Detection algorithm for trace SF6 gas in closed space

Abstract

The invention discloses a detection algorithm for trace SF6 gas in a closed space, and the method comprises the steps: arranging a high-sensitivity sensor in a closed space environment, collecting a square wave signal generated by SF6 gas leakage, and carrying out the preprocessing of the collected waveform signal; based on waveform characteristics generated by SF6 leakage ions, converting the square wave signal into a sinusoidal waveform, and extracting gas spectrum and photoacoustic signal characteristics through waveform analysis; according to a gas spectrum and photoacoustic signal characteristics, establishing a corresponding graphic pattern, and combining a waveform conversion result to construct a sensing waveform; gas ions in the closed space are migrated into a gas analyzer for separation through an electric transmission method; accurate detection of the concentration of trace SF6 gas in the gas analyzer is realized through a differential energy detection (DED) algorithm; and outputting an SF6 gas detection report according to a processing result of the DED algorithm. According to the method, the detection time can be shortened, the detection efficiency is improved, and a more accurate detection result is provided for a user.

Description

Technical Field

[0001] The present invention relates to the field of gas detection technology, and in particular to a detection algorithm for trace SF6 gas in a confined space. Background Art

[0002] Sulfur hexafluoride (SF6) gas has been widely used in the power industry due to its excellent electrical properties and chemical stability, especially as an insulating and arc-extinguishing medium in high-voltage electrical equipment. SF6 gas has high dielectric strength, good arc-extinguishing performance and low thermal conductivity, making it an ideal choice for power equipment such as transformers, circuit breakers, and gas-insulated switches. However, after SF6 gas leaks into the atmosphere, its stable chemical structure is difficult to be naturally decomposed, which will lead to a gradual increase in the concentration of SF6 in the atmosphere. Although the concentration of SF6 in the atmosphere is relatively low, its strong greenhouse effect cannot be ignored and has a potential impact on global warming. Therefore, strict control and monitoring of SF6 gas leakage is crucial for environmental protection and the sustainable development of the power industry.

[0003] At present, although many methods have been proposed and applied for the detection technology of SF6 gas in confined spaces, there are still some limitations. Traditional detection methods, such as electrochemical sensor method, infrared spectroscopy, etc., can realize the detection of SF6 gas, but they are insufficient in detection sensitivity, response speed and cost. Although the electrochemical sensor method has a low cost, it is easily affected by environmental factors such as temperature and humidity, resulting in a decrease in the accuracy of the detection results. The infrared spectroscopy method requires expensive equipment and complex operations and is not suitable for all scenarios. In addition, these traditional methods can often only achieve qualitative or semi-quantitative detection, and it is difficult to accurately measure trace SF6 gas.

[0004] With the development of the power industry and the improvement of environmental protection requirements, the requirements for SF6 gas leakage detection technology are becoming higher and higher. On the one hand, it is necessary to improve the sensitivity and accuracy of detection to achieve accurate measurement of trace SF6 gas; on the other hand, it is necessary to reduce the detection cost and improve the detection efficiency to meet the needs of large-scale applications and long-term monitoring. Therefore, the development of an efficient, accurate and low-cost SF6 gas detection algorithm has become a hot topic in current research. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of high detection cost, long detection time, insufficient detection sensitivity and accuracy in the prior art and to propose a detection algorithm for trace SF6 gas in a confined space.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: a detection algorithm for trace SF6 gas in a confined space, comprising the following steps:

[0007] Step S1, arranging a high-sensitivity sensor in a confined space environment, collecting a square wave signal generated by SF6 gas leakage, and preprocessing the collected waveform signal;

[0008] Step S2, based on the waveform characteristics generated by the SF6 leakage ions, convert the square wave signal into a sine waveform, and extract the gas spectrum and photoacoustic signal characteristics through waveform analysis;

[0009] Step S3, establishing a corresponding graphic style according to the gas spectrum and photoacoustic signal characteristics, and constructing a sensing waveform in combination with the waveform conversion result;

[0010] Step S4, transferring the SF6 gas ions in the enclosed space to the gas analyzer for separation by electrical transport method;

[0011] Step S5, realizing accurate detection of trace SF6 gas concentration in the gas analyzer by using a differential energy detection (DED) algorithm;

[0012] Step S6: outputting the SF6 gas detection report according to the processing result of the DED algorithm.

[0013] Furthermore, in step S1, the following sub-steps are also included:

[0014] S1-1, selecting a high-sensitivity sensor according to the characteristics of the confined space and SF6 gas, wherein the high-sensitivity sensor includes an infrared imaging sensor, a laser sensor, and an electrochemical sensor;

[0015] S1-2, start the sensor to collect the square wave signal generated by the SF6 gas leakage, and the sensor can fully cover the confined space;

[0016] S1-4, processing and analyzing the waveform signal collected by the sensor through the TMS+XD joint chip, wherein the processing includes filtering, signal amplification and reduction, and the analysis includes statistical analysis, pattern recognition, and data mining;

[0017] S1-5, filter the waveform signal, amplify and reduce the signal through the following formula:

[0018]

[0019] y(t)=A*x(t)(enlarged)

[0020] y(t)=B*x(t) (reduced, B<1)

[0021] Where y[n] is the filter output, x[n] is the filter input, h[n] is the filter coefficient, N is the filter order; y(t) is the output signal, x(t) is the input signal, A is the amplification gain factor, and B is the reduction gain factor;

[0022] S1-6, perform statistical analysis, pattern recognition, and data mining on the waveform signal using the following formula:

[0023]

[0024]

[0025] Among them, μ is the mean, x i is the i-th data point in the dataset, N is the total number of data points; w is the weight vector, b is the bias term, ξ is the slack variable, and C is the regularization parameter; J is the objective function of the algorithm, K is the number of clusters, and C k is the kth cluster, μ k is the mean of the kth cluster, x i is a data point.

[0026] Furthermore, in step S2, the following sub-steps are also included:

[0027] S2-1, identify the specific waveform characteristics of the square wave signal generated by the SF6 leakage ions on the sensor, and convert the square wave signal into a sine wave. The specific formula is:

[0028]

[0029] Where y′(t) is the sinusoidal output waveform, A is the amplitude, which indicates the maximum distance the waveform deviates from the equilibrium position, ω is the angular frequency, and φ is the phase angle, which indicates the position of the waveform at time t=0;

[0030] S2-2, performing waveform analysis on the converted sinusoidal waveform, wherein the waveform analysis includes calculating the frequency, amplitude, phase, and periodicity characteristics of the waveform. The specific formula is:

[0031]

[0032] Where f is the frequency, Δt is the time difference, x(n) is the time domain signal, X(k) is the frequency domain signal, N is the length of the signal, k is the frequency domain index, and j is the imaginary unit;

[0033] S2-3, extracting spectral features related to SF6 gas leakage through waveform analysis, wherein the features include the intensity of specific frequency components, changes in frequency distribution, peak positions and numbers, spectral shape and symmetry;

[0034] S2-4, extracting the photoacoustic signal characteristics related to SF6 gas leakage, the photoacoustic signal is the sound wave generated after the gas absorbs light energy, and the photoacoustic signal characteristics include the intensity, frequency and duration of the sound wave.

[0035] Furthermore, in step S3, the following sub-steps are also included:

[0036] S3-1, designing corresponding graphic styles based on the analyzed gas spectrum and photoacoustic signal characteristics, wherein the graphic styles include waveform graphs, spectrum graphs, and spectrograms;

[0037] S3-2, embed the waveform data into the graphic style. The specific formula is:

[0038]

[0039] Where θ is the phase, j is the imaginary unit, and j 2 = -1;

[0040] S3-3, the waveform characteristics, spectrum characteristics and timestamp of SF6 gas are integrated to form a complete sensing waveform. The specific formula is:

[0041]

[0042] Among them, F f is the fused signal, F i is the ith signal, w i is the weight of the ith signal.

[0043] Furthermore, in step S4, the following sub-steps are also included:

[0044] S4-1, the gas ions in the enclosed space are sent into the electric transmission device through the emission source, and the carrier gas ions and SF6 ions undergo ionization reaction under the action of the electric field to form a variety of differentiated ions;

[0045] S4-2, through the electric field effect of the electric field area, the gas ions enter the drift region through the isolation gate, the isolation gate is opened periodically, and the leaked gas ions are detected when passing through the isolation gate;

[0046] S4-3, causing charged ions to collide continuously in the drift region, and separating different gas ions according to the difference in migration rates;

[0047] S4-4, different gas ions pass through the electric field region, isolation gate and drift region three times, and the gas ions are repeatedly separated;

[0048] S4-5, a collection region is set at the end of the drift region to collect gas ions through a collection plate.

[0049] Furthermore, in step S5, the following sub-steps are also included:

[0050] S5-1, the sensing waveform data is transmitted to the gas analyzer, and a gas detection mathematical model is established based on the waveform data. The specific formula of the model is:

[0051]

[0052] Wherein, H0 represents the preset SF6 gas concentration value, H1 represents the SF6 concentration inside the confined space, y”(t) represents the gas expression function model, n(t) represents the internal gas remaining amount, h represents the leakage gas variation coefficient, and x(t) represents the SF6 leakage variable function;

[0053] S5-2, using the differential energy calculation formula in the DED algorithm, perform differential energy calculation on the waveform data. The specific formula is:

[0054]

[0055] Where Y represents the differential energy value, N represents the number of detection devices required, and y i (t represents the detection energy function of a single device;

[0056] S5-3, the differential function is processed together with the confined space SF6 gas detection model function, and the simplified model is:

[0057]

[0058] Among them, λ represents the standard differential energy value of the gas, which is the threshold for judging whether SF6 gas in a confined space is leaking;

[0059] S5-4, perform energy estimation and estimate the differential energy using the following formula:

[0060]

[0061] in, represents the gas leakage budget (no leakage state) in the operation of the confined space, and γ represents the standard differential energy value of the gas;

[0062] S5-5, conduct probability analysis and determine the probability of gas leakage in the presence of differential energy using the following formula:

[0063]

[0064] Among them, P d Indicates the probability of SF6 gas leakage in a confined space, P r represents the gas differential energy set, Γ represents the non-completely controllable variable, and m represents the displayed amount of gas in the confined space;

[0065] S5-6, compare the calculated differential energy value Y with the set threshold λ. If Y>λ, it is judged that there is SF6 gas leakage in the confined space, and the SF6 gas concentration is H1; if Y≤λ, it is judged that the SF6 gas concentration inside the confined space is within the normal range, and the SF6 gas concentration is H0.

[0066] Furthermore, in step S6, the following sub-steps are also included:

[0067] S6-1, organize the received processing results, including classifying and filing the SF6 gas confirmation information, gas volume, and gas location data according to a specific format or standard;

[0068] S6-2, design a suitable test report framework according to the test requirements and application scenarios, the framework including report number, test date, test location, test result summary, and detailed test data;

[0069] S6-3, fill the organized test data into the test report framework, including displaying the SF6 gas confirmation information, SF6 gas quantity estimation, and SF6 gas location in the report in the form of charts, text or tables.

[0070] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0071] The present invention arranges a high-sensitivity sensor in a confined space environment, collects square wave signals generated by SF6 gas leakage, and pre-processes the collected waveform signals; based on the waveform characteristics generated by SF6 leakage ions, the square wave signal is converted into a sine waveform, and the gas spectrum and photoacoustic signal characteristics are extracted through waveform analysis; according to the gas spectrum and photoacoustic signal characteristics, a corresponding graphic style is established, and a sensing waveform is constructed in combination with the waveform conversion result; the SF6 gas ions in the confined space are transferred to a gas analyzer for separation through an electrical transmission method; the differential energy detection (DED) algorithm is used to realize accurate detection of trace SF6 gas concentration in the gas analyzer; and according to the processing result of the DED algorithm, an SF6 gas detection report is output.

[0072] The method of the present invention can capture trace SF6 gas leakage signals and convert them into analyzable waveform data through the application of waveform conversion, electrical transmission method and DED algorithm. This conversion not only improves the accuracy of the data, but also enhances the detection sensitivity of the system, so that even if the concentration of SF6 gas in a confined space is extremely low, it can be accurately detected.

[0073] Compared with traditional detection methods, the method of the present invention realizes rapid processing and analysis of sensor waveform data through advanced algorithm processing technology, thereby greatly shortening the detection time and improving the detection efficiency.

[0074] The present invention can more accurately identify the characteristics of SF6 gas leakage through graphic style establishment and sensor waveform construction. The application of DED algorithm enhances the anti-interference ability of data, reduces the false alarm and missed alarm rates caused by noise, interference and other factors, and can provide users with more accurate detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0076] Figure 1 A flow chart of a method provided by an embodiment of the present invention;

[0077] Figure 2 A detection principle diagram provided for an embodiment of the present invention;

[0078] Figure 3 Schematic diagram of the electrical transmission method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0079] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the detection algorithm of trace SF6 gas in a confined space proposed by the present invention, its specific implementation method, structure, characteristics and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0080] Unless defined otherwise, 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 invention belongs.

[0081] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0082] The specific scheme of the detection algorithm of trace SF6 gas in a confined space provided by the present invention is described in detail below with reference to the accompanying drawings.

[0083] Example

[0084] See also Figure 1 and Figure 2, which shows a method flow chart and a detection principle diagram of a detection algorithm for trace SF6 gas in a confined space provided by an embodiment of the present invention, the method comprising the following steps:

[0085] Step S1, arranging a high-sensitivity sensor in a confined space environment, collecting a square wave signal generated by SF6 gas leakage, and preprocessing the collected waveform signal;

[0086] Wherein step S1 also includes the following sub-steps:

[0087] S1-1, selecting a high-sensitivity sensor according to the characteristics of the confined space and SF6 gas, wherein the high-sensitivity sensor includes an infrared imaging sensor, a laser sensor, and an electrochemical sensor;

[0088] S1-2, start the sensor to collect the square wave signal generated by the SF6 gas leakage, and the sensor can fully cover the confined space;

[0089] S1-4, processing and analyzing the waveform signal collected by the sensor through the TMS+XD joint chip, wherein the processing includes filtering, signal amplification and reduction, and the analysis includes statistical analysis, pattern recognition, and data mining;

[0090] S1-5, filter the waveform signal, amplify and reduce the signal through the following formula:

[0091]

[0092] y(t)=A*x(t)(enlarged)

[0093] y(t)=B*x(t) (reduced, B<1)

[0094] Where y[n] is the filter output, x[n] is the filter input, h[n] is the filter coefficient, N is the filter order; y(t) is the output signal, x(t) is the input signal, A is the amplification gain factor, and B is the reduction gain factor;

[0095] S1-6, perform statistical analysis, pattern recognition, and data mining on the waveform signal using the following formula:

[0096]

[0097] Among them, μ is the mean, x i is the i-th data point in the dataset, N is the total number of data points; w is the weight vector, b is the bias term, ξ is the slack variable, and C is the regularization parameter; J is the objective function of the algorithm, K is the number of clusters, and C k is the kth cluster, μ k is the mean of the kth cluster, x iis a data point.

[0098] It should be noted that the characteristics of confined spaces are limited volume and complex structure, which leads to uneven gas distribution or dead corners; SF6 gas is a colorless, tasteless and odorless gas with high chemical stability and electrical insulation properties, but it may decompose to produce toxic substances under certain conditions, and leakage will cause damage to the environment and equipment.

[0099] Infrared imaging sensors measure the concentration of SF6 gas by detecting its ability to absorb specific infrared wavelengths. They can provide intuitive image displays to help locate the source of leaks. Laser sensors use laser beams to scan confined spaces and detect by measuring the reflection or scattering of laser beams. They have high precision and long-distance detection capabilities. Electrochemical sensors convert SF6 gas into electrical signals through chemical reactions for measurement. They have the characteristics of fast response and high sensitivity.

[0100] When SF6 gas leaks, its concentration change may appear in the form of a square wave signal, which has clear starting and ending points, facilitating subsequent processing and analysis.

[0101] Filtering is the process of filtering the raw data through a specific filter coefficient h[n] and a filter order N to eliminate unnecessary frequency components; amplification and reduction is the process of adjusting the amplitude of the raw data by adjusting the amplification gain factor A and the reduction gain factor B, which helps ensure that the data remains within an appropriate range in subsequent processing.

[0102] Statistical analysis uses the mean as the statistical standard and performs weighted averaging on each data point in the data set to obtain the mean μ of the entire data set; pattern recognition uses the support vector machine (SVM) algorithm for pattern recognition. SVM is a powerful classification algorithm. By training the data set, SVM can find the optimal classification boundary to classify unknown data; data mining selects the K-means algorithm for data mining. K-means is a clustering algorithm that can divide the data set into K clusters, so that the data points in the same cluster are similar to each other, while the data points between different clusters are quite different, which helps to discover potential patterns and structures in the data.

[0103] Step S2: based on the waveform characteristics of SF6 leakage ions, convert the square wave signal into a sinusoidal waveform, and extract the gas spectrum and photoacoustic signal characteristics through waveform analysis;

[0104] Wherein step S2 also includes the following sub-steps:

[0105] S2-1, identify the specific waveform characteristics of the square wave signal generated by the SF6 leakage ions on the sensor, and convert the square wave signal into a sine wave. The specific formula is:

[0106]

[0107] Where y′(t) is the sinusoidal output waveform, A is the amplitude, which indicates the maximum distance the waveform deviates from the equilibrium position, ω is the angular frequency, and φ is the phase angle, which indicates the position of the waveform at time t=0;

[0108] S2-2, performing waveform analysis on the converted sinusoidal waveform, wherein the waveform analysis includes calculating the frequency, amplitude, phase, and periodicity characteristics of the waveform. The specific formula is:

[0109]

[0110] Where f is the frequency, Δt is the time difference, x(n) is the time domain signal, X(k) is the frequency domain signal, N is the length of the signal, k is the frequency domain index, and j is the imaginary unit;

[0111] S2-3, extracting spectral features related to SF6 gas leakage through waveform analysis, wherein the features include the intensity of specific frequency components, changes in frequency distribution, peak positions and numbers, spectral shape and symmetry;

[0112] S2-4, extracting the photoacoustic signal characteristics related to SF6 gas leakage, the photoacoustic signal is the sound wave generated after the gas absorbs light energy, and the photoacoustic signal characteristics include the intensity, frequency and duration of the sound wave.

[0113] It should be noted that the square wave signal has a fixed period and high and low levels, while the sine wave is a continuously changing waveform with a specific amplitude, angular frequency and phase angle.

[0114] The frequency is obtained by calculating the time difference between two adjacent peaks or valleys to obtain the period, and then the frequency is obtained; the amplitude represents the maximum distance that the waveform deviates from the equilibrium position, which can be obtained by measuring the difference between the peak or valley and the equilibrium position; the phase represents the position of the waveform at t=0, which can be obtained by measuring the angle difference between the starting point of the waveform and the equilibrium position; the periodic characteristics can be evaluated by observing the repeatability and stability of the waveform.

[0115] The intensity of specific frequency components can reflect the signal strength generated by SF6 leakage ions on the sensor; the change in frequency distribution can reflect the degree and rate of SF6 leakage; the peak position and number can reflect the complexity and stability of the signal; the spectral shape and symmetry can reflect the overall characteristics and laws of the signal.

[0116] The intensity of the sound wave can reflect the concentration and leakage of SF6 gas; the frequency can reflect the vibration characteristics of the sound wave and the physical properties of SF6 gas; the duration can reflect the duration and stability of SF6 gas leakage.

[0117] Step S3: Establish corresponding graphic styles according to gas spectrum and photoacoustic signal characteristics, and construct sensing waveforms in combination with waveform conversion results;

[0118] Wherein step S3 also includes the following sub-steps:

[0119] S3-1, designing corresponding graphic styles based on the analyzed gas spectrum and photoacoustic signal characteristics, wherein the graphic styles include waveform graphs, spectrum graphs, and spectrograms;

[0120] S3-2, embed the waveform data into the graphic style. The specific formula is:

[0121]

[0122] Where θ is the phase, j is the imaginary unit, and j 2 = -1;

[0123] S3-3, the waveform characteristics, spectrum characteristics and timestamp of SF6 gas are integrated to form a complete sensing waveform. The specific formula is:

[0124]

[0125] Among them, F f is the fused signal, F i is the ith signal, w i is the weight of the ith signal.

[0126] It should be noted that the waveform graph shows the change of the gas spectrum over time. Through the waveform graph, the amplitude, frequency and phase information of the signal can be intuitively seen.

[0127] The spectrogram decomposes the frequency components of the gas spectrum and displays them on a graph, which helps to understand the frequency distribution of the signal and analyze which frequency components dominate the signal.

[0128] A spectrogram is similar to a frequency spectrum diagram, but it focuses more on showing the frequency and time relationship of a sound signal. For photoacoustic signals, a spectrogram can reveal the frequency components of a sound signal that change over time, which helps analyze the generation and propagation mechanism of sound.

[0129] Step S4, transferring the SF6 gas ions in the confined space to the gas analyzer for separation by electrical transport method;

[0130] See also Figure 3 , which shows a schematic diagram of the electrical transmission method of a detection algorithm for trace SF6 gas in a confined space provided by an embodiment of the present invention.

[0131] Wherein step S4 also includes the following sub-steps:

[0132] S4-1, the gas ions in the enclosed space are sent into the electric transmission device through the emission source, and the carrier gas ions and SF6 ions undergo ionization reaction under the action of the electric field to form a variety of differentiated ions;

[0133] S4-2, through the electric field effect of the electric field area, the gas ions enter the drift region through the isolation gate, the isolation gate is opened periodically, and the leaked gas ions are detected when passing through the isolation gate;

[0134] S4-3, causing charged ions to collide continuously in the drift region, and separating different gas ions according to the difference in migration rates;

[0135] S4-4, different gas ions pass through the electric field region, isolation gate and drift region three times, and the gas ions are repeatedly separated;

[0136] S4-5, a collection region is set at the end of the drift region to collect gas ions through a collection plate.

[0137] It should be noted that the emission source is a device capable of generating ions, and in this embodiment it is electrospray. The separation source is an ionization chamber, which is used to promote the ionization of gas molecules. The various ions generated by the ionization reaction include carrier gas ions and SF6 ions.

[0138] The electric field region is used to accelerate the ions so that they obtain sufficient kinetic energy to enter the drift region. The isolation gate controls the time when the ions enter the drift region by periodically opening and closing, which helps to synchronize the detection and data analysis of the ions. When the ions pass through the isolation gate, a microcurrent detector is used to monitor the presence and number of ions.

[0139] The drift region is a long and narrow area in which the electric field causes the ions to migrate. The migration rate of ions in the drift region depends on their mass, charge and collision frequency with other molecules. Different types of ions migrate at different speeds. The ion separation effect can be optimized by adjusting the electric field strength and the length of the drift region.

[0140] The collector plate is an electrode located at the end of the drift zone, which is used to capture and collect separated ions. When ions hit the collector plate, current or charge changes will occur. The changes can be recorded by the detector. The detector can record the number and type of ions. The number of ions is the current intensity, and the type of ions is determined by the migration time and / or mass and charge ratio.

[0141] To ensure efficient ion separation, different gas ions need to pass through the electric field zone, isolation gate and drift zone multiple times, which is called "multi-stage separation". By repeating these steps multiple times, the separation and purity of the ions can be further improved. Each time the ions pass, they will be further separated according to the difference in migration rate, thereby obtaining a clearer ion spectrum.

[0142] Step S5, realizing accurate detection of trace SF6 gas concentration in the gas analyzer by using a differential energy detection (DED) algorithm;

[0143] Wherein, in step S5, the following sub-steps are also included:

[0144] S5-1, the sensing waveform data is transmitted to the gas analyzer, and a gas detection mathematical model is established based on the waveform data. The specific formula of the model is:

[0145]

[0146] Wherein, H0 represents the preset SF6 gas concentration value, H1 represents the SF6 concentration inside the confined space, y”(t) represents the gas expression function model, n(t) represents the internal gas remaining amount, h represents the leakage gas variation coefficient, and x(t) represents the SF6 leakage variable function;

[0147] S5-2, using the differential energy calculation formula in the DED algorithm, perform differential energy calculation on the waveform data. The specific formula is:

[0148]

[0149] Where Y represents the differential energy value, N represents the number of detection devices required, and y i (t represents the detection energy function of a single device;

[0150] S5-3, the differential function is processed together with the confined space SF6 gas detection model function, and the simplified model is:

[0151]

[0152] Among them, λ represents the standard differential energy value of the gas, which is the threshold for judging whether SF6 gas in a confined space is leaking;

[0153] S5-4, perform energy estimation and estimate the differential energy using the following formula:

[0154]

[0155] in, represents the gas leakage budget (no leakage state) in the operation of the confined space, and γ represents the standard differential energy value of the gas;

[0156] S5-5, conduct probability analysis and determine the probability of gas leakage in the presence of differential energy using the following formula:

[0157]

[0158] Among them, P d Indicates the probability of SF6 gas leakage in a confined space, P r represents the gas differential energy set, Γ represents the non-completely controllable variable, and m represents the displayed amount of gas in the confined space;

[0159] S5-6, compare the calculated differential energy value Y with the set threshold λ. If Y>λ, it is judged that there is SF6 gas leakage in the confined space, and the SF6 gas concentration is H1; if Y≤λ, it is judged that the SF6 gas concentration inside the confined space is within the normal range, and the SF6 gas concentration is H0.

[0160] It should be noted that the concentration and leakage of SF6 gas can be quantitatively described through the gas detection mathematical model; the differential energy value can reflect the changes in the waveform data, especially the changes caused by the change of SF6 gas concentration, which is helpful to detect gas leakage; the simplified model is used to determine whether SF6 gas is leaking in a confined space, which is achieved by comparing the gas standard differential energy value with the threshold; energy estimation helps to further understand the leakage of SF6 gas; probability analysis can quantitatively describe the possibility of SF6 gas leakage; and by setting the threshold, the SF6 gas concentration can be accurately detected.

[0161] Step S6: outputting the SF6 gas detection report according to the processing result of the DED algorithm;

[0162] Wherein, in step S6, the following sub-steps are also included:

[0163] S6-1, organize the received processing results, including classifying and filing the SF6 gas confirmation information, gas volume, and gas location data according to a specific format or standard;

[0164] S6-2, design a suitable test report framework according to the test requirements and application scenarios, the framework including report number, test date, test location, test result summary, and detailed test data;

[0165] S6-3, fill the organized test data into the test report framework, including displaying the SF6 gas confirmation information, SF6 gas quantity estimation, and SF6 gas location in the report in the form of charts, text or tables.

[0166] It should be noted that the received data is classified according to a specific format or standard, and the confirmation information of SF6 gas (whether it exists, concentration range, etc.) is archived separately; the gas quantity (volume, mass) is classified according to different time intervals or spatial locations; and the gas location data (latitude and longitude, floor, room number) is organized.

[0167] Choose the appropriate report format and style based on the application scenario and reader needs. For technical reports, pay more attention to the accuracy and detail of the data. For management reports, pay more attention to the summary and readability of the results. In order to display the data more intuitively, you can use charts to show the concentration distribution and change trend of SF6 gas, and use text descriptions to explain and supplement the charts to ensure that readers can accurately understand the information expressed by the data.

[0168] The test result overview is a summary section that summarizes the main findings of the test results and can point out the presence and concentration range of SF6 gas. The detailed test data is the core part of the report and is used to display specific test data. The data should be presented in a clear and easy-to-understand manner, including confirmation information of SF6 gas, estimated gas volume, and gas location.

[0169] In this way, a detection algorithm for trace SF6 gas in a confined space can improve data accuracy and enhance detection sensitivity, so that even extremely low concentrations of SF6 gas in a confined space can be accurately detected.

[0170] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A detection algorithm for trace SF6 gas in a confined space, characterized in that: The method includes: Step S1, arranging a high-sensitivity sensor in a confined space environment, collecting a square wave signal generated by SF6 gas leakage, and preprocessing the collected waveform signal; Step S2, based on the waveform characteristics generated by the SF6 leakage ions, convert the square wave signal into a sine waveform, and extract the gas spectrum and photoacoustic signal characteristics through waveform analysis; Step S3, establishing a corresponding graphic style according to the gas spectrum and photoacoustic signal characteristics, and constructing a sensing waveform in combination with the waveform conversion result; Step S4, transferring the SF6 gas ions in the enclosed space to the gas analyzer for separation by electrical transport method; Step S5, realizing accurate detection of trace SF6 gas concentration in the gas analyzer by using a differential energy detection (DED) algorithm; Step S6: outputting the SF6 gas detection report according to the processing result of the DED algorithm.

2. The detection algorithm of trace SF6 gas in a confined space according to claim 1, characterized in that: Wherein step S1 also includes the following sub-steps: S1-1, selecting a high-sensitivity sensor according to the characteristics of the confined space and SF6 gas, wherein the high-sensitivity sensor includes an infrared imaging sensor, a laser sensor, and an electrochemical sensor; S1-2, start the sensor to collect the square wave signal generated by the SF6 gas leakage, and the sensor can fully cover the confined space; S1-4, processing and analyzing the waveform signal collected by the sensor through the TMS+XD joint chip, wherein the processing includes filtering, signal amplification and reduction, and the analysis includes statistical analysis, pattern recognition, and data mining; S1-5, filter the waveform signal, amplify and reduce the signal through the following formula: y(t)=A*x(t)(enlarged) y(t)=B*x(t) (reduced, B<1) Where y[n] is the filter output, x[n] is the filter input, h[n] is the filter coefficient, N is the filter order; y(t) is the output signal, x(t) is the input signal, A is the amplification gain factor, and B is the reduction gain factor; S1-6, perform statistical analysis, pattern recognition, and data mining on the waveform signal using the following formula: Among them, μ is the mean, x i is the i-th data point in the dataset, N is the total number of data points; w is the weight vector, b is the bias term, ξ is the slack variable, and C is the regularization parameter; J is the objective function of the algorithm, K is the number of clusters, and C k is the kth cluster, μ k is the mean of the kth cluster, x i is a data point.

3. The detection algorithm of trace SF6 gas in a confined space according to claim 1, characterized in that: Wherein, in step S2, the following sub-steps are also included: S2-1, identify the specific waveform characteristics of the square wave signal generated by the SF6 leakage ions on the sensor, and convert the square wave signal into a sine wave. The specific formula is: Where y′(t) is the sinusoidal output waveform, A is the amplitude, which indicates the maximum distance the waveform deviates from the equilibrium position, ω is the angular frequency, and φ is the phase angle, which indicates the position of the waveform at time t=0; S2-2, performing waveform analysis on the converted sinusoidal waveform, wherein the waveform analysis includes calculating the frequency, amplitude, phase, and periodicity characteristics of the waveform. The specific formula is: f=ω / 2π Where f is the frequency, Δt is the time difference, x(n) is the time domain signal, X(k) is the frequency domain signal, N is the length of the signal, k is the frequency domain index, and j is the imaginary unit; S2-3, extracting spectral features related to SF6 gas leakage through waveform analysis, wherein the features include the intensity of specific frequency components, changes in frequency distribution, peak positions and numbers, spectral shape and symmetry; S2-4, extracting the photoacoustic signal characteristics related to SF6 gas leakage, the photoacoustic signal is the sound wave generated after the gas absorbs light energy, and the photoacoustic signal characteristics include the intensity, frequency and duration of the sound wave.

4. The detection algorithm of trace SF6 gas in a confined space according to claim 1, characterized in that: Wherein step S3 also includes the following sub-steps: S3-1, designing corresponding graphic styles based on the analyzed gas spectrum and photoacoustic signal characteristics, wherein the graphic styles include waveform graphs, spectrum graphs, and spectrograms; S3-2, embed the waveform data into the graphic style. The specific formula is: Where θ is the phase, j is the imaginary unit, and j 2 = -1; S3-3, the waveform characteristics, spectrum characteristics and timestamp of SF6 gas are integrated to form a complete sensing waveform. The specific formula is: Among them, F f is the fused signal, F i is the ith signal, w i is the weight of the ith signal.

5. The detection algorithm of trace SF6 gas in a confined space as claimed in claim 1, characterized in that: Wherein step S4 also includes the following sub-steps: S4-1, the gas ions in the enclosed space are sent into the electric transmission device through the emission source, and the carrier gas ions and SF6 ions undergo ionization reaction under the action of the electric field to form a variety of differentiated ions; S4-2, through the electric field effect of the electric field area, the gas ions enter the drift region through the isolation gate, the isolation gate is opened periodically, and the leaked gas ions are detected when passing through the isolation gate; S4-3, causing charged ions to collide continuously in the drift region, and separating different gas ions according to the difference in migration rates; S4-4, different gas ions pass through the electric field region, isolation gate and drift region multiple times to repeatedly separate the gas ions; S4-5, a collection region is set at the end of the drift region to collect gas ions through a collection plate.

6. The detection algorithm of trace SF6 gas in a confined space according to claim 1, characterized in that: Wherein, in step S5, the following sub-steps are also included: S5-1, the sensing waveform data is transmitted to the gas analyzer, and a gas detection mathematical model is established based on the waveform data. The specific formula of the model is: Wherein, H0 represents the preset SF6 gas concentration value, H1 represents the SF6 concentration inside the confined space, y”(t) represents the gas expression function model, n(t) represents the internal gas remaining amount, h represents the leakage gas variation coefficient, and x(t) represents the SF6 leakage variable function; S5-2, using the differential energy calculation formula in the DED algorithm, perform differential energy calculation on the waveform data. The specific formula is: Where Y represents the differential energy value, N represents the number of detection devices required, and y i (t represents the detection energy function of a single device; S5-3, the differential function is processed together with the confined space SF6 gas detection model function, and the simplified model is: Among them, λ represents the standard differential energy value of the gas, which is the threshold for judging whether SF6 gas in a confined space is leaking; S5-4, perform energy estimation and estimate the differential energy using the following formula: in, represents the gas leakage budget (no leakage state) in the operation of the confined space, and γ represents the standard differential energy value of the gas; S5-5, conduct probability analysis and determine the probability of gas leakage in the presence of differential energy using the following formula: Among them, P d Indicates the probability of SF6 gas leakage in a confined space, P r represents the gas differential energy set, Γ represents the non-completely controllable variable, and m represents the displayed amount of gas in the confined space; S5-6, compare the calculated differential energy value Y with the set threshold λ. If Y>λ, it is judged that there is SF6 gas leakage in the confined space, and the SF6 gas concentration is H1; if Y≤λ, it is judged that the SF6 gas concentration inside the confined space is within the normal range, and the SF6 gas concentration is H0.

7. The detection algorithm of trace SF6 gas in a confined space according to claim 1, characterized in that: Wherein, in step S6, the following sub-steps are also included: S6-1, organize the received processing results, including classifying and filing the SF6 gas confirmation information, gas volume, and gas location data according to a specific format or standard; S6-2, design a suitable test report framework according to the test requirements and application scenarios, the framework including report number, test date, test location, test result summary, and detailed test data; S6-3, fill the organized test data into the test report framework, including displaying the SF6 gas confirmation information, SF6 gas quantity estimation, and SF6 gas location in the report in the form of charts, text or tables.

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