Method and device for on-line self-checking of gas-insulated switchgear ultrasonic sensor

Abstract

The application relates to an online self-checking method and device for an ultrasonic sensor of a gas insulated switchgear, and belongs to the technical field of power equipment state monitoring. The method comprises the following steps: recording the arrival time of the same partial discharge pulse at a built-in ultrahigh frequency sensor and an external ultrasonic sensor, extracting the arrival time difference, obtaining the spatial propagation distance from the partial discharge point to the external ultrasonic sensor according to the arrival time difference; constructing a sound intensity transmission and interface reflection model to obtain a sound pressure transmission coefficient; based on the spatial propagation distance and the sound pressure transmission coefficient, a diffusion and absorption attenuation equation of spherical sound waves in viscous fluid is constructed to calculate a theoretical sound pressure; according to the actual output voltage peak value and the theoretical sound pressure, the sound-electricity conversion sensitivity of the external ultrasonic sensor is calculated to generate an online self-checking result. The method is beneficial to non-invasively evaluating the performance degradation of the ultrasonic sensor online, and significantly improves the precision and reliability of the field calibration.

Description

Technical Field

[0001] This application relates to the field of power equipment condition monitoring technology, and in particular to an online self-calibration method and device for ultrasonic sensors in gas-insulated switchgear. Background Technology

[0002] With the development of urban power grid construction, the number of high-voltage power equipment such as GIS (Gas Insulated Switchgear) and transformers is constantly increasing. Partial discharge detection is an important means of assessing their insulation status. In GIS partial discharge detection, ultrasonic (AE) sensors are widely used due to their convenient installation and accurate positioning.

[0003] However, ultrasonic sensors are typically attached to the GIS housing via a magnetic base and couplant, making their performance highly susceptible to environmental factors. Problems such as couplant drying and external mechanical vibration interference frequently occur in the field, leading to reduced sensor sensitivity or false alarms. Currently, there is a lack of effective online calibration methods in the field. Traditional methods of manually striking the sensor with a signal generator are insufficient to simulate the actual partial discharge mechanism and cannot quantitatively assess the sensor's true attenuation, resulting in low reliability of sensor calibration. Summary of the Invention

[0004] Therefore, it is necessary to provide an online self-calibration method and device for ultrasonic sensors in gas-insulated switchgear to address the aforementioned technical problems.

[0005] In a first aspect, this application provides an online self-calibration method for ultrasonic sensors in gas-insulated switchgear, comprising:

[0006] S100: Obtain the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extract the arrival time difference, and obtain the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference.

[0007] S200, based on the physical properties of the housing material of the gas-insulated switchgear and the protective film material of the external ultrasonic sensor, construct a sound intensity transmission and interface reflection model to obtain the sound pressure transmission coefficient;

[0008] S300, based on the spatial propagation distance and the sound pressure transmission coefficient, construct the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid, and calculate the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the device housing.

[0009] S400, obtain the actual output voltage peak value of the external ultrasonic sensor, and calculate the acoustic-to-electrical conversion sensitivity of the external ultrasonic sensor based on the actual output voltage peak value and the theoretical sound pressure.

[0010] Based on the acoustic-to-electrical conversion sensitivity, the S500 obtains online self-verification results.

[0011] Optionally, the step of recording the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extracting the time difference of arrival, and obtaining the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the time difference of arrival includes:

[0012] The moment when the built-in ultra-high frequency sensor receives the electromagnetic wave signal is taken as the reference zero moment;

[0013] Record the time when the external ultrasonic sensor receives the first wave signal, and calculate the time difference of arrival between the reference zero time and the time of the first wave signal. ;

[0014] Based on the sound velocity of insulating gas The spatial propagation distance from the discharge point to the external ultrasonic sensor is calculated by approximation using a formula. :

[0015] .

[0016] Optionally, the step of constructing a sound intensity transmission and interface reflection model based on the physical properties of the housing material of the gas-insulated switchgear and the protective film material of the external ultrasonic sensor, and obtaining the sound pressure transmission coefficient, includes: the acoustic impedance of the insulating gas inside the gas-insulated switchgear. and the impedance of the metal casing ;

[0017] Based on the sound pressure continuity boundary condition, the sound pressure transmission coefficient of sound waves penetrating the gas-solid interface is calculated using a formula. :

[0018] .

[0019] Optionally, the step of constructing the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid based on the spatial propagation distance and the sound pressure transmission coefficient, and calculating the theoretical sound pressure of the partial discharge ultrasonic wave reaching the surface of the device casing, includes:

[0020] Read the peak voltage of the ultra-high frequency signal using a voltage transformer. Pulse width is obtained from ultra-high frequency waveform analysis. ;

[0021] Obtain the equivalent input impedance constant of the measurement loop. Electroacoustic energy conversion coefficient obtained by calibrating the injected charge using a partial discharge tester ;

[0022] The partial discharge point at the reference radius is calculated using an algebraic equivalent formula. Initial equivalent sound pressure at the location :

[0023] ;

[0024] in The center response frequency of the external ultrasonic sensor; This refers to the standard parameter for the dynamic viscosity of insulating gases. The density of the gas;

[0025] The intrinsic sound absorption attenuation coefficient of the insulating gas is calculated using a formula. :

[0026] ;

[0027] in This refers to the actual peak output voltage of the external ultrasonic sensor.

[0028] Based on the initial equivalent sound pressure and the intrinsic sound absorption attenuation coefficient The theoretical sound pressure is calculated using a formula. :

[0029] .

[0030] Optionally, based on the actual peak output voltage and the theoretical sound pressure, the acoustic-to-electric conversion sensitivity of the external ultrasonic sensor is calculated, and an online self-verification result is generated, including:

[0031] Calculate in-situ sensitivity using the formula. :

[0032] ;

[0033] The in-situ sensitivity The in-situ sensitivity is compared with the factory-specified sensitivity. If the in-situ sensitivity is lower than the factory-specified sensitivity, the sensor is determined to be degraded and an online self-verification result containing alarm prompts is generated.

[0034] Secondly, this application also provides an online self-calibration device for ultrasonic sensors in gas-insulated switchgear, comprising:

[0035] The spatial distance acquisition module is used to acquire the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extract the arrival time difference, and acquire the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference.

[0036] The transmission coefficient calculation module is used to construct a sound intensity transmission and interface reflection model based on the physical properties of the housing material of the gas-insulated switchgear and the protective film material of the external ultrasonic sensor, and to obtain the sound pressure transmission coefficient.

[0037] The theoretical sound pressure calculation module is used to construct the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid based on the spatial propagation distance and the sound pressure transmission coefficient, and to calculate the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the equipment shell.

[0038] The self-calibration module is used to obtain the actual output voltage peak value of the external ultrasonic sensor, calculate the acoustic-to-electric conversion sensitivity of the external ultrasonic sensor based on the actual output voltage peak value and the theoretical sound pressure, and generate online self-calibration results.

[0039] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in any of the above embodiments of the online self-calibration method for ultrasonic sensors based on a UHF reference and a sound field attenuation equation.

[0040] Fourthly, this application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps in any of the above embodiments of the online self-calibration method for ultrasonic sensors based on a UHF reference and a sound field attenuation equation.

[0041] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps in any of the above embodiments of the online self-calibration method for ultrasonic sensors based on a UHF reference and a sound field attenuation equation.

[0042] The aforementioned online self-calibration method for ultrasonic sensors in gas-insulated switchgear creatively introduces a built-in ultra-high frequency (UHF) sensor as an absolute spatiotemporal and energy physical reference. This application first completes the linear conversion from voltage to sound pressure using the equipment's factory calibration coefficients; then, it derives the sound absorption attenuation coefficient from the center frequency of the field sensor and the gas pressure and temperature; finally, it calculates the acoustic-to-electrical conversion sensitivity by the ratio of the actual voltage to the theoretically reached sound pressure. This application achieves a high-precision quantitative assessment of ultrasonic sensor performance degradation, significantly improving the reliability of calibration in engineering applications. Attached Figure Description

[0043] Figure 1 This is an application environment diagram of the online self-calibration method for ultrasonic sensors in gas-insulated switchgear, as shown in one embodiment.

[0044] Figure 2This is a flowchart illustrating an online self-calibration method for an ultrasonic sensor in a gas-insulated switchgear, as shown in one embodiment.

[0045] Figure 3 This is a schematic diagram illustrating an online self-calibration scenario for an ultrasonic sensor in one embodiment.

[0046] Figure 4 This is a diagram of an online self-calibration device for an ultrasonic sensor in a gas-insulated switchgear, as shown in one embodiment.

[0047] Figure 5 This is a diagram of the internal structure of a computer device in one embodiment. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0049] The online self-calibration method for ultrasonic sensors in gas-insulated switchgear provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. Specifically, the operator uploads the synchronous monitoring data collected by the built-in UHF sensor and the external AE sensor from the field monitoring device to server 104 through terminal 102. Server 104 performs calculations based on calibration parameters and attenuation equations, and finally outputs the online self-verification result.

[0050] In one exemplary embodiment, such as Figure 2 As shown, the process includes the following steps S100 to S400. Wherein:

[0051] S100: Obtain the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extract the arrival time difference, and obtain the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference.

[0052] The moment when the built-in ultra-high frequency sensor receives the electromagnetic wave signal is taken as the reference zero moment; the moment when the external ultrasonic sensor receives the first wave signal is obtained, and the time difference of arrival between the two is calculated. .

[0053] Electromagnetic waves propagate at approximately the speed of light within the GIS cavity, and the propagation time is negligible. This is based on the preset sound speed of the insulating gas. The spatial propagation distance from the discharge point to the sensor is calculated using the following formula. :

[0054] .

[0055] S200: Obtain the acoustic impedance of the gas-insulated switchgear housing and the matching layer of the external ultrasonic sensor, construct the sound intensity transmission and interface reflection model, and obtain the sound pressure transmission coefficient.

[0056] The acoustic impedance of the insulating gas inside the gas-insulated switchgear was measured. and the acoustic impedance of the metal casing Based on the continuity theorem in mechanics, the sound pressure transmission coefficient of sound waves penetrating the gas-solid interface is calculated. :

[0057] .

[0058] S300, based on the spatial propagation distance and the sound pressure transmission coefficient, construct the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid, and calculate the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the device housing.

[0059] Read the peak voltage of the ultra-high frequency signal using a voltage transformer. Pulse width is obtained from ultra-high frequency waveform analysis. Obtain the equivalent input impedance constant of the test circuit. .

[0060] Electroacoustic energy conversion coefficient obtained by calibrating the injected charge using a standard partial discharge calibrator The discharge point at the reference radius can be calculated using the following formula. Initial equivalent sound pressure at the location :

[0061] ;

[0062] The thermal and viscous attenuation of sound waves propagating in a gas depends entirely on the gas's physical state. The center response frequency of the external ultrasonic sensor's nameplate is obtained. The current air pressure and temperature are read from the on-site pressure gauge and thermometer, and the dynamic viscosity of the insulating gas under this temperature and pressure condition is obtained by referring to the physical standard parameter table. and gas density Therefore, the intrinsic sound absorption attenuation coefficient can be derived from the formula. :

[0063] ;

[0064] Finally, the theoretical projection of spherical waves reaching sound pressure in viscous fluids was established. Attenuation equation:

[0065] .

[0066] S400: Obtain the actual peak output voltage of the external ultrasonic sensor; calculate the acoustic-to-electric conversion sensitivity of the external ultrasonic sensor based on the actual peak output voltage and the theoretical sound pressure; and generate an online self-verification result.

[0067] Obtain the actual peak output voltage read from the AE sensor side. Calculate in-situ sensitivity :

[0068] ;

[0069] S500, the in-situ sensitivity The in-situ sensitivity is compared with the factory-specified sensitivity. If the in-situ sensitivity is lower than the factory-specified sensitivity, it is determined that the sensor has deteriorated due to reasons such as deterioration of the coupling agent, and a verification alarm result is generated and pushed to the terminal.

[0070] To provide a clearer explanation of the online self-calibration method for ultrasonic sensors based on a UHF reference and sound field attenuation equation provided in this application, a specific embodiment is described below, which includes the following steps:

[0071] S1. Obtain the arrival time of the same partial discharge pulse at the built-in UHF sensor and the external ultrasonic sensor, extract the arrival time difference, and obtain the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference and the preset sound velocity of the insulating gas.

[0072] S2, obtain the first acoustic impedance of the insulating gas inside the gas-insulated switchgear and the second acoustic impedance of the metal shell, and obtain the sound pressure transmission coefficient of the sound wave penetrating the gas-solid interface according to the sound pressure continuity boundary condition.

[0073] S3 extracts the peak voltage and pulse width of the UHF signal received by the built-in UHF sensor, obtains the equivalent input impedance constant and electroacoustic energy conversion coefficient of the measurement circuit, and calculates the initial equivalent sound pressure at the reference radius of the partial discharge point.

[0074] S4. Obtain the center response frequency of the external ultrasonic sensor, the dynamic viscosity of the insulating gas, and the gas density, and calculate the intrinsic acoustic absorption attenuation coefficient of the insulating gas.

[0075] S5, based on the initial equivalent sound pressure, intrinsic sound absorption attenuation coefficient, spatial propagation distance and sound pressure transmission coefficient, constructs the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid, and calculates the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the equipment shell.

[0076] S6: Obtain the actual peak output voltage of the external ultrasonic sensor, calculate the in-situ acoustic-electric conversion sensitivity of the external ultrasonic sensor based on the actual peak output voltage and the theoretical sound pressure, and compare it with the factory nominal sensitivity to generate an online self-verification result.

[0077] For example, such as Figure 3 The image illustrates a scenario of online self-calibration of an ultrasonic sensor. Taking a 110kV GIS device operating in a substation as an example, the device is filled with an absolute pressure of... insulation Gas, ambient temperature is Known Speed ​​of sound .

[0078] First, the spatial propagation distance and sound pressure transmission coefficient are calculated. The data acquisition card records the time difference of arrival between the UHF and the first wave of the ultrasound. The propagation distance was calculated. Retrieve Down gas density Calculate the first acoustic impedance Second acoustic impedance of aluminum alloy casing The sound pressure transmission coefficient is obtained according to the formula:

[0079] ;

[0080] Secondly, the initial equivalent sound pressure and intrinsic sound absorption attenuation coefficient were calculated. The ultra-high frequency peak voltage was measured. Pulse width impedance constant Adjusting the electroacoustic conversion coefficient Calculate the reference radius Initial sound pressure at:

[0081] ;

[0082] Obtain the center frequency of the ultrasonic sensor , Dynamic viscosity Calculate the intrinsic sound absorption attenuation coefficient:

[0083] ;

[0084] Next, the theoretical sound pressure level and sensitivity are calculated using the attenuation equation. Theoretical sound pressure level:

[0085] ;

[0086] If the actual output voltage peak value is collected Then the in-situ sensitivity is:

[0087] ;

[0088] Compared to the factory-specified sensitivity The current sensitivity is only The system determined that the sensor was degraded and output an alarm, verifying the effectiveness of the method.

[0089] In this embodiment, a high-fidelity quantitative assessment of the in-situ state of the ultrasonic sensor is achieved, significantly improving the accuracy of calibration. The steps in this embodiment enable rigorous algebraic and physical equation analysis of the complex electroacoustic conversion and attenuation processes in the field. This calibration method ensures that the performance evaluation parameters are clearly and accurately sourced, effectively solving the problem of misjudgment due to "false attenuation" caused by mechanical noise and dried coupling agent in the substation, thereby improving the calibration accuracy of the sensor and the reliability of equipment monitoring.

[0090] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0091] In one exemplary embodiment, such as Figure 4 As shown, an online self-calibration device 400 for ultrasonic sensors of gas-insulated switchgear based on a UHF reference and sound field attenuation equation is provided. The device includes: a spatial distance acquisition module 410, a transmission coefficient acquisition module 420, a theoretical sound pressure calculation module 430, and a self-calibration module 440, wherein:

[0092] The spatial distance acquisition module 410 is used to acquire the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extract the arrival time difference, and obtain the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference.

[0093] The transmission coefficient acquisition module 420 is used to construct a sound intensity transmission and interface reflection model based on the physical properties of the housing material of the gas-insulated switchgear and the protective film material of the external ultrasonic sensor, and to obtain the sound pressure transmission coefficient.

[0094] The theoretical sound pressure calculation module 430 is used to construct the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid based on spatial propagation distance and sound pressure transmission coefficient, and to calculate the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the equipment shell.

[0095] The self-calibration module 440 is used to obtain the actual output voltage peak value of the external ultrasonic sensor, calculate the acoustic-to-electric conversion sensitivity of the external ultrasonic sensor based on the actual output voltage peak value and the theoretical sound pressure, and generate online self-calibration results.

[0096] In an exemplary embodiment, the spatial distance acquisition module 410 is further configured to use the time when the built-in ultra-high frequency sensor receives the electromagnetic wave signal as the reference zero time; acquire the time when the external ultrasonic sensor receives the first wave signal, calculate the arrival time difference between the reference zero time and the first wave signal time; and calculate the spatial propagation distance from the discharge point to the external ultrasonic sensor by approximating the formula according to the preset sound velocity of insulating gas.

[0097] In an exemplary embodiment, the theoretical sound pressure calculation module 430 is further configured to extract the peak voltage and pulse width of the signal received by the built-in UHF sensor from the field measurement equipment; obtain the equivalent input impedance constant of the measurement circuit and the electroacoustic energy conversion coefficient obtained by calibration using the standard partial discharge signal under factory or initial health conditions; and calculate the initial equivalent sound pressure of the partial discharge point at the reference radius using an algebraic equivalent formula.

[0098] In an exemplary embodiment, the theoretical sound pressure calculation module 430 is further configured to obtain the center response frequency of the external ultrasonic sensor; retrieve the standard parameters of the dynamic viscosity and gas density of the insulating gas based on the real-time gas pressure and temperature of the gas-insulated switchgear; calculate the intrinsic sound absorption attenuation coefficient of the insulating gas using a formula; and calculate the theoretical sound pressure based on the initial equivalent sound pressure and the intrinsic sound absorption attenuation coefficient.

[0099] In an exemplary embodiment, the self-calibration module 440 is further configured to calculate the in-situ sensitivity using a formula; compare the in-situ sensitivity with the factory-nominated sensitivity; if the in-situ sensitivity is lower than the factory-nominated sensitivity, then determine that the sensor has deteriorated and generate an online self-calibration result containing an alarm prompt.

[0100] The modules in the aforementioned ultrasonic sensor online self-calibration device 400 based on UHF reference and sound field attenuation equation can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0101] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 5 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores data. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements an online self-calibration method for ultrasonic sensors based on a UHF reference and a sound field attenuation equation.

[0102] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0103] In one exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in any of the above embodiments of the online self-calibration method for ultrasonic sensors based on a UHF reference and a sound field attenuation equation.

[0104] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps in any of the above embodiments of the online self-calibration method for ultrasonic sensors based on a UHF reference and a sound field attenuation equation.

[0105] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in any of the above embodiments of the online self-calibration method for ultrasonic sensors based on a UHF reference and a sound field attenuation equation.

[0106] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0107] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0109] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for online self-calibration of ultrasonic sensors in gas-insulated switchgear, characterized in that, The method includes: S100, record the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extract the arrival time difference, and obtain the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference. S200, based on the physical properties of the housing material of the gas-insulated switchgear and the protective film material of the external ultrasonic sensor, a sound intensity transmission and interface reflection model is constructed to obtain the sound pressure transmission coefficient. S300, based on the spatial propagation distance and the sound pressure transmission coefficient, construct the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid, and calculate the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the device housing. S400, calculate the acoustic-to-electrical conversion sensitivity of the external ultrasonic sensor based on the actual peak output voltage and the theoretical sound pressure; Based on the acoustic-to-electrical conversion sensitivity, the S500 obtains online self-verification results.

2. The method according to claim 1, characterized in that, The process of recording the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extracting the arrival time difference, and obtaining the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference includes: The moment when the built-in ultra-high frequency sensor receives the electromagnetic wave signal is taken as the reference zero moment; Record the time when the external ultrasonic sensor receives the first wave signal, and calculate the time difference of arrival between the reference zero time and the time of the first wave signal. ; Based on the sound velocity of insulating gas The spatial propagation distance from the discharge point to the external ultrasonic sensor is calculated by approximation using a formula. : 。 3. The method according to claim 1, characterized in that, Based on the physical properties of the housing material of the gas-insulated switchgear and the protective film material of the external ultrasonic sensor, a sound intensity transmission and interface reflection model is constructed to obtain the sound pressure transmission coefficient, including: the acoustic impedance of the insulating gas inside the gas-insulated switchgear. and the impedance of the metal casing ; Based on the sound pressure continuity boundary condition, the sound pressure transmission coefficient of sound waves penetrating the gas-solid interface is calculated using a formula. : 。 4. The method according to claim 1, characterized in that, The process of constructing the diffusion and absorption attenuation equations for spherical sound waves in viscous fluids based on the spatial propagation distance and the sound pressure transmission coefficient, and calculating the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the device casing, includes: Read the peak voltage of the ultra-high frequency signal using a voltage transformer. Pulse width is obtained from ultra-high frequency waveform analysis. ; Obtain the equivalent input impedance constant of the measurement loop. Electroacoustic energy conversion coefficient obtained by calibrating the injected charge using a partial discharge tester ; The partial discharge point at the reference radius is calculated using an algebraic equivalent formula. Initial equivalent sound pressure at the location : ； in The center response frequency of the external ultrasonic sensor; This refers to the standard parameter for the dynamic viscosity of insulating gases. The density of the gas; The intrinsic sound absorption attenuation coefficient of the insulating gas is calculated using a formula. : ； in This refers to the actual peak output voltage of the external ultrasonic sensor. Based on the initial equivalent sound pressure and the intrinsic sound absorption attenuation coefficient The theoretical sound pressure is calculated using a formula. : 。 5. The method according to claim 1, characterized in that, Based on the actual peak output voltage and the theoretical sound pressure, the acoustic-to-electric conversion sensitivity of the external ultrasonic sensor is calculated, and online self-calibration results are generated, including: Calculate in-situ sensitivity using the formula. : ； The in-situ sensitivity The in-situ sensitivity is compared with the factory-specified sensitivity. If the in-situ sensitivity is lower than the factory-specified sensitivity, the sensor is determined to be degraded and an online self-verification result containing alarm prompts is generated.

6. An online self-calibration device for ultrasonic sensors in gas-insulated switchgear, characterized in that, The device includes: The spatial distance acquisition module is used to acquire the arrival time of the same partial discharge pulse at the built-in ultra-high frequency sensor and the external ultrasonic sensor, extract the arrival time difference, and acquire the spatial propagation distance from the partial discharge point to the external ultrasonic sensor based on the arrival time difference. The transmission coefficient calculation module is used to construct a sound intensity transmission and interface reflection model based on the physical properties of the housing material of the gas-insulated switchgear and the protective film material of the external ultrasonic sensor, and to obtain the sound pressure transmission coefficient. The theoretical sound pressure calculation module is used to construct the diffusion and absorption attenuation equation of spherical sound waves in viscous fluid based on the spatial propagation distance and the sound pressure transmission coefficient, and to calculate the theoretical sound pressure of partial discharge ultrasonic waves reaching the surface of the equipment shell. The self-calibration module is used to obtain the actual output voltage peak value of the external ultrasonic sensor, calculate the acoustic-to-electric conversion sensitivity of the external ultrasonic sensor based on the actual output voltage peak value and the theoretical sound pressure, and generate online self-calibration results.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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