Transformer harmonic transfer characteristic analysis method and equipment based on phase sequence component decomposition

Abstract

The invention relates to a power equipment technology, in particular to a transformer harmonic transfer characteristic analysis method and device based on phase sequence component decomposition, and the method comprises the steps: proposing a three-sequence equivalent model of a YNd11 three-phase double-winding transformer based on a classic T-type equivalent circuit of the transformer; according to an impedance star-delta transformation formula, equivalently obtaining a three-sequence equivalent model of the YNd11 three-phase double-winding transformer subjected to star-delta transformation by using the proposed three-sequence equivalent model, and then displacing the parallel branch to obtain a three-sequence equivalent model of the YNd11 transformer subjected to parallel branch equivalence; according to the equivalent YNd11 transformer three-sequence equivalent model after parallel branch displacement, a harmonic transfer relation under a sequence component is deduced; and deriving the harmonic transfer relationship under the phase component based on the harmonic transfer relationship under the sequence component. The method provides a theoretical basis for researching on-line harmonic monitoring, harmonic state estimation, harmonic responsibility division and harmonic pollution control of a power system.

Description

Technical Field

[0001] The present invention belongs to the technical field of power equipment, and in particular relates to a method and device for analyzing transformer harmonic transfer characteristics based on phase sequence component decomposition. Background Art

[0002] With the increasing penetration of power electronic equipment in power grids, power systems are gradually becoming more electronic. This has led to the emergence of a vast variety of harmonic pollution sources across the source-grid-load interface. These sources not only inject a large number of harmonics into the system but also cause widespread harmonic propagation through the interconnected structure of the power grid, significantly degrading power quality. Furthermore, the complexity of power system topologies and the variability of their parameters result in significant nonlinearities in harmonic propagation. Harmonic transmission paths and attenuation characteristics vary significantly across different network structures, increasing the difficulty of harmonic control. Further complicating matters, harmonic components of specific frequencies can trigger series or parallel resonance in the system. This resonance can lead to abnormal amplification of harmonic voltages or currents, causing varying degrees of damage to power equipment, including accelerated insulation aging and overheating. Given this, in-depth research into the transmission mechanisms of harmonics in power grids and a systematic analysis of their propagation patterns are of great theoretical and practical significance for preventing harmonic amplification, improving power quality, and ensuring the safe and stable operation of power systems.

[0003] Existing research typically categorizes harmonic transfer into two main categories: transmission of the same voltage level through transmission lines and transmission of different voltage levels through transformers. This paper focuses on the latter. Currently, research on the harmonic transfer characteristics of transformers, both domestically and internationally, primarily analyzes the amplification of primary and secondary voltage and current amplitudes by defining the transformer's harmonic voltage and current transfer coefficients. However, the impact of three-phase imbalance on transformer harmonic transfer is not considered. Summary of the Invention

[0004] The present invention provides a method and device for analyzing the harmonic transfer characteristics of a transformer based on phase sequence component decomposition, which is used to overcome the defect in the prior art that the impact of three-phase imbalance on the harmonic transfer of the transformer is not considered, and to better clarify the transmission rules of harmonics of different orders when passing through the transformer from the perspective of harmonics of different properties.

[0005] The present invention provides a method for analyzing transformer harmonic transfer characteristics based on phase sequence component decomposition, comprising the following steps: Step 1: Based on the classic T-type equivalent circuit of the transformer, a three-sequence equivalent model of the YNd11 three-phase double-winding transformer is proposed; Step 2: According to the impedance star-delta transformation formula, the three-sequence equivalent model is used to obtain the three-sequence equivalent model of the YNd11 three-phase double-winding transformer after the star-delta transformation, and then the parallel branch is displaced to obtain the three-sequence equivalent model of the YNd11 transformer after the parallel branch is equivalent; Step 3: Based on the three-sequence equivalent model of the YNd11 transformer after the parallel branch is equivalent, the harmonic transfer relationship under the sequence component is derived; Step 4: Based on the harmonic transfer relationship under the sequence component, the harmonic transfer relationship under the phase component is derived.

[0006] According to a transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition provided by the present invention, the three-sequence equivalent model of the YNd11 three-phase double-winding transformer includes: a positive-sequence equivalent model, a negative-sequence equivalent model and a zero-sequence equivalent model.

[0007] According to a transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition provided by the present invention, the positive sequence equivalent model includes the primary side voltage U a1 , the voltage on the secondary side U b1 , primary side current I a1 , the current on the secondary side I b1 ; Primary winding equivalent admittance y a , secondary winding equivalent admittance y b ; Positive sequence excitation admittance y c1 , non-standard transformation ratio on the primary side α , non-standard transformation ratio on the secondary side β ; Primary winding equivalent admittance y a Non-standard transformation ratio of left end and primary side α The ideal transformer winding is connected, and the right side is connected by the secondary winding equivalent admittance y b Non-standard transformation ratio on the secondary side β The ideal transformer winding is connected, and on the other hand, the positive sequence excitation admittance y c1 connected to the earth; The negative sequence equivalent model includes the primary side voltage U a2 , the voltage on the secondary side U b2 , primary side current I a2 , the current on the secondary side I b2 ; Primary winding equivalent admittance ya , secondary winding equivalent admittance y b , non-standard transformation ratio on primary side α , non-standard transformation ratio on the secondary side β ; Primary winding equivalent admittance y a Non-standard transformation ratio between left end and primary side α The ideal transformer winding is connected, and the right end is connected through the secondary winding equal admittance y b Non-standard transformation ratio on the secondary side β The ideal transformer winding is connected, and on the other hand, the negative sequence excitation admittance y c1 connected to the earth; The zero-sequence equivalent model includes the primary side voltage U a0 , the voltage on the secondary side U b0 , primary side current I a0 , the current on the secondary side I b0 ; Primary winding equivalent admittance y a , secondary winding equivalent admittance y b , zero-sequence excitation admittance y c0 , non-standard transformation ratio on primary side α , non-standard transformation ratio on the secondary side β ; Primary winding equivalent admittance y a Non-standard transformation ratio between left end and primary side α The ideal transformer winding is connected, and the right side has the same admittance as the secondary winding. y b and zero-sequence excitation admittance y c0 The parallel branches are connected to each other and connected to the ground.

[0008] According to a transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition provided by the present invention, the admittance parameter portion of the transformer with a Y-type connection between the primary and secondary sides is subjected to the following star-delta transformation:

[0009] Where, y 1 is the winding positive sequence series admittance, y 2 is the winding negative sequence series admittance, y a1 is the positive sequence shunt admittance of the primary side of the winding, y a2is the primary side negative sequence shunt admittance of the winding, y b1 is the positive sequence shunt admittance of the secondary side of the winding, y b2 is the negative sequence shunt admittance of the winding secondary side; For the convenience of calculation, the parallel admittance branch is equivalent to the outside of the transformer, where y a0 is the zero-sequence parallel admittance after series-parallel equivalent: .

[0010] According to a transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition provided by the present invention, the transformer harmonic transfer relationship under the sequence component is as follows: .

[0011] According to a transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition provided by the present invention, based on the transformer harmonic transfer relationship under the sequence component, the YNd11 transformer sequence component series admittance matrix is ​​obtained as follows:

[0012] Similarly, the sequence component parallel admittance matrix is:

[0013] and

[0014] Write the sequence component series admittance matrix in block matrix form:

[0015] Among them, the block matrix modules of the sequence component series admittance matrix are as follows:

[0016]

[0017]

[0018] .

[0019] According to a transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition provided by the present invention, the harmonic transfer relationship under the phase component is: Based on the sequence component admittance matrix of the three-phase transformer, the phase component admittance matrix of the YNd11 transformer is obtained by matrix multiplication, that is, the harmonic transfer relationship under the phase component. The matrix T and the inverse matrix of matrix T are multiplied on the left and right sides of the sequence component admittance matrix, and the results are as follows: (1) Phase component series self-admittance matrix:

[0020]

[0021] (2) Mutual admittance matrix of the primary and secondary sides of the phase component:

[0022]

[0023] (3) Phase component parallel admittance matrix:

[0024] The zero-sequence current on the secondary side of the YNd11 transformer cannot pass through. .

[0025] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition.

[0026] The present invention also provides a computer-readable storage medium having a computer program / instruction stored thereon. When the computer program / instruction is executed by a processor, the steps of the transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition are implemented.

[0027] The present invention also provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the steps of the transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition.

[0028] Compared with the prior art, the present invention has the following beneficial effects: Based on the classic T-type equivalent circuit of the transformer, the present invention takes the YNd11 three-phase double-winding transformer as an example, proposes a transformer three-sequence equivalent model, and derives the transformer harmonic transfer relationship under the sequence component and phase component based on the decomposition of the phase sequence component. Compared with the existing method that only analyzes the transfer characteristics of harmonics through the transformer through the harmonic voltage and harmonic current transfer coefficients, a harmonic transfer matrix under the phase sequence component is proposed. It can more finely clarify the transfer rules of harmonics of different orders when passing through the transformer from the three perspectives of harmonics of different properties, namely positive sequence, negative sequence and zero sequence, provide a reference for studying the propagation of harmonics in the power grid, help to carry out subsequent harmonic control, and improve the power quality of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a flow chart of a method for analyzing transformer harmonic transfer characteristics based on phase sequence component decomposition provided by an embodiment of the present invention; FIG2 (a) is a positive sequence equivalent model of a YNd11 transformer provided by an embodiment of the present invention; FIG2( b ) is a negative sequence equivalent model of a YNd11 transformer provided by an embodiment of the present invention; FIG2 (c) is a zero-sequence equivalent model of a YNd11 transformer provided by an embodiment of the present invention; FIG3 (a) is a positive sequence equivalent model of a YNd11 transformer after star-delta transformation provided by an embodiment of the present invention; FIG3 (b) is a negative sequence equivalent model of a YNd11 transformer after star-delta transformation provided by an embodiment of the present invention; FIG3 (c) is a zero-sequence equivalent model of the YNd11 transformer after star-delta transformation provided by an embodiment of the present invention; FIG4 (a) is a positive sequence equivalent model of a YNd11 transformer after the parallel branches are equivalent provided by an embodiment of the present invention; FIG4 (b) is a negative sequence equivalent model of the YNd11 transformer after the parallel branch is equivalent provided by an embodiment of the present invention; FIG4 (c) is a zero-sequence equivalent model of the YNd11 transformer after the parallel branch is equivalent provided by an embodiment of the present invention; Figure 5 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] This embodiment discloses a method for analyzing the harmonic transfer characteristics of a transformer based on phase-sequence component decomposition. An equivalent circuit model of a three-phase transformer under different sequence components is established and a mathematical model is derived. Then, based on the harmonic transfer mathematical model under the sequence component, the harmonic transfer relationship under the phase component is calculated. This method provides a theoretical basis for studying online harmonic monitoring, harmonic state estimation, harmonic responsibility division, and harmonic pollution control in power systems.

[0033] This embodiment is achieved through the following technical solutions: Figure 1 As shown, the method and device for analyzing the harmonic transfer characteristics of a transformer based on phase sequence component decomposition include the following steps: S1: Based on the classic T-type equivalent circuit of the transformer, a three-sequence equivalent model of the YNd11 three-phase double-winding transformer is proposed; S2: According to the impedance star-delta transformation formula, the three-sequence equivalent model proposed in S1 is used to obtain the three-sequence equivalent model of the YNd11 three-phase double-winding transformer after star-delta transformation. Then, the parallel branches are displaced to obtain the three-sequence equivalent model of the YNd11 transformer after the parallel branches are equivalent. S3: Based on the equivalent YNd11 transformer three-sequence equivalent model after the parallel branch is displaced in S2, the harmonic transfer relationship under the sequence component is derived; S4: Based on the harmonic transfer relationship of the sequence component in S3, the harmonic transfer relationship of the phase component is derived; In S1, for the YNd11 transformer positive sequence equivalent model shown in Figure 2 (a), the equivalent model includes the voltages on the primary and secondary sides. U a1 and U b1 , the current on the primary and secondary sides I a1 and I b1 , the primary winding equivalent admittance and the secondary winding equivalent admittance y a and y b , positive sequence excitation admittance y c1 , non-standard transformation ratio on primary side α , non-standard transformation ratio on the secondary side β , where the primary winding equivalent admittance is y a Non-standard transformation ratio of left end and primary side α The ideal transformer winding is connected, and the right side is connected by the secondary winding equivalent admittance y b Non-standard transformation ratio on the secondary side β The ideal transformer winding is connected, and on the other hand, the positive sequence excitation admittance yc1 Connected to the earth; for the negative sequence equivalent model of the YNd11 transformer shown in Figure 2 (b), the equivalent model includes the voltages on the primary and secondary sides U a2 and U b2 , the current on the primary and secondary sides I a2 and I b2 , the primary winding equivalent admittance and the secondary winding equivalent admittance y a and y b , negative sequence excitation admittance y c2 , non-standard transformation ratio on primary side α , non-standard transformation ratio on the secondary side β , where the primary winding equivalent admittance is y a Non-standard transformation ratio of left end and primary side α The ideal transformer winding is connected, and the right side is connected by the secondary winding equivalent admittance y b Non-standard transformation ratio on the secondary side β The ideal transformer winding is connected, and on the other hand, the negative sequence excitation admittance y c1 Connected to the earth; for the YNd11 transformer zero-sequence equivalent model shown in Figure 2 (c), the equivalent model includes the voltages on the primary and secondary sides U a0 and U b0 , the current on the primary and secondary sides I a0 and I b0 , the primary winding equivalent admittance and the secondary winding equivalent admittance y a and y b , zero-sequence excitation admittance y c0 , non-standard transformation ratio on primary side α , non-standard transformation ratio on the secondary side β , where the primary winding equivalent admittance is y a Non-standard transformation ratio of left end and primary side α The ideal transformer winding is connected, and the right side has the same admittance as the secondary winding. y b It is connected to the branch in parallel with the zero-sequence excitation admittance and connected to the ground.

[0034] In S2, the transformer admittance parameter part of the Y-type connection between the primary and secondary sides in Figures 2 (a) and 2 (b) in S1, that is, in Figure 2 (a) y a 、 y b 、 y c1 And Figure 2(b) y a 、 y b 、 y c2 The Y-type connection position is transformed into the following star-delta:

[0035] For the positive sequence equivalent model of the YNd11 transformer after star-delta transformation shown in Figure 3 (a), the equivalent model includes the voltages on the primary and secondary sides. U a1 and U b1 , the current on the primary and secondary sides I a1 and I b1 , winding positive sequence series admittance y 1. Positive sequence parallel admittance of the primary side of the winding y a1 , positive sequence parallel admittance of the secondary side of the winding y b1 , non-standard transformation ratio on primary side α , non-standard transformation ratio on the secondary side β , where the winding positive sequence series admittance is y 1. Non-standard ratio between the left and primary sides α The ideal transformer winding is connected to the other side of the winding positive sequence parallel admittance y a1 Connected to the ground, the right side has a non-standard transformation ratio with the secondary side β The ideal transformer winding is connected to the other side, and the positive sequence parallel admittance of the winding secondary side is connected to the other side. y b1 Connected to the ground; for the negative sequence equivalent model of the YNd11 transformer after star-delta transformation shown in Figure 3 (b), the equivalent model includes the voltages on the primary and secondary sides U a2 and U b2 , the current on the primary and secondary sides I a2 and I b2 , winding negative sequence series admittance y 2. Negative sequence parallel admittance of the primary side of the windingy a2 , winding secondary side negative sequence shunt admittance y b2 , non-standard transformation ratio on the primary side α , non-standard transformation ratio on the secondary side β , where the winding negative sequence series admittance y 2. Non-standard ratio on the left side and the primary side α The ideal transformer winding is connected to the other side of the winding positive sequence parallel admittance y a2 Connected to the ground, the right side has a non-standard transformation ratio with the secondary side β The ideal transformer winding is connected to the other side, and the positive sequence parallel admittance of the winding secondary side is connected to the other side. y b2 Connected to the ground; for the convenience of calculation, the parallel admittance branches in Figures 3 (a), 3 (b) and 3 (c) are equivalent to the outside of the transformer to obtain Figures 4 (a), 4 (b) and 4 (c), where y a0 is the zero-sequence parallel admittance after series-parallel equivalence.

[0036]

[0037] In S3, according to the three-sequence equivalent model of the YNd11 transformer after the parallel branch in S2 is equivalent, corresponding to Figures 4(a), 4(b), and 4(c), respectively, based on circuit knowledge, the transformer harmonic transfer relationship under the sequence components represented by the primary and secondary side voltage and current and admittance parameters is derived as follows:

[0038] From the above harmonic transfer relationship, the relationship matrix between the positive-sequence, negative-sequence and zero-sequence currents and the corresponding positive-sequence, negative-sequence and zero-sequence voltages can be obtained, that is, the YNd11 transformer sequence component series admittance matrix is:

[0039] Similarly, the sequence component parallel admittance matrix is:

[0040] and

[0041] Write the sequence component series admittance matrix in block matrix form:

[0042] Among them, the block matrix modules of the sequence component series admittance matrix are as follows:

[0043]

[0044]

[0045]

[0046] In S4, based on the sequence component admittance matrix of the YNd11 three-phase transformer in S3, the phase component admittance matrix of the YNd11 transformer can be obtained by matrix multiplication, that is, the harmonic transfer relationship under the phase component. The left and right sides of the sequence component admittance matrix are multiplied by the matrix T and the inverse matrix of the matrix T. The result is as follows.

[0047] (1) Phase component series self-admittance matrix:

[0048]

[0049] (2) Mutual admittance matrix of the primary and secondary sides of the phase component:

[0050]

[0051] (3) Phase component parallel admittance matrix:

[0052] Because the zero-sequence current on the secondary side of the YNd11 transformer cannot pass, then:

[0053] From the mathematical derivation of the embodiment, it can be seen that the transformer harmonic transfer characteristic analysis method and device based on phase sequence component decomposition proposed in the present invention start from the three-order properties of harmonics of different orders, take into account the situation where the phase angle of harmonics of different phase sequences is offset when passing through the transformer, and quantify the characteristics of the changes in amplitude and phase angle of harmonics of different properties when passing through the transformer by establishing a transformer harmonic transfer matrix. This can comprehensively study the transmission law of harmonics when passing through the transformer, breaking the traditional limitation of relying solely on the harmonic transfer coefficient to analyze the harmonic transfer relationship of the transformer.

[0054] Figure 5 An example of a physical structure diagram of an electronic device is shown below. Figure 5As shown, the electronic device may include: a processor, a communications interface, a memory, and a communications bus, wherein the processor, the communications interface, and the memory communicate with each other via the communications bus. The processor may invoke logic instructions in the memory to execute a transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition.

[0055] Furthermore, the logical instructions in the aforementioned memory can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0056] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition provided by the above methods.

[0057] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition provided by the above methods.

[0058] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0059] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0060] Finally, it should be noted that 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition is characterized by: The following steps are involved: Step 1: Based on the classic T-type equivalent circuit of the transformer, a three-sequence equivalent model of the YNd11 three-phase double-winding transformer is proposed; Step 2: According to the impedance star-delta transformation formula, the three-sequence equivalent model is used to obtain the three-sequence equivalent model of the YNd11 three-phase double-winding transformer after the star-delta transformation, and then the parallel branch is displaced to obtain the three-sequence equivalent model of the YNd11 transformer after the parallel branch is equivalent; Step 3: Based on the three-sequence equivalent model of the YNd11 transformer after the parallel branch is equivalent, the harmonic transfer relationship under the sequence component is derived; Step 4: Based on the harmonic transfer relationship under the sequence component, the harmonic transfer relationship under the phase component is derived.

2. The transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition according to claim 1 is characterized in that: The three-sequence equivalent model of the YNd11 three-phase double-winding transformer includes: positive-sequence equivalent model, negative-sequence equivalent model and zero-sequence equivalent model.

3. The transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition according to claim 2 is characterized in that: The positive sequence equivalent model includes the primary side voltage U a1 , the voltage on the secondary side U b1 , primary side current I a1 , the current on the secondary side I b1 ; Primary winding equivalent admittance y a , secondary winding equivalent admittance y b ; Positive sequence excitation admittance y c1 , non-standard transformation ratio on the primary side α , non-standard transformation ratio on the secondary side β ; Primary winding equivalent admittance y a Non-standard transformation ratio of left end and primary side α The ideal transformer winding is connected, and the right side is connected by the secondary winding equivalent admittance y b Non-standard transformation ratio on the secondary side β The ideal transformer winding is connected, and on the other hand, the positive sequence excitation admittance y c1 connected to the earth; The negative sequence equivalent model includes the primary side voltage U a2 , the voltage on the secondary side U b2 , primary side current I a2 , the current on the secondary side I b2 ; Primary winding equivalent admittance y a , secondary winding equivalent admittance y b , non-standard transformation ratio on the primary side α , non-standard transformation ratio on the secondary side β ; Primary winding equivalent admittance y a Non-standard transformation ratio between left end and primary side α The ideal transformer winding is connected, and the right end is connected through the secondary winding equal admittance y b Non-standard transformation ratio on the secondary side β The ideal transformer winding is connected, and on the other hand, the negative sequence excitation admittance y c1 connected to the earth; The zero-sequence equivalent model includes the primary side voltage U a0 , the voltage on the secondary side U b0 , primary side current I a0 , the current on the secondary side I b0 ; Primary winding equivalent admittance y a , secondary winding equivalent admittance y b , zero-sequence excitation admittance y c0 , non-standard transformation ratio on the primary side α , non-standard transformation ratio on the secondary side β ; Primary winding equivalent admittance y a Non-standard transformation ratio between left end and primary side α The ideal transformer winding is connected, and the right side has the same admittance as the secondary winding. y b and zero-sequence excitation admittance y c0 The parallel branches are connected to each other and connected to the ground.

4. The transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition according to claim 3 is characterized in that: For the admittance parameter part of the transformer with Y-type connection between the primary and secondary sides, the following star-delta transformation is performed: Where, y 1 is the winding positive sequence series admittance, y 2 is the winding negative sequence series admittance, y a1 is the positive sequence shunt admittance of the primary side of the winding, y a2 is the primary side negative sequence shunt admittance of the winding, y b1 is the positive sequence shunt admittance of the secondary side of the winding, y b2 is the negative sequence shunt admittance of the winding secondary side; For the convenience of calculation, the parallel admittance branch is equivalent to the outside of the transformer, where y a0 is the zero-sequence parallel admittance after series-parallel equivalent: 。 5. The transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition according to claim 4 is characterized in that: The transformer harmonic transfer relationship under the sequence component is as follows: 。 6. The transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition according to claim 5 is characterized in that: Based on the transformer harmonic transfer relationship under the sequence component, the YNd11 transformer sequence component series admittance matrix is ​​obtained as follows: Similarly, the sequence component parallel admittance matrix is: and Write the sequence component series admittance matrix in block matrix form: Among them, the block matrix modules of the sequence component series admittance matrix are as follows: 。 7. The transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition according to claim 6, characterized in that: The harmonic transfer relationship under the phase component is: Based on the sequence component admittance matrix of the three-phase transformer, the phase component admittance matrix of the YNd11 transformer is obtained by matrix multiplication, that is, the harmonic transfer relationship under the phase component. The matrix T and the inverse matrix of matrix T are multiplied on the left and right sides of the sequence component admittance matrix, and the results are as follows: (1) Phase component series self-admittance matrix: (2) Mutual admittance matrix of the primary and secondary sides of the phase component: (3) Phase component parallel admittance matrix: The zero-sequence current on the secondary side of the YNd11 transformer cannot pass through. 。 8. An electronic device comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the transformer harmonic transfer characteristics analysis method based on phase sequence component decomposition according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the steps of the transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition as claimed in any one of claims 1 to 7 are implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the transformer harmonic transfer characteristic analysis method based on phase sequence component decomposition according to any one of claims 1 to 7 are implemented.

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