Method and device for constructing stable operation domain of wind power system, electronic equipment and readable storage medium thereof

Abstract

The application belongs to the technical field of power system stability analysis, and relates to a method and device for constructing a wind power system operation stability domain, an electronic device and a readable storage medium thereof. First, a parameter space of the wind power system operation stability domain is constructed, impedance models of each device in the target system are constructed, a stability criterion based on aggregated impedance frequency characteristics is established, a stable operation point in the parameter space is determined, the initial point is searched, critical stable operation points corresponding to each output value in the single-machine output range are obtained, and finally, all the critical stable operation points are connected to form a stability domain boundary. The application establishes a stability criterion based on aggregated impedance frequency characteristics, which can quickly and accurately determine the stability of the sub / super-synchronous oscillation mode of the system under each operation parameter. The operation stability domain of the wind power system is constructed by a boundary search method, which has small calculation amount and low conservativeness, and can provide guidance for sub / super-synchronous oscillation prevention and control and safe and stable operation of the system.

Description

Technical Field

[0001] This application belongs to the field of power system stability analysis technology, and relates to the construction method, device, electronic equipment and readable storage medium of the operating stability domain of wind power system. Background Technology

[0002] In recent years, with the increasing penetration rate of wind power, the power system has experienced several new types of subsynchronous / supersynchronous oscillations involving wind power, such as the subsynchronous / supersynchronous oscillations that occurred at the Guyuan Wind Power Base in North China and the Hami Wind Farm in Xinjiang. These incidents have reduced power quality, compromised equipment safety, and jeopardized the reliable operation of the power grid. To analyze the oscillation stability of wind power systems under different operating parameters and to measure the system's stability margin, it is necessary to construct the system's operating stability domain, providing crucial information for the prevention and control of subsynchronous / supersynchronous oscillations.

[0003] Existing stability domains for wind power systems aimed at controlling subsynchronous / supersynchronous oscillations are mostly parametric stability domains, which consider the impact of system structural parameters and controller parameters on the stability of subsynchronous / supersynchronous oscillations. Since the stability of subsynchronous / supersynchronous oscillations in wind power systems is closely related to the system's operating point, existing parametric stability domains are insufficient to provide guidance for the safe and stable operation of the system. Furthermore, considering the typically complex nature of wind power systems, methods that derive all system eigenvalues ​​based on a time-domain state-space model and then determine oscillation stability based on the sign of the real parts of these eigenvalues ​​involve large computational loads and may even suffer from the curse of dimensionality. Summary of the Invention

[0004] In view of this, this disclosure proposes a method, apparatus, electronic equipment and readable storage medium for constructing a stable operating domain of a wind power system, in order to solve the problems in the related technology.

[0005] According to the first aspect of this disclosure, a method for constructing the operating stability domain of a wind power system is proposed, including:

[0006] Construct the parameter space of the wind power system's operational stability domain;

[0007] Establish a full-condition impedance model of the wind turbine generator and the impedance of other equipment in the wind power system.

[0008] Establish a stability criterion based on the frequency characteristics of polymer impedance;

[0009] Find the critical stable operating point in the parameter space;

[0010] Search for the critical stable operating point;

[0011] Connecting all critically stable operating points forms the boundary of the stability region.

[0012] Optionally, the construction of the wind power system's operational stability domain parameter space includes:

[0013] The output of a single wind turbine in the wind power system and the number of wind turbines connected to the grid in the wind farm are used as parameters to construct the operational stability domain.

[0014] Set the range of values ​​for the operating parameters of the wind power system, and denote the output range of a single wind turbine in the wind power system as [p]. low ,p high The range of the number of grid-connected wind turbines is denoted as [n]. low ,n high ].

[0015] Optionally, establish a full-condition impedance model for the wind turbine generator and the impedance of other equipment in the wind power system, including:

[0016] Establish a full-condition impedance model for the wind turbine, and define the impedance Z of the wind turbine. WTG (s) can be expressed as a function of the operating point:

[0017] The impedance of other devices is calculated using mechanistic derivation or external characteristic identification methods.

[0018] Optionally, the process of establishing a stability criterion based on the frequency characteristics of the polymer impedance is as follows:

[0019] Calculate the impedance of a wind farm in a wind power system under any operating parameter (p,n);

[0020] Establish the impedance network of the wind power system under the current operating parameters, and form the nodal admittance matrix of the impedance network;

[0021] The impedance network is simplified into a aggregated impedance to obtain the frequency characteristics of the aggregated impedance.

[0022] The stability of the subsynchronous / supersynchronous oscillation mode of the wind power system is determined based on the frequency characteristic curve of the polymer impedance.

[0023] Optionally, finding the critical stable operating point in the parameter space includes:

[0024] Set the search step size for the number of grid-connected wind turbines to Δn;

[0025] Setting the output of a single wind turbine and the number of grid-connected wind turbines to their minimum values ​​respectively, as a stable operating point, the active power output of a single wind turbine in the wind power system is p = p low The number of grid-connected wind turbines n = n low ;

[0026] Keeping p constant, the number of grid-connected wind turbines n is gradually increased with a step size Δn. Based on the stability criterion based on the frequency characteristics of aggregate impedance, the stability of the subsynchronous / supersynchronous oscillation mode under each operating parameter is judged. If the subsynchronous / supersynchronous oscillation mode in the wind power system changes abruptly from stable to unstable, the number of grid-connected wind turbines before the change is recorded as N; if the subsynchronous / supersynchronous oscillation mode in the wind power system remains stable, then N = n high (p,N) is the critical stable operating point.

[0027] Optionally, the search for the critical stable operating point includes:

[0028] Set the output search step size for a single wind turbine unit to Δp;

[0029] Let p = P t +△p, n=N t ;

[0030] Based on the stability criterion based on the frequency characteristics of aggregate impedance, the stability of the subsynchronous / supersynchronous oscillation mode of the target wind power system at operating parameters (p,n) is determined:

[0031] If stable, keep p constant and gradually increase the number of grid-connected wind turbines n with a step size Δn. Further, based on the stability criterion based on the polymer impedance frequency characteristics, determine the stability of the subsynchronous / supersynchronous oscillation mode under each operating parameter. If the subsynchronous / supersynchronous oscillation mode abruptly changes from stable to unstable, denoted as N before the abrupt change, (p, N) is the critical stable operating point. Let t = t + 1, P t =p,N t =N, if the subsynchronous / supersynchronous oscillation mode remains stable, then let N = n high (p, N) is the critical stable operating point. Let t = t + 1, P t =p,N t =N;

[0032] If unstable, keep p constant and gradually decrease the number of grid-connected wind turbines n with a step size Δn. Based on the stability criterion based on the polymer impedance frequency characteristics, determine the stability of the subsynchronous / supersynchronous oscillation mode under each operating parameter. If the subsynchronous / supersynchronous oscillation mode abruptly changes from unstable to stable, denoted as N, then (p, N) is the critical stable operating point. Let t = t + 1, P... t =p,N t =N, if the subsynchronous / supersynchronous oscillation mode remains unstable, repeat the above process until P. t =p high .

[0033] According to a second aspect of this disclosure, an apparatus for constructing a stable operating region for a wind power system is provided, comprising:

[0034] Establish a parameter space module to construct the parameter space of the wind power system's operating stability domain;

[0035] The impedance calculation module is used to establish the full-condition impedance model of wind turbines and the impedance of other equipment in the wind power system.

[0036] Establish a criterion module to create a stable criterion based on the frequency characteristics of aggregate impedance;

[0037] The search module is used to find the critical stable operating point from a stable operating point in the parameter space;

[0038] The search module is used to search for critical stable operating points;

[0039] The connection module is used to connect all critical stable operating points to form the boundary of the stability domain.

[0040] Optionally, the criterion establishment module includes:

[0041] The first calculation unit is used to calculate the impedance of the wind farm in the wind power system under any operating parameter (p,n);

[0042] Impedance network forming unit is used to establish the impedance network of the wind power system under the current operating parameters and to form the nodal admittance matrix of the impedance network;

[0043] The second calculation unit is used to simplify the impedance network into a aggregated impedance and obtain the frequency characteristics of the aggregated impedance.

[0044] The judgment unit is used to judge the stability of the subsynchronous / supersynchronous oscillation mode of the wind power system based on the frequency characteristic curve of the aggregate impedance.

[0045] According to a third aspect of this disclosure, an electronic device is proposed, comprising:

[0046] Memory is used to store executable instructions for a computer;

[0047] Processor, the processor being configured to execute:

[0048] Construct the parameter space of the wind power system's operational stability domain;

[0049] Establish a full-condition impedance model of the wind turbine generator and the impedance of other equipment in the wind power system.

[0050] Establish a stability criterion based on the frequency characteristics of polymer impedance;

[0051] Find the critical stable operating point in the parameter space;

[0052] Search for the critical stable operating point;

[0053] Connecting all critically stable operating points forms the boundary of the stability region.

[0054] According to a fourth aspect of this disclosure, a computer-readable storage medium is provided having a computer program stored thereon, the computer program being configured to cause the computer to perform:

[0055] Construct the parameter space of the wind power system's operational stability domain;

[0056] Establish a full-condition impedance model of the wind turbine generator and the impedance of other equipment in the wind power system.

[0057] Establish a stability criterion based on the frequency characteristics of polymer impedance;

[0058] Find the critical stable operating point in the parameter space;

[0059] Search for the critical stable operating point;

[0060] Connecting all critically stable operating points forms the boundary of the stability region.

[0061] According to embodiments of this disclosure, the key operating parameters affecting the stability of wind power sub / supersynchronous oscillations—namely, the output of a single wind turbine and the number of grid-connected wind turbines—are used as two-dimensional parameters to construct the stable operating domain of the wind power system. A parameter space for the stable operating domain of the wind power system is constructed, and impedance models of each device in the target system are built. A stability criterion based on the frequency characteristics of aggregated impedance is established, and a stable operating point in the parameter space is determined. Using this point as the initial point, critical stable operating points are first searched along the directions of increasing and decreasing number of grid-connected wind turbines, and then along the directions of increasing and decreasing single-unit output, until the critical stable operating points corresponding to each output value within the studied single-unit output range are obtained. Finally, all critical stable operating points are connected to form the boundary of the stable domain. The area inside the boundary is the stable operating domain of the wind power system for sub / supersynchronous oscillation control, thus comprehensively reflecting the impact of operating points on the system's sub / supersynchronous oscillations. This application establishes a stability criterion based on the frequency characteristics of aggregated impedance, which can quickly and accurately determine the stability of the system's sub / supersynchronous oscillation mode under various operating parameters. The operational stability domain of the wind power system was constructed using a boundary search method. This method has low computational cost and low conservatism, and can provide guidance for the prevention and control of subsynchronous / supersynchronous oscillations and the safe and stable operation of the system.

[0062] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0063] Figure 1 This is a schematic flow diagram illustrating a method for constructing a stable operating domain of a wind power system according to an embodiment of the present disclosure.

[0064] Figure 2 This is a schematic flow diagram of an apparatus for constructing a stable operating domain for a wind power system, according to an embodiment of the present disclosure.

[0065] Figure 3 This is a schematic flow diagram of a criterion module in a device for constructing a stable operating domain of a wind power system, according to an embodiment of the present disclosure. Detailed Implementation

[0066] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0067] Figure 1 This is a schematic flow diagram illustrating a method for constructing a stable operating domain for a wind power system according to an embodiment of this disclosure. The method for constructing a stable operating domain for a wind power system according to this embodiment can be applied to user equipment, such as mobile phones, tablets, etc.

[0068] like Figure 1 As shown, the method for constructing the stable operating domain of a wind power system includes...

[0069] In step 1, the parameter space of the wind power system's operating stability domain is constructed.

[0070] In one embodiment, constructing the wind power system's operational stability domain parameter space includes:

[0071] (1) The output of a single wind turbine in the wind power system and the number of wind turbines connected to the grid in the wind farm are used as parameters to construct the stable operating domain.

[0072] (2) Set the range of values ​​for the operating parameters of the wind power system, and denote the output range of a single wind turbine in the wind power system as [p low ,p high The range of the number of grid-connected wind turbines is denoted as [n]. low ,n high ].

[0073] In step 2, a full-condition impedance model of the wind turbine and the impedance of other equipment in the wind power system are established.

[0074] In one embodiment, establishing a full-condition impedance model of the wind turbine generator and the impedance of other equipment in the wind power system includes:

[0075] (1) Establish a full-condition impedance model for the wind turbine, and define the impedance Z of the wind turbine. WTG (s) can be expressed as a function of the operating point:

[0076] Z WTG (s)=F(s,U1,I1)

[0077] Where U1 is the power frequency voltage phasor of the wind turbine, I1 is the power frequency current phasor of the wind turbine, and s is the Laplace operator.

[0078] (2) Calculate the impedance of other equipment using mechanism derivation or external characteristic identification methods. Other equipment includes turbine units, lines, transformers, etc.

[0079] In step 3, a stability criterion based on the frequency characteristics of polymer impedance is established.

[0080] In one embodiment, a stability criterion based on the frequency characteristics of the aggregate impedance is established, and the specific process is as follows:

[0081] (1) Calculate the impedance of the wind farm in the wind power system under any operating parameters (p,n), including the following steps:

[0082] (1-1) Perform power flow calculations on the wind power system. Set the wind farm node in the wind power system as PQ node (i.e., active and reactive node). The output active power of the wind farm is P, P = p * n, where p is the output active power of a single wind turbine and n is the number of grid-connected wind turbines.

[0083] (1-2) Based on the power flow calculation results in step (1-1), calculate the power frequency voltage phasor U1 and power frequency current phasor I1 at the wind turbine port respectively, and substitute U1 and I1 into the full-condition impedance model of the wind turbine to obtain the impedance of the wind turbine under the current operating parameters.

[0084] (1-3) Divide the impedance of a single wind turbine unit in step (1-2) by the number of grid-connected wind turbines n to obtain the impedance of the wind farm under the current operating parameters.

[0085] (2) Establish the impedance network of the wind power system under the current operating parameters and form the nodal admittance matrix of the impedance network, including the following steps:

[0086] (2-1) Connect the impedances of each device in step (1-3) according to the topology of the wind power system to form the impedance network of the wind power system.

[0087] (2-2) The nodal admittance matrix Y(s) of the impedance network is established as follows:

[0088] Y(s) = AY D (s)A T

[0089] Where A is the node-branch correlation matrix of the wind power system, and Y D(s) is the branch admittance matrix, which is a diagonal matrix, and the diagonal elements in the diagonal matrix are the admittances of each branch device;

[0090] (3) Simplify the impedance network in step (2) into a aggregated impedance and obtain the frequency characteristics of the aggregated impedance, including the following steps:

[0091] (3-1) Select any node #i from the impedance network as the aggregation port of the impedance network, and obtain the aggregated impedance Z of the target wind power system according to the node admittance matrix in step (2-2). ∑ (s):

[0092]

[0093] Among them, Y -1 Y is the inverse matrix of the impedance network node admittance matrix from step (2-2). -1 (i,i) represents Y -1 The element in the i-th row and i-th column;

[0094] (3-2) Define the frequency range ω of the sub / supersynchronous oscillation mode of interest, ω∈[ω low ,ω high Substitute s = jω into Z ∑ (s), to obtain Z ∑ The numerical solution of (s), i.e., the frequency characteristic of the polymer impedance, where Z ∑ (s) represents the aggregation impedance, s is the Laplace operator, and j is the imaginary unit;

[0095] (3-3) The polymer impedance frequency characteristic Z ∑ The real and imaginary parts of (jω) are called the equivalent resistance and equivalent reactance of the aggregate impedance, respectively. Based on the frequency characteristics of the aggregate impedance in step (3-2), draw the equivalent resistance-frequency curve and equivalent reactance-frequency curve of the aggregate impedance.

[0096] (4) The stability of the subsynchronous / supersynchronous oscillation mode of the wind power system is judged based on the frequency characteristic curve of the aggregate impedance:

[0097] (4-1) When there exists a frequency ω on the equivalent reactance-frequency curve of the polymer impedance r If the zero-crossing point is reached, then it is determined that the target wind power system has a frequency of ω. r The stability of the subsynchronous / supersynchronous oscillation mode is further judged based on the sign of the product of the slope of the equivalent resistance and the equivalent reactance at the zero crossing point. If the product is greater than zero, the oscillation mode is determined to be stable; if the product is less than or equal to zero, the oscillation mode is determined to be unstable.

[0098] (4-2) When there exists a frequency ω on the equivalent resistance-frequency curve of the polymer impedancer If the zero-crossing point is reached, then it is determined that the target wind power system has a frequency of ω. r The stability of the oscillation mode is further judged based on the sign of the product of the slope of the equivalent reactance and the equivalent resistance at the zero crossing point. If the product is greater than zero, the oscillation mode is determined to be unstable; if the product is less than or equal to zero, the oscillation mode is determined to be unstable.

[0099] In the above steps of the embodiments of this disclosure, a stability criterion based on the frequency characteristics of aggregate impedance is established, which can be used to determine the stability of the subsynchronous / supersynchronous oscillation mode of the wind power system under any operating parameter. This avoids the large amount of calculations generated by directly solving the zero point of aggregate impedance and can quickly and accurately locate the subsynchronous / supersynchronous oscillation mode.

[0100] In step 4, the critical stable operating point is searched in the parameter space as the starting point for searching the boundary of the stability region.

[0101] In one embodiment, finding a critically stable operating point in the parameter space as the starting point for searching the boundary of the stability region includes:

[0102] (1) Set the search step size for the number of grid-connected wind turbines to Δn;

[0103] (2) Set the output of a single wind turbine and the number of grid-connected wind turbines to their minimum values ​​respectively, as a stable operating point. At this point, the active power output of a single wind turbine in the wind power system is p = p low Number of grid-connected wind turbines n = n low ;

[0104] (3) Keeping p constant, gradually increase the number of grid-connected wind turbines n with a step size Δn. Based on the stability criterion based on the frequency characteristics of aggregate impedance, judge the stability of the subsynchronous / supersynchronous oscillation mode under each operating parameter. If the subsynchronous / supersynchronous oscillation mode in the wind power system changes abruptly from stable to unstable, then record the number of grid-connected wind turbines before the change as N; if the subsynchronous / supersynchronous oscillation mode in the wind power system remains stable (if there is no abrupt change from stable to unstable mode), then let N = n high (p,N) is the critical stable operating point; that is, the first stability domain boundary point of the wind power system. Let t=1, P t =p,N t =N.

[0105] In step 5, the critical stable operating point is searched.

[0106] In one embodiment, the critical stable operating point is searched; that is, in the parameter space, with (P) 1 N 1Starting from a point, the search continues along the direction of increasing output of a single wind turbine unit until the critical stable operating point is obtained where the output of a single wind turbine unit reaches the set maximum value. This includes:

[0107] (1) Set the output search step size of a single wind turbine to Δp;

[0108] (2) Let p = P t +△p, n=N t ;

[0109] (3) Based on the stability criterion based on the frequency characteristics of aggregate impedance, the stability of the subsynchronous / supersynchronous oscillation mode of the target wind power system at operating parameters (p,n) is judged:

[0110] If stable, keep p constant and gradually increase the number of grid-connected wind turbines n with a step size Δn. Further, based on the stability criterion based on the polymer impedance frequency characteristics, determine the stability of the subsynchronous / supersynchronous oscillation mode under each operating parameter. If the subsynchronous / supersynchronous oscillation mode abruptly changes from stable to unstable, denoted as N before the abrupt change, (p, N) is the critical stable operating point. Let t = t + 1, P t =p,N t =N, if the subsynchronous / supersynchronous oscillation mode remains stable, then let N = n high (p, N) is the critical stable operating point. Let t = t + 1, P t =p,N t =N;

[0111] If unstable, keep p constant and gradually decrease the number of grid-connected wind turbines n with a step size Δn. Based on the stability criterion based on the polymer impedance frequency characteristics, determine the stability of the subsynchronous / supersynchronous oscillation mode under each operating parameter. If the subsynchronous / supersynchronous oscillation mode abruptly changes from unstable to stable, denoted as N, then (p, N) is the critical stable operating point. Let t = t + 1, P... t =p,N t =N, if the sub / supersynchronous oscillation mode remains unstable, then return to step (2);

[0112] (4) Repeat steps (2)-(3) until P. t =p high .

[0113] In the embodiments of this disclosure, the proximity of adjacent boundary points is fully utilized to search for the next boundary point near the previous boundary point, thus greatly reducing the number of searches. While ensuring the accuracy of the stability domain search, the search efficiency of the wind power system's operating stability domain is improved.

[0114] In step 6, all critical stable operating points are connected to form the boundary of the stability domain, and the area inside the boundary is the target wind power system's stable operating domain.

[0115] Corresponding to the embodiments of the above-described method for constructing the stable operating domain of a wind power system, this disclosure also proposes embodiments of an apparatus for constructing the stable operating domain of a wind power system.

[0116] Figure 2 This is a schematic block diagram of a device for constructing a stable operating domain for a wind power system according to an embodiment of this disclosure, including:

[0117] Establish a parameter space module to construct the parameter space of the wind power system's operating stability domain;

[0118] The impedance calculation module is used to establish the full-condition impedance model of wind turbines and the impedance of other equipment in the wind power system.

[0119] Establish a criterion module to create a stable criterion based on the frequency characteristics of aggregate impedance;

[0120] The search module is used to find the critical stable operating point from a stable operating point in the parameter space;

[0121] The search module is used to search for critical stable operating points;

[0122] The connection module is used to connect all critical stable operating points to form the boundary of the stability domain.

[0123] Figure 3 This is a schematic block diagram illustrating a criterion establishment module according to an embodiment of the present disclosure, such as... Figure 3 As shown, in Figure 2 Based on the illustrated embodiment, the criterion module includes:

[0124] The first calculation unit is used to calculate the impedance of the wind farm in the wind power system under any operating parameter (p,n);

[0125] Impedance network forming unit is used to establish the impedance network of the wind power system under the current operating parameters and to form the nodal admittance matrix of the impedance network;

[0126] The second calculation unit is used to simplify the impedance network into a aggregated impedance and obtain the frequency characteristics of the aggregated impedance.

[0127] The judgment unit is used to judge the stability of the subsynchronous / supersynchronous oscillation mode of the wind power system based on the frequency characteristic curve of the aggregate impedance.

[0128] Embodiments of this disclosure also propose an electronic device, including:

[0129] Memory is used to store executable instructions for a computer;

[0130] Processor, the processor being configured to execute:

[0131] Construct the parameter space of the wind power system's operational stability domain;

[0132] Establish a full-condition impedance model of the wind turbine generator and the impedance of other equipment in the wind power system.

[0133] Establish a stability criterion based on the frequency characteristics of polymer impedance;

[0134] Find the critical stable operating point in the parameter space;

[0135] Search for the critical stable operating point;

[0136] Connecting all critically stable operating points forms the boundary of the stability region.

[0137] One embodiment of this disclosure provides a computer-readable storage medium on which a computer program is stored, the computer program being used to cause the computer to execute:

[0138] Construct the parameter space of the wind power system's operational stability domain;

[0139] Establish a full-condition impedance model of the wind turbine generator and the impedance of other equipment in the wind power system.

[0140] Establish a stability criterion based on the frequency characteristics of polymer impedance;

[0141] Find the critical stable operating point in the parameter space;

[0142] Search for the critical stable operating point;

[0143] Connecting all critically stable operating points forms the boundary of the stability region.

[0144] It should be noted that, in the embodiments of this disclosure, the processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor. The memory can be used to store the computer program and / or modules. The processor implements various functions of the automotive parts image dataset creation device by running or executing the computer program and / or modules stored in the memory, and by calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created based on the use of the mobile phone (such as audio data, phonebook, etc.), etc. Furthermore, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart memory cards (SMC), secure digital cards (SD), flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices. Modules / units of the wind power system's stable operating domain construction device, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium may include any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0145] The above description represents the preferred embodiments of this disclosure. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered to be within the scope of protection of this invention.

Claims

1. A method for constructing a stable operating domain for a wind power system, characterized in that, include: Construct the parameter space of the wind power system's operational stability domain; Establish a full-condition impedance model of the wind turbine generator and the impedance of other equipment in the wind power system. A stability criterion based on the frequency characteristics of aggregated impedance is established. The specific process for establishing this criterion is as follows: Calculate the stability criterion of the wind farm in the wind power system under any operating parameter... p , n The impedance under the current operating parameters is established; an impedance network of the wind power system is established, and the nodal admittance matrix of the impedance network is formed; the impedance network is simplified into a aggregate impedance, and the frequency characteristic curve of the aggregate impedance is obtained; based on the frequency characteristic curve of the aggregate impedance, the stability of the subsynchronous / supersynchronous oscillation mode of the wind power system is judged, wherein the construction of the wind power system operation stability domain parameter space includes: using the output of a single wind turbine in the wind power system and the number of grid-connected wind turbines in the wind farm as parameters for constructing the operation stability domain; setting the value range of the wind power system operation parameters, and denoting the output range of a single wind turbine in the wind power system as [ p low , p high The range of grid-connected wind turbines is denoted as []. n low , n high ]; Find the critical stable operating point in the parameter space; Search for the critical stable operating point; Connecting all critically stable operating points forms the boundary of the stability region.

2. The method for constructing the stable operating domain of a wind power system according to claim 1, characterized in that, The establishment of the full-condition impedance model of the wind turbine in the wind power system and the impedance of other equipment includes: Establish a full-condition impedance model for the wind turbine, and measure the impedance of the wind turbine. Functions expressed as operating points: The impedance of other devices is calculated using mechanistic derivation or external characteristic identification methods.

3. The method for constructing the stable operating domain of a wind power system according to claim 1, characterized in that, The process of finding the critical stable operating point in the parameter space includes: The search step size for the number of grid-connected wind turbines is set to △ n ; Setting the output of a single wind turbine and the number of grid-connected wind turbines to their minimum values ​​respectively, we can define a stable operating point. At this point, the active power output of a single wind turbine in the wind power system is... p = p low Number of grid-connected wind turbines n = n low ; Keep p Unchanged, with step size △ n Gradually increase the number of grid-connected wind turbines n Based on the stability criterion based on the frequency characteristics of aggregate impedance, the stability of the subsynchronous / supersynchronous oscillation mode under various operating parameters is judged. If the subsynchronous / supersynchronous oscillation mode in the wind power system changes abruptly from stable to unstable, the number of grid-connected wind turbines before the abrupt change is recorded as follows: N If the subsynchronous / supersynchronous oscillation mode in the wind power system remains stable, then let N = n high ;( p , N This is the critical stable operating point.

4. The method for constructing the stable operating domain of a wind power system according to claim 1, characterized in that, Search for critical stable operating points, including: 6-1 Set the output search step size of a single wind turbine to Δ p ; 6-2 Order p = P t +△ p , n = N t ; 6-3 Based on the stability criterion based on the frequency characteristics of aggregate impedance, the target wind power system is subjected to the following operating parameters ( p , n The stability of the subsynchronous / supersynchronous oscillation mode at that time is judged: If stable, then maintain. p Unchanged, with step size △ n Gradually increase the number of grid-connected wind turbines n Furthermore, based on the stability criterion based on the polymer impedance frequency characteristics, the stability of the subsynchronous / supersynchronous oscillation mode under each operating parameter is determined. If the subsynchronous / supersynchronous oscillation mode abruptly changes from stable to unstable, the number of grid-connected wind turbines before the abrupt change is recorded as follows: N , ( p , N That is, the critical stable operating point, let t = t +1, P t = p , N t = N If the subsynchronous / supersynchronous oscillation mode remains stable, then let N = n high ;( p , N That is, the critical stable operating point, let t = t +1, P t = p , N t = N ; If unstable, then maintain p Unchanged, with step size △ n Gradually reduce the number of grid-connected wind turbines n Based on the stability criterion based on the polymer impedance frequency characteristics, the stability of the subsynchronous / supersynchronous oscillation mode under various operating parameters is determined. If the subsynchronous / supersynchronous oscillation mode abruptly changes from unstable to stable, the number of grid-connected wind turbines at this time is recorded as follows: N , ( p , N That is, the critical stable operating point, let t = t +1, P t = p , N t = N If the subsynchronous / supersynchronous oscillation mode remains unstable, return to step (6-2). 6-4 Repeat steps 6-2 through 6-3 until... P t = p high .

5. A device for constructing a stable operating region for a wind power system, characterized in that, include: Establish a parameter space module to construct the parameter space of the wind power system's operating stability domain; The impedance calculation module is used to establish the full-condition impedance model of wind turbines and the impedance of other equipment in the wind power system. A criterion module is established to create a stability criterion based on the frequency characteristics of aggregated impedance. The specific process for establishing this stability criterion is as follows: Calculate the stability criterion of the wind farm in the wind power system under any operating parameter... p , n The impedance under the current operating parameters is established; an impedance network of the wind power system is established, and the node admittance matrix of the impedance network is formed; the impedance network is simplified into aggregate impedance, and the frequency characteristic curve of the aggregate impedance is obtained; the stability of the subsynchronous / supersynchronous oscillation mode of the wind power system is judged according to the frequency characteristic curve of the aggregate impedance, wherein the construction of the wind power system operation stability domain parameter space includes: (1) taking the output of a single wind turbine in the wind power system and the number of wind turbines connected to the grid in the wind farm as parameters for constructing the operation stability domain; (2) setting the value range of the wind power system operation parameters, and denoting the output range of a single wind turbine in the wind power system as [ p low , p high The range of grid-connected wind turbines is denoted as []. n low , n high ]; The search module is used to find the critical stable operating point from a stable operating point in the parameter space; The search module is used to search for critical stable operating points; The connection module is used to connect all critical stable operating points to form the boundary of the stability domain.

6. The apparatus for constructing a stable operating region for a wind power system according to claim 5, characterized in that, The criterion establishment module includes: The first calculation unit is used to calculate the impedance of the wind farm in the wind power system under any operating parameters. Impedance network forming unit is used to establish the impedance network of the wind power system under the current operating parameters and to form the nodal admittance matrix of the impedance network; The second calculation unit is used to simplify the impedance network into a aggregated impedance and obtain the frequency characteristics of the aggregated impedance. The judgment unit is used to judge the stability of the subsynchronous / supersynchronous oscillation mode of the wind power system based on the frequency characteristic curve of the aggregate impedance.

7. An electronic device, characterized in that, include: Memory is used to store executable instructions for a computer; A processor configured to execute the method for constructing a stable operating domain for a wind power system according to any one of claims 1-4.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program for causing the computer to execute the method for constructing the operating stability domain of the wind power system according to any one of claims 1-4.

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