Photovoltaic power station single-machine equivalent model parameter identification method and device

Abstract

The invention discloses a photovoltaic power station single-machine equivalent model parameter identification method, which performs optimization identification on control parameters of a converter on the basis of a traditional single-machine equivalent model, and constructs an electromagnetic transient model of a photovoltaic power station according to electrical equipment parameters and an operation scene of the photovoltaic power station. Parameter identification of a single-machine equivalent model is carried out based on an electromagnetic transient model, key parameters needing to be identified are determined and include equivalent machine parameters, equivalent box substation parameters, equivalent current collection line parameters and equivalent machine control parameters, the equivalent machine control parameters consider the relation between voltage and current amplitude limiting, the difference of the running states of photovoltaic units is considered, and the equivalent box substation parameters are determined to be equivalent to the equivalent machine parameters. The method can effectively solve the equivalence process of different types of photovoltaic power generation units, improves the simulation precision of the photovoltaic power station connected to a power grid, and provides certain reference significance for the photovoltaic power station connected to a power system.

Description

Technical Field

[0001] The present invention belongs to power system site modeling technology, and in particular to a method and device for identifying parameters of a single-machine equivalent model of a photovoltaic power station. Background Art

[0002] Photovoltaic power stations can use solar energy in a large-scale and concentrated manner and efficiently. In recent years, the installed capacity has increased rapidly and has good development prospects. However, there are many photovoltaic power generation units in large photovoltaic power stations. Establishing a detailed model to study the grid-connected characteristics of photovoltaic power stations connected to the power system will have problems such as large simulation scale and long simulation time. The single-machine multiplication model commonly used in system-level analysis cannot accurately simulate the differences in operating conditions between units, which often leads to misjudgment of system safety and stability analysis results. It is urgent to balance accuracy and calculation amount, solve how to use the least equivalent machines and simple calculation methods, and propose a practical improved single-machine equivalent parameter identification method for the electromechanical transient model of photovoltaic power stations. This has become one of the key issues that need to be solved in the operation of power systems.

[0003] At present, there are many solutions for electromagnetic transient equivalent modeling of photovoltaic power stations, such as:

[0004] 1. Liu Xingjie et al. published “Equivalent Method of Photovoltaic Power Generation System Model Based on Electrical External Characteristics”, Transactions of China Electrotechnical Society, 2014, 29(10): 231-238. This article converts the dynamic model into a controlled voltage source model with second-order dynamic circuit characteristics based on the analysis of the steady-state and transient external characteristics of the photovoltaic power generation system. It only needs to use light intensity, temperature and fault information as input to obtain the steady-state output current before and after the fault. After determining the relevant parameters of its dynamic circuit, the entire model is established, thus completing the equivalent method of photovoltaic power generation system model based on electrical external characteristics.

[0005] 2. Yan Kai et al., “Transient Modeling and Equivalence of Photovoltaic Power Generation System”, Power System Protection and Control, 2015, 43(1): 1-8. This article introduces the common forms of photovoltaic power station access to the grid, establishes a photovoltaic power generation unit model connected to the grid through a single-stage inverter, and uses the electromagnetic transient simulation model of the photovoltaic power generation system built on PSCAD / EMTDC. On this basis, an equivalent calculation model of a photovoltaic power station composed of photovoltaic power generation units is given.

[0006] 3. Cui Xiaodan et al., “Online dynamic equivalent method for large photovoltaic power stations suitable for electromechanical transient simulation”, Automation of Electric Power Systems, 2015, 39(12): 21-26. This article proposes an online dynamic equivalent method for large photovoltaic power stations suitable for electromechanical transient simulation by calculating inverter clustering indicators online and performing clustering equivalent calculations. An equivalent scheme is formed based on the clustering indicator threshold value, thus proposing an online dynamic equivalent method for large photovoltaic power stations suitable for electromechanical transient simulation.

[0007] In summary, most of the current methods for photovoltaic power station equivalence use traditional single-machine equivalence methods or grouping strategies to perform multi-machine equivalence on photovoltaic power stations. For equivalence with different types of photovoltaic units, traditional single-machine equivalence is forced to be grouped according to the model due to its method defects, and single-machine equivalence is performed on the same type of photovoltaic units in each group. Multi-machine equivalence usually also requires finding grouping points based on the model division to perform multi-machine equivalence. The calculation process is cumbersome and the method has poor versatility. Therefore, a practical improved single-machine equivalent parameter identification method for the electromagnetic transient model of photovoltaic power stations that takes into account both calculation amount and equivalence accuracy is urgently needed. 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 photovoltaic power station, to perform single-machine equivalence on photovoltaic power stations containing photovoltaic units of different models, and to use the photovoltaic power station parameters before equivalence to perform parameter identification of the equivalent machine, so that the established single-machine equivalent model can accurately reflect the response characteristics of the actual photovoltaic power station system.

[0009] In a first aspect, the present invention provides a method for identifying parameters of a single-unit equivalent model of a photovoltaic power station, comprising:

[0010] Construct an electromagnetic transient model of the photovoltaic power station based on the electrical equipment parameters and operation scenarios of the photovoltaic power station;

[0011] The electromagnetic transient model is used to identify the equivalent parameters of a single machine, where the equivalent parameters of a single machine include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters and equivalent machine control parameters;

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

[0013] The relationship model between voltage and current limits is established using the converter control parameters of the photovoltaic power station before equivalence, and the equivalent machine control parameters are calculated based on the relationship model.

[0014] Furthermore, the relationship model between voltage and current limits is established by using the converter control parameters of the photovoltaic power station before equivalent value, and the equivalent value machine control parameters are calculated based on the relationship model, including:

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

[0016] Obtain control parameters of converters in photovoltaic power plants;

[0017] Establish a relationship model between the low voltage ride-through threshold and the converter voltage, solve the relationship model to determine the relationship between the current limit and the converter voltage, and calculate the active current of the equivalent machine when the current limit is in effect;

[0018] The active current control parameters are calculated based on the active current of the equivalent machine.

[0019] Furthermore, the relational model is expressed as follows:

[0020]

[0021] in, Indicates the active current control parameter, Represents the reactive current control parameter, represents the converter voltage, express, Indicates the low voltage cross-over threshold.

[0022] Furthermore, solving the relationship model to determine the relationship between the current limit and the converter voltage includes:

[0023] The relational model is converted into an expression about the converter voltage as follows:

[0024] ,

[0025] Solve the root of the expression about the converter voltage, and determine the converter voltage when the current is limited based on the root of the expression.

[0026] Furthermore, the equivalent box transformer parameters include:

[0027] ,

[0028] 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.

[0029] Furthermore, the equivalent collector line parameters include:

[0030] ,

[0031] in, is the electromagnetic current of the i-th photovoltaic unit before the equalization, is the equivalent electromagnetic pressure, The voltage on the low voltage side of the main transformer of the photovoltaic power station. is the equivalent collector line impedance, It indicates the rated capacity of the equivalent machine, and the subscript "eq" represents the equivalent machine.

[0032] Furthermore, the equivalent collector line parameters also include equivalent positive sequence resistance and equivalent positive sequence inductance, and the identification process includes:

[0033] ,

[0034] in, represents the equivalent positive sequence resistance of the equivalent collector line, Represents the equivalent positive-sequence inductance of the equivalent collector line.

[0035] Furthermore, the check-in machine parameters include the check-in machine basic parameters and the check-in machine operating parameters. Identification of the check-in machine operating parameters includes:

[0036] ,

[0037] Among them, n represents the number of photovoltaic units 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, It is the rated capacity of a single generator, and the subscript "eq" indicates the equivalent capacity of the same type of photovoltaic unit.

[0038] Furthermore, the basic parameters of the equivalent machine adopt the basic parameters of the photovoltaic unit of the same model before the equivalent, including basic parameters of photovoltaic cells, basic parameters of converters, control parameters during voltage ride-through, and voltage recovery control parameters.

[0039] Furthermore, 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.

[0040] In a second aspect, the present invention provides a device for identifying parameters of a single-unit equivalent model of a photovoltaic power station, comprising:

[0041] The transient modeling module is used to construct the electromagnetic transient model of the photovoltaic power station according to the electrical equipment parameters and operation scenarios of the photovoltaic power station;

[0042] A parameter identification module is used to identify equivalent parameters of a single machine using an 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 parameters;

[0043] The identification process of the control parameters of the isovalue machine includes:

[0044] The relationship model between voltage and current limits is established using the converter control parameters of the photovoltaic power station before equivalence, and the equivalent machine control parameters are calculated based on the relationship model.

[0045] In a third aspect, the present invention provides an electronic device comprising a memory storing computer executable instructions and a processor, wherein when the computer executable instructions are executed by the processor, the device executes each step of the method for identifying parameters of a single-machine equivalent model of a photovoltaic power station provided in the first aspect.

[0046] In a fourth aspect, the present invention provides a readable storage medium storing a computer executable program, which, when executed, can implement the various steps of the photovoltaic power station single machine equivalent model parameter identification method provided in the first aspect.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention proposes a method for identifying parameters of a single-machine equivalent model of a photovoltaic power station. On the basis of a traditional single-machine equivalent model, the control parameters of the converter are optimized and identified. An electromagnetic transient model of the photovoltaic power station is constructed according to the electrical equipment parameters and operation scenarios of the photovoltaic power station. The parameters of the single-machine equivalent model are identified based on the electromagnetic transient model. The key parameters that need to be identified include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters and equivalent machine control parameters. The equivalent machine control parameters take into account the relationship between voltage and current limiting and the difference in the operating states of the photovoltaic units. Further embodiments specifically propose methods for identifying these parameters. The parameter identification method proposed in the present invention can effectively solve the equivalent process containing photovoltaic power generation units of different models, improve the simulation accuracy of photovoltaic power stations connected to the power grid, and thus provide a certain reference significance for photovoltaic power stations connected to the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0050] Figure 1 This is a flow chart of a method for identifying parameters of a single-machine equivalent model of a photovoltaic power station provided by an embodiment of the present invention;

[0051] Figure 2 is a general structural diagram of a photovoltaic power generation system provided by an embodiment of the present invention;

[0052] Figure 3 It is a diagram of the electromagnetic transient model architecture of a photovoltaic power station provided by an embodiment of the present invention;

[0053] Figure 4 This is a diagram of the equivalent model architecture of a single photovoltaic power station provided by an embodiment of the present invention;

[0054] Figure 5 It is a structural diagram of a photovoltaic power station single machine equivalent model parameter identification device provided by an embodiment of the present invention;

[0055] Figure 6 This is a diagram of the electronic device architecture provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 are within the scope of protection of the present invention.

[0057] See also Figure 1 An embodiment of the present invention provides a method for identifying parameters of a single-unit equivalent model of a photovoltaic power station, comprising the following steps:

[0058] Step S110: Construct an electromagnetic transient model of the photovoltaic power station according to the electrical equipment parameters and operation scenarios of the photovoltaic power station.

[0059] The electrical equipment parameters of the photovoltaic power station obtained in this step include the basic parameters of the photovoltaic power station before equivalence, the operating parameters of the photovoltaic power station, the box transformer parameters, the main transformer parameters, the collector network topology and parameters. The electromagnetic transient model of the photovoltaic power station is established using electromagnetic simulation software. Specifically, mathematical models are established for each electrical equipment in the photovoltaic power station, and the mathematical description of a single device is coupled to the overall model to form an electromagnetic transient model that comprehensively reflects the dynamic response of the wind farm.

[0060] For example, Figure 2 The general structure of a photovoltaic power generation system is shown in the figure, which mainly includes a photovoltaic array, a voltage stabilizing circuit, a converter and its controller. Figure 3 The electromagnetic transient model obtained by modeling a photovoltaic power station is illustrated.

[0061] Step S120. Use the electromagnetic transient model to identify the equivalent parameters of a single machine, wherein the equivalent parameters of a single machine include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters and equivalent machine control parameters;

[0062] The identification process of the control parameters of the isovalue machine includes:

[0063] The relationship model between voltage and current limits is established using the converter control parameters of the photovoltaic power station before equivalence, and the equivalent machine control parameters are calculated based on the relationship model.

[0064] Specifically, the equivalent machine parameters mainly describe the inertia, damping, excitation and other characteristics of the photovoltaic unit 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 photovoltaic unit of the same model before the equivalent, including the basic parameters of the photovoltaic cell, the basic parameters of the converter, the control parameters during the voltage ride-through, the voltage recovery control parameters, and other necessary parameters. In order to maximize the modeling accuracy, the refined modeling parameters of the corresponding model photovoltaic generator set should be used as much as possible, rather than the default parameters provided by the electromagnetic simulation software.

[0065] In a further embodiment, the identification of the operating parameters of the check-in machine includes:

[0066] ,

[0067] Among them, n represents the number of photovoltaic units 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, It is the rated capacity of a single generator, and the subscript "eq" indicates the equivalent capacity of the same type of photovoltaic unit.

[0068] The equivalent box-type transformer parameters include:

[0069] ,

[0070] 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.

[0071] The equivalent collector line parameters include:

[0072] ,

[0073] in, is the electromagnetic current of the i-th photovoltaic unit before the equalization, is the equivalent electromagnetic pressure, The voltage on the low voltage side of the main transformer of the photovoltaic power station. is the equivalent collector line impedance, It indicates the rated capacity of the equivalent machine, and the subscript "eq" represents the equivalent machine.

[0074] Furthermore, the equivalent collector line parameters also include equivalent positive sequence resistance and equivalent positive sequence inductance, and the identification process includes:

[0075] ,

[0076] in, represents the equivalent positive sequence resistance of the equivalent collector line, Represents the equivalent positive-sequence inductance of the equivalent collector line.

[0077] Furthermore, the embodiment of the present invention also provides identification of equivalent machine control parameters, which mainly include active and reactive power regulation coefficients, voltage regulation and low voltage ride-through parameters, and parameters describing dynamic response characteristics (such as damping coefficient and virtual inertia). These parameters respectively reflect the dynamic behavior of the photovoltaic power station as an equivalent machine in the power grid in terms of power output balance, voltage regulation response, and when encountering grid faults (such as low voltage ride-through). Among them, the active and reactive control parameters describe how the photovoltaic power station adjusts the output active power and reactive power to maintain system power balance and stability under different operating conditions.

[0078] The control parameters of the equivalent machine include active current control parameters and reactive current control parameters, and the identification process includes:

[0079] Obtain control parameters of converters in photovoltaic power plants;

[0080] Establish a relationship model between the low voltage ride-through threshold and the converter voltage, solve the relationship model to determine the relationship between the current limit and the converter voltage, and calculate the active current of the equivalent machine when the current limit is in effect;

[0081] The active current control parameters are calculated based on the active current of the equivalent machine.

[0082] According to the low voltage ride-through mechanism, the converter will When the voltage is exceeded, the protection state is entered, thus starting the current limiting measures. When building the model, it is necessary to consider the low voltage ride-through triggering conditions, the response characteristics of the controller, and the current limiting strategy. By describing the relationship between the converter voltage and current limiting in the form of a mathematical equation, using the converter's dynamic characteristics and control algorithm, taking the low voltage ride-through threshold as the trigger point, a mapping relationship is established to illustrate how the current limiting amplitude and behavior change under different voltages.

[0083] Specifically, in the electromagnetic transient model, when the active current of the converter reaches the limit, the following relationship exists:

[0084]

[0085] in, Indicates the active current control parameter, Represents the reactive current control parameter, represents the converter voltage, express, Indicates the low voltage cross-over threshold.

[0086] Convert the above equation to voltage The expression is as follows:

[0087]

[0088] Using the root discriminant of a quadratic equation, when there are two unequal roots in the above equation, that is, Δ>0, we have:

[0089]

[0090] Simplified to:

[0091]

[0092] If there are two unequal roots, then the above voltage between the two roots The expression of is less than 0. At this time, the fault control adopts the specified current without amplitude limitation. When the equation is greater than 0 outside the two roots, the fault control is converted to amplitude limitation control.

[0093] Using Vieta's theorem for quadratic equations, we can express it as follows:

[0094]

[0095]

[0096] It can be seen that if the equation has roots, one of the roots must be greater than 0, that is, under the specified control parameters of active current and reactive current, it can be directly determined whether there is a voltage drop that causes the wind turbine to switch between limited and unlimited.

[0097] The solution of the above formula is:

[0098]

[0099] It can be seen that based on the known control parameters of the photovoltaic system, the voltage threshold in the current limiting link can be calculated.

[0100] After the voltage threshold is known, the voltage value of all wind turbine outlets can be calculated through the collector network. After finding the photovoltaic unit at the limit, the active current of the photovoltaic unit in the single-machine equivalent model is calculated as:

[0101]

[0102] in, is the active current value of the single machine equivalent model; Indicates the unit that has not reached the active current limit; Indicates the unit that has reached the active current limit.

[0103] Therefore, the active current control parameters in the single-machine equivalent model can be calculated as follows:

[0104]

[0105] Wherein, represents the equivalent converter voltage.

[0106] 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 output of the i-th generator, (i = 1, 2,..., n), represents the total power of the system.

[0107] Furthermore, after completing the parameter identification, the constructed single-machine equivalent model can be verified through the following steps, specifically including:

[0108] (1) Verification under different light intensity scenarios: Set the power generated by all photovoltaic power generation units in the photovoltaic power station to high power (P > 0.7Pn), medium power (0.4Pn < P < 0.7Pn), low power (0.2Pn < P < 0.4Pn), and full power (0.2Pn < P < 0.9Pn) scenarios 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 photovoltaic power generation unit. Verify the voltage, current, active power, and reactive power response curves at the outlet of the photovoltaic power station for the detailed model, the traditional single-machine equivalent model, and the single-machine equivalent model established in the embodiment of the present invention.

[0109] (2) Verification under different voltage dip scenarios: Set the voltage dip degree 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. The fault duration is set according to the voltage dip conditions in the low voltage ride-through detection report of the corresponding type of photovoltaic power generation unit. Verify the voltage, current, active power, and reactive power response curves at the outlet of the photovoltaic power station for the detailed model, the traditional single-machine equivalent model, and the single-machine equivalent model established in the embodiment of the present invention.

[0110] Exemplarily, Figure 4 illustrates the single-machine equivalent model of the photovoltaic power station established by using the method provided in the embodiment of the present invention.

[0111] The above embodiments provide a method for identifying parameters of a single-machine equivalent model of a photovoltaic power station, optimize and identify the control parameters of the converter based on the traditional single-machine equivalent model, build an electromagnetic transient model of the photovoltaic power station according to the electrical equipment parameters and operation scenarios of the photovoltaic power station, and identify the parameters of the single-machine equivalent model based on the electromagnetic transient model. The key parameters that need to be identified include equivalent machine parameters, equivalent box transformer parameters, equivalent collection line parameters and equivalent machine control parameters, wherein the equivalent machine control parameters take into account the relationship between voltage and current limiting and the difference in the operating status of the photovoltaic unit. Further embodiments specifically propose methods for identifying these parameters. The parameter identification method proposed in the present invention can effectively solve the equivalent process containing photovoltaic power generation units of different models, improve the simulation accuracy of photovoltaic power stations connected to the power grid, and thus provide a certain reference significance for the connection of photovoltaic power stations to the power system.

[0112] The above method disclosed can be implemented by using various forms of equipment, so the present invention also discloses a parameter identification device corresponding to the above method, and specific embodiments are given below for detailed description.

[0113] like Figure 5 As shown, an embodiment of the present invention provides a device for identifying parameters of a single-machine equivalent model of a photovoltaic power station, comprising:

[0114] A transient modeling module 502 is used to construct an electromagnetic transient model of the photovoltaic power station according to the electrical equipment parameters and operation scenarios of the photovoltaic power station;

[0115] The parameter identification module 504 is used to identify the 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 parameters;

[0116] The identification process of the control parameters of the isovalue machine includes:

[0117] The relationship model between voltage and current limits is established using the converter control parameters of the photovoltaic power station before equivalence, and the equivalent machine control parameters are calculated based on the relationship model.

[0118] The implementation principle and technical effects of the device provided in the embodiments of the present application are the same as those of the aforementioned method embodiments. For the sake of brief description, for matters not mentioned in the device embodiment, reference may be made to the corresponding contents in the aforementioned method embodiments.

[0119] The methods and related devices mentioned in the above embodiments are described with reference to the method flow charts and / or structural diagrams provided in the embodiments of the present application. Specifically, each process and / or block in the method flow charts and / or structural diagrams, as well as the combination of processes and / or blocks in the flow charts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process in the process. Figure 1 A process or multiple processes and / or structures Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or structures Figure 1 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 produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A flow or multiple flows and / or structures illustrate the steps of the functions specified in one block or multiple blocks.

[0120] The following embodiments are described by taking the method applied 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 not limited to a server or a personal laptop computer, etc. In one embodiment, the computer device can be an application server, and the application server can be a server for running an application to be tested.

[0121] See also 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 processing, 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 and / or required herein.

[0122] like Figure 6As 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;

[0123] In the embodiment 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 communicate with each other through the communication bus 4;

[0124] The processor 1 may be a central processing unit CPU, or an application-specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention, etc.;

[0125] The memory 3 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), etc., such as at least one disk memory;

[0126] The memory stores a program, and the processor can call the program stored in the memory, wherein the program is used to implement various processing flows of the above-mentioned photovoltaic power station single-machine equivalent model parameter identification solution.

[0127] An embodiment of the present invention also provides a readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the various processing flows of the photovoltaic power station stand-alone equivalent model parameter identification scheme provided in the above embodiment and / or any possible implementation method in combination with the embodiment are implemented.

[0128] The above-mentioned embodiments have described the present invention in particular detail with respect to possible scenarios, and those skilled in the art will recognize that the present invention can be practiced through other embodiments. The specific naming of components, the capitalization of terms, attributes, data structures, or any other programming or structural aspects are not mandatory or important, and the mechanisms or features of the present invention may have different names, forms, or procedures. The system may be implemented by a combination of hardware and software (as described), entirely by hardware elements, or entirely by software elements. The specific division of functions between the various system components described herein is exemplary only and not mandatory; on the contrary, the functions performed by a single system component may be performed by multiple components, or the functions performed by multiple components may be performed by a single component.

[0129] Those skilled in the art should understand that the various steps of the above disclosed method can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, optionally, they can be implemented with program codes 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 made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0130] These computing device executable programs (also referred to as programs, software, software applications, or code) include machine instructions for programmable processors, and these computing programs can be implemented using high-level procedural 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 device (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.

[0131] Certain aspects of the present invention include 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, and when implemented by software, it can be downloaded, stored on different platforms used by various operating systems and operated from the platforms.

[0132] Those skilled in the art will understand that the structures shown in the accompanying drawings are merely block diagrams of partial structures related to the scheme of the present application, and do not constitute a limitation on the terminal device to which the scheme of the present application is applied. The specific terminal device may include more or fewer components than shown in the figures, or combine certain components, or have a different arrangement of components.

[0133] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "possible design" etc. means that the specific features, structures, materials or characteristics described in conjunction 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, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0134] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying parameters of a single-unit equivalent model of a photovoltaic power station, characterized in that: include: Construct an electromagnetic transient model of the photovoltaic power station based on the electrical equipment parameters and operation scenarios of the photovoltaic power station; Using the electromagnetic transient model to identify the equivalent parameters of a single machine, wherein the equivalent parameters of a single machine include equivalent machine parameters, equivalent box transformer parameters, equivalent collector line parameters and equivalent machine control parameters; The identification process of the control parameters of the equal value machine includes: The relationship model between voltage and current limits is established by using the converter control parameters of the photovoltaic power station before equivalence, and the equivalent machine control parameters are calculated based on the relationship model.

2. The method according to claim 1, characterized in that: The method of establishing a relationship model between voltage and current limit using the converter control parameters of the photovoltaic power station before equivalent value, and calculating the equivalent value machine control parameters based on the relationship model includes: The equivalent machine control parameters include active current control parameters and reactive current control parameters; Obtain control parameters of converters in photovoltaic power plants; Establishing the relationship between the low voltage ride-through threshold and the converter voltage, solving the relationship to determine the relationship between the current limit and the converter voltage, and calculating the active current of the equivalent machine when the current limit is in effect; The active current control parameters are calculated based on the active current of the equivalent machine.

3. The method according to claim 2, characterized in that The relationship between the low voltage ride-through threshold and the converter voltage is expressed as follows: in, Indicates the active current control parameter, Represents the reactive current control parameter, represents the converter voltage, express, Indicates the low voltage cross-over threshold.

4. 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.

5. The method according to claim 1, characterized in that The equivalent collector line parameters include: ， in, is the electromagnetic current of the i-th photovoltaic unit before the equalization, is the equivalent electromagnetic pressure, The voltage on the low voltage side of the main transformer of the photovoltaic power station. is the equivalent collector line impedance, It indicates the rated capacity of the equivalent machine, and the subscript "eq" represents the equivalent machine.

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

7. 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 photovoltaic units 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, It is the rated capacity of a single generator, and the subscript "eq" indicates the equivalent capacity of the same type of photovoltaic unit.

8. A photovoltaic power station single machine equivalent model parameter identification device, characterized in that: include: The transient modeling module is used to construct the electromagnetic transient model of the photovoltaic power station according to the electrical equipment parameters and operation scenarios of the photovoltaic power station; A parameter identification module is used to identify equivalent parameters of a single machine using an 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 parameters; The identification process of the control parameters of the equal value machine includes: The relationship model between voltage and current limits is established using the converter control parameters of the photovoltaic power station before equivalence, and the equivalent machine control parameters are calculated based on the relationship model.

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 photovoltaic power station 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 photovoltaic power station as described in any one of claims 1 to 7 can be implemented.

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