A method, device, medium and electronic equipment for determining short-circuit current in a distribution network

Abstract

The present application discloses a method, device, medium and electronic device for determining short-circuit current of a distribution network, and relates to the field of new energy distribution technology, wherein the method comprises: calculating and processing based on the output parameters and capacity parameters of each inverter in the target distribution network architecture, obtaining the first boundary threshold for stage division of the output current and grid connection point voltage of each inverter; constructing a model based on the first boundary threshold, capacity parameter and predetermined second boundary threshold corresponding to the same inverter, obtaining each short-circuit current calculation model corresponding to the same inverter; determining an admittance matrix based on the target distribution network architecture and constructing a node voltage equation based on the admittance matrix; determining the short-circuit current of the distribution network based on the rated current value of each inverter using the node voltage equation and cyclically iterating with each short-circuit current calculation model, and obtaining the short-circuit current value corresponding to each inverter. The method of the present application can improve the accuracy of short-circuit current calculation of the distribution network.

Description

Technical Field

[0001] The present invention relates to the field of new energy power distribution technology, and in particular to a method, device, storage medium and electronic equipment for determining short-circuit current in a distribution network. Background Art

[0002] With the continuous deepening of the analysis of the fault characteristics of new energy, the conclusion that new energy is manifested as a current source characteristic is generally accepted. The existing technology is to use the output current of the new energy after the fault as a constant current source with the size of the converter limit value, and solve the short-circuit current by superimposing the normal component network and the fault component network. This method is simple and easy to implement, but the existing method is not detailed enough for the fault characteristics analysis of the inverter power supply. With the increasing penetration rate of new energy in the distribution network, there is a large error in the short-circuit current calculation using the existing inverter power supply fault model. Summary of the invention

[0003] In view of this, the present invention provides a method, device, storage medium and electronic device for determining short-circuit current in a distribution network, the main purpose of which is to solve the problem of large error in short-circuit current calculation using existing inverter power supply fault models.

[0004] In order to solve the above problems, the present application provides a method for determining short-circuit current of a distribution network, comprising:

[0005] Calculating and processing the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages;

[0006] A model is constructed based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply;

[0007] Based on the target distribution network architecture, determining an admittance matrix of the target distribution network architecture, and constructing a node voltage equation of the target distribution network architecture based on the admittance matrix;

[0008] Based on the rated current value corresponding to each of the inverter power supplies, the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies are used to iteratively determine the short-circuit current of the distribution network to obtain the short-circuit current value corresponding to each of the inverter power supplies.

[0009] Optionally, the calculation and processing based on the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages specifically includes:

[0010] Constructing a model based on the rated voltage capacity parameters, the rated current capacity parameters and the predetermined standard of each of the inverter power supplies to obtain a reactive current calculation model corresponding to each of the inverter power supplies;

[0011] Models are constructed based on the pre-fault output parameters and rated current capacity parameters of each of the inverter power supplies to obtain active current calculation models corresponding to each of the inverter power supplies;

[0012] Based on the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply, calculation processing is performed to obtain a first boundary threshold for dividing the output current and the grid connection point voltage of the same inverter power supply into nonlinear relationship stages, so as to obtain the first boundary threshold corresponding to each inverter power supply.

[0013] Optionally, the model is constructed based on the first boundary threshold, the capacity parameter, and a predetermined second boundary threshold corresponding to the same inverter power supply to obtain a short-circuit current calculation model for each stage corresponding to the same inverter power supply, specifically including:

[0014] For the same inverter power supply, when the ratio of the grid connection point voltage parameter to the voltage capacity parameter after the fault is greater than or equal to the predetermined second boundary threshold, a model is constructed based on the pre-fault output parameter of the same inverter power supply and the grid connection point voltage parameter after the fault, to obtain a first-stage short-circuit current calculation model corresponding to the same inverter power supply;

[0015] When the ratio of the post-fault grid connection point voltage to the voltage capacity parameter is greater than the first boundary threshold and less than the predetermined second boundary threshold, a model is constructed based on the pre-fault output parameter, the post-fault grid connection point voltage parameter, the rated voltage capacity parameter and the rated output parameter of the same inverter power supply to obtain a second-stage short-circuit current calculation model corresponding to the same inverter power supply;

[0016] When the ratio of the grid connection point voltage to the rated voltage capacity parameter after the fault is less than the first boundary threshold, a model is constructed based on the rated output parameter and the rated voltage capacity parameter of the same inverter power supply to obtain a third-stage short-circuit current calculation model corresponding to the same inverter power supply.

[0017] Optionally, determining the admittance matrix of the target distribution network architecture based on the target distribution network architecture specifically includes:

[0018] A target distribution network architecture based on the short-circuit current to be determined is modeled using the Norton equivalent method to obtain a fault equivalent network model corresponding to the target distribution network architecture, wherein the fault equivalent network model includes: a system voltage source, at least one voltage-controlled current source, and a plurality of admittances;

[0019] An admittance matrix is ​​constructed based on the fault equivalent network model to obtain the admittance matrix corresponding to the fault equivalent network model.

[0020] Optionally, the determining of the short-circuit current of the distribution network based on the rated current value corresponding to each of the inverter power supplies by using the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies to obtain the short-circuit current value corresponding to each of the inverter power supplies specifically includes:

[0021] Performing calculation based on the rated current value corresponding to each of the inverter power supplies and a predetermined multiple to obtain an initial short-circuit current value corresponding to each of the inverter power supplies;

[0022] Based on the initial values ​​of the short-circuit currents, the node voltage equation and the short-circuit current calculation models corresponding to the inverter power supplies are used to perform a corrected current calculation process in a cyclic iteration to obtain the short-circuit current value corresponding to the inverter power supply.

[0023] Optionally, the step of performing a correction current calculation process based on each of the initial short-circuit current values ​​by using the node voltage equation and each of the short-circuit current calculation models corresponding to each of the inverter power supplies to obtain a short-circuit current value corresponding to each of the inverter power supplies specifically includes:

[0024] Based on the initial value of the short-circuit current corresponding to each of the inverter power supplies, the node voltage equation is used to perform calculation processing to obtain the initial node voltage value corresponding to each of the inverter power supplies;

[0025] Based on the initial node voltage value corresponding to the same inverter power supply, a short-circuit current calculation model corresponding to the same inverter power supply is used to perform correction calculation processing to obtain an initial correction current value of the first iteration round corresponding to the same inverter power supply;

[0026] Performing a subtraction operation based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain an initial difference value;

[0027] Performing absolute value calculation processing based on each of the initial differences to obtain a first absolute voltage value corresponding to each of the inverter power supplies;

[0028] Screening each of the first absolute voltage values ​​to obtain a first target absolute voltage value;

[0029] When the first target absolute voltage value is less than a preset threshold, each of the initial correction current values ​​is determined as a short-circuit current value corresponding to each of the inverter power supplies;

[0030] When the first target absolute voltage value is greater than or equal to a preset threshold value, the short-circuit current initial value is updated based on each of the initial corrected current values, and the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies are used based on the updated initial short-circuit current values ​​to perform the corrected current calculation process for the next iteration round, and the process is iterated in a loop until the current node voltage values ​​of the current iteration round and the intermediate node voltage values ​​of the previous round meet the preset conditions, and the current corrected current value corresponding to the same inverter power supply of the current iteration round is determined as the short-circuit current value corresponding to the same inverter power supply.

[0031] Optionally, the correction calculation process based on the initial node voltage value corresponding to the same inverter power supply is performed using a short-circuit current calculation model corresponding to the same inverter power supply to obtain an initial correction current value of the first iteration round corresponding to the same inverter power supply, specifically including:

[0032] Calculating and processing based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain a first voltage ratio;

[0033] Performing stage screening based on the first voltage ratio, the first boundary threshold, and the predetermined second boundary threshold to obtain a target stage corresponding to the first voltage ratio;

[0034] Based on the initial node voltage value, the rated voltage value and the first voltage ratio, a target short-circuit current calculation model corresponding to the target stage is used to perform calculation processing to obtain an initial corrected current value of the first iteration round corresponding to the same inverter power supply.

[0035] In order to solve the above problems, the present application provides a device for determining short-circuit current of a distribution network, comprising:

[0036] A calculation module, used to perform calculation processing based on the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture, and obtain a first boundary threshold value for dividing the output current and the grid connection point voltage of each inverter power supply into nonlinear relationship stages;

[0037] A model building module, used to build a model based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply, to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply;

[0038] A node power supply equation construction module, used to determine the admittance matrix of the target distribution network architecture based on the target distribution network architecture, and to construct a node voltage equation of the target distribution network architecture based on the admittance matrix;

[0039] A determination module is used to determine the short-circuit current of the distribution network based on the rated current value corresponding to each of the inverter power supplies by adopting the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies to obtain the short-circuit current value corresponding to each of the inverter power supplies.

[0040] In order to solve the above problem, the present application provides a storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method for determining the short-circuit current of the distribution network are implemented.

[0041] To solve the above problem, the present application provides an electronic device, comprising at least a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method for determining the short-circuit current of the distribution network when executing the computer program on the memory.

[0042] Beneficial effects of the present application: The establishment of the inverter power supply short-circuit current model in the present application takes into account the current limiting characteristics of the inverter power supply itself and the low voltage ride-through requirements of the inverter power supply, and describes the short-circuit current output by the inverter power supply during a power grid fault more accurately and meticulously. The short-circuit current is solved by a cyclic iteration method, which is independent of a specific primary topology and a specific distributed power source, and is applicable to distribution networks of any given topology, and has a wide range of applications.

[0043] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0045] Figure 1 A schematic diagram of a flow chart of a method for determining short-circuit current in a distribution network provided in an embodiment of the present application is shown;

[0046] Figure 2 A schematic diagram of a target power distribution network architecture according to an embodiment of the present application is shown;

[0047] Figure 3 A schematic diagram of a fault equivalent network model corresponding to a target distribution network architecture according to an embodiment of the present application is shown;

[0048] Figure 4 A structural block diagram of a distribution network short-circuit current determination device provided by another embodiment of the present application is shown. DETAILED DESCRIPTION

[0049] Various aspects and features of the present application are described herein with reference to the accompanying drawings.

[0050] It should be understood that various modifications may be made to the embodiments of the present application. Therefore, the above description should not be considered as limiting, but only as an example of the embodiments. Other modifications within the scope and spirit of the present application will occur to those skilled in the art.

[0051] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0052] These and other characteristics of the present application will become apparent from the following description of a preferred form of embodiment given as a non-limiting example with reference to the accompanying drawings.

[0053] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art will be able to readily implement many other equivalent forms of the present application.

[0054] The above and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings.

[0055] Specific embodiments of the present application are described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments applied for are merely examples of the present application, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that obscure the present application. Therefore, the specific structural and functional details applied for herein are not intended to be limiting, but merely serve as a basis and representative basis for the claims to teach those skilled in the art to use the present application in a variety of ways with substantially any suitable detailed structure.

[0056] This specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present application.

[0057] The present application embodiment provides a method for determining short-circuit current of a distribution network. Figure 1As shown, including:

[0058] Step S101: Calculating and processing the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages;

[0059] In the specific implementation process of this step, a model is constructed based on the rated voltage capacity parameters, rated current capacity parameters and predetermined standards of each of the inverter power supplies to obtain a reactive current calculation model corresponding to each of the inverter power supplies; the predetermined standard can be a grid-connected standard for the inverter power supply connected to the distribution network, and a specific requirement for the ability of the inverter power supply to provide reactive support during low voltage ride-through: that is, when the voltage drop at the grid connection point exceeds 10%, for every 1% voltage drop, the inverter power supply must provide at least 2% reactive current, and the response speed is required to be within 20ms. This application is applicable to the above standards. Models are constructed based on the pre-fault output parameters and rated current capacity parameters of each of the inverter power supplies to obtain an active current calculation model corresponding to each of the inverter power supplies; this application takes into account the protection of the inverter power supply, limits the short-circuit capacity of the inverter power supply, and ensures that the maximum short-circuit current output of each inverter power supply cannot exceed the first predetermined multiple of the rated current, and the first predetermined multiple can be 2 times, so as to achieve protection of each inverter power supply. Based on the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply, calculation processing is performed to obtain a first boundary threshold for dividing the output current and the grid connection point voltage of the same inverter power supply into nonlinear relationship stages, so as to obtain the first boundary thresholds corresponding to each inverter power supply. Specifically, the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply are fused to obtain a fusion model; calculation processing is performed based on the fusion model to obtain the boundary values ​​of each stage corresponding to the same inverter power supply; each boundary value is screened to obtain the first boundary threshold corresponding to the same inverter power supply, so as to obtain the first boundary threshold corresponding to each inverter power supply.

[0060] Step S102: constructing a model based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply;

[0061] In the specific implementation process of this step, for the same inverter power supply, when the ratio of the grid connection point voltage parameter to the voltage capacity parameter after the fault is greater than or equal to the predetermined second boundary threshold, a model is constructed based on the output parameter before the fault of the same inverter power supply and the grid connection point voltage parameter after the fault, and a first-stage short-circuit current calculation model corresponding to the same inverter power supply is obtained; when the ratio of the grid connection point voltage to the voltage capacity parameter after the fault is greater than the first boundary threshold and less than the predetermined second boundary threshold, a model is constructed based on the output parameter before the fault, the grid connection point voltage parameter after the fault, the rated voltage capacity parameter and the rated output parameter of the same inverter power supply to obtain a second-stage short-circuit current calculation model corresponding to the same inverter power supply; when the ratio of the grid connection point voltage to the rated voltage capacity parameter after the fault is less than the first boundary threshold, a model is constructed based on the rated output parameter and the rated voltage capacity parameter of the same inverter power supply to obtain a third-stage short-circuit current calculation model corresponding to the same inverter power supply.

[0062] Step S103: determining an admittance matrix of the target distribution network architecture based on the target distribution network architecture, and constructing a node voltage equation of the target distribution network architecture based on the admittance matrix;

[0063] In the specific implementation process of this step, the target distribution network architecture of the short-circuit current to be determined is modeled using the Norton equivalent method to obtain a fault equivalent network model corresponding to the target distribution network architecture, wherein the fault equivalent network model includes: a system voltage source, at least one voltage-controlled current source, and a plurality of admittances; an admittance matrix is ​​constructed based on the fault equivalent network model to obtain the admittance matrix corresponding to the fault equivalent network model. A node voltage equation is constructed based on the admittance matrix, the system voltage source current matrix, and the corrected current parameter matrix of each inverter power supply to obtain the node voltage equation of the target distribution network architecture.

[0064] Step S104: Based on the rated current value corresponding to each of the inverters, the node voltage equation and the short-circuit current calculation models corresponding to each of the inverters are used to iteratively determine the short-circuit current of the distribution network to obtain the short-circuit current value corresponding to each of the inverters.

[0065] In the specific implementation process of this step, calculation processing is performed based on the rated current value corresponding to each of the inverter power supplies and the predetermined multiple to obtain the initial short-circuit current value corresponding to each of the inverter power supplies; based on each of the initial short-circuit current values, the node voltage equation and the short-circuit current calculation model corresponding to each of the inverter power supplies are used to iteratively perform corrected current calculation processing to obtain the short-circuit current value corresponding to each of the inverter power supplies.

[0066] The establishment of the inverter power supply short-circuit current model in this application takes into account the current limiting characteristics of the inverter power supply itself and the low voltage ride-through requirements of the inverter power supply. It describes the short-circuit current output by the inverter power supply when a power grid fails more accurately and meticulously. The short-circuit current is solved by a cyclic iteration method, which is independent of a specific primary topology and a specific distributed power source. It is applicable to distribution networks of any given topology and has a wide range of applications.

[0067] Another embodiment of the present application provides another method for determining short-circuit current of a distribution network, including:

[0068] Step S201: constructing a model based on the rated voltage capacity parameter, the rated current capacity parameter and a predetermined standard of each of the inverter power supplies to obtain a reactive current calculation model corresponding to each of the inverter power supplies;

[0069] In the specific implementation process of this step, a model is constructed based on the rated voltage capacity parameters, rated current capacity parameters and predetermined standards of each of the inverter power supplies to obtain a reactive current calculation model corresponding to each of the inverter power supplies; the predetermined standard can be a grid connection standard for the inverter power supplies connected to the distribution network, and a specific requirement for the ability of the inverter power supply to provide reactive support during low voltage crossing: that is, when the grid connection point voltage drops by more than 10%, for every 1% voltage drop, the inverter power supply must provide at least 2% reactive current, and the response speed is required to be within 20ms. The present application is applicable to the above standards. The mathematical expression of the reactive current calculation model can be shown as follows:

[0070]

[0071] Among them, u N Indicates the rated voltage of the inverter power supply, P N is the rated capacity of the inverter power supply, Indicates the rated current of the inverter output, U g is the voltage variable parameter of the grid connection point after the fault occurs, i qref Indicates reactive current.

[0072] Step S202: constructing models based on the pre-fault output parameters and rated current capacity parameters of each of the inverter power supplies to obtain active current calculation models corresponding to each of the inverter power supplies;

[0073] In the specific implementation process of this step, the model is constructed based on the rated output parameters and rated current capacity parameters of each inverter power supply, and the active current calculation model corresponding to each inverter power supply is obtained; this application takes into account the protection of the inverter power supply, and limits the short-circuit capacity of the inverter power supply to ensure that the maximum short-circuit current output by each inverter power supply cannot exceed the first predetermined multiple of the rated current, and the first predetermined multiple can be 2 times, so as to achieve the protection of each inverter power supply. The mathematical expression of the active current calculation model can be shown as the following formula (2):

[0074]

[0075] Among them, i dref is the active current, P ref is the output parameter of the inverter power supply before failure, U g is the voltage variable parameter of the grid connection point after the fault occurs, Indicates the rated current of the inverter power output.

[0076] Step S203: performing calculation processing based on the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply to obtain a first boundary threshold for dividing the nonlinear relationship between the output current and the grid connection point voltage of the same inverter power supply into stages, so as to obtain the first boundary threshold corresponding to each inverter power supply respectively;

[0077] In the specific implementation process of this step, the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply are merged to obtain a fusion model; specifically, the mathematical expression of the reactive current calculation model is substituted into the mathematical expression of the active current calculation model to obtain the fusion model, and the mathematical expression of the fusion model can be expressed as the following formula (3):

[0078]

[0079] Based on the fusion model, calculation processing is performed to obtain the boundary values ​​of each stage corresponding to the same inverter power supply; specifically, a first calculation formula and a second calculation formula in the first stage active current calculation formula of the fusion model corresponding to the same inverter power supply are used to construct a first equation; the first equation can be expressed as the following mathematical formula (4):

[0080]

[0081] The second equation can be expressed as follows:

[0082]

[0083] Based on the first equation, the boundary value corresponding to the first stage is obtained by calculation, that is, the calculated U g value as the boundary value; based on the second equation, the boundary value corresponding to the second stage is obtained by calculation; the calculated U g Value as boundary value U * . Screen each of the boundary values ​​to obtain the first boundary threshold U corresponding to the same inverter power supply. * , to obtain the first boundary threshold U corresponding to each of the inverter power supplies * Specifically, the boundary value calculated by formula (4) does not meet the limiting conditions of the first stage. Therefore, the boundary value calculated by formula (4) is filtered out, and the boundary value calculated by formula (5) corresponding to the same inverter power supply is determined as the first boundary threshold corresponding to the same inverter power supply, so as to obtain the first boundary threshold corresponding to each inverter power supply.

[0084] Step S204: constructing a model based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply;

[0085] In the specific implementation process of this step, for the same inverter, when the ratio of the grid connection point voltage parameter to the voltage capacity parameter after the fault is greater than or equal to the predetermined second boundary threshold, a model is constructed based on the output parameter before the fault of the same inverter and the grid connection point voltage parameter after the fault, and a first-stage short-circuit current calculation model corresponding to the same inverter is obtained; when the ratio of the grid connection point voltage to the voltage capacity parameter after the fault is greater than the first boundary threshold and less than the predetermined second boundary threshold, a model is constructed based on the output parameter before the fault, the grid connection point voltage parameter after the fault, the rated voltage capacity parameter and the rated output parameter of the same inverter, and a second-stage short-circuit current calculation model corresponding to the same inverter is obtained; when the ratio of the grid connection point voltage to the rated voltage capacity parameter after the fault is less than the first boundary threshold, a model is constructed based on the rated output parameter and the rated voltage capacity parameter of the same inverter, and a third-stage short-circuit current calculation model corresponding to the same inverter is obtained. The short-circuit current calculation model corresponding to each stage of the same inverter can be expressed as the following formula (6):

[0086]

[0087] Wherein, n is the code of the inverter power supply. For example, the target distribution network architecture includes 4 inverter power supplies, then the value of n is 1-4, f represents a fault, k is the number of loop iterations, 0.9 is the second preset threshold, and U * is the first boundary threshold corresponding to each of the inverter power supplies.

[0088] Step S205: determining an admittance matrix of the target distribution network architecture based on the target distribution network architecture;

[0089] In the specific implementation process of this step, the Norton equivalent method is used to construct a model based on the target distribution network architecture of the short-circuit current to be determined, and a fault equivalent network model corresponding to the target distribution network architecture is obtained. The fault equivalent network model includes: a system voltage source, at least one voltage-controlled current source and a plurality of admittances; specifically, Figure 2 The target distribution network architecture shown in FIG. 1 has a three-phase short circuit fault at point f. The system power supply of the target distribution network architecture is represented by a traditional system voltage source, each inverter power supply is represented by a voltage-controlled current source, and the line is represented by an admittance to obtain a fault equivalent network model as shown in FIG. Figure 3 As shown: Based on the fault equivalent network model, the admittance matrix is ​​constructed to obtain the admittance matrix corresponding to the fault equivalent network model. Figure 4 The mathematical expression of the admittance matrix obtained by the fault equivalent network model shown is as shown in the following formula (7):

[0090]

[0091] Among them, Y s is the system power equivalent admittance, Y L1 -Y L4 is the line equivalent admittance, Y LD1 -Y LD3 is the load equivalent admittance, Y f is the fault grounding equivalent admittance.

[0092] Step S206: constructing a node voltage equation of the target distribution network architecture based on the admittance matrix;

[0093] In the specific implementation process of this step, the mathematical expression of the node voltage equation of the target distribution network architecture is as shown in the following formula (8):

[0094]

[0095] in, is the fault voltage corresponding to the system power supply when the number of loop iterations is k, are the fault voltages corresponding to the four inverters when the number of iterations is k, is the short-circuit current corresponding to the system power supply, is the short-circuit current corresponding to the four inverter power supplies when the number of loop iterations is k-1.

[0096] Step S207: performing calculation processing based on the rated current value corresponding to each of the inverter power supplies and the predetermined multiple to obtain the initial short-circuit current value corresponding to each of the inverter power supplies;

[0097] In the specific implementation process of this step, the predetermined multiple can be 2, and 2 times the rated current of each inverter power supply IIDG is used as the corresponding short-circuit current initial value. The mathematical formula for calculating the initial value of the short-circuit current can be expressed as follows:

[0098]

[0099] in, is the initial value of the short-circuit current, is the rated current of the nth inverter power supply.

[0100] Step S208: performing calculation processing using the node voltage equation based on the initial short-circuit current value corresponding to each of the inverter power supplies to obtain an initial node voltage value corresponding to each of the inverter power supplies;

[0101] In the specific implementation process of this step, the node voltage equation is used to perform calculation processing based on the initial short-circuit current value corresponding to each inverter power supply and the short-circuit current value corresponding to the system power supply to obtain the initial node voltage value corresponding to each inverter power supply; specifically, the initial short-circuit current value and the short-circuit current value corresponding to the system power supply are substituted into the node voltage equation for calculation processing to obtain the initial node voltage value corresponding to each inverter power supply.

[0102] Step S209: Based on the initial node voltage value corresponding to the same inverter power supply, a short-circuit current calculation model corresponding to the same inverter power supply is used to perform correction calculation processing to obtain an initial correction current value of the first iteration round corresponding to the same inverter power supply;

[0103] In the specific implementation process of this step, the initial node voltage value and the rated voltage value corresponding to the same inverter power supply are calculated and processed to obtain a first voltage ratio; the calculation formula of the first voltage ratio is shown in the following formula (10):

[0104]

[0105] Based on the first voltage ratio, the first boundary threshold and the predetermined second boundary threshold, stage screening is performed to obtain a target stage corresponding to the first voltage value; specifically, based on the first voltage ratio, screening is performed based on the range corresponding to each stage, and the target range in which the first voltage ratio falls is determined as the target stage. Based on the initial node voltage value, the rated voltage value and the first voltage ratio, a target short-circuit current calculation model corresponding to the target stage is used for calculation processing to obtain an initial corrected current value of the first iteration round corresponding to the same inverter power supply. Specifically, the initial node voltage value, the rated voltage value and the first voltage ratio are substituted into the target short-circuit current calculation model corresponding to the target stage for calculation processing to obtain an initial corrected current value of the first iteration round corresponding to the same inverter power supply.

[0106] Step S210: performing calculation processing based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain a first absolute voltage value corresponding to each inverter power supply;

[0107] In the specific implementation process of this step, a subtraction operation is performed based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain an initial difference; the calculation formula of the initial difference can be expressed as the following formula (11):

[0108]

[0109] Based on each of the initial differences, an absolute value calculation process is performed to obtain a first absolute voltage value corresponding to each of the inverter power supplies; the calculation formula of the first absolute voltage value is as shown in the following formula (12):

[0110]

[0111] Step S211: screening the first absolute voltage values ​​to obtain a first target absolute voltage value;

[0112] In the specific implementation process of this step, the first absolute voltage values ​​corresponding to each of the inverter power supplies are screened, and the maximum first absolute voltage value among the first absolute voltage values ​​is determined as the first target absolute voltage value. The mathematical expression for screening the first absolute voltage values ​​corresponding to each of the inverter power supplies is shown in the following formula (13):

[0113]

[0114] Step S212: when the first target absolute voltage value is less than a preset threshold, determining each of the initial corrected current values ​​as a short-circuit current value corresponding to each of the inverter power supplies;

[0115] In the specific implementation of this step, when the first target absolute voltage value is less than a preset threshold value, each of the initial corrected current values ​​is determined as a short-circuit current value corresponding to each of the inverter power supplies; the preset threshold ε can be set according to actual needs.

[0116] Step S213: When the first target absolute voltage value is greater than or equal to a preset threshold value, the short-circuit current initial value is updated based on each of the initial corrected current values, and based on the updated initial short-circuit current values, the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies are used to perform the corrected current calculation process for the next iteration round, and the process is iterated in a loop until the current node voltage values ​​of the current iteration round and the intermediate node voltage values ​​of the previous round meet the preset conditions, and the current corrected current value corresponding to the same inverter power supply of the current iteration round is determined as the short-circuit current value corresponding to the same inverter power supply.

[0117] In the specific implementation process of this step, when the first target absolute voltage value is greater than or equal to the preset threshold value, the initial short-circuit current value is updated based on each initial correction current value, and the node voltage equation and each short-circuit current calculation model corresponding to each inverter power supply are used based on the updated initial short-circuit current value to perform the correction current calculation process of the next iteration round, and the iteration is repeated until each current node voltage value of the current iteration round and each intermediate node voltage value of the previous round meet the preset conditions, and the current correction current value corresponding to the same inverter power supply of the current iteration round is determined as the short-circuit current value corresponding to the same inverter power supply. The mathematical expression of the preset condition can be expressed as the following formula (14):

[0118]

[0119] The preset condition may be that if the maximum absolute value of the difference between the voltage values ​​of each current node in the current iteration round and the voltage values ​​of each intermediate node in the previous round is less than a preset threshold, the iteration is terminated, and the current corrected current value corresponding to the same inverter power supply in the current iteration round is determined as the short-circuit current value corresponding to the same inverter power supply.

[0120] The establishment of the inverter power supply short-circuit current model in this application takes into account the current limiting characteristics of the inverter power supply itself and the low voltage ride-through requirements of the inverter power supply. It describes the short-circuit current output by the inverter power supply when a power grid fails more accurately and meticulously. The short-circuit current is solved by a cyclic iteration method, which is independent of a specific primary topology and a specific distributed power source. It is applicable to distribution networks of any given topology and has a wide range of applications.

[0121] Another embodiment of the present application provides a device for determining short-circuit current of a distribution network, such as Figure 4 As shown, including:

[0122] A calculation module 1 is used to calculate and process the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages;

[0123] A model building module 2, configured to build a model based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply, to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply;

[0124] A node power supply equation construction module 3 is used to determine the admittance matrix of the target distribution network architecture based on the target distribution network architecture, and to construct a node voltage equation of the target distribution network architecture based on the admittance matrix;

[0125] The determination module 4 is used to determine the short-circuit current of the distribution network based on the rated current value corresponding to each of the inverter power supplies by using the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies to iteratively obtain the short-circuit current value corresponding to each of the inverter power supplies.

[0126] In the specific implementation process, the calculation module 1 is specifically used for: constructing a model based on the rated voltage capacity parameters, rated current capacity parameters and predetermined standards of each inverter power supply to obtain a reactive current calculation model corresponding to each inverter power supply; constructing a model based on the pre-fault output parameters and rated current capacity parameters of each inverter power supply to obtain an active current calculation model corresponding to each inverter power supply; performing calculation processing based on the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply to obtain a first boundary threshold for dividing the output current and the grid-connected point voltage of the same inverter power supply into nonlinear relationship stages, so as to obtain the first boundary threshold corresponding to each inverter power supply.

[0127] In the specific implementation process, the model construction module 2 is specifically used for: for the same inverter power supply, when the ratio of the grid connection point voltage parameter to the voltage capacity parameter after the fault is greater than or equal to the predetermined second boundary threshold, the model is constructed based on the pre-fault output parameter of the same inverter power supply and the post-fault grid connection point voltage parameter to obtain the first-stage short-circuit current calculation model corresponding to the same inverter power supply; when the ratio of the grid connection point voltage to the voltage capacity parameter after the fault is greater than the first boundary threshold and less than the predetermined second boundary threshold, the model is constructed based on the pre-fault output parameter, the post-fault grid connection point voltage parameter, the rated voltage capacity parameter and the rated output parameter of the same inverter power supply to obtain the second-stage short-circuit current calculation model corresponding to the same inverter power supply; when the ratio of the grid connection point voltage to the rated voltage capacity parameter after the fault is less than the first boundary threshold, the model is constructed based on the rated output parameter and the rated voltage capacity parameter of the same inverter power supply to obtain the third-stage short-circuit current calculation model corresponding to the same inverter power supply.

[0128] In the specific implementation process, the node power equation construction module 3 is specifically used for: constructing a model based on the target distribution network architecture of the short-circuit current to be determined using the Norton equivalent method to obtain a fault equivalent network model corresponding to the target distribution network architecture, wherein the fault equivalent network model includes: a system voltage source, at least one voltage-controlled current source and a plurality of admittances; constructing an admittance matrix based on the fault equivalent network model to obtain the admittance matrix corresponding to the fault equivalent network model.

[0129] In the specific implementation process, the determination module 4 is specifically used to: perform calculation processing based on the rated current value corresponding to each of the inverter power supplies and a predetermined multiple to obtain an initial short-circuit current value corresponding to each of the inverter power supplies; perform corrected current calculation processing based on each of the initial short-circuit current values ​​using the node voltage equation and each of the short-circuit current calculation models corresponding to each of the inverter power supplies in a cyclically iterative manner to obtain a short-circuit current value corresponding to each of the inverter power supplies.

[0130] In the specific implementation process, the determination module 4 is also used to: perform calculation processing based on the initial short-circuit current value corresponding to each of the inverter power supplies using the node voltage equation to obtain the initial node voltage value corresponding to each of the inverter power supplies; perform correction calculation processing based on the initial node voltage value corresponding to the same inverter power supply using the short-circuit current calculation model corresponding to the same inverter power supply to obtain the initial corrected current value of the first iteration round corresponding to the same inverter power supply; perform subtraction processing based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain the initial difference; perform absolute value calculation processing based on each of the initial differences to obtain the first absolute voltage value corresponding to each of the inverter power supplies; screen each of the first absolute voltage values ​​to obtain the first target absolute voltage value ; When the first target absolute voltage value is less than a preset threshold value, each of the initial corrected current values ​​is determined as a short-circuit current value corresponding to each of the inverter power supplies; when the first target absolute voltage value is greater than or equal to a preset threshold value, the initial short-circuit current value is updated based on each of the initial corrected current values, and based on the updated initial short-circuit current values, the node voltage equation and the short-circuit current calculation model corresponding to each of the inverter power supplies are used to perform the corrected current calculation process for the next iteration round, and the iteration is repeated until the current node voltage values ​​of the current iteration round and the intermediate node voltage values ​​of the previous round meet the preset conditions, and the current corrected current value corresponding to the same inverter power supply of the current iteration round is determined as the short-circuit current value corresponding to the same inverter power supply.

[0131] In the specific implementation process, the determination module 4 is also used to: perform calculations based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain a first voltage ratio; perform stage screening based on the first voltage ratio, the first boundary threshold and the predetermined second boundary threshold to obtain a target stage corresponding to the first voltage ratio; perform calculations based on the initial node voltage value, the rated voltage value and the first voltage ratio using a target short-circuit current calculation model corresponding to the target stage to obtain an initial corrected current value of the first iteration round corresponding to the same inverter power supply.

[0132] The establishment of the inverter power supply short-circuit current model in this application takes into account the current limiting characteristics of the inverter power supply itself and the low voltage ride-through requirements of the inverter power supply. It describes the short-circuit current output by the inverter power supply when a power grid fails more accurately and meticulously. The short-circuit current is solved by a cyclic iteration method, which is independent of a specific primary topology and a specific distributed power source. It is applicable to distribution networks of any given topology and has a wide range of applications.

[0133] Another embodiment of the present application provides a storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the following method steps are implemented:

[0134] Step 1: Calculate and process the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages;

[0135] Step 2: constructing a model based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply;

[0136] Step 3: Based on the target distribution network architecture, determine the admittance matrix of the target distribution network architecture, and construct the node voltage equation of the target distribution network architecture based on the admittance matrix;

[0137] Step 4: Based on the rated current value corresponding to each of the inverter power supplies, the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies are used to iteratively determine the short-circuit current of the distribution network to obtain the short-circuit current value corresponding to each of the inverter power supplies.

[0138] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0139] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0140] The specific implementation process of the above method steps can refer to any of the above embodiments of the method for determining the short-circuit current of the distribution network, and this embodiment will not be repeated here.

[0141] The establishment of the inverter power supply short-circuit current model in this application takes into account the current limiting characteristics of the inverter power supply itself and the low voltage ride-through requirements of the inverter power supply. It describes the short-circuit current output by the inverter power supply when a power grid fails more accurately and meticulously. The short-circuit current is solved by a cyclic iteration method, which is independent of a specific primary topology and a specific distributed power source. It is applicable to distribution networks of any given topology and has a wide range of applications.

[0142] Another embodiment of the present application provides an electronic device, which may be a server, and the electronic device includes a processor, a memory, a network interface, and a database connected via a system bus. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile and / or volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the electronic device is used to communicate with an external client via a network connection. When the electronic device program is executed by the processor, it implements the functions or steps of a service-side method for determining short-circuit current in a distribution network.

[0143] In one embodiment, an electronic device is provided, which may be a client. The electronic device includes a processor, a memory, a network interface, a display screen, and an input device connected via a system bus. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the electronic device is used to communicate with an external server via a network connection. When the electronic device program is executed by the processor, the functions or steps on the client side of a method for determining short-circuit current in a distribution network are implemented.

[0144] Another embodiment of the present application provides an electronic device, comprising at least a memory and a processor, wherein the memory stores a computer program, and the processor implements the following method steps when executing the computer program in the memory:

[0145] Step 1: Calculate and process the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages;

[0146] Step 2: constructing a model based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply;

[0147] Step 3: Based on the target distribution network architecture, determine the admittance matrix of the target distribution network architecture, and construct the node voltage equation of the target distribution network architecture based on the admittance matrix;

[0148] Step 4: Based on the rated current value corresponding to each of the inverter power supplies, the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies are used to iteratively determine the short-circuit current of the distribution network to obtain the short-circuit current value corresponding to each of the inverter power supplies.

[0149] The specific implementation process of the above method steps can refer to any of the above embodiments of the method for determining the short-circuit current of the distribution network, and this embodiment will not be repeated here.

[0150] The establishment of the inverter power supply short-circuit current model in this application takes into account the current limiting characteristics of the inverter power supply itself and the low voltage ride-through requirements of the inverter power supply. It describes the short-circuit current output by the inverter power supply when a power grid fails more accurately and meticulously. The short-circuit current is solved by a cyclic iteration method, which is independent of a specific primary topology and a specific distributed power source. It is applicable to distribution networks of any given topology and has a wide range of applications.

[0151] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A method for determining short-circuit current in a distribution network, characterized in that: include: Calculating and processing the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages; A model is constructed based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply to obtain a short-circuit current calculation model of each stage corresponding to the same inverter power supply; Based on the target distribution network architecture, determining an admittance matrix of the target distribution network architecture, and constructing a node voltage equation of the target distribution network architecture based on the admittance matrix; Based on the rated current value corresponding to each of the inverter power supplies, the node voltage equation and the short-circuit current calculation model corresponding to each of the inverter power supplies are used to iteratively determine the short-circuit current of the distribution network to obtain the short-circuit current value corresponding to each of the inverter power supplies; The calculation and processing based on the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold for dividing the output current and grid connection point voltage of each inverter power supply into nonlinear relationship stages specifically includes: Constructing a model based on the rated voltage capacity parameters, the rated current capacity parameters and the predetermined standard of each of the inverter power supplies to obtain a reactive current calculation model corresponding to each of the inverter power supplies; Models are constructed based on the pre-fault output parameters and rated current capacity parameters of each of the inverter power supplies to obtain active current calculation models corresponding to each of the inverter power supplies; Based on the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply, a calculation process is performed to obtain a first boundary threshold used for dividing the output current and the grid connection point voltage of the same inverter power supply into nonlinear relationship stages, so as to obtain the first boundary threshold corresponding to each inverter power supply respectively; The model is constructed based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply to obtain the short-circuit current calculation model of each stage corresponding to the same inverter power supply, specifically including: For the same inverter power supply, when the ratio of the grid connection point voltage parameter to the voltage capacity parameter after the fault is greater than or equal to the predetermined second boundary threshold, a model is constructed based on the pre-fault output parameter of the same inverter power supply and the grid connection point voltage parameter after the fault, to obtain a first-stage short-circuit current calculation model corresponding to the same inverter power supply; When the ratio of the post-fault grid connection point voltage to the voltage capacity parameter is greater than the first boundary threshold and less than the predetermined second boundary threshold, a model is constructed based on the pre-fault output parameter, the post-fault grid connection point voltage parameter, the rated voltage capacity parameter and the rated output parameter of the same inverter power supply to obtain a second-stage short-circuit current calculation model corresponding to the same inverter power supply; When the ratio of the grid connection point voltage to the rated voltage capacity parameter after the fault is less than the first boundary threshold, a model is constructed based on the rated output parameter and the rated voltage capacity parameter of the same inverter power supply to obtain a third-stage short-circuit current calculation model corresponding to the same inverter power supply.

2. The method according to claim 1, characterized in that The determining, based on the target distribution network architecture, an admittance matrix of the target distribution network architecture specifically includes: A target distribution network architecture based on the short-circuit current to be determined is modeled using the Norton equivalent method to obtain a fault equivalent network model corresponding to the target distribution network architecture, wherein the fault equivalent network model includes: a system voltage source, at least one voltage-controlled current source, and a plurality of admittances; An admittance matrix is ​​constructed based on the fault equivalent network model to obtain the admittance matrix corresponding to the fault equivalent network model.

3. The method according to claim 1, characterized in that The step of determining the short-circuit current of the distribution network based on the rated current value corresponding to each of the inverter power supplies by using the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies to obtain the short-circuit current value corresponding to each of the inverter power supplies specifically includes: Performing calculation based on the rated current value corresponding to each of the inverter power supplies and a predetermined multiple to obtain an initial short-circuit current value corresponding to each of the inverter power supplies; Based on the initial values ​​of the short-circuit currents, the node voltage equation and the short-circuit current calculation models corresponding to the inverter power supplies are used to perform a corrected current calculation process in a cyclic iteration to obtain the short-circuit current value corresponding to the inverter power supply.

4. The method according to claim 3, characterized in that The method of performing a correction current calculation process based on each of the initial short-circuit current values ​​by using the node voltage equation and each of the short-circuit current calculation models corresponding to each of the inverter power supplies to obtain a short-circuit current value corresponding to each of the inverter power supplies specifically includes: Based on the initial value of the short-circuit current corresponding to each of the inverter power supplies, the node voltage equation is used to perform calculation processing to obtain the initial node voltage value corresponding to each of the inverter power supplies; Based on the initial node voltage value corresponding to the same inverter power supply, a short-circuit current calculation model corresponding to the same inverter power supply is used to perform correction calculation processing to obtain an initial correction current value of the first iteration round corresponding to the same inverter power supply; Performing a subtraction operation based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain an initial difference value; Performing absolute value calculation processing based on each of the initial differences to obtain a first absolute voltage value corresponding to each of the inverter power supplies; Screening each of the first absolute voltage values ​​to obtain a first target absolute voltage value; When the first target absolute voltage value is less than a preset threshold, each of the initial correction current values ​​is determined as a short-circuit current value corresponding to each of the inverter power supplies; When the first target absolute voltage value is greater than or equal to a preset threshold value, the short-circuit current initial value is updated based on each of the initial corrected current values, and the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies are used based on the updated initial short-circuit current values ​​to perform the corrected current calculation process for the next iteration round, and the process is iterated in a loop until the current node voltage values ​​of the current iteration round and the intermediate node voltage values ​​of the previous round meet the preset conditions, and the current corrected current value corresponding to the same inverter power supply of the current iteration round is determined as the short-circuit current value corresponding to the same inverter power supply.

5. The method according to claim 4, characterized in that The method of performing correction calculation based on the initial node voltage value corresponding to the same inverter power supply using the short-circuit current calculation model corresponding to the same inverter power supply to obtain the initial correction current value of the first iteration round corresponding to the same inverter power supply specifically includes: Calculating and processing based on the initial node voltage value and the rated voltage value corresponding to the same inverter power supply to obtain a first voltage ratio; Performing stage screening based on the first voltage ratio, the first boundary threshold, and the predetermined second boundary threshold to obtain a target stage corresponding to the first voltage ratio; Based on the initial node voltage value, the rated voltage value and the first voltage ratio, a target short-circuit current calculation model corresponding to the target stage is used to perform calculation processing to obtain an initial corrected current value of the first iteration round corresponding to the same inverter power supply.

6. A device for determining short-circuit current in a distribution network, characterized in that: include: A calculation module, used for performing calculation processing based on the output parameters and capacity parameters of each inverter power supply in the target distribution network architecture to obtain a first boundary threshold value for dividing the output current and the grid connection point voltage of each inverter power supply into nonlinear relationship stages; specifically comprising: constructing a model based on the rated voltage capacity parameters, rated current capacity parameters and predetermined standards of each inverter power supply to obtain a reactive current calculation model corresponding to each inverter power supply; constructing a model based on the pre-fault output parameters and rated current capacity parameters of each inverter power supply to obtain an active current calculation model corresponding to each inverter power supply; performing calculation processing based on the reactive current calculation model and the active current calculation model corresponding to the same inverter power supply to obtain a first boundary threshold value for dividing the output current and the grid connection point voltage of the same inverter power supply into nonlinear relationship stages, so as to obtain the first boundary threshold value corresponding to each inverter power supply respectively; The model building module is used to build a model based on the first boundary threshold, the capacity parameter and the predetermined second boundary threshold corresponding to the same inverter power supply, and obtain the short-circuit current calculation model of each stage corresponding to the same inverter power supply; specifically comprising: for the same inverter power supply, when the ratio of the grid connection point voltage parameter to the voltage capacity parameter after the fault is greater than or equal to the predetermined second boundary threshold, the model is built based on the output parameter before the fault of the same inverter power supply and the grid connection point voltage parameter after the fault, and the first stage short-circuit current calculation model corresponding to the same inverter power supply is obtained; when the grid connection point voltage after the fault is greater than or equal to the predetermined second boundary threshold, the model is built based on the output parameter before the fault of the same inverter power supply and the grid connection point voltage parameter after the fault, and the first stage short-circuit current calculation model corresponding to the same inverter power supply is obtained; when the grid connection point voltage after the fault is greater than the voltage capacity parameter When the ratio of the grid connection point voltage to the rated voltage capacity parameter after the fault is less than the first boundary threshold, the model is constructed based on the pre-fault output parameter, the post-fault grid connection point voltage parameter, the rated voltage capacity parameter and the rated output parameter of the same inverter power supply to obtain a second-stage short-circuit current calculation model corresponding to the same inverter power supply; when the ratio of the post-fault grid connection point voltage to the rated voltage capacity parameter is less than the first boundary threshold, the model is constructed based on the rated output parameter and the rated voltage capacity parameter of the same inverter power supply to obtain a third-stage short-circuit current calculation model corresponding to the same inverter power supply; A node power supply equation construction module, used to determine the admittance matrix of the target distribution network architecture based on the target distribution network architecture, and to construct a node voltage equation of the target distribution network architecture based on the admittance matrix; A determination module is used to determine the short-circuit current of the distribution network based on the rated current value corresponding to each of the inverter power supplies by using the node voltage equation and the short-circuit current calculation models corresponding to each of the inverter power supplies to iteratively obtain the short-circuit current value corresponding to each of the inverter power supplies.

7. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for determining the short-circuit current of the distribution network described in any one of claims 1 to 5 are implemented.

8. An electronic device, characterized in that: The method comprises at least a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method for determining the short-circuit current of the distribution network as described in any one of claims 1 to 5 when executing the computer program on the memory.

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