Wind power plant stand-alone equivalent model parameter identification method and device

Abstract

The invention discloses a wind power plant single-machine equivalent model parameter identification method and device, and the method aims at wind power plant equivalent modeling, constructs an electromagnetic transient model of a wind power plant according to the electrical equipment parameters and operation scenes of the wind power plant, and carries out the parameter identification of a single-machine equivalent model based on the electromagnetic transient model. The key parameters needing to be identified are determined to comprise equivalent machine parameters, equivalent box transformer substation parameters, equivalent current collection line parameters and equivalent machine control gain parameters, and further, the embodiment specifically provides an identification method for the parameters; the parameter identification method provided by the invention does not need to group wind turbine generators, is simple in calculation, and improves the precision of the traditional single-machine equivalent model of the wind power plant, thereby improving the simulation accuracy of the power grid, avoiding the problem that the operation mode is too conservative due to the inaccurate wind power model, and improving the safe operation level and the wind power acceptance capability of the power grid.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system substation modeling, and particularly relates to a method and device for identifying parameters of a single-machine equivalent model of a wind farm. Background Art

[0002] With the increasingly prominent global energy and environmental problems, wind power generation accounts for an increasing proportion in the power grid due to its advantages such as cleanness, flexibility, and sustainability. There are nearly a hundred units in a large wind farm, and different fan models may be involved. The single-machine multiplication model commonly used in system-level analysis often leads to misjudgment of the results of system safety and stability analysis because it cannot accurately simulate the differences in the operating states of each unit. It is urgent to balance accuracy and computational complexity and solve how to use the fewest equivalent machines and simple calculation methods to propose an electromagnetic transient aggregation equivalent parameter identification method for a wind farm, which has become one of the key problems to be solved in power system operation.

[0003] Currently, for the electromagnetic transient equivalent modeling of wind farms, there are various solutions, such as:

[0004] 1. "Research on Aggregation Model of Doubly Fed Induction Generator Wind Farms" published by Xia Anjun et al., Power System Technology: 2015, 39(07): 1879-1885. According to the principle that the active power, reactive power, reactive power output, kinetic energy change rate, and transmission chain loss of the wind farm remain unchanged, equivalent transformation is carried out on the wind turbine, transmission chain, power generation system, and main control system of the wind turbine unit, so as to propose a single-machine equivalent modeling method for multiple wind turbine units with different input wind speeds in a wind farm.

[0005] 2. "Dynamic Modeling of Wind Farms Based on Direct-Drive Permanent Magnet Synchronous Generator Sets" published by Xia Yue et al., Power System Technology: 2014, 38(06): 1439-1445. According to the electrical parameters and output data of a 200MW standard direct-drive unit wind farm of a certain large wind farm, the equivalent wind speed is obtained by using the fan power curve, and a single-machine aggregation model of the direct-drive permanent magnet unit wind farm is established according to the traditional single-machine equivalent method, and the applicability of the single-machine aggregation method and the selection principle of the collector line in the modeling process are proposed.

[0006] 3. "Dynamic Equivalence of Direct-Drive Wind Turbine Generator Wind Farms" published by Gao Feng et al., Power System Technology: 2012, 36(12): 222-227. With the goal of consistent operating characteristics at the grid connection point, a clustering index that can reflect the operating characteristics of all direct-drive wind turbine generator sets is defined, and the direct-drive wind turbine generator sets are clustered by using the K-means clustering algorithm. Based on the principle that the power conversion characteristics of the wind turbine of the equivalent machine are the same as those of the wind turbine of a single wind turbine unit, the wind turbine parameters of the wind turbine units in the same cluster are equivalent.

[0007] In summary, most of the existing methods are to perform equivalent calculation on the wind farm by adopting traditional single - machine equivalent methods or according to optimization algorithms. The equivalent accuracy of the methods adopted is not high or the equivalent parameter identification process is relatively complex, making it difficult to be applied to engineering practice. Therefore, there is an urgent need for a method for identifying modified single - machine equivalent parameters that takes into account both the computational load and the equivalent accuracy. Summary of the Invention

[0008] Based on this, the present invention aims to propose a method and device for identifying parameters of a single - machine equivalent model of a wind farm, which equivalent different types of wind turbines in the wind farm into a single equivalent machine, and uses the parameters of the wind turbines before equivalence to identify the parameters of the equivalent machine, so that the established single - machine equivalent model can accurately reflect the response characteristics of the actual wind turbines.

[0009] In the first aspect, the present invention provides a method for identifying parameters of a single - machine equivalent model of a wind farm, including:

[0010] Construct an electromagnetic transient model of the wind farm according to the electrical equipment parameters and operating scenarios of the wind farm;

[0011] Use the electromagnetic transient model to perform single - machine equivalent parameter identification, where the single - machine equivalent parameters include equivalent machine parameters, equivalent box - transformer parameters, equivalent collector line parameters, and equivalent machine control gain parameters;

[0012] The identification process of the equivalent machine control gain parameters includes:

[0013] Calculate the equivalent machine current based on the balanced node, and perform coordinate transformation on the equivalent machine current to obtain the equivalent machine control gain parameters.

[0014] Further, calculating the equivalent machine current based on the balanced node and performing coordinate transformation on the equivalent machine current to obtain the equivalent machine control gain parameters includes:

[0015] The equivalent machine control gain parameters include active current control parameters and reactive current control parameters;

[0016] Set the grid voltage of the power grid to which the wind farm belongs as the balanced node, denoted as

[0017] ,

[0018] where, represents the grid voltage;

[0019] Calculate the current at the outlet of the wind turbine before equivalence as follows:

[0020] ,

[0021] where, is the current at the outlet of the wind turbine, is the current of the fault branch, is the current flowing into the power grid;

[0022] Calculate the fan outlet current of the equivalent machine according to the principle that the external characteristics before and after equivalence are equal as follows:

[0023] ,

[0024] wherein, is the fan outlet current of the equivalent machine;

[0025] Determine the dq coordinate system according to the orientation of the fan outlet voltage, so that the outlet voltage of the equivalent machine is aligned along the d-axis. Decompose the fan outlet current of the equivalent machine into d-axis component and q-axis component, and calculate the active current control parameter and reactive current control parameter according to the d-axis component and q-axis component as follows:

[0026] ,

[0027] wherein, is the active current control coefficient, is the reactive current control coefficient, is the threshold for entering low voltage ride-through, is the fan outlet current of the d-axis component, is the q-axis component of the fan outlet current.

[0028] Furthermore, the equivalent substation parameters include:

[0029] ,

[0030] wherein, represents the rated capacity of the equivalent transformer, represents the equivalent impedance of the transformer, is the equivalent admittance of the transformer, is the capacity of the i-th transformer before equivalence.

[0031] Furthermore, the equivalent collector line parameters include:

[0032] ,

[0033] wherein, is the generated electromagnetic current of the i-th wind turbine generator before equivalence, is the equivalent voltage, is the voltage at the low voltage side of the wind farm main transformer, is the equivalent collector line impedance, represents the rated capacity of the equivalent machine, and the subscript "eq" represents the equivalent machine.

[0034] Furthermore, the equivalent collector line parameters also include the equivalent positive sequence resistance and equivalent positive sequence inductive reactance, and the identification process includes:

[0035] ,

[0036] Wherein, represents the positive sequence resistance of the equivalent collector line, represents the positive sequence reactance of the equivalent collector line.

[0037] Furthermore, the equivalent machine parameters include the basic parameters of the equivalent machine and the operating parameters of the equivalent machine. The identification of the operating parameters of the equivalent machine includes:

[0038] ,

[0039] Wherein, n represents the number of wind turbines of the same type before equivalence, is the output of the i-th generator (i = 1, 2,..., n), is the rated power of a single generator, is the rated capacity of a single generator, and the subscript "eq" represents the equivalent machine of wind turbines of the same type.

[0040] Furthermore, the basic parameters of the equivalent machine adopt the basic parameters of wind turbines of the same type before equivalence, including wind turbine model parameters, shafting model parameters, permanent magnet synchronous generator model parameters, control parameters during voltage ride-through, and voltage recovery control parameters.

[0041] Furthermore, the operating scenario adopts a uniform power distribution scenario, expressed as , represents the output of the i-th generator, (i = 1, 2,..., n), represents the total power of the system.

[0042] In a second aspect, the present invention proposes a device for identifying the parameters of a single-machine equivalent model of a wind farm, including:

[0043] A transient modeling module, configured to construct an electromagnetic transient model of the wind farm according to the electrical equipment parameters and operating scenarios of the wind farm;

[0044] A parameter identification module, configured to perform single-machine equivalent parameter identification by using the electromagnetic transient model, wherein the single-machine equivalent parameters include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters, and equivalent machine control gain parameters;

[0045] The identification process of the equivalent machine control gain parameters includes:

[0046] Calculating the equivalent machine current based on the balanced node, and performing coordinate transformation on the equivalent machine current to obtain the equivalent machine control gain parameters.

[0047] In a third aspect, the present invention provides an electronic device, including a memory storing computer-executable instructions and a processor. When the computer-executable instructions are executed by the processor, the device performs each step of the method for identifying parameters of a single-machine equivalent model of a wind farm provided in the first aspect.

[0048] In a fourth aspect, the present invention provides a readable storage medium storing a computer-executable program, which can implement each step of the method for identifying parameters of a single-machine equivalent model of a wind farm provided in the first aspect when the program is executed.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] The present invention proposes a method for identifying parameters of a single-machine equivalent model of a wind farm. For the equivalent modeling of a wind farm, it retains the advantages of the single-machine equivalent method, such as no need for clustering, simple calculation, and easy implementation in engineering. An electromagnetic transient model of the wind farm is constructed according to the electrical equipment parameters and operating scenarios of the wind farm. Based on the electromagnetic transient model, parameter identification of the single-machine equivalent model is carried out, and the key parameters to be identified are determined, including equivalent machine parameters, equivalent transformer parameters, equivalent collector line parameters, and equivalent machine control gain parameters. Further embodiments specifically propose methods for identifying these parameters. The parameter identification method proposed by the present invention does not require clustering of wind turbines and has simple calculation, which improves the accuracy of the traditional single-machine equivalent model of the wind farm, thereby improving the simulation accuracy of the power grid, avoiding the problem of overly conservative operating modes due to inaccurate wind power models, and improving the safe operation level of the power grid and the wind power acceptance capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0052] Figure 1 is a flowchart for implementing the method for identifying parameters of a single-machine equivalent model of a wind farm provided by an embodiment of the present invention;

[0053] Figure 2 is a general structure diagram of a direct-drive wind turbine provided by an embodiment of the present invention;

[0054] Figure 3 is an electromagnetic transient model architecture diagram of a certain wind farm provided by an embodiment of the present invention;

[0055] Figure 4 is a single-machine equivalent model architecture diagram of a wind farm provided by an embodiment of the present invention;

[0056] Figure 5 It is the structure diagram of the single - machine equivalent model parameter identification device provided by the embodiment of the present invention;

[0057] Figure 6 It is the architecture diagram of the electronic device provided by the embodiment of the present invention. Specific embodiments

[0058] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0059] Refer to Figure 1 , an embodiment of the present invention provides a method for identifying single - machine equivalent model parameters of a wind farm, including the following steps:

[0060] Step S110. Construct an electromagnetic transient model of the wind farm according to the electrical equipment parameters and operating scenarios of the wind farm.

[0061] The electrical equipment parameters of the wind farm obtained in this step include the basic parameters of the wind turbine before equivalence, the operating parameters of the wind turbine, the box - type transformer parameters, the main - transformer parameters, the topology and parameters of the collector network. An electromagnetic transient model of the wind turbine is established using electromagnetic simulation software. Specifically, mathematical models are established for each electrical equipment in the wind farm, and the mathematical descriptions of individual equipment are coupled into the overall model to form an electromagnetic transient model that comprehensively reflects the dynamic response of the wind farm.

[0062] Exemplarily, Figure 2 schematically shows a general structure of a direct - drive wind turbine, mainly including a wind turbine model, a shafting model, a back - to - back power electronic converter model, a step - up transformer model, a machine - side controller, and a grid - side controller model. Figure 3 schematically shows an electromagnetic transient model obtained by modeling a certain wind farm.

[0063] Step S120. Use the electromagnetic transient model to perform single - machine equivalent parameter identification, where the single - machine equivalent parameters include equivalent machine parameters, equivalent box - type transformer parameters, equivalent collector line parameters, and equivalent machine control gain parameters;

[0064] The identification process of the equivalent machine control gain parameters includes:

[0065] Calculate the equivalent machine current based on the balanced node, and perform coordinate transformation on the equivalent machine current to obtain the equivalent machine control gain parameters.

[0066] Specifically, the equivalent machine parameters mainly describe the inertia, damping, excitation and other characteristics of the wind turbine as a power generation device during the electromagnetic transient process, including the basic parameters of the equivalent machine and the operating parameters of the equivalent machine. The basic parameters of the equivalent machine adopt the basic parameters of the same type of wind turbine before equivalence, including the wind turbine model parameters, shafting model parameters, permanent magnet synchronous generator model parameters, control parameters during voltage ride-through, and voltage recovery control parameters. For a further implementation mode, in order to maximize the modeling accuracy, refined modeling parameters of the corresponding type of wind turbine should be used as much as possible, rather than the default parameters provided by the electromagnetic simulation software.

[0067] In a further embodiment, the identification of the operating parameters of the equivalent machine includes:

[0068] ,

[0069] where n represents the number of wind turbines of the same type before equivalence, is the output of the i-th generator (i = 1, 2,..., n), is the rated power of a single generator, is the rated capacity of a single generator, and the subscript "eq" represents the equivalent machine of the same type of wind turbine.

[0070] The equivalent substation parameters include:

[0071] ,

[0072] where, represents the rated capacity of the equivalent transformer, represents the equivalent impedance of the transformer, is the equivalent admittance of the transformer, is the capacity of the i-th transformer before equivalence.

[0073] The equivalent collector line parameters include:

[0074] ,

[0075] where, is the generated electromagnetic current of the i-th wind turbine before equivalence, is the equivalent voltage, is the voltage at the low-voltage side of the main transformer of the wind farm, is the equivalent impedance of the collector line, represents the rated capacity of the equivalent machine, and the subscript "eq" represents the equivalent machine.

[0076] Furthermore, the equivalent collector line parameters also include the equivalent positive-sequence resistance and the equivalent positive-sequence inductive reactance, and the identification process includes:

[0077] ,

[0078] Among them, represents the positive-sequence resistance of the equivalent collector line, represents the positive-sequence reactance of the equivalent collector line.

[0079] Furthermore, the embodiment of the present invention also provides the identification of the equivalent machine control gain parameters. The equivalent machine control gain parameters reflect the gain characteristics of the fan current control loop (including active and reactive power control) in the dynamic response. These parameters determine the response amplitude and speed of the fan output current through the controller when facing grid disturbances, and are important parameters to ensure the overall dynamic performance of the wind farm.

[0080] Specifically, the identification process of the equivalent machine control gain parameters includes:

[0081] Based on the balanced node, calculate the equivalent machine current, and perform coordinate transformation on the equivalent machine current to obtain the equivalent machine control gain parameters.

[0082] Using the electromagnetic transient model, calculate the fan outlet current through the fault branch current and the current data flowing into the grid. According to the principle of equal external characteristics before and after equivalence, take the calculated fan outlet current as the fan outlet current of the equivalent machine in the single-machine equivalent model. According to the orientation of the fan outlet voltage, determine the dq coordinate system, where the d-axis is consistent with the orientation of the fan outlet voltage, and the q-axis is perpendicular to the d-axis. Decompose the fan outlet current of the equivalent machine into d-axis and q-axis components in the dq coordinate system to represent the active and reactive power components respectively.

[0083] Furthermore, the equivalent machine control gain parameters include the active current control parameter and the reactive current control parameter, and the identification process includes:

[0084] Set the grid voltage of the power grid to which the wind farm belongs as the balanced node, denoted as

[0085] ,

[0086] Among them, represents the grid voltage;

[0087] Calculate the fan outlet current before equivalence as follows:

[0088] ,

[0089] Among them, is the fan outlet current, is the fault branch current, is the current flowing into the grid;

[0090] Calculate the fan outlet current of the equivalent machine according to the principle of equal external characteristics before and after equivalence as follows:

[0091] ,

[0092] Among them, is the fan outlet current of the equivalent machine;

[0093] Determine the dq coordinate system according to the orientation of the fan outlet voltage, so that the outlet voltage of the equivalent machine is aligned along the d-axis, decompose the fan outlet current of the equivalent machine into d-axis component and q-axis component, and calculate the active current control parameter and reactive current control parameter according to the d-axis component and q-axis component as follows:

[0094] ,

[0095] Among them, is the active current control coefficient, is the reactive current control coefficient, is the threshold for entering low voltage ride-through, is the fan outlet current of the d-axis component, is the q-axis component of the fan outlet current.

[0096] In a further embodiment, when the wind farm does not provide an operating scenario, a uniform power distribution scenario is adopted, denoted as , represents the total power of the system.

[0097] Furthermore, after completing the parameter identification, the constructed single-machine equivalent model can also be verified through the following steps, specifically including:

[0098] (1) Verification under different wind speed scenarios: Set all the wind turbines in the wind farm to be in the high wind speed operating state (the active power generated by the wind turbines is between 0.6 p.u. and 0.9 p.u.), medium wind speed operating state (the active power generated by the wind turbines is between 0.3 p.u. and 0.6 p.u.), low wind speed operating state (the active power generated by the wind turbines is between 0.1 p.u. and 0.3 p.u.) and random wind speed operating state (the active power generated by the wind turbines is between 0.1 p.u. and 0.9 p.u.) respectively. The fault duration is set according to the voltage dip conditions in the low voltage ride-through detection report of the corresponding type of wind turbine, and verify the voltage, current, active power and reactive power response curves at the outlet of the wind farm for the electromagnetic transient model, traditional single-machine equivalent model and single-machine equivalent model established in this embodiment.

[0099] (2) Verification of different voltage sag scenarios: Set the voltage sag levels at the grid connection point to 0.2 p.u., 0.35 p.u., 0.5 p.u., 0.75 p.u., and 0.9 p.u., and set the fault duration according to the voltage sag conditions in the low voltage ride-through detection report of the corresponding type of wind turbine. Verify the voltage, current, active power, and reactive power response curves at the wind farm outlet for the electromagnetic transient model, the traditional single-machine equivalent model, and the single-machine equivalent model established in this embodiment.

[0100] Exemplarily, Figure 4 illustrates the single-machine equivalent model of a wind farm established by using the method provided in the embodiment of the present invention.

[0101] The above embodiments provide a method for identifying parameters of a single-machine equivalent model of a wind farm. For the equivalent modeling of a wind farm, the advantages of the single-machine equivalent method, such as no need for grouping, simple calculation, and easy implementation in engineering, are retained. An electromagnetic transient model of the wind farm is constructed according to the electrical equipment parameters and operating scenarios of the wind farm. Based on the electromagnetic transient model, parameter identification of the single-machine equivalent model is carried out, and the key parameters to be identified are determined to include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters, and equivalent machine control gain parameters. Further embodiments specifically propose identification methods for these parameters; the parameter identification method proposed by the present invention does not require grouping of wind turbines and has simple calculation, improves the accuracy of the traditional single-machine equivalent model of the wind farm, thereby improving the simulation accuracy of the power grid, avoiding the problem of overly conservative operating modes due to inaccurate wind power models, and improving the safe operation level of the power grid and the wind power acceptance capacity.

[0102] The above disclosed method can be implemented by various forms of devices. Therefore, the present invention also discloses a parameter identification device corresponding to the above method, and specific embodiments are given below for detailed description.

[0103] As Figure 5 shown, an embodiment of the present invention provides a parameter identification device for a single-machine equivalent model of a wind farm, including:

[0104] A transient modeling module 502, configured to construct an electromagnetic transient model of the wind farm according to the electrical equipment parameters and operating scenarios of the wind farm;

[0105] A parameter identification module 504, configured to perform single-machine equivalent parameter identification by using the electromagnetic transient model, where the single-machine equivalent parameters include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters, and equivalent machine control gain parameters;

[0106] The identification process of the equivalent machine control gain parameter includes:

[0107] Calculating the equivalent machine current based on the balanced node, and performing coordinate transformation on the equivalent machine current to obtain the equivalent machine control gain parameter.

[0108] The device provided by the embodiment of the present application has the same implementation principle and technical effects as those of the foregoing method embodiment. For a brief description, for the parts not mentioned in the device embodiment, reference may be made to the corresponding content in the foregoing method embodiment.

[0109] The methods and related devices mentioned in the foregoing embodiments are described with reference to the method flowcharts and / or structural schematic diagrams provided by the embodiments of the present application. Specifically, each process and / or block of the method flowchart and / or structural schematic diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or structural schematic Figure 1 one block or multiple blocks. These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one process or multiple processes and / or structural schematic Figure 1 one block or multiple blocks. These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one process or multiple processes and / or structural schematic one block or multiple blocks.

[0110] The following embodiments are described by taking the application of the method to a computer device as an example. It can be understood that the computer device can be any device with computing and processing functions, and can be, but is not limited to, a server or a personal laptop computer, etc. In one of the embodiments, the computer device can be an application server, and the application server can be a server for running an application program to be tested.

[0111] Refer to Figure 6, which shows a hardware block diagram of an electronic device. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present application described herein and / or claimed.

[0112] As Figure 6 shown, the electronic device includes: at least one processor 1, at least one communication interface 2, at least one memory 3, and at least one communication bus 4;

[0113] In the embodiments of the present application, the number of the processor 1, the communication interface 2, the memory 3, and the communication bus 4 is at least one, and the processor 1, the communication interface 2, and the memory 3 complete mutual communication through the communication bus 4;

[0114] The processor 1 may be a central processing unit CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention, etc.;

[0115] The memory 3 may include high-speed RAM memory and may also include non-volatile memory, etc., such as at least one disk memory;

[0116] Among them, the memory stores a program, and the processor can call the program stored in the memory. The program is used to: implement each processing flow of the aforementioned wind farm single-machine equivalent model parameter identification scheme.

[0117] The embodiments of the present invention also provide a readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements each processing flow of the wind farm single-machine equivalent model parameter identification scheme provided by any possible implementation manner of the above embodiments and / or combined embodiments.

[0118] The above embodiments have described the present invention in particular detail with respect to possible scenarios. Those skilled in the art will recognize that the present invention can be practiced through other embodiments. The specific naming of components, the case of terms, attributes, data structures, or any other programming or structural aspects are not mandatory or important. The mechanisms or features for implementing the present invention can have different names, forms, or procedures. The system can be implemented through a combination of hardware and software (as described), entirely through hardware elements, or entirely through software elements. The specific division of functions between the various system components described herein is exemplary and not mandatory; on the contrary, the functions performed by a single system component can be performed by multiple components, or the functions performed by multiple components can be performed by a single component.

[0119] Those skilled in the art should understand that each step of the above-disclosed method can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed across a network composed of multiple computing devices. Optionally, they can be implemented with program code executable by the computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. Thus, the disclosure of the embodiments of the present invention is not limited to any specific combination of hardware and software.

[0120] These programs executable by the computing device (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and can implement these computing programs using high-level procedures and / or object-oriented programming languages and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0121] Certain aspects of the present invention include the process steps and instructions described herein in the form of algorithms. It should be noted that the process steps and instructions of the present invention can be implemented in software, firmware, and / or hardware. When implemented by software, it can be downloaded and thus saved on different platforms used by various operating systems and operated from those platforms.

[0122] Those skilled in the art can understand that the structures shown in the drawings are only block diagrams of some structures related to the solution of the present application, and do not constitute a limitation on the terminal devices to which the solution of the present application is applied. The specific terminal devices may include more or fewer components than those shown in the figures, or combine some components, or have different component arrangements.

[0123] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "possible designs" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0124] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying parameters of a single-unit equivalent model of a wind farm, characterized in that: include: Construct an electromagnetic transient model of the wind farm based on the electrical equipment parameters and operation scenarios of the wind farm; Using the electromagnetic transient model to identify the equivalent parameters of a single machine, the equivalent parameters of a single machine include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters and equivalent machine control gain parameters; The identification process of the equivalent machine control gain parameter includes: The equivalent machine current is calculated based on the balance node, and the equivalent machine current is subjected to coordinate transformation to obtain the equivalent machine control gain parameter.

2. The method according to claim 1, characterized in that The equivalent machine current is calculated based on the balancing node, and the coordinate transformation of the equivalent machine current is performed to obtain the equivalent machine control gain parameter, which includes: The equivalent machine control gain parameters include active current control parameters and reactive current control parameters; The grid voltage of the wind farm is set as a balance node, expressed as ， in, Indicates the grid voltage; The fan outlet current before calculating the equivalent value is as follows: ， in, is the fan outlet current, is the fault branch current, is the current flowing into the grid; According to the principle that the external characteristics before and after the equalization are equal, the fan outlet current of the equivalent machine is calculated as follows: ， in, is the fan outlet current of the equivalent machine; Determine the dq coordinate system according to the orientation of the fan outlet voltage, so that the outlet voltage of the equivalent machine is aligned along the d axis, and decompose the fan outlet current of the equivalent machine into d-axis components and q-axis components. According to the d-axis components and q-axis components, calculate the active current control parameters and reactive current control parameters as follows: ， in, is the active current control coefficient, is the reactive current control coefficient, To enter the low voltage fault ride-through threshold, is the fan outlet current The d-axis component of is the q-axis component of the fan outlet current.

3. The method according to claim 1, characterized in that The equivalent box transformer parameters include: ， in, Indicates the rated capacity of the equivalent transformer, represents the equivalent impedance of the transformer, is the equivalent admittance of the transformer, is the capacity of the i-th transformer before equalization.

4. The method according to claim 1, characterized in that: The equivalent collector line parameters include: ， in, is the electromagnetic current generated by the i-th wind turbine before the equivalent value, is the equivalent voltage, is the low voltage side voltage of the main transformer in the wind farm, is the equivalent collector line impedance, It indicates the rated capacity of the equivalent machine, and the subscript "eq" represents the equivalent machine.

5. The method according to claim 4, characterized in that The equivalent collector line parameters also include equivalent positive sequence resistance and equivalent positive sequence inductance, including: ， in, represents the equivalent positive sequence resistance of the equivalent collector line, Represents the equivalent positive-sequence inductance of the equivalent collector line.

6. The method according to claim 1, characterized in that The value-added machine parameters include the value-added machine basic parameters and the value-added machine operating parameters. Identification of the value-added machine operating parameters includes: ， Among them, n represents the number of wind turbines of the same model before equalization, is the output of the i-th generator (i=1,2,…,n), is the rated power of a single generator, is the rated capacity of a single generator, and the subscript "eq" represents the equivalent capacity of the same type of wind turbine.

7. The method according to claim 1, characterized in that The operation scenario adopts a uniform power distribution scenario, which is expressed as , represents the output of the i-th generator, (i=1,2,…,n), Indicates the total power of the system.

8. A wind farm single-unit equivalent model parameter identification device, characterized in that: include: The transient modeling module is used to construct the electromagnetic transient model of the wind farm based on the electrical equipment parameters and operation scenarios of the wind farm; A parameter identification module, used for identifying equivalent parameters of a single machine using the electromagnetic transient model, wherein the equivalent parameters of a single machine include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters and equivalent machine control gain parameters; The identification process of the equivalent machine control gain parameter includes: The equivalent machine current is calculated based on the balance node, and the equivalent machine current is subjected to coordinate transformation to obtain the equivalent machine control gain parameter.

9. An electronic device, characterized in that: The device comprises a memory storing computer executable instructions and a processor. When the computer executable instructions are executed by the processor, the device executes the method for identifying parameters of a single-machine equivalent model of a wind farm as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: A computer executable program is stored, and when the program is executed, the method for identifying parameters of a single-machine equivalent model of a wind farm as described in any one of claims 1 to 7 can be implemented.

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