced electron transfer or energy transfer effects, resulting in extremely weak fluorescence intensity. When the probe comes into contact with H2S molecules, the formation of a CuS precipitate with a lower solubility product triggers a specific and irreversible metal ion substitution reaction, causing Cu²⁺ to be removed from the probe's coordination center. This process relieves the quenching effect on the BODIPY fluorophore, driving a significant "fluorescence-on" effect and restoring and releasing strong green fluorescence. There is a clear quantitative relationship between the recovered fluorescence intensity and the H2S concentration, which can be corrected by... Stern-Volmer The equation describes the relationship. In the low concentration range, this ratio exhibits a good linear relationship with the gas concentration. This allows the data processing system to directly convert the acquired light signal into a concentration reading using a simple linear fitting algorithm, greatly reducing the computational complexity of the online monitoring system and improving response speed. By pre-establishing fluorescence intensity-concentration calibration curves using standard gases of different concentrations, the fluorescence signal obtained from real-time monitoring can be directly inverted into the accurate concentration value of H2S in the GIS gas chamber, thereby achieving early warning and severity assessment of insulation faults.

[0062] After deriving the formula, quantitative analysis was performed in a laboratory environment to verify it.

[0063] Step 1: Build a calibration system to simulate the GIS environment. A sealed gas chamber can precisely control the temperature, pressure, background gas (high-purity SF6 or N2), and the concentration of trace amounts of H2S.

[0064] Step 2: Fabrication of a standard sensing unit. A Cu²⁺-BODIPY probe is fixed in thin film to the same fiber optic end cap used in future GIS applications.

[0065] Step 3: Data Collection. Introduce a known concentration of H2S / SF6 mixed gas into the gas chamber in increments of 5 ppm until reaching 100 ppm. At each concentration point, after the system stabilizes, measure and record the stable fluorescence intensity value using a fluorescence detection system, while simultaneously recording the fluorescence intensity under pure SF6.

[0066] Step 4: Plot the calibration curve. Plot a scatter plot with H2S concentration on the x-axis and the measured fluorescence intensity (or the change in fluorescence intensity) on the y-axis.

[0067] By performing linear or nonlinear fitting on these data points, a calibration curve and the corresponding mathematical formula are obtained.

[0068] Step 5: On-site Measurement and Concentration Inversion. At the GIS site, the sensing system continuously measures and outputs fluorescence intensity signals as the measured values. Substituting these values ​​into the previously obtained calibration curve formula, the real-time H2S concentration in the GIS gas chamber can be directly calculated. To improve accuracy, the system software performs signal averaging, filtering, and removes background interference from ambient light and electronic noise.

Claims

1. A Cu 2+ - a boron difluoride porphyrin complex probe characterized by, The Cu 2+ The Cu 2+ The chemical structure of the BODIPY-DPA complex probe is as follows: 。 2. A Cu of claim 1 2+ - Process for the preparation of a fluoroboron dipyrrin complex probe, characterized in that, Includes the following steps: (1) Preparation of chlorinated BODIPY, the method is as follows: 4-Chloro-2-benzoyl-1H-pyrrole was reacted with phosphorus oxychloride in an anhydrous reaction medium at low temperature and under an inert atmosphere to synthesize the Vilsmeier-Haack active intermediate. 2,4-Dimethyl-1H-pyrrole, triethylamine, and boron trifluoride diethyl ether were added sequentially to the Vilsmeier-Haack active intermediate and the reaction proceeded until TLC monitoring showed complete formation of a strongly fluorescent product. The reaction product was subjected to fluorescence quenching, crude extraction, and purification to obtain a metallic orange-red solid compound, namely chloroBODIPY. (2) Preparation of BODIPY-DPA ligand compounds, the method is as follows: The chloroBODIPY and di(2-pyridinemethyl)amine were dissolved and mixed in an anhydrous reaction medium at a molar ratio of 1:1.3-1.

5. Anhydrous potassium carbonate was added to the mixture and the mixture was refluxed at 75℃-90℃ for 6-10 h. The reaction product was filtered, concentrated and purified to obtain a red solid BODIPY-DPA ligand compound. (3) Cu 2+ BODIPY complex probe preparation, as follows: After the BODIPY-DPA ligand compound is dissolved in an organic solvent and reacted with copper perchlorate in the dark for 1-2 hours, the reaction solution is precipitated, the precipitate is collected and dried to obtain a dark green solid powder, i.e. Cu 2+ - boron-dipyrromethene complex probes.

3. Cu as described in claim 2 2+ The method for preparing a fluoroboron dipyrrole complex probe is characterized by, The molar ratio of 4-chloro-2-benzoyl-1H-pyrrole to phosphorus oxychloride is 1:1.5 to 2.5; the molar ratio of 4-chloro-2-benzoyl-1H-pyrrole to 2,4-dimethyl-1H-pyrrole is 1:1 to 1.5; and the molar ratio of the BODIPY-DPA ligand compound to copper perchlorate is 1:1 to 2.

4. Cu as described in claim 2 2+ The method for preparing a fluoroboron dipyrrole complex probe is characterized by, The 4-chloro-2-benzoyl-1H-pyrrole was prepared by the following method: N-benzoylmorpholine and phosphorus oxychloride were reacted under an inert atmosphere and an ice bath for 5-6 hours. Pyrrole was then added to the reaction system and the reaction was continued for 1-2 hours. The reaction solution was subjected to fluorescence quenching, organic solvent extraction, drying, and rotary evaporation to obtain the intermediate 2-benzoylpyrrole. The intermediate 2-benzoylpyrrole was redissolved in an anhydrous reaction medium and reacted with N-chlorosuccinimide until the starting material spot disappeared under TLC monitoring. The reaction solution was extracted with an organic solvent, concentrated, dried and purified to obtain a white to pale yellow solid compound, namely 4-chloro-2-benzoyl-1H-pyrrole.

5. The Cu as described in claim 4 2+ The method for preparing a fluoroboron dipyrrole complex probe is characterized by, The molar ratio of N-benzoylmorpholine, phosphorus oxychloride, and pyrrole is 1:1 to 1.5:0.5 to 1; the molar ratio of 2-benzoylpyrrole to N-chlorosuccinimide is 1:1 to 1.

2.

6. Cu as described in claim 2 2+ The method for preparing a fluoroboron dipyrrole complex probe is characterized by, The chemical structure of the BODIPY core structure derivative is as follows: ; The chemical structure of the BODIPY-DPA ligand compound is as follows: .

7. The Cu of claim 1 2+ Application of fluorobodipyridyl complex probe in GIS partial discharge decomposition product H2S on-line detection system.

8. An online detection system for H2S, a partial discharge decomposition product of GIS with an embedded fluorescent probe, characterized in that, The H2S online detection system includes an internal GIS system, an external GIS system, and optical fibers connecting the internal GIS system and the external GIS system, as well as optical fiber wall sleeves. The GIS internal system comprises a fluorescent sensing probe fixedly connected with an optical fiber wall bushing, a sensitive film is coated on the fluorescent sensing probe, and the sensitive film contains the Cu 2+ fluoroborondipyrromethene complex probes; The external system of the GIS includes a light source control unit, a spectral detection unit, a data processing system, and an alarm system that are connected to the fluorescence sensing probe via optical fiber. The light source control unit emits excitation light from the light source, which is transmitted to the fluorescence sensing probe via optical fiber. The spectral detection unit acquires the fluorescence signal generated by the fluorescence sensing probe under the excitation light and performs spectral dispersion and photoelectric conversion on the fluorescence signal to generate spectral data containing wavelength and fluorescence intensity. The data processing system acquires the spectral data and calculates the H2S gas concentration value in the GIS gas chamber in real time. When the data processing system detects that the H2S gas concentration value is higher than the set warning threshold, the data processing system sends a trigger level to the alarm system. The alarm system receives the signal and activates the on-site audible and visual alarm and remote fault push, prompting maintenance personnel that there may be insulation defects inside the GIS equipment.

9. A method for online detection of H2S, a partial discharge decomposition product of GIS, characterized in that, The H2S online detection method is based on the GIS partial discharge decomposition product H2S online detection system with built-in fluorescent probe as described in claim 8; the H2S online detection method includes the following steps: S1: start the light source control unit to make the light source emit excitation light of a specific wavelength, and transmit it through the optical fiber through the optical fiber wall sleeve to the inside of the GIS gas chamber, irradiating the sensitive film of the fluorescent sensing probe. S2: If H2S gas generated by partial discharge exists in the GIS gas chamber, H2S molecules diffuse to the surface of the sensitive film and react with Cu in the probe 2+ CuS is generated by specific replacement reaction, which releases the quenching state of the BODIPY fluorescent mother nucleus in the sensitive film, and the fluorescent sensing probe emits green fluorescent signal under the action of excitation light, and the fluorescence intensity is positively correlated with the concentration of H2S gas; S3: The spectral detection unit acquires the fluorescence signal and performs spectral dispersion and photoelectric conversion to generate a spectral data frame containing wavelength and intensity information; S4: The data processing system acquires spectral data frames and extracts the peak fluorescence intensity at characteristic wavelengths. I ), deducting background noise ( I 0 ), calculate the fluorescence enhancement factor, and substitute it into the preset value. Stern-Volmer The calibration equation is used to calculate the current H2S gas concentration value in real time and display it on the monitoring interface, generating a trend graph of concentration change over time. S5: When the data processing system detects that the H2S gas concentration is higher than the set warning threshold, the data processing system sends a trigger level to the alarm system. The alarm system then activates the on-site audible and visual alarm and remote fault push notification, alerting maintenance personnel that there may be insulation defects inside the GIS equipment.

10. The online detection method for H2S decomposition products of GIS partial discharge as described in claim 9, characterized in that, The Stern-Volmer The calibration equation is as follows: In the formula, I The real-time fluorescence intensity obtained by the data processing system when H2S is present in the GIS chamber; I 0 The background fluorescence signal intensity of the probe in a quenched state when there is no H2S in the GIS gas chamber; I max For when Cu 2+ -All Cu on the fluoroboron dipyrrole complex probe 2+ The saturated fluorescence intensity after all fluorescence is captured by H2S; K is Stern-Volmer Constants are intrinsic property parameters of the probe; C [] indicates the concentration of H2S gas.

Images