Three-point array type temperature measuring device and method for detecting temperature of contact of vacuum arc-extinguishing chamber of environment-friendly switch

Abstract

The invention belongs to the technical field of arc extinguish chamber contact temperature prediction, particularly relates to a three-point array type temperature measuring device and method for environment-friendly switch vacuum arc extinguish chamber contact temperature detection, and provides a set of complete environment-friendly switch vacuum arc extinguish chamber internal contact temperature non-contact infrared temperature measuring device. Comprising a three-point array type infrared emission module, an infrared transmission module, a temperature calibration compensation module and a contact temperature inversion calculation module, a plurality of infrared temperature measurement points form a cooperative measurement array with a fixed space relation, and the temperature of key points on the outer surface of the shielding case of the vacuum arc-extinguishing chamber is measured. Inversion calculation of the temperature of the contact of the arc extinguish chamber is achieved, the technical problems that an existing indirect measurement method based on the temperature of a single point on the surface of a shell or an empirical formula is inaccurate in measurement, cannot truly reflect the thermal state of the internal contact and the like are solved, and the method has great significance in mastering the temperature rise condition of environment-friendly switch equipment and guaranteeing safe operation of the equipment.

Description

Technical Field

[0001] This invention relates to the field of arc-extinguishing chamber contact temperature prediction technology, specifically to a three-point array temperature measuring device and method for detecting the contact temperature of vacuum arc-extinguishing chambers in environmental protection switches. Background Technology

[0002] Environmentally friendly gas-insulated metal-enclosed switchgear (GIS) has become an important development direction in switchgear due to its excellent insulation performance and environmental friendliness. The vacuum interrupter is the core component of environmentally friendly GIS switchgear, and the operating temperature of its internal contacts is a key parameter reflecting the switch's health status and safety margin. However, since the interrupter contacts are completely sealed within a vacuum environment within a metal cavity, conventional contact-type thermocouple sensors and direct infrared irradiation sensors cannot be directly installed on the contact surface for temperature detection. Therefore, achieving accurate, non-invasive detection of the contact temperature inside the vacuum interrupter is crucial for ensuring the safe and stable operation of environmentally friendly switches.

[0003] Regarding the detection of contact temperature in GIS switchgear circuit breakers traditionally filled with sulfur hexafluoride (SF6) gas, invention patent CN114897131A, "GIS Contact Temperature Rise Monitoring Method and System Based on Deep Learning Network," proposes a method for monitoring the temperature rise of GIS contacts using a deep learning network by selecting the surface temperature of the GIS shell, the radius of the GIS cylinder, and the ambient temperature as input data. However, this method is only applicable to the temperature measurement of contacts exposed to SF6 gas. Utility model patent CN210664812U, "GIS Temperature Detection Device," installs a PCB board with a thermistor inside a connecting pipe, which is then connected to the mounting hole of the GIS equipment body to achieve temperature measurement of specific parts of the GIS equipment body. This method is also only applicable to GIS equipment filled with SF6 gas. Utility model patent CN203298870U, "GIS Equipment Contact Temperature Online Monitoring System Based on Infrared Temperature Sensor," introduces an online monitoring system suitable for the contact temperature of circuit breakers in GIS equipment filled with SF6 gas. This system uses a single-point infrared temperature sensor to detect the contact temperature, acquiring temperature information at a local point.

[0004] However, vacuum-type environmentally friendly GIS equipment differs significantly in structure from traditional GIS equipment filled with sulfur hexafluoride gas. Unlike circuit breakers exposed to sulfur hexafluoride gas, the vacuum interrupter contacts of environmentally friendly GIS equipment are completely sealed by a shielding cover. The interrupter contacts are in a vacuum environment, making it impossible to directly measure them using thermocouples or to transmit infrared rays through the metal shielding material to the contacts for temperature detection.

[0005] Therefore, there is an urgent need in this field for a temperature measuring device for detecting the contact temperature of the vacuum interrupter chamber of an environmentally friendly switch, in order to solve the problem that the internal contact temperature cannot be directly measured due to the physical barrier of the vacuum interrupter chamber shield. Summary of the Invention

[0006] In view of this, the present invention provides a three-point array temperature measuring device and method for detecting the contact temperature of vacuum interrupter chambers in environmental protection switches. The device achieves the inverse calculation of the contact temperature of the interrupter chamber by measuring the temperature of three key points on the outer surface of the shield of the vacuum interrupter chamber, so as to solve the problems of inaccurate measurement and inability to truly reflect the internal contact thermal state of existing indirect measurement methods based on single-point temperature of the shell surface or empirical formulas.

[0007] A three-point array temperature measuring device for detecting the contact temperature of the vacuum interrupter chamber of an environmentally friendly switch includes a three-point array infrared emitting array module, an infrared transmitting module, a calibration module, and a temperature inversion calculation module.

[0008] The device specifically includes the following interconnected modules: 1. Three-point array infrared emission array module: This module consists of three independent single-point long-wave infrared thermometers, which are fixedly set in a spatial triangular layout to form a cooperative measurement array with a fixed spatial relationship. This array is used to locate the temperature measurement points of objects inside the infrared medium window, realize the measurement of multiple key temperature measurement points, and provide temperature data for inverting the contact temperature.

[0009] The three thermometers are used to measure the temperatures T1, T2, and T3 at three key feature points on the outer surface of the vacuum interrupter shield, determined based on multi-physics field coupling simulation.

[0010] Furthermore, the infrared thermometer operates in the 7~14μm band and interacts with the host computer software via an RS485 communication module.

[0011] Furthermore, the three key feature points are points that are determined through electromagnetic-temperature multiphysics coupling simulation and are strongly correlated with the internal contact temperature of the vacuum interrupter.

[0012] Furthermore, the three key temperature measurement points are not collinearly distributed, forming a minimal and optimized sparse array for sensing the spatial temperature field.

[0013] 2. Infrared transmission module: In order to enable infrared radiation to penetrate the metal shield of the vacuum interrupter, the present invention designs a special infrared medium window, which is made of barium fluoride (BaF) infrared glass.

[0014] Furthermore, considering the airtightness requirements of the vacuum interrupter, the infrared medium window is designed with a flange structure, which is sealed to the interrupter shell through a sealing ring and screws, ensuring the absolute airtightness of the vacuum cavity of the interrupter while ensuring infrared measurement.

[0015] Furthermore, the barium fluoride (BaF) infrared glass has a transmittance of more than 94% in the 0.35~10μm band, enabling it to efficiently transmit long-wave infrared radiation.

[0016] 3. Temperature Calibration and Compensation Module: This module performs independent and comprehensive emissivity calibration on each infrared thermometer in the three-point array to compensate for measurement errors caused by the addition of infrared glass, the gas medium inside the chamber, and inaccuracies in the emissivity of the surface being measured. The calibration process uses the thermocouple temperature measurements at the key feature points as a reference. By adjusting the emissivity parameters of each infrared thermometer, its measured values ​​are made to be consistent with the thermocouple measurements. After comprehensive emissivity calibration and compensation adjustment, the infrared thermometer can accurately measure the temperature of the object being measured after passing through the infrared glass.

[0017] 4. Contact Temperature Inversion Calculation Module: The core of this module is a contact temperature inversion model constructed using the extreme gradient Boosting (XGBoost) machine learning algorithm. This model takes load current (I), chamber pressure (P), ambient temperature (Tenv), and the calibrated temperatures of three key feature points as input features, and the steady-state temperature (Tcontact) of the vacuum interrupter contact as the model output target. Through extensive simulation and / or experimental data forming training and testing sets, the model is trained and hyperparameters are optimized, thereby constructing a computational model that accurately describes the complex nonlinear mapping relationship between external measurable parameters and internal contact temperature, ultimately achieving precise measurement of contact temperature.

[0018] The present invention also provides a method for using the above-mentioned device for detecting the contact temperature of a vacuum interrupter chamber in an environmentally friendly switch, characterized by comprising the following steps: (1) Temperature measurement point arrangement: Based on multi-physics field coupling simulation, three key feature points are determined on the outer surface of the vacuum interrupter shield, and three single-point long-wave infrared thermometers are aligned with the three key feature points in a spatial triangle layout. (2) Infrared thermometer calibration: Thermocouples are placed at the three key feature points. Under different working conditions, the emissivity of each infrared thermometer is adjusted so that its measured value is consistent with the measured value of the thermocouple at the corresponding position, and comprehensive calibration temperature compensation is completed. (3) Data acquisition: During the operation of the environmental protection switch, the temperature, load current, ambient temperature and air chamber pressure data of the three key characteristic points after calibration are collected in real time; (4) Temperature inversion: The collected data is input into the pre-trained XGBoost machine learning model, and the XGBoost machine learning model outputs the real-time temperature of the vacuum interrupter contact.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) A three-point array temperature measuring device for detecting the contact temperature of the vacuum interrupter of an environmental protection switch systematically combines a three-point optimized array, barium fluoride transparent window, comprehensive calibration, and XGBoost intelligent inversion to achieve high-precision, non-contact online monitoring of the contact temperature of the interrupter completely sealed in a vacuum shield, thus solving the long-standing problem of direct measurement in this field.

[0020] (2) By independently calibrating and compensating each temperature measurement point, the system error is effectively eliminated, the absolute error of infrared temperature measurement is reduced, and combined with the strong fitting ability of the XGBoost algorithm, the maximum error between the final contact temperature inversion value and the simulation true value can be controlled within a small range, and the accuracy is much higher than that of traditional empirical formulas or single-point temperature measurement methods.

[0021] (3) A three-point sparse array based on simulation optimization is adopted to obtain the most effective spatial temperature field information with the fewest number of sensors. While ensuring accuracy, the system structure is simple and reliable, and the cost is far lower than that of the scheme using area array infrared thermal imager.

[0022] (4) The entire device is a non-contact measurement device, requiring no equipment to be installed on the high-voltage conductor, and does not damage the original vacuum sealing structure and insulation performance of the arc-extinguishing chamber. The flange-type infrared window design ensures the safety of the device itself. This device can be pre-installed on new equipment and is also particularly suitable for upgrading and retrofitting existing equipment, making it highly valuable for widespread application.

[0023] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a flowchart illustrating the implementation of the temperature measuring device of the present invention; Figure 2 This is a schematic diagram of the temperature measuring device of the present invention; Figure 3 This is a schematic diagram showing the selection of key temperature measurement points on the outside of the vacuum interrupter. Figure 4 (a) is the design drawing of the flange infrared window. Figure 4 (b) is the actual infrared window of the flange; Figure 5 This is a comparison chart of thermocouple temperature readings and infrared temperature readings at key temperature measurement points (T1, T2, T3) under different operating conditions before comprehensive compensation. Figure 6 This is a comparison chart of thermocouple temperature readings and infrared temperature readings at key temperature measurement points (T1, T2, T3) under different operating conditions after comprehensive compensation. Figure 7 This is a schematic diagram of the XGBoost algorithm principle; Figure 8 This is a schematic diagram of a measurement based on a three-point infrared temperature measurement array; Figure 9 This is a comparison chart of non-contact temperature measurement values ​​and multiphysics simulation calculation values. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0028] This invention provides a three-point array temperature measuring device for detecting the contact temperature of the vacuum interrupter chamber of an environmentally friendly switch, as described below in conjunction with the appendix. Figure 1-9 The present invention will be described in further detail below.

[0029] This invention focuses on the vacuum interrupter chamber of a 252kV environmentally friendly switch, and constructs a non-contact infrared temperature sensing device comprising an infrared emitting array module, an infrared transmitting module, and a temperature calibration and compensation module. A schematic diagram of the temperature measuring array consisting of three infrared thermometers is shown below. Figure 8 The infrared thermometer is fixed and sealed with the infrared window using a flange, and temperature data at three key points is obtained.

[0030] Figure 1 and Figure 2 This is a technical implementation process and schematic diagram of the temperature measuring device, which mainly includes the following four modules: 1. Three-point array infrared emitting array module Infrared thermometry utilizes the radiative thermal effect to measure temperature, solving problems such as high-voltage isolation and strong magnetic field interference, and enabling online monitoring of the operating temperature of critical equipment components. Non-contact infrared thermometry, on the other hand, calculates the temperature of an object by measuring the infrared radiation energy emanating from its surface.

[0031] The infrared hardware module used in this embodiment includes an infrared thermometer array, a power supply module, and an RS485 serial communication module. The infrared thermometer array outputs the measured temperature data to the RS485 communication module, and then communicates with the host computer via the Modbus RTU serial communication protocol, displaying the temperature data in real time in the host computer software.

[0032] The infrared thermometer uses a long-wave infrared thermometer, which is fixed in position with a stainless steel locking ring. It uses a level 2 laser for aiming. The thermometer's dual lasers penetrate the infrared glass to locate the temperature measurement point of the object inside the infrared medium window. The center point of the line connecting the two lasers is the key feature point.

[0033] like Figure 3 As shown, the array consists of three single-point long-wave infrared thermometers arranged in a spatial triangular layout. The placement of each thermometer in the array is determined based on three key feature points T1, T2, and T3, which are strongly correlated with the contact temperature, as determined by multiphysics coupling simulation calculations. These three key temperature measurement points are not collinearly distributed, forming a minimal, optimized sparse array for spatial temperature field sensing. The technical parameters of the infrared thermometers are shown in Table 1.

[0034] The RS485 communication module, based on RS485 communication bus technology, enables data transmission between the infrared thermometer and the host computer software. It features strong anti-interference capabilities, high transmission speed, and long communication distance (up to thousands of meters). The RS485 communication module has four signal inputs, allowing simultaneous communication between four infrared thermometers and the PC.

[0035] Table 1 Technical parameters of infrared thermometer

[0036] 2. Infrared transmission module Because infrared light has difficulty penetrating metals, infrared dielectric windows are required. Infrared optical materials have good transmittance in the infrared band and can be used as infrared dielectric window materials, such as silicon (Si), germanium (Ge), zinc selenide (ZnSe), sodium chloride (NaCl), potassium bromide (KBr), magnesium fluoride (MgF2), zinc sulfide (ZnS), sapphire, and barium fluoride. Different infrared optical materials have different transmittance in different bands. The transmittance is related to the material's structure, i.e., the difference in its crystal lattice structure. In practical applications, parameters such as refractive index, thermal conductivity, density, hardness, and mechanical strength must be considered.

[0037] In this embodiment, the infrared glass used for the infrared medium window is made of barium fluoride. Barium fluoride infrared glass is colorless and transparent, allowing transmission of both infrared and visible light. It has a wide bandwidth of transmittance, ranging from far ultraviolet to long-wave infrared, and can provide high transmittance without the need for an anti-reflective coating. Its transmittance in the 0.35~10μm infrared band is greater than 94%. In dry environments, it can withstand ambient temperatures up to 800℃ and exhibits high resistance to high-energy radiation. Its physical properties are shown in Table 2.

[0038] Table 2 Physical properties of barium fluoride infrared glass

[0039] This embodiment designs and manufactures an infrared medium window with a flange for fixation, tightly fitting and fixing the infrared glass to the flange with a sealing ring. The flange infrared window is connected to the circuit breaker housing through a sealing element and screws to ensure the airtightness of the circuit breaker chamber when the infrared medium window is connected to the vacuum circuit breaker chamber housing.

[0040] Design drawings and physical samples of the flange infrared media window, as shown Figure 4 As shown, the placement of the infrared medium window can be flexibly adjusted according to the voltage level of the arc-extinguishing chamber.

[0041] 3. Temperature calibration and compensation module Considering the impact of factors such as the infrared radiation loss caused by the addition of infrared glass, the clean air medium (a mixture of nitrogen and oxygen) in the gas chamber, and the emissivity of the object being measured, a comprehensive calibration and compensation was performed on each infrared thermometer in the three-point array. Using the thermocouple readings at key measurement points as the standard, the emissivity of each infrared thermometer was adjusted to ensure a correspondence between the infrared thermometer readings and the thermocouple readings, thus determining the emissivity set for the comprehensive calibration and compensation of the non-contact infrared thermometer.

[0042] like Figure 8 As shown, when the air chamber pressure is 0.1 MPa, the emissivity of the infrared thermometer is adjusted to 0.63, 0.7 and 0.73 at the T1, T2 and T3 temperature measurement points, respectively. After comprehensive temperature measurement calibration and compensation, the thermocouple temperature measurement value, infrared sensor temperature measurement value and multiphysics field simulation calculation value of the three key temperature measurement points under different working conditions are shown in Table 3 below.

[0043] Table 3. Results of non-contact infrared temperature measurement under different working conditions

[0044] Table 3 shows that, before comprehensive calibration and compensation, the infrared thermometers at the three key temperature measurement points had an error of less than 4.1℃ between the infrared temperature readings and the thermocouple temperature readings under a relatively small load current (<1500 A). However, as the load current increased, such as... Figure 5 As shown, the error between the infrared temperature measurement and the thermocouple temperature measurement gradually increases, with a maximum absolute error of 9.7℃. After adjusting the emissivity of the infrared thermometer and performing comprehensive temperature measurement calibration compensation, the infrared temperature measurement and the thermocouple temperature measurement are basically consistent, with a maximum absolute error of only 1.4℃. A comparison of temperature measurements before and after comprehensive calibration compensation is shown below. Figure 6 As shown, after comprehensive emissivity calibration and compensation adjustment, the temperature of the object being measured can be accurately measured after passing through the infrared glass.

[0045] 4. Vacuum interrupter contact temperature inversion calculation module The vacuum interrupter contact temperature inversion calculation module employs the Extreme Gradient Boosting (XGBoost) algorithm to correlate the quantization calculation model. A schematic diagram of this algorithm is shown below. Figure 7 As shown, its core idea is to improve the accuracy of the overall model by gradually correcting prediction errors. This involves combining multiple weak models (decision trees) into a powerful model, gradually improving the model's predictive ability, and introducing regularization terms to effectively avoid overfitting.

[0046] The XGBoost algorithm trains the model by minimizing an objective function, which is composed of a loss function. l and regularization term It consists of two parts. y i This represents the actual contact temperature, i.e., the simulated value of the contact temperature. f is the model's predicted value, i.e., the inverse calculation value of the contact temperature. k For the k-th decision tree, the expression is: (1) The XGBoost algorithm minimizes the loss function by progressively adding trees, with each step improving the prediction based on the previous step. It assumes that existing trees already exist. t -1 tree, the t The goal of each tree is to minimize the incremental loss function of equation (2): (2) The XGBoost algorithm uses second-order gradient information (i.e., the Hessian matrix) during training, enabling it to more accurately capture the curvature of the loss function, improving optimization efficiency and accelerating model convergence. The loss function is expanded using Taylor expansion (second-order approximation) in each iteration to simplify the optimization process, as shown in Equation 3: (3) in, It is the first derivative; It is the second derivative; This is a constant term and has no effect on minimization.

[0047] The simplified loss function after removing the constant term is given by equation (4): (4) The model of each tree in XGBoost can be represented by equation (5): (5) In the formula q The index function for the leaf nodes will take the input... x Mapped to leaf nodes q ( x ); w q(x) leaf node q ( x The weight of ).

[0048] The regularization term is defined in equation (6). T l This represents the number of leaf nodes; γ and λ These are regularization parameters; the former controls the tree complexity, and the latter controls the weight size. w j For the first j The weight of each leaf: (6) Substitute the tree model equation (5) and the regularization term (6) into equation (4), and apply the same leaf node (the first... j Summing the samples from (each leaf node), G j For the first j The sum of the gradients of the leaf nodes, H j For the first j The sum of the Hessian (second-order gradient) values ​​of the leaf nodes. The simplified final objective function is given by equation (7): (7) Apply equation (8) to w j Taking the derivative and setting it to 0, the optimal leaf node weights are obtained as shown in equation (8): (8) When constructing the tree, XGBoost selects the optimal split by optimizing the gain of the split point, that is, selecting the split point with the largest gain. The split gain of the tree is defined by equation (9): (9) in, and These are the sum of the gradient and Hessian of the left child node, respectively; and These are the gradients and Hessian sums of the right child node, respectively.

[0049] The algorithm takes load current, gas chamber pressure, ambient temperature, and the temperature of selected key external temperature measurement points of the vacuum interrupter as inputs, and the corresponding steady-state temperature of the vacuum interrupter contact as output. It establishes a training set and a test set for the contact temperature inversion calculation model, and uses the XGBoost algorithm for training, hyperparameter optimization, model evaluation and verification, thus constructing an environmentally friendly GIS vacuum interrupter contact temperature inversion calculation model.

[0050] To verify the practical effect of this embodiment, a comprehensive test was conducted on a 252kV environmentally friendly GIS vacuum interrupter platform. Temperature data from three key temperature measurement points under different operating conditions, along with load current, chamber pressure, and ambient temperature, were measured by an infrared temperature measurement array and input into the vacuum interrupter contact temperature inversion calculation module. The contact temperature value was calculated, and the results are as follows: Figure 9As shown, the non-contact measurement value of the vacuum interrupter contact temperature is basically consistent with the multiphysics simulation calculation value, with a maximum error of only 1.7℃. This verifies that the three-point array temperature measuring device and method provided by this invention can accurately and reliably infer the true temperature of the vacuum interrupter's internal contacts through a non-contact infrared temperature measuring device, providing an effective technical means for the intelligent operation and safety assurance of vacuum interrupter equipment.

[0051] In summary, this invention provides a complete non-contact infrared temperature measurement device for the internal contact temperature of the vacuum interrupter chamber of an environmentally friendly switch, including a three-point array infrared emitting module, an infrared transmitting module, a calibration module, and a temperature calculation module. Multiple infrared temperature measurement points are arranged into a coordinated measurement array with a fixed spatial relationship, solving the technical problem that the physical barrier of the vacuum interrupter chamber shield prevents direct measurement of the internal contact temperature. This is of great significance for understanding the temperature rise of environmentally friendly switchgear and ensuring the safe operation of the equipment.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A three-point array temperature measuring device for detecting the temperature of the contact of an environmentally friendly switch vacuum arc-extinguishing chamber, characterized in that, Comprise: Three-point array infrared temperature measurement module, including three single-point long-wave infrared temperature measurement instruments, which are fixedly arranged in a spatial triangle layout, for measuring the temperatures of three key feature points on the outer surface of the vacuum interrupter shield determined based on multi-physical field coupling simulation; Infrared transmission module, including flange-type infrared medium windows installed on the vacuum interrupter shield and corresponding to the three key feature points, the infrared medium windows being made of barium fluoride infrared glass; Temperature calibration and compensation module, for comprehensively calibrating and compensating each infrared temperature measurement instrument in the three-point array infrared temperature measurement module, adjusting the emissivity of each temperature measurement point infrared temperature measurement instrument, and making the measurement values of each infrared temperature measurement instrument consistent with the thermocouple reference measurement values of the corresponding key feature points; Contact temperature inversion calculation module, in communication connection with the three-point array infrared temperature measurement module, for receiving load current, gas chamber pressure, ambient temperature, and temperature data of the three key feature points, establishing a training set and a test set of a contact temperature inversion calculation model, and based on a pre-trained extreme gradient boosting XGBoost machine learning model, inversely calculating and outputting the stable-state temperature of the vacuum interrupter contact.

2. The three-point array temperature measuring device for detecting the temperature of the contact of the environmentally friendly switch vacuum arc-extinguishing chamber according to claim 1, characterized in that, The determination method of the key feature points is that the long-wave infrared temperature measurement instrument fixes the instrument position with a stainless steel locking ring, and two laser lines are used for aiming, and the center points of the two laser lines are the key feature points.

3. The three-point array temperature measuring device for detecting the temperature of the contact of the environmentally friendly switch vacuum arc-extinguishing chamber according to claim 1, characterized in that, The working waveband of the long-wave infrared temperature measurement instrument is 7-14 μm, and the RS485 communication module is connected with the upper computer.

4. The three-point array temperature measuring device for detecting the temperature of the contact of the environmentally friendly switch vacuum arc-extinguishing chamber according to claim 1, characterized in that, The three key feature points are points determined through electromagnetic-temperature multi-physical field coupling simulation and having strong correlation with the internal contact temperature of the vacuum interrupter, and the three points are non-collinearly distributed to form a sparse array for spatial temperature field perception.

5. The three-point array temperature measurement device for detecting the temperature of the contact of the environmentally friendly switch vacuum arc-extinguishing chamber according to claim 1, characterized in that, The flange-type infrared medium window is designed as a structure with a flange, and is in sealing connection with the circuit breaker shell through a sealing element and a screw, and realizes sealing connection with the vacuum circuit breaker gas chamber shell, for tightly fixing the infrared glass and the flange with a sealing ring.

6. The three-point array temperature measurement device for detecting the temperature of the contact of the environmentally friendly switch vacuum arc-extinguishing chamber according to claim 1, characterized in that, The transmittance of the barium fluoride infrared glass is greater than 94% in the 0.35-10 μm waveband.

7. The three-point array temperature measurement device for detecting the temperature of the contact of the environmentally friendly switch vacuum arc-extinguishing chamber according to claim 1, characterized in that, The XGBoost machine learning model takes the load current, gas chamber pressure, ambient temperature, and the temperatures of the key temperature measurement points outside the vacuum interrupter as inputs, and takes the stable-state temperature of the vacuum interrupter contact as output, for training, hyperparameter optimization, model evaluation and verification, and construction of a calculation model capable of accurately describing the complex nonlinear mapping relationship between the external measurable parameters and the internal contact temperature.

8. The three-point array temperature measurement device for detecting the temperature of the contact of the environmentally friendly switch vacuum arc-extinguishing chamber according to claim 7, characterized in that, The construction and training of the XGBoost machine learning model include the following steps: (1) A minimum objective function is established to train the model, which is L(0) composed of a loss function l and a regularization term Two parts, the expression is: wherein y i is the true value of the contact temperature, i.e. the contact temperature simulation value, is the predicted value of the model, i.e. the contact temperature inversion value, f k is the kth decision tree; (2) Determining the optimal leaf node weight: for the jth leaf node, the calculation formula of its optimal weight is: wherein, G j is the sum of the gradients of the j th leaf node, H j is the sum of the Hessian of the j th leaf node, λ is a regularization parameter controlling the weight size. (3) Calculate the split gain: when selecting the split point of the tree, determine the optimal split according to the split gain formula Gain: where, and are the sum of the gradients and Hessian of the left child, respectively; and are the sum of the gradients and Hessian of the right child, respectively, and γ is a regularization parameter that controls the complexity of the tree.

9. A method for detecting the temperature of the contact of the vacuum interrupter of the environmental-friendly switch using the device according to any one of claims 1-8, characterized in that, including the following steps: S1 temperature measurement point arrangement: based on multi-physical field coupling simulation, determine three key feature points on the outer surface of the vacuum interrupter shield, and align three single-point long-wave infrared temperature measurement instruments with the three key feature points in a spatial triangle layout; S2, infrared thermometer calibration: arranging thermocouples at the three key feature points, adjusting the emissivity of each infrared thermometer under different working conditions to make the measurement value consistent with the thermocouple measurement value at the corresponding position, and completing comprehensive calibration temperature compensation; S3, data acquisition: during the operation of the environmental protection switch, real-time acquisition of the temperature, load current, environmental temperature and gas chamber pressure data of the three key feature points after calibration; S4, temperature inversion: inputting the collected data into the pre-trained XGBoost machine learning model, and the XGBoost machine learning model outputs the real-time temperature of the vacuum arc-extinguishing chamber contact.

Images