Gas chamber conditioning method for SF6 leak detection sensor

Abstract

The application provides a gas chamber adjusting method using an SF6 leakage detection sensor, and belongs to the technical field of gas chamber adjusting, which comprises the following steps: step 1, collecting parameters of an online monitoring device for quantitatively detecting SF6 gas leakage based on ultrasonic waves; step 2, constructing a multi-parameter compensation model for the online monitoring device for quantitatively detecting SF6 gas leakage based on ultrasonic waves; step 3, calculating the SF6 concentration based on the corrected real phase difference; and step 4, verifying and outputting the data according to the calculated SF6 concentration. The application collects environmental parameters by introducing a gas pressure sensor and a humidity sensor, establishes a multi-parameter compensation model containing temperature, gas pressure and humidity, corrects the ultrasonic wave propagation speed and the calculation result of the SF6 concentration, controls the system error within ±2%, and improves the detection precision and environmental adaptability.

Description

Gas chamber adjustment method using SF6 leak detection sensors Technical Field

[0001] This invention belongs to the field of gas chamber regulation technology, specifically relating to a gas chamber regulation method using an SF6 leak detection sensor. Background Technology

[0002] In the power industry, SF6 gas is widely used in current transformers, voltage transformers, and other equipment in GIS substations due to its excellent insulation and arc-quenching properties. To ensure the safe operation of equipment and personnel, real-time detection of SF6 gas leakage is necessary through online monitoring devices. While the existing online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound, as described in patent publication number "CN207066691U," improves detection resolution and data processing efficiency through a dual-chamber design (background gas chamber and measured gas chamber) and a CPLD signal processing module, it still has key shortcomings:

[0003] Current technologies only consider the effect of temperature on the propagation speed of ultrasound, using a dual-chamber differential algorithm to eliminate some temperature interference, but they fail to address the systematic errors caused by changes in air pressure and humidity. In practical applications, the air pressure in the environment of GIS substations fluctuates with weather and altitude, while humidity varies with season and ventilation conditions. The propagation speed of ultrasound in gas is positively correlated with air pressure and non-linearly correlated with humidity. That is, increased air pressure leads to increased gas molecule density, resulting in faster ultrasound propagation speed; increased humidity alters the equivalent density and elastic modulus of the gas medium, causing the ultrasound propagation speed to deviate from the standard value.

[0004] Because existing methods do not compensate for air pressure and humidity parameters, when the on-site air pressure and humidity deviate from the standard operating conditions (standard atmospheric pressure 101.325 kPa, relative humidity 50%), it will cause the calculation of the propagation speed of ultrasonic waves in the background gas chamber and the measured gas chamber to be inaccurate. This will lead to a systematic error of ±5% to ±8% in the SF6 concentration detection results, which cannot meet the requirements of high-precision monitoring (the power industry requires SF6 leakage detection accuracy of ≤±2%). Summary of the Invention

[0005] The purpose of this invention is to provide a gas chamber adjustment method using an SF6 leak detection sensor. By introducing a pressure sensor and a humidity sensor to collect environmental parameters, a multi-parameter compensation model including temperature, pressure, and humidity is established to correct the ultrasonic propagation speed and SF6 concentration calculation results, thereby controlling the system error within ±2% and improving detection accuracy and environmental adaptability.

[0006] The present invention employs the following technical solution.

[0007] A gas chamber adjustment method using an SF6 leak detection sensor, applied to an online monitoring device for quantitative detection of SF6 gas leaks based on ultrasound, includes:

[0008] Step 1: Collect parameters for the online monitoring device that uses ultrasound to quantitatively detect SF6 gas leaks;

[0009] Step 2: Construct a multi-parameter compensation model for the online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound;

[0010] Step 3: Calculate the SF6 concentration based on the corrected true phase difference;

[0011] Step 4: Verify and output the calculated SF6 concentration data.

[0012] Preferably, step 1 specifically includes:

[0013] Step 1-1: Add a pressure sensor and a humidity sensor to the outside of the gas chamber of the online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound. The pressure sensor, humidity sensor and temperature sensor of the online monitoring device are connected to the ARM module together.

[0014] Step 1-2: When the detection is started, the ARM module of the online monitoring device receives the synchronously acquired field environmental parameters and transmits the field environmental parameters to the CPLD signal processing module. The field environmental parameters include temperature T, air pressure P, and relative humidity RH data that are synchronously acquired and transmitted to the ARM module by temperature sensor, air pressure sensor, and humidity sensor, respectively.

[0015] Steps 1-3: The ultrasonic transducer module of the online monitoring device transmits ultrasonic signal S1 to the background gas chamber and ultrasonic signal S2 to the gas chamber under test, according to the existing dual-chamber detection logic. The CPLD signal processing module receives the echoes of the two ultrasonic signals and calculates the phase difference as the original phase difference Δφ0.

[0016] Preferably, step 2 specifically includes:

[0017] Step 2-1: Correct the ultrasonic propagation speed by combining the gas component correction factor, temperature and parameter synergy coefficient, and nonlinear compensation term;

[0018] Step 2-2: Compensate for the phase difference based on the corrected ultrasonic wave propagation speed.

[0019] Preferably, step 2-1 specifically includes:

[0020] Step 2-1-1: Calculate the ultrasonic propagation speed under standard operating conditions;

[0021] Step 2-1-2: Correct the ultrasonic propagation speed under actual working conditions.

[0022] Preferably, in step 2-1-1, the formula for calculating the ultrasonic propagation speed under standard operating conditions is:

[0023] ;

[0024] in The speed of ultrasonic wave propagation under standard operating conditions; This refers to the specific heat ratio of the gas. The gas constant is... The temperature is the standard operating temperature. denoted as the molar mass of the gas.

[0025] Preferably, in step 2-1-1, the air pressure under standard operating conditions... =101.325kPa, humidity under standard operating conditions =50%;

[0026] When the gas is the air in the background gas chamber under standard operating conditions. =1.4, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. =1.06;

[0027] When the gas is the air in the background gas chamber under standard operating conditions. =287 J / (kg・K), when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. =65.7J / (kg・K));

[0028] Including the speed of ultrasonic wave propagation in a background gas chamber under standard operating conditions. The ultrasonic propagation speed in a background gas chamber containing a mixture of SF6 and air under standard operating conditions. .

[0029] Preferably, step 2-1-2 specifically includes:

[0030] Apply the following modified formula for multi-dimensional coupling:

[0031] ;

[0032] in This is the corrected ultrasonic propagation speed under actual working conditions; The speed of ultrasonic wave propagation under standard operating conditions; This is actual air pressure data; The air pressure is under standard operating conditions. This is actual humidity data; Humidity under standard operating conditions; This is actual temperature data; This is the pressure linearity correction factor; This is the pressure nonlinearity correction coefficient; This is the humidity baseline correction factor; The temperature and parameter compatibility coefficient; For gas component correction factors; This is a nonlinear compensation term.

[0033] Preferably, in step 2-1-2, when the gas is air from the background gas chamber under standard operating conditions, The value is 0.85, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. The value is 0.62;

[0034] The value is -0.12;

[0035] When the gas is the air in the background gas chamber under standard operating conditions. The value is 0.08, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. The value is 0.11;

[0036] ,in ;

[0037] ,in This is actual oxygen concentration data; The oxygen concentration in standard air is 21%.

[0038] Including the ultrasonic propagation speed when the gas is air in the background gas chamber under actual operating conditions. The ultrasonic propagation speed in a background gas chamber containing a mixture of SF6 and air under actual operating conditions. .

[0039] Preferably, step 2-2 specifically includes:

[0040] The original phase difference Δφ0 is corrected to the true phase difference Δφ using the following formula from the multi-parameter compensation model:

[0041] ;

[0042] in The speed of ultrasonic wave propagation is given by the gas being air in a background gas chamber under standard operating conditions. The ultrasonic wave propagation speed is given by the standard operating condition of a mixture of SF6 and air in a background gas chamber. The speed of ultrasonic wave propagation is given when the gas is air in the background gas chamber under actual working conditions. The ultrasonic propagation speed is given by the background gas chamber containing a mixture of SF6 and air under actual operating conditions.

[0043] Preferably, step 3 specifically includes:

[0044] Based on the corrected true phase difference Δφ and the dual-chamber acoustic path L, the SF6 concentration is calculated. :

[0045] ;

[0046] in The center frequency of the ultrasound. This is the coupling coefficient between the phase difference and the sound path, used to convert the corrected true phase difference into a concentration ratio.

[0047] Preferably, step 4 specifically includes:

[0048] The CPLD signal processing module will calculate the SF6 concentration. The data is transmitted to the ARM module, which then combines the actual oxygen concentration data collected and transmitted from the oxygen sensor. ,right Secondary verification: If the actual oxygen concentration data If the deviation is 21% ± 1%, it will be corrected using the following formula. And obtain the corrected SF6 concentration :

[0049] ;

[0050] in The oxygen concentration in standard air is 21%.

[0051] Next, the final corrected SF6 concentration will be... The data is transmitted via the ARM module to a PC connected to the ARM module, and the SF6 concentration is displayed in real time on the PC. .

[0052] The beneficial effects of the present invention are as follows: Compared with the prior art, the technical effects of the present invention include:

[0053] Eliminating multi-parameter system errors: By introducing air pressure sensors and humidity sensors, a multi-parameter compensation model is established, and the influence of air pressure and humidity on ultrasonic propagation speed is quantified into compensation coefficients, reducing the SF6 concentration detection error from the existing ±5%~±8% to within ±2%, meeting the high-precision monitoring needs of the power industry.

[0054] Improved environmental adaptability: The compensation model covers a temperature range of 0℃ to 60℃, an air pressure range of 80kPa to 120kPa, and a humidity range of 20%RH to 80%RH, which can adapt to the field environment of GIS substations in different regions and seasons, and solve the problem of the sharp drop in accuracy of traditional devices in complex environments.

[0055] Enhanced detection reliability: By combining secondary verification of oxygen concentration, interference from abnormal air composition (such as hypoxia or hyperxia) on the detection of mixed gases is eliminated, further ensuring the authenticity of the concentration estimation results;

[0056] High compatibility: No need to change the dual-chamber and CPLD / ARM hardware architecture of the existing detection device. Only the addition of air pressure and humidity sensors and the upgrading of the algorithm are required. It can be directly applied to the modification of existing SF6 leak detection sensors, reducing the cost of technology promotion. Attached Figure Description

[0057] Figure 1 is a flowchart of the gas chamber adjustment method using an SF6 leak detection sensor described in this invention. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, any other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0059] As shown in Figure 1, the gas chamber adjustment method using an SF6 leak detection sensor described in this invention is applied to an online monitoring device for quantitative detection of SF6 gas leaks based on ultrasound, which includes a CPLD signal processing module, an ARM module, dual chambers (background gas chamber and measured gas chamber), an ultrasonic transducer module, a temperature sensor, and an oxygen sensor, as described in patent publication number "CN207066691U". The device comprises:

[0060] Step 1: Collect parameters for the online monitoring device that uses ultrasound to quantitatively detect SF6 gas leaks;

[0061] In a preferred but non-limiting embodiment of the present invention, step 1 specifically includes:

[0062] Step 1-1: Add a pressure sensor (accuracy ≤ ±0.1 kPa) and a humidity sensor (accuracy ≤ ±3% RH) to the outside of the gas chamber of the online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound. The pressure sensor and humidity sensor are connected to the ARM module together with the temperature sensor and oxygen sensor of the online monitoring device.

[0063] Steps 1-2: When the detection is started, the ARM module of the online monitoring device receives the synchronously acquired field environmental parameters and transmits them to the CPLD signal processing module via the RS232 bus. The field environmental parameters include temperature T (unit: K), air pressure P (unit: kPa), and relative humidity RH (unit: %) data, which are synchronously acquired and transmitted to the ARM module by temperature sensor, air pressure sensor, and humidity sensor, respectively. The CPLD signal processing module and the ARM module are connected via the RS232 bus.

[0064] Steps 1-3: The ultrasonic transducer module of the online monitoring device transmits ultrasonic signal S1 to the background gas chamber (filled with standard dry air, SF6 concentration is 0) and ultrasonic signal S2 to the gas chamber under test (inhaled mixed gas). The CPLD signal processing module receives the echoes of the two ultrasonic signals and calculates the phase difference as the original phase difference Δφ0 (unit: rad).

[0065] Step 2: Construct a multi-parameter compensation model for the online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound;

[0066] The multi-parameter compensation model includes combining gas component correction factors, temperature and parameter synergy coefficients, and nonlinear compensation terms to correct the ultrasonic propagation velocity, and then compensating for the phase difference based on the corrected ultrasonic propagation velocity.

[0067] In a preferred but non-limiting embodiment of the present invention, step 2 specifically includes:

[0068] Step 2-1: Correct the ultrasonic propagation speed by combining the gas component correction factor, temperature and parameter synergy coefficient, and nonlinear compensation term;

[0069] In a preferred but non-limiting embodiment of the present invention, step 2-1 specifically includes:

[0070] Step 2-1-1: Calculate the ultrasonic propagation speed under standard operating conditions;

[0071] In a preferred but non-limiting embodiment of the present invention, in step 2-1-1, the formula for calculating the ultrasonic wave propagation speed under standard operating conditions is:

[0072] Based on the theory of gas molecule motion, the standard formula for calculating the propagation speed of ultrasound in a gas, that is, the formula for calculating the propagation speed of ultrasound under standard operating conditions, is as follows:

[0073] ;

[0074] in The ultrasonic propagation speed under standard operating conditions (unit: m / s). This refers to the specific heat ratio of the gas. The gas constant is... The temperature is the standard operating temperature (25℃, or 298.15 K). The molar mass of the gas is expressed in kg / mol. The molar mass of the gas can be collected and transmitted to the ARM module via a gas chromatograph connected to the ARM module.

[0075] In a preferred but non-limiting embodiment of the present invention, in step 2-1-1, the air pressure under standard operating conditions... =101.325kPa, humidity under standard operating conditions =50%;

[0076] When the gas is the air in the background gas chamber under standard operating conditions. =1.4, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. =1.06;

[0077] When the gas is the air in the background gas chamber under standard operating conditions. =287 J / (kg・K), when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. =65.7J / (kg・K));

[0078] Including the speed of ultrasonic wave propagation in a background gas chamber under standard operating conditions. The ultrasonic propagation speed in a background gas chamber containing a mixture of SF6 and air under standard operating conditions. .

[0079] Step 2-1-2: Correct the ultrasonic propagation speed under actual working conditions.

[0080] In a preferred but non-limiting embodiment of the present invention, step 2-1-2 specifically includes:

[0081] Traditional methods for correcting the ultrasonic propagation speed under actual operating conditions involve introducing air pressure and humidity compensation coefficients. This means multiplying the air pressure and humidity compensation coefficients by the ultrasonic propagation speed under standard operating conditions to correct the actual ultrasonic propagation speed. However, these traditional methods have the following key drawbacks:

[0082] The dynamic nonlinear relationship of parameters is not considered: the influence of air pressure and humidity on the propagation speed is simplified to a linear product relationship. However, in reality, the propagation speed of ultrasound is positively correlated with air pressure (the speed increases at high air pressure), and has a nonlinear simple quadratic relationship with humidity (the influence of humidity varies significantly at different temperatures). The linear simplification correction cannot match the real physical laws.

[0083] Ignoring the coupling effect of gas components: When distinguishing the differences in the effects of air pressure and humidity in pure air and SF6 mixed with air (SF6 has a large molecular mass, and the effect of air pressure changes on its molecular motion is weaker than that of air), a unified correction coefficient leads to the amplification of errors in the mixed gas scenario;

[0084] Lack of temperature and parameter synergistic correction: Temperature directly affects the propagation speed by changing the kinetic energy of gas molecules, and at the same time, it indirectly changes the degree of influence of air pressure and humidity on speed (for example, the influence coefficient of humidity on speed at high temperature is 1.5 times that at low temperature). Existing methods do not reflect this synergistic effect.

[0085] To address the aforementioned shortcomings, a gas composition correction factor, a temperature and parameter synergy coefficient, and a nonlinear compensation term are introduced to construct and execute the following multi-dimensional coupled correction formula:

[0086] ;

[0087] in This is the corrected ultrasonic propagation speed under actual working conditions; The speed of ultrasonic wave propagation under standard operating conditions; This refers to the actual air pressure value collected by the air pressure sensor, which is the actual air pressure data. The air pressure is under standard operating conditions. This refers to the actual humidity value collected by the humidity sensor, which is the actual humidity data. Humidity under standard operating conditions; The actual temperature value collected by the temperature sensor at the site, that is, the actual temperature data; This is the pressure linearity correction factor; This is the pressure nonlinearity correction coefficient; This is the humidity baseline correction factor; The temperature and parameter compatibility coefficient; For gas component correction factors; This is a nonlinear compensation term.

[0088] In a preferred but non-limiting embodiment of the present invention, in step 2-1-2, This represents the linear component of the effect of air pressure on velocity, assuming the gas is air in the background gas chamber under standard operating conditions. The value is 0.85, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. The value is 0.62;

[0089] This represents the nonlinear component of the effect of air pressure on speed, compensating for the slowdown in speed increase at high air pressure. The value is uniformly set to -0.12 (experimental fitted value);

[0090] The baseline intensity representing the effect of humidity on velocity is given when the gas is air in the background gas chamber under standard operating conditions. The value is 0.08, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. The value is 0.11 (the effect of water molecules is more significant in the mixed gas).

[0091] This indicates the moderating effect of temperature on humidity. ,in ( (These are dimensionless experimental fitting coefficients, obtained through calibration using full-condition data).

[0092] This indicates a characteristic correction based on SF6 concentration. ,in The actual oxygen concentration value collected by the oxygen sensor and transmitted to the ARM module is the actual oxygen concentration data. The oxygen concentration in standard air is 21%.

[0093] Including the ultrasonic propagation speed when the gas is air in the background gas chamber under actual operating conditions. The ultrasonic propagation speed in a background gas chamber containing a mixture of SF6 and air under actual operating conditions. .

[0094] The technical effects of the modified formula for multi-dimensional coupling are as follows:

[0095] (i) Accurately quantify nonlinear relationships to improve correction accuracy:

[0096] By introducing the quadratic term of air pressure It effectively compensates for the nonlinear characteristics of the high-pressure range. In the 110kPa~120kPa range (more than 10% above the standard pressure), the traditional method causes a velocity correction deviation of ±1.8m / s due to the linear assumption, while the improved formula controls the deviation within ±0.5m / s through nonlinear compensation, improving the correction accuracy by 72%.

[0097] (ii) Differentiate gas component differences to adapt to mixed gas scenarios:

[0098] Designed to address the differences in physical properties between SF6 and air , Component differentiation values ​​and factor:

[0099] In a mixed gas with an SF6 concentration of 2%, the traditional method, due to the use of correction factors for the air scene, results in a velocity calculation deviation of ±2.3 m / s.

[0100] The improved formula for multidimensional coupling is derived using α = 0.62 (lower than 0.85 for air), γ = 0.11 (higher than 0.08 for air), and... With a co-correction of 0.996, the deviation is reduced to ±0.7m / s, meeting the high-precision requirements for mixed gas detection.

[0101] (III) Coupling the temperature-humidity synergistic effect to expand the adaptability to operating conditions:

[0102] pass The coefficient quantifies the moderating effect of temperature on humidity in high temperature and high humidity scenarios (T=333.15K,

[0103] RH=80%)

[0104] Traditional methods do not take into account the enhanced effect of temperature on humidity, resulting in a speed correction deviation of ±3.1 m / s;

[0105] In the improved formula for multidimensional coupling =1.175 (a 35K increase in temperature leads to a 17.5% increase in the effect of humidity), the corrected deviation is reduced to ±0.9m / s, which improves the applicability of the improved multi-dimensional coupling correction formula by 50% across the entire temperature range of -20℃ to 60℃.

[0106] (iv) Directly improve the accuracy of SF6 concentration detection:

[0107] The propagation speed of ultrasound is a core parameter for estimating SF6 concentration; improving the accuracy of speed correction directly reduces concentration detection errors.

[0108] Under complex operating conditions (low temperature -10℃, high pressure 115kPa, high humidity 70%), traditional methods result in an error of ±3.2% in SF6 concentration detection.

[0109] The improved multi-dimensional coupling correction formula controls the concentration error within ±1.1% through multi-dimensional correction, which is better than the industry's ±2% accuracy standard, providing more reliable monitoring data for the safe operation of equipment.

[0110] This improved multi-dimensional coupling correction formula, by introducing several innovative correction mechanisms, breaks through the limitations of traditional linear correction and significantly improves the accuracy and environmental adaptability of ultrasonic propagation speed correction.

[0111] Step 2-2: Compensate for the phase difference based on the corrected ultrasonic wave propagation speed.

[0112] In a preferred but non-limiting embodiment of the present invention, step 2-2 specifically includes:

[0113] The original phase difference Δφ0 is affected by temperature, air pressure, and humidity, and needs to be corrected to the true phase difference Δφ using the following formula from a multi-parameter compensation model:

[0114] ;

[0115] in The speed of ultrasonic wave propagation is given by the gas being air in a background gas chamber under standard operating conditions. The ultrasonic wave propagation speed is given by the standard operating condition of a mixture of SF6 and air in a background gas chamber. The speed of ultrasonic wave propagation is given when the gas is air in the background gas chamber under actual working conditions. The ultrasonic propagation speed is given by the background gas chamber containing a mixture of SF6 and air under actual operating conditions.

[0116] The essence of the phase difference correction formula in step 2-2 is "to separate environmental interference from concentration signals by normalizing the ultrasonic velocity under standard operating conditions". Its technical effect can be summarized as follows:

[0117] Environmental adaptability: It enables phase difference detection to maintain accuracy in complex environments (high temperature, high pressure, high humidity), overcoming the limitation of traditional methods that are "accurate only under standard operating conditions";

[0118] Detection accuracy: The phase difference correction deviation is controlled within ±1.8%, supporting SF6 concentration detection error ≤±2%, meeting the requirements of high-precision monitoring;

[0119] Device reliability: The stable linear correlation between concentration and phase difference reduces calibration frequency, lowers maintenance costs, and ensures the long-term operation of the online monitoring device.

[0120] In short, this formula is the key bridge connecting "raw phase difference acquisition" and "precise concentration calculation", and directly determines the core performance of the online monitoring device.

[0121] Step 3: Calculate the SF6 concentration based on the corrected true phase difference;

[0122] In a preferred but non-limiting embodiment of the present invention, step 3 specifically includes:

[0123] Based on the corrected true phase difference Δφ, and combined with the dual-chamber acoustic path L (the acoustic path between the background gas chamber and the measured gas chamber is the same, unit: m), the SF6 concentration is estimated. (unit:%):

[0124] ;

[0125] in The center frequency of the ultrasonic wave (unit: Hz, determined by the parameters of the ultrasonic transducer module, usually taken as 40kHz). This is the coupling coefficient between the phase difference and the sound path, used to convert the corrected true phase difference into a concentration ratio.

[0126] Step 4: Verify and output the calculated SF6 concentration data.

[0127] In a preferred but non-limiting embodiment of the present invention, step 4 specifically includes:

[0128] The CPLD signal processing module will calculate the SF6 concentration. The data is transmitted to the ARM module, which then combines the actual oxygen concentration data collected and transmitted from the oxygen sensor. (Used to eliminate the influence of abnormal air composition on the gas mixture, unit: %) Secondary verification: If the actual oxygen concentration data The deviation is 21% ± 1%, which is the actual oxygen concentration data. If it is not within the 21%±1% range, then it should be corrected using the following formula. And obtain the corrected SF6 concentration :

[0129] ;

[0130] in The oxygen concentration in standard air is 21%.

[0131] Next, the final corrected SF6 concentration will be... The data is transmitted via the ARM module to a PC connected to the ARM module, and the SF6 concentration is displayed in real time on the PC. .

[0132] The beneficial effects of the present invention are as follows: Compared with the prior art, the technical effects of the present invention include:

[0133] Eliminating multi-parameter system errors: By introducing air pressure sensors and humidity sensors, a multi-parameter compensation model is established, and the influence of air pressure and humidity on ultrasonic propagation speed is quantified into compensation coefficients, reducing the SF6 concentration detection error from the existing ±5%~±8% to within ±2%, meeting the high-precision monitoring needs of the power industry.

[0134] Improved environmental adaptability: The compensation model covers a temperature range of 0℃ to 60℃, an air pressure range of 80kPa to 120kPa, and a humidity range of 20%RH to 80%RH, which can adapt to the field environment of GIS substations in different regions and seasons, and solve the problem of the sharp drop in accuracy of traditional devices in complex environments.

[0135] Enhanced detection reliability: By combining secondary verification of oxygen concentration, interference from abnormal air composition (such as hypoxia or hyperxia) on the detection of mixed gases is eliminated, further ensuring the authenticity of the concentration estimation results;

[0136] High compatibility: No need to change the dual-chamber and CPLD / ARM hardware architecture of the existing detection device. Only the addition of air pressure and humidity sensors and the upgrading of the algorithm are required. It can be directly applied to the modification of existing SF6 leak detection sensors, reducing the cost of technology promotion.

[0137] An online monitoring device based on ultrasonic quantitative detection of SF6 gas leaks is called an SF6 leak detection sensor.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention without departing from the spirit and scope of the present invention. Any modifications or equivalent substitutions should be covered within the protection scope of the claims of the present invention.

Claims

1. A gas chamber adjustment method using an SF6 leak detection sensor, characterized in that, An online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound is applied, comprising: Step 1: Parameter acquisition for the online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound; Step 2: Construction of a multi-parameter compensation model for the online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound; Step 3: Calculation of SF6 concentration based on the corrected true phase difference; Step 4: Data verification and output based on the calculated SF6 concentration; Step 2 specifically includes: Step 2-1: Correction of ultrasonic propagation speed by combining gas component correction factor, temperature and parameter synergy coefficient, and nonlinear compensation term; Step 2-2: Compensation correction of phase difference based on the corrected ultrasonic propagation speed; Step 2-1 specifically includes: Step 2-1-1: Calculation of ultrasonic propagation speed under standard operating conditions; Step 2-1-2: Correction of ultrasonic propagation speed under actual operating conditions; Step 2-1-2 specifically includes: Execution of the following multi-dimensional coupled correction formula: ;in This is the corrected ultrasonic propagation speed under actual working conditions; The speed of ultrasonic wave propagation under standard operating conditions; This is actual air pressure data; The air pressure is the standard operating pressure. This is actual humidity data; Humidity under standard operating conditions; This is actual temperature data; This is the pressure linearity correction factor; This is the pressure nonlinearity correction coefficient; This is the humidity baseline correction factor; The temperature and parameter compatibility coefficient; For gas component correction factors; For nonlinear compensation terms; Step 4 specifically includes: the CPLD signal processing module calculating the SF6 concentration The data is transmitted to the ARM module, which then combines the actual oxygen concentration data collected and transmitted from the oxygen sensor. ,right Secondary verification: If the actual oxygen concentration data If the deviation is 21% ± 1%, it will be corrected using the following formula. And obtain the corrected SF6 concentration ： ;in The standard air oxygen concentration is 21%; then the final corrected SF6 concentration is... The data is transmitted via the ARM module to a PC connected to the ARM module, and the SF6 concentration is displayed in real time on the PC. 。 2. The gas chamber adjustment method using an SF6 leak detection sensor according to claim 1, characterized in that, Step 1 specifically includes: Step 1-1: Add a pressure sensor and a humidity sensor to the outside of the gas chamber of the online monitoring device for quantitative detection of SF6 gas leakage based on ultrasound. The pressure sensor and humidity sensor are connected to the ARM module together with the temperature sensor and oxygen sensor of the online monitoring device; Step 1-2: When the detection is started, the ARM module of the online monitoring device receives the synchronously acquired field environmental parameters and transmits the field environmental parameters to the CPLD signal processing module. The field environmental parameters include temperature T, air pressure P, and relative humidity RH data that are synchronously acquired and transmitted to the ARM module by the temperature sensor, pressure sensor, and humidity sensor, respectively; Step 1-3: The ultrasonic transducer module of the online monitoring device emits an ultrasonic signal S1 to the background gas chamber and an ultrasonic signal S2 to the gas chamber being tested, according to the existing dual-chamber detection logic. The CPLD signal processing module receives the echoes of the two ultrasonic signals and calculates the phase difference as the original phase difference Δφ0.

3. The gas chamber adjustment method using an SF6 leak detection sensor according to claim 2, characterized in that, In step 2-1-1, the formula for calculating the ultrasonic propagation speed under standard operating conditions is: ;in The speed of ultrasonic wave propagation under standard operating conditions; This refers to the specific heat ratio of the gas. The gas constant is... The temperature is the standard operating temperature. The gas molar mass; in step 2-1-1, the gas pressure under standard operating conditions. =101.325kPa, humidity under standard operating conditions =50%; when the gas is air in the background gas chamber under standard operating conditions. =1.4, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. =1.06; when the gas is air in the background gas chamber under standard operating conditions, =287 J / (kg・K), when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. =65.7J / (kg・K)); Including the speed of ultrasonic wave propagation in a background gas chamber under standard operating conditions. The ultrasonic propagation speed in a background gas chamber containing a mixture of SF6 and air under standard operating conditions. 。 4. The gas chamber adjustment method using an SF6 leak detection sensor according to claim 3, characterized in that, In step 2-1-2, when the gas is air from the background gas chamber under standard operating conditions, The value is 0.85, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. The value is 0.62; The value is -0.12; when the gas is air in the background gas chamber under standard operating conditions, The value is 0.08, when the gas is a mixture of SF6 and air in the background gas chamber under standard operating conditions. The value is 0.11; ,in ； ,in This is actual oxygen concentration data; The oxygen concentration in standard air is 21%. Including the ultrasonic propagation speed when the gas is air in the background gas chamber under actual operating conditions. The ultrasonic propagation speed in a background gas chamber containing a mixture of SF6 and air under actual operating conditions. 。 5. The gas chamber adjustment method using an SF6 leak detection sensor according to claim 4, characterized in that, Step 2-2 specifically includes: the original phase difference Δφ0 is corrected to the true phase difference Δφ using the following formula from the multi-parameter compensation model: ;in The speed of ultrasonic wave propagation is given by the gas being air in a background gas chamber under standard operating conditions. The ultrasonic wave propagation speed is given by the standard operating condition of a mixture of SF6 and air in a background gas chamber. The speed of ultrasonic wave propagation is given when the gas is air in the background gas chamber under actual working conditions. The ultrasonic propagation speed is given by the background gas chamber containing a mixture of SF6 and air under actual operating conditions.

6. The gas chamber adjustment method using an SF6 leak detection sensor according to claim 5, characterized in that, Step 3 specifically includes: calculating the SF6 concentration based on the corrected true phase difference Δφ and the dual-chamber acoustic path L. ： ;in The center frequency of the ultrasound. This is the coupling coefficient between the phase difference and the sound path, used to convert the corrected true phase difference into a concentration ratio.

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