Extra-high pressure valve side sleeve copper-aluminum transition area electric connection overheating defect evaluation method

Abstract

The invention discloses an extra-high voltage valve side sleeve copper-aluminum transition area electric connection overheating defect assessment method, which comprises the following steps: acquiring the surface temperature of a field valve side sleeve in real time, extracting to obtain a surface temperature characteristic parameter, and acquiring the real-time operation current of the field valve side sleeve at the same time; inputting the surface temperature characteristic parameter and the real-time operation current into a pre-established correlation model, and calculating to obtain a defect coefficient; and mapping the real-time operation current and the defect coefficient obtained by calculation to a pre-established fault critical curve, and performing overheating defect evaluation. According to the method, the quantitative correlation between the defect coefficient and the surface temperature is established, and the fault critical criterion is combined, so that the contact finger overheating defect is accurately evaluated.

Description

Technical Field

[0001] This application relates to the field of power equipment condition monitoring technology, specifically to a method for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high voltage valve side bushing. Background Technology

[0002] The ultra-high voltage valve-side bushing is a core component of the converter transformer. Its copper-aluminum transition zone contact fingers, subjected to long-term high current, thermal expansion and contraction, and vibration, are prone to wear and corrosion, leading to increased contact resistance and potentially causing localized overheating faults. Traditional fault detection methods, such as infrared imaging, can only determine the presence of overheating but cannot quantitatively assess the degree of defect. While power outage disassembly and inspection can accurately obtain defect information, it disrupts grid stability and is inefficient and costly.

[0003] In existing technologies, the assessment of watchband contact finger defects largely relies on contact resistance measurement, but it is difficult to directly obtain the internal contact resistance data of the fingers on-site. Although some simulation models can simulate the temperature field distribution under defects, they do not establish a correlation mechanism between defect severity and surface temperature, making rapid on-site assessment impossible. Therefore, there is an urgent need for a non-contact, high-efficiency, and high-precision overheating defect assessment method to meet the on-site operation and maintenance needs of converter stations. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this application proposes a method for assessing overheating defects in the copper-aluminum transition zone of ultra-high pressure valve side bushings. This method establishes a quantitative correlation between the defect coefficient and surface temperature, and combines it with fault critical criteria to achieve accurate assessment of overheating defects in the touch fingers.

[0005] This application is achieved through the following technical solution:

[0006] A method for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high voltage valve side bushing includes:

[0007] The surface temperature of the field valve side bushing is collected in real time and the surface temperature characteristic parameters are extracted. At the same time, the real-time operating current of the field valve side bushing is obtained.

[0008] The surface temperature characteristic parameter and the real-time operating current are input into a pre-established correlation model to calculate the defect coefficient; wherein the correlation model is the coupling relationship between the defect coefficient, the operating current and the surface temperature characteristic parameter obtained by fitting simulation data, and the defect coefficient is the ratio of the resistance of the deteriorated strap finger area to the initial resistance when there is no defect.

[0009] The real-time operating current and the calculated defect coefficient are mapped to a pre-established fault critical curve for overheating defect assessment. The fault critical curve is a curve in the form of a quadratic function, which is obtained by simulation when the temperature of the hottest spot inside the bushing reaches the limit under different operating currents.

[0010] In some implementations, the process of constructing the association model includes:

[0011] Define the defect coefficient and establish a resistance model for the copper-aluminum transition zone of the UHV valve side bushing;

[0012] The coupled simulation model of electromagnetic-thermal-fluid multiphysics field based on UHV valve side bushing was used to simulate the valve side bushing under different defect states, and multiple sets of simulation data composed of defect coefficient, operating current and surface temperature characteristic parameters were obtained.

[0013] Based on multiple sets of simulation data, a correlation model for the defect coefficient, operating current and surface temperature characteristic parameters was obtained by using quadratic function fitting.

[0014] In some implementations, defining the defect coefficient and establishing the resistance model of the copper-aluminum transition zone of the UHV valve-side bushing includes:

[0015] The defect coefficient is defined as the ratio of the resistance of the deteriorated watch band contact area to the initial resistance when there is no defect; wherein, the resistance of the deteriorated watch band contact area is equal to the sum of the resistance of the copper conductive tube, the resistance of the aluminum conductive tube, and the contact resistance of the deteriorated watch band contact, and the initial resistance when there is no defect is equal to the sum of the resistance of the copper conductive tube, the resistance of the aluminum conductive tube, and the contact resistance of the defect-free watch band contact.

[0016] The copper-aluminum transition zone is simplified into a central cylindrical structure;

[0017] Based on the cylindrical resistance formula, the correlation between equivalent conductivity and defect coefficient is established, thereby obtaining the resistance model of the copper-aluminum transition zone of the UHV valve side bushing.

[0018] In some implementations, the process of acquiring multiple sets of simulation data includes:

[0019] A coupled simulation model of electromagnetic-thermal-fluid multiphysics fields based on the valve side bushing of ultra-high pressure is established. The coupled simulation model considers the coupling relationship between electromagnetic field, temperature field and flow field, wherein the electromagnetic field affects the temperature field through Joule heating, the temperature field affects the electromagnetic field through material conductivity feedback, and the flow field affects the temperature field distribution through convective heat transfer coefficient.

[0020] Input different defect coefficients, operating currents, and ambient temperatures into the coupled simulation model to simulate the bushing temperature distribution under different defect states;

[0021] The temperature difference between the highest and lowest temperature points is extracted from the bushing temperature distribution to obtain multiple sets of simulation data, including the defect coefficient, operating current, and corresponding temperature difference.

[0022] In some implementations, the process of constructing the fault critical curve includes:

[0023] Obtain the temperature limit of the current-carrying conductive tube inside the bushing from the standard;

[0024] Within a preset operating current range, multiple current nodes are sampled according to a preset current cycle;

[0025] Simulations yielded a linear function relationship between the hottest temperature and the defect coefficient at each current node.

[0026] The critical value of the defect coefficient when the temperature is the temperature limit under each current node is solved by using the linear function relationship, thereby obtaining multiple current nodes and their corresponding critical values ​​of the defect coefficient.

[0027] The critical curve of the defect was obtained by fitting using the least squares method.

[0028] In some embodiments, the real-time acquisition of the surface temperature of the valve-side bushing and the extraction of surface temperature characteristic parameters include:

[0029] Real-time acquisition of surface temperature data of the valve side sleeve, and acquisition of the highest and lowest temperature points from the acquired surface temperature data;

[0030] The temperature difference between the highest and lowest temperature points is calculated to obtain the surface temperature characteristic parameters.

[0031] In some implementations, the overheating defect assessment includes:

[0032] The real-time operating current and the calculated defect coefficient are mapped to the fault critical curve. If the calculated defect coefficient is above the fault critical curve, the bushing is determined to have an overheating fault. If the calculated defect coefficient is below the fault critical curve, the bushing is determined to be in normal condition.

[0033] Secondly, this application proposes a device for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high voltage valve-side bushing, comprising:

[0034] The acquisition unit is used to collect the surface temperature of the field valve side bushing in real time and extract the surface temperature characteristic parameters, and at the same time acquire the real-time operating current of the field valve side bushing.

[0035] The calculation unit is used to input the surface temperature characteristic parameters and real-time operating current into a pre-established correlation model; wherein the correlation model is a coupling relationship between the defect coefficient, operating current and surface temperature characteristic parameters obtained by fitting simulation data, and the defect coefficient is the ratio of the resistance of the deteriorated strap contact area to the initial resistance when there are no defects.

[0036] And an evaluation unit, used to map the real-time operating current and the calculated defect coefficient to a pre-established fault critical curve to perform overheating defect evaluation; wherein the fault critical curve is a curve in the form of a quadratic function, which is obtained by simulation when the temperature of the hottest spot inside the bushing reaches the limit under different operating currents.

[0037] Thirdly, this application proposes an electronic device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement any of the above-described defect assessment methods.

[0038] Fourthly, this application proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described defect assessment methods.

[0039] This application proposes a method for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of the UHV valve-side bushing. This method utilizes only temperature data obtained through infrared imaging and current data acquired by the converter station monitoring system to perform a non-contact, on-site assessment of overheating defects in the copper-aluminum transition zone of the UHV valve-side bushing. It eliminates the need for bushing disassembly or power outage testing, effectively avoiding disruption to the normal operation of the power grid. Furthermore, this method boasts high accuracy and adaptability, with a small fitting error in the correlation model, enabling stable adaptation to the complex and ever-changing field environment of the converter station. In addition, the method's process is simple and clear, allowing direct integration into the existing operation and maintenance system of the converter station to achieve automated defect assessment, significantly improving equipment operation and maintenance efficiency and intelligence.

[0040] Correspondingly, the overheating defect assessment device, electronic device and computer-readable storage medium for the copper-aluminum transition zone electrical connection of the ultra-high pressure valve side bushing proposed in this application also have the same technical effects as described above. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of the embodiments of this application and form part of this application, do not constitute a limitation on the embodiments of this application. In the drawings:

[0042] Figure 1 This is a flowchart of the method for assessing overheating defects in the copper-aluminum transition zone electrical connection of the UHV valve side bushing, as proposed in this application embodiment.

[0043] Figure 2 This is a schematic diagram of the overheating defect assessment device for the copper-aluminum transition zone electrical connection of the ultra-high pressure valve side bushing proposed in this application embodiment;

[0044] Figure 3 This is a schematic diagram of the architecture of the ultra-high pressure valve-side bushing copper-aluminum transition zone electrical connection overheating defect assessment system proposed in this application embodiment;

[0045] Figure 4 This is a schematic diagram of the electronic device proposed in the embodiments of this application;

[0046] Figure 5 This is a schematic diagram of a computer-readable storage medium proposed in an embodiment of this application;

[0047] Figure 6 An example of an association model constructed for embodiments of this application;

[0048] Figure 7 Example of a fault criticality curve constructed for an embodiment of this application;

[0049] Figure 8 The following is an evaluation result diagram of two valve-side bushings of a field converter station according to an embodiment of this application. (a) shows the calculation result of the defect coefficient of the two valve-side bushings, and (b) shows the location of the defect coefficient of the two valve-side bushings in the critical defect of the fault.

[0050] Figure reference numerals and corresponding component names:

[0051] 200-Defect assessment device, 201-Acquisition unit, 202-Calculation unit, 203-Evaluation unit, 300-Defect assessment system, 301-Input device, 302-Output device, 303-Processor A, 304-Memory A, 400-Electronic device, 410-Memory B, 420-Processor B, 411-Computer program A, 500-Computer-readable storage medium, 511-Computer program B. Detailed Implementation

[0052] In the following, the terms “comprising” or “may include” as used in the various embodiments of this application indicate the presence of a function, operation, or element of the invention and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in the various embodiments of this application, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0053] In various embodiments of this application, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.

[0054] The terms used in the various embodiments of this application (such as "first," "second," etc.) may modify various constituent elements in the various embodiments, but do not limit the corresponding constituent elements. For example, the above terms do not limit the order and / or importance of the elements. The above terms are only used for the purpose of distinguishing one element from other elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0055] It should be noted that if a description is made of "connecting" one component to another, then the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0056] The terminology used in the various embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0057] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this application are only for explaining this application and are not intended to limit this application.

[0058] To address the shortcomings of existing technologies, this application proposes a method for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high voltage valve-side bushing, specifically as follows: Figure 1 As shown, the defect assessment method proposed in this application includes the following steps:

[0059] Step 1: Real-time acquisition of the surface temperature of the valve side bushing and extraction of surface temperature characteristic parameters, and simultaneous acquisition of the real-time operating current of the valve side bushing.

[0060] Step 2: Input the surface temperature characteristic parameters and real-time operating current into a pre-established correlation model to calculate the defect coefficient; the correlation model is the coupling relationship between the defect coefficient, operating current and surface temperature characteristic parameters obtained by fitting simulation data.

[0061] Step 3: Map the real-time operating current and the calculated defect coefficient to the pre-established fault critical curve to perform overheating defect assessment; the fault critical curve is the critical value of the defect coefficient corresponding to the hottest spot temperature inside the bushing under different operating currents obtained by simulation and fitted into a quadratic function curve.

[0062] Furthermore, in this embodiment of the application, the process of constructing the association model includes:

[0063] Define the defect coefficient and establish a resistance model for the copper-aluminum transition zone of the UHV valve side bushing;

[0064] The coupled simulation model of electromagnetic-thermal-fluid multiphysics field based on UHV valve side bushing was used to simulate the valve side bushing under different defect states, and multiple sets of simulation data composed of defect coefficient, operating current and surface temperature characteristic parameters were obtained.

[0065] Based on multiple sets of simulation data, a correlation model between the defect coefficient, operating current and surface temperature characteristic parameters was obtained by using quadratic function fitting.

[0066] Specifically, a defect coefficient is defined, and a resistance model for the copper-aluminum transition zone of the UHV valve-side bushing is established, including:

[0067] Define the defect coefficient Resistance of the degraded watch band contact area Initial resistance when there are no defects The ratio, i.e. ;in, , The resistance of the copper conductive tube. The resistance of the aluminum conductive tube body. For defect-free watchband finger contact resistance; , This refers to the contact resistance of the watch band fingers after degradation.

[0068] The copper-aluminum transition region is simplified into a hollow cylindrical structure; the equivalent conductivity is established based on the cylindrical resistance formula. With defect coefficient The relationship is expressed by the formula: ,in, The length of the copper-aluminum transition zone. The inner diameter of the copper current-carrying conductor. Let be the outer diameter of the aluminum current-carrying conductor. Resistance and conductivity are inversely related; therefore, based on the equivalent conductivity, the resistance model of the copper-aluminum transition zone in the UHV valve-side bushing can be obtained.

[0069] Specifically, a coupled simulation model is used to perform simulations, resulting in multiple sets of simulation data, including:

[0070] A coupled simulation model of electromagnetic-thermal-fluid multiphysics fields based on the valve-side bushing of ultra-high voltage was established, with different defect coefficients input. (The preferred value range is 1-20), operating current (The preferred value range is 2000A-4000A) and ambient temperature (The preferred value range is 10℃-40℃) to simulate the casing temperature distribution under different defect conditions, and extract the temperature difference between the highest and lowest temperature points from the casing temperature distribution to obtain multiple sets of simulation data. Each set of simulation data includes the defect coefficient, operating current, and the corresponding temperature difference between the highest and lowest temperature points of the casing.

[0071] The multiphysics coupled simulation model considers the coupling relationship between electromagnetic field, temperature field, and flow field. The electromagnetic field affects the temperature field through Joule heating, and the temperature field affects the electromagnetic field through material conductivity feedback. The flow field affects the temperature field distribution through convective heat transfer coefficient. The model material parameters include an epoxy capacitor core with a thermal conductivity of 0.45 W / (m·K) and a copper conductive tube with a conductivity of 6.0 × 10⁻⁶ W / (m·K). 7 S / m, conductivity of aluminum conductive tube 3.3×10 7 S / m.

[0072] Specifically, the process of establishing the correlation model between the defect coefficient, operating current, and surface temperature characteristic parameters includes:

[0073] Based on multiple sets of simulation data, a quadratic function was used to fit the defect coefficients. Operating current With surface temperature characteristic parameters The coupling relationship yields the following association model: ,in, , , , The fitting coefficients are obtained through calibration using simulation data, and the fitting correlation coefficients are greater than or equal to 0.999.

[0074] The fitting error of the correlation model is less than or equal to 2%, and the model accuracy is verified by more than 5 different working conditions ((I=2600A,k=7), (I=2800A,k=5), etc.).

[0075] Furthermore, in this embodiment of the application, the process of constructing the fault critical curve includes:

[0076] Based on the IEC 60137 standard's limit that the temperature of the current-carrying conductor inside the bushing should not exceed 120°C, the critical defect coefficient values ​​corresponding to the hottest spot temperature inside the bushing reaching 120°C under different operating currents were obtained through simulation. Based on multiple sets of simulation data, a fault critical curve in the form of a quadratic function was fitted. ,in, , , The fitting coefficient is used. In practical applications, if the calculated defect coefficient is greater than the corresponding critical defect coefficient value, the bushing is determined to have an overheating defect (fault). Specifically, within the 2000A~4000A current range, a current node can be set every 200A. Using a coupled simulation model, the temperature of the hottest spot (i.e., the highest temperature point) at each node can be simulated. The changing linear function relationship is used to solve for the temperature at 120℃ at each node. The value, i.e. the critical value of the defect coefficient, is obtained, thus obtaining multiple current nodes and their corresponding critical values ​​of the defect coefficient. The critical curve is obtained by fitting with the least squares method.

[0077] Furthermore, in step 1 of this application embodiment, the surface temperature data of the valve-side bushing is collected by an infrared imaging device to determine the highest temperature point A (located at the outer insulating sheath of the copper-aluminum transition zone, approximately 6300mm from the grounding flange) and the lowest temperature point B (located at the outermost edge of the valve cap), and the temperature difference between the highest point A and the lowest point B is calculated. The temperature difference is used as a surface temperature characteristic parameter. The temperature measurement error of this infrared imaging device is less than or equal to 1℃. During data acquisition, the ambient temperature fluctuation must be less than or equal to 5℃, and direct sunlight on the bushing surface must be avoided. Simultaneously, the real-time operating current of the bushing is obtained through the converter station monitoring system.

[0078] Furthermore, in step 3 of this application embodiment, the overheating defect assessment specifically involves mapping the real-time operating current and the calculated defect coefficient to the fault critical curve. If the calculated defect coefficient is above the fault critical curve, it is determined that the bushing has an overheating fault; if it is below the curve, it is determined that the bushing is in normal condition.

[0079] The defect assessment method proposed in this application can perform non-contact, on-site assessment of overheating defects in the copper-aluminum transition zone of the UHV valve-side bushing using only temperature data obtained from infrared imaging and current data obtained from the converter station monitoring system. This eliminates the need to disassemble the bushing or shut down the power supply for inspection, effectively avoiding any impact on the normal operation of the power grid. Compared to the limitations of traditional infrared imaging technology, which can only qualitatively determine the presence of overheating, this method, through the coupled analysis of defect coefficients and fault critical curves, can quantitatively distinguish the degree of defects, providing accurate data support for maintenance personnel to prioritize repairs. Furthermore, this method possesses high accuracy and adaptability, with a correlation model fitting error of less than or equal to 2%, and requires no additional correction within an ambient temperature range of 10℃ to 40℃, enabling stable adaptation to the complex and ever-changing field environment of the converter station. In addition, the method has a simple and clear process, which can be directly integrated into the existing maintenance system of the converter station to achieve automated defect assessment, significantly improving equipment maintenance efficiency and intelligence.

[0080] Based on the same technical concept described above, this application also proposes a device for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high pressure valve side bushing, such as... Figure 2 As shown, the defect assessment device 200 includes:

[0081] The acquisition unit 201 is used to acquire the surface temperature of the field valve-side bushing in real time and extract the surface temperature characteristic parameters, while also acquiring the real-time operating current of the field valve-side bushing. The specific acquisition method is as described in step 1 above, and will not be repeated here.

[0082] The calculation unit 202 is used to input the surface temperature characteristic parameters and the real-time operating current into a pre-established correlation model to calculate the defect coefficient; the correlation model is the coupling relationship between the defect coefficient, the operating current and the surface temperature characteristic parameters obtained by fitting simulation data.

[0083] Furthermore, the evaluation unit 203 is used to map the real-time operating current and the calculated defect coefficient to a pre-established fault critical curve for overheating defect evaluation. This fault critical curve is a curve fitted into a quadratic function form, obtained through simulation when the temperature of the hottest spot inside the bushing reaches a limit under different operating currents. The specific evaluation process is as described in step 3 above and will not be repeated here.

[0084] The construction process of the correlation model and the fault critical curve is as described in the above method and will not be repeated here.

[0085] Based on the same technical concept described above, this application also proposes a system for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high pressure valve side bushing, such as... Figure 3 As shown, the defect assessment system 300 proposed in this application includes:

[0086] The system comprises an input device 301, an output device 302, a processor A303, and a memory A304; wherein the number of processors A303 and memory A304 can be one or more. Figure 3 The following description uses a processor A303 and a memory A304 as an example. The input device 301, output device 302, processor A303, and memory A304 can be connected via a bus or other means. Figure 3 Taking the example of a connection between China and Israel via a bus.

[0087] Specifically, by calling the operation instructions stored in memory A304, processor A303 executes the following steps:

[0088] The surface temperature of the valve side bushing is collected in real time and the surface temperature characteristic parameters are extracted. At the same time, the real-time operating current of the valve side bushing is obtained.

[0089] The surface temperature characteristic parameters and real-time operating current are input into a pre-established correlation model to calculate the defect coefficient; the correlation model is the coupling relationship between the defect coefficient, operating current and surface temperature characteristic parameters obtained by fitting simulation data;

[0090] The real-time operating current and the calculated defect coefficient are mapped to a pre-established fault critical curve for overheating defect assessment. The fault critical curve is a curve in the form of a quadratic function, which is obtained by simulation when the temperature of the hottest spot inside the bushing reaches the limit under different operating currents.

[0091] Optionally, by calling the operation instructions stored in memory A304, processor A303 is also used to execute any of the embodiments in the corresponding examples of the above-described defect assessment method.

[0092] Based on the same technical concept described above, this application also proposes an electronic device, such as... Figure 4 As shown, the electronic device 400 includes: a memory B410, a processor B420, and a computer program A411 stored in the memory B410 and executable on the processor B420. When the processor B420 executes the computer program A411, it performs the following steps:

[0093] The surface temperature of the valve side bushing is collected in real time and the surface temperature characteristic parameters are extracted. At the same time, the real-time operating current of the valve side bushing is obtained.

[0094] The surface temperature characteristic parameters and real-time operating current are input into a pre-established correlation model to calculate the defect coefficient; the correlation model is the coupling relationship between the defect coefficient, operating current and surface temperature characteristic parameters obtained by fitting simulation data;

[0095] The real-time operating current and the calculated defect coefficient are mapped to a pre-established fault critical curve for overheating defect assessment. The fault critical curve is a curve in the form of a quadratic function, which is obtained by simulation when the temperature of the hottest spot inside the bushing reaches the limit under different operating currents.

[0096] Optionally, when processor B420 executes computer program A411, it can implement any of the embodiments in the corresponding examples of the above-described defect assessment method.

[0097] It should be noted that the electronic device proposed in this application embodiment is a device used to implement the above-mentioned defect assessment method. Therefore, based on the above-mentioned defect assessment method proposed in this application embodiment, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this application embodiment. Therefore, the specific implementation method of the above-mentioned defect assessment method will not be described in detail here. Any electronic device used by those skilled in the art to implement the above-mentioned defect assessment method is within the scope of protection of this application.

[0098] Based on the same technical concept described above, embodiments of this application also propose a computer-readable storage medium, such as... Figure 5 As shown, the computer-readable storage medium 500 stores a computer program B511, which, when executed by a processor, performs the following steps:

[0099] The surface temperature of the valve side bushing is collected in real time and the surface temperature characteristic parameters are extracted. At the same time, the real-time operating current of the valve side bushing is obtained.

[0100] The surface temperature characteristic parameters and real-time operating current are input into a pre-established correlation model to calculate the defect coefficient; the correlation model is the coupling relationship between the defect coefficient, operating current and surface temperature characteristic parameters obtained by fitting simulation data;

[0101] The real-time operating current and the calculated defect coefficient are mapped to a pre-established fault critical curve for overheating defect assessment. The fault critical curve is a curve in the form of a quadratic function, which is obtained by simulation when the temperature of the hottest spot inside the bushing reaches the limit under different operating currents.

[0102] Optionally, when the computer program B511 is executed by the processor, it can implement any of the embodiments corresponding to the above-described defect assessment method.

[0103] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0104] This application embodiment takes two valve-side bushings of a field converter station as an example, and uses the defect assessment method proposed in this application embodiment for assessment, wherein the pre-constructed correlation model is as follows: Figure 6 As shown, the pre-constructed fault critical curve is as follows: Figure 7 As shown, the specific evaluation process is as follows:

[0105] The surface temperatures of the two valve-side sleeves were collected using an infrared imaging device.

[0106] Surface temperature characteristic parameters were extracted from the collected surface temperatures: With a current I of 3000A, the hottest point on the surface of valve-side sleeve A was located in the copper-aluminum transition zone at a temperature of 35.1℃, and the outermost temperature of the cap was 19.8℃. Therefore, the surface temperature characteristic parameter ΔT for sleeve A was 23.8℃. Similarly, on valve-side sleeve B, the hottest point was also located in the copper-aluminum transition zone at a temperature of 50.2℃, and the lowest temperature at the outermost temperature of the cap was 26.3℃. Therefore, the surface temperature characteristic parameter ΔT for sleeve B was 15.3℃.

[0107] By substituting the real-time operating current and surface temperature characteristic parameters into the correlation model, the defect coefficients corresponding to the two bushings are calculated, such as... Figure 8 As shown in (a).

[0108] Based on the calculated defect coefficients of the two bushings, the overheating defects of the two bushings are evaluated, and the evaluation results are as follows: Figure 8 As shown in (b).

[0109] Depend on Figure 8 It can be seen that the defect coefficient of valve-side bushing A is approximately 2.3, with the state point located below the fault critical curve. This indicates good contact in the copper-aluminum transition zone of the bushing, and the overall operating condition of the bushing is healthy. The defect coefficient of valve-side bushing B is approximately 11.8, with the state point located above the fault critical point. This indicates that the bushing is in a relatively serious fault state. Therefore, the defect assessment method proposed in this application, by establishing a quantitative correlation between the defect coefficient and surface temperature, solves the problem of accurately assessing the overheating defects of the surface band contact fingers in the copper-aluminum transition zone of UHV valve-side bushings, providing important technical support for the safe operation and maintenance of converter station equipment.

[0110] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0111] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0112] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0113] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0114] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high voltage valve side bushing, characterized in that, include: The surface temperature of the field valve side bushing is collected in real time and the surface temperature characteristic parameters are extracted. At the same time, the real-time operating current of the field valve side bushing is obtained. The surface temperature characteristic parameters and real-time operating current are input into a pre-established correlation model to calculate the defect coefficient; The correlation model is a coupling relationship between the defect coefficient, operating current and surface temperature characteristic parameters obtained by fitting simulation data. The defect coefficient is the ratio of the resistance of the deteriorated watch band contact area to the initial resistance when there are no defects. The real-time operating current and the calculated defect coefficient are mapped to a pre-established fault critical curve to perform overheating defect assessment. The fault critical curve mentioned above is a curve in the form of a quadratic function, which is obtained by simulation when the temperature of the hottest spot inside the bushing reaches the limit under different operating currents.

2. The method for assessing overheating defects in the copper-aluminum transition zone electrical connection of an ultra-high voltage valve side bushing according to claim 1, characterized in that, The process of constructing the association model includes: Define the defect coefficient and establish a resistance model for the copper-aluminum transition zone of the UHV valve side bushing; The coupled simulation model of electromagnetic-thermal-fluid multiphysics field based on UHV valve side bushing was used to simulate the valve side bushing under different defect states, and multiple sets of simulation data composed of defect coefficient, operating current and surface temperature characteristic parameters were obtained. Based on multiple sets of simulation data, a correlation model for the defect coefficient, operating current and surface temperature characteristic parameters was obtained by using quadratic function fitting.

3. The method for assessing overheating defects in the copper-aluminum transition zone electrical connection of an ultra-high voltage valve side bushing according to claim 2, characterized in that, The definition of the defect coefficient and the establishment of the resistance model for the copper-aluminum transition zone of the UHV valve side bushing include: The defect coefficient is defined as the ratio of the resistance of the deteriorated watch band contact area to the initial resistance when there is no defect; wherein, the resistance of the deteriorated watch band contact area is equal to the sum of the resistance of the copper conductive tube, the resistance of the aluminum conductive tube, and the contact resistance of the deteriorated watch band contact, and the initial resistance when there is no defect is equal to the sum of the resistance of the copper conductive tube, the resistance of the aluminum conductive tube, and the contact resistance of the defect-free watch band contact. The copper-aluminum transition zone is simplified into a central cylindrical structure; Based on the cylindrical resistance formula, the correlation between equivalent conductivity and defect coefficient is established, thereby obtaining the resistance model of the copper-aluminum transition zone of the UHV valve side bushing.

4. The method for assessing overheating defects in the copper-aluminum transition zone electrical connection of an ultra-high voltage valve side bushing according to claim 2, characterized in that, The process of acquiring multiple sets of simulation data includes: A coupled simulation model of electromagnetic-thermal-fluid multiphysics fields based on the valve side bushing of ultra-high pressure is established. The coupled simulation model considers the coupling relationship between electromagnetic field, temperature field and flow field, wherein the electromagnetic field affects the temperature field through Joule heating, the temperature field affects the electromagnetic field through material conductivity feedback, and the flow field affects the temperature field distribution through convective heat transfer coefficient. Input different defect coefficients, operating currents, and ambient temperatures into the coupled simulation model to simulate the bushing temperature distribution under different defect states; The temperature difference between the highest and lowest temperature points is extracted from the bushing temperature distribution to obtain multiple sets of simulation data, including the defect coefficient, operating current, and corresponding temperature difference.

5. A method for assessing overheating defects in the copper-aluminum transition zone electrical connection of an ultra-high pressure valve side bushing according to any one of claims 1-4, characterized in that, The process of constructing the fault critical curve includes: Obtain the temperature limit of the current-carrying conductive tube inside the bushing from the standard; Within a preset operating current range, multiple current nodes are sampled according to a preset current cycle; Simulations yielded a linear function relationship between the hottest temperature and the defect coefficient at each current node. The critical value of the defect coefficient when the temperature is the temperature limit under each current node is solved by using the linear function relationship, thereby obtaining multiple current nodes and their corresponding critical values ​​of the defect coefficient. The critical curve of the defect was obtained by fitting using the least squares method.

6. The method for assessing overheating defects in the copper-aluminum transition zone electrical connection of an ultra-high voltage valve side bushing according to claim 5, characterized in that, The real-time acquisition of the surface temperature of the valve-side bushing and the extraction of surface temperature characteristic parameters include: Real-time acquisition of surface temperature data of the valve side sleeve, and acquisition of the highest and lowest temperature points from the acquired surface temperature data; The temperature difference between the highest and lowest temperature points is calculated to obtain the surface temperature characteristic parameters.

7. The method for assessing overheating defects in the copper-aluminum transition zone electrical connection of an ultra-high voltage valve side bushing according to claim 5, characterized in that, The aforementioned assessment of overheating defects includes: The real-time operating current and the calculated defect coefficient are mapped to the fault critical curve. If the calculated defect coefficient is above the fault critical curve, the bushing is determined to have an overheating fault. If the calculated defect coefficient is below the fault critical curve, the bushing is determined to be in normal condition.

8. A device for assessing overheating defects in the electrical connection of the copper-aluminum transition zone of an ultra-high pressure valve side bushing, characterized in that... include: The acquisition unit is used to collect the surface temperature of the field valve side bushing in real time and extract the surface temperature characteristic parameters, and at the same time acquire the real-time operating current of the field valve side bushing. The calculation unit is used to input the surface temperature characteristic parameters and real-time operating current into a pre-established correlation model; The correlation model is a coupling relationship between the defect coefficient, operating current and surface temperature characteristic parameters obtained by fitting simulation data. The defect coefficient is the ratio of the resistance of the deteriorated watch band contact area to the initial resistance when there are no defects. And an evaluation unit, used to map the real-time operating current and the calculated defect coefficient to a pre-established fault critical curve to perform overheating defect evaluation; The fault critical curve mentioned above is a curve in the form of a quadratic function, which is obtained by simulation when the temperature of the hottest spot inside the bushing reaches the limit under different operating currents.

9. An electronic 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 defect assessment method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the defect assessment method according to any one of claims 1-7.

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