Impedance modeling method and system for new energy station, medium and product

Abstract

The invention discloses an impedance modeling method and system for a new energy station, a medium and a product. The method comprises the following steps: carrying out multi-level modular segmentation on the new energy station; wherein the frequency coupling characteristic is reserved in the modular segmentation of each level; and constructing a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level so as to form a frequency coupling characteristic impedance matrix of the whole new energy field station. According to the method, multi-level modular segmentation is carried out on the new energy station, the frequency coupling phenomenon is fully considered during modeling, and the impedance matrix and the admittance matrix are combined during combination of different modules, so that the accuracy of each link is ensured, and the accuracy of the impedance model of the whole station is further ensured.

Description

Technical Field

[0001] The present application relates to the technical field of new energy stations, and in particular to an impedance modeling method, system, medium and product for new energy stations. Background Art

[0002] As environmental issues become increasingly prominent, new energy power stations that use renewable energy such as solar energy and wind energy to generate electricity have developed rapidly and become an important supporting power source for my country's power system. However, in the practice of grid-connected large-scale photovoltaic power stations, many harmonic resonance accidents have occurred. This resonance phenomenon involves the interaction of various voltage source inverters, transmission networks and other power electronic devices, showing the characteristics of strong harmonic coupling and wide-band resonance. In severe cases, it even causes broadband oscillation problems, threatening the safe and reliable operation of the power system.

[0003] At present, commonly used resonance analysis methods include eigenvalue analysis, impedance analysis and frequency sweeping. Due to its advantages such as simple operation and clear physical meaning, the frequency sweeping method has been widely used in engineering. Using a single unit or several units to replace large-scale renewable energy power stations is a major idea in the current electromagnetic transient simulation analysis of renewable energy power systems. The impedance model of a large renewable energy power station established using the equivalent method often ignores the differences in operating conditions and operating parameters of different units. There is a certain gap between the equivalent model and the precise model. When the system is in critical stability, this gap may lead to misjudgment of the final stability determination.

[0004] Therefore, a more accurate broadband impedance model at the renewable energy site level is crucial for the stability analysis of renewable energy grid connection. Summary of the invention

[0005] In view of this, the purpose of this application is to provide an impedance modeling method, system, medium and product for a new energy station to ensure the accuracy of the impedance model of the entire station and facilitate the stability analysis of the new energy grid connection.

[0006] The technical solutions adopted by this application to solve the above technical problems are as follows:

[0007] In a first aspect, the present application provides an impedance modeling method for a new energy station, the method comprising:

[0008] The new energy station is modularly segmented at multiple levels, wherein each level of modular segmentation retains frequency coupling characteristics;

[0009] A frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix is ​​constructed from a low level to a high level to form a frequency coupling characteristic impedance matrix of the entire new energy site.

[0010] In one example, the multi-level modular segmentation of the new energy station includes:

[0011] The new energy station is divided into a unit layer, a regional layer and a station layer from low to high.

[0012] In one example, the impedance types of the entire new energy site include grid-connected inverters, transformers, and cable lines.

[0013] In one example, in the process of constructing a frequency-coupling characteristic admittance matrix or a frequency-coupling characteristic impedance matrix, it is also necessary to construct a corresponding frequency-coupling characteristic admittance matrix or a frequency-coupling characteristic impedance matrix for devices with non-frequency-coupling characteristics.

[0014] In one example, constructing a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level includes:

[0015] First, the frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix corresponding to the lowest level is constructed, and then the corresponding frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix is ​​constructed to the upper level until the frequency coupling characteristic impedance matrix of the entire new energy station is obtained.

[0016] In one example, a corresponding frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix is ​​constructed according to the connection mode between the modules.

[0017] In one example, constructing a corresponding frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix according to the connection mode between the modules includes:

[0018] For low-level modules connected in series, the impedance matrices of each low-level module are superimposed to form the impedance matrix of the high-level module;

[0019] For low-level modules connected in parallel, the impedance matrices of each low-level module are first inverted and transformed into an admittance matrix, and then the admittance matrices of each low-level module are superimposed to form the admittance matrix of the high-level module. Finally, the admittance matrix of the high-level module is inverted to obtain the impedance matrix of the high-level module.

[0020] A second aspect of the present application provides an impedance modeling system for a new energy station, the system comprising:

[0021] A segmentation module, used for performing multi-level modular segmentation on the new energy station; wherein each level of modular segmentation retains frequency coupling characteristics;

[0022] The building module is used to build a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level to form a frequency coupling characteristic impedance matrix of the entire new energy site.

[0023] A third aspect of the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed, the impedance modeling method of the new energy station as described in any one of the above items is implemented.

[0024] The fourth aspect of the present application provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the impedance modeling method of the new energy station as described in any one of the above items.

[0025] The impedance modeling method, system, medium and product of the new energy station provided in the embodiments of the present application, by performing multi-level modular segmentation of the new energy station, fully consider the frequency coupling phenomenon when modeling, and also use the combination in the form of impedance matrix and admittance matrix when combining different modules, thereby ensuring the accuracy of each link and further ensuring the accuracy of the impedance model of the entire station. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of an impedance modeling method for a new energy station provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of the unit layer of a new energy station provided in an embodiment of the present application;

[0028] Figure 3 A schematic diagram of the regional layer of a new energy station provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of the station layer of a new energy station provided in an embodiment of the present application;

[0030] Figure 5 Schematic diagram of the impedance modeling system of the new energy station provided in an embodiment of the present application.

[0031] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] Variables and their definitions involved in the embodiments of this application:

[0034] C dc:Converter DC side capacitor

[0035] Z l :Converter filter inductor

[0036] C l :Converter filter capacitor

[0037] T: Transformer

[0038] Z RA , Z RB , Z RN : Unit connection impedance matrix in the area

[0039] Z S1 , Z S2 , Z SN : Regional connection impedance matrix within the station

[0040] Z vsc :Converter module impedance matrix considering frequency coupling characteristics

[0041] Z T :Transformer module impedance matrix considering frequency coupling characteristics

[0042] Z g :Impedance matrix of new energy unit module considering frequency coupling characteristics

[0043] Z RAA :Impedance matrix of module A with line impedance of new energy unit considering frequency coupling characteristics

[0044] Z RBB :Impedance matrix of the B module with line impedance of the new energy unit considering the frequency coupling characteristics

[0045] Z RNN :Impedance matrix of N modules of new energy units with line impedance considering frequency coupling characteristics

[0046] Y RAA :Impedance matrix of module A with line impedance of new energy unit considering frequency coupling characteristics

[0047] Y RBB :Impedance matrix of the B module with line impedance of the new energy unit considering the frequency coupling characteristics

[0048] Y RNN :Impedance matrix of N modules of new energy units with line impedance considering frequency coupling characteristics

[0049] Y R1 : The admittance matrix of the region 1 module considering the frequency coupling characteristics

[0050] Y R2: The admittance matrix of the region 2 module considering the frequency coupling characteristics

[0051] Y Rn : The admittance matrix of the region n module considering the frequency coupling characteristics

[0052] Z R1 : Impedance matrix of region 1 module considering frequency coupling characteristics

[0053] Z R2 : Impedance matrix of region 2 module considering frequency coupling characteristics

[0054] Z Rn : Impedance matrix of region n modules considering frequency coupling characteristics

[0055] Z1: Impedance matrix of region 1 module and region line impedance considering frequency coupling characteristics

[0056] Z2: Impedance matrix of region 2 modules and region line impedance considering frequency coupling characteristics

[0057] Z n : Impedance matrix of regional n modules and regional line impedance considering frequency coupling characteristics

[0058] Y1: Impedance admittance of region 1 module and region line impedance considering frequency coupling characteristics

[0059] Y2: Impedance admittance of region 2 module and region line impedance considering frequency coupling characteristics

[0060] Y n : Impedance admittance of regional n modules and regional line impedance considering frequency coupling characteristics

[0061] Y ST :Admittance matrix of new energy station considering frequency coupling characteristics

[0062] Z ST :Impedance matrix of new energy station considering frequency coupling characteristics

[0063] Z op :Positive sequence impedance of new energy stations

[0064] like Figure 1 As shown, an embodiment of the present application provides an impedance modeling method for a new energy station, and the impedance modeling method includes the steps of:

[0065] S11, performing multi-level modular segmentation on the new energy station; wherein each level of modular segmentation retains frequency coupling characteristics;

[0066] S12. Construct a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level to form a frequency coupling characteristic impedance matrix of the entire new energy site.

[0067] In one example, the multi-level modular segmentation of the new energy station includes:

[0068] The new energy station is divided into a unit layer, a regional layer and a station layer from low to high.

[0069] Among them, the impedance types of the entire new energy station include grid-connected inverters, transformers and cable lines.

[0070] like Figure 4 As shown in the figure, the station layer of the new energy station includes area 1 to area n, and the regional connection lines in the station (Z in the figure) S1 ~Z SN As shown in the figure). Regional layer, for example, region 1 includes unit A, unit B, ..., unit N, and the unit connection lines in the region (Z in the figure) RA ~Z RN As shown). At the unit level, for example, unit A includes a grid-connected inverter VSC, a transformer T, and a filter inductor Z connected between the grid-connected inverter VSC and the transformer T. l And filter capacitor C l , connected to the bus capacitor C on the DC side of the grid-connected inverter VSC dc .

[0071] In one example, in the process of constructing a frequency-coupling characteristic admittance matrix or a frequency-coupling characteristic impedance matrix, it is also necessary to construct a corresponding frequency-coupling characteristic admittance matrix or a frequency-coupling characteristic impedance matrix for devices with non-frequency-coupling characteristics.

[0072] In one example, constructing a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level includes:

[0073] First, the frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix corresponding to the lowest level is constructed, and then the corresponding frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix is ​​constructed to the upper level until the frequency coupling characteristic impedance matrix of the entire new energy station is obtained.

[0074] In one example, a corresponding frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix is ​​constructed according to the connection mode between the modules.

[0075] Specifically, for low-level modules connected in series, the impedance matrices of each low-level module are superimposed to form the impedance matrix of the high-level module; for low-level modules connected in parallel, the impedance matrices of each low-level module are first inverted and transformed into an admittance matrix, and then the admittance matrices of each low-level module are superimposed to form the admittance matrix of the high-level module, and finally the admittance matrix of the high-level module is inverted to obtain the impedance matrix of the high-level module.

[0076] The following combination Figure 2-Figure 4 The process of forming the frequency coupling characteristic impedance matrix of the entire new energy station is explained:

[0077] like Figure 2-Figure 4 As shown in FIG. 1 , according to the type of grid-connected inverter VSC and the frequency coupling characteristics of the new energy unit, the frequency coupling characteristic impedance matrix Z of the grid-connected inverter VSC considering frequency coupling is constructed. vsc According to the equivalent circuit model of the transformer, the frequency coupling characteristic impedance matrix Z of the transformer is constructed. T .

[0078] According to the new energy impedance matrix Z vsc And the transformer impedance matrix Z T , and get the impedance matrix Z of the new energy unit g , as shown in Equation 1:

[0079] Z g =Z VSC +Z T .

[0080] Considering the series relationship between the unit and the impedance of the connecting line of the units in the area, the following equation 2 is obtained:

[0081] Z RAA =Z g +Z RA

[0082] Z RBB =Z g +Z RB

[0083]

[0084] Z RNN =Z g +Z RN .

[0085] Considering that the units in the region are in parallel, it is necessary to find the admittance matrix of each unit connected in series with the connecting line, as shown in Equation 3 below:

[0086]

[0087] Therefore, the admittance matrix of the entire area is as shown in Equation 4:

[0088] Y R1 =Y RAA +Y RBB +…+Y RNN .

[0089] That is, the regional module impedance is shown in equation 5:

[0090]

[0091] Considering the series relationship between the regional module and the regional connection line impedance, the impedance matrix of the regional module and the regional connection line impedance in series can be obtained, as shown in the following equation 6:

[0092] Z1=Z R1 +Z s1

[0093] Z2=Z R2 +Z s2

[0094]

[0095] Z n =Z Rn +Z sn .

[0096] Considering that the modules in each area of ​​the new energy station are in parallel, it is necessary to find the admittance matrix of each area connected in series with the connecting line impedance, as shown in the following equation 7:

[0097]

[0098] Therefore, the admittance matrix of the entire new energy station is as shown in equation 8:

[0099] Y ST =Y1+Y2+…+Y n .

[0100] That is, the impedance matrix of the new energy station is shown in equation 9:

[0101]

[0102] The impedance matrix of the new energy station can be written as shown in the following formula 10:

[0103]

[0104] Then the positive sequence impedance of the new energy station is as follows:

[0105]

[0106] like Figure 5 As shown, another embodiment of the present application provides an impedance modeling system for a new energy station, the system comprising:

[0107] A segmentation module 21 is used to perform multi-level modular segmentation on the new energy station; wherein each level of modular segmentation retains frequency coupling characteristics;

[0108] The construction module 22 is used to construct a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level to form a frequency coupling characteristic impedance matrix of the entire new energy site.

[0109] In one example, the segmentation module 21 segments the new energy station into a unit layer, a regional layer and a station layer from low to high.

[0110] Among them, the impedance types of the entire new energy station include grid-connected inverters, transformers and cable lines.

[0111] In one example, during the process of constructing the frequency coupling characteristic admittance matrix or the frequency coupling characteristic impedance matrix, the construction module 22 needs to construct the corresponding frequency coupling characteristic admittance matrix or the frequency coupling characteristic impedance matrix for the device with non-frequency coupling characteristics.

[0112] In one example, the construction module 22 first constructs the frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix corresponding to the lowest level, and then constructs the corresponding frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix to the next level until the frequency coupling characteristic impedance matrix of the entire new energy station is obtained.

[0113] In one example, the construction module 22 constructs a corresponding frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix according to the connection mode between the modules.

[0114] Specifically, for low-level modules connected in series, the impedance matrices of each low-level module are superimposed to form the impedance matrix of the high-level module; for low-level modules connected in parallel, the impedance matrices of each low-level module are first inverted and transformed into an admittance matrix, and then the admittance matrices of each low-level module are superimposed to form the admittance matrix of the high-level module, and finally the admittance matrix of the high-level module is inverted to obtain the impedance matrix of the high-level module.

[0115] Yet another embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, an impedance modeling method for a new energy station as in any of the above embodiments is implemented.

[0116] Yet another embodiment of the present application provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the impedance modeling method for a new energy station as in any of the above embodiments.

[0117] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0118] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0119] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0120] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0121] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

[0122] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application 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 embodiments of the present application.

Claims

1. An impedance modeling method for a new energy station, characterized in that: The method comprises: The new energy station is modularly segmented at multiple levels, wherein each level of modular segmentation retains frequency coupling characteristics; A frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix is ​​constructed from a low level to a high level to form a frequency coupling characteristic impedance matrix of the entire new energy site.

2. The impedance modeling method of a new energy station according to claim 1, characterized in that: The multi-level modular segmentation of the new energy station includes: The new energy station is divided into a unit layer, a regional layer and a station layer from low to high.

3. The impedance modeling method of a new energy station according to claim 1, characterized in that: The impedance types of the entire new energy site include grid-connected inverters, transformers and cable lines.

4. The impedance modeling method of a new energy station according to claim 1, characterized in that: In the process of constructing the frequency-coupling characteristic admittance matrix or the frequency-coupling characteristic impedance matrix, it is also necessary to construct the corresponding frequency-coupling characteristic admittance matrix or the frequency-coupling characteristic impedance matrix for the device with non-frequency-coupling characteristics.

5. The impedance modeling method of a new energy station according to claim 1, characterized in that: The step of constructing a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level includes: First, the frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix corresponding to the lowest level is constructed, and then the corresponding frequency coupling characteristic admittance matrix or frequency coupling characteristic impedance matrix is ​​constructed to the upper level until the frequency coupling characteristic impedance matrix of the entire new energy station is obtained.

6. The impedance modeling method of a new energy station according to claim 5, characterized in that: A corresponding frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix is ​​constructed according to the connection mode between the modules.

7. The impedance modeling method of a new energy station according to claim 6, characterized in that: The step of constructing a corresponding frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix according to the connection mode between the modules includes: For low-level modules connected in series, the impedance matrices of each low-level module are superimposed to form the impedance matrix of the high-level module; For low-level modules connected in parallel, the impedance matrices of each low-level module are first inverted and transformed into an admittance matrix, and then the admittance matrices of each low-level module are superimposed to form the admittance matrix of the high-level module. Finally, the admittance matrix of the high-level module is inverted to obtain the impedance matrix of the high-level module.

8. An impedance modeling system for a new energy station, characterized in that: The system comprises: A segmentation module, used for performing multi-level modular segmentation on the new energy station; wherein each level of modular segmentation retains frequency coupling characteristics; The building module is used to build a frequency coupling characteristic admittance matrix or a frequency coupling characteristic impedance matrix from a low level to a high level to form a frequency coupling characteristic impedance matrix of the entire new energy site.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the impedance modeling method for the new energy station as described in any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The computer program product includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the impedance modeling method for a new energy station as described in any one of claims 1-7.

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