Transformer radiator and fan number determination method and device and storage medium

Abstract

The invention discloses a method and device for determining the number of radiators and fans of a transformer and a storage medium. The method comprises the steps that S11, cooling parameters of the transformer are set; s12, on the basis of the natural convection balance equation and the forced convection balance equation, the oil temperature of an inlet of a self-cooling cooling fin, the oil flow in the self-cooling cooling fin, the oil temperature of an outlet of the self-cooling cooling fin, the oil temperature of an inlet of an air-cooling cooling fin, the oil flow in the air-cooling cooling fin and the oil temperature of the outlet of the air-cooling cooling fin are obtained through calculation; s13, on the basis of the flow parameters and the temperature parameters, the top oil temperature rise and the average oil temperature rise of the transformer are obtained through calculation; and S14, comparing the top oil temperature rise and the average oil temperature rise with preset standard values respectively, if the top oil temperature rise and the average oil temperature rise are smaller than the standard values, prompting that the number of the radiators and the number of the fans are correctly set, and otherwise, returning to the step S11 to reset the number of the radiators and the number of the fans. According to the invention, the number of radiators and the number of fans can be automatically and rapidly calculated.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and in particular to a method, apparatus, and storage medium for determining the number of transformer radiators and fans. Background Technology

[0002] As is well known, power transformers contain various heat sources that generate losses, such as resistive losses and eddy current losses. Under given load and environmental conditions, the cooling system must be able to dissipate the generated heat to ensure that the transformer does not exceed the specified permissible temperature limits. If these limits are exceeded, the insulation materials may be damaged, thereby shortening the transformer's service life.

[0003] As the most widely used heat dissipation equipment for power transformers, plate radiators usually use fans to increase the airflow in order to enhance the heat dissipation effect, so that the gaps between the radiator plates can dissipate heat better. This cooling method (AF) provides a much greater heat dissipation capacity than natural convection (AN).

[0004] Currently, the thermal design of transformer products mainly relies on manual calculation of the required number of radiators and fans. Therefore, it is necessary to conduct a systematic study on the heat dissipation efficiency of transformer finned radiators under air-cooled conditions in order to achieve automatic calculation of the number of transformer radiators and fans. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one object of this invention is to provide a method, apparatus, and storage medium for determining the number of transformer radiators and fans, capable of automatically and quickly calculating the number of transformer radiators and fans.

[0006] The technical solution adopted in this invention is: In a first aspect, the present invention provides a method for determining the number of transformer radiators and fans, comprising: S11: setting transformer cooling parameters, the transformer cooling parameters including: radiator parameters, number of radiators, fan parameters, number of fans, and oil tank parameters; S12: calculating the inlet oil temperature T of the self-cooling radiator based on the natural convection balance equation and the forced convection balance equation. oil2N Oil flow rate Q in self-cooling heat sink oilN Self-cooling radiator outlet oil temperature T oil1N Air-cooled heatsink inlet oil temperature T oil2F Oil flow rate Q in air-cooled heat sink oilF 1. Air-cooled heat sink outlet oil temperature T oil1FS13: Based on the above flow and temperature parameters, calculate the top oil temperature rise and average oil temperature rise of the transformer; S14: Compare the top oil temperature rise and average oil temperature rise with the preset standard values ​​respectively. If they are less than the standard values, indicate that the number of radiators and the number of fans are set correctly. Otherwise, return to step S11 to reset the number of radiators and the number of fans.

[0007] Step 12 includes: assuming multiple unknown parameters, including: oil flow rate Q within the self-cooling heat sink. oilN Self-cooling heat sink inlet oil temperature T oil2N Self-cooling radiator outlet oil temperature T oil1N Self-cooling heat sink outlet air temperature T air2N and the average airflow velocity U of the self-cooling heat sink airN Oil flow rate Q in air-cooled heat sink oilF Air-cooled heatsink inlet oil temperature T oil2F 1. Air-cooled heat sink outlet oil temperature T oil1F and the air temperature T at the outlet of the air-cooled heat sink air2F List several equations for the unknown parameters, including: natural convection oil-side momentum balance equation, natural convection oil-side heat balance equation, natural convection air-side momentum balance equation, natural convection air-side heat balance equation, natural convection oil-side and air-side heat transfer balance equation, forced convection oil-side momentum balance equation, forced convection oil-side heat balance equation, forced convection air-side heat balance equation, forced convection oil-side and air-side heat transfer balance equation; based on these equations and constraints, solve for the values ​​of the unknown parameters; among them, the constraints include: (1) the inlet oil temperature T of the self-cooling radiator. oil2N With air-cooled heatsink inlet oil temperature T oil2F Equal, that is (2) Total transformer oil flow rate Q oil Equal to the oil flow rate Q inside the self-cooling heat sink oilN Oil flow rate Q in air-cooled heat sink oilF The sum of (3) Transformer outlet oil temperature T oil1 The mass of the oil flow within the heat sink is determined by a weighted average of the mass of the oil flow in natural convection and forced convection heat sinks. .

[0008] The equations for these multiple equations are as follows: (1) The momentum balance equation for the natural convection oil side is: ; in, In the formula, A represents the sum of the total cross-sectional areas of the oil passages. is the coefficient of thermal volume expansion of oil. Let be the density of the oil, and g be the acceleration due to gravity. To ensure an effective height difference between the heat dissipation center and the heat generation center, L is the cross-sectional area of ​​the oil passage in a single radiator fin. p The center distance of the radiator. The dynamic viscosity of the oil. It is an empirical constant. The perimeter of the oil passage cross-section of a single radiator fin; (2) The natural convection oil-side heat balance equation is: ; in, In the formula, P is the specific heat capacity of oil. N This refers to heat dissipation through natural convection. (3) The momentum balance equation for the natural convection air side is: ; in, In the formula, The average air velocity, For wall shear stress, The distance between the heatsink fins. is the coefficient of thermal expansion of air. For the density of air, The ambient temperature, , The Reynolds number of air. , The kinematic viscosity of air; (4) The heat balance equation for the air side of natural convection is: ; in, In the formula, The specific heat capacity of air. The airflow rate of natural convection. , For the width of the heatsink fins, The number of heat sink fins for self-cooling operation; (5) The heat exchange balance equation for the natural convection oil side and air side is: ; in, In the formula, , where h N The total heat transfer coefficient between the oil inside the heat sink and the air in self-cooling operation mode; (6) The momentum balance equation for the forced convection oil side is: ; in, ; (7) The forced convection oil-side heat balance equation is: ; in, ; (8) The forced convection air-side heat balance equation is: ; in, In the formula, To force the flow rate of convective air, , This refers to the outlet wind speed of the fan. The number of heat sink fins for air-cooled operation; (9) The heat exchange balance equation for the forced convection oil side and air side is: ; in, ; , where h F The total heat transfer coefficient between the oil inside the heat sink and the air in air-cooled operation.

[0009] Step 13 includes: adjusting the oil temperature T at the inlet of the self-cooling heat sink. oil2N Subtract the ambient temperature to obtain the top oil temperature rise; calculate the transformer outlet oil temperature T. oil1 Subtract the ambient temperature to calculate the bottom oil temperature rise; average the top oil temperature rise and the bottom oil temperature rise to obtain the average oil temperature rise.

[0010] The parameters of the radiator include: radiator model, radiator fin height, radiator fin width, radiator outer surface material type, radiator center distance, and radiator installation position; the parameters of the fan include: fan model, impeller diameter, and fan air volume; the parameters of the oil tank include: oil tank length, oil tank width, oil tank height, and oil tank outer surface material type.

[0011] The transformer type includes: liquid-immersed AC transformer or reactor; the transformer cooling oil type includes: mineral oil, natural ester oil or synthetic ester oil; the fan is located at the bottom of the radiator, and the radiator adopts a bottom-blowing method for airflow.

[0012] Secondly, the present invention provides a device for determining the number of transformer radiators and fans, comprising: a transformer cooling parameter setting module for setting transformer cooling parameters, including: radiator parameters, number of radiators, fan parameters, number of fans, and oil tank parameters; and an intermediate parameter calculation module for calculating the inlet oil temperature T of the self-cooling radiator based on the natural convection balance equation and the forced convection balance equation. oil2N Oil flow rate Q in self-cooling heat sink oilN Self-cooling radiator outlet oil temperature T oil1N Air-cooled heatsink inlet oil temperature T oil2F Oil flow rate Q in air-cooled heat sinkoilF 1. Air-cooled heat sink outlet oil temperature T oil1F The oil temperature rise calculation module is used to calculate the top oil temperature rise and average oil temperature rise of the transformer based on the above flow and temperature parameters. The radiator quantity and fan quantity determination module is used to compare the top oil temperature rise and the average oil temperature rise with the preset standard values ​​respectively. If they are less than the standard values, it will indicate that the radiator quantity and fan quantity are set correctly. Otherwise, if not, it will return to the transformer cooling parameter setting module to reset the radiator quantity and fan quantity.

[0013] The intermediate parameter calculation module includes an unknown parameter assumption unit, used to assume multiple unknown parameters, namely: oil flow rate Q in the self-cooling heat sink. oilN Self-cooling heat sink inlet oil temperature T oil2N Self-cooling radiator outlet oil temperature T oil1N Self-cooling heat sink outlet air temperature T air2N and the average airflow velocity U of the self-cooling heat sink airN Oil flow rate Q in air-cooled heat sink oilF Air-cooled heatsink inlet oil temperature T oil2F 1. Air-cooled heat sink outlet oil temperature T oil1F and the air temperature T at the outlet of the air-cooled heat sink air2F The equation listing unit is used to list multiple equations for the multiple unknown parameters. These multiple equations include: natural convection oil-side momentum balance equation, natural convection oil-side heat balance equation, natural convection air-side momentum balance equation, natural convection air-side heat balance equation, natural convection oil-side and air-side heat transfer balance equation, forced convection oil-side momentum balance equation, forced convection oil-side heat balance equation, forced convection air-side heat balance equation, and forced convection oil-side and air-side heat transfer balance equation. The equation solving unit is used to solve for the values ​​of the multiple unknown parameters based on the multiple equations and multiple constraints.

[0014] Thirdly, the present invention provides a device for determining the number of transformer radiators and fans, comprising a memory and a processor. The memory is used to store computer program code and transmit the computer program code to the processor. The processor is used to execute the determination method described above according to the instructions in the computer program code.

[0015] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the determination method described above.

[0016] The beneficial effects of this invention are: This invention obtains transformer cooling parameters and then calculates the top oil temperature rise and average oil temperature rise using natural convection balance equations and forced convection balance equations. The top oil temperature rise and average oil temperature rise are then compared with preset values. If they are less than the preset values, the number of radiators and fans is determined to be correct. This invention uses the calculation of the top oil temperature rise and average oil temperature rise to infer the rationality of the number of fans and radiators. Furthermore, by combining thermodynamics, computational fluid dynamics, experimental data, and the thermal properties of fluids, this invention simplifies complex problems into describable mathematical models, simplifying the tedious modeling and preprocessing processes into parameterized input. The solution process is automatically completed by the program, thus achieving automatic and rapid determination of the number of radiators and fans required for a transformer.

[0017] Furthermore, the computational model proposed in this invention obtains the desired results by solving the momentum and energy conservation equations on the oil and air sides, thus enabling a reasonable calculation of the number of radiators and fans.

[0018] In addition, when calculating the oil temperature rise, this invention no longer relies on the effective heat dissipation area provided by the radiator manufacturer, but directly uses the geometric dimensions of the radiator (such as the width, height and number of radiator fins) for calculation. This overcomes the technical problem of relying on empirical values ​​to calculate the number of radiators and the number of fans in the prior art, and achieves accurate calculation of the number of radiators and the number of fans.

[0019] Furthermore, this invention takes into account the thermal properties of fluid materials, and the cooling oil is suitable for various types such as mineral oil, natural ester oil, or synthetic ester oil, making this invention widely applicable. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating an embodiment of a method for determining the number of transformer radiators and fans according to the present invention; Figure 2 This is a schematic diagram of an embodiment of a method for determining the number of transformer radiators and fans according to the present invention; Figure 3 yes Figure 1 and Figure 2 A schematic diagram of an embodiment showing the relative positions of the transformer, radiator, and fan; Figure 4 yes Figure 1 and Figure 2 A schematic diagram of a radiator in both natural and forced convection heat transfer states; Figure 5 yes Figure 1 A flowchart illustrating an embodiment of step S12; Figure 6 This is a schematic diagram of an embodiment of a device for determining the number of transformer radiators and fans according to the present invention; Figure 7 yes Figure 6 A schematic diagram of the structure of an embodiment of the intermediate parameter calculation module 12; Figure 8 This is a schematic diagram of an embodiment of a device for determining the number of transformer radiators and fans according to the present invention. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0022] Example 1

[0023] Please refer to the following: Figures 1 to 4 , Figure 1 This is a flowchart illustrating an embodiment of a method for determining the number of transformer radiators and fans according to the present invention. Figure 1 As shown, the method includes the following steps: S11: Set the transformer cooling parameters, which include: radiator parameters, number of radiators, fan parameters, number of fans, oil tank parameters, and other parameters. The types of transformers include: liquid-immersed AC transformers or reactors. The types of cooling oil used in these transformers include: mineral oil, natural ester oil, or synthetic ester oil.

[0024] like Figure 4 As shown, the fan is located at the bottom of the radiator, and the radiator uses a bottom-blowing method for airflow.

[0025] like Figure 3 As shown, the parameters of the radiator include: radiator model, radiator fin height (in mm), radiator fin width (in mm), radiator outer surface material type, center distance between radiators (in mm), and radiator installation position.

[0026] Fan parameters include: fan model, impeller diameter (in mm), and fan air volume (in m³ / s). 3 / h).

[0027] The parameters of the fuel tank include: fuel tank length (in mm), fuel tank width (in mm), fuel tank height (in mm), and fuel tank outer surface material type.

[0028] S12: Based on the natural convection balance equation and the forced convection balance equation, the inlet oil temperature T of the self-cooling heat sink is calculated. oil2N Oil flow rate Q in self-cooling heat sink oilN Self-cooling radiator outlet oil temperature T oil1N Air-cooled heatsink inlet oil temperature T oil2F Oil flow rate Q in air-cooled heat sinkoilF 1. Air-cooled heat sink outlet oil temperature T oil1F ; Please see Figure 5 , Figure 5 This is a flowchart illustrating one embodiment of step S12. For example... Figure 5 As shown, step S12 includes: S121: Assume multiple unknown parameters; These unknown parameters include: oil flow rate Q within the self-cooling heat sink. oilN Self-cooling heat sink inlet oil temperature T oil2N Self-cooling radiator outlet oil temperature T oil1N Self-cooling heat sink outlet air temperature T air2N and the average airflow velocity U of the self-cooling heat sink airN Oil flow rate Q in air-cooled heat sink oilF Air-cooled heatsink inlet oil temperature T oil2F 1. Air-cooled heat sink outlet oil temperature T oil1F and the air temperature T at the outlet of the air-cooled heat sink air2F .

[0029] S122: List several equations for the multiple unknown parameters, including: natural convection oil-side momentum balance equation, natural convection oil-side heat balance equation, natural convection air-side momentum balance equation, natural convection air-side heat balance equation, natural convection oil-side and air-side heat transfer balance equation, forced convection oil-side momentum balance equation, forced convection oil-side heat balance equation, forced convection air-side heat balance equation, and forced convection oil-side and air-side heat transfer balance equation. The equations for these multiple equations are as follows: (1) The momentum balance equation for the natural convection oil side is: ; in, In the formula, A represents the sum of the total cross-sectional areas of the oil passages. is the coefficient of thermal volume expansion of oil. Let be the density of the oil, and g be the acceleration due to gravity. To ensure an effective height difference between the heat dissipation center and the heat generation center, L is the cross-sectional area of ​​the oil passage in a single radiator fin. p The center distance of the radiator. The dynamic viscosity of the oil. It is an empirical constant. The perimeter of the oil passage cross-section of a single radiator fin; (2) The natural convection oil-side heat balance equation is: ; in, In the formula, P is the specific heat capacity of oil.N This refers to heat dissipation through natural convection. (3) The momentum balance equation for the natural convection air side is: ; in, In the formula, The average air velocity, For wall shear stress, The distance between the heatsink fins. is the coefficient of thermal expansion of air. For the density of air, The ambient temperature, , The Reynolds number of air. , The kinematic viscosity of air; (4) The heat balance equation for the air side of natural convection is: ; in, In the formula, The specific heat capacity of air. The airflow rate of natural convection. , For the width of the heatsink fins, The number of heat sink fins for self-cooling operation; (5) The heat exchange balance equation for the natural convection oil side and air side is: ; in, In the formula, , where h N The total heat transfer coefficient between the oil inside the heat sink and the air in self-cooling operation mode; (6) The momentum balance equation for the forced convection oil side is: ; in, ; (7) The forced convection oil-side heat balance equation is: ; in, ; (8) The forced convection air-side heat balance equation is: ; in, In the formula, To force the flow rate of convective air, , This refers to the outlet wind speed of the fan. The number of heat sink fins for air-cooled operation; (9) The heat exchange balance equation for the forced convection oil side and air side is: ; in, ; , where h F The total heat transfer coefficient between the oil inside the heat sink and the air in air-cooled operation.

[0030] S123: Based on these multiple equations and constraints, the values ​​of these multiple unknown parameters are obtained by solving.

[0031] These constraints include: (1) Inlet oil temperature T of self-cooling heat sink oil2N With air-cooled heatsink inlet oil temperature T oil2F Equal, that is ; (2) Total transformer oil flow rate Q oil Equal to the oil flow rate Q inside the self-cooling heat sink oilN Oil flow rate Q in air-cooled heat sink oilF The sum of ; (3) Transformer outlet oil temperature T oil1 The mass of the oil flow within the heat sink is determined by a weighted average of the mass of the oil flow in natural convection and forced convection heat sinks. .

[0032] S13: Based on the above flow and temperature parameters, the top oil temperature rise and average oil temperature rise of the transformer are calculated. The inlet oil temperature T of the self-cooling heat sink oil2N Subtract the ambient temperature to obtain the temperature rise of the top oil layer.

[0033] The transformer outlet oil temperature T is calculated using the following formula. oil1 : .

[0034] The average temperature rise of the top layer oil and the bottom layer oil is calculated by averaging the two values.

[0035] S14: Compare the top oil temperature rise and the average oil temperature rise with the preset standard values ​​respectively. If they are less than the standard values, indicate that the number of radiators and the number of fans are set correctly. Otherwise, return to step S11 to reset the number of radiators and the number of fans.

[0036] The top layer oil temperature rise is compared with the preset first standard value, and the average oil temperature rise is compared with the preset second standard value. If the top layer oil temperature rise is less than the preset first standard value and the average oil temperature rise is less than the preset second standard value, then the system indicates that the number of radiators and the number of fans are set correctly.

[0037] Example 2 Please see Figure 6 , Figure 6This is a schematic diagram of an embodiment of a device for determining the number of transformer radiators and fans according to the present invention. Figure 6 As shown, the device includes a transformer cooling parameter setting module 11, an intermediate parameter calculation module 12, an oil temperature rise calculation module 13, and a radiator quantity and fan quantity determination module 14.

[0038] The transformer cooling parameter setting module 11 is used to set the transformer cooling parameters, which include: radiator parameters, number of radiators, fan parameters, number of fans, and oil tank parameters.

[0039] Intermediate parameter calculation module 12 is used to calculate the inlet oil temperature T of the self-cooling heat sink based on the natural convection balance equation and the forced convection balance equation. oil2N Oil flow rate Q in self-cooling heat sink oilN Self-cooling radiator outlet oil temperature T oil1N Air-cooled heatsink inlet oil temperature T oil2F Oil flow rate Q in air-cooled heat sink oilF 1. Air-cooled heat sink outlet oil temperature T oil1F .

[0040] The oil temperature rise calculation module 13 is used to calculate the top oil temperature rise and average oil temperature rise of the transformer based on the above flow parameters and temperature parameters.

[0041] The module 14 for determining the number of radiators and fans is used to compare the temperature rise of the top oil and the average temperature rise of the oil with preset standard values. If they are less than the standard values, it indicates that the number of radiators and the number of fans are set correctly. Otherwise, if they are not, it returns to the transformer cooling parameter setting module to reset the number of radiators and the number of fans.

[0042] Specifically, please refer to Figure 7 The intermediate parameter calculation module 12 includes an unknown parameter assumption unit 121, an equation listing unit 122, and an equation solving unit 123. The unknown parameter assumption unit 121 is used to assume multiple unknown parameters, including: the oil flow rate Q within the self-cooling heat sink. oilN Self-cooling heat sink inlet oil temperature T oil2N Self-cooling radiator outlet oil temperature T oil1N Self-cooling heat sink outlet air temperature T air2N and the average airflow velocity U of the self-cooling heat sink airN Oil flow rate Q in air-cooled heat sink oilF Air-cooled heatsink inlet oil temperature T oil2F 1. Air-cooled heat sink outlet oil temperature T oil1F and the air temperature T at the outlet of the air-cooled heat sink air2FEquation listing unit 122 is used to list multiple equations concerning the various unknown parameters. These equations include: natural convection oil-side momentum balance equation, natural convection oil-side heat balance equation, natural convection air-side momentum balance equation, natural convection air-side heat balance equation, natural convection oil-side and air-side heat transfer balance equation, forced convection oil-side momentum balance equation, forced convection oil-side heat balance equation, forced convection air-side heat balance equation, and forced convection oil-side and air-side heat transfer balance equation. Equation solving unit 123 is used to solve for the values ​​of the various unknown parameters based on these multiple equations and constraints.

[0043] Specifically, the working methods of each module in this embodiment have been described in detail in Embodiment 1, and will not be repeated here.

[0044] Example 3 Please see Figure 8 , Figure 8 This is a schematic diagram of an embodiment of a device for determining the number of transformer radiators and fans according to the present invention. Figure 8 As shown, the device for determining the number of transformer radiators and fans includes a memory and a processor. The memory stores computer program code and transmits the computer program code to the processor. The processor executes the determination method as described in Embodiment 1 according to the instructions in the computer program code.

[0045] Example 4 The present invention also provides a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the determination method as described in Embodiment 1.

[0046] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for determining the quantity of transformer radiators and fans, characterized in that, include: S11: Set the transformer cooling parameters, which include: radiator parameters, number of radiators, fan parameters, number of fans, and oil tank parameters; S12: Based on the natural convection balance equation and the forced convection balance equation, the inlet oil temperature T of the self-cooling heat sink is calculated. oil2N Oil flow rate Q in self-cooling heat sink oilN Self-cooling radiator outlet oil temperature T oil1N Air-cooled heatsink inlet oil temperature T oil2F Oil flow rate Q in air-cooled heat sink oilF 1. Air-cooled heat sink outlet oil temperature T oil1F ; S13: Based on the above flow and temperature parameters, the top oil temperature rise and average oil temperature rise of the transformer are calculated. S14: Compare the top oil temperature rise and the average oil temperature rise with preset standard values ​​respectively. If they are less than the standard values, indicate that the number of radiators and the number of fans are set correctly. Otherwise, return to step S11 to reset the number of radiators and the number of fans.

2. The determination method according to claim 1, characterized in that, Step 12 includes: Assume several unknown parameters, including: oil flow rate Q within the self-cooling heat sink. oilN Self-cooling heat sink inlet oil temperature T oil2N Self-cooling radiator outlet oil temperature T oil1N Self-cooling heat sink outlet air temperature T air2N and the average airflow velocity U of the self-cooling heat sink airN Oil flow rate Q in air-cooled heat sink oilF Air-cooled heatsink inlet oil temperature T oil2F 1. Air-cooled heat sink outlet oil temperature T oil1F and the air temperature T at the outlet of the air-cooled heat sink air2F ; List several equations concerning the aforementioned unknown parameters, including: natural convection oil-side momentum balance equation, natural convection oil-side heat balance equation, natural convection air-side momentum balance equation, natural convection air-side heat balance equation, natural convection oil-side and air-side heat transfer balance equation, forced convection oil-side momentum balance equation, forced convection oil-side heat balance equation, forced convection air-side heat balance equation, and forced convection oil-side and air-side heat transfer balance equation. Based on the multiple equations and multiple constraints, the values ​​of the multiple unknown parameters are obtained by solving; The plurality of constraints include: (1) Inlet oil temperature T of self-cooling heat sink oil2N With air-cooled heatsink inlet oil temperature T oil2F Equal, that is ; (2) Total transformer oil flow rate Q oil Equal to the oil flow rate Q inside the self-cooling heat sink oilN Oil flow rate Q in air-cooled heat sink oilF The sum of ; (3) Transformer outlet oil temperature T oil1 The mass of the oil flow within the heat sink is determined by a weighted average of the mass of the oil flow in natural convection and forced convection heat sinks. .

3. The determination method according to claim 2, characterized in that, The equations for the multiple equations are as follows: (1) The momentum balance equation for the natural convection oil side is: ； in, In the formula, A represents the sum of the total cross-sectional areas of the oil passages. is the coefficient of thermal volume expansion of oil. Let be the density of the oil, and g be the acceleration due to gravity. To ensure an effective height difference between the heat dissipation center and the heat generation center, L is the cross-sectional area of ​​the oil passage in a single radiator fin. p The center distance of the radiator. The dynamic viscosity of the oil. It is an empirical constant. The perimeter of the oil passage cross-section of a single radiator fin; (2) The natural convection oil-side heat balance equation is: ; in, In the formula, P is the specific heat capacity of oil. N This refers to heat dissipation through natural convection. (3) The momentum balance equation for the natural convection air side is: ; in, In the formula, The average air velocity, For wall shear stress, The distance between the heatsink fins. is the coefficient of thermal expansion of air. For the density of air, The ambient temperature, , The Reynolds number of air. , The kinematic viscosity of air; (4) The natural convection air-side heat balance equation is: ; in, In the formula, The specific heat capacity of air. The airflow rate of natural convection. , For the width of the heatsink fins, The number of heat sink fins for self-cooling operation; (5) The heat exchange balance equation for the natural convection oil side and air side is: ; in, In the formula, , where h N The total heat transfer coefficient between the oil inside the heat sink and the air in self-cooling operation mode; (6) The forced convection oil-side momentum balance equation is: ; in, ; (7) The forced convection oil-side heat balance equation is: ; in, ; (8) The forced convection air-side heat balance equation is: ; in, In the formula, To force the flow rate of convective air, , This refers to the outlet wind speed of the fan. The number of heat sink fins for air-cooled operation; (9) The heat exchange balance equation for the forced convection oil side and air side is: ; in, ; , where h F The total heat transfer coefficient between the oil inside the heat sink and the air in air-cooled operation.

4. The determination method according to claim 2, characterized in that, Step 13 includes: The inlet oil temperature T of the self-cooling heat sink oil2N Subtract the ambient temperature to obtain the temperature rise of the top oil layer; Transformer outlet oil temperature T oil1 Subtract the ambient temperature to calculate the bottom oil temperature rise; The average oil temperature rise is obtained by averaging the temperature rise of the top layer oil and the temperature rise of the bottom layer oil.

5. The determination method according to claim 1, characterized in that, The radiator parameters include: radiator model, radiator fin height, radiator fin width, radiator outer surface material type, radiator center distance, and radiator installation position. The fan parameters include: fan model, impeller diameter, and fan air volume; The parameters of the fuel tank include: fuel tank length, fuel tank width, fuel tank height, and fuel tank outer surface material type.

6. The determination method according to claim 1, characterized in that, The transformer type includes: liquid-immersed AC transformer or reactor; the transformer cooling oil type includes: mineral oil, or natural ester oil or synthetic ester oil; The fan is located at the bottom of the radiator, and the radiator uses a bottom-blowing method for airflow.

7. A device for determining the quantity of transformer radiators and fans, characterized in that, include: The transformer cooling parameter setting module is used to set the transformer cooling parameters, which include: radiator parameters, number of radiators, fan parameters, number of fans, and oil tank parameters. The intermediate parameter calculation module is used to calculate the inlet oil temperature T of the self-cooling heat sink based on the natural convection balance equation and the forced convection balance equation. oil2N Oil flow rate Q in self-cooling heat sink oilN Self-cooling radiator outlet oil temperature T oil1N Air-cooled heatsink inlet oil temperature T oil2F Oil flow rate Q in air-cooled heat sink oilF 1. Air-cooled heat sink outlet oil temperature T oil1F ; The oil temperature rise calculation module is used to calculate the top oil temperature rise and average oil temperature rise of the transformer based on the above flow and temperature parameters. The module for determining the number of radiators and fans is used to compare the top oil temperature rise and the average oil temperature rise with preset standard values. If they are less than the standard values, it indicates that the number of radiators and the number of fans are set correctly; otherwise, it returns to the transformer cooling parameter setting module to reset the number of radiators and the number of fans.

8. The determining device according to claim 7, characterized in that, The intermediate parameter calculation module includes: An unknown parameter assumption unit is used to assume multiple unknown parameters, including: the oil flow rate Q inside the self-cooling heat sink. oilN Self-cooling heat sink inlet oil temperature T oil2N Self-cooling radiator outlet oil temperature T oil1N Self-cooling heat sink outlet air temperature T air2N and the average airflow velocity U of the self-cooling heat sink airN Oil flow rate Q in air-cooled heat sink oilF Air-cooled heatsink inlet oil temperature T oil2F 1. Air-cooled heat sink outlet oil temperature T oil1F and the air temperature T at the outlet of the air-cooled heat sink air2F ; The equation listing unit is used to list multiple equations for the multiple unknown parameters, including: natural convection oil-side momentum balance equation, natural convection oil-side heat balance equation, natural convection air-side momentum balance equation, natural convection air-side heat balance equation, natural convection oil-side and air-side heat transfer balance equation, forced convection oil-side momentum balance equation, forced convection oil-side heat balance equation, forced convection air-side heat balance equation, and forced convection oil-side and air-side heat transfer balance equation. The equation solving unit is used to solve for the values ​​of the multiple unknown parameters based on the multiple equations and multiple constraints.

9. A device for determining the quantity of transformer radiators and fans, characterized in that, The device includes a memory and a processor, wherein the memory is used to store computer program code and to transfer the computer program code to the processor; the processor is used to execute the determination method as described in any one of claims 1 to 6 according to instructions in the computer program code.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the determination method as described in any one of claims 1 to 6.

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