A method and a device for determining the temperature rise of a dry-type transformer

Abstract

The application discloses a temperature rise determination method and determination device of a dry-type transformer. The temperature rise determination method of the dry-type transformer comprises the following steps: establishing a geometric model of the dry-type transformer; wherein the geometric model is determined by heat sources in the dry-type transformer; performing transient analysis on internal natural convection of the dry-type transformer according to the geometric model, and determining temperature change conditions of specific points in the dry-type transformer under different load rates; determining a transient temperature rise model of the specific points according to the change conditions, wherein the temperature rise model is a corresponding relationship model of temperature rise values of the specific points, load rates and working time; and determining the temperature rise values of the specific points in the working process of the dry-type transformer according to the transient temperature rise model, so that simulation images can be easily obtained through simulation software, and the temperature rise distribution conditions of the dry-type transformer under different load rates can be quickly obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temperature rise determination, in particular to a temperature rise determination method and determination device of a dry-type transformer. BACKGROUND

[0002] Power transformer is the core main equipment of power system, and is the key equipment of power transmission and voltage conversion. As the insulation strength and rated capacity of dry-type transformer are continuously improved, and the dry-type transformer has superior environmental performance, strong safety and reliability, and high operation efficiency, the proportion of dry-type transformer in distribution network is becoming larger and larger. In the operation process, the dry-type transformer has to bear the effects of high internal electric field stress, mechanical stress and thermal stress, etc. With the continuous expansion of power grid, the voltage level and transmission power of the dry-type transformer are gradually improved, the thermal defect problem caused by internal local overheating is increasingly serious, the temperature rise characteristics tend to be complex, and insulation aging failure is prone to occur. Therefore, in order to ensure the stable operation of the dry-type transformer, it is particularly important to study the temperature rise distribution of the dry-type transformer under the condition of natural convection heat transfer combined with the requirements of temperature rise test.

[0003] The research on temperature distribution of dry-type transformer by domestic and foreign scholars is generally based on multi-physical field coupling and fuzzy neural network algorithm to propose a transformer hot spot temperature inversion model, the finite volume method is used to solve the transformer fluid-temperature field, the temperatures of a plurality of characteristic points are selected, and the winding temperature value is predicted through the fuzzy neural network algorithm. However, when the steady-state analysis of the internal natural convection model of the dry-type transformer is carried out, the grid to be divided for the three-dimensional model is too complex, the calculation of the flow field is not easy to obtain the simulation image when the steady-state analysis is considered, and the temperature rise data of the dry-type transformer under different load rates cannot be quickly obtained due to the insufficient experimental device and experimental conditions on site. SUMMARY

[0004] The present application provides a temperature rise determination method and determination device of a dry-type transformer, which makes it easier to determine the simulation image and can quickly obtain the temperature rise distribution of the dry-type transformer under different load rates.

[0005] According to an aspect of the present application, a temperature rise determination method of a dry-type transformer is provided, which comprises:

[0006] establishing a geometric model of the dry-type transformer; wherein the geometric model is determined by a heat source in the dry-type transformer;

[0007] performing transient analysis on the internal natural convection of the dry-type transformer according to the geometric model, and determining the temperature change of a specific point in the dry-type transformer under different load rates;

[0008] According to the change, the transient temperature rise model of the specific point is determined, wherein the temperature rise model is a corresponding relationship model of the temperature rise value of the specific point, the load rate and the working time;

[0009] According to the transient temperature rise model, the temperature rise value of the specific point in the working process of the dry-type transformer is determined.

[0010] Further, the geometric model of the dry-type transformer is established, including:

[0011] According to the actual structure of the dry-type transformer, a three-dimensional model of the dry-type transformer is constructed;

[0012] According to the electromagnetic field simulation information of the three-dimensional model, the heat source position information of the dry-type transformer is determined, and the cross section of the device releasing the heat source is divided to determine the two-dimensional model of the device, and the two-dimensional model is the geometric model.

[0013] Further, according to the change, the transient temperature rise model of the specific point is determined, including:

[0014] According to the change and the preset temperature rise function, the temperature rise formula of the specific point under a plurality of different load rates is determined;

[0015] According to the temperature rise formula under a plurality of different load rates, the transient temperature rise model of the specific point is determined.

[0016] Further, the preset temperature rise function is:

[0017]

[0018] Wherein, Y is the temperature rise value, t is the working time, a is the temperature rise coefficient, and b is the time constant.

[0019] Further, according to the temperature rise formula under a plurality of different load rates, the transient temperature rise model of the specific point is determined, including:

[0020] According to the temperature rise formula under a plurality of different load rates, the second relationship between the time constant and the load rate is determined, and the first relationship between the temperature rise coefficient and the load rate is determined;

[0021] According to the first relationship, the second relationship and the preset temperature rise function, the transient temperature rise model of the specific point is determined.

[0022] Further, the first relationship is:

[0023] a=111.555x 1.58 ;

[0024] The second relationship is:

[0025]

[0026] Wherein, x is the load rate.

[0027] Further, the specific point is a hot spot in the dry-type transformer.

[0028] Further, the hot spot is a point in the middle and upper region of the low-voltage winding region in the dry-type transformer.

[0029] According to another aspect of the present application, a temperature rise determination device of a dry-type transformer is provided, which comprises:

[0030] a model establishing module, configured to establish a geometric model of the dry-type transformer, wherein the geometric model is determined by heat sources in the dry-type transformer;

[0031] a transient analysis module, configured to perform transient analysis on natural convection in the dry-type transformer according to the geometric model, and determine temperature variation of a specific point in the dry-type transformer under different load rates;

[0032] a model determination module, configured to determine a transient temperature rise model of the specific point according to the variation, wherein the temperature rise model is a corresponding relationship model of temperature rise value, load rate and working time of the specific point;

[0033] a temperature rise determination module, configured to determine the temperature rise value of the specific point in the working process of the dry-type transformer according to the transient temperature rise model.

[0034] Further, the model establishing module comprises:

[0035] a three-dimensional model constructing unit, configured to construct a three-dimensional model of the dry-type transformer according to the actual structure of the dry-type transformer;

[0036] a two-dimensional model determining unit, configured to determine heat source position information of the dry-type transformer according to electromagnetic field simulation information of the three-dimensional model, and perform cross-section division on devices releasing the heat sources to determine two-dimensional models of the devices, the two-dimensional models being the geometric model.

[0037] The temperature rise determination method of the dry-type transformer provided by the embodiment of the present application can quickly obtain the temperature rise distribution of the dry-type transformer under different load rates.

[0038] It is to be understood that the details described in this section are not intended to identify key or critical elements of the embodiments of the application or to limit the scope of the application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative effort based on these drawings.

[0040] Figure 1 is a flow chart of a temperature rise determination method of a dry-type transformer according to an embodiment of the present application;

[0041] Figure 2 is a front view of a three-dimensional model of a dry-type transformer according to an embodiment of the present application;

[0042] Figure 3 is a side view of a three-dimensional model of a dry-type transformer according to an embodiment of the present application;

[0043] Figure 4 is a structural schematic diagram of a dry-type transformer according to an embodiment of the present application;

[0044] Figure 5 is a relationship curve between temperature rise value and working time when the load rate is 0.4 according to an embodiment of the present application;

[0045] Figure 6 is a relationship curve between temperature rise value and working time when the load rate is 0.5 according to an embodiment of the present application;

[0046] Figure 7 is a relationship curve between temperature rise value and working time when the load rate is 0.6 according to an embodiment of the present application;

[0047] Figure 8 is a relationship curve between temperature rise value and working time when the load rate is 0.7 according to an embodiment of the present application;

[0048] Figure 9 is a relationship curve between temperature rise value and working time when the load rate is 0.8 according to an embodiment of the present application;

[0049] Figure 10 is a relationship curve between temperature rise value and working time when the load rate is 0.9 according to an embodiment of the present application;

[0050] Figure 11is a relationship curve between temperature rise value and working time when the load rate is 1.0 according to the embodiment of the present application;

[0051] Figure 12 is a relationship curve between load rate and temperature rise coefficient according to the embodiment of the present application;

[0052] Figure 13 is a relationship curve between load rate and time constant according to the embodiment of the present application;

[0053] Figure 14 is a structure schematic diagram of a temperature rise determination device of a dry-type transformer according to the embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to make the personnel in the technical field better understand the present application scheme, the technical scheme in the embodiment of the present application will be described clearly and completely in combination with the drawings in the embodiment of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, not all. Based on the embodiment in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0055] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0056] The embodiment of the present application provides a temperature rise determination method of a dry-type transformer, Figure 1 is a flow chart of a temperature rise determination method of a dry-type transformer according to the embodiment of the present application, referring to Figure 1 The temperature rise determination method of the dry-type transformer comprises:

[0057] S110, establishing a geometric model of the dry-type transformer; wherein the geometric model is determined by a heat source in the dry-type transformer.

[0058] The heat source is the heat source of the dry-type transformer in the working process. Specifically, Figure 2 is a front view of a three-dimensional model of the dry-type transformer according to the embodiment of the present application,Figure 3 is a side view of a three-dimensional model of a dry-type transformer provided according to an embodiment of the present application, as Figure 2 and Figure 3 shown, a three-dimensional model of a dry-type transformer is constructed according to an actual structure of the dry-type transformer, and the formed three-dimensional model is imported into simulation software, heat source position information of the dry-type transformer in a working process is determined through the simulation software, and a two-dimensional model of the dry-type transformer is established according to the heat source position information, wherein the two-dimensional model of the dry-type transformer is a geometric model of the dry-type transformer.

[0059] S120, transient analysis is performed on the natural convection in the dry-type transformer according to the geometric model to determine temperature variation of a specific point in the dry-type transformer under different load rates.

[0060] The method of transient analysis can better analyze the internal temperature variation of the dry-type transformer in a long-time working process, and simulation images can be easily obtained through the simulation software, so that the error caused by too many split grids in the steady-state analysis process can be avoided. The specific point can be determined according to the heat source position in the geometric model.

[0061] Specifically, the internal temperature distribution of the dry-type transformer can be collected in real time, and the specific collection frequency can be set according to the actual situation, which is not limited by the embodiments of the present application. According to the internal temperature distribution of the dry-type transformer, the specific point in the dry-type transformer is determined, and then the temperature variation of the specific point in the dry-type transformer under different load rates is determined. For example, the range of the load rate can be 【0.4, 1.0】.

[0062] S130, according to the variation, a transient temperature rise model of the specific point is determined, wherein the temperature rise model is a corresponding relationship model of the temperature rise value of the specific point, the load rate and the working time.

[0063] Specifically, the relationship curve between the temperature rise value of the specific point and the working time under different load rates can be determined according to the temperature rise value of the specific point, the working time and different load rates, and then the relationship function between the temperature rise value of the specific point and the working time under different load rates is fitted, and according to all the relationship functions obtained, the corresponding relationship between the coefficients in the relationship function and the load rate is determined, and then the transient temperature rise model of the specific point can be determined.

[0064] S140, according to the transient temperature rise model, the temperature rise value of the specific point in the working process of the dry-type transformer is determined.

[0065] For example, the load rate and the working time of the dry-type transformer are input into the transient temperature rise model, and then the temperature rise value of the specific point at each moment in the working process of the dry-type transformer can be determined.

[0066] The temperature rise determination method of the dry-type transformer provided by the embodiment of the present application, by establishing the geometric model of the dry-type transformer, the natural convection inside the dry-type transformer is analyzed according to the geometric model, the temperature change of the specific point inside the dry-type transformer under different load rates is determined, the simulation image is obtained by the method of transient analysis through the simulation software, then the transient temperature rise model of the specific point is determined according to the change, and the temperature rise value of the specific point in the working process of the dry-type transformer is determined according to the transient temperature rise model, so that the temperature rise distribution of the dry-type transformer under different load rates can be quickly obtained.

[0067] Figure 4 The structural schematic diagram of the dry-type transformer provided by the embodiment of the present application, optionally, referring to Figure 4 , the geometric model of the dry-type transformer is established, which comprises:

[0068] The three-dimensional model of the dry-type transformer is constructed according to the actual structure of the dry-type transformer;

[0069] According to the electromagnetic field simulation information of the three-dimensional model, the heat source position information of the dry-type transformer is determined, and the cross section of the device releasing the heat source is divided to determine the two-dimensional model of the device, and the two-dimensional model is the geometric model.

[0070] For example, the three-dimensional model 1 of the dry-type transformer is constructed by drawing through the CAD software according to the actual structure of the dry-type transformer, and the formed three-dimensional model is imported into the comsol simulation software, and the electromagnetic field simulation information of the three-dimensional model 1 obtained in the comsol simulation software can determine the heat source position information of the dry-type transformer in the working process, that is, the three cylindrical bodies in the three-dimensional model 1 are the heat sources of the dry-type transformer in the working process, according to the heat source position information, the cylindrical body in the middle position of the three-dimensional model 1 is selected as the object of cross section division, and the narrow edge cross section A-A shown in Figure 4 is the cross section to determine the two-dimensional model 2 of the dry-type transformer. In the process of establishing the geometric model of the dry-type transformer, the hanger, high-voltage connecting rod, brace and other devices of the dry-type transformer can be ignored, and only the main structure parts of the dry-type transformer such as the core, clamp and winding are left, at the same time, the edges and holes of the dry-type transformer can be deleted, so that the structure of the dry-type transformer is convenient for mesh division in the simulation software, and the mesh division can better determine the division result of the temperature field in the geometric model; in the process of establishing the geometric model of the dry-type transformer, the high-voltage winding coil and the low-voltage winding coil need to be constructed, wherein the high-voltage winding coil is a multi-layer segmented cylindrical coil wound by flat copper wire, and the low-voltage winding coil is a foil coil wound by copper foil in axial continuity.

[0071] Optionally, the transient temperature rise model of the specific point is determined according to the change, which comprises:

[0072] According to the change and the preset temperature rise function, the temperature rise formula of the specific point under multiple different load rates is determined;

[0073] According to the temperature rise formula under multiple different load rates, the transient temperature rise model of the specific point is determined.

[0074] The preset temperature rise function can be selected according to actual conditions, and the embodiment of the application does not limit this. Specifically, according to the temperature rise value of the specific point of the dry-type transformer, the working time, the different load rates and the preset temperature rise function, the relationship curve of the temperature rise value and the working time under different load rates and the temperature rise formula under different load rates can be obtained, for example, Figure 5 is the relationship curve of the temperature rise value and the working time when the load rate is 0.4 according to the embodiment of the application, Figure 6 is the relationship curve of the temperature rise value and the working time when the load rate is 0.5 according to the embodiment of the application, Figure 7 is the relationship curve of the temperature rise value and the working time when the load rate is 0.6 according to the embodiment of the application, Figure 8 is the relationship curve of the temperature rise value and the working time when the load rate is 0.7 according to the embodiment of the application, Figure 9 is the relationship curve of the temperature rise value and the working time when the load rate is 0.8 according to the embodiment of the application, Figure 10 is the relationship curve of the temperature rise value and the working time when the load rate is 0.9 according to the embodiment of the application, Figure 11 is the relationship curve of the temperature rise value and the working time when the load rate is 1.0 according to the embodiment of the application.

[0075] According to the temperature rise formula under different load rates, the corresponding relationship between the unknown coefficients in the preset temperature rise function and different load rates can be determined, and according to the corresponding relationship between the unknown coefficients in the preset temperature rise function and different load rates, the transient temperature rise model of the specific point can be determined.

[0076] Optionally, the preset temperature rise function is:

[0077]

[0078] Wherein Y is the temperature rise value, t is the working time, a is the temperature rise coefficient, and b is the time constant.

[0079] Specifically, the temperature rise coefficient a and the time constant b can be obtained by the temperature rise value of the specific point of the dry-type transformer, the working time and the different load rates, and the relationship table or relationship formula of the temperature rise coefficient a and the different load rates and the relationship table or relationship formula of the time constant b and the different load rates, for example, Table 1 lists the relationship table of different load rates and the temperature rise coefficient a and the time constant b.

[0080] Table 1 Relationship table of load rate and temperature rise coefficient a and time constant b

[0081] Load rate Temperature rise coefficient a Time constant b 0.4 25.31072 1.2176 0.5 36.9612 1.0356 0.6 50.0204 0.9287 0.7 64.1040 0.8460 0.8 79.1375 0.78375 0.9 94.7062 0.7278 1.0 110.7906 0.6823

[0082] Figure 12 a is a relationship curve of load rate and temperature rise coefficient provided according to an embodiment of the application, Figure 13 b is a relationship curve of load rate and time constant provided according to an embodiment of the application, and Figure 12 and Figure 13 the transient temperature rise model of the specific point is determined according to the temperature rise formula under multiple different load rates, and includes:

[0083] the second relationship between the time constant and the load rate is determined according to the temperature rise formula under multiple different load rates, and the first relationship between the temperature rise coefficient and the load rate is determined;

[0084] the transient temperature rise model of the specific point is determined according to the first relationship, the second relationship and the preset temperature rise function.

[0085] Specifically, as shown in Figure 12 and Figure 13 , according to the temperature rise formula under multiple different load rates, the corresponding relationship between the temperature rise coefficient a and the different load rates and the corresponding relationship between the time constant b and the different load rates can be obtained, and then the relationship graph of the temperature rise coefficient a and the different load rates and the relationship graph of the time constant b and the different load rates are obtained, the first relationship between the temperature rise coefficient and the load rate can be fitted through the relationship graph of the temperature rise coefficient a and the different load rates, the second relationship between the time constant and the load rate can be fitted through the relationship graph of the time constant b and the different load rates, and finally the transient temperature rise model of the specific point is determined according to the first relationship, the second relationship and the preset temperature rise function.

[0086] Optionally, the first relationship is:

[0087] a = 111.555x 1.58 ;

[0088] The second relationship is:

[0089]

[0090] wherein x is the load rate.

[0091] Specifically, the transient temperature rise model is:

[0092]

[0093] When the load rate x of the dry-type transformer is determined, the temperature rise value of the dry-type transformer at each moment at a specific point in the working process can be determined.

[0094] Optionally, the specific point is a hot spot in the dry-type transformer.

[0095] Specifically, the hot spot is a selection point of the hottest position at a heat source in the working process of the dry-type transformer, and since the probability of overheat problem at the hottest position is relatively large in the actual working process of the dry-type transformer, selecting the hottest position at the heat source can ensure the authenticity and effectiveness of the test.

[0096] Optionally, the hot spot is a point in the middle and upper region of the low-voltage winding region of the dry-type transformer.

[0097] Specifically, the internal temperature field of the dry-type transformer is axisymmetrically distributed under the condition of natural heat exchange, the low-voltage winding region belongs to the hottest temperature region, and the middle and upper region of the low-voltage winding region is the hottest position of the hottest temperature region, and since the probability of overheat problem at the hottest position is relatively large in the actual working process of the dry-type transformer, selecting the middle and upper region of the low-voltage winding region can ensure the authenticity and effectiveness of the test. The middle and upper region of the low-voltage winding region is the hottest position of the hottest temperature region because the air in the air duct of the dry-type transformer expands due to heat, flows upward along the air duct, and gradually reduces the flow rate due to friction with the wall surface during the flow process, and thus the heat dissipation effect is poor, and thus the temperature is the highest.

[0098] The embodiment of the present application provides a temperature rise determination device of a dry-type transformer, Figure 14 is a structural schematic diagram of the temperature rise determination device of the dry-type transformer, and the temperature rise determination device of the dry-type transformer 200 comprises: Figure 14

[0099] The model establishing module 210 is configured to establish a geometric model of the dry-type transformer, and the geometric model is determined by a heat source in the dry-type transformer.

[0100] The transient analysis module 220 is configured to perform transient analysis on the internal natural convection of the dry-type transformer according to the geometric model, and determine the temperature change of a specific point in the dry-type transformer under different load rates.

[0101] The model determination module 230 is configured to determine a transient temperature rise model of the specific point according to the change, wherein the temperature rise model is a corresponding relationship model of the temperature rise value of the specific point, the load rate and the working time.

[0102] The temperature rise determination module 240 is configured to determine the temperature rise value of the specific point in the working process of the dry-type transformer according to the transient temperature rise model.

[0103] Further, the model establishing module 210 comprises:

[0104] The three-dimensional model construction unit is configured to construct a three-dimensional model of the dry-type transformer according to the actual structure of the dry-type transformer.

[0105] ​The two-dimensional model determining unit is configured to determine heat source position information of the dry-type transformer according to electromagnetic field simulation information of the three-dimensional model, and to determine a two-dimensional model of the device releasing the heat source by cross-sectionally dividing the device, the two-dimensional model being a geometric model.

[0106] Further, the model determining module 230 comprises:

[0107] The formula determining unit is configured to determine a temperature rise formula of the specific point under a plurality of different load rates according to the change condition and the preset temperature rise function.

[0108] The model determining unit is configured to determine a transient temperature rise model of the specific point according to the temperature rise formula under the plurality of different load rates.

[0109] Further, the preset temperature rise function is:

[0110]

[0111] wherein Y is a temperature rise value, t is working time, a is a temperature rise coefficient, and b is a time constant.

[0112] Further, the model determining unit comprises:

[0113] The relationship formula determining sub-unit is configured to determine a second relationship formula between the time constant and the load rate and a first relationship formula between the temperature rise coefficient and the load rate according to the temperature rise formula under the plurality of different load rates.

[0114] The model determining sub-unit is configured to determine the transient temperature rise model of the specific point according to the first relationship formula, the second relationship formula and the preset temperature rise function.

[0115] Further, the first relationship formula is:

[0116] a = 111.555x 1.58 ;

[0117] The second relationship formula is:

[0118]

[0119] wherein x is a load rate.

[0120] Further, the specific point is a hot spot in the dry-type transformer.

[0121] Further, the hot spot is a point in a middle upper region of a low-voltage winding region of the dry-type transformer.

[0122] The temperature rise determining device of the dry-type transformer provided by the embodiments of the present application can perform the temperature rise determining method of the dry-type transformer provided by any of the embodiments of the present application, and has the corresponding function modules and beneficial effects of the performing method.

[0123] It should be understood that the various forms of flow shown above can be used to reorder, add, or remove steps. For example, the steps recited in the present application can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which are not limited herein.

[0124] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of temperature rise determination of a dry-type transformer, characterized by, The method comprises the following steps: establishing a geometric model of the dry-type transformer, wherein the geometric model is determined by heat sources in the dry-type transformer; performing transient analysis on natural convection in the dry-type transformer according to the geometric model to determine temperature variation of a specific point in the dry-type transformer under different load rates; determining a transient temperature rise model of the specific point according to the variation, wherein the temperature rise model is a corresponding relationship model of temperature rise value, load rate and working time of the specific point; determining the temperature rise value of the specific point in the working process of the dry-type transformer according to the transient temperature rise model; wherein, according to the variation, the transient temperature rise model of the specific point is determined, comprising: determining a temperature rise formula of the specific point under a plurality of different load rates according to the variation and a preset temperature rise function; determining the transient temperature rise model of the specific point according to the temperature rise formula under the plurality of different load rates; determining the transient temperature rise model of the specific point according to the temperature rise formula under the plurality of different load rates, comprising: determining a second relationship between time constant and load rate and a first relationship between temperature rise coefficient and load rate according to the temperature rise formula under the plurality of different load rates; determining the transient temperature rise model of the specific point according to the first relationship, the second relationship and a preset temperature rise function; the first relationship is: a = 111.555 x 1.58 ; the second relationship is: wherein, x is the load rate; the preset temperature rise function is: wherein, Y is the temperature rise value, t is the working time, a is the temperature rise coefficient, and b is the time constant.

2. The method of determining temperature rise of a dry-type transformer according to claim 1, wherein The method comprises the following steps: constructing a three-dimensional model of the dry-type transformer according to the actual structure of the dry-type transformer; determining heat source position information of the dry-type transformer and performing cross-section division on a device releasing the heat source according to electromagnetic field simulation information of the three-dimensional model to determine a two-dimensional model of the device, and the two-dimensional model is the geometric model.

3. The method of determining temperature rise of a dry-type transformer according to claim 1, wherein The specific point is a hot spot in the dry-type transformer.

4. The temperature rise determination method of the dry-type transformer according to claim 3, wherein, the hot spot is a point in the middle and upper region of the low-voltage winding region of the dry-type transformer.

5. A temperature rise determination device for a dry-type transformer, characterized by comprising: The method comprises the following steps: a model establishing module is configured to establish a geometric model of the dry-type transformer, wherein the geometric model is determined by heat sources in the dry-type transformer; a transient analysis module is configured to perform transient analysis on natural convection in the dry-type transformer according to the geometric model to determine temperature variation of a specific point in the dry-type transformer under different load rates; a model determining module is configured to determine a transient temperature rise model of the specific point according to the variation, wherein the temperature rise model is a corresponding relationship model of temperature rise value, load rate and working time of the specific point; a temperature rise determining module is configured to determine the temperature rise value of the specific point in the working process of the dry-type transformer according to the transient temperature rise model; wherein, the model determining module is specifically configured to: determine a temperature rise formula of the specific point under a plurality of different load rates according to the variation and a preset temperature rise function; determining a transient temperature rise model of the specific point according to the temperature rise formulas under the plurality of different load rates; determining a transient temperature rise model of the specific point according to the temperature rise formulas under the plurality of different load rates, comprising: determining a second relationship between a time constant and a load rate and a first relationship between a temperature rise coefficient and a load rate according to the temperature rise formulas under the plurality of different load rates; determining the transient temperature rise model of the specific point according to the first relationship, the second relationship and a preset temperature rise function; the first relationship is: a = 111.555 x 1.58 ; the second relationship is: wherein x is a load rate; the preset temperature rise function is: wherein Y is a temperature rise value, t is a working time, a is a temperature rise coefficient and b is a time constant.

6. The temperature rise determination apparatus of the dry-type transformer according to claim 5, characterized by, the model establishing module comprises: a three-dimensional model constructing unit configured to construct a three-dimensional model of the dry-type transformer according to an actual structure of the dry-type transformer; a two-dimensional model determining unit configured to determine heat source position information of the dry-type transformer according to electromagnetic field simulation information of the three-dimensional model, to perform cross-section division on a device releasing the heat source, and to determine a two-dimensional model of the device, the two-dimensional model being the geometric model.

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