Method and device for constructing equivalent circuit model of three-phase five-column transformer

Abstract

The invention discloses a three-phase five-column transformer equivalent circuit model construction method and device, and the method comprises the steps: building a geometric model of a three-phase five-column transformer in finite element simulation software, carrying out the zero-sequence short-circuit test and the positive-sequence short-circuit test of the geometric model of the three-phase five-column transformer, obtaining the zero-sequence short-circuit impedance and the positive-sequence short-circuit impedance between windings, and obtaining the equivalent circuit model of the three-phase five-column transformer. A coupling leakage inductance matrix representing the coupling relation of the windings of the three-phase five-column transformer is calculated, and an equivalent circuit model of the three-phase five-column transformer is constructed in electromagnetic transient simulation software based on the coupling leakage inductance matrix of the three-phase five-column transformer. The technical problems of high resource consumption and long simulation time existing in modeling of the equivalent circuit model of the three-phase five-column transformer in an existing finite element modeling mode and the problem that the coupling relation among three-phase windings cannot be accurately represented in modeling of the equivalent circuit model of the three-phase five-column transformer in an equivalent circuit modeling mode are solved. And the accurate simulation requirement of a multi-winding structure cannot be met.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and particularly to a method and device for constructing an equivalent circuit model of a three-phase five-column transformer. Background Art

[0002] The three-phase five-column transformer is a core device for large-capacity power transmission. At present, the methods for constructing the equivalent model of the three-phase five-column transformer include the finite element modeling method and the equivalent circuit modeling method. The finite element modeling is widely used in electromagnetic transient simulation. However, due to the complexity of the transformer structure, the finite element modeling faces the problems of high resource consumption and long simulation time. When dealing with the disk-type winding structure, the equivalent circuit modeling method fails to accurately characterize the coupling relationship between the three-phase windings and cannot meet the accurate simulation requirements for multi-winding structures. Therefore, how to solve the problems of high resource consumption and long simulation time in the equivalent circuit model modeling of the three-phase five-column transformer by the finite element modeling method and the problem that the equivalent circuit modeling method fails to accurately characterize the coupling relationship between the three-phase windings and cannot meet the accurate simulation requirements for multi-winding structures in the equivalent circuit model modeling of the three-phase five-column transformer is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0003] The present invention provides a method and device for constructing an equivalent circuit model of a three-phase five-column transformer, which are used to solve the technical problems of high resource consumption and long simulation time in the equivalent circuit model modeling of the three-phase five-column transformer by the existing finite element modeling method and the technical problems that the equivalent circuit modeling method fails to accurately characterize the coupling relationship between the three-phase windings and cannot meet the accurate simulation requirements for multi-winding structures in the equivalent circuit model modeling of the three-phase five-column transformer.

[0004] In view of this, the first aspect of the present invention provides a method for constructing an equivalent circuit model of a three-phase five-column transformer, including:

[0005] Establishing a geometric model of the three-phase five-column transformer in a finite element simulation software based on the physical dimensions of the three-phase five-column transformer;

[0006] Respectively conducting zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-column transformer, and respectively obtaining the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer;

[0007] Calculating the coupling leakage inductance matrix of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer;

[0008] Constructing an equivalent circuit model of the three-phase five-column transformer in an electromagnetic transient simulation software based on the coupling leakage inductance matrix of the three-phase five-column transformer.

[0009] Optionally, conduct zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-column transformer respectively, and obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between each winding of the three-phase five-column transformer, including:

[0010] Conduct a zero-sequence short-circuit test on each pair of windings of the geometric model of the three-phase five-column transformer, apply a zero-sequence excitation to the primary side of the geometric model of the three-phase five-column transformer, and short-circuit the secondary side at the same time to calculate the zero-sequence short-circuit impedance;

[0011] Conduct a positive-sequence short-circuit test on each pair of windings of the geometric model of the three-phase five-column transformer, apply a positive-sequence excitation to the geometric model of the three-phase five-column transformer, and short-circuit the secondary side at the same time to calculate the positive-sequence short-circuit impedance.

[0012] Optionally, calculate the coupled leakage inductance matrix of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between each winding of the three-phase five-column transformer, including:

[0013] Calculate the self-impedance and mutual impedance between each winding of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between each winding of the three-phase five-column transformer;

[0014] Calculate the coupled leakage inductance matrix of the three-phase five-column transformer according to the self-impedance and mutual impedance between each winding of the three-phase five-column transformer.

[0015] Optionally, the calculation formula for the self-impedance between each winding of the three-phase five-column transformer is:

[0016]

[0017] where, is the self-impedance between two windings, is the zero-sequence short-circuit impedance between two windings, is the positive-sequence short-circuit impedance between two windings;

[0018] The calculation formula for the mutual impedance between each winding of the three-phase five-column transformer is:

[0019]

[0020] where, is the self-impedance between two windings.

[0021] Optionally, the coupled leakage inductance matrix of the three-phase five-column transformer is:

[0022]

[0023]

[0024]

[0025] where, is the coupling leakage inductance matrix of a three-phase five-column transformer, is the self-impedance matrix between the windings of a three-phase five-column transformer, is the mutual impedance matrix between the windings of a three-phase five-column transformer, is an element in the self-impedance matrix between the windings of a three-phase five-column transformer, is an element in the mutual impedance matrix between the windings of a three-phase five-column transformer.

[0026] Optionally, after constructing an equivalent circuit model of a three-phase five-column transformer in an electromagnetic transient simulation software based on the coupling leakage inductance matrix of the three-phase five-column transformer, it further includes:

[0027] Introducing a switching device to simulate a short-circuit fault based on the equivalent circuit model of the three-phase five-column transformer, and obtaining the short-circuit fault simulation result of the equivalent circuit model of the three-phase five-column transformer.

[0028] The second aspect of the present invention provides a device for constructing an equivalent circuit model of a three-phase five-column transformer, including:

[0029] A finite element module for establishing a geometric model of a three-phase five-column transformer in a finite element simulation software based on the physical dimensions of the three-phase five-column transformer;

[0030] A short-circuit test module for respectively performing zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-column transformer to obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer respectively;

[0031] A coupling leakage inductance matrix calculation module for calculating the coupling leakage inductance matrix of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer;

[0032] An equivalent circuit model construction module for constructing an equivalent circuit model of a three-phase five-column transformer in an electromagnetic transient simulation software based on the coupling leakage inductance matrix of the three-phase five-column transformer.

[0033] Optionally, the short-circuit test module is specifically used for:

[0034] Performing a zero-sequence short-circuit test on each pair of windings of the geometric model of the three-phase five-column transformer, applying a zero-sequence excitation to the primary side of the geometric model of the three-phase five-column transformer, and short-circuiting the secondary side at the same time to calculate the zero-sequence short-circuit impedance;

[0035] Performing a positive-sequence short-circuit test on each pair of windings of the geometric model of the three-phase five-column transformer, applying a positive-sequence excitation to the geometric model of the three-phase five-column transformer, and short-circuiting the secondary side at the same time to calculate the positive-sequence short-circuit impedance.

[0036] Optionally, the coupling leakage inductance matrix calculation module is specifically used for:

[0037] Based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of a three-phase five-leg transformer, calculate the self-impedance and mutual impedance between the windings of the three-phase five-leg transformer;

[0038] According to the self-impedance and mutual impedance between the windings of the three-phase five-leg transformer, calculate the coupled leakage inductance matrix of the three-phase five-leg transformer.

[0039] Optionally, it further includes:

[0040] A short-circuit fault simulation module, which is used to introduce switching devices to simulate short-circuit faults based on the equivalent circuit model of the three-phase five-leg transformer, and obtain the short-circuit fault simulation results of the equivalent circuit model of the three-phase five-leg transformer.

[0041] As can be seen from the above technical solutions, the method for constructing an equivalent circuit model of a three-phase five-leg transformer provided by the present invention has the following advantages:

[0042] The method for constructing an equivalent circuit model of a three-phase five-leg transformer provided by the present invention establishes a geometric model of the three-phase five-leg transformer in a finite element simulation software, conducts zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-leg transformer to obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings, and then calculates the coupled leakage inductance matrix representing the winding coupling relationship of the three-phase five-leg transformer. Based on the coupled leakage inductance matrix of the three-phase five-leg transformer, an equivalent circuit model of the three-phase five-leg transformer is constructed in an electromagnetic transient simulation software, breaking through the technical bottleneck that the existing equivalent circuit model of the three-phase five-leg transformer winding has difficulty in characterizing the coupling relationship between windings when dealing with disk windings, and also avoiding the disadvantage of long time in simulation based on the finite element model. It solves the technical problems of high resource consumption and long simulation time in modeling the equivalent circuit model of the three-phase five-leg transformer by the existing finite element modeling method and the technical problems that the equivalent circuit modeling method for modeling the equivalent circuit model of the three-phase five-leg transformer fails to accurately characterize the coupling relationship between the three windings and cannot meet the precise simulation requirements for multi-winding structures. Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0044] Figure 1 It is a schematic flow chart of a method for constructing an equivalent circuit model of a three-phase five-leg transformer provided in an embodiment of the present invention;

[0045] Figure 2This is the schematic diagram of the zero-sequence short-circuit test for the three-phase five-leg transformer provided in the embodiment of the present invention;

[0046] Figure 3 This is the schematic diagram of the positive-sequence short-circuit test for the three-phase five-leg transformer provided in the embodiment of the present invention;

[0047] Figure 4 This is the equivalent circuit model of the three-phase five-leg transformer provided in the embodiment of the present invention;

[0048] Figure 5 This is the short-circuit simulation example diagram of the equivalent circuit model of the three-phase five-leg transformer provided in the embodiment of the present invention;

[0049] Figure 6 This is the structural schematic diagram of a device for constructing an equivalent circuit model of a three-phase five-leg transformer provided in the embodiment of the present invention. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0051] For ease of understanding, please refer to Figure 1 , the present invention provides an embodiment of a method for constructing an equivalent circuit model of a three-phase five-leg transformer, including:

[0052] Step 101: Establish a geometric model of the three-phase five-leg transformer in a finite element simulation software based on the physical dimensions of the three-phase five-leg transformer.

[0053] It should be noted that in the embodiment of the present invention, a geometric model of the three-phase five-leg transformer is established in a finite element simulation software based on the physical dimensions of the three-phase five-leg transformer. The geometric model of the three-phase five-leg transformer mainly includes three parts: the iron core, the winding, and the oil domain. Among them, the iron core structure is constructed in the form of stacking silicon steel sheets; according to the pre-analyzed geometric model scale, the winding of the three-phase five-leg transformer is virtually divided into multiple sub-windings to construct a multi-winding model; the oil domain is simplified into a cuboid structure.

[0054] Step 102: Conduct zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-leg transformer respectively, and obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-leg transformer respectively.

[0055] It should be noted that based on the geometric model of the three-phase five-column transformer constructed in step 101, zero-sequence short-circuit tests and positive-sequence short-circuit tests are carried out on any two ports to obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer. Specifically, first, a zero-sequence short-circuit test is performed on each pair of windings, and the principle of the zero-sequence short-circuit test is as Figure 2 shown. In the zero-sequence short-circuit test, a zero-sequence excitation is applied to the primary side of the geometric model of the three-phase five-column transformer, and at the same time, the secondary side is short-circuited, so as to calculate the zero-sequence short-circuit impedance. Then, a positive-sequence short-circuit test is performed on each pair of windings of the geometric model of the three-phase five-column transformer, and the principle of the positive-sequence short-circuit test is as Figure 3 shown. In the positive-sequence short-circuit test, a positive-sequence excitation is applied to the geometric model of the three-phase five-column transformer, and at the same time, the secondary side is short-circuited, so as to calculate the positive-sequence short-circuit impedance.

[0056] Step 103: Calculate the coupled leakage inductance matrix of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer.

[0057] It should be noted that based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer calculated in step 102, the self-impedance and mutual impedance between the windings of the three-phase five-column transformer are further calculated to characterize its sequence component characteristics. Specifically, the calculation formula for the self-impedance between the windings of the three-phase five-column transformer is:

[0058]

[0059] where is the self-impedance between two windings, is the zero-sequence short-circuit impedance between two windings, is the positive-sequence short-circuit impedance between two windings;

[0060] The calculation formula for the mutual impedance between the windings of the three-phase five-column transformer is:

[0061]

[0062] where is the self-impedance between two windings.

[0063] According to the self-impedance and mutual impedance between the windings of the three-phase five-column transformer, a self-impedance matrix and a mutual impedance matrix are constructed. Specifically, the self-impedance matrix between the windings of the three-phase five-column transformer is:

[0064]

[0065] where is the self-impedance matrix between the windings of the three-phase five-column transformer, is an element in the self-impedance matrix between the windings of a three-phase five-leg transformer, which can be calculated according to the above-mentioned calculation formula for the self-impedance between the windings of a three-phase five-leg transformer.

[0066] The mutual-impedance matrix between the windings of a three-phase five-leg transformer is:

[0067]

[0068] Among them, is the mutual-impedance matrix between the windings of a three-phase five-leg transformer, is an element in the mutual-impedance matrix between the windings of a three-phase five-leg transformer, which can be calculated according to the above-mentioned calculation formula for the mutual-impedance between the windings of a three-phase five-leg transformer.

[0069] The coupled leakage inductance matrix of a three-phase five-leg transformer is:

[0070]

[0071] Among them, is the coupled leakage inductance matrix of a three-phase five-leg transformer.

[0072] Step 104: Based on the coupled leakage inductance matrix of the three-phase five-leg transformer, construct an equivalent circuit model of the three-phase five-leg transformer in the electromagnetic transient simulation software.

[0073] It should be noted that based on the coupled leakage inductance matrix of the three-phase five-leg transformer calculated in step 103, an inductance matrix module representing the winding coupling relationship is constructed. In the electromagnetic transient simulation software, an equivalent circuit model of the three-phase five-leg transformer suitable for internal short-circuit analysis is constructed, as Figure 4 shown. This equivalent circuit model consists of an ideal transformer, a resistor element, and an inductance matrix module representing the winding coupling relationship. In this equivalent circuit model, each sub-winding is composed of an ideal transformer in series with a resistor element. Through the primary side port of the ideal transformer, the voltage and current data of each port can be directly measured. The secondary side of the ideal transformer is connected according to the Figure 4 shown connection method to realize the normalization processing of the electrical parameters of each port. In this article, Figure 4 the left ideal transformer in is defined as the main circuit winding, and the right ideal transformer is the branch winding. First, complete the wiring of the secondary side of the ideal transformer. As Figure 4 shown, the secondary side of each phase main circuit winding is connected to the left end of the inductance matrix module through multiple wires, and the other ends of the three-phase main circuit windings are grounded together. The right end of the inductance matrix module is directly connected to the corresponding ports of each phase branch winding, and the other ends of the three-phase branch windings are also grounded together, thus completing the connection of the secondary side of the ideal transformer. Next, connect the ports of the primary side of the ideal transformer. The primary side ports of each ideal transformer are wired according to the actual electrical connection method of the sub-windings.

[0074] The method for constructing an equivalent circuit model of a three-phase five-column transformer provided by the present invention includes establishing a geometric model of the three-phase five-column transformer in a finite element simulation software, conducting zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-column transformer to obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between each winding, and then calculating the coupling leakage inductance matrix representing the coupling relationship of the windings of the three-phase five-column transformer. Based on the coupling leakage inductance matrix of the three-phase five-column transformer, an equivalent circuit model of the three-phase five-column transformer is constructed in an electromagnetic transient simulation software, breaking through the technical bottleneck that the existing equivalent circuit model of the three-phase five-column transformer windings has difficulty in characterizing the coupling relationship between windings when dealing with disk windings, and also avoiding the disadvantage of long simulation time in simulation based on a finite element model. It solves the technical problems of high resource consumption and long simulation time in modeling the equivalent circuit model of the three-phase five-column transformer by the existing finite element modeling method, and the technical problem that the equivalent circuit modeling method for the equivalent circuit model of the three-phase five-column transformer fails to accurately characterize the coupling relationship between the three-phase windings and cannot meet the precise simulation requirements for multi-winding structures.

[0075] In one embodiment, after step 104, it further includes:

[0076] Step 105: Introduce a switching device to simulate a short-circuit fault based on the equivalent circuit model of the three-phase five-column transformer, and obtain the short-circuit fault simulation result of the equivalent circuit model of the three-phase five-column transformer.

[0077] It should be noted that the short-circuit fault of the three-phase five-column transformer is a common and most serious accident type. The large current caused by the short circuit may lead to the explosion of the transformer, resulting in huge economic losses and even endangering the safety of personnel. Using a finite element model to simulate the short-circuit fault of the three-phase five-column transformer model consumes a lot of resources and has a long simulation time. In the embodiment of the present invention, for the equivalent circuit model of the three-phase five-column transformer constructed by steps 101 to 104, a switching device is connected in series at both ends of the short-circuited winding, the closing time is set to the short-circuit moment, and the occurrence of the short circuit is simulated by closing the switch. Taking Figure 5 the equivalent circuit model of the three-phase five-column transformer shown as an example for illustration, this model divides each phase into four windings. Among them, the left main circuit winding is the low-voltage port, and the right branch windings are connected in series to form the high-voltage port. The high-voltage side is connected in star, and the low-voltage side is connected in delta. After connecting a time-controlled switch at both ends of the short-circuited winding and setting the closing time, the short-circuit fault of the transformer can be simulated. Through the electromagnetic transient simulation software, the voltage and current data of each port during the short-circuit process can be obtained, providing a theoretical basis and a mechanism model for short-circuit fault analysis. It should be pointed out that Figure 5Only a simulation example of a specific short - circuit condition is shown. The actual equivalent circuit model can simulate all internal short - circuit conditions. All short - circuit fault simulations of the three - phase five - limb transformer equivalent circuit models constructed based on the model construction method proposed in this invention are included within the protection scope of this invention.

[0078] For ease of understanding, please refer to Figure 6 , an embodiment of a device for constructing a three - phase five - limb transformer equivalent circuit model is provided in this invention, including:

[0079] A finite - element module, used to establish a geometric model of the three - phase five - limb transformer in finite - element simulation software based on the physical dimensions of the three - phase five - limb transformer;

[0080] A short - circuit test module, used to conduct zero - sequence short - circuit tests and positive - sequence short - circuit tests on the geometric model of the three - phase five - limb transformer respectively, and obtain the zero - sequence short - circuit impedance and positive - sequence short - circuit impedance between each winding of the three - phase five - limb transformer;

[0081] A coupled leakage inductance matrix calculation module, used to calculate the coupled leakage inductance matrix of the three - phase five - limb transformer based on the zero - sequence short - circuit impedance and positive - sequence short - circuit impedance between each winding of the three - phase five - limb transformer;

[0082] An equivalent circuit model construction module, used to construct an equivalent circuit model of the three - phase five - limb transformer in electromagnetic transient simulation software based on the coupled leakage inductance matrix of the three - phase five - limb transformer.

[0083] In one embodiment, the short - circuit test module is specifically used for:

[0084] Conduct a zero - sequence short - circuit test on each pair of windings of the geometric model of the three - phase five - limb transformer, apply a zero - sequence excitation to the primary side of the geometric model of the three - phase five - limb transformer, and short - circuit the secondary side at the same time to calculate the zero - sequence short - circuit impedance;

[0085] Conduct a positive - sequence short - circuit test on each pair of windings of the geometric model of the three - phase five - limb transformer, apply a positive - sequence excitation to the geometric model of the three - phase five - limb transformer, and short - circuit the secondary side at the same time to calculate the positive - sequence short - circuit impedance.

[0086] In one embodiment, the coupled leakage inductance matrix calculation module is specifically used for:

[0087] Calculate the self - impedance and mutual - impedance between each winding of the three - phase five - limb transformer based on the zero - sequence short - circuit impedance and positive - sequence short - circuit impedance between each winding of the three - phase five - limb transformer;

[0088] Calculate the coupled leakage inductance matrix of the three - phase five - limb transformer according to the self - impedance and mutual - impedance between each winding of the three - phase five - limb transformer.

[0089] In one embodiment, the device for constructing a three - phase five - limb transformer equivalent circuit model further includes:

[0090] The short-circuit fault simulation module is used to introduce a switching device to simulate a short-circuit fault based on the three-phase five-leg transformer equivalent circuit model, and obtain the short-circuit fault simulation result of the three-phase five-leg transformer equivalent circuit model.

[0091] In one embodiment, the calculation formula for the self-impedance between the windings of the five-phase transformer is:

[0092]

[0093] in, is the self-impedance between the two windings, is the zero-sequence short-circuit impedance between the two windings, is the positive sequence short-circuit impedance between the two windings;

[0094] The calculation formula for the mutual impedance between the windings of a three-phase five-leg transformer is:

[0095]

[0096] in, is the self-impedance between the two windings.

[0097] The coupled leakage inductance matrix of the five-phase transformer is:

[0098]

[0099]

[0100]

[0101] in, is the coupled leakage inductance matrix of the three-phase five-leg transformer, is the self-impedance matrix between the windings of the three-phase five-leg transformer, is the mutual impedance matrix between the windings of the three-phase five-leg transformer, is the element in the self-impedance matrix between the windings of the three-phase five-leg transformer, It is an element in the mutual impedance matrix between the windings of a three-phase five-leg transformer.

[0102] The three-phase five-column transformer equivalent circuit model construction device provided in the present invention is used to execute the three-phase five-column transformer equivalent circuit model construction method provided in the present invention. Its principle and technical effects are the same as those of the three-phase five-column transformer equivalent circuit model construction method provided in the present invention, and will not be repeated here.

[0103] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing an equivalent circuit model of a three-phase five-column transformer, characterized in that, Including: Establish a geometric model of the three-phase five-column transformer in the finite element simulation software based on the physical dimensions of the three-phase five-column transformer; Conduct zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-column transformer respectively, and obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer respectively; Calculate the coupled leakage inductance matrix of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer; Construct an equivalent circuit model of the three-phase five-column transformer in the electromagnetic transient simulation software based on the coupled leakage inductance matrix of the three-phase five-column transformer.

2. The method for constructing an equivalent circuit model of a three-phase five-column transformer according to claim 1, wherein Conduct zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-column transformer respectively, and obtain the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer respectively, including: Conduct a zero-sequence short-circuit test on each pair of windings of the geometric model of the three-phase five-column transformer, apply a zero-sequence excitation to the primary side of the geometric model of the three-phase five-column transformer, and short-circuit the secondary side at the same time to calculate the zero-sequence short-circuit impedance; Conduct a positive-sequence short-circuit test on each pair of windings of the geometric model of the three-phase five-column transformer, apply a positive-sequence excitation to the geometric model of the three-phase five-column transformer, and short-circuit the secondary side at the same time to calculate the positive-sequence short-circuit impedance.

3. The method for constructing an equivalent circuit model of a three-phase five-column transformer according to claim 2, wherein Calculate the coupled leakage inductance matrix of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer, including: Calculate the self-impedance and mutual impedance between the windings of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer; Calculate the coupled leakage inductance matrix of the three-phase five-column transformer according to the self-impedance and mutual impedance between the windings of the three-phase five-column transformer.

4. The method for constructing an equivalent circuit model of a three-phase five-column transformer according to claim 3, characterized in that The calculation formula for the self-impedance between the windings of the three-phase five-column transformer is: Among them, is the self-impedance between the two windings, is the zero-sequence short-circuit impedance between the two windings, is the positive-sequence short-circuit impedance between the two windings; The calculation formula for the mutual impedance between the windings of the three-phase five-column transformer is: Among them, is the self-impedance between the two windings.

5. The method for constructing an equivalent circuit model of a three-phase five-column transformer according to claim 4, characterized in that The coupled leakage inductance matrix of the three-phase five-column transformer is: Among them, is the coupling leakage inductance matrix of the three-phase five-column transformer, is the self-impedance matrix between the windings of the three-phase five-column transformer, is the mutual impedance matrix between the windings of the three-phase five-column transformer, is the element in the self-impedance matrix between the windings of the three-phase five-column transformer, is the element in the mutual impedance matrix between the windings of the three-phase five-column transformer.

6. The method for constructing an equivalent circuit model of a three-phase five-column transformer according to claim 1, wherein After constructing the equivalent circuit model of the three-phase five-column transformer in the electromagnetic transient simulation software based on the coupled leakage inductance matrix of the three-phase five-column transformer, it further includes: Introduce switching devices to simulate short-circuit faults based on the equivalent circuit model of the three-phase five-column transformer, and obtain the short-circuit fault simulation results of the equivalent circuit model of the three-phase five-column transformer.

7. A device for constructing an equivalent circuit model of a three-phase five-column transformer, characterized in that, Including: A finite element module for establishing a geometric model of the three-phase five-column transformer in the finite element simulation software based on the physical dimensions of the three-phase five-column transformer; A short-circuit test module for conducting zero-sequence short-circuit tests and positive-sequence short-circuit tests on the geometric model of the three-phase five-column transformer respectively, and obtaining the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer respectively; A coupled leakage inductance matrix calculation module for calculating the coupled leakage inductance matrix of the three-phase five-column transformer based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer; An equivalent circuit model construction module for constructing an equivalent circuit model of the three-phase five-column transformer in the electromagnetic transient simulation software based on the coupled leakage inductance matrix of the three-phase five-column transformer.

8. The device for constructing the equivalent circuit model of a three-phase five-column transformer according to claim 7, characterized in that, The short-circuit test module is specifically used for: Conduct a zero-sequence short-circuit test on each pair of windings of the geometric model of the three-phase five-column transformer, apply a zero-sequence excitation to the primary side of the geometric model of the three-phase five-column transformer, and short-circuit the secondary side at the same time to calculate the zero-sequence short-circuit impedance; For each pair of windings in the geometric model of the three-phase five-column transformer, a positive-sequence short-circuit test is carried out. A positive-sequence excitation is applied to the geometric model of the three-phase five-column transformer, and at the same time, the secondary side is short-circuited to calculate the positive-sequence short-circuit impedance.

9. The device for constructing the equivalent circuit model of a three-phase five-column transformer according to claim 8, characterized in that, The coupled leakage inductance matrix calculation module is specifically used for: Based on the zero-sequence short-circuit impedance and positive-sequence short-circuit impedance between the windings of the three-phase five-column transformer, calculate the self-impedance and mutual impedance between the windings of the three-phase five-column transformer; According to the self-impedance and mutual impedance between the windings of the three-phase five-column transformer, calculate the coupled leakage inductance matrix of the three-phase five-column transformer.

10. The device for constructing the equivalent circuit model of a three-phase five-column transformer according to claim 7, wherein, It also includes: A short-circuit fault simulation module, which is used to simulate a short-circuit fault by introducing a switching device based on the equivalent circuit model of the three-phase five-column transformer to obtain the short-circuit fault simulation result of the equivalent circuit model of the three-phase five-column transformer.

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