Method and device for determining aging degree of transformer winding and electronic equipment

Abstract

The invention discloses a method and device for determining the aging degree of a transformer winding and electronic equipment. The method comprises the steps that under the target operation condition, the short-circuit current of a winding of the transformer is determined, the target operation condition is used for describing the short-circuit fault mode of the winding and the tapping mode of the transformer, and the tapping mode refers to the position of a tapping switch of the transformer; determining a first thermally stable average temperature of the winding based on the short circuit current; under the condition that the first thermal stability average temperature is greater than or equal to a preset temperature threshold value, determining a second thermal stability average temperature of the winding; determining a larger temperature in the first thermal stability average temperature and the second thermal stability average temperature as a target thermal stability average temperature of the winding; and determining a target aging degree of the winding based on the target thermal stability average temperature. According to the invention, the technical problem of inaccurate determination result of the aging degree of the transformer winding in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the field of power systems, and in particular to a method, device and electronic equipment for determining the aging degree of transformer windings. Background Art

[0002] During operation, transformers are subject not only to overvoltages but also to short-circuit currents. External short-circuit faults can occur in operating transformers for various reasons, causing short-circuit currents in the transformer windings many times greater than the rated current. Transformer winding resistance losses are proportional to the square of the current flowing through them. Therefore, during an external short-circuit fault, the resistance losses in the windings increase significantly, causing the average temperature rise of the transformer windings to rise many times higher than during normal operation. Although the short-circuit event is short-lived, it severely tests the transformer's thermal stability. Therefore, assessing the transformer's aging at the average thermal stability temperature during a short-circuit fault is crucial for monitoring the transformer's operating condition and maintaining stable power system operation.

[0003] Related technologies typically use theoretical calculations to determine the thermally stable average temperature of a transformer during a short-circuit fault. These calculations rely on simplified assumptions and ignore factors such as the nonlinear thermal characteristics of the windings, the complexity of the cooling medium flow, and variations in the winding's heat dissipation efficiency. This results in significant errors in the thermally stable average temperature calculations, which in turn leads to inaccurate transformer aging assessments. Consequently, related technologies suffer from inaccurate determinations of transformer winding aging.

[0004] To address the above-mentioned problems, no effective solutions have been proposed so far. Summary of the Invention

[0005] The embodiments of the present application provide a method, device, and electronic device for determining the degree of aging of a transformer winding, so as to at least solve the technical problem of inaccurate results in determining the degree of aging of a transformer winding existing in the related art.

[0006] According to one aspect of an embodiment of the present application, a method for determining the degree of aging of a transformer winding is provided, comprising: determining a short-circuit current of a transformer winding under target operating conditions, wherein the target operating conditions are used to describe a short-circuit failure mode of the winding and a tapping mode of the transformer, and the tapping mode refers to a position of a tap changer of the transformer; determining a first thermally stable average temperature of the winding based on the short-circuit current; determining a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; determining the larger temperature of the first thermally stable average temperature and the second thermally stable average temperature as a target thermally stable average temperature of the winding; and determining a target degree of aging of the winding based on the target thermally stable average temperature.

[0007] According to another aspect of an embodiment of the present application, a device for determining the degree of aging of a transformer winding is provided, including: a first determination module for determining the short-circuit current of the transformer winding under target operating conditions, wherein the target operating conditions are used to describe the short-circuit failure mode of the winding and the tapping mode of the transformer, and the tapping mode refers to the position of the tap changer of the transformer; a second determination module for determining a first thermally stable average temperature of the winding based on the short-circuit current; a third determination module for determining a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; a fourth determination module for determining the larger temperature between the first thermally stable average temperature and the second thermally stable average temperature as the target thermally stable average temperature of the winding; and a fifth determination module for determining a target degree of aging of the winding based on the target thermally stable average temperature.

[0008] According to another aspect of an embodiment of the present application, a non-volatile storage medium is provided, which stores a plurality of instructions, wherein the instructions are suitable for being loaded and executed by a processor in any one of the methods for determining the degree of aging of a transformer winding.

[0009] According to another aspect of an embodiment of the present application, an electronic device is provided, comprising: one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement any one of the methods for determining the degree of aging of a transformer winding.

[0010] According to another aspect of an embodiment of the present application, a computer program product is provided, which, when executed on a data processing device, is adapted to execute the program steps of the method for determining the aging degree of a transformer winding.

[0011] In an embodiment of the present application, a short-circuit current of a transformer winding is determined under target operating conditions, wherein the target operating conditions are used to describe the short-circuit failure mode of the winding and the tapping mode of the transformer, which refers to the position of the transformer's tap changer; a first thermally stable average temperature of the winding is determined based on the short-circuit current; a second thermally stable average temperature of the winding is determined when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; the larger of the first thermally stable average temperature and the second thermally stable average temperature is determined as the target thermally stable average temperature of the winding; and a target aging degree of the winding is determined based on the target thermally stable average temperature. This achieves the purpose of calculating the first thermally stable average temperature of the winding based on the short-circuit current of the transformer winding under the target operating conditions, calculating the second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to the preset temperature threshold, and ultimately determining the aging degree of the winding based on the first thermally stable average temperature and the second thermally stable average temperature, thereby achieving the technical effect of improving the accuracy of the transformer winding aging degree determination result and thereby resolving the technical problem of inaccurate transformer winding aging degree determination results existing in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0013] Figure 1 This is a flow chart of a method for determining the aging degree of a transformer winding provided in accordance with an embodiment of the present application;

[0014] Figure 2 is a schematic diagram of an optional transformer simulation model provided according to an embodiment of the present application;

[0015] Figure 3 is a schematic diagram of an optional temperature distribution of a winding provided according to an embodiment of the present application;

[0016] Figure 4 This is a schematic diagram of an optional device for determining the aging degree of a transformer winding provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0018] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0019] According to an embodiment of the present application, a method embodiment of a method for determining the degree of aging of a transformer winding is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0020] Figure 1 is a flow chart of a method for determining the aging degree of a transformer winding according to an embodiment of the present application. Figure 1 As shown, the method includes the following steps:

[0021] Step S102: determining the short-circuit current of the transformer winding under target operating conditions, wherein the target operating conditions are used to describe the short-circuit fault mode of the winding and the tapping mode of the transformer, where the tapping mode refers to the position of the tap changer of the transformer;

[0022] It can be understood that under target operating conditions, the short-circuit current of the transformer winding is determined. The target operating conditions are used to describe the short-circuit fault mode of the transformer winding (e.g., high-voltage winding power supply, medium-voltage winding short-circuit, or high-voltage winding power supply, low-voltage winding short-circuit, etc.) and the transformer tap mode. The tap mode refers to the position of the transformer tap changer, including maximum tap, rated tap, and minimum tap. By determining the transformer operating conditions, the accuracy of the transformer winding short-circuit current determination results can be improved, thereby improving the accuracy of the winding aging assessment results.

[0023] Alternatively, when a short circuit occurs in a power system, the short-circuit current in the transformer depends primarily on the location of the short-circuit point, the strength of the system power supply, and the transformer's impedance. When the high-voltage winding is powered and the medium-voltage winding is short-circuited, the short circuit occurs on the medium-voltage winding side, meaning that most of the short-circuit current will flow directly through it. However, due to the electromagnetic coupling effect of the transformer, the short-circuit current can also indirectly affect the high-voltage and low-voltage windings. Therefore, the medium-voltage winding directly feels the impact of the short-circuit current, significantly increasing the current density and winding temperature. Regarding the high-voltage winding, although the short circuit occurs on the medium-voltage winding side, due to the mutual inductance between the transformer windings, the high-voltage winding will also sense some of the short-circuit current. Although the current magnitude is typically much smaller than that on the medium-voltage winding side, it is still sufficient to cause additional heat loss. Similar to the high-voltage winding, the low-voltage winding may also sense some of the short-circuit current. This effect is particularly significant in autotransformers, but the current is typically smaller and the impact on winding temperature is limited.

[0024] Step S104, determining a first thermally stable average temperature of the winding based on the short-circuit current;

[0025] It will be appreciated that the first thermally stable average temperature of the transformer winding is calculated based on the short-circuit current of the transformer winding under target operating conditions. By determining the first thermally stable average temperature of the winding, it is possible to determine whether the winding is in a state of excessive thermal stress, allowing necessary maintenance measures to be taken in a timely manner, such as adjusting the operating status of the transformer or performing maintenance, to prevent potential equipment damage and system failure.

[0026] In an optional embodiment, the first thermally stable average temperature of the winding is determined based on the short-circuit current, including: determining the short-circuit current density of the winding based on the short-circuit current and the cross-sectional area of ​​the winding conductor; and determining the first thermally stable average temperature based on the short-circuit current density and the initial temperature of the winding.

[0027] It can be understood that the short-circuit current density of the transformer winding under target operating conditions is determined based on the short-circuit current and the winding conductor cross-sectional area. The first thermally stable average temperature of the winding under target operating conditions is determined based on the short-circuit current and the initial winding temperature. By determining the short-circuit current density of the winding, the thermal load of the winding at the moment of short circuit can be quantified, thereby enabling a more detailed analysis of the impact of thermal stress on winding aging, especially under extreme operating conditions such as high-voltage winding power supply and medium-voltage winding short circuits or low-voltage winding short circuits.

[0028] Optionally, the first thermally stable average temperature of the transformer winding can be determined by theoretical calculation. This method determines the first thermally stable average temperature of the winding based on the short-circuit current of the winding, the cross-sectional area of ​​the wire of the winding and the initial temperature of the winding. The calculation process is simple and the calculation speed is fast. The first thermally stable average temperature of the winding can be quickly determined. Therefore, it can be used to preliminarily evaluate the temperature of the transformer winding after short circuit and determine whether there is any abnormality in the temperature of the transformer winding.

[0029] Optionally, the duration of the transformer winding's short-circuit thermal resistance current is 2 seconds. For oil-immersed copper windings, the maximum allowable average temperature of each winding (i.e., high-voltage winding, medium-voltage winding, and low-voltage winding) after a short circuit is 250°C. Furthermore, within the 2-second short-circuit duration, for autotransformers and transformers with a short-circuit current exceeding 25 times the rated current, the short-circuit duration can be less than 2 seconds. Since the winding cannot dissipate heat in such a short time, without considering the winding's heat dissipation, this heat will cause the winding temperature to rise. The winding's thermal stability capability to withstand a short circuit refers to the winding's temperature not exceeding a specified temperature within the specified short-circuit time. That is, after the transformer is short-circuited, the average temperature θ1 of each winding is less than a specified value.

[0030] Optionally, the first thermally stable average temperature θ1 of the copper winding after the transformer is suddenly short-circuited can be determined by:

[0031]

[0032] Where θ1 is the first thermally stable average temperature of the winding after t seconds of short circuit, in °C; θ0 is the initial temperature of the winding, which is the sum of the maximum ambient temperature and the average temperature rise limit of the winding, in °C; J is the short-circuit current density of the winding, in A / mm 2 (amperes per square millimeter); t is the short circuit duration in seconds.

[0033] Alternatively, for an oil-immersed copper conductor winding with Class A heat resistance, the short circuit duration t = 2s, the first thermal stability average temperature θ1 = 250°C (copper), if the initial temperature θ0 = 40 + 65 = 105°C, the maximum current density of the copper conductor winding is

[0034] Optionally, for a certain type of oil-immersed Class A transformer, the AB two-phase coils of the low-voltage winding are paper-wrapped flat copper wires with a cross-sectional area of ​​296.64 mm 2 (square millimeters), the C-phase coil is a self-adhesive transposed conductor with a conductor cross-sectional area of ​​291.27 mm 2 The medium voltage winding is a paper-wrapped flat copper conductor with a cross-sectional area of ​​182.75 mm 2The high voltage winding is a paper-wrapped flat copper wire with a cross-sectional area of ​​61.44 mm 2 Table 1 shows the short-circuit currents in each winding under different tapping modes when the high-voltage winding is powered and the medium-voltage winding is short-circuited. Table 2 shows the short-circuit currents in each winding under different tapping modes when the high-voltage winding is powered and the low-voltage winding is short-circuited.

[0035] Table 1: Short-circuit current in each winding under different tapping modes when the high-voltage winding is powered and the medium-voltage winding is short-circuited

[0036]

[0037] Table 2: When the high voltage winding is powered and the low voltage winding is short-circuited, the short-circuit current in each winding under different tapping modes

[0038]

[0039] Alternatively, take the high voltage winding as an example, when the medium voltage winding is short-circuited and the high voltage winding is powered, when the high voltage winding is at its maximum tap, the short circuit current of the high voltage winding is 1542A, and the cross-sectional area of ​​the high voltage winding wire is 61.44mm 2 , then the symmetrical short-circuit current density of the transformer high-voltage winding is the ratio of the two, 25.10A / mm 2 The above current density is much smaller than the calculated maximum current density of 96.5A / mm 2 The symmetrical short-circuit current duration is t = 2s. The maximum ambient temperature is 19.85°C, and the high-voltage winding average temperature rise limit is 65°C. The initial winding temperature of the high-voltage winding is the sum of the maximum ambient temperature and the high-voltage winding average temperature rise limit. Based on the above parameters, the first thermally stable average temperature of the high-voltage winding can be calculated using the calculation formula for the first thermally stable average temperature θ1. Table 3 shows the first thermally stable average temperatures of the high-voltage winding, medium-voltage winding, and low-voltage winding under maximum tapping and rated tapping modes.

[0040] Table 3 The first thermal stability average temperature of the high voltage winding, medium voltage winding and low voltage winding under the maximum tap and rated tap mode

[0041]

[0042] According to the calculation results of the first thermal stability average temperature of the high-voltage winding, medium-voltage winding and low-voltage winding in Table 3, it can be seen that, regardless of the maximum tapping or rated tapping mode, the calculation results of the first thermal stability average temperature of the high-voltage winding, medium-voltage winding and low-voltage winding are all lower than the maximum allowable value of 250°C for the average temperature of each winding after short circuit.

[0043] Optionally, the above-mentioned method for determining the first thermally stable average temperature of the winding can not only be used to determine the first thermally stable average temperature of the winding of a transformer with one winding, but can also be used to determine the first thermally stable average temperature of the winding of a transformer with multiple windings; at the same time, for three-phase windings (including A-phase winding, B-phase winding and C-phase winding), the above-mentioned method can not only be used to determine the first thermally stable average temperature of the three-phase winding with the same material and cross-sectional area of ​​A-phase winding, B-phase winding and C-phase winding, but can also be applied to the first thermally stable average temperature of the three-phase winding with different materials and cross-sectional areas of A-phase winding, B-phase winding and C-phase winding, and has good applicability. When the materials and cross-sectional areas of the A-phase winding, the B-phase winding and the C-phase winding are the same, the first thermally stable average temperatures corresponding to the A-phase winding, the B-phase winding and the C-phase winding respectively determined by theoretical calculation are the same, that is, the first thermally stable average temperature of the winding; when the materials and cross-sectional areas of the A-phase winding, the B-phase winding and the C-phase winding are different, the first thermally stable average temperatures corresponding to the A-phase winding, the B-phase winding and the C-phase winding respectively can be determined by theoretical calculation, and the larger temperature value can be used as the first thermally stable average temperature of the winding, which is used to evaluate the aging degree of the winding under extreme conditions and improve the safe and reliable operation of the power system.

[0044] Step S106, determining a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold;

[0045] It can be understood that the first thermally stable average temperature of the winding determined under the target operating conditions is compared with a preset temperature threshold. If the first thermally stable average temperature is less than the preset temperature threshold, the winding temperature is normal. If the first thermally stable average temperature is greater than or equal to the preset temperature threshold, the winding temperature is too high and the winding operating state may be abnormal. In this case, in order to detect the state of the winding and maintain the safe and stable operation of the power system, it is necessary to perform more accurate temperature detection on the winding and determine the second thermally stable average temperature of the winding. By setting the preset temperature threshold and calculating the second thermally stable average temperature, the safe state of the winding under short-circuit conditions can be more accurately determined, avoiding accelerated aging of the winding or insulation damage due to overheating, and ensuring the safe operation of the power system.

[0046] In an optional embodiment, determining the second thermally stable average temperature of the winding includes: constructing a simulation model of the transformer; determining initial conditions and boundary conditions of the transformer, wherein the initial conditions are parameter values ​​of parameters used to describe the thermal state of the transformer at the beginning of the simulation, and the boundary conditions are used to describe the convective heat transfer process between the cooling medium and the winding of the transformer; based on the initial conditions and the boundary conditions, using the simulation model, determining the temperature distribution of the winding; and determining the second thermally stable average temperature based on the temperature distribution and the volume of the winding.

[0047] It can be understood that in order to more accurately detect the temperature of the winding and improve the accuracy of the determination of the winding's second thermally stable average temperature, the winding's second thermally stable average temperature under target operating conditions is determined in the following manner. First, a simulation model of the transformer is constructed. Second, initial conditions for the transformer's parameters describing its thermal state at the start of the simulation are determined, as well as boundary conditions for the transformer describing the convective heat transfer process between the transformer's cooling medium and the winding. Next, these initial and boundary conditions are input into the transformer's simulation model to determine the winding's temperature distribution. Finally, based on the winding's temperature distribution determined using the simulation model and the winding's volume, the winding's second thermally stable average temperature is determined. Determining the second thermally stable average temperature using the transformer's simulation model can provide a detailed representation of the transformer's internal temperature distribution, including the locations of hot and cold spots and temperature variation trends, thereby improving the accuracy of the winding's second thermally stable average temperature determination.

[0048] Alternatively, the finite element method can be used to calculate the second thermally stable average temperature of the transformer winding. Before the calculation, the initial conditions and boundary conditions of the solution domain must be determined. During the internal temperature conduction process of the transformer, the heat exchange between the transformer oil and the windings is convective heat transfer, which satisfies the third type of boundary conditions. The boundary conditions of the transformer can be determined as follows:

[0049]

[0050] Where λ represents the thermal conductivity of transformer oil, h represents the convection heat transfer coefficient, T f and T w are the temperature of transformer oil and the temperature of winding respectively, It represents the temperature gradient of the winding along the normal direction, n represents the normal direction, and w represents the winding.

[0051] Optionally, a third type of boundary condition, also known as a convection boundary condition, refers to conditions that allow heat exchange via convection between the surface of an object and the surrounding fluid (such as air, water, or transformer oil). This third type of boundary condition describes the relationship between the surface temperature of an object and the temperature of its surroundings, and how this relationship is affected by the convection heat transfer coefficient. Convection heat transfer is the process of heat transfer caused by the flow of a fluid when it comes into contact with a solid surface. In a transformer, heat generated by the windings is transferred to the oil tank through the flow of transformer oil, and then dissipated from the oil tank surface to the surrounding environment.

[0052] Optionally, you can calculate the transformer fluid field by setting initial conditions. Set the initial velocity of the transformer oil to 0 m / s (meters per second). The circulation of the transformer oil is affected by gravity acceleration and oil properties, so these parameters need to be set. Set the overall gravity acceleration to 9.8 m / s 2 (meters per second squared), the direction is the negative direction of the Z axis.

[0053] In an optional embodiment, constructing a simulation model of a transformer includes: determining structural information of the transformer, geometric parameters of the windings, and current temperature data of the area where the transformer is located; and constructing a simulation model of the transformer based on the structural information, geometric parameters, and current temperature data.

[0054] It can be understood that to construct a transformer simulation model, it is first necessary to determine the transformer's structural information, the winding's geometric information, and the current temperature data of the area where the transformer is located. Based on this information, the transformer's structural information, the winding's geometric information, and the current temperature data of the area where the transformer is located, the transformer simulation model is constructed using simulation software. By determining these detailed information, the transformer's structural information, the winding's geometric information, and the current temperature data of the area where the transformer is located, the accuracy of the constructed transformer simulation model can be improved, thereby improving the accuracy of the result of determining the second thermally stable average temperature of the winding.

[0055] Alternatively, a three-phase three-column transformer (an oil-immersed transformer) can be used as the research object to establish a transformer simulation model. To simplify the calculation, the following assumptions are made when establishing the two-dimensional simulation model of the oil-immersed transformer: (1) Structural components such as clamps, oil tanks, and magnetic shields are not considered for the time being. The simulation model mainly includes transformer oil, core, and windings; (2) An axisymmetric model is used, and only the core and windings on one side of the axis are taken; (3) The thermal conductivity, density, and specific heat capacity of the transformer core and windings are constant and do not change with temperature; (4) The external ambient temperature is assumed to be constant at 293K (Kelvin) in a normal temperature environment. Figure 2 This is a schematic diagram of an optional transformer simulation model provided according to an embodiment of the present application. Based on the above assumptions, the following is established: Figure 2 The transformer simulation model is shown.

[0056] Optionally, when analyzing the fluid-solid-thermal coupling field of the oil-immersed transformer, the thermal properties of the transformer materials need to be reset. This includes parameters such as the material's specific heat capacity, thermal conductivity, density, viscosity, and thermal diffusivity required for temperature and fluid calculations. The transformer's internal metal material parameter settings are shown in Table 4.

[0057] Table 4 Transformer internal metal material parameter settings

[0058]

[0059] In an optional embodiment, before determining the second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to the preset temperature threshold, the method further includes: determining an initial temperature threshold of the winding based on the type of the winding; and correcting the initial temperature threshold based on current environmental data of the transformer, the usage time of the winding, and historical fault data of the winding to obtain a preset temperature threshold.

[0060] It can be understood that before determining whether the temperature of the winding is abnormal based on the first thermally stable average temperature of the winding, it is first necessary to determine the preset temperature threshold of the winding. According to the type of winding, refer to the relevant standards to determine the initial temperature threshold of the winding. Collect the current environmental data of the transformer, such as ambient temperature and ambient humidity, etc., combine the use time of the winding, and the historical fault data of the winding, and correct the above-mentioned initial temperature threshold to determine the preset temperature threshold of the winding. By correcting the initial temperature threshold, the preset temperature threshold of the winding can be set according to the specific winding type, operating environment and historical fault conditions, thereby improving the accuracy of the winding aging assessment results.

[0061] Step S108, determining the larger temperature between the first thermal stability average temperature and the second thermal stability average temperature as the target thermal stability average temperature of the winding;

[0062] It can be understood that the first thermal stability average temperature and the second thermal stability average temperature of the winding are compared, and the larger temperature is determined as the target thermal stability average temperature of the winding. The target thermal stability average temperature determined based on the larger value of the first thermal stability average temperature and the second thermal stability average temperature represents the maximum temperature value that the winding may reach under the target operating conditions of the transformer, as well as the most unfavorable thermal stability state that the winding may reach. By comparing the first thermal stability average temperature of the winding obtained by theoretical calculation and the second thermal stability average temperature of the winding obtained by simulation analysis, and selecting the larger temperature of the two as the target thermal stability average temperature, the thermal behavior of the winding under the target operating conditions can be more comprehensively reflected, preventing insulation damage and other electrical faults caused by overheating of the winding, and ensuring the safety and reliability of the transformer and even the entire power system.

[0063] Step S110 : determining a target aging degree of the winding based on a target thermal stability average temperature.

[0064] As you can see, the windings are evaluated based on their target thermal stability average temperature to determine their target aging level. This determination provides a scientific basis for transformer winding maintenance, allowing operators to determine when to perform preventive maintenance, replace winding components, or conduct a comprehensive transformer inspection and upgrade based on the aging level, thereby optimizing maintenance strategies and extending the equipment's service life.

[0065] In an optional embodiment, a target aging degree of the winding is determined based on a target thermal stability average temperature, including: determining a rated operating temperature of the winding according to the type of the winding; determining an initial aging degree of the winding based on the rated operating temperature and the target thermal stability average temperature; and correcting the initial aging degree based on current environmental data of the area where the transformer is located, historical fault data of the winding, and a life curve of the winding to determine a target aging degree, wherein the life curve is used to describe how the service life of the winding changes over time.

[0066] It can be understood that the rated operating temperature of the winding is determined according to the type of winding and with reference to relevant standards; the initial aging degree of the winding is determined according to the rated operating temperature of the winding. The current environmental data of the area where the transformer is located, such as ambient temperature and ambient humidity, is collected, and combined with the historical fault data of the winding and the life curve of the winding, the above-mentioned initial aging degree is corrected to determine the target aging degree of the winding. The above-mentioned life curve is used to describe the change of the service life of the winding over time, and is obtained by analyzing the historical operating data and historical fault data of the winding of the same type as the winding. By combining the current environmental data of the area where the transformer is located, the historical fault data of the winding and the life curve of the winding, the aging degree of the winding is evaluated, and the accuracy of the determination result of the aging degree of the winding is improved, which in turn helps to predict the potential faults and safety risks of the winding and improve the operational safety and reliability of the power system.

[0067] Optionally, when a transformer contains multiple windings, such as a high-voltage winding, a medium-voltage winding, and a low-voltage winding, the first and second thermally stable average temperatures of each winding can be determined separately, and the larger of these temperatures can be used as the target thermally stable average temperature for the corresponding winding, thereby assessing the degree of aging of each winding. Furthermore, the larger of the first thermally stable average temperatures determined for each winding can be used as the first thermally stable average temperature for the entire transformer winding. Simultaneously, the highest temperature of each winding can be calculated using a simulation method as the second thermally stable average temperature for the entire transformer winding. The larger of these first and second thermally stable average temperatures can be used as the target thermally stable average temperature for the entire winding, thereby assessing the degree of aging of the entire winding.

[0068] Optionally, Figure 3 This is a schematic diagram of an optional winding temperature distribution provided according to an embodiment of the present application. According to the initial conditions and boundary conditions of the above-mentioned transformer, Figure 2 The transformer simulation model shown in the figure determines the temperature distribution of the transformer winding when the high voltage winding is powered and the medium voltage winding is short-circuited under the maximum tap. Figure 3 The temperature distribution of the transformer winding is shown in Figure 2. Figure 3 It can be seen that the transformer winding temperature is high, the transformer oil temperature shows stratification, and the temperature gradually decreases from top to bottom. The highest average temperature of the entire winding during short circuit is 107.67°C. This temperature is used as the second thermally stable average temperature of the entire winding when the high-voltage winding is powered and the medium-voltage winding is short-circuited at the maximum tap.

[0069] Alternatively, the calculation formula for the first thermally stable average temperature θ1 can be used to calculate the first thermally stable average temperature of each winding of the three-phase three-column transformer. Table 5 shows the conductor cross-sectional area of ​​each winding of the three-phase three-column transformer.

[0070] Table 5 Cross-sectional area of ​​conductors of each winding of three-phase three-column transformer

[0071]

[0072] Under maximum tapping, when the high-voltage winding supplies power and the medium-voltage winding is short-circuited, the short-circuit current of the high-voltage winding is 1542.3A, and the short-circuit current of the medium-voltage winding is 4738.2A; under maximum tapping, when the high-voltage winding supplies power and the low-voltage winding is short-circuited, the short-circuit current of the high-voltage winding is 880.9A, and the short-circuit current of the low-voltage winding is 5727.4A.

[0073] Taking the first thermal stability average temperature of the high-voltage winding when the high-voltage winding is powered and the medium-voltage winding is short-circuited at the maximum tap as an example, this article explains how to determine the first thermal stability average temperature of each winding of a three-phase three-column transformer. At the maximum tap, when the high-voltage winding is powered and the medium-voltage winding is short-circuited, the short-circuit current of the high-voltage winding is 1542.3A, and the cross-sectional area of ​​the high-voltage winding conductor is 61.44mm 2 , then the short-circuit current density J of the transformer high-voltage winding is the ratio of the two 25.10A / mm 2 , θ0 is 105℃, t is 2s, according to the calculation formula of the first thermal stability average temperature θ1, it can be obtained that under the maximum tap, when the high voltage winding is powered and the medium voltage winding is short-circuited, the first thermal stability average temperature of the high voltage winding is

[0074] Similarly, under the maximum tap, when the high voltage winding is powered and the medium voltage winding is short-circuited, the first thermal stability average temperatures of the high voltage winding, medium voltage winding and low voltage winding are shown in Table 6.

[0075] Table 6 The first thermal stability average temperature of the high voltage winding, medium voltage winding and low voltage winding when the high voltage winding is powered and the medium voltage winding is short-circuited

[0076]

[0077] Optionally, simulation calculations show that under maximum tapping, when the high-voltage winding is powered and the medium-voltage winding is short-circuited, the second thermal stability average temperature of the entire winding is 107.67°C. Theoretical calculations show that under maximum tapping, when the high-voltage winding is powered and the medium-voltage winding is short-circuited, the maximum temperature of the three windings is 113.7°C. 113.7°C is used as the first thermal stability average temperature of the entire winding. Considering the maximum temperature that the insulating paper can withstand, the maximum temperature of 113.7°C can be used as the target thermal stability average temperature condition for evaluating the aging degree of the entire transformer winding.

[0078] Through the above steps S02 to S110, the purpose of calculating the first thermal stability average temperature of the winding according to the short-circuit current of the winding of the transformer under the target operating conditions, and calculating the second thermal stability average temperature of the winding when the first thermal stability average temperature is greater than or equal to the preset temperature threshold can be achieved. Finally, the purpose of determining the aging degree of the winding according to the first thermal stability average temperature and the second thermal stability average temperature can be achieved, thereby achieving the technical effect of improving the accuracy of the results of determining the aging degree of the transformer winding, and thus solving the technical problem of inaccurate results of determining the aging degree of the transformer winding existing in the related art.

[0079] Based on the above embodiments and optional embodiments, the present application proposes an optional implementation method of a method for determining the degree of aging of a transformer winding. The optional implementation method first proposes a theoretical calculation method for the thermally stable average temperature of the winding after a sudden short circuit of the transformer (i.e., the first thermally stable average temperature), and combines examples to calculate the short-circuit current when high-voltage power supply, medium-voltage short circuit, and high-voltage power supply, low-voltage short circuit. Then, based on the short-circuit current, the thermally stable average temperature of each winding of the high, medium and low voltage windings under the maximum tap and rated tap conditions is calculated. At the same time, a simulation calculation method for the thermally stable average temperature of the winding after a sudden short circuit of the transformer (i.e., the second thermally stable average temperature) is proposed, and the finite element method is used to calculate the temperature of the transformer winding. The simulation calculation method first determines the initial conditions and boundary conditions of the solution domain, and then obtains the temperature distribution of the oil-immersed transformer obtained by simulation, and calculates the second thermally stable average temperature of the winding after a sudden short circuit of the transformer based on the temperature distribution. The steps of this implementation method include:

[0080] Step S1, calculating a first thermally stable average temperature of a winding after a sudden short circuit of the transformer.

[0081] Typically, if the operating temperature of a transformer rises 6°C above the allowable temperature, the transformer's lifespan will double, a phenomenon often referred to as the 6-degree rule. Therefore, calculating the thermally stable average temperature of the winding after a short-circuit fault is crucial for assessing the degree of winding aging and, consequently, determining its service life.

[0082] Typically, the duration of a transformer winding's short-circuit thermal resistance current is 2 seconds. For oil-immersed copper windings, the maximum allowable average temperature of each winding (i.e., high-voltage winding, medium-voltage winding, and low-voltage winding) after a short circuit is 250°C. Furthermore, within a short-circuit duration of 2 seconds, for autotransformers and transformers with a short-circuit current exceeding 25 times the rated current, the short-circuit duration can be less than 2 seconds. Since the windings cannot dissipate heat in such a short time, without considering the winding's heat dissipation, this heat will cause the winding temperature to rise. The winding's thermal stability under short-circuit conditions refers to the ability of the winding to withstand temperatures exceeding a specified temperature within the specified short-circuit duration. Specifically, after a transformer short-circuit occurs, the average temperature θ1 of each winding is less than the specified value.

[0083] The method for determining the first thermally stable average temperature θ1 of the copper winding after the transformer is suddenly short-circuited is the same as that in the above embodiment, and will not be repeated here.

[0084] For an oil-immersed copper conductor winding with Class A heat resistance, the short-circuit duration is t = 2s, the first thermal stability average temperature θ1 = 250°C (copper), and if the initial temperature θ0 = 40 + 65 = 105°C, the maximum current density of the copper conductor winding is

[0085] For a certain type of oil-immersed A-class transformer, the AB two-phase coils of the low-voltage winding are paper-wrapped flat copper wires with a cross-sectional area of ​​296.64mm 2 (square millimeters), the C-phase coil is a self-adhesive transposed conductor with a conductor cross-sectional area of ​​291.27 mm 2 The medium voltage winding is a paper-wrapped flat copper conductor with a cross-sectional area of ​​182.75 mm 2 The high voltage winding is a paper-wrapped flat copper wire with a cross-sectional area of ​​61.44 mm 2 Table 1 shows the short-circuit currents in each winding under different tapping modes when the high-voltage winding is powered and the medium-voltage winding is short-circuited. Table 2 shows the short-circuit currents in each winding under different tapping modes when the high-voltage winding is powered and the low-voltage winding is short-circuited.

[0086] Taking the high voltage winding as an example, when the medium voltage winding is short-circuited and the high voltage winding is powered, the short-circuit current of the high voltage winding is 1542A when the high voltage winding is at its maximum tap. The cross-sectional area of ​​the high voltage winding wire is 61.44mm. 2 , then the symmetrical short-circuit current density of the transformer high-voltage winding is the ratio of the two, 25.10A / mm 2The above current density is much smaller than the calculated maximum current density of 96.5A / mm 2 The symmetrical short-circuit current duration is t = 2s. The maximum ambient temperature is 19.85°C, and the high-voltage winding average temperature rise limit is 65°C. The initial winding temperature of the high-voltage winding is the sum of the maximum ambient temperature and the high-voltage winding average temperature rise limit. Based on the above parameters and the calculation formula for the first thermally stable average temperature θ1, the first thermally stable average temperature of the high-voltage winding can be calculated. Table 3 shows the first thermally stable average temperatures of the high-voltage winding, medium-voltage winding, and low-voltage winding under maximum tapping and rated tapping modes.

[0087] According to the calculation results of the first thermal stability average temperature of the high-voltage winding, medium-voltage winding and low-voltage winding in Table 3, it can be seen that, regardless of the maximum tapping or rated tapping mode, the calculation results of the first thermal stability average temperature of the high-voltage winding, medium-voltage winding and low-voltage winding are all lower than the maximum allowable value of 250°C for the average temperature of each winding after short circuit.

[0088] Step S2: simulating and calculating the second thermally stable average temperature of the winding after the transformer is suddenly short-circuited.

[0089] A three-phase three-column transformer (an oil-immersed transformer) is used as the research object to establish a transformer simulation model. To simplify the calculation, the following assumptions are made when establishing the two-dimensional simulation model of the oil-immersed transformer:

[0090] (1) Without considering the structural parts such as clamps, oil tanks, and magnetic shields, the simulation model mainly includes transformer oil, core, and windings.

[0091] (2) Using an axisymmetric model, only the core and winding on one side of the axis are taken.

[0092] (3) The thermal conductivity, density and specific heat capacity of the transformer core and winding are constants and do not change with temperature.

[0093] (4) In normal temperature environment, it is assumed that the external ambient temperature is constant at 293K (Kelvin).

[0094] Based on the above assumptions, we establish Figure 2 The transformer simulation model is shown.

[0095] When analyzing the fluid-solid-thermal coupling field of the oil-immersed transformer, the thermal properties of the transformer materials must be redefined. This includes parameters such as the material's specific heat capacity, thermal conductivity, density, viscosity, and thermal diffusivity, which are required for temperature and fluid calculations. Table 4 lists the parameters for the transformer's internal metal materials.

[0096] The finite element method is used to calculate the second thermal stability average temperature of the transformer winding. Before the calculation, the initial conditions and boundary conditions of the solution domain are determined first.

[0097] During the temperature conduction process inside the transformer, the heat exchange between the transformer oil and the windings is convective heat transfer, which satisfies the third type of boundary conditions. The method for determining the boundary conditions of the transformer is the same as that in the above embodiment and will not be repeated here.

[0098] The transformer fluid field calculation also requires setting initial conditions. Set the initial velocity of the transformer oil to 0 m / s (meters per second). The circulation of the transformer oil is affected by gravity acceleration and oil properties, so these parameters need to be set. Set the overall gravity acceleration to 9.8 m / s 2 (meters per second squared), the direction is the negative direction of the Z axis.

[0099] According to the initial conditions and boundary conditions of the transformer, using Figure 2 The transformer simulation model shown in the figure determines the temperature distribution of the transformer winding when the high voltage winding is powered and the medium voltage winding is short-circuited under the maximum tap. Figure 3 The temperature distribution of the transformer winding is shown in Figure 2. Figure 3 It can be seen that the transformer winding temperature is high, the transformer oil temperature shows stratification, and the temperature gradually decreases from top to bottom. The highest average temperature of the entire winding during short circuit is 107.67°C. This temperature is used as the second thermally stable average temperature of the entire winding when the high-voltage winding is powered and the medium-voltage winding is short-circuited at the maximum tap.

[0100] The first thermally stable average temperature of each winding of the three-phase three-column transformer is calculated using the method for calculating the first thermally stable average temperature of the winding after a sudden short circuit in step S1. Table 5 shows the conductor cross-sectional area of ​​each winding of the three-phase three-column transformer.

[0101] Under maximum tapping, when the high-voltage winding supplies power and the medium-voltage winding is short-circuited, the short-circuit current of the high-voltage winding is 1542.3A, and the short-circuit current of the medium-voltage winding is 4738.2A; under maximum tapping, when the high-voltage winding supplies power and the low-voltage winding is short-circuited, the short-circuit current of the high-voltage winding is 880.9A, and the short-circuit current of the low-voltage winding is 5727.4A.

[0102] Taking the first thermal stability average temperature of the high-voltage winding when the high-voltage winding is powered and the medium-voltage winding is short-circuited at the maximum tap as an example, this article explains how to determine the first thermal stability average temperature of each winding of a three-phase three-column transformer. At the maximum tap, when the high-voltage winding is powered and the medium-voltage winding is short-circuited, the short-circuit current of the high-voltage winding is 1542.3A, and the cross-sectional area of ​​the high-voltage winding conductor is 61.44mm 2 , then the short-circuit current density J of the transformer high-voltage winding is the ratio of the two 25.10A / mm 2, θ0 is 105℃, t is 2s, according to the calculation formula of the first thermal stability average temperature θ1, it can be obtained that under the maximum tap, when the high voltage winding is powered and the medium voltage winding is short-circuited, the first thermal stability average temperature of the high voltage winding is

[0103] Similarly, under the maximum tap, when the high voltage winding is powered and the medium voltage winding is short-circuited, the first thermal stability average temperatures of the high voltage winding, medium voltage winding and low voltage winding are shown in Table 6.

[0104] Simulation calculations show that under maximum tapping conditions, with the high-voltage winding powered and the medium-voltage winding short-circuited, the second thermal stability average temperature of the entire winding is 107.67°C. Theoretical calculations show that under maximum tapping conditions, with the high-voltage winding powered and the medium-voltage winding short-circuited, the maximum temperature of the three windings is 113.7°C. This 113.7°C is used as the first thermal stability average temperature of the entire winding. Considering the maximum temperature that the insulation paper can withstand, the maximum temperature of 113.7°C is used as the target thermal stability average temperature for assessing the aging degree of the entire transformer winding.

[0105] The above optional implementation methods achieve at least the following effects: by determining the short-circuit current density of the winding, the thermal load of the winding at the moment of short circuit can be quantified, and then the influence of thermal stress on winding aging can be analyzed more finely, especially under extreme operating conditions such as high-voltage power supply, medium-voltage short circuit or low-voltage short circuit; using the simulation model of the transformer to determine the second thermal stability average temperature, the temperature distribution inside the transformer winding can be displayed in detail, including the location of hot spots and cold spots and the temperature change trend, thereby improving the accuracy of the determination result of the second thermal stability average temperature of the winding; the determination of the target aging degree provides a scientific basis for the maintenance of the transformer winding, so that the operation and maintenance personnel can determine when to perform preventive maintenance, replacement of winding components or overall inspection and upgrade of the transformer according to the aging degree, thereby optimizing the maintenance strategy and extending the service life of the equipment.

[0106] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0107] This embodiment also provides a device for determining the degree of aging of a transformer winding. This device is used to implement the above-mentioned embodiments and preferred embodiments, and details already described will not be repeated. As used below, the terms "module" and "device" may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0108] According to an embodiment of the present application, there is also provided an embodiment of a device for implementing a method for determining the aging degree of a transformer winding. Figure 4 is a schematic diagram of a device for determining the aging degree of a transformer winding according to an embodiment of the present application. Figure 4 As shown, the above-mentioned device for determining the aging degree of transformer windings includes a first determining module 402, a second determining module 404, a third determining module 406, a fourth determining module 408, and a fifth determining module 410. The device is described below.

[0109] A first determining module 402 is configured to determine a short-circuit current of a transformer winding under a target operating condition, wherein the target operating condition is used to describe a short-circuit fault mode of the winding and a tapping mode of the transformer, where the tapping mode refers to a position of a tap changer of the transformer;

[0110] A second determining module 404, connected to the first determining module 402, configured to determine a first thermally stable average temperature of the winding based on the short-circuit current;

[0111] A third determining module 406, connected to the second determining module 404, is configured to determine a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold;

[0112] A fourth determining module 408, connected to the third determining module 406, is configured to determine the larger temperature between the first thermally stable average temperature and the second thermally stable average temperature as the target thermally stable average temperature of the winding;

[0113] The fifth determining module 410 is connected to the fourth determining module 408 and is configured to determine a target aging degree of the winding based on the target thermal stability average temperature.

[0114] In an aging degree determination device for a transformer winding provided in an embodiment of the present application, a first determination module 402 is provided for determining the short-circuit current of the transformer winding under target operating conditions, wherein the target operating conditions are used to describe the short-circuit failure mode of the winding and the tapping mode of the transformer, and the tapping mode refers to the position of the tap changer of the transformer; a second determination module 404 is connected to the first determination module 402 and is used to determine a first thermally stable average temperature of the winding based on the short-circuit current; a third determination module 406 is connected to the second determination module 404 and is used to determine a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; a fourth determination module 408 is connected to the third determination module 406 and is used to determine the larger temperature of the first thermally stable average temperature and the second thermally stable average temperature as the target thermally stable average temperature of the winding; and a fifth determination module 410 is connected to the fourth determination module 408 and is used to determine a target aging degree of the winding based on the target thermally stable average temperature. The purpose of calculating the first thermal stability average temperature of the winding according to the short-circuit current of the transformer winding under the target operating conditions, and calculating the second thermal stability average temperature of the winding when the first thermal stability average temperature is greater than or equal to the preset temperature threshold, and finally determining the aging degree of the winding according to the first thermal stability average temperature and the second thermal stability average temperature, is achieved, thereby achieving the technical effect of improving the accuracy of the determination result of the aging degree of the transformer winding, and thus solving the technical problem of inaccurate determination result of the aging degree of the transformer winding existing in the related art.

[0115] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0116] It should be noted that the first determination module 402, the second determination module 404, the third determination module 406, the fourth determination module 408, and the fifth determination module 410 described above correspond to steps S102 to S110 in the embodiment. The examples and application scenarios implemented by these modules and the corresponding steps are the same, but are not limited to the contents disclosed in the above embodiment. It should be noted that the above modules, as part of the device, can be run on a computer terminal.

[0117] It should be noted that the optional or preferred implementation of this embodiment can be found in the relevant description in the embodiment, which will not be repeated here.

[0118] The above-mentioned device for determining the aging degree of the transformer winding may further include a processor and a memory, wherein the first determination module 402, the second determination module 404, the third determination module 406, the fourth determination module 408, the fifth determination module 410, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions.

[0119] The processor includes a kernel, which retrieves the corresponding program unit from memory. There can be one or more kernels. Memory may include non-permanent memory in a computer-readable medium, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory includes at least one memory chip.

[0120] An embodiment of the present application provides a non-volatile storage medium having a program stored thereon, which, when executed by a processor, implements a method for determining the degree of aging of a transformer winding.

[0121] An embodiment of the present application provides an electronic device comprising a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are performed: determining the short-circuit current of a transformer winding under target operating conditions, wherein the target operating conditions describe the short-circuit failure mode of the winding and the tapping mode of the transformer, wherein the tapping mode refers to the position of the transformer's tap changer; determining a first thermally stable average temperature of the winding based on the short-circuit current; determining a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; determining the greater of the first thermally stable average temperature and the second thermally stable average temperature as a target thermally stable average temperature of the winding; and determining a target aging degree of the winding based on the target thermally stable average temperature. The device herein may be a server, a PC, or the like.

[0122] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program initialized with the following method steps: determining the short-circuit current of a transformer winding under target operating conditions, wherein the target operating conditions are used to describe the short-circuit failure mode of the winding and the tapping mode of the transformer, and the tapping mode refers to the position of the tap changer of the transformer; determining a first thermally stable average temperature of the winding based on the short-circuit current; determining a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; determining the larger temperature of the first thermally stable average temperature and the second thermally stable average temperature as the target thermally stable average temperature of the winding; and determining a target aging degree of the winding based on the target thermally stable average temperature.

[0123] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0124] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0125] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0126] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0127] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0128] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0129] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0130] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0131] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0132] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for determining the aging degree of a transformer winding, characterized in that: include: determining a short-circuit current of a transformer winding under target operating conditions, wherein the target operating conditions are used to describe a short-circuit failure mode of the winding and a tapping mode of the transformer, wherein the tapping mode refers to a position of a tap changer of the transformer; determining a first thermally stable average temperature of the winding based on the short-circuit current; determining a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; determining the larger temperature between the first thermally stable average temperature and the second thermally stable average temperature as the target thermally stable average temperature of the winding; A target aging degree of the winding is determined based on the target thermally stable average temperature.

2. The method according to claim 1, characterized in that The step of determining a first thermally stable average temperature of the winding based on the short-circuit current comprises: determining a short-circuit current density of the winding based on the short-circuit current and a cross-sectional area of ​​a conductor of the winding; The first thermally stable average temperature is determined based on the short-circuit current density and the initial temperature of the winding.

3. The method according to claim 1, characterized in that Determining a second thermally stable average temperature of the winding includes: Constructing a simulation model of the transformer; Determining initial conditions and boundary conditions of the transformer, wherein the initial conditions are parameter values ​​of parameters used to describe the thermal state of the transformer at the beginning of the simulation, and the boundary conditions are used to describe the convective heat transfer process between the cooling medium of the transformer and the winding; Based on the initial conditions and the boundary conditions, the simulation model is used to determine the temperature distribution of the winding; The second thermally stable average temperature is determined based on the temperature distribution and the volume of the winding.

4. The method according to claim 3, characterized in that The construction of the simulation model of the transformer includes: Determining structural information of the transformer, geometric parameters of the winding, and current temperature data of the area where the transformer is located; A simulation model of the transformer is constructed based on the structural information, the geometric parameters, and the current temperature data.

5. The method according to claim 1, wherein When the first thermally stable average temperature is greater than or equal to a preset temperature threshold, before determining the second thermally stable average temperature of the winding, the method further includes: determining an initial temperature threshold of the winding based on the type of the winding; Based on the current environmental data of the transformer, the service life of the winding, and the historical fault data of the winding, the initial temperature threshold is corrected to obtain the preset temperature threshold.

6. The method according to any one of claims 1 to 5, characterized in that The step of determining a target aging degree of the winding based on the target thermal stability average temperature includes: Determining a rated operating temperature of the winding according to the type of the winding; determining an initial aging degree of the winding based on the rated operating temperature and the target thermal stability average temperature; Based on current environmental data of the area where the transformer is located, historical fault data of the winding, and a life curve of the winding, the initial aging degree is corrected to determine the target aging degree, wherein the life curve is used to describe the change in the service life of the winding over time.

7. A device for determining the aging degree of a transformer winding, characterized in that: include: a first determining module, configured to determine a short-circuit current of a transformer winding under a target operating condition, wherein the target operating condition is used to describe a short-circuit fault mode of the winding and a tapping mode of the transformer, wherein the tapping mode refers to a position of a tap changer of the transformer; a second determining module, configured to determine a first thermally stable average temperature of the winding based on the short-circuit current; a third determining module, configured to determine a second thermally stable average temperature of the winding when the first thermally stable average temperature is greater than or equal to a preset temperature threshold; a fourth determining module, configured to determine a larger temperature between the first thermally stable average temperature and the second thermally stable average temperature as a target thermally stable average temperature of the winding; A fifth determination module is configured to determine a target aging degree of the winding based on the target thermal stability average temperature.

8. A non-volatile storage medium, characterized in that: The non-volatile storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executed by the method for determining the aging degree of a transformer winding according to any one of claims 1 to 6.

9. An electronic device, characterized in that: include: One or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method for determining the degree of aging of a transformer winding as described in any one of claims 1 to 6.

10. A computer program product comprising computer instructions, characterized in that When the computer instructions are executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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