New energy station grid-connected point impedance calculation method, electronic equipment and storage medium

Abstract

The embodiment of the invention relates to the technical field of stations, and discloses a new energy station grid-connected point impedance calculation method, electronic equipment and a storage medium, and the new energy station grid-connected point impedance calculation method comprises the steps: inputting a disturbance current at a grid-connected point in a station topology, constructing a frequency domain model under the disturbance frequency and a frequency domain model under the coupling frequency; generating a first admittance matrix according to the frequency domain model under the disturbance frequency, and generating a second admittance matrix according to the frequency domain model under the coupling frequency; and combining the first admittance matrix and the second admittance matrix to obtain a combined matrix, extracting admittance data of the grid-connected point from the combined matrix, and obtaining impedance data of the grid-connected point according to the admittance data of the grid-connected point. According to the embodiment, more complete and accurate grid-connected point impedance data can be obtained, refined time domain simulation does not need to be carried out on the station, the accuracy of obtaining the grid-connected point impedance can be improved, and the input cost of simulation and the accuracy of obtaining the grid-connected point impedance are both considered.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of station technology, and in particular to a method for calculating the impedance of a grid connection point of a new energy station, an electronic device, and a storage medium. Background Art

[0002] At present, with the rapid development of a high proportion of renewable energy and a high proportion of power electronic equipment in the power grid, the problem of small disturbance instability caused by oscillation in the new power system with new energy as the main body is becoming increasingly prominent. Oscillation accidents with subsynchronous, supersynchronous and medium and high frequencies frequently occur in fields such as new energy stations and flexible direct current transmission, seriously affecting the reliable absorption of new energy and the safe and stable operation of the new power system.

[0003] However, the accuracy of current frequency domain stability analysis of systems containing new energy devices is still relatively low. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a method for calculating the grid connection point impedance of a new energy station, an electronic device, and a storage medium, thereby taking into account both the investment cost of the simulation and the accuracy of obtaining the grid connection point impedance.

[0005] To solve the above technical problems, an embodiment of the present application provides a method for calculating the impedance of a grid-connected point of a new energy station, including: inputting a disturbance current at the grid-connected point in the station topology to construct a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency; generating a first admittance matrix according to the frequency domain model at the disturbance frequency, the first admittance matrix representing the admittance matrix relationship between the node voltage and the power supply current of the station topology at the disturbance frequency; generating a second admittance matrix according to the frequency domain model at the coupling frequency, the second admittance matrix representing the admittance matrix relationship between the node voltage and the power supply current of the station topology at the coupling frequency; combining the first admittance matrix and the second admittance matrix to obtain a joint matrix; extracting the admittance data of the grid-connected point from the joint matrix, the admittance data of the grid-connected point including the relationship between the voltage of the grid-connected point at the disturbance frequency and the disturbance current, and the relationship between the voltage of the grid-connected point at the coupling frequency and the disturbance current; obtaining the impedance data of the grid-connected point according to the admittance data of the grid-connected point.

[0006] An embodiment of the present application also provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the above-mentioned method for calculating the grid connection point impedance of a new energy station.

[0007] An embodiment of the present application further provides a computer storage medium, comprising: storing a computer program, characterized in that when the computer program is executed by a processor, it implements the above-mentioned method for calculating the impedance of the grid connection point of a new energy station.

[0008] In some embodiments, the site topology includes equivalent circuits of a plurality of the electrical devices.

[0009] In some embodiments, before the disturbance current is input to the grid connection point in the station topology, it also includes: when the electrical equipment is a new energy equipment, obtaining the actual operating condition data of the electrical equipment; the operating condition data includes the port voltage amplitude phase and the port current amplitude phase; obtaining the impedance data corresponding to the operating condition data, so as to apply the impedance data corresponding to the operating condition data to the equivalent circuit corresponding to the station topology.

[0010] In some embodiments, the method further includes: when the electrical equipment is not the new energy equipment, obtaining the admittance data of the electrical equipment by means of mechanism modeling; obtaining the impedance data of the electrical equipment based on the admittance data of the electrical equipment, so as to apply the impedance data of the electrical equipment to the equivalent circuit corresponding to the site topology.

[0011] In some embodiments, before obtaining the impedance data corresponding to the operating condition data, it also includes: obtaining the target impedance data of the new energy equipment under multiple operating conditions; constructing an impedance database based on the target impedance data under multiple operating conditions; storing the impedance database when the impedance database is less than or equal to a preset threshold; generating an impedance identification model based on the impedance database when the impedance database is greater than the preset threshold; obtaining the impedance data corresponding to the operating condition data includes: when the impedance database is less than or equal to the preset threshold, using an interpolation method on the impedance database to obtain the impedance data corresponding to the operating condition data; when the impedance database is greater than the preset threshold, using the impedance identification model to obtain the impedance data corresponding to the operating condition data.

[0012] In some embodiments, the acquiring of the target impedance data of the new energy equipment under a plurality of working conditions includes: for each working condition, injecting positive-sequence disturbance and negative-sequence disturbance into the new energy equipment respectively to acquire the impedance data of the positive-sequence coupling frequency and the impedance data of the negative-sequence coupling frequency of the new energy equipment; the target impedance data includes the impedance data of the positive-sequence coupling frequency and the impedance data of the negative-sequence coupling frequency; wherein, if the new energy equipment includes a grid-following inverter, the positive-sequence voltage disturbance and the negative-sequence voltage disturbance are respectively injected into the new energy equipment; if the new energy equipment includes a grid-forming inverter, the positive-sequence current disturbance and the negative-sequence current disturbance are respectively injected into the new energy equipment.

[0013] In some embodiments, the disturbance current is input at the grid connection point in the station topology to construct a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency, including: inputting a positive-sequence disturbance current at the grid connection point in the station topology to construct a frequency domain model at the positive-sequence disturbance frequency and a frequency domain model at the positive-sequence coupling frequency; or, inputting a negative-sequence disturbance current at the grid connection point in the station topology to construct a frequency domain model at the negative-sequence disturbance frequency and a frequency domain model at the negative-sequence coupling frequency.

[0014] In some embodiments, obtaining the actual operating condition data of the electrical equipment includes: obtaining the actual operating condition data of the new energy equipment based on power flow calculation.

[0015] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0016] This embodiment constructs a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency, generates a first admittance matrix according to the frequency domain model at the disturbance frequency, generates a second admittance matrix according to the frequency domain model at the coupling frequency, combines the first admittance matrix and the second admittance matrix to obtain a joint matrix, extracts the admittance data of the grid connection point from the joint matrix, and obtains the impedance data of the grid connection point according to the admittance data of the grid connection point, so that the obtained impedance data includes the impedance at the disturbance frequency and the impedance at the coupling frequency, and more complete and accurate impedance data can be obtained. Without the need for refined time domain simulation of the site, the accuracy of obtaining the grid connection point impedance can also be improved, taking into account both the investment cost of the simulation and the accuracy of obtaining the grid connection point impedance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] As can be seen from the background technology, the accuracy of the current frequency domain stability analysis of systems containing new energy equipment is still relatively low.

[0018] Through analysis and research, we found that due to the frequency coupling of the impedance of new energy equipment, if the impact of frequency coupling on the frequency domain stability of new energy equipment is not considered, the impedance-based frequency domain stability analysis of the system containing new energy equipment will not accurately determine the system stability and cannot effectively obtain the system oscillation information. Therefore, in order to better improve the stability of the system containing new energy stations, it is necessary to calculate the complete impedance of the grid connection point of the new energy station taking into account frequency coupling.

[0019] In order to solve the above-mentioned technical problems, the present application provides a method for calculating the impedance of the grid connection point of a new energy station, wherein a disturbance current is input into the grid connection point in the station topology to construct a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency; a first admittance matrix is generated according to the frequency domain model, and the first admittance matrix represents the admittance matrix relationship between the node voltage and the power supply current of the station topology at the disturbance frequency; a second admittance matrix is generated according to the frequency domain model, and the second admittance matrix represents the admittance matrix relationship between the node voltage and the power supply current of the station topology at the coupling frequency; the first admittance matrix and the second admittance matrix are combined to obtain a joint matrix; the admittance data of the grid connection point is extracted from the joint matrix, and the admittance data of the grid connection point includes the relationship between the voltage and the disturbance current of the grid connection point at the disturbance frequency, and the relationship between the voltage and the disturbance current of the grid connection point at the coupling frequency; and the impedance data of the grid connection point is obtained according to the admittance data of the grid connection point. The impedance data obtained includes the impedance at the disturbance frequency and the impedance at the coupling frequency, which can obtain more complete and accurate impedance data. There is no need to perform refined time domain simulation on the site, and the accuracy of obtaining the grid connection point impedance can be improved, taking into account the investment cost of the simulation and the accuracy of the grid connection point impedance acquisition.

[0020] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1 1 is a flow chart of a method for calculating the impedance of a new energy station grid connection point according to an embodiment of the present application;

[0022] Figure 2 is an equivalent schematic diagram of a site topology according to an embodiment of the present application;

[0023] Figure 3 1 is a flow chart of a method for calculating the impedance of a new energy station grid connection point according to another embodiment of the present application;

[0024] Figure 4 This is a flow chart of obtaining impedance data corresponding to operating condition data according to an embodiment of the present application;

[0025] Figure 5 2 is a schematic structural diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below with reference to the accompanying drawings. However, it will be understood by those skilled in the art that in each embodiment of the present application, many technical details are proposed to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be implemented. The division of the following embodiments is for convenience of description and should not constitute any limitation on the specific implementation of the present application. The various embodiments can be combined and referenced with each other under the premise of no contradiction.

[0027] An embodiment of the present application relates to a method for calculating the impedance of a new energy station grid connection point. The specific flow chart is as follows: Figure 1 As shown in FIG, the impedance calculation method of the grid connection point of a new energy station includes the following steps:

[0028] Step 101: input a disturbance current at a grid connection point in a station topology to construct a frequency domain model at a disturbance frequency and a frequency domain model at a coupling frequency.

[0029] Specifically, an actual station includes multiple electrical equipment, which may include new energy equipment and other equipment in addition to new energy equipment. Therefore, the station topology includes the equivalent circuits of multiple electrical equipment. The station topology may include the equivalent circuits of new energy equipment and other equipment in addition to new energy equipment.

[0030] Specifically, new energy equipment includes new energy equipment including grid-following inverters and new energy equipment including grid-building inverters. New energy equipment including grid-following inverters exhibits current source characteristics, so the new energy equipment including grid-following inverters passes through the Norton equivalence, and the equivalent circuit is in the form of a controlled current source in parallel with an impedance. New energy equipment including grid-building inverters exhibits voltage source characteristics, so the new energy equipment including grid-building inverters passes through the Thevenin equivalence, and the equivalent circuit is in the form of a controlled voltage source in series with an impedance.

[0031] like Figure 2As shown in FIG, an equivalent schematic diagram of the site topology of this embodiment, wherein 10a is a new energy device containing a grid-type inverter, and 10b is a new energy device containing a grid-following inverter. Multiple new energy devices 10a containing grid-type inverters and new energy devices 10b containing grid-following inverters are all connected to the grid connection point, i.e., the point of common coupling (PCC), through the line Line. By injecting a disturbance signal at the PPC point, a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency can be constructed.

[0032] In some embodiments, a disturbance current is input at the grid connection point in the station topology to construct a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency, including: inputting a positive-sequence disturbance current at the grid connection point in the station topology to construct a frequency domain model at the positive-sequence disturbance frequency and a frequency domain model at the positive-sequence coupling frequency; or, inputting a negative-sequence disturbance current at the grid connection point in the station topology to construct a frequency domain model at the negative-sequence disturbance frequency and a frequency domain model at the negative-sequence coupling frequency.

[0033] Specifically, the station topology has a grid connection point, namely the PCC point. According to the station topology, if the positive-sequence impedance of the PCC point is calculated, a frequency domain model at the positive-sequence disturbance frequency and a frequency domain model at the positive-sequence coupling frequency are constructed respectively, and the positive-sequence coupling frequency is the positive-sequence disturbance frequency minus twice the fundamental frequency; if the negative-sequence impedance of the PCC point is calculated, a frequency domain model at the negative-sequence disturbance frequency and a frequency domain model at the negative-sequence coupling frequency are constructed respectively, and the negative-sequence coupling frequency is the negative-sequence disturbance frequency plus twice the fundamental frequency.

[0034] Specifically, the frequency domain model is constructed by injecting disturbance signals and measuring the responses, including the impedance characteristics of the positive and negative sequences.

[0035] Inject a positive sequence current disturbance at the PCC point with a frequency of f p At this time, the response current and voltage of the electrical equipment in the station topology can be represented by the frequency domain model at the positive sequence disturbance frequency. Due to the frequency coupling effect, the positive sequence disturbance will generate a frequency f in the station topology. p The negative sequence component of -2f1, where f1 is the fundamental frequency, can be 50Hz or 60Hz. Therefore, a frequency domain model at the positive sequence coupling frequency needs to be constructed to describe this coupling effect.

[0036] Inject negative sequence current disturbance at PCC point with frequency f n At this time, the response current and voltage of the electrical equipment in the station topology can be represented by the frequency domain model at the negative sequence disturbance frequency. Due to the frequency coupling effect, the negative sequence disturbance will generate a frequency f in the system. n +2f1 is the positive sequence component, so it is necessary to construct a frequency domain model at the negative sequence coupling frequency to describe this coupling effect.

[0037] Specifically, the positive sequence coupling frequency is generated because: for the positive sequence disturbance frequency f p , the coupling frequency is f p -2f1, this coupling effect is due to the frequency offset caused by the phase-locked loop or control strategy; the reason for the negative sequence coupling frequency is: for the negative sequence disturbance frequency f n , the coupling frequency is f n +2f1, this coupling effect also originates from the control strategy or system dynamics.

[0038] Step 102 : generating a first admittance matrix according to a frequency domain model at a disturbance frequency; and generating a second admittance matrix according to a frequency domain model at a coupling frequency.

[0039] Specifically, the first admittance matrix represents the admittance matrix relationship between the node voltage and the power supply current of the station topology at the disturbance frequency; the second admittance matrix represents the admittance matrix relationship between the node voltage and the power supply current of the station topology at the coupling frequency.

[0040] Step 103: Combine the first admittance matrix and the second admittance matrix to obtain a combined matrix.

[0041] Specifically, a first admittance matrix is generated for the frequency-domain model at the perturbation frequency to obtain the relationship between the node voltage and the power supply current at the perturbation frequency. A second admittance matrix is generated for the frequency-domain model at the coupling frequency to obtain the relationship between the node voltage and the power supply current at the coupling frequency. Because the impedance of new energy devices is frequency-coupled, the admittance matrices at these two frequencies are coupled. Therefore, the two admittance matrices are combined to obtain a new matrix, the joint matrix, which is then solved.

[0042] Specifically, the frequency domain model at the perturbation frequency is a frequency domain model of the device constructed at a specific perturbation frequency. The frequency domain model at the perturbation frequency can be used to generate a first admittance matrix, which represents the admittance matrix relationship between the voltage of the device node and the power supply current at the perturbation frequency. The frequency domain model at the coupling frequency is another frequency domain model constructed at the coupling frequency. The frequency domain model at the coupling frequency can be used to generate a second admittance matrix, which represents the relationship between the voltage of the device node and the power supply current at the coupling frequency.

[0043] Specifically, there is frequency coupling in the dynamic model of new energy equipment, that is, the small signal injection at the disturbance frequency will affect the response description at the coupling frequency, and the small signal injection at the coupling frequency will also affect the response description at the disturbance frequency. Therefore, the admittance matrices at these two frequencies are not independent, but there is a coupling relationship in which they influence each other.

[0044] Specifically, in order to take this coupling relationship into account, it is necessary to combine the first admittance matrix and the second admittance matrix to form a new joint matrix. The joint matrix contains the admittance information at both the disturbance frequency and the coupling frequency. By solving this joint matrix, the comprehensive relationship between the node voltage and the power supply current of the device at the two frequencies can be obtained, thereby more accurately describing the dynamic characteristics of the device.

[0045] Step 104: extract the admittance data of the grid connection point from the joint matrix.

[0046] Step 105 : Obtain impedance data of the grid connection point according to the admittance data of the grid connection point.

[0047] Specifically, the admittance data of the grid connection point includes the relationship between the voltage and the disturbance current of the grid connection point at the disturbance frequency, and the relationship between the voltage and the disturbance current of the grid connection point at the coupling frequency.

[0048] Specifically, because the injected disturbance current only exists at the disturbance frequency and the disturbance current is only injected at the PCC point, but the generated voltage response exists at the disturbance frequency and the coupling frequency, the joint matrix obtained above is simplified and transformed to extract the admittance data of the PCC point, that is, the relationship between the disturbance frequency voltage and coupling frequency voltage of the PCC point and the disturbance current.

[0049] Taking the positive sequence as an example, the admittance data of the PCC point is shown as follows:

[0050]

[0051] in,

[0052] s1=j2πf1, f1 is the system base frequency, V pcc (s)) is the voltage at the PCC point at the disturbance frequency, V pcc (s-2s1) is the voltage at the PCC point at the coupling frequency; I pcc (s) is the injected current at the PCC point at the positive sequence disturbance frequency; Z p is the positive sequence impedance matrix.

[0053] Let Z p11 , Z p12 , Z p21 , Z p22 Z p The upper left corner element, upper right corner element, lower left corner element, and lower right corner element of the matrix can be obtained as follows:

[0054]

[0055] The calculation formulas for impedance, voltage and current are as follows:

[0056] Vpcc (s)=Z p11 I pcc (s)

[0057] V pcc (s-2s1)=Z p21 I pcc (s)

[0058] From this we can get Z in the station impedance matrix p11 is the positive sequence self-impedance, Z p21 is the positive sequence coupling impedance, and similarly the negative sequence self impedance and negative sequence coupling impedance are obtained.

[0059] This embodiment constructs a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency, generates a first admittance matrix according to the frequency domain model at the disturbance frequency, generates a second admittance matrix according to the frequency domain model at the coupling frequency, combines the first admittance matrix and the second admittance matrix to obtain a joint matrix, extracts the admittance data of the grid connection point from the joint matrix, and obtains the impedance data of the grid connection point according to the admittance data of the grid connection point, so that the obtained impedance data includes the impedance at the disturbance frequency and the impedance at the coupling frequency, and more complete and accurate impedance data can be obtained. Without the need for refined time domain simulation of the site, the accuracy of obtaining the grid connection point impedance can also be improved, taking into account both the investment cost of the simulation and the accuracy of obtaining the grid connection point impedance.

[0060] On the other hand, this application also provides a method for calculating the impedance of a new energy station grid connection point. The specific flow chart is as follows: Figure 3 As shown in FIG, the impedance calculation method of the grid connection point of a new energy station includes the following steps:

[0061] This embodiment further includes the following steps before the disturbance current is input to the grid connection point in the station topology:

[0062] Step 201: Determine whether the electrical equipment is a new energy equipment.

[0063] If yes, go to step 202 ; if no, go to step 204 .

[0064] Step 202: Acquire actual operating condition data of the electrical equipment.

[0065] Specifically, the operating condition data includes the port voltage amplitude and phase, and the port current amplitude and phase.

[0066] Step 203: Obtain impedance data corresponding to the operating condition data, so as to apply the impedance data corresponding to the operating condition data to the equivalent circuit corresponding to the station topology. After step 203, the process proceeds to step 206.

[0067] Specifically, this embodiment obtains operating condition data of electrical equipment, namely, new energy equipment, based on power flow calculation.

[0068] In some embodiments, before step 202, i.e., obtaining impedance data corresponding to the operating condition data, the method further includes: obtaining target impedance data of the new energy equipment under multiple operating conditions; constructing an impedance database based on the target impedance data under multiple operating conditions; storing the impedance database when the impedance database is less than or equal to a preset threshold; generating an impedance identification model based on the impedance database when the impedance database is greater than the preset threshold; obtaining impedance data corresponding to the operating condition data, including: obtaining impedance data corresponding to the operating condition data using an interpolation method on the impedance database when the impedance database is less than or equal to the preset threshold; and obtaining impedance data corresponding to the operating condition data using the impedance identification model when the impedance database is greater than the preset threshold.

[0069] Obtain target impedance data of new energy equipment under various operating conditions, including: for each operating condition, injecting positive-sequence disturbance and negative-sequence disturbance into the new energy equipment respectively to obtain impedance data of the new energy equipment at the positive-sequence coupling frequency and impedance data at the negative-sequence coupling frequency; the target impedance data includes impedance data at the positive-sequence coupling frequency and impedance data at the negative-sequence coupling frequency; among them, if the new energy equipment includes a grid-following inverter, injecting positive-sequence voltage disturbance and negative-sequence voltage disturbance into the new energy equipment respectively; if the new energy equipment includes a grid-forming inverter, injecting positive-sequence current disturbance and negative-sequence current disturbance into the new energy equipment respectively.

[0070] like Figure 4 FIG. 1 is a flow chart showing how to obtain impedance data corresponding to operating condition data according to this embodiment, including the following steps:

[0071] S1, multi-condition impedance scan.

[0072] Impedance scanning is the impedance measurement of new energy equipment under various operating conditions. These conditions may include different load conditions, grid voltage levels, power factors, etc. By measuring under various conditions, the impedance characteristics of the equipment under different operating conditions are obtained, thereby building a comprehensive impedance database.

[0073] S2, build the device impedance database.

[0074] The measured impedance data are stored in a database, which includes impedance values (such as resistance and reactance) and frequency characteristics under different working conditions, for subsequent analysis and application.

[0075] S3, flow calculation to obtain working conditions.

[0076] The electrical parameters of new energy equipment in actual operation are obtained through grid flow calculation (such as power system flow analysis), including: port voltage amplitude and phase, port current amplitude and phase. These data are used to determine the actual operating conditions of the equipment, making it easier to obtain the corresponding impedance data from the impedance database.

[0077] S4, database size.

[0078] If the database scale is small, go to S5; if the database scale is large, go to S6.

[0079] S5, working condition interpolation, then enter S9.

[0080] When the impedance database is small, the impedance data of the equipment under actual operating conditions is directly obtained from the database through interpolation (such as linear interpolation and polynomial interpolation). At this time, even if the measurement data is directly stored, the storage space occupied by the database is small, which is suitable for the case where the database is small.

[0081] S6, Neural Network Learning.

[0082] S7, obtaining an impedance identification model.

[0083] S8: Impedance identification. Then enter S9.

[0084] When the impedance database is large, an impedance identification model is constructed using impedance identification methods (such as system identification or machine learning algorithms). This model is then used to predict the impedance data of the equipment under actual operating conditions. In this case, only the impedance identification model needs to be stored, eliminating the need for storing large amounts of raw data. This saves storage space and allows the model to more flexibly handle complex operating conditions, improving prediction accuracy.

[0085] S9, obtain impedance data.

[0086] Specifically, this embodiment first performs impedance scanning of each electrical device under multiple working conditions, and constructs an impedance database with the acquired impedance data. According to the power flow calculation, the port voltage amplitude phase, port current amplitude phase and other data of the new energy equipment in the station are obtained to determine the operating conditions of the equipment. The impedance data under the actual operating conditions of the equipment can be obtained by interpolation or impedance identification methods. When the impedance database is small, it is recommended to use the interpolation method to obtain the impedance data, in which case the storage space occupied by the database is small; when the impedance database is large, it is recommended to use the impedance identification method to obtain the impedance data. In this case, it is only necessary to store the impedance identification model without storing the impedance database, which can save a lot of storage space.

[0087] Step 204: Acquire the admittance data of the electrical equipment using a mechanism modeling approach.

[0088] In step 205 , the impedance data of the electrical device is obtained based on the admittance data of the electrical device, so as to apply the impedance data of the electrical device to the equivalent circuit corresponding to the station topology.

[0089] For electrical equipment such as transformers and lines that are not new energy equipment, the admittance data is calculated using mechanism modeling. Considering them as two-port devices, the two-port expression for each device can be derived as follows:

[0090]

[0091] Where Y(s) is the equivalent two-port admittance matrix of the device. The relationship between the two-port admittance matrix Y(s) and the voltage and current is as follows:

[0092]

[0093] Among them, U1 is the left port voltage, I1 is the left injection current, U2 is the right port voltage, I2 is the right injection current, Y 11 、Y 12 、Y 21 、Y 22 They are the upper left corner element, upper right corner element, lower left corner element, and lower right corner element of the Y(s) matrix. By knowing U1, I1, U2, I2, we can calculate Y 11 、Y 12 、Y 21 、Y 22 , Y 11 、Y 12 、Y 21 、Y 22 Describes the self-admittance and mutual-admittance characteristics of the device at different ports respectively. 11 、Y 12 、Y 21 、Y 22 The impedance data of the device can be obtained.

[0094] Step 206 : Input the disturbance current at the grid connection point in the site topology to construct a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency.

[0095] Step 207 : Generate a first admittance matrix according to the frequency domain model at the disturbance frequency; and generate a second admittance matrix according to the frequency domain model at the coupling frequency.

[0096] Step 208: Combine the first admittance matrix and the second admittance matrix to obtain a combined matrix.

[0097] Step 209 : extracting the admittance data of the grid connection point from the joint matrix. The admittance data of the grid connection point includes the relationship between the voltage and the disturbance current at the grid connection point at the disturbance frequency, and the relationship between the voltage and the disturbance current at the grid connection point at the coupling frequency.

[0098] Step 210: Obtain impedance data of the grid connection point based on the admittance data of the grid connection point.

[0099] Steps 206 to 210 are substantially the same as steps 101 to 105 in the previous embodiment, and are not described again to avoid repetition.

[0100] An embodiment of the present application relates to an electronic device, such as Figure 5 As shown, it includes: at least one processor 301; and a memory 302 communicatively connected to the at least one processor 301; wherein the memory stores instructions that can be executed by the at least one processor 301, and the instructions are executed by the at least one processor 301 to enable the at least one processor 301 to execute the above-mentioned new energy station grid connection point impedance calculation method.

[0101] The memory 302 and processor 301 are connected using a bus. The bus can include any number of interconnected buses and bridges, connecting various circuits of one or more processors 301 and memory 302. The bus can also connect various other circuits such as peripheral devices, voltage regulators, and power management circuits. These are all well known in the art and are therefore not described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single component or multiple components, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor 301 is transmitted over a wireless medium via an antenna. Furthermore, the antenna receives data and transmits it to the processor 301.

[0102] The processor 301 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management and other control functions. The memory 302 can be used to store data used by the processor when performing operations.

[0103] An embodiment of the present application relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0104] That is, those skilled in the art will understand that all or part of the steps in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a program, which is stored in a storage medium and includes a number of instructions for causing a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps in the various embodiments of the present application. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc., various media that can store program code.

[0105] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A method for calculating the impedance of a new energy station grid connection point, characterized in that: include: Input the disturbance current at the grid connection point in the station topology to construct a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency; generating a first admittance matrix according to the frequency domain model at the disturbance frequency, wherein the first admittance matrix represents a node admittance matrix relationship between a node voltage and a power supply current of the station topology at the disturbance frequency; generating a second admittance matrix according to the frequency domain model at the coupling frequency, wherein the second admittance matrix represents a node admittance matrix relationship between a node voltage of the station topology at the coupling frequency and the power supply current; Combining the first admittance matrix and the second admittance matrix to obtain a combined matrix; Extracting the admittance data of the grid connection point from the joint matrix, the admittance data of the grid connection point including the relationship between the voltage of the grid connection point at the disturbance frequency and the disturbance current, and the relationship between the voltage of the grid connection point at the coupling frequency and the disturbance current; The impedance data of the grid connection point is obtained according to the admittance data of the grid connection point.

2. The method for calculating the impedance of the grid connection point of a new energy station according to claim 1, characterized in that: The site topology includes equivalent circuits of a plurality of the electrical devices.

3. The method for calculating the impedance of the grid connection point of a new energy station according to claim 2, characterized in that: Before the disturbance current is input to the grid connection point in the station topology, the method further includes: In the case where the electrical equipment is a new energy equipment, obtaining actual operating condition data of the electrical equipment; the operating condition data includes a port voltage amplitude phase and a port current amplitude phase; Impedance data corresponding to the operating condition data is acquired, so as to apply the impedance data corresponding to the operating condition data to an equivalent circuit corresponding to the station topology.

4. The method for calculating the impedance of the grid connection point of a new energy station according to claim 3 is characterized in that: The method further includes: when the electrical device is not the new energy device, acquiring the admittance data of the electrical device by adopting a mechanism modeling method; The impedance data of the electrical equipment is acquired according to the admittance data of the electrical equipment, so as to apply the impedance data of the electrical equipment to an equivalent circuit corresponding to the site topology.

5. The method for calculating the impedance of the grid connection point of a new energy station according to claim 3 is characterized in that: Before obtaining the impedance data corresponding to the operating condition data, the method further includes: Acquiring target impedance data of the new energy equipment under various working conditions; and constructing an impedance database based on the target impedance data under various working conditions; When the impedance database is less than or equal to a preset threshold, storing the impedance database; when the impedance database is greater than the preset threshold, generating an impedance identification model according to the impedance database; The obtaining of impedance data corresponding to the operating condition data includes: When the impedance database is less than or equal to a preset threshold, an interpolation method is used on the impedance database to obtain impedance data corresponding to the operating condition data; When the impedance database is greater than the preset threshold, the impedance data corresponding to the operating condition data is acquired using the impedance identification model.

6. The method for calculating the impedance of the grid connection point of a new energy station according to claim 5, characterized in that: The obtaining of target impedance data of the new energy equipment under various working conditions includes: For each operating condition, a positive-sequence disturbance and a negative-sequence disturbance are respectively injected into the new energy device to obtain impedance data of the new energy device at a positive-sequence coupling frequency and impedance data at a negative-sequence coupling frequency; the target impedance data includes the impedance data at the positive-sequence coupling frequency and the impedance data at the negative-sequence coupling frequency; Among them, if the new energy equipment includes a grid-following inverter, positive-sequence voltage disturbance and negative-sequence voltage disturbance are respectively injected into the new energy equipment; if the new energy equipment includes a grid-forming inverter, positive-sequence current disturbance and negative-sequence current disturbance are respectively injected into the new energy equipment.

7. The method for calculating the impedance of the grid connection point of a new energy station according to claim 1, characterized in that: The disturbance current is inputted at the grid connection point in the station topology to construct a frequency domain model at the disturbance frequency and a frequency domain model at the coupling frequency, including: A positive-sequence disturbance current is input at the grid-connected point in the station topology to construct a frequency domain model at the positive-sequence disturbance frequency and a frequency domain model at the positive-sequence coupling frequency; or a negative-sequence disturbance current is input at the grid-connected point in the station topology to construct a frequency domain model at the negative-sequence disturbance frequency and a frequency domain model at the negative-sequence coupling frequency.

8. The method for calculating the impedance of the grid connection point of a new energy station according to claim 3, characterized in that: The obtaining of actual operating condition data of the electrical equipment includes: The actual operating condition data of the new energy equipment is obtained according to the power flow calculation.

9. An electronic device, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the new energy station grid connection point impedance calculation method as described in any one of claims 1 to 8.

10. A computer storage medium, characterized in that include: A computer program is stored, wherein when the computer program is executed by a processor, the method for calculating the impedance of the grid connection point of a new energy station according to any one of claims 1 to 8 is implemented.

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