A box-type transformer heat dissipation performance detection device

Abstract

The present application relates to the technical field of transformer detection, in particular to a box-type transformer heat dissipation performance detection device, which comprises a test transformer and a temperature setting mechanism symmetrically clamped outside the test transformer; the top end of the temperature setting mechanism is suspended with an external temperature measurement group for monitoring the surface thermal radiation distribution of the test transformer; a distributed optical fiber sensor is arranged on the side of the temperature setting mechanism for real-time monitoring of the internal winding temperature field gradient of the test transformer; and several node temperature measurement groups are arranged between the sides of the temperature setting mechanism for monitoring the surface node temperature of the test transformer. The three-dimensional temperature measurement network of the distributed optical fiber sensor, the infrared thermal imager and the thermistor is constructed to complete the synchronous monitoring of the vertical temperature gradient of the internal winding of the test transformer, the surface radiation heat field and the surface node temperature, achieve the reconstruction of the three-dimensional temperature field of the spatial layout, and the hotspot positioning accuracy is greatly improved compared with the traditional single-point temperature measurement mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transformer detection, in particular to a box-type transformer heat dissipation performance detection device. BACKGROUND

[0002] As the core equipment of the power system, the heat dissipation performance of the box-type transformer directly affects the operation safety and service life. The traditional heat dissipation performance detection relies on surface temperature point measurement or environmental air monitoring.

[0003] The patent with the application number CN201821908161.0 discloses a transformer heat dissipation performance testing device, which comprises a base, vertical adjusting mechanisms are fixed on the four corners of the bottom end outer wall of the base through bolts, an installation groove is formed on one side of the top end outer wall of the base, a driving mechanism is arranged in the installation groove, and a receiving groove is formed by the downward concave of the top end outer wall of the base. When not in use, the first connecting rod, the second connecting rod and the temperature sensor can be collected in the receiving groove, which is convenient for carrying the whole new device. By starting the driving mechanism, the temperature sensor can be rotated outside the transformer, which is convenient for measuring the heat dissipation of different positions outside the transformer.

[0004] The defect of the above-mentioned prior art is that the detection dimension is single, only the local surface and air temperature of the transformer can be obtained, and the temperature distribution of the whole internal and external space of the transformer during operation cannot be reflected, that is, the temperature measurement means is insufficient, which leads to the error of heat dissipation performance judgment. That is, the prior art cannot accurately evaluate the contribution of the box structure to the heat dissipation performance, and an detection device that can simulate real working conditions and space temperature distribution data is urgently needed. SUMMARY

[0005] In order to overcome the defects in the prior art, the purpose of the present application is to provide a box-type transformer heat dissipation performance detection device, which calculates the equivalent thermal resistance of the box heat dissipation channel by fusing three-dimensional temperature field data and heat source model; determines whether the box heat dissipation performance meets the standard through the temperature rise rate and thermal resistance gradient, so as to solve the problems in the above background.

[0006] In order to achieve the above-mentioned purpose, the present application provides a box-type transformer heat dissipation performance detection device, which comprises a temperature measurement part placed in the box, used for detecting the temperature rise during the operation of the transformer; the temperature measurement part comprises a test-type transformer and a temperature setting mechanism symmetrically clamped outside the test-type transformer, used for establishing three-dimensional temperature measurement points.

[0007] The temperature setting mechanism is composed of a pair of rotationally connected temperature sensing rods and a pair of telescopic rods, the telescopic rods are inserted and matched with the bottom ends of the temperature sensing rods, the top ends of the temperature sensing rods are suspended with external temperature measuring groups for monitoring the surface thermal radiation distribution of the test transformer, distributed optical fiber sensors are arranged on the top of the temperature sensing rods and the bottom of the telescopic rods for real-time monitoring of the internal winding temperature field gradient of the test transformer, a plurality of node temperature measuring groups are embedded at equal intervals between each pair of temperature sensing rods on the same side for monitoring the node temperature on the surface of the test transformer.

[0008] The external temperature measuring group is composed of an infrared thermal imager and a suspension bracket, the infrared thermal imager is adjusted to monitor the diagonal of the test transformer, the node temperature measuring group is composed of a clamping point strip and a plurality of thermistors, the thermistors are embedded at equal intervals on the clamping point strip, the thermistors are in contact with the surface of the test transformer to detect the local temperature, and a three-dimensional temperature field gradient analysis box is established through the temperature measuring part to analyze the heat dissipation performance of the box.

[0009] The above setting synchronously monitors the internal winding temperature gradient, surface radiation heat field and key node temperature of the transformer, constructs the spatial temperature distribution, and compared with the traditional single-point temperature measurement method, the hot spot positioning accuracy is improved, so that the structure heat dissipation performance of the box is accurately judged.

[0010] As a further improvement of the technical solution, a threaded hole is formed in the top end of the temperature sensing rod, a threaded rod is vertically arranged at one end of the suspension bracket, the threaded rod is threadedly connected with the threaded hole, a supporting cylinder is rotationally connected to the other end of the suspension bracket, and the supporting cylinder is sleeved and matched with the infrared thermal imager.

[0011] This setting can randomly adjust the positioning position and alignment angle of the infrared thermal imager according to the spatial size of the box and the specifications of the transformer, so as to monitor the temperature distribution of the transformer during operation in a large range.

[0012] As a further improvement of the technical solution, a connecting rod is vertically arranged at one side of the top of the temperature sensing rod, a pair of temperature sensing rods are rotationally connected through two connecting rods, and a bar-shaped elastic piece in inverted V shape is slidingly clamped below a pair of connecting rods.

[0013] This setting utilizes the resilience of the bar-shaped elastic piece to automatically clamp the end of the transformer by a pair of temperature sensing rods, so that the temperature sensing rod is installed conveniently and stably, and the temperature measuring equipment is supported to work.

[0014] As a further improvement of the technical solution, a plurality of sleeves are arranged on one side of the temperature sensing rod and one side of the telescopic rod, the distributed optical fiber sensor is sleeved and matched with the sleeve and penetrates into the inside of the test transformer.

[0015] This setting enables the positioning and installation of the distributed optical fiber sensor, and the temperature distribution of the internal winding of the transformer is monitored along the vertical direction.

[0016] As a further improvement of the technical solution, the bottom surface of the clamping point strip is provided with a plurality of clamping sleeves at equal intervals, the thermal resistance is sleeved with the clamping sleeve, and the clamping block is connected to the two ends of the clamping point strip. The two sides of the temperature probe rod and the telescopic rod are symmetrically provided with a plurality of pairs of clamping blocks, and the clamping block is clamped with each pair of clamping blocks on the same side.

[0017] As a further improvement of the technical solution, the clamping point strip and the clamping block are connected with an elastic member, which is used to rebound the clamping point strip to tightly adhere to the long side and short side heat sinks outside the test transformer.

[0018] The above arrangement enables a plurality of thermal resistances to be connected side by side into a whole, and quickly assembled between each pair of temperature probe rods to monitor the node temperature of the transformer heat sink.

[0019] As a further improvement of the technical solution, the infrared thermal imager synchronously acquires the winding temperature of the test transformer measured by a plurality of distributed optical fiber sensors; the theoretical surface temperature T1 of the test transformer is calculated through a heat conduction inversion model; and the emissivity parameter of the infrared thermal imager is optimized to make the measured value approach T1.

[0020] As a further improvement of the technical solution, the distributed optical fiber sensor is based on Raman scattering light time domain reflection technology, and the intensity ratio of two beams of light is measured to have an exponential relationship with temperature, thereby eliminating the influence of light source fluctuation.

[0021] As a further improvement of the technical solution, the thermal resistance constraint algorithm is improved through a heat conduction equation:

[0022]

[0023] Wherein T is temperature, t is time, and is the rate of change of the temperature field with time; α is the thermal diffusivity, is the Laplace operator, i.e. the second-order derivative in three-dimensional space, which refers to the diffusion process of heat in the material through conduction; and Q is the unit volume heat source power, which refers to the heat generated in the unit volume of the test transformer.

[0024] which refers to the fusion of the physical model and the measured data by dynamically correcting the predicted value of the model through the measured temperature of the thermal resistance;

[0025] Wherein β k is a penalty coefficient related to the accuracy of the thermal resistance;

[0026] is the measured temperature value of the kth thermal resistance, and N is the number of thermal resistances;

[0027] T(x k ,y​k , z k ) is the predicted temperature value of the model at the (x k , y k , z k ) position.

[0028] As a further improvement of the technical solution, the calculation formula of Q is:

[0029]

[0030] Where I is the current, R is the resistance, V is the volume, and the winding resistance of the test transformer increases significantly when it is overloaded.

[0031] Compared with the prior art, the beneficial effects of the present application are:

[0032] 1. The box-type transformer heat dissipation performance detection device, by constructing a three-dimensional temperature measurement network of distributed optical fiber sensors, infrared thermal imagers and thermistors, completes the synchronous monitoring of the vertical temperature gradient of the internal winding of the test transformer, the surface radiation heat field and the surface node temperature, achieves the reconstruction of the three-dimensional temperature field of the space layout, and the hotspot positioning accuracy is greatly improved compared with the traditional single-point temperature measurement method.

[0033] 2. The box-type transformer heat dissipation performance detection device, by means of the heat conduction equation dynamic constraint algorithm, adds this data constraint term to complete the deep fusion of the measured temperature data and the physical model, achieves the effect of reducing the model prediction error, realizes the functions of dynamic correction of measured temperature, model-data bidirectional coupling and accurate capture of local hot spots.

[0034] 3. The box-type transformer heat dissipation performance detection device, by means of the adjustable temperature probe rod and the modular clamping structure, completes the rapid adaptive installation of different specifications of transformers, achieves the detection capability of single equipment compatible with box type, and improves the deployment efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0035] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes and proportions of the components in the drawings are only illustrative and are used to help understand the present application, and are not specific limitations on the shapes and proportions of the components of the present application. Those skilled in the art can select various possible shapes and proportions to implement the present application according to specific circumstances under the guidance of the present application.

[0036] Figure 1 is a schematic diagram of the overall assembly structure of the present application;

[0037] Figure 2 is a schematic diagram of the temperature measurement part assembly structure of the present application;

[0038] Figure 3 is a front view of the present application Figure 2 ;

[0039] Figure 4 is a top view of the present application Figure 2 ;

[0040] Figure 5 is a schematic diagram of a temperature setting mechanism assembly structure of the present application

[0041] Figure 6 is a schematic diagram of a partial assembly structure of the present application Figure 5 ;

[0042] Figure 7 is a schematic diagram of a temperature setting mechanism assembly structure of the present application

[0043] Figure 8 is a schematic diagram of an external temperature measurement assembly structure of the present application

[0044] Figure 9 is a schematic diagram of a node temperature measurement assembly structure of the present application

[0045] The meanings of the respective reference numerals in the drawings are as follows:

[0046] 100, box; 200, temperature measurement part; 210, test type transformer; 211, long side heat sink; 212, short side heat sink;

[0047] 220, temperature setting mechanism; 221, temperature sensing rod; 2211, threaded hole; 2212, clamping block; 222, telescopic rod; 223, connecting rod; 2231, bearing sleeve; 224, strip-shaped elastic piece; 225, collar; 230, external temperature measurement group; 231, infrared thermal imager; 232, suspension bracket; 2321, threaded rod; 233, bearing cylinder; 240, distributed optical fiber sensor; 250, node temperature measurement group; 251, clamping point strip; 2511, clamping sleeve; 252, clamping block; 2521, elastic piece; 253, thermistor. DETAILED DESCRIPTION

[0048] The details of the application can be more clearly understood with reference to the drawings and the description of specific embodiments of the application. However, the specific embodiments of the application described herein are intended for the purpose of explanation only and are not intended to be limiting in any way. Any possible variations within the teachings of the application should be considered as falling within the scope of the application. The terms "mounting", "connected" should be interpreted broadly, and can be direct connection or indirect connection through an intermediate medium.

[0049] The terms "central axis", "vertical", "horizontal", "front", "back", "upper", "lower", "left", "right", "top", "bottom", "inner", "outer" and the like as used herein to indicate an orientation or positional relationship based on the orientation or position shown in the drawings, are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, the meaning of "several" is two or more, unless otherwise explicitly and specifically limited.

[0050] Please refer to Figures 1-4 As shown in the drawings, the present application provides a box-type transformer heat dissipation performance detection device, which comprises a temperature measurement part 200 placed inside a box body 100, used for detecting the temperature rise during transformer operation; since the box-type transformer forms an airflow with the outside through the ventilation openings and fans provided on the box body 100, and achieves the effect of dissipating the heat generated during the operation of the transformer, therefore, the heat dissipation performance of the box-type transformer is judged according to the temperature rise during the operation of the transformer, if the temperature rise during the operation of the transformer tends to be slow, it means that the heat dissipation channel of the box body 100 is well designed, otherwise the heat dissipation performance is poor; the temperature measurement part 200 comprises a test transformer 210 and a temperature setting mechanism 220 symmetrically clamped outside the test transformer 210, used for establishing a three-dimensional temperature measurement point; thereby the present application designs the temperature measurement part 200 to be placed in the box body 100, simulates the real working environment by placing the box body 100 under the sun, and then detects the heat dissipation performance of the box body 100 by overloading the test transformer 210; the three-dimensional temperature field gradient of the box body 100 is analyzed by the temperature measurement part 200.

[0051] As Figures 5-8 shown, the temperature setting mechanism 220 is composed of a pair of rotationally connected temperature sensing rods 221 and a pair of telescopic rods 222, the telescopic rods 222 are inserted and matched with the bottom ends of the temperature sensing rods 221, so as to adjust the temperature measurement height and adapt to the assembly of transformers of different heights; an external temperature measurement group 230 is suspended at the top end of the temperature sensing rod 221, used for monitoring the surface thermal radiation distribution of the test transformer 210; distributed optical fiber sensors 240 are arranged at the top of the temperature sensing rod 221 and the bottom of the telescopic rod 222, used for real-time monitoring of the winding temperature field gradient inside the test transformer 210; the distributed optical fiber sensor 240 is based on the Raman scattering light time domain reflection technology, and eliminates the influence of light source fluctuation by measuring the intensity ratio of two beams of light and the exponential relationship with temperature.

[0052] The external temperature measuring group 230 is composed of an infrared thermal imager 231 and a suspension bracket 232. The infrared thermal imager 231 is adjusted to monitor the opposite corners of the test transformer 210. The infrared lens focuses on the surface thermal radiation, converts the infrared radiation into an electrical signal, and then converts the electrical signal into a pseudo-color temperature distribution map. The infrared thermal imager 231 synchronously acquires the winding temperature of the test transformer 210 measured by a plurality of distributed optical fiber sensors 240. The theoretical surface temperature T1 of the test transformer 210 is calculated through a heat conduction inversion model. The emissivity parameter of the infrared thermal imager 231 is optimized to make the measured value approach T1. Online calibration is performed every 30 seconds to improve the surface temperature measurement accuracy.

[0053] Further, a threaded hole 2211 is formed in the top end of the temperature probe rod 221. One end of the suspension bracket 232 is vertically provided with a threaded rod 2321, which is threadedly connected with the threaded hole 2211, so that the suspension bracket 232 can adjust the height and horizontal rotation angle. The other end of the suspension bracket 232 is rotatably connected with a supporting cylinder 233. The supporting cylinder 233 is sleeved with the infrared thermal imager 231, so that the infrared thermal imager 231 can adjust the vertical angle to align with the opposite corners of the test transformer 210, and detect the surface thermal radiation distribution of the test transformer 210.

[0054] Further, in order to quickly clamp and assemble a pair of temperature probe rods 221 to the end of the test transformer 210 to form a modular design, the whole is put into different boxes 100 for temperature measurement, so as to reflect the heat dissipation performance of the box 100. A connecting rod 223 is vertically arranged on one side of the top of the temperature probe rod 221. A pair of temperature probe rods 221 are rotatably connected by two connecting rods 223. A strip-shaped spring piece 224 in inverted V shape is slidably connected below a pair of connecting rods 223. The strip-shaped spring piece 224 is made of spring steel and is in the shape of a bent sheet, so that it has resilience after being bent under stress. A supporting sleeve 2231 is integrally formed on the outer end bottom surface of the connecting rod 223. The two ends of the strip-shaped spring piece 224 are slidably inserted into the two supporting sleeves 2231. The length of the strip-shaped spring piece 224 is greater than the distance between the two supporting sleeves 2231, and the two ends of the strip-shaped spring piece 224 are in a rolled shape, thereby forming a limiting structure to prevent slipping. When a pair of temperature probe rods 221 are unfolded and a pair of connecting rods 223 are folded upward, the strip-shaped spring piece 224 can be bent and deformed to store elastic potential energy. When the temperature probe rods 221 are released, the strip-shaped spring piece 224 springs back to clamp the end of the test transformer 210, so that the temperature probe rods 221 are conveniently and stably installed, and the temperature measuring equipment is supported to work.

[0055] Further, a plurality of sleeves 225 are arranged on one side of the connecting rod 223 and on one side of the telescopic rod 222. The distributed optical fiber sensors 240 are sleeved with the sleeves 225 and penetrate into the inside of the test transformer 210 to detect the winding heat of the test transformer 210.

[0056] Specifically, as shown in Figure 2 and Figure 9 The same side of each pair of temperature probe rods 221 is embedded with a plurality of node temperature measuring groups 250 at equal intervals, for monitoring the surface node temperature of the test transformer 210; the node temperature measuring group 250 is composed of a clamping point strip 251 and a plurality of thermistors 253, the plurality of thermistors 253 are embedded on the clamping point strip 251 at equal intervals, the thermistors 253 are in contact with the surface of the test transformer 210 to detect the local temperature; the bottom surface of the clamping point strip 251 is provided with a plurality of clamping sleeves 2511, the thermistors 253 are sleeved with the clamping sleeves 2511, both ends of the clamping point strip 251 are connected with clamping blocks 252, a plurality of pairs of clamping blocks 2212 are symmetrically arranged on both sides of the temperature probe rods 221 and the telescopic rods 222, and the clamping blocks 252 are clamped with each pair of clamping blocks 2212 on the same side.

[0057] The clamping point strip 251 and the clamping block 252 are connected with an elastic member 2521, the elastic member 2521 is a spiral spring or a folding spring, one end of the elastic member 2521 is welded with the clamping block 252 and the other end is welded with the clamping point strip 251, for rebounding the clamping point strip 251 to tightly adhere to the long side heat sink 211 and the short side heat sink 212 of the test transformer 210, so that the plurality of thermistors 253 on the clamping point strip 251 tightly adhere to the long side heat sink 211 and the short side heat sink 212.

[0058] Further, the thermistor 253 constraint algorithm is to improve the heat conduction equation:

[0059]

[0060] Wherein T is the temperature, t is the time, is the rate of change of the temperature field with time, and is used to describe the transient heat transfer process, when the load is suddenly changed, the winding temperature rises rapidly with time;

[0061] α is the thermal diffusivity, α=k / pc, k is the thermal conductivity, p is the density, and c is the specific heat capacity; is the Laplace operator, that is, the second-order derivative of three-dimensional space, refers to the diffusion process of heat in the material through conduction, the spatial derivative part of the control equation, and determines the temperature field distribution form; for example, the heat transfer from the high temperature area of the winding to the adjacent low temperature area; Q is the unit volume heat source power, which refers to the heat generated in the unit volume of the test transformer 210;

[0062] The measured temperature dynamic correction model prediction value is obtained through 1 to N thermistors 253, the physical model and the measured data are fused, the model prediction value is forced to approach the actual measured value, the boundary condition is applied at the measuring point, the residual is minimized through the penalty term, the data constraint term is added, the measured temperature dynamic correction, the model-data two-way coupling and the local hot spot accurate capture are realized;

[0063] Wherein, beta k is a penalty coefficient related to the accuracy of the thermistor 253, beta k The value of beta is 10-100 times higher in the high-precision sensor area: sigma k is the measurement error of the thermistor, and beta k is increased by 10-100 times in the key hot spot area to enhance the constraint, and the typical value range is 10 3 ~10 6 W / (m 3 ·℃);

[0064] is the measured temperature value of the kth thermistor 253, and N is the number of thermistors 253;

[0065] T(x k ,y k ,z k ) is the predicted temperature value of the model at the position (x k ,y k ,z k ).

[0066] Further, the calculation formula of Q is:

[0067]

[0068] Wherein, I is current, R is resistance, V is volume, and the test transformer 210 is overloaded, and the winding resistance heat generation increases significantly.

[0069] The box-type transformer heat dissipation performance detection device of the application is used, the assembled temperature measuring part 200 is put into the prepared box body 100, the box body 100 is put into the sun to simulate the real working environment, the test transformer 210 is overloaded to speed up the heat production effect, and the subsequent three-dimensional temperature field gradient analysis of the box body 100 is established through the temperature measuring part 200 to analyze the heat dissipation performance of the box body 100;

[0070] Internal temperature monitoring:

[0071] A plurality of distributed optical fiber sensors 240 are distributed around the winding of the test transformer 210, based on the Raman scattering light time domain reflection technology, the winding temperature is obtained at every 0.5m interval in real time, and a vertical temperature gradient field is constructed;

[0072] Surface radiation monitoring:

[0073] Two infrared thermal imagers 231 capture the two-dimensional temperature distribution of the surface of the test transformer 210 in a diagonal layout. The thermal imagers synchronously acquire the wind speed data of the ventilation openings of the cabinet 100, quantifying the influence of airflow on heat dissipation. The optical fiber data is used to calculate the theoretical surface temperature T1 through a heat conduction inversion model, which is used to correct the infrared measurement values.

[0074] Node temperature constraint:

[0075] A number of thermistors 253 are arranged in an array close to the key nodes of the long-side heat sinks 211 and the short-side heat sinks 212. Based on the semiconductor resistance-temperature characteristics, the thermistors provide discrete point temperature data with an accuracy of ±0.1℃. The measured temperature is used as a boundary condition to inject the model through an improved heat conduction equation, achieving dynamic correction of the temperature field.

[0076] In summary, the present application combines three-dimensional temperature field data and Q=(I 2 R) / V heat source model to calculate the equivalent thermal resistance of the heat dissipation channel of the cabinet 100. When the temperature rise rate is less than 1℃ / min and the thermal resistance gradient is less than 10%, it is determined that the heat dissipation performance of the cabinet 100 meets the standard.

[0077] It should be noted that the test transformer, infrared thermal imager, distributed sensor, and thermistor are all prior art and will not be described again. The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made in accordance with the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A device for testing the heat dissipation performance of a box-type transformer, characterized in that: It includes a temperature measuring unit placed inside the enclosure to detect the temperature rise when the transformer is working; the temperature measuring unit includes a test transformer and a temperature setting mechanism symmetrically attached to the outside of the test transformer to establish three-dimensional temperature measuring points. The temperature setting mechanism consists of a pair of rotatably connected temperature probes and a pair of telescopic rods, with the telescopic rods inserted into the bottom of the temperature probes. An external temperature measuring group is suspended at the top of the temperature probes to monitor the heat radiation distribution on the surface of the test transformer. Distributed fiber optic sensors are installed at the top of the temperature probes and the bottom of the telescopic rods to monitor the temperature field gradient of the windings inside the test transformer in real time. Several node temperature measuring groups are embedded at equal intervals between each pair of temperature probes on the same side to monitor the node temperature on the surface of the test transformer. The external temperature measurement group consists of an infrared thermal imager and a suspension bracket. The infrared thermal imager is adjusted to be aimed at the diagonal part of the test transformer for monitoring. The node temperature measurement group consists of a locking strip and several thermistors. The thermistors are embedded at equal intervals on the locking strip. The thermistors contact the surface of the test transformer to detect the local temperature. The heat dissipation performance of the enclosure is analyzed by establishing a three-dimensional temperature field gradient through the temperature measurement unit. A connecting rod is vertically provided on one side of the top of the temperature probe rod. A pair of temperature probe rods are rotatably connected by two connecting rods. A strip-shaped spring piece in the shape of an inverted V is slidably engaged below the pair of connecting rods. The temperature probe rod located on one side of the connecting rod and the telescopic rod located on one side of the connecting rod are both provided with several collars. The distributed optical fiber sensor is sleeved and cooperates with the collars and penetrates into the interior of the test transformer. The bottom surface of the locking strip is provided with several sleeves at equal intervals. The thermistor is sleeved and fitted with the sleeves. The two ends of the locking strip are connected with locking blocks. Several pairs of clamping blocks are symmetrically provided on both sides of the temperature probe and the telescopic rod. The locking blocks are engaged with each pair of clamping blocks on the same side. An elastic element is connected between the locking strip and the locking block, which is used to rebound the locking strip to tightly fit the long side heat sink and the short side heat sink on the outside of the test transformer. The thermistor constraint algorithm is derived by improving the heat conduction equation: in T is temperature and t is time, referring to the rate of change of the temperature field over time; α is the thermal diffusivity. It is the Laplace operator, i.e., the second derivative in three-dimensional space, which refers to the diffusion process of heat within a material through conduction; Q is the heat source power per unit volume, which refers to the heat generated per unit volume of the test transformer; This refers to dynamically correcting the model's predicted values ​​using the measured temperatures of 1 to N thermistors, thereby achieving the fusion of the physical model and the measured data; Where β k This is a penalty factor related to the accuracy of the thermistor; Here is the measured temperature value of the kth thermistor, and N is the number of thermistors. T(x k ,y k ,z k ) is the model in (x k ,y k ,z k The predicted temperature value for the location.

2. The device for testing the heat dissipation performance of a box-type transformer according to claim 1, characterized in that: The temperature probe has a threaded hole at its top end, and a threaded rod is vertically provided at one end of the suspension bracket. The threaded rod is threadedly connected to the threaded hole. A support tube is rotatably connected to the bottom of the other end of the suspension bracket. The support tube is fitted with the infrared thermal imager.

3. The device for testing the heat dissipation performance of a box-type transformer according to claim 2, characterized in that: The infrared thermal imager simultaneously acquires the winding temperature of the test transformer measured by several distributed fiber optic sensors; the theoretical surface temperature T1 of the test transformer is calculated through a heat conduction inversion model; and the emissivity parameters of the infrared thermal imager are optimized to make the measured value approximate T1.

4. The device for testing the heat dissipation performance of a box-type transformer according to claim 3, characterized in that: The distributed optical fiber sensor is based on Raman scattering time-domain reflectometry. By measuring the exponential relationship between the intensity ratio of two beams of light and temperature, it eliminates the influence of light source fluctuations.

5. The device for testing the heat dissipation performance of a box-type transformer according to claim 4, characterized in that, The formula for calculating Q is: Where I is current, R is resistance, and V is volume, it refers to the significant increase in heat generation from the winding resistance of the test transformer when it is under overload.

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