A method and system for improving the accuracy of temperature measurements of a transformer tank

Abstract

The present application belongs to the field of electric power, and particularly relates to a method and system for improving the temperature measurement accuracy of a transformer shell, the method comprising: setting a transformer multi-physical field numerical calculation model based on the structure of the transformer, a sensor and the structure of a heat insulation layer; performing orthogonal design on the size of the heat insulation layer; and performing heat insulation effect analysis to determine the optimal size of the heat insulation layer. The present application proposes an anti-interference suppression method of applying a heat insulation layer to the periphery of the sensor, which can effectively improve the temperature measurement accuracy of the temperature sensor and solve the problem that the temperature measurement of the transformer shell feature temperature measurement point by the thermistor temperature sensor is easily disturbed by the environment.

Description

Technical Field

[0001] The present invention belongs to the field of electric power, and in particular relates to a method and system for improving the accuracy of measuring temperature of a transformer casing. Background Art

[0002] Transformers are crucial components of power transmission and distribution networks, performing crucial tasks such as voltage conversion, energy distribution, and transfer. Their safe and stable operation is crucial for ensuring power supply reliability. Transformer winding insulation is primarily oil-paper insulation, and the insulation performance of this material is significantly affected by winding temperature. GB / T1094.7-2008 states that the aging rate of oil-paper insulation (non-thermally modified paper) is 1 at a transformer winding hotspot temperature of 98°C. Within 140°C, the hotspot temperature and aging rate of oil-paper insulation follow a 6°C rule: for every 6°C increase in hotspot temperature, the insulation aging rate doubles. To effectively monitor the thermal state of transformers, RTD temperature sensors are often placed at typical locations on the transformer casing, such as the heat sink inlet and outlet, and at the top oil temperature measurement point. This allows for real-time monitoring of the transformer's heating status during operation, promptly reporting any abnormal heating conditions and ensuring safe and stable operation.

[0003] The external heat dissipation environment of the transformer is complex, and short-term environmental interference is inevitable. It is necessary to avoid the impact of short-term external environmental factors on the temperature measurement accuracy of the characteristic temperature measurement points of the transformer shell. Summary of the Invention

[0004] In order to solve or improve the above problems, the present invention provides a method and system for improving the accuracy of transformer housing temperature measurement. The specific technical solutions are as follows:

[0005] The present invention provides a method for improving the accuracy of measuring the temperature of a transformer casing, comprising: setting a transformer multi-physical field numerical calculation model based on the transformer structure, a sensor, and a thermal insulation layer structure; performing an orthogonal design of the thermal insulation layer size; and performing a thermal insulation effect analysis to determine the optimal thermal insulation layer size.

[0006] Preferably, the transformer multi-physical field numerical calculation model includes three-dimensional models corresponding to the transformer structure, the sensor and the thermal insulation layer structure; wherein, the three-dimensional model corresponding to the transformer structure includes a transformer core, windings, internal metal structural parts and a radiator; the three-dimensional model corresponding to the thermal insulation layer structure is a square structure.

[0007] Preferably, the sensor is a patch-type platinum resistance temperature sensor, comprising a platinum wire, alumina ceramic and a metal sheath; in the three-dimensional model, the sensor is regarded as alumina ceramic with a thermal conductivity of 36 W / (m·K) and a size of 18.2×7.5×3.2 mm.

[0008] Preferably, the heat insulation layer structure is a rubber-plastic heat-insulating material, and the measured thermal conductivity value is 0.043 W / (m·K); the heat insulation layer structure is arranged on the periphery of the sensor.

[0009] Preferably, the heat insulation effect analysis to determine the optimal insulation layer size includes: analyzing, based on the size orthogonal table corresponding to the orthogonal design, the temperature field distribution near the characteristic temperature measurement point of the transformer housing under the action of a short-term local wind speed at the heat sink inlet, wherein the short-term local wind speed includes a wind force point limited to a designated area, a wind speed of 2 m / s, and a wind blowing time of 30 min;

[0010] The effect of the thermal insulation layer is characterized by the degree of decrease in the temperature at the characteristic temperature measuring point compared to the temperature under windless conditions, and the optimal size of the thermal insulation layer is determined.

[0011] Preferably, the transformer temperature fluid field is solved by the mass conservation equation, momentum conservation equation and energy conservation equation; wherein the mass conservation equation includes In the formula, is the Hamiltonian operator, The e x 、the e y 、the e z They are the unit direction vectors on the x, y, and z coordinate axes respectively, t is the time quantity, v is the fluid velocity vector, v=ue x +ve y +we z , where u, v, and w are the flow velocities of the fluid in the x, y, and z directions, respectively, and ρ is the fluid density, kg / m 3 ; The momentum conservation equation includes Where p is the fluid pressure, Pa, and f is the external force per unit volume of fluid, N / m 3 , η is the dynamic viscosity of the fluid, kg / (m·s); the energy conservation equation includes Where T is the fluid temperature, c p is the specific heat capacity of the fluid, J / (kg·K), k is the thermal conductivity of the fluid, W / (m·K), Φ is the heat source within the fluid, S h It is the part of the fluid mechanical energy converted into thermal energy under the action of fluid viscous force.

[0012] The present invention provides a system for improving the accuracy of measuring the temperature of a transformer casing, comprising: a first unit for setting a transformer multi-physical field numerical calculation model based on the transformer structure, a sensor, and a thermal insulation layer structure; a second unit for performing orthogonal design of the thermal insulation layer size; and a third unit for performing thermal insulation effect analysis to determine the optimal thermal insulation layer size.

[0013] Preferably, the transformer multi-physical field numerical calculation model includes three-dimensional models corresponding to the transformer structure, the sensor and the thermal insulation layer structure; wherein, the three-dimensional model corresponding to the transformer structure includes a transformer core, windings, internal metal structural parts and a radiator; the three-dimensional model corresponding to the thermal insulation layer structure is a square structure.

[0014] Preferably, the sensor is a patch-type platinum resistance temperature sensor, comprising a platinum wire, alumina ceramic and a metal sheath; in the three-dimensional model, the sensor is regarded as alumina ceramic with a thermal conductivity of 36 W / (m·K) and a size of 18.2×7.5×3.2 mm.

[0015] Preferably, the heat insulation layer structure is a rubber-plastic heat-insulating material, and the measured thermal conductivity value is 0.043 W / (m·K); the heat insulation layer structure is arranged on the periphery of the sensor.

[0016] Preferably, the thermal insulation effect analysis to determine the optimal insulation layer size includes: analyzing the temperature field distribution near the characteristic temperature measuring point of the transformer casing under the action of a short-term local wind speed at the heat sink inlet according to the size orthogonal table corresponding to the orthogonal design, wherein the short-term local wind speed includes a wind force point limited to a designated area, a wind speed of 2m / s, and a wind blowing time of 30min; characterizing the effect of the insulation layer by the degree of decrease in the temperature of the characteristic temperature measuring point compared to the temperature under windless conditions, and determining the optimal insulation layer size.

[0017] The beneficial effects of the present invention are: setting up a transformer multi-physical field numerical calculation model based on the transformer structure, sensor and insulation layer structure; performing orthogonal design of the insulation layer size; performing insulation effect analysis to determine the optimal insulation layer size. In order to address the problem that the temperature of the characteristic temperature measurement point of the transformer shell is easily interfered with by the environment when using a thermistor temperature sensor, an anti-interference suppression method of applying an insulation layer on the periphery of the sensor is proposed. The present invention elaborates on the method for determining the insulation layer size in detail, which can effectively improve the temperature measurement accuracy of the temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of a method for improving the accuracy of measuring temperature of a transformer housing according to the present invention;

[0019] Figure 2 is a schematic diagram of a simulation analysis model of the effect of the thermal insulation layer on the heat dissipation characteristics of a transformer according to the present invention;

[0020] Figure 3 is a schematic diagram of a transformer housing under the effect of a short-term local wind speed at the heat sink inlet according to the present invention;

[0021] Figure 4Schematic diagram of a system for improving the accuracy of transformer housing temperature measurement according to the present invention.

[0022] Description of main reference numerals:

[0023] 1-first unit, 2-second unit, 3-third unit. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0028] Existing technologies primarily focus on preprocessing transformer fluctuating load data, eliminating abnormal monitoring data due to unstable data collection equipment and manual data collection errors, rather than performing equivalent analysis of the transformer's fluctuating load data. Another goal of existing technologies is to predict transformer loads and facilitate analysis of future load trends, rather than analyzing the equivalent load characteristics of historical fluctuating load data.

[0029] In order to solve or improve the problems raised in the background, the present invention provides Figure 1 A method for improving the accuracy of transformer casing temperature measurement is shown, comprising: setting a transformer multi-physics field numerical calculation model based on the transformer structure, sensor, and thermal insulation layer structure; performing orthogonal design of the thermal insulation layer size; and performing thermal insulation effect analysis to determine the optimal thermal insulation layer size.

[0030] The existing technology mainly improves the insulation level of the sensor by placing insulating materials near the temperature sensor, or reduces the impact of the external environment on the temperature measurement accuracy by placing a heat-insulating cavity near the temperature sensor. The designed heat-insulating structure is complex and the application effect is difficult to guarantee;

[0031] The purpose of the present invention is to address the problem that the temperature of the characteristic measuring point of the transformer casing is easily interfered by the environment when using a thermistor temperature sensor. An anti-interference suppression method is proposed by applying an insulation layer on the periphery of the sensor. The present invention elaborates on the method for determining the size of the insulation layer, which can effectively improve the temperature measurement accuracy of the temperature sensor.

[0032] The principles for improving the accuracy of transformer housing temperature measurement include:

[0033] Step 1: Establish a transformer multi-physics field numerical calculation model considering the overall structure of the transformer, sensors, and insulation layer structure.

[0034] A three-dimensional simulation analysis model of the transformer temperature fluid field is established to analyze the impact of the establishment of the thermal insulation layer on the heat dissipation characteristics of the transformer. The three-dimensional model includes structures such as the transformer core, windings, internal metal structures, and radiators. At the same time, the simulation model also includes the sensor and the thermal insulation layer structure around the sensor. The thermal insulation layer is a square structure.

[0035] Establish a simulation analysis model of the effect of thermal insulation layer on transformer heat dissipation characteristics. Figure 2 As shown in the figure, the platinum resistance temperature sensor is mainly composed of a platinum wire, alumina ceramic, and a metal sheath. Because the platinum wire and metal sheath are very thin, the entire sensor can be regarded as alumina ceramic in the temperature field simulation. Its thermal conductivity is 36W / (m·K). The size of the patch platinum resistance temperature sensor probe is 18.2×7.5×3.2mm. The designed thermal insulation layer has the dimensions of a×b×c mm in length, width, and height. The thermal insulation layer uses rubber and plastic insulation materials commonly used in engineering as the insulation layer. Its measured thermal conductivity is 0.043W / (m·K).

[0036] 步骤2,隔热层尺寸正交设计

[0037] In order to analyze the influence of the insulation layer size parameters on the insulation effect, an orthogonal design was performed with the insulation layer size as the influencing factor. The insulation layer size of the temperature sensor is a×b×c mm in length, width and height. When designing the insulation layer, the factors considered, the corresponding factor levels, and the established orthogonal table are shown in Tables 1 and 2.

[0038] 表1隔热层各因素和水平

[0039]

[0040] 表2 3因素3水平正交表

[0041]

[0042] Step 3: Analyze the thermal insulation effect and determine the optimal insulation layer size

[0043] like Figure 3 As shown in the figure, combined with the designed orthogonal table of insulation layer dimensions, the temperature field distribution near the characteristic temperature measurement point of the transformer casing is analyzed under the short-term action of local wind speed at the heat sink inlet (2m / s wind speed for 30min). The effect of the insulation layer is characterized by the degree of temperature drop at the characteristic temperature measurement point compared with the temperature under no wind conditions. The greater the degree of drop, the more seriously the insulation layer is affected by the external local wind speed.

[0044] The solution to the transformer temperature fluid field follows the three basic principles of physics: conservation of mass, conservation of momentum, and conservation of energy. The three control equations can be discretely solved using the finite volume method. The specific descriptions of the three in the Cartesian coordinate system are as follows:

[0045] Mass conservation equation (continuity equation): Where, Hamiltonian operator e x 、e y 、e z are the unit direction vectors on the x, y, and z coordinate axes respectively; t is the time quantity; v is the fluid velocity vector, v=ue x +ve y +we z , where u, v, and w are the flow velocities of the fluid in the x, y, and z directions respectively; ρ is the fluid density, kg / m 3 .

[0046] Momentum conservation equation: Where p is the fluid pressure, Pa; f is the external force per unit volume of fluid, N / m 3 ; η is the dynamic viscosity of the fluid, kg / (m·s).

[0047] Energy conservation equation: Where T is the fluid temperature; c p is the specific heat capacity of the fluid, J / (kg·K); k is the thermal conductivity of the fluid, W / (m·K); Φ is the internal heat source of the fluid; S h The part of the fluid's mechanical energy that is converted into heat energy under the action of fluid viscous force.

[0048] To effectively monitor the thermal state of a transformer, thermal resistor temperature sensors are often placed in typical areas of the transformer casing, such as the inlet and outlet of the heat sink and the oil temperature measurement location on the top layer of the transformer. This allows for real-time monitoring of the transformer's heating state during operation, promptly reflecting abnormal heating conditions and ensuring safe and stable operation. The external heat dissipation environment of the transformer is complex, and short-term environmental interference is inevitable. To prevent the impact of short-term environmental factors on the accuracy of temperature measurement at characteristic temperature measurement points on the transformer casing, existing technologies mainly improve the insulation level of the sensor by placing insulating materials near the temperature sensor, or reduce the impact of the external environment on temperature measurement accuracy by placing an insulating cavity near the temperature sensor. However, the designed insulation structure is complex and only considers the sensor itself, making the application effect difficult to guarantee. This solution proposes a three-dimensional multi-physics field simulation analysis model for the transformer that takes into account the overall structure of the transformer, the insulation layer, and the sensor structure. The orthogonal design method is used to consider the influence of the length, width, and height dimensions of the insulation layer. The insulation layer dimensions of the transformer thermal resistor temperature sensor are designed to improve the accuracy of the sensor's temperature measurement at the characteristic temperature measurement points of the transformer.

[0049] The transformer multi-physics field numerical calculation model includes three-dimensional models corresponding to the transformer structure, the sensor and the thermal insulation layer structure; wherein the three-dimensional model corresponding to the transformer structure includes a transformer core, windings, internal metal structural parts and a radiator; the three-dimensional model corresponding to the thermal insulation layer structure is a square structure.

[0050] The sensor is a patch-type platinum resistance temperature sensor, including a platinum wire, alumina ceramic and a metal sheath; in the three-dimensional model, the sensor is regarded as alumina ceramic, has a thermal conductivity of 36 W / (m·K) and dimensions of 18.2×7.5×3.2 mm.

[0051] The heat insulation layer structure is a rubber-plastic heat-insulating material, and the measured thermal conductivity value is 0.043W / (m·K); the heat insulation layer structure is arranged on the periphery of the sensor.

[0052] The thermal insulation effect analysis to determine the optimal insulation layer size includes: analyzing, based on the size orthogonal table corresponding to the orthogonal design, the temperature field distribution near the characteristic temperature measuring point of the transformer housing under the action of a short-term local wind speed at the heat sink inlet, wherein the short-term local wind speed includes a wind force point limited to a designated area, a wind speed of 2 m / s, and a wind blowing time of 30 minutes; characterizing the effect of the thermal insulation layer by the degree of decrease in the temperature at the characteristic temperature measuring point compared to the temperature under windless conditions, and determining the optimal insulation layer size.

[0053] The transformer temperature fluid field is solved by the mass conservation equation, momentum conservation equation and energy conservation equation; wherein the mass conservation equation includes In the formula, is the Hamiltonian operator, The e x 、the e y 、the e z They are the unit direction vectors on the x, y, and z coordinate axes respectively, t is the time quantity, v is the fluid velocity vector, v=ue x +ve y +we z , where u, v, and w are the flow velocities of the fluid in the x, y, and z directions, respectively, and ρ is the fluid density, kg / m 3 ; The momentum conservation equation includes Where p is the fluid pressure, Pa, and f is the external force per unit volume of fluid, N / m 3 , η is the dynamic viscosity of the fluid, kg / (m·s); the energy conservation equation includes Where T is the fluid temperature, c p is the specific heat capacity of the fluid, J / (kg·K), k is the thermal conductivity of the fluid, W / (m·K), Φ is the heat source within the fluid, S h It is the part of the fluid mechanical energy converted into thermal energy under the action of fluid viscous force.

[0054] 本发明提供如 Figure 4 A system for improving the accuracy of transformer casing temperature measurement is shown, comprising: a first unit 1 for setting a transformer multi-physics field numerical calculation model based on the transformer structure, sensor, and thermal insulation layer structure; a second unit 2 for performing orthogonal design of the thermal insulation layer size; and a third unit 3 for performing thermal insulation effect analysis to determine the optimal thermal insulation layer size.

[0055] The transformer multi-physics field numerical calculation model includes three-dimensional models corresponding to the transformer structure, the sensor and the thermal insulation layer structure; wherein the three-dimensional model corresponding to the transformer structure includes a transformer core, windings, internal metal structural parts and a radiator; the three-dimensional model corresponding to the thermal insulation layer structure is a square structure.

[0056] The sensor is a patch-type platinum resistance temperature sensor, including a platinum wire, alumina ceramic and a metal sheath; in the three-dimensional model, the sensor is regarded as alumina ceramic, has a thermal conductivity of 36 W / (m·K) and dimensions of 18.2×7.5×3.2 mm.

[0057] The heat insulation layer structure is a rubber-plastic heat-insulating material, and the measured thermal conductivity value is 0.043W / (m·K); the heat insulation layer structure is arranged on the periphery of the sensor.

[0058] The thermal insulation effect analysis to determine the optimal insulation layer size includes: analyzing, based on the size orthogonal table corresponding to the orthogonal design, the temperature field distribution near the characteristic temperature measuring point of the transformer housing under the action of a short-term local wind speed at the heat sink inlet, wherein the short-term local wind speed includes a wind force point limited to a designated area, a wind speed of 2 m / s, and a wind blowing time of 30 minutes; characterizing the effect of the thermal insulation layer by the degree of decrease in the temperature at the characteristic temperature measuring point compared to the temperature under windless conditions, and determining the optimal insulation layer size.

[0059] Those skilled in the art will appreciate that the units of the various examples described in conjunction with the embodiments disclosed in this embodiment can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0060] In the embodiments provided in the present application, it should be understood that the division of units is merely a logical function division, and there may be other division methods in actual implementation, for example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A method for improving the accuracy of transformer housing temperature measurement, characterized in that: include: Set up a transformer multi-physics field numerical calculation model based on the transformer structure, sensor and insulation layer structure; Conduct orthogonal design of insulation layer size; Conduct an insulation effectiveness analysis to determine the optimal insulation sizing, including: According to the orthogonal table of dimensions corresponding to the orthogonal design, the temperature field distribution near the characteristic temperature measurement point of the transformer housing under the action of a local short-term wind speed at the heat sink inlet is analyzed, wherein the local short-term wind speed includes a wind force point limited to a specified area, a wind speed of 2m / s, and a wind blowing time of 30min; The effect of the thermal insulation layer is characterized by the degree of decrease in the temperature at the characteristic temperature measuring point compared to the temperature under windless conditions, and the optimal size of the thermal insulation layer is determined.

2. The method for improving the accuracy of transformer housing temperature measurement according to claim 1, characterized in that: The transformer multi-physics field numerical calculation model includes three-dimensional models corresponding to the transformer structure, the sensor and the thermal insulation layer structure; The three-dimensional model corresponding to the transformer structure includes the transformer core, windings, internal metal structural parts and heat sink; The three-dimensional model corresponding to the thermal insulation layer structure is a square structure.

3. The method for improving the accuracy of transformer housing temperature measurement according to claim 2, characterized in that: The sensor is a patch-type platinum resistance temperature sensor, comprising a platinum wire, alumina ceramic and a metal sheath; In the three-dimensional model, the sensor is considered to be an alumina ceramic with a thermal conductivity of 36 W / (m·K) and a size of 18.2×7.5×3.2 mm.

4. The method for improving the accuracy of transformer housing temperature measurement according to claim 3, characterized in that: The insulation layer is made of rubber-plastic insulation material, and the measured thermal conductivity is 0.043 W / (m•K); The heat insulation layer structure is arranged on the periphery of the sensor.

5. The method for improving the accuracy of transformer housing temperature measurement according to claim 4, characterized in that: Solve the transformer temperature fluid field through the mass conservation equation, momentum conservation equation and energy conservation equation; The mass conservation equation includes , where is the Hamiltonian operator, , the e x 、the e y 、the e z are the unit direction vectors on the x, y, and z coordinate axes respectively, t is the time quantity, v is the fluid velocity vector, , where u, v, and w are the flow velocities of the fluid in the x, y, and z directions, respectively, and ρ is the fluid density, kg / m 3 ; The momentum conservation equation includes , where p is the fluid pressure, Pa, and f is the external force per unit volume of fluid, N / m 3 , η is the dynamic viscosity of the fluid, kg / (m·s); The energy conservation equation includes , where T is the fluid temperature, c p is the specific heat capacity of the fluid, J / (kg·K), k is the thermal conductivity of the fluid, W / (m·K), Φ is the internal heat source of the fluid, S h It is the part of the fluid mechanical energy converted into thermal energy under the action of fluid viscous force.

6. A system for improving the accuracy of transformer housing temperature measurement, characterized in that: include: The first unit is used to set up a transformer multi-physics field numerical calculation model based on the transformer structure, sensor and insulation layer structure; The second unit is used for orthogonal design of insulation layer size; The third unit is used to perform thermal insulation effect analysis to determine the optimal insulation layer size, including analyzing the temperature field distribution near the characteristic temperature measuring point of the transformer casing under the action of local short-term wind speed at the heat sink inlet according to the size orthogonal table corresponding to the orthogonal design, wherein the local short-term wind speed includes the wind force point limited to the designated area, the wind speed is 2m / s, and the wind blowing time is 30min; the effect of the insulation layer is characterized by the degree of temperature drop at the characteristic temperature measuring point compared to the temperature under windless conditions, and the optimal insulation layer size is determined.

7. The system for improving the accuracy of transformer housing temperature measurement according to claim 6, characterized in that: The transformer multi-physics field numerical calculation model includes three-dimensional models corresponding to the transformer structure, the sensor and the thermal insulation layer structure; The three-dimensional model corresponding to the transformer structure includes the transformer core, windings, internal metal structural parts and heat sink; The three-dimensional model corresponding to the thermal insulation layer structure is a square structure.

8. The system for improving the accuracy of transformer housing temperature measurement according to claim 7, characterized in that: The sensor is a patch-type platinum resistance temperature sensor, comprising a platinum wire, alumina ceramic and a metal sheath; In the three-dimensional model, the sensor is considered to be an alumina ceramic with a thermal conductivity of 36 W / (m·K) and a size of 18.2×7.5×3.2 mm.

9. The system for improving the accuracy of transformer housing temperature measurement according to claim 8, characterized in that: The insulation layer is made of rubber-plastic insulation material, and the measured thermal conductivity is 0.043 W / (m•K); The heat insulation layer structure is arranged on the periphery of the sensor.

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