Methods, devices, equipment and storage media for determining the current carrying capacity of transformers

Abstract

This application discloses a method, apparatus, device, and storage medium for determining the current carrying capacity of a transformer. The method includes: acquiring transformer operating data and temperature data; determining heat exchange data based on the temperature data; determining heat source data based on the operating data; determining an insulation temperature change curve based on the heat exchange data and heat source data; and determining the transformer's current carrying capacity based on the insulation temperature change curve. This application helps improve the accuracy of transformer current carrying capacity calculation.

Description

Technical Field

[0001] This application relates to the field of transformer current-carrying capacity calculation technology, and in particular to a method, apparatus, equipment and storage medium for determining the current-carrying capacity of a transformer. Background Technology

[0002] Current carrying capacity refers to the maximum current a transformer can withstand, representing the maximum current a transformer can transmit. Transformer current carrying capacity is divided into two types: standard current carrying capacity and rated current carrying capacity. Standard current carrying capacity refers to the maximum current a transformer can withstand under normal operating conditions, typically 80% of the rated current carrying capacity. Rated current carrying capacity refers to the maximum current a transformer can withstand under long-term continuous operation.

[0003] Current current-carrying capacity calculations assume the transformer operates under constant conditions to estimate its current-carrying capacity under those conditions. However, the operating data and ambient temperature of dry-type transformers during continuous operation are not constant; the transformer and its environment are constantly interacting and changing. This results in current-type current-carrying capacity calculations being merely reference values ​​and failing to reflect the actual current-carrying capacity of the dry-type transformer, leading to poor accuracy. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, embodiments of this application provide a method, apparatus, device, and storage medium for determining the current carrying capacity of a transformer. Heat exchange data is determined based on the transformer's temperature data, and heat source data is determined based on the transformer's operating data. Based on the heat exchange data and heat source data, the core insulation temperature and winding insulation temperature are extrapolated to obtain an insulation temperature change curve. The transformer's current carrying capacity is determined using this insulation temperature change curve. By considering the influence of transformer operating data and temperature data on the transformer's current carrying capacity, the accuracy of the current carrying capacity calculation is improved.

[0005] In a first aspect, embodiments of this application provide a method for determining the current carrying capacity of a transformer, applied to a transformer controller. The transformer further includes an iron core and windings. A first temperature sensor is deployed on the surface of the iron core, and a second temperature sensor is deployed on the surface of the windings. The windings are connected to an electrical data acquisition device. The electrical data acquisition device, the first temperature sensor, and the second temperature sensor are all communicatively connected to the controller. A third temperature sensor is deployed on the surface of the transformer and is communicatively connected to the controller. The method includes:

[0006] The transformer's operating data and temperature data are acquired; wherein, the operating data includes winding current and operating power, both of which are acquired by the electrical data acquisition device; the temperature data includes: core insulation temperature, winding insulation temperature and ambient temperature, wherein the core insulation temperature is acquired by the first temperature sensor, the winding insulation temperature is acquired by the second temperature sensor, and the ambient temperature is acquired by the third temperature sensor;

[0007] Based on the temperature data, heat exchange data is determined; the heat exchange data includes the core heat flow rate and the winding heat flow rate.

[0008] Based on the operational data, heat source data is determined; the heat source data includes the core heating power and the winding heating power.

[0009] Based on the heat exchange data and the heat source data, an insulation temperature change curve is determined; the insulation temperature change curve includes the core insulation temperature change curve and the winding insulation temperature change curve.

[0010] Based on the insulation temperature change curve, the current carrying capacity of the transformer is determined.

[0011] Secondly, embodiments of this application provide a current-carrying capacity determination device applied to a transformer controller. The transformer further includes an iron core and windings. A first temperature sensor is deployed on the surface of the iron core, and a second temperature sensor is deployed on the surface of the windings. The windings are connected to an electrical data acquisition unit. The electrical data acquisition unit, the first temperature sensor, and the second temperature sensor are all communicatively connected to the controller. A third temperature sensor is deployed on the surface of the transformer and is communicatively connected to the controller. The device includes:

[0012] The acquisition unit is used to acquire the transformer's operating data and temperature data; wherein, the operating data includes winding current and operating power, both of which are acquired by the electrical data acquisition device; the temperature data includes: core insulation temperature, winding insulation temperature and ambient temperature, wherein the core insulation temperature is acquired by the first temperature sensor, the winding insulation temperature is acquired by the second temperature sensor, and the ambient temperature is acquired by the third temperature sensor;

[0013] A processing unit is used to determine heat exchange data based on the temperature data; the heat exchange data includes the core heat flow rate and the winding heat flow rate.

[0014] Based on the operational data, heat source data is determined; the heat source data includes the core heating power and the winding heating power.

[0015] Based on the heat exchange data and the heat source data, an insulation temperature change curve is determined; the insulation temperature change curve includes the core insulation temperature change curve and the winding insulation temperature change curve.

[0016] Based on the insulation temperature change curve, the current carrying capacity of the transformer is determined.

[0017] Thirdly, embodiments of this application provide an electronic device, including: a processor and a memory, the processor being connected to the memory, the memory being used to store a computer program, and the processor being used to execute the computer program stored in the memory, so that the electronic device performs the method as described in the first aspect.

[0018] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that is executed by a processor to implement the method described in the first aspect.

[0019] Fifthly, embodiments of this application provide a computer program product, the computer program product including a non-transitory computer-readable storage medium storing a computer program, the computer program product being operable to cause a computer to perform the method as described in the first aspect.

[0020] Implementing the embodiments of this application has the following beneficial effects:

[0021] In this embodiment, the transformer's operating data and temperature data are obtained by acquiring the core insulation temperature using a first temperature sensor deployed on the transformer core surface, the winding current and operating power using an electrical data acquisition device connected to the windings, the winding insulation temperature using a second temperature sensor deployed on the winding surface, and the ambient temperature using a third temperature sensor deployed on the transformer surface. Then, based on the temperature data, the transformer's heat exchange data is determined, and based on the operating data, the transformer's heat source data is determined. Further, based on the heat exchange data and heat source data, an insulation temperature change curve is determined. Finally, based on the insulation temperature change curve, the transformer's current carrying capacity is determined. Therefore, by combining the transformer's operating data and temperature data, performing heat exchange calculations and heat source data calculations, the insulation temperature change curve of the transformer under the current operating and temperature data can be deduced. Based on the insulation temperature change curve, the transformer's current carrying capacity is determined, which corresponds to the transformer's operating and temperature data, thus improving the accuracy of the current carrying capacity calculation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of a transformer current-carrying capacity determination system provided in an embodiment of this application;

[0024] Figure 2 A flowchart illustrating a method for determining the current carrying capacity of a transformer, provided in an embodiment of this application;

[0025] Figure 3 A functional unit block diagram of a current carrying capacity determination device provided in an embodiment of this application;

[0026] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] The terms "first," "second," and "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0029] In this document, the term "embodiment" means that a particular feature, result, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] First, refer to Figure 1 , Figure 1This is a schematic diagram of a transformer current-carrying capacity determination system provided in an embodiment of this application. Figure 1 As shown, the transformer current carrying capacity determination system includes: a transformer, a first temperature sensor, a second temperature sensor, a third temperature sensor, and an electrical data acquisition unit.

[0031] A transformer is an electrical device that uses the principle of electromagnetic induction to change alternating current voltage. A transformer includes a controller, an iron core, and windings. A first temperature sensor is deployed on the surface of the iron core, and a second temperature sensor is deployed on the surface of the windings, which are connected to an electrical data acquisition unit. The electrical data acquisition unit, the first temperature sensor, and the second temperature sensor are all communicatively connected to the controller. A third temperature sensor is deployed on the surface of the transformer and is also communicatively connected to the controller. Figure 1 The transformer shown is a three-phase transformer. A first temperature sensor is deployed on the surface of the core of each three-phase transformer. In this embodiment, the core can be any one of the cores in the transformer, and the first temperature sensor is the one corresponding to that core. The core is the magnetic circuit part of the transformer, typically made of stacked silicon steel sheets. The core generally has two shapes: core-type and shell-type. In a core-type core, the windings wrap around the core, while in a shell-type core, the core wraps around the windings. Figure 1 The iron core shown is a core-type iron core, with the windings enclosing it. The windings are the circuit part of the transformer, made of insulated wire. The windings include a primary winding and a secondary winding. The primary winding is connected to the power supply. When the current changes, an induced magnetic field is generated in the coil of the primary winding, which in turn induces an electromotive force in the coil of the secondary winding, thus achieving the function of voltage transformation. Figure 1 The transformer shown includes three primary windings and three secondary windings. Each primary winding and each secondary winding is equipped with a second temperature sensor. In this embodiment, the winding can be any one of the three primary windings and three secondary windings, and the second temperature sensor is the one corresponding to that winding. An electrical data acquisition device is connected to any one of the windings via wires and can collect the operating data of any one winding. Transformers can be classified into oil-immersed transformers and dry-type transformers according to their cooling method. In an oil-immersed transformer, the core and windings are immersed in insulating oil, which dissipates heat generated by the transformer to the outside. In a dry-type transformer, the core and windings are not immersed in a liquid medium and rely on natural cooling methods such as air convection or air cooling methods such as installing fans for heat dissipation. This embodiment mainly uses a dry-type transformer as an example for explanation.

[0032] The transformer controller can be a processor chip used for status monitoring, voltage regulation, circuit protection, data processing, and data communication, including: a Central Processing Unit (CPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), etc. The controller can also be an electronic device integrating the aforementioned processor chip, including: a computer, a smartphone, etc. A first temperature sensor is used to collect the core insulation temperature, a second temperature sensor is used to collect the winding insulation temperature, a third temperature sensor is used to collect the ambient temperature, and an electrical data acquisition unit is used to collect the transformer's operating data. In this embodiment, the controller can obtain the core insulation temperature from the first temperature sensor, the winding insulation temperature from the second temperature sensor, the ambient temperature from the third temperature sensor, and the transformer's operating data from the electrical data acquisition unit. Based on the operating data and temperature data, the transformer's current carrying capacity is determined.

[0033] It should be noted that existing methods for determining the current carrying capacity of transformers typically assume that the transformer operates under constant operating and temperature conditions, calculating the current carrying capacity under these constant conditions. However, transformer operating and temperature conditions change constantly, leading to inaccurate current carrying capacity calculations.

[0034] Therefore, in the current carrying capacity determination system of the above-mentioned transformer, the controller in the current carrying capacity determination method of the transformer in this application acquires the transformer's operating data and temperature data; wherein, the operating data includes winding current and operating power, both of which are acquired by an electrical data acquisition device; the temperature data includes: core insulation temperature, winding insulation temperature and ambient temperature, wherein the core insulation temperature is acquired by a first temperature sensor, the winding insulation temperature is acquired by a second temperature sensor, and the ambient temperature is acquired by a third temperature sensor;

[0035] The controller determines heat exchange data based on temperature data; the heat exchange data includes the core heat flow rate and the winding heat flow rate.

[0036] The controller determines the heat source data based on the operating data; the heat source data includes the heating power of the iron core and the heating power of the winding.

[0037] The controller determines the insulation temperature change curve based on heat exchange data and heat source data; the insulation temperature change curve includes the core insulation temperature change curve and the winding insulation temperature change curve.

[0038] The controller determines the transformer's current carrying capacity based on the insulation temperature change curve.

[0039] As can be seen, the current-carrying capacity determination system applied to the aforementioned transformer allows the controller to acquire the transformer's operating data and temperature data. Based on the temperature data, it determines the transformer's heat exchange data, and based on the operating data, it determines the transformer's heat source data. Then, based on the heat exchange data and heat source data, it derives the transformer's insulation temperature change curve. Based on this curve, it determines the transformer's current-carrying capacity, which corresponds to the transformer's operating data and temperature data, thus improving the accuracy of the current-carrying capacity calculation.

[0040] See Figure 2 , Figure 2 This is a flowchart illustrating a method for determining the current carrying capacity of a transformer, provided in an embodiment of this application. The method is applied to a transformer controller. The transformer also includes a core and windings. A first temperature sensor is deployed on the surface of the core, and a second temperature sensor is deployed on the surface of the windings. The windings are connected to an electrical data acquisition unit. The electrical data acquisition unit, the first temperature sensor, and the second temperature sensor are all communicatively connected to the controller. A third temperature sensor is deployed on the surface of the transformer and is communicatively connected to the controller. The method includes, but is not limited to, the following steps:

[0041] 201: Obtain transformer operating data and temperature data.

[0042] In this embodiment, the operating data includes winding current and operating power, both of which are acquired by an electrical data acquisition device. Temperature data includes: core insulation temperature, winding insulation temperature, and ambient temperature. The core insulation temperature is acquired by a first temperature sensor, the winding insulation temperature by a second temperature sensor, and the ambient temperature by a third temperature sensor. The core insulation temperature is the maximum surface temperature of the core when the insulating material maintains its insulation properties; it can also be considered the hot spot temperature of the core. The winding insulation temperature is the maximum surface temperature of the winding when the insulating material maintains its insulation properties; it can also be considered the hot spot temperature of the winding. Optionally, the winding current can be either low-voltage winding current or high-voltage winding current; this application does not limit this. The operating data may also include high-voltage winding voltage and low-voltage winding voltage.

[0043] Optionally, the winding current and operating power collected by the electrical data acquisition unit, the core insulation temperature collected by the first temperature sensor, the winding insulation temperature collected by the second temperature sensor, and the ambient temperature collected by the third temperature sensor may contain outliers or missing values. The controller can perform data cleaning and preprocessing on the collected data, including removing outliers and interpolating missing values. The controller can synchronously store the operating data and temperature data obtained from the electrical data acquisition unit, the first temperature sensor, the second temperature sensor, and the third temperature sensor in a database. The synchronization method can include homogeneous database synchronization or heterogeneous database synchronization. The controller can query the transformer's operating data and temperature data from the database using an aggregated columnar storage index.

[0044] 202: Determine heat exchange data based on temperature data.

[0045] In this embodiment, the heat exchange data includes the core heat flux and the winding heat flux. The core heat flux represents the amount of heat transferred through the core surface per unit time via conduction, convection, radiation, etc. The winding heat flux represents the amount of heat transferred through the winding surface per unit time via conduction, convection, radiation, etc. The heat exchange method of the dry-type transformer is primarily convection heat transfer, and the controller can determine the heat exchange data based on the transformer's temperature data.

[0046] For example, determining heat exchange data based on temperature data may include:

[0047] Obtain the transformer type, core thickness, core heat dissipation area, winding thickness, and winding heat dissipation area;

[0048] Based on temperature data, determine the heat exchange efficiency coefficient corresponding to the transformer type;

[0049] The heat flow rate of the iron core is determined based on the heat exchange efficiency coefficient, the heat dissipation area of ​​the iron core, the thickness of the iron core, the insulation temperature of the iron core, and the ambient temperature.

[0050] The heat flow rate of the winding is determined based on the heat exchange efficiency coefficient, the heat dissipation area of ​​the winding, the winding thickness, the winding insulation temperature, and the ambient temperature.

[0051] In the embodiments of this application, the transformer types include: self-cooled transformers, air-cooled transformers, transformers with air ducts, and transformers without air ducts, etc. Different transformer types correspond to different heat exchange efficiency coefficients. The heat exchange efficiency coefficient is typically between 0.6 and 0.9, used to represent the magnitude of heat exchange efficiency, and is affected by factors such as transformer insulation materials, cooling methods, and ambient humidity. The core heat dissipation area is the sum of the areas of the top of the upper yoke, the side surfaces of the upper and lower yokes, the covered area, and the surface area of ​​the core yoke air ducts. The winding heat dissipation area is the sum of the areas of the horizontal air duct heat dissipation area, the covered area of ​​the internal winding surface, and the vertical air duct heat dissipation area.

[0052] Specifically, the controller first acquires the transformer type, core thickness, core heat dissipation area, winding thickness, and winding heat dissipation area. These parameters are factory-set data stored in a database, from which the controller can directly retrieve the data. Based on the temperature data, the heat exchange efficiency coefficient corresponding to the transformer type can be determined.

[0053] Optionally, the controller first acquires multiple historical temperature data points and multiple historical heat exchange efficiency coefficients corresponding to the transformer type. The historical temperature data includes multiple historical ambient temperatures, multiple historical winding insulation temperatures, and multiple historical core insulation temperatures. Then, it acquires a preset deep learning model, which can be a convolutional neural network model. Using the multiple historical temperature data points as input and the multiple historical heat exchange efficiency coefficients as output, the preset deep learning model is trained to obtain a target deep learning model. Finally, the ambient temperature, winding insulation temperature, and core insulation temperature are input into the target deep learning model to obtain the heat exchange efficiency coefficients.

[0054] It should be noted that heat flow rate can be expressed as the ratio of the differential of heat per unit area and unit thickness to time, or as the product of heat flux density and area. From this, the calculation formulas for core heat flow rate and winding heat flow rate can be derived.

[0055] The controller can determine the core heat flow rate based on the heat exchange efficiency coefficient, core heat dissipation area, core thickness, core insulation temperature, and ambient temperature. Specifically, the core heat flow rate can be determined using the following formula (1):

[0056]

[0057] in, The heat flux of the iron core is represented by α, the heat exchange efficiency coefficient is represented by S0, the heat dissipation area of ​​the iron core is represented by T0, and the insulation temperature of the iron core is represented by T. amb d0 represents the ambient temperature and d0 represents the core thickness.

[0058] Finally, the controller can determine the winding heat flow rate based on the heat exchange efficiency coefficient, winding heat dissipation area, winding thickness, winding insulation temperature and ambient temperature. Specifically, the winding heat flow rate can be determined by the following formula (2):

[0059]

[0060] in, S1 represents the winding heat flow rate, S1 represents the winding heat dissipation area, T1 represents the winding insulation temperature, and d1 represents the winding thickness.

[0061] It can be seen that by obtaining the transformer type, core thickness, core heat dissipation area, winding thickness, and winding heat dissipation area, and based on temperature data, the heat exchange efficiency coefficient corresponding to the transformer type can be determined. Then, based on the heat exchange efficiency coefficient, core heat dissipation area, core thickness, core insulation temperature, and ambient temperature, the core heat flow rate is determined. Finally, based on the heat exchange efficiency coefficient, winding heat dissipation area, winding thickness, winding insulation temperature, and ambient temperature, the winding heat flow rate is determined. Therefore, the corresponding heat exchange data of the transformer can be determined based on the transformer's temperature data, and the insulation temperature change of the transformer can be determined based on the heat exchange data to deduce the current carrying capacity of the transformer under that insulation temperature change, thus improving the accuracy of the current carrying capacity calculation.

[0062] 203: Determine heat source data based on operational data.

[0063] In this embodiment, the heat source data includes the core heating power and the winding heating power. It should be noted that the heat sources generating heat during the operation of a dry-type transformer are the core and the windings. The main reason for heat generation in the core is iron loss, which is the heat loss caused by changes in magnetic flux in the transformer's magnetic circuit, also known as induced loss. The corresponding power loss for iron loss is the core heat loss power. The main reason for heat generation in the windings is copper loss, which is the heat loss caused by the current in the winding coils, also known as resistive loss. The corresponding power loss for copper loss is the winding heat loss power. Therefore, the controller determines the core heat loss power to determine the core heating power. The controller also determines the winding heat loss power based on the operating data to determine the winding heating power.

[0064] For example, determining heat source data based on operational data may include:

[0065] Obtain the various first constituent materials and multiple first masses corresponding to the iron core, and the various second constituent materials and multiple second masses corresponding to the winding;

[0066] Determine the heat capacity of each of the multiple first constituent materials to obtain multiple first heat capacities;

[0067] Determine the proportion of each first mass to the total mass of the multiple first masses to obtain multiple first proportions;

[0068] The first effective heat capacity of the iron core is determined based on multiple first heat capacities and multiple first ratios.

[0069] The no-load power of the transformer is determined based on the operating power, and the no-load power is used as the core loss power.

[0070] The heating power of the iron core is determined based on the first effective heat capacity and the iron core loss power.

[0071] Determine the heat capacity of each of the various second component materials to obtain multiple second heat capacities;

[0072] Determine the proportion of each second mass to the total mass of the multiple second masses to obtain multiple second proportions;

[0073] The second effective heat capacity of the winding is determined based on multiple second heat capacities and multiple second ratios;

[0074] Determine the winding power loss based on the winding current;

[0075] The winding heating power is determined based on the second effective heat capacity and the winding loss power.

[0076] In the embodiments of this application, multiple first constituent materials correspond one-to-one with multiple first masses, and multiple second constituent materials correspond one-to-one with multiple second masses.

[0077] Specifically, the controller first acquires the various first constituent materials corresponding to the iron core and the various first masses corresponding to these first constituent materials. For example, the constituent materials of the iron core are typically the conductor portion, the internal insulation portion, and the external insulating resin. It then acquires the various second constituent materials corresponding to the winding and the various second masses corresponding to these second constituent materials. For example, the constituent materials of the winding are typically the metal conductor portion, the internal insulating paper portion, and the external insulating resin. The various first constituent materials, the various first masses, the various second constituent materials, and the various second masses are all factory parameters of the transformer, stored in a database, from which the controller can retrieve them.

[0078] Then, the controller determines the heat capacity of each of the multiple first component materials, obtaining multiple first heat capacities. It should be noted that the first heat capacity corresponding to each first component material is an intrinsic property of the material itself; that is, the correspondence between the first component material and the first heat capacity can be preset based on the material's intrinsic properties. Next, the controller determines the total mass of the multiple first masses, and uses the ratio of each first mass to the total mass of the multiple first masses as the first proportion of the first component material corresponding to that first mass, obtaining multiple first proportions. Finally, the controller multiplies the first heat capacity corresponding to each of the multiple first component materials with the first proportion, obtaining multiple first products, and uses the sum of the multiple first products as the first effective heat capacity of the iron core.

[0079] Furthermore, the controller determines the transformer's no-load power based on the operating power. It can be understood that the transformer's no-load power can be approximated as iron loss. No-load power is a factory parameter of the transformer and is affected by operating voltage fluctuations. The mapping relationship between no-load power and operating voltage can be preset based on actual test results. The controller can determine the transformer's operating voltage based on the transformer's operating power and winding current, and then determine the transformer's no-load power based on the operating voltage, using the no-load power as the core loss power. Finally, the controller can determine the core heating power based on the core loss power and the first effective heat capacity. The mapping relationship between core loss power, the first effective heat capacity, and the core heating power can be preset based on actual test results.

[0080] Optionally, after determining the first effective heat capacity of the iron core, the controller can also multiply the total mass of multiple first masses by the first effective heat capacity and then multiply it by the heat flow rate of the iron core to obtain the heating power of the iron core.

[0081] Then, the controller determines the heat capacity of each of the multiple second component materials, obtaining multiple second heat capacities. It should be noted that the second heat capacity corresponding to each second component material is an intrinsic property of the material itself; that is, the correspondence between the second component material and the second heat capacity can be preset based on the material's intrinsic properties. Next, the controller determines the total mass of the multiple second masses, and uses the ratio of each second mass to the total mass of the multiple second masses as the second proportion of the second component material corresponding to that second mass, obtaining multiple second proportions. Finally, the controller multiplies the second heat capacity corresponding to each of the multiple second component materials by the second proportion, obtaining multiple second products, and the sum of the multiple second products is taken as the second effective heat capacity of the winding.

[0082] Furthermore, the controller can determine the winding loss power based on the transformer winding current.

[0083] For example, determining winding power loss based on winding current may include:

[0084] Obtain the corresponding resistance value, temperature coefficient of resistance, and factory winding insulation temperature of the winding;

[0085] The winding loss power is determined by the following formula (3):

[0086] P Cu =I 2 R Cu [1+TCR(T Cu0 -T Cu )] Formula (3)

[0087] Among them, P Cu R represents the winding power loss, I represents the winding current, and R represents the winding current. Cu TCR represents the resistance value, and T represents the temperature coefficient of resistance. Cu0 Indicates the factory winding insulation temperature, T Cu This indicates the winding insulation temperature. The temperature coefficient of resistance represents the ratio of the change in winding insulation temperature to the actual increase in winding insulation temperature per unit temperature.

[0088] Specifically, the controller first obtains the resistance value, temperature coefficient of resistance, and factory winding insulation temperature of the winding. These parameters are factory parameters of the transformer and are stored in a database, from which the controller can retrieve them. Then, the winding loss power is determined using formula (3), which allows the winding heating power to be determined based on the winding loss power. This enables the winding insulation temperature to be extrapolated, thus determining the transformer's current carrying capacity and improving the accuracy of the current carrying capacity calculation.

[0089] Finally, the controller can determine the winding heating power based on the winding loss power and the second effective heat capacity. The mapping relationship between the winding loss power, the second effective heat capacity, and the winding heating power can be preset according to the actual test results.

[0090] Optionally, after determining the second effective heat capacity of the winding, the controller can also multiply the total mass of the multiple second masses by the second effective heat capacity and then multiply it by the winding heat flow rate to obtain the winding heating power.

[0091] As can be seen, the controller can determine the first effective heat capacity of the core based on multiple first heat capacities and multiple first masses corresponding to various constituent materials in the core. Then, it determines the no-load power of the transformer based on the operating power, using the no-load power as the core loss power. Based on the first effective heat capacity and the core loss power, the core heating power is determined. Next, based on multiple second heat capacities and multiple second masses corresponding to various second constituent materials of the winding, the second effective heat capacity of the winding is determined. Further, the winding loss power is determined based on the winding current. Based on the second effective heat capacity and the winding loss power, the winding heating power can be determined. Thus, the heat source data of the transformer can be determined, and the insulation temperature of the transformer can be extrapolated based on the heat source data. Finally, the current carrying capacity of the transformer is determined. This current carrying capacity fully considers the influence of the transformer's temperature change, improving the accuracy of the current carrying capacity calculation.

[0092] 204: Based on heat exchange data and heat source data, determine the insulation temperature change curve.

[0093] In this embodiment, the insulation temperature variation curves include the core insulation temperature variation curve and the winding insulation temperature variation curve. The core insulation temperature variation curve represents the change of core insulation temperature with temperature, and the winding insulation temperature variation curve represents the change of winding insulation temperature with temperature. It should be noted that a heat balance relationship corresponding to the transformer can be established based on heat exchange data and heat source data, thereby determining the relationship between the core insulation temperature and winding insulation temperature variations in the transformer, and thus determining the core insulation temperature variation curve and the winding insulation temperature variation curve.

[0094] For example, determining the insulation temperature change curve based on heat exchange data and heat source data may include:

[0095] Obtain the temperature variation limit value of the transformer;

[0096] Based on the core heat flux and core heating power, a first heat balance relationship is established; based on the first heat balance relationship, the temperature change relationship of the core insulation is determined.

[0097] Based on the temperature change limit and the relationship between the core insulation temperature change, the core insulation temperature is extrapolated, and multiple expected core insulation temperatures are obtained.

[0098] Curve fitting was performed on multiple expected core insulation temperatures to obtain core insulation temperature variation curves;

[0099] A second heat balance relationship is established based on the winding heat flow rate and the winding heating power; the relationship of winding insulation temperature change is determined based on the second heat balance relationship.

[0100] Based on the temperature change limit and the relationship between the winding insulation temperature change, the winding insulation temperature is extrapolated to obtain multiple expected winding insulation temperatures;

[0101] Curve fitting was performed on multiple expected winding insulation temperatures to obtain winding insulation temperature variation curves.

[0102] In this embodiment, the temperature change limit value is a factory parameter of the transformer, representing the maximum allowable temperature rise of the transformer during operation, and is stored in a database. Specifically, the controller can obtain the temperature change limit value of the transformer from the database.

[0103] Then, the controller can establish a first heat balance relationship based on the core heat flux and the core heating power. Based on the first heat balance relationship, the core insulation temperature change relationship can be determined, which can be simplified and expressed by the following formula (4):

[0104]

[0105] Where dt represents the derivative with respect to time, C Fe The first effective heat capacity is represented by m. Fe The first mass represents the total mass of multiple first masses, ΔT0 represents the change in the core insulation temperature, and P0 represents the core heating power.

[0106] Furthermore, based on the relationship between the temperature change limit and the core insulation temperature change, the controller extrapolates the core insulation temperature, estimating multiple expected core insulation temperatures as the current core insulation temperature changes to the temperature change limit. Curve fitting is then performed on these multiple expected core insulation temperatures to obtain the core insulation temperature change curve.

[0107] Then, the controller establishes a second heat balance relationship based on the winding heat flow rate and the winding heating power. Based on the second heat balance relationship, the winding insulation temperature change relationship can be determined, which can be simplified and expressed by the following formula (5):

[0108]

[0109] Among them, C Cu Indicates the second effective heat capacity, m Cu The total mass of multiple second masses is represented by ΔT1, which represents the change in winding insulation temperature, and P1 represents the heating power of the winding.

[0110] Furthermore, based on the relationship between the temperature change limit and the winding insulation temperature change, the controller extrapolates the winding insulation temperature, estimating multiple expected winding insulation temperatures as the current winding insulation temperature changes to the temperature change limit. Curve fitting is then performed on these multiple expected winding insulation temperatures to obtain the winding insulation temperature change curve.

[0111] It can be seen that a first heat balance relationship is established by using the core heat flux and core heating power. Based on this first heat balance relationship, the core insulation temperature variation relationship is determined. The core insulation temperature can then be extrapolated based on the transformer's temperature variation limits and the core insulation temperature variation relationship, resulting in multiple expected core insulation temperatures. By curve fitting these multiple expected core insulation temperatures, a core insulation temperature variation curve can be obtained. Then, a second heat balance relationship is established based on the winding heat flux and winding heating power. Based on this second heat balance relationship, the winding insulation temperature variation relationship can be extrapolated, resulting in multiple expected winding insulation temperatures. By curve fitting these multiple expected winding insulation temperatures, a winding insulation temperature variation curve can be obtained. Therefore, based on the core insulation temperature variation curve and the winding insulation temperature variation curve, the transformer's current carrying capacity can be determined. This current carrying capacity fully considers the changes in core and winding insulation temperatures, improving the accuracy of the current carrying capacity calculation.

[0112] 205: Determine the current carrying capacity of the transformer based on the insulation temperature change curve.

[0113] In this embodiment, the current carrying capacity of the transformer may include the current carrying capacity corresponding to the thermal equilibrium point and / or the current carrying capacity corresponding to the critical point. The thermal equilibrium point is the sample point corresponding to the moment when both the core heat flux and the winding heat flux are 0, and the critical point is the sample point where both the core insulation temperature and the winding insulation temperature reach the maximum insulation temperature and the maximum insulation temperature change value corresponding to the transformer's heat resistance level.

[0114] For example, when the transformer's current-carrying capacity includes the current-carrying capacity corresponding to the thermal equilibrium point, determining the transformer's current-carrying capacity based on the insulation temperature change curve may include:

[0115] Obtain multiple first sample points with a slope of 0 and multiple first time points in the temperature change curve of the iron core insulation;

[0116] Based on multiple first moments, multiple second sample points are obtained from the winding insulation temperature change curve;

[0117] Determine the slope of multiple second sample points in the winding insulation temperature change curve, and take the second sample point with a slope of 0 as the thermal equilibrium point.

[0118] Obtain the thermal equilibrium point limit value;

[0119] Based on the thermal balance point limit value, determine the maximum winding heating power corresponding to the thermal balance point;

[0120] Determine the current carrying capacity based on the maximum winding heating power.

[0121] In the embodiments of this application, multiple first sample points correspond one-to-one with multiple first moments. It should be noted that at the thermal equilibrium point, the heat flowing into the transformer plus the heat generated by the transformer itself equals the heat flowing out of the transformer; therefore, the transformer is in a thermally steady state, and the temperature of any node does not change with time. At this point, the dry-type transformer operates in a stable state, and as long as the core insulation temperature and winding insulation temperature in the transformer do not exceed the temperature corresponding to the thermal equilibrium point, it can operate stably for a long time.

[0122] Specifically, the controller first determines the slope corresponding to each sample point in the core insulation temperature change curve, and takes the sample point with a slope of 0 as the first sample point, thus obtaining multiple first sample points. It then acquires multiple first time points corresponding to these first sample points. Next, based on these multiple first time points, it acquires multiple second sample points from the winding insulation temperature change curve, and determines the slope corresponding to each of these second sample points in the winding insulation temperature change curve. Further, the controller takes the point with a slope of 0 among the multiple second sample points as the thermal equilibrium point. It is understood that there may be multiple second sample points with a slope of 0 among the multiple second sample points. The controller acquires multiple second time points corresponding to these second sample points with a slope of 0, and takes the second sample point with the smallest slope of 0 at the second time point as the thermal equilibrium point.

[0123] Furthermore, the controller can retrieve the thermal equilibrium point limit value from the database. This limit value restricts the variation in the winding insulation temperature curve, effectively limiting the insulation temperature change to zero. Based on the thermal equilibrium point limit value, the controller can apply the forced convergence theorem to determine the maximum winding heating power corresponding to the thermal equilibrium point, and then determine the maximum winding loss power based on the maximum winding heating power. Finally, the controller can determine the operating current corresponding to the maximum winding loss power as the current carrying capacity corresponding to the thermal equilibrium point, i.e., the transformer's current carrying capacity.

[0124] It can be seen that by determining multiple first sample points with a slope of 0 on the core insulation temperature change curve, corresponding to multiple first moments, and obtaining multiple second sample points on the winding insulation temperature change curve based on these first moments, the second sample point with a slope of 0 is taken as the thermal equilibrium point. Then, based on the thermal equilibrium point limit, the maximum winding heating power corresponding to the thermal equilibrium point is determined, and the current carrying capacity is determined based on the maximum winding heating power. By operating the transformer at the current carrying capacity corresponding to the thermal equilibrium point, insulation degradation can be reduced, dielectric strength, coil structural integrity can be improved, winding noise can be reduced, heat transfer can be improved, and partial discharge can be reduced, ensuring the stable operation of the dry-type transformer and extending its service life. Simultaneously, this current carrying capacity considers both core insulation temperature changes and winding insulation temperature changes, improving the accuracy of the current carrying capacity calculation.

[0125] For example, when the transformer's current-carrying capacity includes the current-carrying capacity corresponding to the critical point, determining the transformer's current-carrying capacity based on the insulation temperature change curve may include:

[0126] To determine the heat resistance rating of the insulation material in a transformer;

[0127] Based on the heat resistance rating, determine the maximum insulation temperature and the maximum insulation temperature variation;

[0128] Obtain sample points in the core insulation temperature change curve where the core insulation temperature is equal to the maximum insulation temperature and the core insulation temperature change value is equal to the maximum insulation temperature change value, and obtain at least one third sample point.

[0129] Obtain at least one fourth sample point corresponding to at least one third sample point from the winding insulation temperature change curve;

[0130] The sample point in which the winding insulation temperature is equal to the maximum insulation temperature and the change value of the winding insulation temperature is equal to the change value of the maximum insulation temperature is taken as the critical point.

[0131] Determine the maximum winding heat flux corresponding to the critical point;

[0132] The current carrying capacity is determined based on the maximum winding heat flux.

[0133] In this embodiment, the critical point is related to the heat resistance grade of the insulation material in the transformer. The mapping relationship between the heat resistance grade and the maximum insulation temperature and its variation value can be preset based on actual test results. To ensure the safety of the dry-type transformer during operation, the core insulation temperature and winding insulation temperature of the dry-type transformer must never exceed the maximum insulation temperature and its variation value.

[0134] Specifically, the controller first obtains the heat resistance rating of the insulation material in the transformer. This heat resistance rating is a factory parameter of the transformer and is stored in a database, from which the controller can directly retrieve the information. Based on the heat resistance rating, the maximum insulation temperature and the maximum insulation temperature variation of the transformer can be determined.

[0135] Then, the controller will obtain sample points from the core insulation temperature change curve where the core insulation temperature is equal to the maximum insulation temperature and the core insulation temperature change value is equal to the maximum insulation temperature change value, thus obtaining at least one third sample point. The core insulation temperature change value of each sample point in the core insulation temperature change curve can be represented by the derivative of the core insulation temperature corresponding to that sample point.

[0136] Furthermore, the controller will obtain at least one fourth sample point corresponding to at least one third sample point from the winding insulation temperature change curve based on at least one time corresponding to at least one third sample point. The sample point among the at least one fourth sample point where the winding insulation temperature is equal to the maximum insulation temperature and the winding insulation temperature change value is equal to the maximum insulation temperature change value will be designated as a critical point. The winding insulation temperature change value of each sample point in the winding insulation temperature change curve can be expressed as the derivative of the winding insulation temperature corresponding to that sample point. It is understood that there may be multiple sample points among the at least one fourth sample point where the winding insulation temperature is equal to the maximum insulation temperature and the winding insulation temperature change value is equal to the maximum insulation temperature change value; the controller will designate the sample point with the smallest corresponding time among these multiple sample points as the critical point.

[0137] Furthermore, the controller determines the maximum winding heat flux based on the winding insulation temperature corresponding to the critical point. Based on the maximum winding heat flux, it determines the maximum winding heating power corresponding to the critical point. Based on the maximum winding heating power corresponding to the critical point, it determines the maximum winding loss power corresponding to the critical point, and based on the maximum winding loss power corresponding to the critical point, it determines the transformer's current carrying capacity at the critical point.

[0138] Therefore, by identifying sample points in the core insulation temperature variation curve where the core insulation temperature equals the maximum insulation temperature and the change in core insulation temperature equals the maximum insulation temperature change, and sample points in the winding insulation temperature variation curve where the winding insulation temperature equals the maximum insulation temperature and the change in winding insulation temperature equals the maximum insulation temperature change, the critical points can be obtained. Based on the maximum winding heat flux corresponding to the critical point, the current carrying capacity of the transformer at the critical point can be determined. This current carrying capacity takes into account both the core insulation temperature variation and the winding insulation temperature variation, improving the accuracy of the current carrying capacity calculation.

[0139] As can be seen in this embodiment, the transformer's operating data and temperature data are obtained by acquiring the core insulation temperature using a first temperature sensor deployed on the transformer core surface, the winding current and operating power using an electrical data acquisition device connected to the windings, the winding insulation temperature using a second temperature sensor deployed on the winding surface, and the ambient temperature using a third temperature sensor deployed on the transformer surface. Then, based on the temperature data, the transformer's heat exchange data is determined, and based on the operating data, the transformer's heat source data is determined. Further, based on the heat exchange data and heat source data, the insulation temperature change curve is determined. Finally, based on the insulation temperature change curve, the transformer's current carrying capacity is determined. Therefore, by combining the transformer's operating data and temperature data, performing heat exchange calculations and heat source data calculations, the insulation temperature change curve of the transformer under the current operating and temperature data can be deduced. Based on the insulation temperature change curve, the transformer's current carrying capacity is determined, which corresponds to the transformer's operating and temperature data, thus improving the accuracy of the current carrying capacity calculation.

[0140] See Figure 3 , Figure 3 This is a functional unit block diagram of a current-carrying capacity determination device provided in an embodiment of this application. The current-carrying capacity determination device 300 is applied to a transformer controller. The transformer also includes an iron core and windings. A first temperature sensor is deployed on the surface of the iron core, and a second temperature sensor is deployed on the surface of the windings. The windings are connected to an electrical data acquisition unit. The electrical data acquisition unit, the first temperature sensor, and the second temperature sensor are all communicatively connected to the controller. A third temperature sensor is deployed on the surface of the transformer and is communicatively connected to the controller. The current-carrying capacity determination device 300 includes an acquisition unit 301 and a processing unit 302.

[0141] The acquisition unit 301 is used to acquire the transformer's operating data and temperature data. The operating data includes winding current and operating power, both of which are acquired by an electrical data acquisition device. The temperature data includes core insulation temperature, winding insulation temperature, and ambient temperature. The core insulation temperature is acquired by a first temperature sensor, the winding insulation temperature is acquired by a second temperature sensor, and the ambient temperature is acquired by a third temperature sensor.

[0142] Processing unit 302 is used to determine heat exchange data based on temperature data; the heat exchange data includes core heat flow rate and winding heat flow rate;

[0143] Based on operational data, heat source data is determined; heat source data includes core heating power and winding heating power.

[0144] Based on heat exchange data and heat source data, the insulation temperature change curve is determined; the insulation temperature change curve includes the core insulation temperature change curve and the winding insulation temperature change curve.

[0145] The current carrying capacity of the transformer is determined based on the insulation temperature change curve.

[0146] In one possible embodiment, in determining heat exchange data based on temperature data, processing unit 302 is specifically configured to:

[0147] Obtain the transformer type, core thickness, core heat dissipation area, winding thickness, and winding heat dissipation area;

[0148] Based on temperature data, determine the heat exchange efficiency coefficient corresponding to the transformer type;

[0149] The heat flow rate of the iron core is determined based on the heat exchange efficiency coefficient, the heat dissipation area of ​​the iron core, the thickness of the iron core, the insulation temperature of the iron core, and the ambient temperature.

[0150] The heat flow rate of the winding is determined based on the heat exchange efficiency coefficient, the heat dissipation area of ​​the winding, the winding thickness, the winding insulation temperature, and the ambient temperature.

[0151] In one possible embodiment, in determining heat source data based on operational data, processing unit 302 is specifically configured to:

[0152] Obtain the various first constituent materials and multiple first masses corresponding to the iron core, the various second constituent materials and multiple second masses corresponding to the winding, and the various first constituent materials and multiple first masses correspond one-to-one, and the various second constituent materials and multiple second masses correspond one-to-one;

[0153] Determine the heat capacity of each of the multiple first constituent materials to obtain multiple first heat capacities;

[0154] Determine the proportion of each first mass to the total mass of the multiple first masses to obtain multiple first proportions;

[0155] The first effective heat capacity of the iron core is determined based on multiple first heat capacities and multiple first ratios.

[0156] The no-load power of the transformer is determined based on the operating power, and the no-load power is used as the core loss power.

[0157] The heating power of the iron core is determined based on the first effective heat capacity and the iron core loss power.

[0158] Determine the heat capacity of each of the various second component materials to obtain multiple second heat capacities;

[0159] Determine the proportion of each second mass to the total mass of the multiple second masses to obtain multiple second proportions;

[0160] The second effective heat capacity of the winding is determined based on multiple second heat capacities and multiple second ratios;

[0161] Determine the winding power loss based on the winding current;

[0162] The winding heating power is determined based on the second effective heat capacity and the winding loss power.

[0163] In one possible embodiment, in determining the winding loss power based on the winding current, the processing unit 302 is specifically configured to:

[0164] Obtain the corresponding resistance value, temperature coefficient of resistance, and factory winding insulation temperature of the winding; the temperature coefficient of resistance represents the ratio of the change in winding insulation temperature to the actual winding insulation temperature when the winding insulation temperature increases by one unit temperature.

[0165] The winding loss power is determined by the following formula:

[0166] P Cu =I 2 R Cu [1+TCR(T Cu0 -T Cu )]

[0167] Among them, P Cu R represents the winding power loss, I represents the winding current, and R represents the winding current. Cu TCR represents the resistance value, and T represents the temperature coefficient of resistance. Cu0 Indicates the factory winding insulation temperature, T Cu This indicates the winding insulation temperature.

[0168] In one possible embodiment, in determining the insulation temperature change curve based on heat exchange data and heat source data, the processing unit 302 is specifically used for:

[0169] Obtain the temperature variation limit value of the transformer;

[0170] Based on the core heat flux and core heating power, a first heat balance relationship is established; based on the first heat balance relationship, the temperature change relationship of the core insulation is determined.

[0171] Based on the temperature change limit and the relationship between the core insulation temperature change, the core insulation temperature is extrapolated, and multiple expected core insulation temperatures are obtained.

[0172] Curve fitting was performed on multiple expected core insulation temperatures to obtain core insulation temperature variation curves; a second heat balance relationship was established based on winding heat flow rate and winding heating power.

[0173] Based on the second heat balance relationship, the relationship of winding insulation temperature change is determined;

[0174] Based on the temperature change limit and the relationship between the winding insulation temperature change, the winding insulation temperature is extrapolated to obtain multiple expected winding insulation temperatures;

[0175] Curve fitting was performed on multiple expected winding insulation temperatures to obtain winding insulation temperature variation curves.

[0176] In one possible embodiment, when the transformer's current-carrying capacity includes the current-carrying capacity corresponding to the thermal equilibrium point, the processing unit 302, in determining the transformer's current-carrying capacity based on the insulation temperature change curve, is specifically used for:

[0177] Obtain multiple first sample points with a slope of 0 and multiple first time moments in the temperature change curve of the iron core insulation; the multiple first sample points correspond one-to-one with the multiple first time moments;

[0178] Based on multiple first moments, multiple second sample points are obtained from the winding insulation temperature change curve;

[0179] Determine the slope of multiple second sample points in the winding insulation temperature change curve, and take the second sample point with a slope of 0 as the thermal equilibrium point.

[0180] Obtain the thermal equilibrium point limit value;

[0181] Based on the thermal balance point limit value, determine the maximum winding heating power corresponding to the thermal balance point;

[0182] Determine the current carrying capacity based on the maximum winding heating power.

[0183] In one possible embodiment, when the transformer's current-carrying capacity includes the current-carrying capacity corresponding to the critical point, the processing unit 302, based on the insulation temperature change curve, determines the transformer's current-carrying capacity. Specifically, this is used for:

[0184] To determine the heat resistance rating of the insulation material in a transformer;

[0185] Based on the heat resistance rating, determine the maximum insulation temperature and the maximum insulation temperature variation;

[0186] Obtain sample points in the core insulation temperature change curve where the core insulation temperature is equal to the maximum insulation temperature and the core insulation temperature change value is equal to the maximum insulation temperature change value, and obtain at least one third sample point.

[0187] Obtain at least one fourth sample point corresponding to at least one third sample point from the winding insulation temperature change curve;

[0188] The sample point in which the winding insulation temperature is equal to the maximum insulation temperature and the change value of the winding insulation temperature is equal to the change value of the maximum insulation temperature is taken as the critical point.

[0189] Determine the maximum winding heat flux corresponding to the critical point;

[0190] The current carrying capacity is determined based on the maximum winding heat flux.

[0191] See Figure 4 , Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 400 includes a transceiver 401, a processor 402, and a memory 403. These are connected via a bus 404. The memory 403 stores computer programs and data, and can transmit data stored in the memory 403 to the processor 402. The electronic device 400 can be a current carrying capacity determination device 300. The electronic device 400 can also be a controller in any of the above embodiments.

[0192] Processor 402 is used to read the computer program in memory 403 and perform the following operations:

[0193] Obtain transformer operating data and temperature data;

[0194] Based on temperature data, heat exchange data is determined; heat exchange data includes core heat flow rate and winding heat flow rate.

[0195] Based on operational data, determine the heat source data;

[0196] Based on heat exchange data and heat source data, the insulation temperature change curve was determined;

[0197] The current carrying capacity of the transformer is determined based on the insulation temperature change curve.

[0198] The above primarily describes the solutions of the embodiments of this application from the perspective of the method execution process. It is understood that, in order to achieve the above functions, the electronic device includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments provided herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0199] This application also provides a computer-readable storage medium storing a computer program that is executed by a processor to implement some or all of the steps of any of the methods described in the above method embodiments.

[0200] This application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of any of the methods described in the above method embodiments.

[0201] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0202] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0203] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical or other forms.

[0204] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0205] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software program module.

[0206] If the integrated unit is implemented as a software program module and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0207] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: flash drive, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0208] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for determining the current-carrying capacity of a transformer, characterized in that, A controller for a transformer, the transformer further comprising an iron core and windings, wherein a first temperature sensor is deployed on the surface of the iron core, a second temperature sensor is deployed on the surface of the windings, and the windings are connected to an electrical data acquisition unit; The electrical data acquisition unit, the first temperature sensor, and the second temperature sensor are all communicatively connected to the controller. A third temperature sensor is deployed on the surface of the transformer, and the third temperature sensor is communicatively connected to the controller; the method includes: The transformer's operating data and temperature data are acquired; wherein, the operating data includes winding current and operating power, both of which are acquired by the electrical data acquisition device; the temperature data includes: core insulation temperature, winding insulation temperature and ambient temperature, wherein the core insulation temperature is acquired by the first temperature sensor, the winding insulation temperature is acquired by the second temperature sensor, and the ambient temperature is acquired by the third temperature sensor; Based on the temperature data, heat exchange data is determined; the heat exchange data includes the core heat flow rate and the winding heat flow rate. Based on the operational data, heat source data is determined; the heat source data includes the core heating power and the winding heating power. Based on the heat exchange data and the heat source data, an insulation temperature change curve is determined; the insulation temperature change curve includes the core insulation temperature change curve and the winding insulation temperature change curve. Based on the insulation temperature change curve, the current carrying capacity of the transformer is determined; The step of determining the insulation temperature change curve based on the heat exchange data and the heat source data includes: Obtain the temperature variation limit value of the transformer; Based on the core heat flux and the core heating power, a first heat balance relationship is established; based on the first heat balance relationship, the core insulation temperature change relationship is determined. Based on the temperature change limit and the relationship between the core insulation temperature change, the core insulation temperature is extrapolated to obtain multiple expected core insulation temperatures. Curve fitting is performed on the multiple expected core insulation temperatures to obtain the core insulation temperature change curves; a second heat balance relationship is established based on the winding heat flow rate and the winding heating power. Based on the second heat balance relationship, the winding insulation temperature change relationship is determined; Based on the temperature change limit and the relationship between the winding insulation temperature change, the winding insulation temperature is extrapolated to obtain multiple expected winding insulation temperatures; Curve fitting is performed on the multiple expected winding insulation temperatures to obtain the winding insulation temperature variation curves.

2. The method according to claim 1, characterized in that, The step of determining heat exchange data based on the temperature data includes: Obtain the transformer type, core thickness, core heat dissipation area, winding thickness, and winding heat dissipation area of ​​the transformer. Based on the temperature data, determine the heat exchange efficiency coefficient corresponding to the transformer type; The heat flow rate of the iron core is determined based on the heat exchange efficiency coefficient, the heat dissipation area of ​​the iron core, the thickness of the iron core, the insulation temperature of the iron core, and the ambient temperature. The heat flow rate of the winding is determined based on the heat exchange efficiency coefficient, the heat dissipation area of ​​the winding, the thickness of the winding, the insulation temperature of the winding, and the ambient temperature.

3. The method according to claim 1 or 2, characterized in that, The determination of heat source data based on the operational data includes: Obtain multiple first constituent materials and multiple first masses corresponding to the iron core, multiple second constituent materials and multiple second masses corresponding to the winding, wherein the multiple first constituent materials correspond one-to-one with the multiple first masses, and the multiple second constituent materials correspond one-to-one with the multiple second masses; Determine the heat capacity of each of the multiple first component materials to obtain multiple first heat capacities; Determine the proportion of each of the plurality of first masses to the total mass of the plurality of first masses to obtain a plurality of first proportions; The first effective heat capacity of the iron core is determined based on the plurality of first heat capacities and the plurality of first ratios; The no-load power of the transformer is determined based on the operating power, and the no-load power is used as the core loss power. The heating power of the iron core is determined based on the first effective heat capacity and the core loss power. Determine the heat capacity of each of the various second component materials to obtain multiple second heat capacities; Determine the proportion of each of the plurality of second masses to the total mass of the plurality of second masses to obtain a plurality of second proportions; The second effective heat capacity of the winding is determined based on the plurality of second heat capacities and the plurality of second ratios; Based on the winding current, determine the winding power loss; The heating power of the winding is determined based on the second effective heat capacity and the winding loss power.

4. The method according to claim 3, characterized in that, Determining the winding power loss based on the winding current includes: Obtain the resistance value, temperature coefficient of resistance, and factory winding insulation temperature of the winding; the temperature coefficient of resistance represents the ratio of the change in winding insulation temperature to the actual winding insulation temperature when the winding insulation temperature increases by one unit temperature. The winding loss power is determined by the following formula: in, I represents the winding power loss, and I represents the winding current. The resistance value is represented by TCR, which represents the temperature coefficient of resistance. This indicates the factory-issued winding insulation temperature. This indicates the insulation temperature of the winding.

5. The method according to claim 1 or 2, characterized in that, When the current-carrying capacity of the transformer includes the current-carrying capacity corresponding to the thermal equilibrium point, determining the current-carrying capacity of the transformer based on the insulation temperature change curve includes: Acquire multiple first sample points with a slope of 0 and multiple first time moments in the temperature change curve of the iron core insulation; the multiple first sample points correspond one-to-one with the multiple first time moments. Based on the multiple first moments, multiple second sample points are obtained from the winding insulation temperature change curve; Determine the slope of the plurality of second sample points in the winding insulation temperature change curve, and take the second sample point with a slope of 0 as the thermal equilibrium point; Obtain the thermal equilibrium point limit value; Based on the thermal balance point limit value, determine the maximum winding heating power corresponding to the thermal balance point; The current carrying capacity is determined based on the maximum winding heating power.

6. The method according to claim 1 or 2, characterized in that, When the current-carrying capacity of the transformer includes the current-carrying capacity corresponding to the critical point, determining the current-carrying capacity of the transformer based on the insulation temperature change curve includes: Obtain the heat resistance rating of the insulation material in the transformer; Based on the heat resistance rating, determine the maximum insulation temperature and the maximum insulation temperature variation. Obtain at least one third sample point from the core insulation temperature change curve where the core insulation temperature is equal to the maximum insulation temperature and the core insulation temperature change value is equal to the maximum insulation temperature change value. Obtain at least one fourth sample point corresponding to the at least one third sample point from the winding insulation temperature change curve; The critical point is defined as the sample point in the at least one fourth sample point where the winding insulation temperature is equal to the maximum insulation temperature and the change value of the winding insulation temperature is equal to the change value of the maximum insulation temperature. Determine the maximum winding heat flux corresponding to the critical point; The current carrying capacity is determined based on the maximum winding heat flux.

7. A current carrying capacity determination device, characterized in that, A controller for a transformer, the transformer further comprising an iron core and windings, wherein a first temperature sensor is deployed on the surface of the iron core, a second temperature sensor is deployed on the surface of the windings, and the windings are connected to an electrical data acquisition unit; The electrical data acquisition unit, the first temperature sensor, and the second temperature sensor are all communicatively connected to the controller. A third temperature sensor is deployed on the surface of the transformer, and the third temperature sensor is communicatively connected to the controller; the device includes: The acquisition unit is used to acquire the transformer's operating data and temperature data; wherein, the operating data includes winding current and operating power, both of which are acquired by the electrical data acquisition device; the temperature data includes: core insulation temperature, winding insulation temperature and ambient temperature, wherein the core insulation temperature is acquired by the first temperature sensor, the winding insulation temperature is acquired by the second temperature sensor, and the ambient temperature is acquired by the third temperature sensor; A processing unit is used to determine heat exchange data based on the temperature data; the heat exchange data includes the core heat flow rate and the winding heat flow rate. Based on the operational data, heat source data is determined; the heat source data includes the core heating power and the winding heating power. Based on the heat exchange data and the heat source data, an insulation temperature change curve is determined; the insulation temperature change curve includes the core insulation temperature change curve and the winding insulation temperature change curve. Based on the insulation temperature change curve, the current carrying capacity of the transformer is determined; The step of determining the insulation temperature change curve based on the heat exchange data and the heat source data includes: Obtain the temperature variation limit value of the transformer; Based on the core heat flux and the core heating power, a first heat balance relationship is established; based on the first heat balance relationship, the core insulation temperature change relationship is determined. Based on the temperature change limit and the relationship between the core insulation temperature change, the core insulation temperature is extrapolated to obtain multiple expected core insulation temperatures. Curve fitting is performed on the multiple expected core insulation temperatures to obtain the core insulation temperature change curves; a second heat balance relationship is established based on the winding heat flow rate and the winding heating power. Based on the second heat balance relationship, the winding insulation temperature change relationship is determined; Based on the temperature change limit and the relationship between the winding insulation temperature change, the winding insulation temperature is extrapolated to obtain multiple expected winding insulation temperatures; Curve fitting is performed on the multiple expected winding insulation temperatures to obtain the winding insulation temperature variation curves.

8. An electronic device, characterized in that, include: A processor and a memory, the processor being connected to the memory, the memory being used to store a computer program, and the processor being used to execute the computer program stored in the memory to cause the electronic device to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is executed by a processor to implement the method as described in any one of claims 1-6.

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