Selection of transformer model

Abstract

A method (100, 200) for selecting a transformer model, the method being performed by a computer system (400), the method comprising: - modelling a transformer model comprising a coil (10) configured to support an electric field; - determining a frequency interval comprising a set of resonant frequencies of the transformer model; - calculating a maximum electric field acting on the coil (10) when a voltage oscillating over the frequency interval passes through the transformer model; - comparing the maximum electric field with a maximum allowable electric field value; and - selecting the transformer model in dependence on the comparison made previously.

Description

Technical Field

[0001] This disclosure relates to a method for selecting a transformer model. It also relates to a computer program comprising instructions for performing the method for selecting a transformer model, and further to a computer system. Finally, this disclosure relates to a method for manufacturing a transformer. Background Technology

[0002] Typically, electrical equipment has a transformer for regulating the voltage value of the current flowing in the equipment. A transformer has windings formed by one or more coils placed around the transformer core.

[0003] In some cases, circuit breakers are also provided in electrical equipment to protect transformers from the risk of overload or short circuit.

[0004] However, it is known that high-frequency overvoltages can reach the transformer during the operation of opening or closing the circuit breaker. Such overvoltages can cause the transformer to break down.

[0005] In particular, transformer breakdown may occur when the overvoltage amplitude exceeds the voltage amplitude supported by the transformer. In other words, transformer breakdown may occur when the overvoltage exceeds the transformer's basic pulse level (also known as the "BIL level").

[0006] This problem is typically solved by installing a surge arrester connected to the transformer. The surge arrester attenuates or filters voltage amplitudes reaching the transformer, ensuring they remain below the transformer's basis inductance (BIL) level. In some cases, this problem can be solved by installing a grounding rheostat within the transformer. The rheostat is rated for a voltage higher than the voltage supported by the transformer. When the voltage amplitude reaching the transformer exceeds its BIL level, the overvoltage reaching the rheostat is conducted to ground, not the transformer. The transformer is thus protected from overvoltage.

[0007] However, transformer breakdown can also occur when the windings experience resonance. This happens when the voltage flowing through the transformer oscillates at a frequency corresponding to the transformer's resonant frequency.

[0008] Currently, the risk of resonance in the windings is limited by installing RC filters connected to the transformer. RC filters allow the frequency of the voltage flowing in the transformer to be reduced, thus moving it away from the transformer's resonant frequency.

[0009] However, installing an RC filter involves installing additional components in the electrical equipment, which complicates the use and maintenance of the equipment. Summary of the Invention

[0010] This disclosure aims to improve this situation.

[0011] To this end, a method for selecting a transformer model is described, which is executed by a computer system and includes:

[0012] - Model the transformer model, which includes coils configured to support an electric field;

[0013] - Determine a set of frequency intervals that include the resonant frequencies of the transformer model;

[0014] - Calculate the maximum electric field acting on the coil when a voltage oscillating at the stated frequency interval passes through a transformer model;

[0015] - Compare the maximum electric field with the maximum permissible electric field value; and

[0016] - Select the transformer model based on the previous comparisons.

[0017] Therefore, advantageously, the selection of the transformer model is performed by modeling the maximum electric field acting on the coil when a voltage oscillating within the set of resonant frequencies of the transformer model passes through it. The comparison of the maximum electric field with the maximum permissible electric field value allows selection of a transformer model that is unlikely to cause breakdown under the influence of a voltage oscillating within the frequency interval. Thus, the risk of coil breakdown is limited when the voltage flowing in the transformer model oscillates at one of the resonant frequencies of the selected transformer model.

[0018] For example, unlike voltage calculations, electric field calculations allow for the consideration of geometry and dimensions in transformer models, particularly the geometry and dimensions of the coils. This may include irregularities, such as spikes that may accumulate charge, resulting in a significant electric field.

[0019] Therefore, this allows the risk of transformer breakdown to be limited without the need for additional components.

[0020] Furthermore, since this method is executed by a computer system, multiple transformer models can be modeled and tested, while reducing material and economic costs.

[0021] In some cases, the determination of the frequency intervals of the group resonant frequencies of the transformer model is performed based on the determination of the impedance response of the transformer model. In some examples, a graph representing the impedance variation of the transformer model as a function of the frequency of voltage oscillations acting on the transformer model can be obtained. Based on this graph, the frequency intervals of the group resonant frequencies of the transformer model can be determined.

[0022] In some cases, the method for selecting a transformer model also includes determining the voltage distribution in the coil. Determining the voltage distribution allows, for example, the determination of the change in the voltage gradient along the coil. In some cases, the selection of the transformer model takes into account the characteristics of the voltage distribution in the coil. Therefore, the selection of the transformer model can be performed, for example, such that the voltage distribution along the coil is as constant as possible.

[0023] In some cases, transformer modeling involves modeling a coil using multiple slices, each slice comprising multiple turns. For example, modeling allows for the selection of the number of slices and turns of the coil. Depending on the number of slices and the number of turns per slice, the maximum electric field acting on the coil can differ. Similarly, the maximum permissible electric field value can also differ. In other cases, transformer modeling involves modeling a coil with space between each slice. Modeling allows for, for example, the selection of the distance between each slice of the coil. Depending on the distance between the slices, at least one of the maximum electric field acting on the coil and the maximum permissible electric field value can differ. Similarly, the voltage gradient along the coil can also differ. In some cases, transformer modeling involves selecting the material between each turn of the multiple turns of the coil. Therefore, depending on the selected material, the maximum electric field acting on the coil can differ. Similarly, the maximum permissible electric field value can also differ. Furthermore, modeling allows for the calculation of the maximum electric field in the transformer model based on the characteristics of the transformer model and a specific input voltage.

[0024] In some cases, transformer modeling involves selecting the resin used to coat the coils. Therefore, the maximum electric field acting on the coils can differ depending on the resin chosen. Similarly, the maximum permissible electric field value can also vary.

[0025] In some cases, coils are modeled so that at least one structural parameter is selected from the following:

[0026] - The total number of slices;

[0027] - Total number of turns in each slice;

[0028] - The length of the space between each slice of the coil;

[0029] - The distance between the concentric high-voltage coil and the low-voltage coil;

[0030] - The material arranged between each turn in the multiple turns of the coil; and

[0031] - Resin coating the coil.

[0032] Therefore, the characteristics of the modeled coil can vary depending on the selection of structural parameters, allowing for different behaviors of the transformer model. Thus, when a voltage oscillating at the frequency intervals of the group resonant frequencies including the transformer model is applied to the transformer model, a transformer model with satisfactory behavior can be selected.

[0033] In some cases, the method for selecting a transformer model also includes modeling one or more additional transformer models, each including a corresponding coil configured to support a corresponding electric field. The method further includes determining a set of frequency intervals for corresponding resonant frequencies for each additional transformer model. Therefore, multiple transformer models can be tested before selecting a specific transformer model.

[0034] According to another aspect, a method for manufacturing a transformer is described, including the aforementioned method for selecting a transformer model, wherein the manufacturing method comprises manufacturing a transformer according to the selected model. Therefore, this manufacturing method makes it possible to obtain a transformer having characteristics corresponding to the selected transformer model.

[0035] In some cases, transformers are dry-coated transformers. Therefore, resin is coated on the transformer coils, which in particular helps to prevent the transformer coils from coming into contact with fluids flowing near the transformer.

[0036] According to another aspect, a computer program is described, comprising instructions for executing the method for selecting a transformer model as described above when the program is executed by a processor suitable for performing the method for selecting a transformer model. Therefore, the method for selecting a transformer model can be executed by a computer program, which avoids the randomness of manual implementation.

[0037] According to another aspect, a computer system is described, including a processor adapted to perform the method for selecting a transformer model as described above. Therefore, the method for selecting a transformer model can be executed by the computer system. This particularly makes it possible to repeat the method for selecting a transformer model multiple times while limiting costs. Attached Figure Description

[0038] Referring to the accompanying drawings, other features and advantages will become apparent in the following description of some embodiments given by way of non-limiting example. In the figures:

[0039] Figure 1 A first example of a method for selecting a transformer model according to this disclosure is shown.

[0040] Figure 2 A schematic diagram of a longitudinal cross-section of a first example of a transformer coil is shown.

[0041] Figure 3The diagram shows the representation with Figure 2 An example graph of the impedance curve related to the coil.

[0042] Figure 4 A second example of a method for selecting a transformer model according to this disclosure is shown.

[0043] Figure 5 The diagram shows the representation with Figure 2 An example of a voltage distribution curve related to the coil is shown in the figure.

[0044] Figure 6 An example of a method for manufacturing a transformer according to this disclosure is shown.

[0045] Figure 7 An example of a computer system according to this disclosure is shown schematically. Detailed Implementation

[0046] In different figures, the same reference numerals denote the same or similar elements.

[0047] This description relates to methods for selecting transformer models.

[0048] The selection method can be understood as a specific protocol leading to the selection of a transformer model. The purpose of this protocol is, in particular, to select a transformer model based on the estimated performance level for that model in a specific environment. In some cases, the protocol aims to select a transformer model from multiple transformer models. In other cases, the multiple transformer models include at least two transformer models. In this case, the selection of the transformer model is based on the estimated performance level for each transformer model in a specific environment. More precisely, in this case, the purpose of the protocol is to enable the selection of a transformer model that has an improved performance level in a specific environment from multiple transformer models. In some cases, the selection of the transformer model is made from multiple transformer models that have a satisfactory performance level in a specific environment based on parameters such as the cost or availability of the required materials. In this case, the selected transformer model is the one for which the required materials are cheaper or more readily available.

[0049] A specific environment may include a set of parameters external to the transformer model that affect the estimated performance level of the transformer model. Examples of external parameters affecting the transformer performance level are, for example, the electric field, voltage, or intensity acting on the transformer model. Hereinafter, the term "electric field" refers to, for example, the electric field intensity generated by charged particles. For example, the electric field is expressed in volts per meter (V / m).

[0050] Performance level is understood as the behavior of a transformer model in the given specific environment. In some examples, performance level is the transformer model's ability to support electric fields, voltages, or intensities acting on it while avoiding or reducing the likelihood of damage. In some cases, performance level may depend on the value of the electric field acting on the transformer model. In these cases, performance level is considered acceptable when the value of the electric field acting on the transformer model is less than the maximum permissible electric field value.

[0051] The "maximum permissible electric field value" refers to the electric field value acting on the transformer model. Below this value, the possibility of damage to the transformer model is limited. For example, the maximum permissible electric field value is 10 kV / mm. For example, the maximum permissible electric field value is 15 kV / mm. For example, the maximum permissible electric field value is 5 kV / mm.

[0052] The "transformer model" aims to represent a virtual creation of a transformer. A transformer can be understood as an electrical device configured to convert an input signal into an output signal based on the phenomenon of electromagnetic induction. In some cases, the input and output signals are alternating signals. The input signal is characterized, for example, by a first strength and a first voltage. The output signal is characterized, for example, by a second strength and a second voltage. The first strength differs from the second strength, and the first voltage differs from the second voltage. The first strength and the first voltage at least partially define the specific environment of the transformer model.

[0053] A transformer includes at least one coil and a magnetic circuit, also known as a core. In some examples, a transformer includes at least one high-voltage coil and at least one low-voltage coil, which are concentric. The core is made of a ferromagnetic material. In some examples, the core is a soft iron core. The core may include an upper yoke, a lower yoke, and at least one branch. In some cases, the magnetic circuit may include a single yoke and at least one branch. At least one branch and the yoke are each formed from a set of adjacent plates. At least one branch extends substantially perpendicular to the yoke, for example. In some cases, the transformer includes two branches interconnected by the yoke. In some cases, such as when the transformer is a three-phase transformer, the transformer includes three branches interconnected by the yoke. Any other number of branches can be conceived.

[0054] The coils described in this specification form part of a winding. A "winding" refers to a set of turns that form a circuit associated with one of the voltages applied to the transformer. Depending on the voltage assigned to the winding, it is either a high-voltage winding or a low-voltage winding. A high-voltage winding is the winding of a given transformer that specifies the highest voltage. A low-voltage winding is the winding of a given transformer that specifies the lowest voltage.

[0055] The coil described in this specification is, for example, a high-voltage coil. A "high-voltage coil" refers to a coil that forms part of a high-voltage winding. The coil is therefore capable of receiving high-frequency overvoltages because it can be connected to a high-voltage circuit breaker. According to this specification, the coil may comprise a set of slices. The slices are distributed along the longitudinal direction of each coil. In some cases, the coil comprises more than seven slices. In some cases, the coil comprises fewer than twenty slices. In some cases, the coil comprises seven to fifteen slices. Successive slices are separated from each other by spaces. Each space between consecutive slices has a predetermined length. The predetermined length corresponds to the distance between two consecutive slices. In some cases, all spaces between consecutive slices have the same predetermined length.

[0056] In some cases, the spaces between consecutive slices have different lengths. For example, slices are connected in series with each other.

[0057] In some examples, each slice comprises a set of turns. In some examples, each slice comprises dozens of turns. In some cases, the turn set of each slice is formed by windings of metal wire in a plane substantially perpendicular to the longitudinal direction of the coil, which corresponds to the longitudinal direction of the transformer branch. Each slice is contained in a corresponding plane. In some cases, the turn set of each slice is formed by windings of metal wire in multiple stacked planes substantially perpendicular to the longitudinal direction of the coil. The metal wire may be, for example, copper wire. For example, the wire may have a cylindrical or flat shape. In some examples, more than 500 turns are provided in the coil. In some examples, less than 1000 turns are provided in the coil.

[0058] In some examples, insulating material is arranged between each turn. The insulating material is, for example, a polymer material. In some cases, the insulating material is polyethylene terephthalate (PET). The insulating material electrically insulates the turns from each other.

[0059] For example, this description relates to dry-coated transformers. In a dry-coated transformer, each coil is wrapped in resin. In some examples, the resin is a thermosetting resin. In some examples, the resin is an epoxy resin. The resin prevents each coil from coming into contact with fluids flowing near the transformer. For example, the fluid is water vapor, which causes humidity in the environment around the transformer. Similarly, the resin prevents contaminant particles from coming into contact with each coil. The resin also limits the fire risk of the transformer. Dry-coated transformers are also characterized by using only air for cooling. This allows for a simplified structure, reduced size, and limited operating and maintenance costs. In some cases, each coil is coated with an insulating material different from the resin. In some examples, the insulating material is a polymer.

[0060] According to this instruction, the coil is wound, for example, on the branches of the magnetic core. In some cases, a single coil is wound on each branch of the magnetic core. In other cases, multiple coils are wound on some branches or on each branch.

[0061] Transformers come in various types depending on the number of windings in each transformer and the number of coils in each branch of the transformer core. In some cases, a transformer may include two coils, each wound on a separate branch of the core. One coil is called the "primary winding," and the other is called the "secondary winding." The primary winding is configured to receive an input signal, while the secondary winding is configured to generate an output signal. This transformer is a single-phase transformer. In other cases, a transformer may include two coils wound on each branch. Each branch then has both a primary and a secondary winding. When a transformer includes three branches, each with both a primary and a secondary winding wound on it, the transformer is a three-phase transformer. In some cases, a transformer includes a single coil wound on one of the branches of the core. This single coil performs the functions of both the primary and secondary windings. In this case, the transformer is an autotransformer.

[0062] The primary winding is configured to generate magnetic flux upon receiving an input signal. This magnetic flux is transferred to the core. Within the core, the magnetic flux flows until it reaches the secondary winding, which is configured to generate an output signal.

[0063] This description also relates to a computer system configured to perform a method for selecting a transformer model. Therefore, the method for selecting a transformer model according to this description is performed by a computer system. The computer system includes a processor adapted to perform the method for selecting a transformer model. In some examples, the processor includes electronic computing circuitry managed by the computer system and enabling the implementation of a series of algorithms required for the operation of the computer system. In some cases, the computer system is configured to be controlled by a user of the computer system. In some cases, the computer system is configured to operate automatically without the need for user intervention.

[0064] The description also relates to a computer program containing instructions for performing a method for selecting a transformer model when executed by a processor of a computer system.

[0065] This description also relates to a method for manufacturing a transformer. The manufacturing method is understood to include a set of techniques for physically obtaining a transformer. "Physically obtaining" refers to obtaining a transformer in material form. Specifically, the manufacturing method aims to obtain, in material form, a transformer corresponding to a transformer model selected after applying a method for selecting a transformer model. Of course, the multiple transformer models selected in the method for selecting the transformer model can be the subject of the manufacturing method. The method for manufacturing a transformer includes, for example, producing at least one coil and core, and assembling the coil and core.

[0066] Figure 1An example of a method 100 for selecting a transformer model is shown. The selection method 100 includes boxes 101-105, which will be described below.

[0067] The method 100 for selecting a transformer model includes modeling the transformer model in box 101. "Modeling" refers to the production of the transformer model as described above. For this purpose, dedicated modeling or simulation software, executed by an example of the computer system 400, can be used. References will be made below. Figure 7 Describe computer system 400.

[0068] Modeling the transformer model includes modeling coil 10. Figure 2 A schematic diagram of an example of coil 10 is shown. Coil 10 forms part of a transformer model. In some examples, coil 10 is a high-voltage coil. As mentioned above, a high-voltage coil is capable of receiving high-frequency overvoltages because it can be connected to a high-voltage circuit breaker (not shown).

[0069] The modeled coil 10 has a structure similar to the transformer coil structure described above. Specifically, the coil 10 is modeled using multiple slices 12. The multiple slices 12 are distributed along the longitudinal direction A1 of the coil 10. Modeling the coil 10 involves selecting the total number of slices 12 in the coil 10. Figure 2 The example shows seven slices 12, although this number of slices 12 is not limiting. In some cases, coil 10 includes more than seven slices 12. In some cases, coil 10 includes fewer than twenty slices 12. In some cases, coil 10 includes seven to fifteen slices 12.

[0070] Space 14 is positioned between two consecutive slices 12. The length L1 of space 14 corresponds to the distance along the longitudinal direction A1 between the two consecutive slices 12 of coil 10. Modeling of coil 10 includes selecting the length of space 14. In some cases, all spaces 14 between two consecutive slices 12 have the same length L1. In other cases, the length L1 of at least one space 14 is different from the length L1 of the other spaces 14.

[0071] In some cases, coil 10 is also modeled as containing multiple turns (not shown) in each slice 12. In some cases, the multiple turns of each slice 12 are formed by a winding of metal wire around the longitudinal direction A1 of coil 10. In some examples, the winding of the metal wire forming the turns of each slice 12 is made in a plane P1 that is substantially orthogonal to or perpendicular to the longitudinal direction A1 of coil 10. In other words, the metal wire is spirally wound around the longitudinal direction A1 in plane P1, thereby forming multiple loops of metal wire in plane P1. Each loop of metal wire in plane P1 corresponds to one turn. Each slice 12 is associated with a corresponding plane P1.

[0072] Modeling coil 10 involves selecting the total number of turns in each slice 12. In some cases, each slice 12 includes more than 50 turns. In some cases, each slice 12 includes fewer than 100 turns. In some cases, each slice 12 includes 50 to 100 turns. Each slice 12 may contain an equal number of turns. In some cases, at least one slice 12 contains a different number of turns than the other slices 12. In some examples, more than 500 turns are provided in coil 10. In some examples, less than 1000 turns are provided in coil 10.

[0073] Material (not shown) is arranged between each turn. Modeling of coil 10 also includes selecting the material arranged between each turn of coil 10. The material is an insulating material. The material is, for example, a polymer material. In some cases, the material is polyethylene terephthalate (PET).

[0074] In some cases, such as Figure 2 As shown, coil 10 is coated with resin 16. Resin 16 is placed around coil 10. Furthermore, resin 16 completely or partially fills the space 14 between two consecutive slices 12. Modeling of coil 10 also includes the selection of resin 16. In particular, the selection of resin 16 includes at least one of selecting a resin type or a composition of the resin. In some examples, resin 16 is epoxy resin.

[0075] For modeling coil 10, the total number of slices 12, the total number of turns, the length L1 of space 14, and the selection of material or resin 16 between turns can be manually performed by the user of computer system 400. For example, manual selection can be performed using the graphical interface of computer system 400. In some cases, the selection of the total number of slices 12, the total number of turns, the length L1 of space 14, and the material or resin 16 between turns is performed automatically by computer system 400. According to one example, the automatic selection by computer system 400 can be performed randomly. According to one example, the automatic selection can take into account selections made in advance for modeling other transformer models to ensure that the modeled transformer model has at least one different characteristic from the previously modeled transformer model.

[0076] In the transformer model, coil 10 performs the function of the primary winding, as described above. Of course, the transformer model can be modeled with multiple coils, such that the function of the secondary winding, as described above, is performed by a coil different from coil 10. Similarly, as in the transformer example presented above, the transformer model may include at least one low-voltage coil concentric with the high-voltage coil.

[0077] Coil 10 is configured to support a maximum permissible electric field value. The maximum permissible electric field value corresponds to an electric field that can flow within coil 10 without structurally and / or functionally damaging it. In some cases, the maximum permissible electric field value may correspond to an electric field value exceeding which would cause coil 10 to begin to be damaged. In other cases, the maximum permissible electric field value corresponds to any other electric field value that ensures coil 10 is not damaged.

[0078] The maximum permissible electric field value can depend on the length L1 of the space 14 between the two consecutive slices 12, the material arranged between each turn, and the resin 16, which are selected for the coil 10 during the modeling of the transformer model. In some examples, depending on the selected resin 16, the resin 16 will withstand different electric field values ​​without being damaged. Therefore, the maximum permissible electric field value can vary depending on the selected resin 16. In some examples, depending on the selected material between the turns, the material will withstand different electric field values ​​without being damaged. Therefore, the maximum permissible electric field value can vary depending on the selected material between the turns.

[0079] In some cases, in order to perform method 100, the coils of the transformer model are modeled in order to select at least one structural parameter from the following:

[0080] - The total number of slices 12;

[0081] - Total number of turns in each slice of 12;

[0082] -Length L1 of space 14;

[0083] - The distance between the concentric high-voltage coil and the low-voltage coil;

[0084] - The material arranged between each turn in the multiple turns of the coil; and

[0085] -Resin 16.

[0086] Therefore, the maximum permissible electric field value supported by coil 10 can vary depending on the selection of structural parameters. Consequently, the performance curve of the modeled transformer can vary depending on the selection of these structural parameters.

[0087] Block 102 of method 100 includes determining a set of frequency intervals for resonant frequencies of a transformer model. In some cases, "frequency interval" refers to a set of continuous oscillation frequencies of the voltage through the transformer model. In other cases, "frequency interval" refers to a set of discrete oscillation frequencies of the voltage through the transformer model. "Resonant frequency" refers to the oscillation frequency of the voltage through the transformer model at which resonance occurs.

[0088] For example, based on the determination of the impedance response of the transformer model, the determination of a set of frequency intervals including the resonant frequencies of the transformer model is performed.

[0089] The impedance response of the transformer model is determined by computer system 400. Based on the determined impedance response of the transformer model, the impedance curve is obtained.

[0090] An "impedance curve" is a curve representing the change in the modulus and / or independent variable of the impedance of a transformer model as a function of the oscillation frequency of the voltage passing through the transformer model.

[0091] Figure 3 A graph showing an example of impedance curves associated with a transformer model is provided. The horizontal axis corresponds to the oscillation frequency of the voltage through the transformer model. The vertical axis corresponds to the modulus or independent variable of the transformer model's impedance.

[0092] The impedance curve has a first region 30, a second region 40, and a third region 50.

[0093] The first region 30 corresponds to the low-frequency region. In the first region 30, the transformer model exhibits inductive behavior. As the oscillation frequency of the voltage through the transformer model increases, the inductive behavior is characterized by an increase in impedance.

[0094] The third region 50 corresponds to the high-frequency region. In the third region 50, the transformer model exhibits capacitive behavior. As the oscillation frequency of the voltage through the transformer model increases, the capacitive behavior is characterized by a decrease in impedance.

[0095] The second region 40 corresponds to the mid-frequency region between the low-frequency and high-frequency regions. In this second region, the impedance curve is characterized by a set of peaks 42 and a set of valleys 44. The frequency at which each peak 42 and each valley 44 of the impedance curve occurs corresponds to the resonant frequency of the transformer model.

[0096] Therefore, obtaining the impedance curve allows for the determination of a set of resonant frequencies encompassing the transformer model. In some cases, the determined frequency interval includes all resonant frequencies of the transformer model. In other cases, the determined frequency interval includes only some resonant frequencies of the transformer model. In some examples, the first peak 42 of the impedance curve corresponds to the oscillation frequency of the voltage through the transformer model, at which the risk of damage to the transformer model is low. Therefore, the first peak 42 of the impedance curve can be excluded from the determined frequency interval. "First peak" refers to peak 42 that is associated with the lowest frequency among peaks 42. In some cases, the first valley 44 of the impedance curve corresponds to the oscillation frequency of the voltage through each transformer model, at which the risk of damage to the transformer model is particularly high. Therefore, the first valley 44 of the impedance curve can be included in the determined frequency interval. "First valley" refers to valley 44 that is associated with the lowest frequency among valleys 44.

[0097] During modeling according to box 101, the impedance response of the transformer model varies depending on the selection of the number of slices 12, the number of turns, the length L1 of space 14, the distance between the concentric high-voltage coil and low-voltage coil, the material between the turns, and the resin 16 of coil 10.

[0098] Box 102 may also include the selection of frequency increments. The selected frequency increments determine a set of frequencies included in the determined frequency intervals for which the voltage at the nodes of the transformer model is calculated. Therefore, the voltage calculated at the nodes of the transformer model is a voltage oscillating over the determined frequency intervals. "Oscillating voltage" refers to a voltage that varies over time. In some cases, the selected frequency increments are very fine. Therefore, the number of frequencies included in the determined frequency intervals for which the voltage at the transformer nodes is calculated increases.

[0099] Block 103 of method 100 includes calculating the maximum electric field acting on coil 10 when each voltage calculated at a node of the transformer model passes through the transformer model. The calculation of the electric field is performed by computer system 400. Specifically, computer system 400 is configured to simulate the passage of a set of voltages oscillating at frequencies within a defined frequency interval using the transformer model. Thus, a set of electric field values ​​acting on the coil is obtained. Therefore, each obtained electric field value is associated with one of the voltages oscillating at frequencies at the frequency intervals. Based on the obtained set of electric field values, the maximum electric field is determined. Specifically, the maximum electric field corresponds to the obtained maximum electric field value acting on coil 10.

[0100] According to one example, the calculation of the maximum electric field according to block 103 can be performed by computer system 400 based on a simulation of a voltage oscillating only at frequencies corresponding to peaks 42 and valleys 44 included in the defined frequency intervals through a transformer model. Thus, a set of electric field values ​​is obtained that act on coil 10 only when a voltage oscillating at the resonant frequency of the transformer model included in the defined frequency intervals passes through the transformer model.

[0101] In some cases, the smaller the peak 42 and valley 44, the lower the maximum electric field of the transformer model.

[0102] Block 104 of method 100 includes a comparison of the maximum electric field with the maximum permissible electric field value supported by coil 10. Specifically, the comparison between the maximum electric field and the maximum permissible electric field value allows it to be determined whether, for example, the maximum electric field is strictly less than the maximum permissible electric field value. In some cases, computer system 400 is configured to determine whether the maximum electric field is strictly less than the maximum permissible electric field value. In other cases, a user of computer system 400 may determine whether the maximum electric field is strictly less than the maximum permissible electric field value themselves.

[0103] Box 105 of Method 100 includes the selection of a transformer model. The selection in Box 105 is considered in relation to the comparison in Box 104. In some examples, a transformer model will be selected if the maximum electric field is strictly less than the maximum permissible electric field value. Selecting a transformer model whose maximum electric field is strictly less than the maximum permissible electric field value allows for the selection of a transformer model with a limited risk of damage in the presence of overvoltage.

[0104] In some cases, if the maximum electric field is greater than or equal to the maximum permissible electric field value supported by coil 10 during the comparison according to box 104, then the modeled transformer model is not selected. In these cases, method 100 can begin by repeating the modeling of box 101 based on another transformer model that differs from the unselected transformer model in at least one of the aforementioned structural parameters. In particular, method 100 can be repeated continuously until a transformer model is selected.

[0105] In some cases, the modeling included in block 101 of method 100 is not limited to modeling a single transformer model. The modeling included in block 101 may include modeling one or more additional transformer models. In this case, each additional transformer model includes a corresponding coil. Each corresponding coil is structurally and functionally similar to coil 10. Thus, each corresponding coil is defined by multiple slices, multiple turns, the spatial length between two consecutive slices, the material arranged between the turns, and the material coating the coil. Thus, each corresponding coil is configured to support a corresponding maximum permissible electric field value. Method 100 as described above is then applied to each transformer model being modeled. Then, according to block 105, multiple transformer models can be selected during the selection period. In these cases, a final selection can be provided to select a single transformer model from the transformer models selected during the selection period according to block 105. For example, the final selection may be determined by the difference between the maximum permissible electric field values ​​of each selected transformer model. For example, the final selection may be determined by the manufacturing cost of each selected transformer model. For example, the final selection may be determined by the availability of the required materials for each selected transformer model.

[0106] Figure 4 A second example of a method 200 for selecting a transformer model is shown. Selection method 200 includes boxes 101-105 and box 206. Boxes 101-105 are identical to boxes 101-105 in selection method example 100. Therefore, they will not be described in detail further.

[0107] Box 206 includes determining the voltage distribution in coil 10. The determination of the voltage distribution is performed by computer system 400. Specifically, the voltage distribution is determined based on a simulated voltage oscillating at a given frequency using a transformer model. In some examples, the given frequency is included within a frequency interval that includes the set of resonant frequencies of the transformer model. In some cases, the given frequency corresponds to one of the resonant frequencies of the transformer model. The voltage distribution allows the amplification factor of the voltage acting on coil 10 to be determined for each slice 12. The voltage distribution also allows the determination of the variation in the voltage gradient between each slice 12 of coil 10.

[0108] Figure 5 A graph is shown illustrating an example of the voltage distribution associated with coil 10. The horizontal axis corresponds to the ratio of the length of coil 10 through which the voltage acting on coil 10 travels to the total length of coil 10. The vertical axis corresponds to the amplification factor of the voltage acting on coil 10.

[0109] In this case, the voltage distribution indicates that the maximum amplification factor of the voltage acting on coil 10 is obtained at point 60, which is approximately half the total length of coil 10. This means that slice 12 near point 60 has a higher voltage concentration than other slices. In some cases, the higher the maximum voltage amplification factor, the greater the risk of transformer breakdown. Therefore, selection method 200 is, in some cases, aimed at selecting transformer models with low maximum amplification factor values ​​in their voltage distribution. This includes selecting transformer models with substantially flat voltage distribution curves.

[0110] The graph representing the voltage distribution also reflects the variation of the voltage gradient between each slice 12 of coil 10. The voltage gradient allows for analysis of the difference between the voltage values ​​between the two spaces 14. In some cases, the variation in the voltage difference between the two spaces 14 is particularly large at the ends of coil 10, which is indicated by the voltage gradient corresponding to the ends of coil 10. Figure 5 The slope of the voltage distribution in the region of the graph is used to reflect this. In some cases, the steeper the slope of the voltage distribution, the greater the voltage gradient in the coil. The higher the voltage gradient, the greater the risk of transformer breakdown. Therefore, selection method 200 aims to select transformer models with small voltage gradients in some cases. This includes selecting transformer models with a basically flat voltage distribution curve.

[0111] Therefore, in some cases, based on the modeling according to box 101, an attempt is made to obtain a transformer model with the flattest voltage distribution possible. This allows for the avoidance of very high amplification factors. On the other hand, a flat voltage distribution means that the voltage gradient in the coil is small.

[0112] Reducing the number of slices 12, increasing the length L1 of space 14, reducing the number of turns in each slice 12, or increasing the distance between concentric high-voltage and low-voltage coils can lead to a reduction in the voltage gradient in coil 10, thereby resulting in a flatter voltage distribution.

[0113] It should be noted that, in some cases, the highest amplification factor is obtained when the voltage through the transformer model oscillates at a frequency corresponding to the first valley 44 of the corresponding impedance curve of the transformer model.

[0114] exist Figure 4 In the example, determining the voltage distribution according to box 206 occurs after determining the frequency interval according to box 102. In some cases, determining the voltage distribution according to box 206 can occur at any time between determining the frequency interval according to box 102 and selecting the transformer model according to box 105.

[0115] This description also relates to an example of method 300 for manufacturing a transformer. Figure 6 An example of a method 300 for manufacturing a transformer is shown. Method 300 includes blocks 100 and 307. Block 100 corresponds to the selection method example 100 described above. Therefore, it will not be described in detail below. In some cases, method 300 for manufacturing a transformer may include blocks 200 and 307, with block 200 corresponding to the selection method example 200 described above. In particular, the manufacturing method aims to obtain, in material form, a transformer corresponding to the transformer model selected after applying method 100 for selecting a transformer model. When multiple transformer models are selected after applying selection method 100, manufacturing method 300 may aim to obtain each selected transformer model.

[0116] Box 307 includes manufacturing a transformer according to the model selected based on method 100. This manufacturing allows a transformer corresponding to the selected transformer model to be physically obtained. In some examples, the manufactured transformer is a dry-coated transformer.

[0117] Figure 7 An example of a computer system 400 including a processor 401 is shown. The processor 401 is configured, for example, to execute method 100 or 200 for selecting a transformer model according to the example above. The processor 401 may include electronic computing circuitry managed by an operating system.

[0118] The computer system 400 also includes a non-volatile storage medium 402, which is machine-readable or readable by the computer system 400. The storage medium 402 is, for example, a memory or storage cell. According to this disclosure, the storage medium 402 can be any type of electronic, magnetic, or optical storage device, or another physical device storing executable instructions. Memory can be, for example, random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), a memory card reader, an optical disc, etc.

[0119] Storage medium 402 may, for example, store a computer program according to this disclosure. The computer program includes instructions 403 for performing the methods 100, 200 for selecting a transformer model as described above. The computer program is executed by processor 401.

[0120] As described above, the computer system 400 may also include a graphical interface (not shown) that allows the user to manually select the structural parameters of the modeled coil 10.

Claims

1. A method (100, 200) for selecting a transformer model during transformer manufacturing, the method being performed by a computer system (400), the method comprising: - Model the transformer model, which includes coils (10) configured to support an electric field; - Determine a set of frequency intervals that include the resonant frequencies of the transformer model; - Calculate the maximum electric field acting on the coil (10) when the voltage oscillating at the said frequency interval passes through the transformer model; - Compare the maximum electric field with the maximum allowable electric field value; as well as - The transformer model is selected based on the comparison between the maximum electric field and the maximum allowable electric field value, and this transformer model is used to manufacture the transformer.

2. The method (100, 200) according to claim 1, wherein, The determination of the frequency intervals of the set of resonant frequencies of the transformer model is performed based on the determination of the impedance response of the transformer model.

3. The method (200) according to claim 1 or 2 further includes determining the voltage distribution in the coil (10).

4. The method (200) according to claim 3, wherein, The selection of the transformer model takes into account the characteristics of the voltage distribution in the coil (10).

5. The method (100, 200) according to claim 1, wherein, Modeling the transformer model involves modeling the coil (10) with multiple slices (12), each slice (12) of the coil (10) comprising multiple turns.

6. The method (100, 200) according to claim 5, wherein, Modeling the transformer model involves modeling the coil (10) with spaces (14) between each slice (12) of the coil (10).

7. The method (100, 200) according to claim 5, wherein, Modeling the transformer model involves selecting the material between each turn of the multiple turns of the coil (10).

8. The method (100, 200) according to claim 1, wherein, Modeling the transformer model includes selecting the resin (16) for coating the coil (10).

9. The method (100, 200) according to claim 5, wherein, The coil (10) is modeled to select at least one structural parameter from the following: - The total number of slices (12); - Total number of turns in each slice (12); - The length (L1) of the space (14) between each slice (12) of the coil; - The distance between the concentric high-voltage coil and the low-voltage coil; - The material arranged between each turn in the multiple turns of the coil (10); and - Resin (16) coating the coil (10).

10. The method of claim 1 (100, 200) further includes modeling one or more additional transformer models, each additional transformer model including a corresponding coil configured to support a corresponding electric field, the method further including determining a set of corresponding resonant frequencies for each additional transformer model.

11. A method (300) for manufacturing a transformer, comprising a method (100, 200) for selecting a transformer model during the manufacturing of the transformer according to any one of the preceding claims, the manufacturing method (300) comprising manufacturing the transformer according to the selected model.

12. The method (300) for manufacturing a transformer according to claim 11, wherein the transformer is a dry-coated transformer.

13. A computer program product comprising instructions for performing the method (100, 200) for selecting a transformer model during the manufacture of a transformer, as described in any one of claims 1 to 10, when the program is executed by a processor adapted to perform the method (100, 200) for selecting a transformer model during the manufacture of a transformer, as described in any one of claims 1 to 10.

14. A computer system (400) comprising a processor (401) adapted to perform a method (100, 200) for selecting a transformer model during the manufacture of a transformer according to any one of claims 1 to 10.

Images