Method, device, medium and terminal for coherent aggregation of virtual synchronous generator

Abstract

The present application discloses a method and device, medium, and terminal for quasi-coherent aggregation of virtual synchronous generators, which relates to the field of power grid control technology. The main purpose is to solve the problem that the accuracy of the quasi-coherent division results of each virtual synchronous generator is low, resulting in large errors in the quasi-coherent aggregation results of virtual synchronous generators. The method comprises: obtaining the power angle change data of each virtual synchronous generator contained in the target power station after being subjected to a preset disturbance; selecting two virtual synchronous generators one by one from all virtual synchronous generators, calculating the difference between the power angle change data of the two virtual synchronous generators within a preset time window, and determining them as synchronous generators if the maximum difference is less than or equal to a preset stability margin threshold; dividing the virtual synchronous generators into multiple virtual synchronous generator groups according to the quasi-coherent discrimination results of each virtual synchronous generator pair, and performing aggregation processing to obtain multiple aggregated virtual synchronous generators and generate aggregation parameters.

Description

Technical Field

[0001] The present application relates to the field of power grid control technology, and in particular to a method and device, medium, and terminal for coherent aggregation of virtual synchronous generators. Background Art

[0002] As traditional fossil fuels become increasingly scarce, the development and utilization of new energy technologies such as solar and wind power are expanding, leading to changes in the grid's energy structure and power supply methods. Furthermore, with the large-scale integration of new energy sources into the grid, the operational state of the power system is becoming increasingly complex, making traditional control models based on simple linearization incapable of meeting stable operation requirements. To address this issue, virtual synchronous generator (VSG) technology can be used to control new energy generators, imbuing them with external characteristics similar to synchronous generators, thereby improving the stability of the grid-connected system. Furthermore, for power systems, power stations must meet grid standards before they can be connected to the grid. This determination is based on the characteristics at the access point, without requiring knowledge of their specific internal parameters. Therefore, constructing a dynamic aggregate equivalent model for power stations is a common method used by power system control and dispatch departments to analyze power system stability. However, in existing technologies, the accuracy of the coherence classification results for each virtual synchronous generator is low, resulting in large errors in the virtual synchronous generator coherence aggregation results, which in turn increases the error of the dynamic aggregate equivalent model. Summary of the Invention

[0003] In view of this, the present application provides a method and device, medium, and terminal for quasi-coherence aggregation of virtual synchronous generators. The main purpose is to solve the problem that the accuracy of the quasi-coherence division results of each virtual synchronous generator is low, resulting in large errors in the quasi-coherence aggregation results of virtual synchronous generators.

[0004] According to one aspect of the present application, a method for quasi-coherent aggregation of virtual synchronous generators is provided, comprising:

[0005] Obtaining power angle change data of each virtual synchronous generator included in the target power station within a preset time period after being subjected to a preset disturbance;

[0006] Selecting any two virtual synchronous generators from all virtual synchronous generators one by one as a target virtual synchronous generator pair, and calculating the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair within a preset time window, if the maximum difference in the difference change data is less than or equal to a preset stability margin threshold, then determining that the two virtual synchronous generators in the target virtual synchronous generator pair are synchronous generators, the preset stability margin threshold is determined by using a pre-constructed stability margin threshold adjustment model, the stability margin threshold adjustment model is constructed based on the characteristic values ​​of each virtual synchronous generator included in the target power station, and the preset time window is based on the inertia time constant of the synchronous generator, and is obtained by analogy according to a preset ratio;

[0007] According to the homology discrimination results of each target virtual synchronous generator pair, all virtual synchronous generators are divided into multiple virtual synchronous generator groups, and each of the virtual synchronous generator groups is aggregated to obtain multiple aggregated virtual synchronous generators, and aggregation parameters of each of the aggregated virtual synchronous generators are generated.

[0008] Preferably, before performing the homogeneous tuning determination on the two virtual synchronous generators in the target virtual synchronous generator pair, the method further comprises:

[0009] Obtaining characteristic values ​​of each virtual synchronous generator included in the target power station;

[0010] The minimum absolute value of the real part of each eigenvalue is determined as the dominant eigenvalue of the system.

[0011] ,

[0012] in, represents the dominant eigenvalue of the system, represents the number of virtual synchronous generators, Indicates the The characteristic values ​​of a virtual synchronous generator;

[0013] Calculate the mean of the real parts of the eigenvalues, and determine the mean as the real part of the target eigenvalue.

[0014] ,

[0015] in, Expressed as the real part of the target eigenvalue;

[0016] A stability margin threshold adjustment model is constructed based on the system dominant eigenvalue and the real part of the target eigenvalue.

[0017] ,

[0018] in, Indicates the preset stability margin threshold, Indicates the baseline stability margin threshold.

[0019] Preferably, the obtaining of characteristic values ​​of each virtual synchronous generator included in the target power station includes:

[0020] Construct the output active power expression of the virtual synchronous generator when injecting into the grid,

[0021] ,

[0022] in, represents the output active power of the virtual synchronous generator when it is injected into the grid, represents the voltage at the virtual synchronous generator terminal, Indicates the voltage of the grid, represents the equivalent reactance, represents the power angle of the virtual synchronous generator;

[0023] According to the sine value of the power angle at the equilibrium point, the output active power expression is linearized to obtain the linearized output active power expression, and based on the linearized output active power expression and the rotor motion equation, the state matrix of the virtual synchronous generator is constructed.

[0024] The state matrix is ​​expressed as the following formula:

[0025] ,

[0026] in, represents the state matrix of the virtual synchronous generator, represents the moment of inertia of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator,

[0027] The sine of the power angle at the equilibrium point is , the output active power expression after linearization is,

[0028] ,

[0029] The rotor motion equation is expressed as the following formula,

[0030] ,

[0031] in, represents the angular velocity of the virtual synchronous generator, represents the rated angular velocity of the virtual synchronous generator, Indicates the active power command value of the virtual synchronous generator, Indicates the actual output value of active power of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator;

[0032] A characteristic equation is constructed based on the state matrix, and the characteristic equation is expanded to obtain the expanded characteristic equation.

[0033] ,

[0034] in, represents the characteristic value of the virtual synchronous generator;

[0035] Solving the expanded characteristic equation to obtain an eigenvalue expression of the virtual synchronous generator, and determining the eigenvalue of each virtual synchronous generator included in the target power station based on the eigenvalue expression, the eigenvalue expression is expressed as the following formula,

[0036] .

[0037] Preferably, before performing the homogeneous tuning determination on the two virtual synchronous generators in the target virtual synchronous generator pair, the method further comprises:

[0038] Calculate the inertia time constant of the synchronous generator,

[0039] ,

[0040] in, represents the inertia time constant of the synchronous generator, represents the moment of inertia of the synchronous generator, represents the capacity of the synchronous generator, Indicates the rated speed of the synchronous generator;

[0041] The preset time window is determined according to a preset ratio between the inertia time constant of the synchronous generator and the virtual rotational inertia time constant of the virtual synchronous generator.

[0042] Preferably, the aggregated parameters include aggregated active power loop control parameters, which include aggregated active power command value, aggregated active power actual output value, aggregated damping coefficient, and aggregated moment of inertia. The aggregated active power command value is expressed as the following formula:

[0043] ,

[0044] in, Indicates the aggregated active power command value, Indicates the active power command value of the xth virtual synchronous generator in the virtual synchronous generator group. Indicates the number of virtual synchronous generators contained in the virtual synchronous generator set.

[0045] The actual output value of the aggregated active power is expressed as the following formula:

[0046] ,

[0047] in, Indicates the actual output value of aggregated active power. Indicates the actual output value of active power of the xth virtual synchronous generator in the virtual synchronous generator group.

[0048] The aggregate damping coefficient is expressed as the following formula:

[0049] ,

[0050] in, represents the aggregate damping coefficient, represents the damping coefficient of the xth virtual synchronous generator in the virtual synchronous generator set,

[0051] The aggregate moment of inertia is expressed as the following formula:

[0052] ,

[0053] in, represents the aggregate moment of inertia, It represents the moment of inertia of the xth virtual synchronous generator in the virtual synchronous generator set.

[0054] Preferably, the aggregation parameters include aggregation reactive loop control parameters, the aggregation reactive loop control parameters include aggregation reactive droop coefficient, aggregation reactive integral coefficient, aggregation reactive power command value, aggregation reactive power actual output value, the aggregation reactive droop coefficient is expressed as the following formula,

[0055] ,

[0056] in, represents the aggregate reactive power droop coefficient, It represents the reactive power droop coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0057] The aggregate reactive integral coefficient is expressed as the following formula:

[0058] ,

[0059] in, Represents the aggregate reactive power integral coefficient, It represents the reactive integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0060] The aggregate reactive power command value is expressed as the following formula:

[0061] ,

[0062] in, Indicates the aggregated reactive power command value, Indicates the reactive power command value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0063] The actual output value of the aggregated reactive power is expressed as the following formula:

[0064] ,

[0065] in, Indicates the actual output value of aggregated reactive power. It represents the actual reactive power output value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0066] Preferably, the aggregation parameters include aggregation voltage and current dual closed-loop control parameters, and the aggregation voltage and current dual closed-loop control parameters include aggregation current loop proportional coefficient, aggregation voltage loop proportional coefficient, and aggregation voltage loop integral coefficient. The aggregation current loop proportional coefficient is expressed as the following formula:

[0067] ,

[0068] in, represents the proportional coefficient of the aggregate current loop, Indicates the aggregate AC side filter inductance, It represents the current loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set. It represents the AC side filter inductance of the xth virtual synchronous generator in the virtual synchronous generator set.

[0069] The aggregate voltage loop proportional coefficient is expressed as the following formula:

[0070] ,

[0071] in, Represents the proportional coefficient of the aggregate voltage loop, It represents the voltage loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0072] The integral coefficient of the aggregation voltage loop is expressed as the following formula:

[0073] ,

[0074] in, represents the integral coefficient of the aggregate voltage loop, It represents the voltage loop integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0075] Preferably, the aggregation parameters include aggregation main circuit parameters, and the aggregation main circuit parameters include the inverse of the aggregation AC side filter inductance coefficient and the aggregation AC side filter capacitance coefficient. The inverse of the aggregation AC side filter inductance coefficient is expressed as the following formula:

[0076] ,

[0077] The aggregate AC side filter capacitance coefficient is expressed as the following formula:

[0078] ,

[0079] in, Indicates the aggregate AC side filter capacitance coefficient, It represents the AC side filter capacitance coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0080] According to another aspect of the present application, a quasi-coherent aggregation device for a virtual synchronous generator is provided, comprising:

[0081] A data acquisition module is used to obtain power angle change data of each virtual synchronous generator included in the target power station within a preset time period after being subjected to a preset disturbance;

[0082] a quasi-coherence discrimination module, configured to select any two virtual synchronous generators from all virtual synchronous generators one by one as a target virtual synchronous generator pair, and calculate, within a preset time window, difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair; if a maximum difference in the difference change data is less than or equal to a preset stability margin threshold, the two virtual synchronous generators in the target virtual synchronous generator pair are determined to be coherent generators, wherein the preset stability margin threshold is determined using a pre-constructed stability margin threshold adjustment model, which is constructed based on characteristic values ​​of each virtual synchronous generator included in the target power station; and the preset time window is obtained by analogy according to a preset ratio based on the inertia time constant of the synchronous generator;

[0083] The aggregation module is used to divide all virtual synchronous generators into multiple virtual synchronous generator groups based on the similarity judgment results of each target virtual synchronous generator pair, and aggregate each of the virtual synchronous generator groups to obtain multiple aggregated virtual synchronous generators, and generate aggregation parameters for each of the aggregated virtual synchronous generators.

[0084] Preferably, before the homophonic discrimination module, the device further includes a stability margin threshold determination module, which is configured to:

[0085] Obtaining characteristic values ​​of each virtual synchronous generator included in the target power station;

[0086] The minimum absolute value of the real part of each eigenvalue is determined as the dominant eigenvalue of the system.

[0087] ,

[0088] in, represents the dominant eigenvalue of the system, represents the number of virtual synchronous generators, Indicates the The characteristic values ​​of a virtual synchronous generator;

[0089] Calculate the mean of the real parts of the eigenvalues, and determine the mean as the real part of the target eigenvalue.

[0090] ,

[0091] in, Expressed as the real part of the target eigenvalue;

[0092] A stability margin threshold adjustment model is constructed based on the system dominant eigenvalue and the real part of the target eigenvalue.

[0093] ,

[0094] in, Indicates the preset stability margin threshold, Indicates the baseline stability margin threshold.

[0095] Preferably, the stability margin threshold determination module is further configured to:

[0096] Construct the output active power expression of the virtual synchronous generator when injecting into the grid,

[0097] ,

[0098] in, represents the output active power of the virtual synchronous generator when it is injected into the grid, represents the voltage at the virtual synchronous generator terminal, Indicates the voltage of the grid, represents the equivalent reactance, represents the power angle of the virtual synchronous generator;

[0099] According to the sine value of the power angle at the equilibrium point, the output active power expression is linearized to obtain the linearized output active power expression, and based on the linearized output active power expression and the rotor motion equation, the state matrix of the virtual synchronous generator is constructed.

[0100] The state matrix is ​​expressed as the following formula:

[0101] ,

[0102] in, represents the state matrix of the virtual synchronous generator, represents the moment of inertia of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator,

[0103] The sine of the power angle at the equilibrium point is , the output active power expression after linearization is,

[0104] ,

[0105] The rotor motion equation is expressed as the following formula,

[0106] ,

[0107] in, represents the angular velocity of the virtual synchronous generator, represents the rated angular velocity of the virtual synchronous generator, Indicates the active power command value of the virtual synchronous generator, Indicates the actual output value of active power of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator;

[0108] A characteristic equation is constructed based on the state matrix, and the characteristic equation is expanded to obtain the expanded characteristic equation.

[0109] ,

[0110] in, represents the characteristic value of the virtual synchronous generator;

[0111] Solving the expanded characteristic equation to obtain an eigenvalue expression of the virtual synchronous generator, and determining the eigenvalue of each virtual synchronous generator included in the target power station based on the eigenvalue expression, the eigenvalue expression is expressed as the following formula,

[0112] .

[0113] Preferably, before the homophonic discrimination module, the device further includes a time window determination module, which is configured to:

[0114] Calculate the inertia time constant of the synchronous generator,

[0115] ,

[0116] in, represents the inertia time constant of the synchronous generator, represents the moment of inertia of the synchronous generator, represents the capacity of the synchronous generator, Indicates the rated speed of the synchronous generator;

[0117] The preset time window is determined according to a preset ratio between the inertia time constant of the synchronous generator and the virtual rotational inertia time constant of the virtual synchronous generator.

[0118] Preferably, the aggregated parameters include aggregated active power loop control parameters, which include aggregated active power command value, aggregated active power actual output value, aggregated damping coefficient, and aggregated moment of inertia. The aggregated active power command value is expressed as the following formula:

[0119] ,

[0120] in, Indicates the aggregated active power command value, Indicates the active power command value of the xth virtual synchronous generator in the virtual synchronous generator group. Indicates the number of virtual synchronous generators contained in the virtual synchronous generator set.

[0121] The actual output value of the aggregated active power is expressed as the following formula:

[0122] ,

[0123] in, Indicates the actual output value of aggregated active power. Indicates the actual output value of active power of the xth virtual synchronous generator in the virtual synchronous generator group.

[0124] The aggregate damping coefficient is expressed as the following formula:

[0125] ,

[0126] in, represents the aggregate damping coefficient, represents the damping coefficient of the xth virtual synchronous generator in the virtual synchronous generator set,

[0127] The aggregate moment of inertia is expressed as the following formula:

[0128] ,

[0129] in, represents the aggregate moment of inertia, It represents the moment of inertia of the xth virtual synchronous generator in the virtual synchronous generator set.

[0130] Preferably, the aggregation parameters include aggregation reactive loop control parameters, the aggregation reactive loop control parameters include aggregation reactive droop coefficient, aggregation reactive integral coefficient, aggregation reactive power command value, aggregation reactive power actual output value, the aggregation reactive droop coefficient is expressed as the following formula,

[0131] ,

[0132] in, represents the aggregate reactive power droop coefficient, It represents the reactive power droop coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0133] The aggregate reactive integral coefficient is expressed as the following formula:

[0134] ,

[0135] in, Represents the aggregate reactive power integral coefficient, It represents the reactive integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0136] The aggregate reactive power command value is expressed as the following formula:

[0137] ,

[0138] in, Indicates the aggregated reactive power command value, Indicates the reactive power command value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0139] The actual output value of the aggregated reactive power is expressed as the following formula:

[0140] ,

[0141] in, Indicates the actual output value of aggregated reactive power. It represents the actual reactive power output value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0142] Preferably, the aggregation parameters include aggregation voltage and current dual closed-loop control parameters, and the aggregation voltage and current dual closed-loop control parameters include aggregation current loop proportional coefficient, aggregation voltage loop proportional coefficient, and aggregation voltage loop integral coefficient. The aggregation current loop proportional coefficient is expressed as the following formula:

[0143] ,

[0144] in, represents the proportional coefficient of the aggregate current loop, Indicates the aggregate AC side filter inductance, It represents the current loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set. It represents the AC side filter inductance of the xth virtual synchronous generator in the virtual synchronous generator set.

[0145] The aggregate voltage loop proportional coefficient is expressed as the following formula:

[0146] ,

[0147] in, Represents the proportional coefficient of the aggregate voltage loop, It represents the voltage loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0148] The integral coefficient of the aggregation voltage loop is expressed as the following formula:

[0149] ,

[0150] in, represents the integral coefficient of the aggregate voltage loop, It represents the voltage loop integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0151] Preferably, the aggregation parameters include aggregation main circuit parameters, and the aggregation main circuit parameters include the inverse of the aggregation AC side filter inductance coefficient and the aggregation AC side filter capacitance coefficient. The inverse of the aggregation AC side filter inductance coefficient is expressed as the following formula:

[0152] ,

[0153] The aggregate AC side filter capacitance coefficient is expressed as the following formula:

[0154] ,

[0155] in, Indicates the aggregate AC side filter capacitance coefficient, It represents the AC side filter capacitance coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0156] According to another aspect of the present application, a storage medium is provided, in which at least one executable instruction is stored. The executable instruction enables a processor to execute operations corresponding to the aforementioned coherent aggregation method of a virtual synchronous generator.

[0157] According to another aspect of the present application, there is provided a terminal, comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus;

[0158] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned method for quasi-coherent aggregation of virtual synchronous generators.

[0159] By means of the above technical solution, the technical solution provided by the embodiment of the present application has at least the following advantages:

[0160] The present application provides a method and device, medium and terminal for coherent aggregation of virtual synchronous generators, which first obtains the power angle change data of each virtual synchronous generator contained in the target power station within a preset time period after being subjected to a preset disturbance; secondly, any two virtual synchronous generators are selected one by one from all virtual synchronous generators as target virtual synchronous generator pairs, and the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair is calculated within a preset time window. If the maximum difference in the difference change data is less than or equal to a preset stability margin threshold, it is determined that the two virtual synchronous generators in the target virtual synchronous generator pair are stable. The target power station is a synchronous generator, and the preset stability margin threshold is determined by using a pre-constructed stability margin threshold adjustment model. The stability margin threshold adjustment model is constructed based on the characteristic values ​​of each virtual synchronous generator included in the target power station. The preset time window is based on the inertia time constant of the synchronous generator and is obtained by analogy according to a preset ratio. Finally, according to the coherence discrimination results of each target virtual synchronous generator pair, all virtual synchronous generators are divided into multiple virtual synchronous generator groups, and each of the virtual synchronous generator groups is aggregated to obtain multiple aggregated virtual synchronous generators, and aggregation parameters of each aggregated virtual synchronous generator are generated. Compared with the prior art, the embodiment of the present application constructs a stability margin threshold adjustment model in advance based on the characteristic values ​​of each virtual synchronous generator contained in the target power station to determine a preset stability margin threshold, and performs pairwise synchronization judgment on the virtual synchronous generators according to the threshold, and then divides all virtual synchronous generators into multiple virtual synchronous generator groups according to the pairwise synchronization judgment results, and aggregates them into aggregated virtual synchronous generators. Since the preset stability margin threshold used in the class synchronization judgment is determined based on the characteristic values ​​of each virtual synchronous generator contained in the target power station, it meets the actual environment and stability margin requirements of different power plants, improves the accuracy of the class synchronization judgment results, thereby improving the accuracy of the class synchronization aggregation results of the virtual synchronous generators, and makes the accuracy of the dynamic aggregation equivalence model higher.

[0161] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0162] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0163] Figure 1 A flowchart of a method for quasi-coherent aggregation of a virtual synchronous generator provided in an embodiment of the present application is shown;

[0164] Figure 2 A flow chart for determining a stability margin threshold value provided by an embodiment of the present application is shown;

[0165] Figure 3 A flow chart for determining a time window provided in an embodiment of the present application is shown;

[0166] Figure 4 A block diagram of a quasi-coherent aggregation device for a virtual synchronous generator provided in an embodiment of the present application is shown;

[0167] Figure 5 A schematic diagram of the structure of a terminal provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0168] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0169] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0170] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0171] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0172] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0173] Embodiments of the present application may be applied to a computer system / server that is operable with numerous other general-purpose or special-purpose computing system environments or configurations. Examples of well-known computing systems, environments, and / or configurations suitable for use with the computer system / server include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, minicomputer systems, mainframe computer systems, and distributed cloud computing technology environments including any of the foregoing.

[0174] Computer systems / servers may be described in the general context of computer-system-executable instructions, such as program modules, executed by the computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, and the like that perform specific tasks or implement specific abstract data types. Computer systems / servers may be implemented in distributed cloud computing environments, where tasks are performed by remote processing devices linked through a communications network. In distributed cloud computing environments, program modules may reside on local or remote computer system storage media, including storage devices.

[0175] The embodiment of the present application provides a method for quasi-coherent aggregation of virtual synchronous generators, such as Figure 1 As shown, the method includes:

[0176] 101. Obtain power angle change data of each virtual synchronous generator included in a target power station within a preset time period after being subjected to a preset disturbance.

[0177] It should be noted that a power station may contain multiple renewable energy generators. Due to the unstable output characteristics of renewable energy generators, a virtual synchronous generator can be configured for each renewable energy generator to control the renewable energy generator so that it has properties similar to the external characteristics of a synchronous generator, thereby improving the stability of the grid-connected system.

[0178] The power angle change data represents the difference between the power angle data of the virtual synchronous generator after being subjected to a preset disturbance and the initial power angle data, i.e., relative power angle data. The data can be recorded in the form of a change curve graph or a table. The preset disturbance can be a fault disturbance such as a voltage drop or single-phase ground fault. In this embodiment of the present application, the current execution end can be a grid stability control module.

[0179] 102. Select any two virtual synchronous generators from all virtual synchronous generators one by one as the target virtual synchronous generator pair, and calculate the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair within a preset time window. If the maximum difference in the difference change data is less than or equal to a preset stability margin threshold, the two virtual synchronous generators in the target virtual synchronous generator pair are determined to be synchronous generators.

[0180] Among them, the preset stability margin threshold is determined by using a pre-built stability margin threshold adjustment model. The stability margin threshold adjustment model is constructed based on the characteristic values ​​of each virtual synchronous generator contained in the target power station. The preset time window is based on the inertia time constant of the synchronous generator and is obtained by analogy according to a preset ratio.

[0181] It can be understood that in the embodiment of the present application, the similarity determination is performed on every two virtual generators in all virtual synchronous generators based on the preset time window and the preset stability margin threshold. Specifically, the determination can be performed according to the following formula:

[0182] ,

[0183] in, Indicates the preset time window, Indicates the The power angle change data of the virtual generator, Indicates the The power angle change data of the virtual generator, Represents the preset stability margin threshold. This formula calculates the difference in power angle variation between the two virtual synchronous generators in the target virtual synchronous generator pair within a preset time window. If the maximum difference in the difference is less than or equal to the preset stability margin threshold, the two virtual synchronous generators in the target virtual synchronous generator pair are considered to be synchronized generators.

[0184] 103. Based on the homogeneity discrimination results of each target virtual synchronous generator pair, all virtual synchronous generators are divided into multiple virtual synchronous generator groups, and each virtual synchronous generator group is aggregated to obtain multiple aggregated virtual synchronous generators, and aggregation parameters of each aggregated virtual synchronous generator are generated.

[0185] For example, the target power station has a total of 5 virtual synchronous generators, namely VSG1-VSG5. Any two virtual synchronous generators are selected one by one as the target virtual synchronous generator pair, and the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair is calculated within a preset time window, and the maximum difference is selected from the difference change data, as shown in Table 1.

[0186] Table 1 Maximum difference between virtual synchronous generator pairs

[0187]

[0188] The stability margin threshold is set to 0.49. It can be seen from the table that there are 5 pairs of synchronous generators, namely VSG1 and VSG2, VSG1 and VSG4, VSG2 and VSG4, VSG3 and VSG5, and VSG4 and VSG5. It should be noted that the stability margin threshold between each two virtual synchronous generators must be less than the preset stability margin threshold before they can be divided into the same virtual synchronous generator group. Therefore, the virtual generators VSG1-VSG5 can be divided into two groups of virtual synchronous generator groups, namely VSG1, VSG2, VSG4 and VSG3, VSG5. Furthermore, the two groups of virtual synchronous generator groups are aggregated to obtain two aggregated virtual synchronous generators, and aggregated parameters are generated, which can include aggregated active loop control parameters, aggregated reactive loop control parameters, aggregated voltage and current dual closed-loop control parameters, aggregated main circuit parameters, etc.

[0189] Compared with the prior art, the embodiment of the present application constructs a stability margin threshold adjustment model in advance based on the characteristic values ​​of each virtual synchronous generator contained in the target power station to determine a preset stability margin threshold, and performs pairwise synchronization judgment on the virtual synchronous generators according to the threshold, and then divides all virtual synchronous generators into multiple virtual synchronous generator groups according to the pairwise synchronization judgment results, and aggregates them into aggregated virtual synchronous generators. Since the preset stability margin threshold used in the class synchronization judgment is determined based on the characteristic values ​​of each virtual synchronous generator contained in the target power station, it meets the actual environment and stability margin requirements of different power plants, improves the accuracy of the class synchronization judgment results, thereby improving the accuracy of the class synchronization aggregation results of the virtual synchronous generators, and makes the accuracy of the dynamic aggregation equivalence model higher.

[0190] In an embodiment of the present application, in order to further define and illustrate, Figure 2 As shown, before step 102 of the embodiment performs similarity determination on the two virtual synchronous generators in the target virtual synchronous generator pair, the embodiment method further includes:

[0191] 201. Obtain characteristic values ​​of each virtual synchronous generator included in the target power station.

[0192] Specifically, first, construct the output active power expression of the virtual synchronous generator when injecting into the grid,

[0193] ,

[0194] in, represents the output active power of the virtual synchronous generator when it is injected into the grid, represents the voltage at the virtual synchronous generator terminal, Indicates the voltage of the grid, represents the equivalent reactance, Represents the power angle of the virtual synchronous generator.

[0195] Furthermore, according to the sine value of the power angle at the equilibrium point , linearize the output active power expression to obtain the linearized output active power expression,

[0196] .

[0197] Furthermore, based on the linearized output active power expression and the rotor motion equation, the state matrix and input matrix of the virtual synchronous generator are constructed.

[0198] The state matrix is ​​expressed as the following formula,

[0199] ,

[0200] in, represents the state matrix of the virtual synchronous generator, represents the moment of inertia of the virtual synchronous generator, It is necessary to explain that the elements in the state matrix A reflect the inherent dynamic characteristics of the system. 21 The element represents the effect of electrical power on the power angle, A 22 The element represents the damping effect,

[0201] Input matrix, expressed as the following formula,

[0202] ,

[0203] The input matrix B describes the influence of the input variables on the system state, mainly considering the influence of the active power reference value on the angular velocity.

[0204] It should be noted that the rotor motion equation is expressed as the following formula:

[0205] ,

[0206] in, represents the angular velocity of the virtual synchronous generator, represents the rated angular velocity of the virtual synchronous generator, Indicates the active power command value of the virtual synchronous generator, Indicates the actual output value of active power of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator.

[0207] Furthermore, the characteristic equation is constructed based on the state matrix , and expand the characteristic equation to obtain the expanded characteristic equation,

[0208] ,

[0209] in, represents the characteristic value of the virtual synchronous generator, I express.

[0210] Finally, the expanded characteristic equation is solved to obtain the eigenvalue expression of the virtual synchronous generator, so as to determine the eigenvalue of each virtual synchronous generator contained in the target power station based on the eigenvalue expression. The eigenvalue expression is expressed as the following formula:

[0211] .

[0212] In addition, based on the state matrix and input matrix, a state space model can also be constructed.

[0213] ,

[0214] in, Indicates the reactive power command value.

[0215] 202. The minimum absolute value of the real part of each eigenvalue is determined as the dominant eigenvalue of the system.

[0216] ,

[0217] in, represents the dominant eigenvalue of the system, represents the number of virtual synchronous generators, Indicates the The eigenvalues ​​of a virtual synchronous generator.

[0218] 203. Calculate the mean of the real part of each eigenvalue and determine the mean as the real part of the target eigenvalue.

[0219] ,

[0220] in, Expressed as the real part of the target eigenvalue.

[0221] 204. Construct a stability margin threshold adjustment model based on the system dominant eigenvalue and the real part of the target eigenvalue.

[0222] ,

[0223] in, Indicates the preset stability margin threshold, Indicates the baseline stability margin threshold.

[0224] In an embodiment of the present application, in order to further define and illustrate, Figure 3 As shown, before step 102 of the embodiment performs similarity determination on the two virtual synchronous generators in the target virtual synchronous generator pair, the embodiment method further includes:

[0225] 301. Calculate the inertia time constant of a synchronous generator.

[0226] ,

[0227] in, represents the inertia time constant of the synchronous generator, represents the moment of inertia of the synchronous generator, represents the capacity of the synchronous generator, Indicates the rated speed of the synchronous generator.

[0228] 302. Determine a preset time window according to a preset ratio between the inertia time constant of the synchronous generator and the virtual rotational inertia time constant of the virtual synchronous generator.

[0229] Specifically, the preset ratio can be set to 10-100, that is, ,in, Indicates the preset ratio, represents the virtual rotation inertia time constant of the virtual synchronous generator. Based on this, the preset time window can be set to .

[0230] It should be noted that, since the active power control loop of the virtual synchronous generator simulates the mechanical equation of the synchronous generator, the virtual rotational inertia time constant of the virtual synchronous generator can be expressed as the following formula:

[0231] ,

[0232] in, represents the virtual moment of inertia of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator.

[0233] In one embodiment of the present application, for further limitation and explanation, the aggregated parameters of the aggregated virtual synchronous generator generated in step 103 of the embodiment include four parts: aggregated active loop control parameters, aggregated reactive loop control parameters, aggregated voltage and current dual closed-loop control parameters, and aggregated main circuit parameters.

[0234] 1. Aggregate active power loop control parameters, including aggregate active power command value, aggregate active power actual output value, aggregate damping coefficient, and aggregate rotational inertia.

[0235] It should be noted that, first, according to the rotor motion equation, the active power control loop expression of the xth virtual synchronous generator in the virtual synchronous generator group is constructed.

[0236] ,

[0237] in, represents the moment of inertia of the xth virtual synchronous generator in the virtual synchronous generator set, represents the angular velocity of the virtual synchronous generator, represents the rated angular velocity of the xth virtual synchronous generator in the virtual synchronous generator set, Indicates the active power command value of the xth virtual synchronous generator in the virtual synchronous generator group. Indicates the actual output value of active power of the xth virtual synchronous generator in the virtual synchronous generator group. It represents the damping coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0238] Furthermore, since the virtual synchronous generators run at the common bus, the rated frequencies of their output voltages are the same, i.e. .

[0239] Furthermore, when the system is in steady state, let the differential term be 0, and combine the active power control loop expression of the xth virtual synchronous generator in the virtual synchronous generator group and the rated frequency expression of the output voltage to obtain the following expression:

[0240] ,

[0241] Therefore, the aggregate active power command value is expressed as the following formula:

[0242] ,

[0243] in, Indicates the aggregated active power command value, Indicates the active power command value of the xth virtual synchronous generator in the virtual synchronous generator group. Indicates the number of virtual synchronous generators contained in the quasi-synchronous generator set,

[0244] The actual output value of aggregated active power is expressed as the following formula:

[0245] ,

[0246] in, Indicates the actual output value of aggregated active power. Indicates the actual output value of active power of the xth virtual synchronous generator in the virtual synchronous generator group.

[0247] The aggregate damping coefficient is expressed as follows,

[0248] ,

[0249] in, represents the aggregate damping coefficient, It represents the damping coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0250] Similarly, construct the active power control loop expression of the aggregated virtual synchronous generator,

[0251] ,

[0252] in, represents the moment of inertia of the aggregated virtual synchronous generator, represents the angular velocity of the aggregated virtual synchronous generator, represents the rated angular velocity of the aggregated virtual synchronous generator, Indicates the active power command value of the aggregated virtual synchronous generator, Indicates the actual output value of active power of the aggregated virtual synchronous generator, represents the damping coefficient of the aggregated virtual synchronous generator.

[0253] By combining the active power control loop expression of the aggregated virtual synchronous generator and the active power control loop expression of the x-th virtual synchronous generator in the virtual synchronous generator group, the aggregate moment of inertia can be obtained, which is expressed as the following formula:

[0254] ,

[0255] in, represents the aggregate moment of inertia, It represents the moment of inertia of the xth virtual synchronous generator in the virtual synchronous generator set.

[0256] 2. Aggregate reactive power loop control parameters, including aggregate reactive power droop coefficient, aggregate reactive power integral coefficient, aggregate reactive power command value, and aggregate reactive power actual output value.

[0257] It should be noted that, first, the reactive power control loop expression of the xth virtual synchronous generator in the virtual synchronous generator group is constructed.

[0258] ,

[0259] in, It represents the output voltage amplitude of the xth virtual synchronous generator in the virtual synchronous generator set. It represents the droop coefficient of the xth virtual synchronous generator in the virtual synchronous generator set. It represents the reactive integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group. Indicates the output voltage command value of the xth virtual synchronous generator in the virtual synchronous generator set. Indicates the actual output voltage value of the xth virtual synchronous generator in the virtual synchronous generator set. Indicates the output reactive power command value of the xth virtual synchronous generator in the virtual synchronous generator group. It represents the actual value of the output reactive power of the xth virtual synchronous generator in the virtual synchronous generator group.

[0260] Furthermore, since the virtual synchronous generators run at the common bus, and there is an approximate relationship , therefore, the amplitude of the output voltage of each virtual synchronous generator is the same, that is,

[0261] .

[0262] By combining the reactive power control loop expression of the xth virtual synchronous generator in the virtual synchronous generator group and the amplitude expression of the output voltage, the following expression can be obtained:

[0263] ,

[0264] Therefore, the aggregate reactive power droop coefficient is expressed as the following formula:

[0265] ,

[0266] in, represents the aggregate reactive power droop coefficient, It represents the reactive power droop coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0267] The aggregate reactive power integral coefficient is expressed as the following formula:

[0268] ,

[0269] in, Represents the aggregate reactive power integral coefficient, It represents the reactive integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0270] The aggregate reactive power command value is expressed as the following formula:

[0271] ,

[0272] in, Indicates the aggregated reactive power command value, Indicates the reactive power command value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0273] The actual output value of the aggregated reactive power is expressed as the following formula:

[0274] ,

[0275] in, Indicates the actual output value of aggregated reactive power. It represents the actual reactive power output value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0276] 3. Aggregation voltage and current dual closed-loop control parameters, including aggregation current loop proportional coefficient, aggregation voltage loop proportional coefficient, aggregation voltage loop integral coefficient.

[0277] It should be noted that, first, the current open-loop transfer functions of each virtual synchronous generator in the virtual synchronous generator group are superimposed to obtain the open-loop transfer function expression of the current loop of the equivalent aggregated virtual synchronous generator.

[0278] ,

[0279] in, s represents the Laplace operator.

[0280] Furthermore, the current loop transfer functions of each virtual synchronous generator in the virtual synchronous generator group are superimposed to obtain the closed-loop transfer function expression of the current loop of the equivalent aggregated virtual synchronous generator.

[0281] .

[0282] By combining the open-loop transfer function expression of the current loop of the equivalent aggregated virtual synchronous generator and the transfer function expression of the current loop of the equivalent aggregated virtual synchronous generator, the proportional coefficient of the aggregated current loop can be obtained as follows:

[0283] ,

[0284] in, represents the proportional coefficient of the aggregate current loop, Indicates the aggregate AC side filter inductance, It represents the current loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set. It represents the AC side filter inductance of the xth virtual synchronous generator in the virtual synchronous generator set.

[0285] Similarly, the voltage loop open-loop transfer functions of each virtual synchronous generator in the virtual synchronous generator group are superimposed to obtain the open-loop transfer function expression of the voltage loop of the aggregated virtual synchronous generator.

[0286] ,

[0287] And, the voltage loop transfer functions of each virtual synchronous generator in the virtual synchronous generator group are superimposed to obtain the closed-loop transfer function expression of the voltage loop of the aggregated virtual synchronous generator,

[0288] ,

[0289] Therefore, the proportional coefficient of the aggregate voltage loop is expressed as the following formula:

[0290] ,

[0291] in, Represents the proportional coefficient of the aggregate voltage loop, It represents the voltage loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0292] The integral coefficient of the aggregate voltage loop is expressed as the following formula:

[0293] ,

[0294] in, represents the integral coefficient of the aggregate voltage loop, It represents the voltage loop integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0295] 4. Aggregation main circuit parameters, including the inverse of the aggregation AC side filter inductance coefficient and the aggregation AC side filter capacitance coefficient.

[0296] The inverse of the AC side filter inductance coefficient is expressed as the following formula:

[0297] ,

[0298] The aggregate AC side filter capacitance coefficient is expressed as the following formula:

[0299] ,

[0300] in, Indicates the aggregate AC side filter capacitance coefficient, It represents the AC side filter capacitance coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0301] The present application provides a quasi-coherent aggregation method for virtual synchronous generators, which first obtains the power angle change data of each virtual synchronous generator contained in the target power station within a preset time period after being subjected to a preset disturbance; secondly, any two virtual synchronous generators are selected one by one from all virtual synchronous generators as target virtual synchronous generator pairs, and the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair is calculated within a preset time window. If the maximum difference in the difference change data is less than or equal to a preset stability margin threshold, the two virtual synchronous generators in the target virtual synchronous generator pair are determined to be coherent generators. Motor, the preset stability margin threshold is determined by using a pre-constructed stability margin threshold adjustment model, the stability margin threshold adjustment model is constructed based on the characteristic values ​​of each virtual synchronous generator contained in the target power station, and the preset time window is based on the inertia time constant of the synchronous generator, obtained by analogy according to a preset ratio; finally, according to the analog adjustment judgment results of each target virtual synchronous generator pair, all virtual synchronous generators are divided into multiple virtual synchronous generator groups, and each of the virtual synchronous generator groups is aggregated to obtain multiple aggregated virtual synchronous generators, and the aggregation parameters of each aggregated virtual synchronous generator are generated. Compared with the prior art, the embodiment of the present application constructs a stability margin threshold adjustment model in advance based on the characteristic values ​​of each virtual synchronous generator contained in the target power station to determine a preset stability margin threshold, and performs pairwise synchronization judgment on the virtual synchronous generators according to the threshold, and then divides all virtual synchronous generators into multiple virtual synchronous generator groups according to the pairwise synchronization judgment results, and aggregates them into aggregated virtual synchronous generators. Since the preset stability margin threshold used in the class synchronization judgment is determined based on the characteristic values ​​of each virtual synchronous generator contained in the target power station, it meets the actual environment and stability margin requirements of different power plants, improves the accuracy of the class synchronization judgment results, thereby improving the accuracy of the class synchronization aggregation results of the virtual synchronous generators, and makes the accuracy of the dynamic aggregation equivalence model higher.

[0302] Furthermore, as a response to the above Figure 1 The embodiment of the present application provides a virtual synchronous generator quasi-coherent aggregation device, such as Figure 4 As shown, the device includes:

[0303] Data acquisition module 41, similarity identification module 42, aggregation module 43;

[0304] The data acquisition module 41 is used to obtain the power angle change data of each virtual synchronous generator included in the target power station within a preset time period after being subjected to a preset disturbance;

[0305] a quasi-coherent determination module 42 for selecting any two virtual synchronous generators from all virtual synchronous generators as a target virtual synchronous generator pair, and calculating difference change data between power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair within a preset time window; if a maximum difference in the difference change data is less than or equal to a preset stability margin threshold, then determining that the two virtual synchronous generators in the target virtual synchronous generator pair are coherent generators, wherein the preset stability margin threshold is determined using a pre-constructed stability margin threshold adjustment model, which is constructed based on characteristic values ​​of each virtual synchronous generator included in the target power station, and the preset time window is obtained by analogy according to a preset ratio based on the inertia time constant of the synchronous generator;

[0306] The aggregation module 43 is used to divide all virtual synchronous generators into multiple virtual synchronous generator groups based on the similarity judgment results of each target virtual synchronous generator pair, and aggregate each of the virtual synchronous generator groups to obtain multiple aggregated virtual synchronous generators, and generate aggregation parameters for each of the aggregated virtual synchronous generators.

[0307] In a specific application scenario, the analog-to-analog discrimination module and the device further include a stability margin threshold determination module, which is configured to:

[0308] Obtaining characteristic values ​​of each virtual synchronous generator included in the target power station;

[0309] The minimum absolute value of the real part of each eigenvalue is determined as the dominant eigenvalue of the system.

[0310] ,

[0311] in, represents the dominant eigenvalue of the system, represents the number of virtual synchronous generators, Indicates the The characteristic values ​​of a virtual synchronous generator;

[0312] Calculate the mean of the real parts of the eigenvalues, and determine the mean as the real part of the target eigenvalue.

[0313] ,

[0314] in, Expressed as the real part of the target eigenvalue;

[0315] A stability margin threshold adjustment model is constructed based on the system dominant eigenvalue and the real part of the target eigenvalue.

[0316] ,

[0317] in, Indicates the preset stability margin threshold, Indicates the baseline stability margin threshold.

[0318] In a specific application scenario, the stability margin threshold determination module is further used to:

[0319] Construct the output active power expression of the virtual synchronous generator when injecting into the grid,

[0320] ,

[0321] in, represents the output active power of the virtual synchronous generator when it is injected into the grid, represents the voltage at the virtual synchronous generator terminal, Indicates the voltage of the grid, represents the equivalent reactance, represents the power angle of the virtual synchronous generator;

[0322] According to the sine value of the power angle at the equilibrium point, the output active power expression is linearized to obtain the linearized output active power expression, and based on the linearized output active power expression and the rotor motion equation, the state matrix of the virtual synchronous generator is constructed.

[0323] The state matrix is ​​expressed as the following formula:

[0324] ,

[0325] in, represents the state matrix of the virtual synchronous generator, represents the moment of inertia of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator,

[0326] The sine of the power angle at the equilibrium point is , the output active power expression after linearization is,

[0327] ,

[0328] The rotor motion equation is expressed as the following formula,

[0329] ,

[0330] in, represents the angular velocity of the virtual synchronous generator, represents the rated angular velocity of the virtual synchronous generator, Indicates the active power command value of the virtual synchronous generator, Indicates the actual output value of active power of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator;

[0331] A characteristic equation is constructed based on the state matrix, and the characteristic equation is expanded to obtain the expanded characteristic equation.

[0332] ,

[0333] in, represents the characteristic value of the virtual synchronous generator;

[0334] Solving the expanded characteristic equation to obtain an eigenvalue expression of the virtual synchronous generator, and determining the eigenvalue of each virtual synchronous generator included in the target power station based on the eigenvalue expression, the eigenvalue expression is expressed as the following formula,

[0335] .

[0336] In a specific application scenario, before the homophonic discrimination module, the device further includes a time window determination module, which is configured to:

[0337] Calculate the inertia time constant of the synchronous generator,

[0338] ,

[0339] in, represents the inertia time constant of the synchronous generator, represents the moment of inertia of the synchronous generator, represents the capacity of the synchronous generator, Indicates the rated speed of the synchronous generator;

[0340] The preset time window is determined according to a preset ratio between the inertia time constant of the synchronous generator and the virtual rotational inertia time constant of the virtual synchronous generator.

[0341] In a specific application scenario, the aggregated parameters include aggregated active power loop control parameters, which include aggregated active power command value, aggregated active power actual output value, aggregated damping coefficient, and aggregated moment of inertia. The aggregated active power command value is expressed as the following formula:

[0342] ,

[0343] in, Indicates the aggregated active power command value, Indicates the active power command value of the xth virtual synchronous generator in the virtual synchronous generator group. Indicates the number of virtual synchronous generators contained in the virtual synchronous generator set.

[0344] The actual output value of the aggregated active power is expressed as the following formula:

[0345] ,

[0346] in, Indicates the actual output value of aggregated active power. Indicates the actual output value of active power of the xth virtual synchronous generator in the virtual synchronous generator group.

[0347] The aggregate damping coefficient is expressed as the following formula:

[0348] ,

[0349] in, represents the aggregate damping coefficient, represents the damping coefficient of the xth virtual synchronous generator in the virtual synchronous generator set,

[0350] The aggregate moment of inertia is expressed as the following formula:

[0351] ,

[0352] in, represents the aggregate moment of inertia, It represents the moment of inertia of the xth virtual synchronous generator in the virtual synchronous generator set.

[0353] In a specific application scenario, the aggregation parameters include the aggregation reactive loop control parameters, which include the aggregation reactive droop coefficient, the aggregation reactive integral coefficient, the aggregation reactive power command value, and the aggregation reactive power actual output value. The aggregation reactive droop coefficient is expressed as the following formula:

[0354] ,

[0355] in, represents the aggregate reactive power droop coefficient, It represents the reactive power droop coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0356] The aggregate reactive integral coefficient is expressed as the following formula:

[0357] ,

[0358] in, Represents the aggregate reactive power integral coefficient, It represents the reactive integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0359] The aggregate reactive power command value is expressed as the following formula:

[0360] ,

[0361] in, Indicates the aggregated reactive power command value, Indicates the reactive power command value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0362] The actual output value of the aggregated reactive power is expressed as the following formula:

[0363] ,

[0364] in, Indicates the actual output value of aggregated reactive power. It represents the actual reactive power output value of the xth virtual synchronous generator in the virtual synchronous generator group.

[0365] In a specific application scenario, the aggregation parameters include aggregation voltage and current dual closed-loop control parameters, and the aggregation voltage and current dual closed-loop control parameters include aggregation current loop proportional coefficient, aggregation voltage loop proportional coefficient, and aggregation voltage loop integral coefficient. The aggregation current loop proportional coefficient is expressed as the following formula:

[0366] ,

[0367] in, represents the proportional coefficient of the aggregate current loop, Indicates the aggregate AC side filter inductance, It represents the current loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set. It represents the AC side filter inductance of the xth virtual synchronous generator in the virtual synchronous generator set.

[0368] The aggregate voltage loop proportional coefficient is expressed as the following formula:

[0369] ,

[0370] in, Represents the proportional coefficient of the aggregate voltage loop, It represents the voltage loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0371] The integral coefficient of the aggregation voltage loop is expressed as the following formula:

[0372] ,

[0373] in, represents the integral coefficient of the aggregate voltage loop, It represents the voltage loop integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

[0374] In a specific application scenario, the aggregation parameters include aggregation main circuit parameters, which include the inverse of the aggregated AC side filter inductance coefficient and the aggregated AC side filter capacitance coefficient. The inverse of the aggregated AC side filter inductance coefficient is expressed as the following formula:

[0375] ,

[0376] The aggregate AC side filter capacitance coefficient is expressed as the following formula:

[0377] ,

[0378] in, Indicates the aggregate AC side filter capacitance coefficient, It represents the AC side filter capacitance coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

[0379] The present application provides a quasi-coherent aggregation device for virtual synchronous generators, which first obtains the power angle change data of each virtual synchronous generator contained in the target power station within a preset time period after being subjected to a preset disturbance; secondly, any two virtual synchronous generators are selected one by one from all virtual synchronous generators as target virtual synchronous generator pairs, and the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair is calculated within a preset time window. If the maximum difference in the difference change data is less than or equal to a preset stability margin threshold, it is determined that the two virtual synchronous generators in the target virtual synchronous generator pair are coherent generators. Motor, the preset stability margin threshold is determined by using a pre-constructed stability margin threshold adjustment model, the stability margin threshold adjustment model is constructed based on the characteristic values ​​of each virtual synchronous generator contained in the target power station, and the preset time window is based on the inertia time constant of the synchronous generator, obtained by analogy according to a preset ratio; finally, according to the analog adjustment judgment results of each target virtual synchronous generator pair, all virtual synchronous generators are divided into multiple virtual synchronous generator groups, and each of the virtual synchronous generator groups is aggregated to obtain multiple aggregated virtual synchronous generators, and the aggregation parameters of each aggregated virtual synchronous generator are generated. Compared with the prior art, the embodiment of the present application constructs a stability margin threshold adjustment model in advance based on the characteristic values ​​of each virtual synchronous generator contained in the target power station to determine a preset stability margin threshold, and performs pairwise synchronization judgment on the virtual synchronous generators according to the threshold, and then divides all virtual synchronous generators into multiple virtual synchronous generator groups according to the pairwise synchronization judgment results, and aggregates them into aggregated virtual synchronous generators. Since the preset stability margin threshold used in the class synchronization judgment is determined based on the characteristic values ​​of each virtual synchronous generator contained in the target power station, it meets the actual environment and stability margin requirements of different power plants, improves the accuracy of the class synchronization judgment results, thereby improving the accuracy of the class synchronization aggregation results of the virtual synchronous generators, and makes the accuracy of the dynamic aggregation equivalence model higher.

[0380] According to one embodiment of the present application, a storage medium is provided, wherein the storage medium stores at least one executable instruction. The computer-executable instruction can execute the quasi-coherent aggregation method of virtual synchronous generators in any of the above method embodiments.

[0381] Based on this understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, USB flash drive, mobile hard disk, etc.), and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each implementation scenario of the present application.

[0382] Figure 5 A schematic diagram of the structure of a terminal provided according to an embodiment of the present application is shown. The specific embodiment of the present application does not limit the specific implementation of the terminal.

[0383] like Figure 5 As shown, the terminal may include: a processor (processor) 502 , a communications interface (Communications Interface) 504 , a memory (memory) 506 , and a communication bus 508 .

[0384] The processor 502 , the communication interface 504 , and the memory 506 communicate with each other via a communication bus 508 .

[0385] The communication interface 504 is used to communicate with other devices such as clients or other servers.

[0386] The processor 502 is configured to execute the program 510 , and specifically to execute the relevant steps in the embodiment of the aforementioned method for quasi-coherent aggregation of virtual synchronous generators.

[0387] Specifically, the program 510 may include program codes, which include computer operation instructions.

[0388] Processor 502 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in a computer device may be processors of the same type, such as one or more CPUs, or may be processors of different types, such as one or more CPUs and one or more ASICs.

[0389] The memory 506 is used to store the program 510. The memory 506 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage.

[0390] The program 510 may be specifically configured to enable the processor 502 to perform the following operations:

[0391] Obtaining power angle change data of each virtual synchronous generator included in the target power station within a preset time period after being subjected to a preset disturbance;

[0392] Selecting any two virtual synchronous generators from all virtual synchronous generators one by one as a target virtual synchronous generator pair, and calculating the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair within a preset time window, if the maximum difference in the difference change data is less than or equal to a preset stability margin threshold, then determining that the two virtual synchronous generators in the target virtual synchronous generator pair are synchronous generators, the preset stability margin threshold is determined by using a pre-constructed stability margin threshold adjustment model, the stability margin threshold adjustment model is constructed based on the characteristic values ​​of each virtual synchronous generator included in the target power station, and the preset time window is based on the inertia time constant of the synchronous generator, and is obtained by analogy according to a preset ratio;

[0393] According to the homology discrimination results of each target virtual synchronous generator pair, all virtual synchronous generators are divided into multiple virtual synchronous generator groups, and each of the virtual synchronous generator groups is aggregated to obtain multiple aggregated virtual synchronous generators, and aggregation parameters of each of the aggregated virtual synchronous generators are generated.

[0394] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages the hardware and software resources of the physical device used in the aforementioned virtual synchronous generator coherence aggregation method, supporting the execution of information processing programs and other software and / or programs. The network communication module is used to enable communication between components within the storage medium and with other hardware and software within the physical information processing device.

[0395] Each embodiment in this specification is described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. References to the same or similar parts between the various embodiments are sufficient. For system embodiments, since they largely correspond to method embodiments, their description is relatively simple. For relevant parts, references to the description of the method embodiments are sufficient.

[0396] The methods and systems of the present application may be implemented in many ways. For example, the methods and systems of the present application may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present application are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present application may also be implemented as programs recorded in a recording medium, which include machine-readable instructions for implementing the methods according to the present application. Therefore, the present application also covers recording media that store programs for executing the methods according to the present application.

[0397] Obviously, those skilled in the art should understand that the modules or steps of the present application described above can be implemented using a general-purpose computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices. Alternatively, they can be implemented using program code executable by the computing device, so that they can be stored in a storage device and executed by the computing device. In some cases, the steps shown or described can be performed in a different order than herein, or they can be made into separate integrated circuit modules, or multiple modules or steps can be made into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0398] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for quasi-coherence aggregation of virtual synchronous generators, characterized in that: include: Obtaining power angle change data of each virtual synchronous generator included in the target power station within a preset time period after being subjected to a preset disturbance; Selecting any two virtual synchronous generators from all virtual synchronous generators one by one as a target virtual synchronous generator pair, and calculating the difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair within a preset time window, if the maximum difference in the difference change data is less than or equal to a preset stability margin threshold, then determining that the two virtual synchronous generators in the target virtual synchronous generator pair are synchronous generators, the preset stability margin threshold is determined by using a pre-constructed stability margin threshold adjustment model, the stability margin threshold adjustment model is constructed based on the characteristic values ​​of each virtual synchronous generator included in the target power station, and the preset time window is based on the inertia time constant of the synchronous generator, and is obtained by analogy according to a preset ratio; According to the homogeneity discrimination results of each target virtual synchronous generator pair, all virtual synchronous generators are divided into a plurality of virtual synchronous generator groups, and each of the virtual synchronous generator groups is aggregated to obtain a plurality of aggregated virtual synchronous generators, and aggregation parameters of each of the aggregated virtual synchronous generators are generated; Before performing the similarity determination on the two virtual synchronous generators in the target virtual synchronous generator pair, the method further includes: Obtaining characteristic values ​​of each virtual synchronous generator included in the target power station; The minimum absolute value of the real part of each eigenvalue is determined as the dominant eigenvalue of the system. ， in, represents the dominant eigenvalue of the system, represents the number of virtual synchronous generators, Indicates the The characteristic values ​​of a virtual synchronous generator; Calculate the mean of the real parts of the eigenvalues, and determine the mean as the real part of the target eigenvalue. ， in, Expressed as the real part of the target eigenvalue; A stability margin threshold adjustment model is constructed based on the system dominant eigenvalue and the real part of the target eigenvalue. ， in, Indicates the preset stability margin threshold, represents the benchmark stability margin threshold; The obtaining of characteristic values ​​of each virtual synchronous generator included in the target power station includes: Construct the output active power expression of the virtual synchronous generator when injecting into the grid, ， in, represents the output active power of the virtual synchronous generator when it is injected into the grid, represents the voltage at the virtual synchronous generator terminal, Indicates the voltage of the grid, represents the equivalent reactance, represents the power angle of the virtual synchronous generator; According to the sine value of the power angle at the equilibrium point, the output active power expression is linearized to obtain the linearized output active power expression, and based on the linearized output active power expression and the rotor motion equation, the state matrix of the virtual synchronous generator is constructed. The state matrix is ​​expressed as the following formula: ， in, represents the state matrix of the virtual synchronous generator, represents the moment of inertia of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator, The sine of the power angle at the equilibrium point is , the output active power expression after linearization is, ， The rotor motion equation is expressed as the following formula, ， in, represents the angular velocity of the virtual synchronous generator, represents the rated angular velocity of the virtual synchronous generator, Indicates the active power command value of the virtual synchronous generator, Indicates the actual output value of active power of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator; A characteristic equation is constructed based on the state matrix, and the characteristic equation is expanded to obtain the expanded characteristic equation. ， in, represents the characteristic value of the virtual synchronous generator; Solving the expanded characteristic equation to obtain an eigenvalue expression of the virtual synchronous generator, and determining the eigenvalue of each virtual synchronous generator included in the target power station based on the eigenvalue expression, the eigenvalue expression is expressed as the following formula, 。 2. The method according to claim 1, characterized in that Before performing the similarity determination on the two virtual synchronous generators in the target virtual synchronous generator pair, the method further includes: Calculate the inertia time constant of the synchronous generator, ， in, represents the inertia time constant of the synchronous generator, represents the moment of inertia of the synchronous generator, represents the capacity of the synchronous generator, Indicates the rated speed of the synchronous generator; The preset time window is determined according to a preset ratio between the inertia time constant of the synchronous generator and the virtual rotational inertia time constant of the virtual synchronous generator.

3. The method according to claim 1, characterized in that The aggregate parameters include aggregate active power loop control parameters, which include aggregate active power command value, aggregate active power actual output value, aggregate damping coefficient, and aggregate rotational inertia. The aggregate active power command value is expressed as the following formula: ， in, Indicates the aggregated active power command value, Indicates the active power command value of the xth virtual synchronous generator in the virtual synchronous generator group. Indicates the number of virtual synchronous generators contained in the virtual synchronous generator set. The actual output value of the aggregated active power is expressed as the following formula: ， in, Indicates the actual output value of aggregated active power. Indicates the actual output value of active power of the xth virtual synchronous generator in the virtual synchronous generator group. The aggregate damping coefficient is expressed as the following formula: ， in, represents the aggregate damping coefficient, represents the damping coefficient of the xth virtual synchronous generator in the virtual synchronous generator set, The aggregate moment of inertia is expressed as the following formula: ， in, represents the aggregate moment of inertia, It represents the moment of inertia of the xth virtual synchronous generator in the virtual synchronous generator set.

4. The method according to claim 1, wherein The aggregation parameters include the aggregation reactive loop control parameters, which include the aggregation reactive droop coefficient, the aggregation reactive integral coefficient, the aggregation reactive power command value, and the aggregation reactive power actual output value. The aggregation reactive droop coefficient is expressed as the following formula: ， in, represents the aggregate reactive power droop coefficient, It represents the reactive power droop coefficient of the xth virtual synchronous generator in the virtual synchronous generator group. The aggregate reactive integral coefficient is expressed as the following formula: ， in, Represents the aggregate reactive power integral coefficient, It represents the reactive integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group. The aggregate reactive power command value is expressed as the following formula: ， in, Indicates the aggregated reactive power command value, Indicates the reactive power command value of the xth virtual synchronous generator in the virtual synchronous generator group. The actual output value of the aggregated reactive power is expressed as the following formula: ， in, Indicates the actual output value of aggregated reactive power. It represents the actual reactive power output value of the xth virtual synchronous generator in the virtual synchronous generator group.

5. The method according to claim 1, wherein The aggregation parameters include aggregation voltage and current dual closed-loop control parameters, which include aggregation current loop proportional coefficient, aggregation voltage loop proportional coefficient, and aggregation voltage loop integral coefficient. The aggregation current loop proportional coefficient is expressed as the following formula: ， in, represents the proportional coefficient of the aggregate current loop, Indicates the aggregate AC side filter inductance, It represents the current loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set. It represents the AC side filter inductance of the xth virtual synchronous generator in the virtual synchronous generator set. The aggregate voltage loop proportional coefficient is expressed as the following formula: ， in, Represents the proportional coefficient of the aggregate voltage loop, It represents the voltage loop proportional coefficient of the xth virtual synchronous generator in the virtual synchronous generator set. The integral coefficient of the aggregation voltage loop is expressed as the following formula: ， in, represents the integral coefficient of the aggregate voltage loop, It represents the voltage loop integral coefficient of the xth virtual synchronous generator in the virtual synchronous generator group.

6. The method according to claim 1, characterized in that The aggregation parameters include aggregation main circuit parameters, which include the inverse of the aggregation AC side filter inductance coefficient and the aggregation AC side filter capacitance coefficient. The inverse of the aggregation AC side filter inductance coefficient is expressed as the following formula: ， The aggregate AC side filter capacitance coefficient is expressed as the following formula: ， in, Indicates the aggregate AC side filter capacitance coefficient, It represents the AC side filter capacitance coefficient of the xth virtual synchronous generator in the virtual synchronous generator set.

7. A quasi-coherent aggregation device for a virtual synchronous generator, characterized in that: include: A data acquisition module is used to obtain power angle change data of each virtual synchronous generator included in the target power station within a preset time period after being subjected to a preset disturbance; a quasi-coherence discrimination module, configured to select any two virtual synchronous generators from all virtual synchronous generators one by one as a target virtual synchronous generator pair, and calculate, within a preset time window, difference change data between the power angle change data of the two virtual synchronous generators in the target virtual synchronous generator pair; if a maximum difference in the difference change data is less than or equal to a preset stability margin threshold, the two virtual synchronous generators in the target virtual synchronous generator pair are determined to be coherent generators, wherein the preset stability margin threshold is determined using a pre-constructed stability margin threshold adjustment model, which is constructed based on characteristic values ​​of each virtual synchronous generator included in the target power station; and the preset time window is obtained by analogy according to a preset ratio based on the inertia time constant of the synchronous generator; an aggregation module, configured to divide all virtual synchronous generators into a plurality of virtual synchronous generator groups according to the homogeneity discrimination results of each target virtual synchronous generator pair, aggregate each of the virtual synchronous generator groups to obtain a plurality of aggregated virtual synchronous generators, and generate aggregation parameters for each of the aggregated virtual synchronous generators; Before the homophonic discrimination module, the device further includes a stability margin threshold determination module, which is configured to: Obtaining characteristic values ​​of each virtual synchronous generator included in the target power station; The minimum absolute value of the real part of each eigenvalue is determined as the dominant eigenvalue of the system. ， in, represents the dominant eigenvalue of the system, represents the number of virtual synchronous generators, Indicates the The characteristic values ​​of a virtual synchronous generator; Calculate the mean of the real parts of the eigenvalues, and determine the mean as the real part of the target eigenvalue. ， in, Expressed as the real part of the target eigenvalue; A stability margin threshold adjustment model is constructed based on the system dominant eigenvalue and the real part of the target eigenvalue. ， in, Indicates the preset stability margin threshold, represents the benchmark stability margin threshold; The stability margin threshold determination module is further configured to: Construct the output active power expression of the virtual synchronous generator when injecting into the grid, ， in, represents the output active power of the virtual synchronous generator when it is injected into the grid, represents the voltage at the virtual synchronous generator terminal, Indicates the voltage of the grid, represents the equivalent reactance, represents the power angle of the virtual synchronous generator; According to the sine value of the power angle at the equilibrium point, the output active power expression is linearized to obtain the linearized output active power expression, and based on the linearized output active power expression and the rotor motion equation, the state matrix of the virtual synchronous generator is constructed. The state matrix is ​​expressed as the following formula: ， in, represents the state matrix of the virtual synchronous generator, represents the moment of inertia of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator, The sine of the power angle at the equilibrium point is , the output active power expression after linearization is, ， The rotor motion equation is expressed as the following formula, ， in, represents the angular velocity of the virtual synchronous generator, represents the rated angular velocity of the virtual synchronous generator, Indicates the active power command value of the virtual synchronous generator, Indicates the actual output value of active power of the virtual synchronous generator, represents the damping coefficient of the virtual synchronous generator; A characteristic equation is constructed based on the state matrix, and the characteristic equation is expanded to obtain the expanded characteristic equation. ， in, represents the characteristic value of the virtual synchronous generator; Solving the expanded characteristic equation to obtain an eigenvalue expression of the virtual synchronous generator, and determining the eigenvalue of each virtual synchronous generator included in the target power station based on the eigenvalue expression, the eigenvalue expression is expressed as the following formula, 。 8. A storage medium storing at least one executable instruction, characterized in that: The executable instructions enable the processor to execute operations corresponding to the quasi-coherent aggregation method for a virtual synchronous generator according to any one of claims 1 to 6.

9. A terminal comprising: A processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, wherein the executable instruction enables the processor to execute an operation corresponding to the quasi-coherent aggregation method of a virtual synchronous generator according to any one of claims 1 to 6.

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