Power grid transient stability checking method and device considering wind power plant output mode

Abstract

The invention discloses a power grid transient stability checking method and device considering a wind power plant output mode. The method comprises the following steps: constructing an equivalent model of a wind power plant in various different output modes; performing fault simulation on the wind power plant by using each equivalent model to obtain a power angle curve of the observation unit under each equivalent model; determining the maximum power angle difference value of each power angle curve, and carrying out descending sorting on the maximum power angle difference value to obtain a first sorting result; determining the equivalent model corresponding to the maximum power angle difference value as a target equivalent model according to the first sorting result; and performing power grid transient stability check on the wind power plant by using the target equivalent model to obtain a check result, so that the accuracy of the check result reaches an accuracy threshold. According to the method, the technical problem that the checking result is inaccurate due to the fact that the influence of the operation mode of the wind power plant on the transient stability of the power grid is not fully considered when the transient stability checking is carried out on the power grid by using the wind power plant equivalent model through a traditional method in the related technology is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power system modeling, and in particular to a method and device for verifying transient stability of a power grid taking into account wind farm output modes. Background Art

[0002] The commonly used modeling method for wind farms is the aggregation method, which is to equalize the wind turbines in the wind farm into one or several units, and the equivalent unit model retains or basically retains the model structure of the original unit. The aggregation method generally assumes that the active output of wind turbines in the wind farm is basically the same. Due to the influence of factors such as the distribution characteristics of the wind farm, the active output of wind turbines in the wind farm may vary greatly, resulting in certain modeling errors. On the other hand, in the calculation of the operation mode of the power grid, it is necessary to consider the impact of various operating conditions of wind turbines in the wind farm on the transient stability of the power grid, while the aggregation method does not consider the actual needs of the calculation of the operation mode of the power grid.

[0003] In view of the problem that the traditional method in the above-mentioned related technologies uses the equivalent model of wind farms to perform transient stability verification on the power grid without fully considering the impact of the operation mode of the wind farm on the transient stability of the power grid, resulting in inaccurate verification results, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present invention provide a method and device for checking transient stability of a power grid taking into account the output mode of a wind farm, so as to at least solve the technical problem in the related art that when using the traditional method to check the transient stability of the power grid using the equivalent model of a wind farm, the influence of the operation mode of the wind farm on the transient stability of the power grid is not fully considered, resulting in inaccurate verification results.

[0005] According to one aspect of an embodiment of the present invention, there is provided a method for checking transient stability of a power grid taking into account the output mode of a wind farm, comprising: constructing equivalent models of a wind farm under a plurality of different output modes to obtain a plurality of equivalent models, wherein the wind farm is a power plant in a power grid; using each of the equivalent models to perform fault simulation on the wind farm to obtain a power angle curve of an observation unit under each of the equivalent models, wherein the observation unit is used to record a power angle variation curve when the wind farm is subjected to fault simulation using the equivalent model; determining a maximum power angle difference of each of the power angle curves to obtain a plurality of maximum power angle curves. Angle difference, wherein the maximum power angle difference is the difference between the original power angle value of the observed unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observed unit before the equivalent model is used to perform fault simulation on the wind farm; sorting the multiple maximum power angle differences in descending order to obtain a first sorting result; determining the equivalent model corresponding to the largest maximum power angle difference as the target equivalent model according to the first sorting result; and performing grid transient stability verification on the wind farm using the target equivalent model to obtain a verification result so that the accuracy of the verification result reaches an accuracy threshold.

[0006] Optionally, constructing equivalent models of a wind farm under a plurality of different output modes to obtain a plurality of the equivalent models includes: determining a plurality of wind turbines operating in the wind farm under each of the output modes; clustering the plurality of wind turbines corresponding to each of the output modes to obtain a wind turbine class corresponding to each of the output modes; performing equivalent processing and simplification processing on the wind turbine class corresponding to each of the output modes to obtain model parameters corresponding to each of the output modes; constructing the equivalent models corresponding to each of the output modes according to the model parameters corresponding to each of the output modes to obtain a plurality of the equivalent models.

[0007] Optionally, the output mode includes: a large startup and large output mode, a large startup and small output mode, a small startup and large output mode, and a small startup and small output mode. Determining a plurality of wind turbines operating in the wind farm under each of the output modes includes: when the output mode is the large startup and large output mode, determining that all the wind turbines in the wind farm are connected to the grid and operate at a rated active power value; when the output mode is the large startup and small output mode, determining that all the wind turbines in the wind farm are connected to the grid and operate at a first active power value. value and connected to the grid, wherein the first active power value is a first predetermined multiple of the rated active power value; when the output mode is the small startup and large output mode, it is determined that a predetermined number of the wind turbines in the wind farm are all connected to the grid and run at the rated active power value, wherein the predetermined number is a second predetermined multiple of the total number of all the wind turbines; when the output mode is the small startup and small output mode, it is determined that the predetermined number of the wind turbines in the wind farm are all connected to the grid and run at the first active power value.

[0008] Optionally, clustering is performed on multiple wind turbines corresponding to each of the output modes to obtain a wind turbine class corresponding to each of the output modes, including: when the output mode is a large startup and large output mode or a large startup and small output mode, clustering is performed on multiple wind turbines using a K-means clustering algorithm according to the lowest transient voltage values ​​of the multiple wind turbines to obtain two wind turbine classes, wherein the lowest transient voltage value is the lowest transient voltage value of the wind turbine during a fault when a fault simulation is performed on the wind farm; when the output mode is a small startup and large output mode or a small startup and small processing mode, all the wind turbines in operation in the wind farm are taken as one wind turbine class, wherein the large startup and large output mode, the large startup and small output mode, the small startup and large output mode, and the small startup and small output mode are all the output modes.

[0009] Optionally, after constructing the equivalent model corresponding to each of the output modes according to the model parameters corresponding to each of the output modes and obtaining a plurality of the equivalent models, the method for checking transient stability of the power grid considering the wind farm output mode also includes: determining the parameters to be determined required to construct a transient recovery model for the equivalent units in the equivalent models, wherein the equivalent units are equivalent to the wind turbine units, and the transient recovery model is used to simulate the process of active power and reactive power of the equivalent units recovering from an unstable state to a stable state after a fault occurs; performing fault simulation on the wind farm to obtain the active fluctuation curve and reactive fluctuation curve of the equivalent units; solving the active fluctuation curve and the reactive fluctuation curve using the least squares method to obtain the values ​​of the parameters to be determined; and constructing the transient recovery model according to the values ​​of the parameters to be determined.

[0010] Optionally, before using each of the equivalent models to perform fault simulation on the wind farm and obtaining the power angle curve of the observed unit under each of the equivalent models, the grid transient stability verification method considering the wind farm output mode also includes: obtaining the distance between the wind farm and the power plants within a predetermined range; determining the power plant whose distance is less than a distance threshold as the target power plant; and determining any one unit in the target power plant as the observed unit.

[0011] Optionally, determining the maximum power angle difference of each power angle curve to obtain multiple maximum power angle difference values ​​includes: obtaining the original power angle value of the observed unit; determining the absolute values ​​of all the power angle values ​​in each power angle curve as absolute power angle values; sorting the multiple absolute power angle values ​​corresponding to each power angle curve in descending order to obtain multiple second sorting results; determining the maximum power angle value as the maximum power angle value corresponding to the power angle curve based on each of the second sorting results; determining the difference between each maximum power angle difference value and the original power angle value as the maximum power angle difference corresponding to the power angle curve to obtain multiple maximum power angle differences.

[0012] According to another aspect of an embodiment of the present invention, there is also provided a power grid transient stability verification device taking into account the output mode of a wind farm, comprising: a first acquisition unit, used to construct an equivalent model of a wind farm under a plurality of different output modes, and obtain a plurality of the equivalent models, wherein the wind farm is a power plant in the power grid; a second acquisition unit, used to perform fault simulation on the wind farm using each of the equivalent models, and obtain a power angle curve of an observation unit under each of the equivalent models, wherein the observation unit is used to record a power angle change curve when the wind farm is subjected to fault simulation using the equivalent model; a third acquisition unit, used to determine the maximum power angle difference of each of the power angle curves, and obtain a plurality of the maximum power angle differences. power angle difference, wherein the maximum power angle difference is the difference between the original power angle value of the observed unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observed unit before the wind farm is subjected to fault simulation using the equivalent model; a fourth acquisition unit is used to sort the multiple maximum power angle differences in descending order to obtain a first sorting result; a first determination unit is used to determine, based on the first sorting result, that the equivalent model corresponding to the largest maximum power angle difference is the target equivalent model; a fifth acquisition unit is used to perform grid transient stability verification on the wind farm using the target equivalent model to obtain a verification result so that the accuracy of the verification result reaches an accuracy threshold.

[0013] Optionally, the first acquisition unit includes: a first determination module, used to determine multiple wind turbines operating in the wind farm under each of the output modes; a first acquisition module, used to cluster the multiple wind turbines corresponding to each of the output modes, and obtain the wind turbine class corresponding to each of the output modes; a second acquisition module, used to perform equivalent processing and simplification processing on the wind turbine class corresponding to each of the output modes, and obtain model parameters corresponding to each of the output modes; a third acquisition module, used to construct the equivalent model corresponding to each of the output modes according to the model parameters corresponding to each of the output modes, and obtain multiple equivalent models.

[0014] Optionally, the output mode includes: a large startup and large output mode, a large startup and small output mode, a small startup and large output mode, and a small startup and small output mode. The first determination module includes: a first determination submodule, used to determine that all the wind turbines in the wind farm are connected to the grid and run at a rated active power value when the output mode is the large startup and large output mode; a second determination submodule, used to determine that all the wind turbines in the wind farm are connected to the grid and run at a first active power value when the output mode is the large startup and small output mode, wherein the The first active power value is a first predetermined multiple of the rated active power value; a third determination submodule is used to determine, when the output mode is the small startup and large output mode, that a predetermined number of the wind turbines in the wind farm are all connected to the grid and operated at the rated active power value, wherein the predetermined number is a second predetermined multiple of the total number of all the wind turbines; a fourth determination submodule is used to determine, when the output mode is the small startup and small output mode, that the predetermined number of the wind turbines in the wind farm are all connected to the grid and operated at the first active power value.

[0015] Optionally, the first acquisition module includes: a first acquisition submodule, used for, when the output mode is a large startup and large output mode or a large startup and small output mode, clustering multiple wind turbines using a K-means clustering algorithm according to the lowest transient voltage values ​​of the multiple wind turbines to obtain two wind turbine classes, wherein the lowest transient voltage value is the lowest transient voltage value of the wind turbine during a fault when a fault simulation is performed on the wind farm; a second acquisition submodule, used for, when the output mode is a small startup and large output mode or a small startup and small processing mode, treating all the operating wind turbines in the wind farm as one wind turbine class, wherein the large startup and large output mode, the large startup and small output mode, the small startup and large output mode and the small startup and small output mode are all the output modes.

[0016] Optionally, the grid transient stability verification device considering the wind farm output mode also includes: a second determination module, which is used to construct the equivalent model corresponding to each of the output modes according to the model parameters corresponding to each of the output modes, and after obtaining multiple equivalent models, determine the parameters to be determined required to construct a transient recovery model for the equivalent units in the equivalent models, wherein the equivalent units are equivalent to the wind turbine units, and the transient recovery model is used to simulate the process of active power and reactive power of the equivalent units recovering from an unstable state to a stable state after a fault occurs; a fourth acquisition module, which is used to perform fault simulation on the wind farm to obtain the active power fluctuation curve and reactive power fluctuation curve of the equivalent units; a fifth acquisition module, which is used to solve the active power fluctuation curve and the reactive power fluctuation curve using the least squares method to obtain the values ​​of the parameters to be determined; and a construction module, which is used to construct the transient recovery model according to the values ​​of the parameters to be determined.

[0017] Optionally, the grid transient stability verification device taking into account the wind farm output mode further includes: a sixth acquisition unit, used to obtain the distance between the wind farm and the power plants within a predetermined range before performing fault simulation on the wind farm using each of the equivalent models to obtain the power angle curve of the observed unit under each of the equivalent models; a second determination unit, used to determine that the power plant whose distance is less than a distance threshold is the target power plant; and a third determination unit, used to determine that any one unit in the target power plant is the observed unit.

[0018] Optionally, the third acquisition unit includes: a sixth acquisition module, used to acquire the original power angle value of the observed unit; a third determination module, used to determine that the absolute values ​​of all the power angle values ​​in each power angle curve are absolute power angle values; a sixth acquisition module, used to sort the multiple absolute power angle values ​​corresponding to each power angle curve in descending order, and obtain multiple second sorting results; a fourth determination module, used to determine, according to each of the second sorting results, that the largest power angle value is the maximum power angle value corresponding to the power angle curve; a seventh acquisition module, used to determine that the difference between each maximum power angle difference value and the original power angle value is the maximum power angle difference value corresponding to the power angle curve, and obtain multiple maximum power angle differences.

[0019] According to another aspect of an embodiment of the present invention, a grid transient stability verification system considering wind farm output mode is provided, and the grid transient stability verification system considering wind farm output mode uses any of the above-mentioned grid transient stability verification methods considering wind farm output mode.

[0020] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, the computer-readable storage medium comprising a stored program, wherein the program executes any one of the above-mentioned methods for checking transient stability of a power grid considering a wind farm output mode.

[0021] According to another aspect of an embodiment of the present invention, a processor is further provided, the processor being used to run a program, wherein when the program is run, any one of the above-mentioned methods for checking transient stability of a power grid considering a wind farm output mode is executed.

[0022] According to another aspect of an embodiment of the present invention, a computer program product is provided, comprising computer instructions, which, when executed by a processor, execute any one of the above-mentioned methods for checking transient stability of a power grid taking into account a wind farm output mode.

[0023] In an embodiment of the present invention, equivalent models of a wind farm under a plurality of different output modes are constructed to obtain a plurality of equivalent models, wherein the wind farm is a power plant in a power grid; each equivalent model is used to perform fault simulation on the wind farm respectively to obtain a power angle curve of the observation unit under each equivalent model, wherein the observation unit is used to record a power angle change curve when the wind farm is subjected to fault simulation using the equivalent model; the maximum power angle difference of each power angle curve is determined to obtain a plurality of maximum power angle differences, wherein the maximum power angle difference is the difference between an original power angle value of the observation unit and a maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observation unit before the wind farm is subjected to fault simulation using the equivalent model; the plurality of maximum power angle differences are sorted in descending order to obtain a first sorting result; the equivalent model corresponding to the largest maximum power angle difference is determined as a target equivalent model according to the first sorting result; the target equivalent model is used to perform grid transient stability verification on the wind farm to obtain a verification result, so that the accuracy of the verification result reaches an accuracy threshold. Through the above technical scheme, the purpose of constructing equivalent models of wind farms under a variety of different output modes and selecting the equivalent model with the largest maximum power angle difference as the target equivalent model for checking the transient stability of the wind farm power grid is achieved, and the technical effect of selecting the equivalent model with the greatest impact on the transient stability of the power grid for transient stability check by comprehensively considering the operation mode of the power grid is achieved, thereby improving the accuracy of transient stability check of the power grid, and thus solving the technical problem in related technologies that when using traditional methods to use wind farm equivalent models to check the transient stability of the power grid, the impact of the operation mode of the wind farm on the transient stability of the power grid is not fully considered, resulting in inaccurate check results. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 It is a hardware structure block diagram of a mobile terminal of a method for checking transient stability of a power grid taking into account a wind farm output mode according to an embodiment of the present invention;

[0026] Figure 2 is a flow chart of a method for checking transient stability of a power grid taking into account a wind farm output mode according to an embodiment of the present invention;

[0027] Figure 3 is a flow chart of an optional method for checking transient stability of a power grid taking into account a wind farm output mode according to an embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of a power grid transient stability verification device considering a wind farm output mode according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] As introduced in the background technology, the conventional method in the related art uses the equivalent model of the wind farm to check the transient stability of the power grid without fully considering the impact of the operation mode of the wind farm on the transient stability of the power grid, resulting in inaccurate verification results. In view of the above defects, a method and device for checking the transient stability of the power grid considering the output mode of the wind farm is provided in an embodiment of the present invention.

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0033] The method embodiments provided in the embodiments of the present invention can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 1 is a hardware structure block diagram of a mobile terminal of a method for checking transient stability of a power grid taking into account the output mode of a wind farm according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations are shown.

[0034] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the method for checking transient stability of power grid considering the output mode of wind farm in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, the above method is implemented. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0035] According to an embodiment of the present invention, a method embodiment of a method for checking transient stability of a power grid taking into account the output mode of a wind farm is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0036] Figure 2 FIG. 1 is a flow chart of a method for checking transient stability of a power grid considering the output mode of a wind farm according to an embodiment of the present invention. Figure 2 As shown, the method comprises the following steps:

[0037] Step S202 , constructing equivalent models of a wind farm under a plurality of different output modes to obtain a plurality of equivalent models, wherein a wind farm is a power plant in a power grid.

[0038] In this embodiment, equivalent models of the wind farm under a variety of different output modes can be constructed to select a more representative equivalent model for transient check of grid stability. The movement mode and state of the wind turbines in the wind farm under different output modes are different, and the various operating states of the wind turbines have different effects on the transient stability of the grid. Therefore, by taking the operating mode of the wind farm into consideration to select a more representative equivalent model for transient check of grid stability, the impact on the transient stability of the grid can be minimized.

[0039] The power grid includes many power plants, substations, transmission lines and users; types of power plants include thermal power plants, hydropower plants, wind farms, photovoltaic power plants, etc. Wind farms are a type of power plant in the power grid.

[0040] According to the above embodiment of the present invention, in the above step S202, equivalent models of the wind farm under a plurality of different output modes are constructed to obtain a plurality of equivalent models, including: determining a plurality of wind turbines operating in the wind farm under each output mode; clustering the plurality of wind turbines corresponding to each output mode respectively to obtain a wind turbine class corresponding to each output mode; performing equivalent processing and simplification processing on the wind turbine class corresponding to each output mode respectively to obtain model parameters corresponding to each output mode; constructing an equivalent model corresponding to each output mode according to the model parameters corresponding to each output mode respectively to obtain a plurality of equivalent models.

[0041] In this embodiment, the wind turbines operating in the output mode of the wind farm and the operating status of each wind turbine can be determined, and then the operating wind turbines can be clustered. The clustered wind turbine classes are then subjected to equivalent processing and simplification, and the model parameters of the equivalent wind turbines corresponding to each type of wind turbine are obtained using conventional equivalent methods, so as to construct an equivalent model of the wind farm in each output mode.

[0042] In a specific embodiment of the present invention, a plurality of wind turbines operating in a wind farm under each output mode is determined, including: when the output mode is a large-startup and large-output mode, determining that all wind turbines in the wind farm are connected to the grid and operate at a rated active power value; when the output mode is a large-startup and small-output mode, determining that all wind turbines in the wind farm are connected to the grid and operate at a first active power value, wherein the first active power value is a first predetermined multiple of the rated active power value; when the output mode is a small-startup and large-output mode, determining that a predetermined number of wind turbines in the wind farm are connected to the grid and operate at a rated active power value, wherein the predetermined number is a second predetermined multiple of the total number of all wind turbines; when the output mode is a small-startup and small-output mode, determining that a predetermined number of wind turbines in the wind farm are connected to the grid and operate at the first active power value.

[0043] Optionally, the output modes may include but are not limited to: a large startup and large output mode, a large startup and small output mode, a small startup and large output mode, and a small startup and small output mode.

[0044] In the above embodiments of the present invention, several typical output modes such as large startup and large output mode, large startup and small output mode, small startup and large output mode and small startup and small output mode are taken as examples for detailed description. Of course, other output modes can also be analyzed according to the technical solution provided in the embodiments of the present invention based on actual conditions, and no specific restrictions are made here.

[0045] Combine the following Figure 3 The above embodiments of the present invention are described in detail. Figure 3 The flowchart is of an optional method for checking transient stability of a power grid taking into account wind farm output mode according to an embodiment of the present invention.

[0046] like Figure 3 As shown, firstly, the operation mode of the wind turbine can be determined according to the output mode of the wind farm, as follows: 1) High-power and high-output mode: Each wind turbine in the wind farm is connected to the grid and the active output of each wind turbine in the wind farm is P e , where P e is the rated active power value of the wind turbine; 2) Large startup and small output mode: All wind turbines in the wind farm are connected to the grid and the active output of each wind turbine is 0.2P e ; 3) Small start-up and high output mode: Only 20% of the wind turbines in the wind farm are connected to the grid, and the active output of each wind turbine is P e , the rest of the wind turbines are shut down, and the electrical distance between the wind turbines connected to the wind farm and the grid connection point is far; 4) Small startup and small output mode: Only 20% of the wind turbines in the wind farm are connected to the grid, and the active output of each wind turbine is 0.2P e , the rest of the units are shut down, and the electrical distance between the grid-connected units and the wind farm grid connection points is far.

[0047] In another specific embodiment of the present invention, clustering is performed on multiple wind turbines corresponding to each output mode to obtain a wind turbine class corresponding to each output mode, including: when the output mode is a large startup and large output mode or a large startup and small output mode, a K-means clustering algorithm is used to cluster multiple wind turbines according to the lowest transient voltage values ​​of the multiple wind turbines to obtain two wind turbine classes, wherein the lowest transient voltage value is the lowest transient voltage value of the wind turbine during the fault simulation of the wind farm; when the output mode is a small startup and large output mode or a small startup and small processing mode, all the operating wind turbines in the wind farm are regarded as one wind turbine class, wherein the large startup and large output mode, the large startup and small output mode, the small startup and large output mode and the small startup and small output mode are all output modes.

[0048] Specifically, wind turbine groups with similar characteristics can be combined into an equivalent unit to reduce the complexity of the model while retaining sufficient information for effective grid transient stability analysis; Figure 3 As shown in Figure 1, wind turbines can be aggregated based on output mode and minimum transient voltage, as follows:

[0049] 1) When aggregating wind turbines operating in large startup and high output mode and large startup and low output mode, it can be assumed that the wind farm consists of n wind turbines, represented by the set W: W = {w1, w2, ..., w n}, where w n The nth wind turbine is represented by the wind farm. Then, a power system model including the wind farm is established. Then, a three-phase short circuit fault is set at the busbar of the wind farm station outlet using the power system simulation software. The lowest transient voltage value of each wind turbine during the fault period is obtained through simulation, which is represented by the set U: U = {u1, u2, …, u n}, where u n is the wind turbine w obtained through fault simulation n The lowest transient voltage value during the fault period; Next, the K-means clustering algorithm can be used to divide the elements in the set U into two categories, and the corresponding wind turbines in the set W are divided into two categories according to the classification results. For each type of wind turbine, the conventional equivalent method is used to obtain the model parameters of the equivalent wind turbine corresponding to each type of wind turbine, that is, the wind turbines of the entire wind farm are simulated by two equivalent wind turbines in the large startup and high output mode and the large startup and low output mode.

[0050] 2) When aggregating wind turbines operating in the small startup and high output mode and the small startup and low output mode, the wind turbines that are started in the wind farm can be formed into a class, and the model parameters of the equivalent wind turbines corresponding to each type of wind turbines can be obtained using conventional equivalent methods, that is, in the small startup and high output mode and the small startup and low output mode, the wind turbines in the entire wind farm are simulated by one equivalent wind turbine.

[0051] In addition, as above Figure 3 As shown in the figure, the wind farm network can also be simplified based on the principle of equal network loss, as follows: First, for the complex series-parallel topology in the wind farm, it is first converted into a pure parallel network through conventional network transformation; then, based on the principle of equal network loss, the equivalent impedance corresponding to the wind turbines of the same cluster is calculated after being simulated by an equivalent unit; finally, the wind turbines of the same cluster are each represented by an equivalent wind turbine connected to the wind farm station outlet bus through the corresponding equivalent impedance, where the active power of the equivalent unit is consistent with the total active power of the wind turbines of its corresponding cluster; by simplifying the network topology of the wind farm, the complex series-parallel network can be converted into a simpler parallel network, which helps to reduce the complexity of calculation and improve the efficiency of simulation. The simplified network can be represented in the form of equivalent impedance, so that the equivalent wind turbine can more accurately simulate the dynamic behavior of the entire wind farm in the power grid.

[0052] Through the above method, the equivalent models corresponding to the wind farm in these four output modes can be established: 1) large-scale startup and high-output model; 2) large-scale startup and low-output model; 3) small-scale startup and high-output model; 4) small-scale startup and low-output model.

[0053] In an optional embodiment of the present invention, after constructing an equivalent model corresponding to each output mode according to the model parameters corresponding to each output mode and obtaining multiple equivalent models, the power grid transient stability verification method considering the wind farm output mode also includes: determining the parameters to be determined required to construct a transient recovery model for the equivalent units in the equivalent model, wherein the equivalent units are equivalent to the wind turbine units, and the transient recovery model is used to simulate the process of active power and reactive power of the equivalent units recovering from an unstable state to a stable state after a fault occurs; performing fault simulation on the wind farm to obtain the active fluctuation curve and reactive fluctuation curve of the equivalent units; solving the active fluctuation curve and the reactive fluctuation curve using the least squares method to obtain the values ​​of the parameters to be determined; and constructing a transient recovery model according to the values ​​of the parameters to be determined.

[0054] As above Figure 3As shown, in order to accurately simulate and predict the behavior of the wind farm after a power grid fault occurs, the transient recovery model of the equivalent unit after the fault can be constructed by determining the transient recovery model of the equivalent unit after the fault and the corresponding parameters. The transient recovery model includes an active recovery model and a reactive recovery model. It is assumed that the active recovery model is as follows: The reactive power recovery model is as follows: Among them, t0 represents the time when the fault disappears, t1 represents the time when the active power recovers to the time before the fault, P(t) is the active power recovery curve after the fault, Q(t) is the reactive power recovery curve after the fault, P0, k p ,P1,Q0,k q and Q1 are parameters to be determined, P0 represents the initial active power of the wind turbine when the fault occurs in the active power recovery model, k p The coefficient representing the active power recovery speed, P1 represents the new stable active power of the wind turbine after the fault disappears in the active power recovery model, Q0 represents the initial active power of the wind turbine when the fault occurs in the reactive power recovery model, k q represents the coefficient of reactive power recovery speed, Q1 represents the new stable active power reached by the wind turbine after the fault disappears in the reactive power recovery model; next, a power system model including the wind farm can be established, and a three-phase short-circuit fault can be set at the station outlet bus of the wind farm by using power system simulation software. The active and reactive fluctuation curves of the detailed model of the wind farm after the fault are obtained by simulation, and then the least squares method is used to solve the parameters to be determined in the active and reactive recovery models of the equivalent units after the fault in the four equivalent models, and then substitute them into the above formulas 1 and 2 to obtain the transient recovery model of the equivalent unit after the fault (including the active recovery model and the reactive recovery model); the transient recovery model obtained here can actually be a part of the equivalent model.

[0055] Step S204, respectively using each equivalent model to perform fault simulation on the wind farm to obtain a power angle curve of the observation unit under each equivalent model, wherein the observation unit is used to record the power angle variation curve when performing fault simulation on the wind farm using the equivalent model.

[0056] In this embodiment, a three-phase short circuit fault is set on the busbar of a conventional power plant, and the power angle curves of the observed units under the four equivalent models are obtained through simulation.

[0057] According to the above embodiment of the present invention, before the above step S204, before using each equivalent model to perform fault simulation on the wind farm and obtaining the power angle curve of the observation unit under each equivalent model, the grid transient stability verification method considering the wind farm output mode also includes: obtaining the distance between the wind farm and the power plant within a predetermined range; determining the power plant with a distance less than a distance threshold as the target power plant; and determining any one unit in the target power plant as the observation unit.

[0058] Specifically, a unit of a conventional power plant that is close to the wind farm can be selected as the observation unit based on actual conditions and needs.

[0059] Step S206, determine the maximum power angle difference of each power angle curve, and obtain multiple maximum power angle differences, wherein the maximum power angle difference is the difference between the original power angle value of the observed unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observed unit before the equivalent model is used to perform fault simulation on the wind farm.

[0060] In this embodiment, the difference between the maximum power angle value and the original power angle value in each power angle curve can be calculated to obtain the corresponding maximum power angle difference. The original power angle value here refers to the original power angle value, which is the power angle value of the observed unit before the equivalent model is used to perform fault simulation on the wind farm.

[0061] According to the above embodiment of the present invention, in the above step S206, the maximum power angle difference of each power angle curve is determined to obtain multiple maximum power angle difference values, including: obtaining the original power angle value of the observed unit; determining the absolute value of all power angle values ​​in each power angle curve as the absolute power angle value; sorting the multiple absolute power angle values ​​corresponding to each power angle curve in descending order to obtain multiple second sorting results; determining the maximum power angle value as the maximum power angle value corresponding to the power angle curve according to each second sorting result; determining the difference between each maximum power angle difference value and the original power angle value as the maximum power angle difference corresponding to the power angle curve to obtain multiple maximum power angle differences.

[0062] Specifically, the largest absolute value among the power angle values ​​in the power angle curve may be selected as the maximum power angle value, and then the corresponding maximum power angle difference may be obtained by calculating the difference between the maximum power angle value and the original power angle value.

[0063] For example, assuming that the maximum power angle difference in the large startup and large output model is: Δδ 1max =δ 1max -δ1(0), where δ 1max is the maximum absolute value in the curve δ1(t), that is, the maximum power angle value, and δ1(0) is the power angle value before the fault, that is, the original power angle value.

[0064] Step S208: sort the multiple maximum power angle differences in descending order to obtain a first sorting result.

[0065] In this embodiment, the maximum power angle differences corresponding to the four equivalent models may be sorted in descending order to obtain a sorting result.

[0066] Step S210: determining, according to the first sorting result, an equivalent model corresponding to the largest maximum power angle difference as a target equivalent model.

[0067] In this embodiment, the equivalent model corresponding to the largest maximum power angle difference may be selected as the target equivalent model.

[0068] Step S212, using the target equivalent model to perform grid transient stability verification on the wind farm, and obtaining verification results, so that the accuracy of the verification results reaches an accuracy threshold.

[0069] In this embodiment, as above Figure 3 As shown, when checking the transient stability of the power grid based on the simulated wind farm, the equivalent model corresponding to the largest maximum power angle difference (that is, the target equivalent model for verification) can be selected. The larger the maximum power angle difference, the greater the impact on the transient stability of the power grid under this output mode. If the equivalent model corresponding to the largest maximum power angle difference passes the verification of the transient stability of the power grid, it means that the equivalent model under other output modes can also pass the verification, thereby overcoming the defect that the existing power system modeling does not consider the impact of the operating status of wind turbines in the wind farm on the transient stability of the power grid, and meets the actual needs of the calculation of the power grid operation mode.

[0070] From the above, it can be seen that through the technical scheme recorded in the above embodiments of the present invention, an equivalent model of a wind farm under a variety of different output modes can be constructed to obtain multiple equivalent models, wherein the wind farm is a power plant in the power grid; each equivalent model is used to perform fault simulation on the wind farm respectively to obtain a power angle curve of the observation unit under each equivalent model, wherein the observation unit is used to record the power angle change curve when the wind farm is simulated for fault using the equivalent model; the maximum power angle difference of each power angle curve is determined to obtain multiple maximum power angle differences, wherein the maximum power angle difference is the difference between the original power angle value of the observation unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observation unit before the wind farm is simulated for fault using the equivalent model. Angle value; sort multiple maximum power angle differences in descending order to obtain a first sorting result; determine the equivalent model corresponding to the largest maximum power angle difference as the target equivalent model according to the first sorting result; use the target equivalent model to perform grid transient stability verification on the wind farm to obtain a verification result, so that the accuracy of the verification result reaches the accuracy threshold, thereby achieving the purpose of constructing equivalent models of wind farms under a variety of different output modes, and selecting the equivalent model with the largest maximum power angle difference as the target equivalent model to perform grid transient stability verification on the wind farm, achieving the technical effect of selecting the equivalent model with the greatest impact on the transient stability of the grid for transient stability verification by comprehensively considering the operation mode of the grid, and improving the accuracy of transient stability verification of the grid.

[0071] Therefore, the technical solution provided by the above-mentioned embodiment of the present invention solves the technical problem that when using the traditional method in the related art to perform transient stability verification of the power grid using the wind farm equivalent model, the impact of the operation mode of the wind farm on the transient stability of the power grid is not fully considered, resulting in inaccurate verification results.

[0072] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0073] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0074] According to an embodiment of the present invention, there is also provided a power grid transient stability verification device considering wind farm output mode for implementing the above-mentioned power grid transient stability verification method considering wind farm output mode. Figure 4 is a schematic diagram of a power grid transient stability verification device considering a wind farm output mode according to an embodiment of the present invention, such as Figure 4 As shown, the device includes: a first acquisition unit 401, a second acquisition unit 403, a third acquisition unit 405, a fourth acquisition unit 407, a first determination unit 409 and a fifth acquisition unit 411. The power grid transient stability verification device considering the wind farm output mode is described in detail below.

[0075] The first acquisition unit 401 is used to construct equivalent models of a wind farm under multiple different output modes to obtain multiple equivalent models, wherein a wind farm is a power plant in a power grid.

[0076] The second acquisition unit 403 is used to perform fault simulation on the wind farm using each equivalent model to obtain the power angle curve of the observation unit under each equivalent model, wherein the observation unit is used to record the power angle change curve when the wind farm is simulated using the equivalent model.

[0077] The third acquisition unit 405 is used to determine the maximum power angle difference of each power angle curve, and obtain multiple maximum power angle differences, wherein the maximum power angle difference is the difference between the original power angle value of the observed unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observed unit before the equivalent model is used to perform fault simulation on the wind farm.

[0078] The fourth obtaining unit 407 is used to sort the multiple maximum power angle differences in descending order to obtain a first sorting result.

[0079] The first determining unit 409 is used to determine, according to the first sorting result, the equivalent model corresponding to the largest maximum power angle difference as the target equivalent model.

[0080] The fifth acquisition unit 411 is used to perform grid transient stability verification on the wind farm using the target equivalent model to obtain a verification result so that the accuracy of the verification result reaches an accuracy threshold.

[0081] It should be noted here that the above-mentioned first acquisition unit 401, second acquisition unit 403, third acquisition unit 405, fourth acquisition unit 407, first determination unit 409 and fifth acquisition unit 411 correspond to steps S202 to S212 in the above-mentioned embodiments, and the six units are the same as the instances and application scenarios implemented by the corresponding steps, but are not limited to the contents disclosed in the above-mentioned embodiments.

[0082] As can be seen from the above, in the scheme recorded in the above-mentioned embodiment of the present invention, the first acquisition unit can be used to construct an equivalent model of the wind farm under a variety of different output modes to obtain multiple equivalent models, wherein the wind farm is a power plant in the power grid; the second acquisition unit uses each equivalent model to perform fault simulation on the wind farm respectively to obtain the power angle curve of the observation unit under each equivalent model, wherein the observation unit is used to record the power angle change curve when the wind farm is subjected to fault simulation using the equivalent model; the third acquisition unit determines the maximum power angle difference of each power angle curve to obtain multiple maximum power angle differences, wherein the maximum power angle difference is the difference between the original power angle value of the observation unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle of the observation unit before the wind farm is subjected to fault simulation using the equivalent model. value; the fourth acquisition unit sorts multiple maximum power angle differences in descending order to obtain a first sorting result; the first determination unit determines the equivalent model corresponding to the largest maximum power angle difference as the target equivalent model according to the first sorting result; the fifth acquisition unit uses the target equivalent model to perform grid transient stability verification on the wind farm to obtain a verification result, so that the accuracy of the verification result reaches the accuracy threshold, thereby achieving the purpose of constructing equivalent models of the wind farm under a variety of different output modes, and selecting the equivalent model with the largest maximum power angle difference as the target equivalent model to perform grid transient stability verification on the wind farm, realizing the technical effect of selecting the equivalent model with the greatest impact on the transient stability of the grid for transient stability verification by comprehensively considering the operation mode of the grid, thereby improving the accuracy of transient stability verification of the grid.

[0083] Therefore, the technical solution provided by the above-mentioned embodiment of the present invention solves the technical problem that when using the traditional method in the related art to perform transient stability verification of the power grid using the wind farm equivalent model, the impact of the operation mode of the wind farm on the transient stability of the power grid is not fully considered, resulting in inaccurate verification results.

[0084] Optionally, the first acquisition unit includes: a first determination module, used to determine multiple wind turbines operating in the wind farm under each output mode; a first acquisition module, used to cluster the multiple wind turbines corresponding to each output mode, and obtain the wind turbine class corresponding to each output mode; a second acquisition module, used to perform equivalent processing and simplification processing on the wind turbine class corresponding to each output mode, and obtain model parameters corresponding to each output mode; a third acquisition module, used to construct an equivalent model corresponding to each output mode according to the model parameters corresponding to each output mode, and obtain multiple equivalent models.

[0085] Optionally, the output mode includes: a large startup and large output mode, a large startup and small output mode, a small startup and large output mode, and a small startup and small output mode. The first determination module includes: a first determination submodule, which is used to determine that all wind turbines in the wind farm are connected to the grid and operate at a rated active power value when the output mode is a large startup and large output mode; a second determination submodule, which is used to determine that all wind turbines in the wind farm are connected to the grid and operate at a first active power value when the output mode is a large startup and small output mode, wherein the first active power value is a first predetermined multiple of the rated active power value; a third determination submodule, which is used to determine that a predetermined number of wind turbines in the wind farm are connected to the grid and operate at a rated active power value when the output mode is a small startup and large output mode, wherein the predetermined number is a second predetermined multiple of the total number of all wind turbines; and a fourth determination submodule, which is used to determine that a predetermined number of wind turbines in the wind farm are connected to the grid and operate at the first active power value when the output mode is a small startup and small output mode.

[0086] Optionally, the first acquisition module includes: a first acquisition sub-module, which is used to cluster multiple wind turbines using a K-means clustering algorithm according to the lowest transient voltage values ​​of the multiple wind turbines when the output mode is a large startup and high output mode or a large startup and low output mode, so as to obtain two wind turbine classes, wherein the lowest transient voltage value is the lowest transient voltage value of the wind turbine during a fault simulation of the wind farm; a second acquisition sub-module, which is used to classify all operating wind turbines in the wind farm as one wind turbine class when the output mode is a small startup and high output mode or a small startup and small processing mode, wherein the large startup and high output mode, the large startup and low output mode, the small startup and high output mode and the small startup and low output mode are all output modes.

[0087] Optionally, the grid transient stability verification device considering the wind farm output mode also includes: a second determination module, which is used to construct an equivalent model corresponding to each output mode according to the model parameters corresponding to each output mode, and after obtaining multiple equivalent models, determine the parameters to be determined required to construct a transient recovery model for the equivalent units in the equivalent model, wherein the equivalent units are equivalent to the wind turbine units, and the transient recovery model is used to simulate the process of active power and reactive power of the equivalent units recovering from an unstable state to a stable state after a fault occurs; a fourth acquisition module, which is used to perform fault simulation on the wind farm to obtain the active power fluctuation curve and reactive power fluctuation curve of the equivalent units; a fifth acquisition module, which is used to solve the active power fluctuation curve and the reactive power fluctuation curve using the least squares method to obtain the values ​​of the parameters to be determined; a construction module, which is used to construct a transient recovery model according to the values ​​of the parameters to be determined.

[0088] Optionally, the grid transient stability verification device taking into account the wind farm output mode also includes: a sixth acquisition unit, used to obtain the distance between the wind farm and the power plants within a predetermined range before using each equivalent model to perform fault simulation on the wind farm and obtain the power angle curve of the observed unit under each equivalent model; a second determination unit, used to determine the power plant with a distance less than a distance threshold as the target power plant; and a third determination unit, used to determine any one unit in the target power plant as the observed unit.

[0089] Optionally, the third acquisition unit includes: a sixth acquisition module, used to acquire the original power angle value of the observed unit; a third determination module, used to determine that the absolute values ​​of all power angle values ​​in each power angle curve are absolute power angle values; a sixth acquisition module, used to sort the multiple absolute power angle values ​​corresponding to each power angle curve in descending order, and obtain multiple second sorting results; a fourth determination module, used to determine the maximum power angle value as the maximum power angle value corresponding to the power angle curve according to each second sorting result; a seventh acquisition module, used to determine that the difference between each maximum power angle difference and the original power angle value is the maximum power angle difference corresponding to the power angle curve, and obtain multiple maximum power angle differences.

[0090] According to another aspect of an embodiment of the present invention, a grid transient stability verification system considering wind farm output mode is provided. The grid transient stability verification system considering wind farm output mode uses any of the above-mentioned grid transient stability verification methods considering wind farm output mode.

[0091] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, the computer-readable storage medium comprising a stored program, wherein the program executes any one of the above-mentioned methods for checking transient stability of a power grid considering a wind farm output mode.

[0092] Optionally, in this embodiment, the computer-readable storage medium may be located in any one of the computer terminals in a computer terminal group in a computer network, or in any one of the communication devices in a communication device group.

[0093] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: constructing equivalent models of a wind farm under a plurality of different output modes to obtain a plurality of equivalent models, wherein the wind farm is a power plant in a power grid; using each equivalent model to perform fault simulation on the wind farm respectively to obtain a power angle curve of an observation unit under each equivalent model, wherein the observation unit is used to record a power angle change curve when the wind farm is subjected to fault simulation using the equivalent model; determining a maximum power angle difference of each power angle curve to obtain a plurality of The maximum power angle difference is the difference between the original power angle value of the observed unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observed unit before the equivalent model is used to perform fault simulation on the wind farm; multiple maximum power angle differences are sorted in descending order to obtain a first sorting result; according to the first sorting result, the equivalent model corresponding to the largest maximum power angle difference is determined as the target equivalent model; the target equivalent model is used to perform transient stability verification on the wind farm to obtain a verification result, so that the accuracy of the verification result reaches the accuracy threshold.

[0094] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: determining multiple wind turbines operating in a wind farm under each output mode; clustering the multiple wind turbines corresponding to each output mode to obtain a wind turbine class corresponding to each output mode; performing equivalent processing and simplification processing on the wind turbine class corresponding to each output mode to obtain model parameters corresponding to each output mode; constructing an equivalent model corresponding to each output mode according to the model parameters corresponding to each output mode to obtain multiple equivalent models.

[0095] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: when the output mode is a large-startup and large-output mode, determining that all wind turbines in the wind farm are connected to the grid and operate at a rated active power value; when the output mode is a large-startup and small-output mode, determining that all wind turbines in the wind farm are connected to the grid and operate at a first active power value, wherein the first active power value is a first predetermined multiple of the rated active power value; when the output mode is a small-startup and large-output mode, determining that a predetermined number of wind turbines in the wind farm are connected to the grid and operate at a rated active power value, wherein the predetermined number is a second predetermined multiple of the total number of all wind turbines; when the output mode is a small-startup and small-output mode, determining that a predetermined number of wind turbines in the wind farm are connected to the grid and operate at the first active power value.

[0096] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: when the output mode is a large startup and large output mode or a large startup and small output mode, a K-means clustering algorithm is used to cluster multiple wind turbines according to their lowest transient voltage values ​​to obtain two wind turbine classes, wherein the lowest transient voltage value is the lowest transient voltage value of the wind turbine during a fault simulation of the wind farm; when the output mode is a small startup and large output mode or a small startup and small processing mode, all operating wind turbines in the wind farm are regarded as one wind turbine class, wherein the large startup and large output mode, the large startup and small output mode, the small startup and large output mode and the small startup and small output mode are all output modes.

[0097] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for executing the following steps: determining the parameters to be determined required to construct a transient recovery model for the equivalent units in the equivalent model, wherein the equivalent units are equivalent to the wind turbine units, and the transient recovery model is used to simulate the process of active power and reactive power of the equivalent units recovering from an unstable state to a stable state after a fault occurs; performing fault simulation on the wind farm to obtain the active power fluctuation curve and reactive power fluctuation curve of the equivalent units; solving the active power fluctuation curve and the reactive power fluctuation curve using the least squares method to obtain the values ​​of the parameters to be determined; and constructing a transient recovery model according to the values ​​of the parameters to be determined.

[0098] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: obtaining the distance between the wind farm and the power plants within a predetermined range; determining the power plants whose distances are less than a distance threshold as target power plants; and determining any one unit in the target power plant as an observed unit.

[0099] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: obtaining the original power angle value of the observed unit; determining that the absolute values ​​of all power angle values ​​in each power angle curve are absolute power angle values; sorting the multiple absolute power angle values ​​corresponding to each power angle curve in descending order to obtain multiple second sorting results; determining the maximum power angle value as the maximum power angle value corresponding to the power angle curve according to each second sorting result; determining the difference between each maximum power angle difference value and the original power angle value as the maximum power angle difference corresponding to the power angle curve to obtain multiple maximum power angle differences.

[0100] According to another aspect of an embodiment of the present invention, a processor is further provided, and the processor is used to run a program, wherein when the program is run, any one of the above-mentioned power grid transient stability verification methods considering the wind farm output mode is executed.

[0101] According to another aspect of an embodiment of the present invention, a computer program product is provided, comprising computer instructions, which, when executed by a processor, execute any one of the above-mentioned methods for checking transient stability of a power grid taking into account the output mode of a wind farm.

[0102] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0103] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0104] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0105] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0106] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0107] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0108] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for checking transient stability of a power grid considering the output mode of a wind farm, characterized in that: include: Constructing equivalent models of a wind farm under a plurality of different output modes to obtain a plurality of equivalent models, wherein the wind farm is a power plant in a power grid; Using each of the equivalent models to perform fault simulation on the wind farm, respectively, to obtain a power angle curve of the observation unit under each of the equivalent models, wherein the observation unit is used to record the power angle change curve when the fault simulation of the wind farm is performed using the equivalent model; Determine the maximum power angle difference of each power angle curve to obtain a plurality of the maximum power angle difference values, wherein the maximum power angle difference value is the difference between the original power angle value of the observed unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observed unit before the equivalent model is used to perform fault simulation on the wind farm; Sorting the plurality of maximum power angle differences in descending order to obtain a first sorting result; Determine, according to the first sorting result, the equivalent model corresponding to the largest maximum power angle difference as the target equivalent model; The target equivalent model is used to perform a grid transient stability check on the wind farm to obtain a check result, so that the accuracy of the check result reaches an accuracy threshold.

2. The method for checking transient stability of power grid considering wind farm output mode according to claim 1 is characterized in that: Construct equivalent models of wind farms under various output modes, and obtain multiple equivalent models, including: Determining a plurality of wind turbines operating in the wind farm under each of the output modes; Performing clustering processing on the plurality of wind turbines corresponding to each output mode respectively to obtain a wind turbine class corresponding to each output mode; Performing equal value processing and simplified processing on the wind turbine group types corresponding to each output mode respectively, to obtain model parameters corresponding to each output mode; The equivalent model corresponding to each of the output modes is constructed according to the model parameters corresponding to each of the output modes, so as to obtain a plurality of the equivalent models.

3. The method for checking transient stability of power grid considering wind farm output mode according to claim 2 is characterized in that: The output modes include: a large startup and large output mode, a large startup and small output mode, a small startup and large output mode, and a small startup and small output mode. Determining a plurality of wind turbines operating in the wind farm under each of the output modes includes: When the output mode is the large startup and large output mode, determining that all the wind turbines in the wind farm are connected to the grid and run at rated active power values; When the output mode is the large startup and small output mode, determining that all the wind turbines in the wind farm are grid-connected and operated at a first active power value, wherein the first active power value is a first predetermined multiple of the rated active power value; When the output mode is the small startup and high output mode, determining that a predetermined number of the wind turbines in the wind farm are all grid-connected and operated at the rated active power value, wherein the predetermined number is a second predetermined multiple of the total number of all the wind turbines; When the output mode is the small startup and small output mode, it is determined that the predetermined number of wind turbines in the wind farm are all grid-connected and operated at the first active power value.

4. The method for checking transient stability of power grid considering wind farm output mode according to claim 2 is characterized in that: Clustering is performed on the plurality of wind turbines corresponding to each output mode to obtain a wind turbine class corresponding to each output mode, including: In the case where the output mode is a large startup and large output mode or a large startup and small output mode, a plurality of wind turbines are clustered using a K-means clustering algorithm according to the lowest transient voltage values ​​of the plurality of wind turbines to obtain two wind turbine classes, wherein the lowest transient voltage value is the lowest transient voltage value of the wind turbine during a fault when a fault simulation is performed on the wind farm; In the case where the output mode is the small start-up and high output mode or the small start-up and small processing mode, all the wind turbines operating in the wind farm are regarded as one wind turbine class, wherein the large start-up and high output mode, the large start-up and low output mode, the small start-up and high output mode and the small start-up and low output mode are all the output modes.

5. The method for checking transient stability of power grid considering wind farm output mode according to claim 2, characterized in that: After constructing the equivalent model corresponding to each output mode according to the model parameters corresponding to each output mode to obtain a plurality of equivalent models, the method further includes: Determine the parameters to be determined required to construct a transient recovery model for the equivalent unit in the equivalent model, wherein the equivalent unit is a unit equivalent to the wind turbine unit, and the transient recovery model is used to simulate the process of active power and reactive power of the equivalent unit recovering from an unstable state to a stable state after a fault occurs; Performing fault simulation on the wind farm to obtain active power fluctuation curve and reactive power fluctuation curve of the equivalent unit; Solving the active power fluctuation curve and the reactive power fluctuation curve using the least square method to obtain the value of the parameter to be determined; The transient recovery model is constructed according to the value of the parameter to be determined.

6. The method for checking transient stability of power grid considering wind farm output mode according to claim 1, characterized in that: Before respectively using each of the equivalent models to perform fault simulation on the wind farm to obtain the power angle curve of the observed unit under each of the equivalent models, the method further includes: Obtaining the distance between the wind farm and power plants within a predetermined range; Determine the power plant whose distance is less than a distance threshold as a target power plant; Determine any one unit in the target power plant as the observed unit.

7. The method for checking transient stability of power grid considering wind farm output mode according to claim 1, characterized in that: Determining the maximum power angle difference of each power angle curve to obtain a plurality of the maximum power angle differences comprises: Acquiring the original power angle value of the observed generator set; Determine the absolute value of all the power angle values ​​in each of the power angle curves as an absolute power angle value; sorting the plurality of absolute power angle values ​​corresponding to each of the power angle curves in descending order to obtain a plurality of second sorting results; Determine, according to each of the second sorting results, respectively, the maximum power angle value as the maximum power angle value corresponding to the power angle curve; The difference between each of the maximum power angle difference values ​​and the original power angle value is determined as the maximum power angle difference value corresponding to the power angle curve, and a plurality of the maximum power angle difference values ​​are obtained.

8. A power grid transient stability verification device considering wind farm output mode, characterized in that: include: A first acquisition unit is used to construct equivalent models of a wind farm under multiple different output modes to obtain multiple equivalent models, wherein the wind farm is a power plant in a power grid; A second acquisition unit is used to respectively use each of the equivalent models to perform fault simulation on the wind farm, and obtain a power angle curve of the observation unit under each of the equivalent models, wherein the observation unit is used to record the power angle change curve when the fault simulation of the wind farm is performed using the equivalent model; A third acquisition unit is used to determine the maximum power angle difference of each power angle curve to obtain a plurality of the maximum power angle differences, wherein the maximum power angle difference is the difference between the original power angle value of the observed unit and the maximum power angle value in the power angle curve, and the original power angle value is the power angle value of the observed unit before the equivalent model is used to perform fault simulation on the wind farm; a fourth obtaining unit, configured to sort the plurality of maximum power angle differences in descending order to obtain a first sorting result; A first determining unit, configured to determine, according to the first sorting result, the equivalent model corresponding to the largest maximum power angle difference as a target equivalent model; The fifth acquisition unit is used to perform a grid transient stability check on the wind farm using the target equivalent model to obtain a check result, so that the accuracy of the check result reaches an accuracy threshold.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the power grid transient stability verification method considering the wind farm output mode as described in any one of claims 1 to 7.

10. A computer program product comprising computer instructions, characterized in that: When the computer instructions are executed by the processor, the method for checking transient stability of a power grid taking into account the output mode of a wind farm as described in any one of claims 1 to 7 is performed.

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