Industrial park complex frequency domain admittance matrix modeling method based on vector fitting technology

Abstract

The invention provides an industrial park complex frequency domain admittance matrix modeling method based on a vector fitting technology. The method comprises the following steps that S101, real-time amplitude-frequency and phase-frequency characteristic curves of all new energy units in an industrial park grid-connected operation state are measured in a grid-connected point disturbance mode; s102, obtaining the number of peak values of the new energy unit, determining the order of the complex frequency domain impedance of the new energy unit, and then determining the order of vector fitting; s103, using a vector fitting technology to identify the complex frequency domain impedance model of each new energy unit segment by segment to obtain segment accurate parameter representation of the complex frequency domain impedance model; and S104, establishing a complex frequency domain admittance matrix of the industrial park based on the complex frequency domain impedance model of each new energy unit in combination with line topology information and line parameters in the industrial park. According to the method, the problems of'grey box 'and'black box' of the converter caused by manufacturer confidentiality are effectively solved, and a specific and accurate converter complex frequency domain admittance model is obtained to analyze the grid-connected stability of the converter.

Description

Technical Field

[0001] The present invention relates to the technical field of vector fitting, and in particular to a complex frequency domain admittance matrix modeling method for an industrial park based on the vector fitting technology. Background Art

[0002] The complex frequency domain admittance matrix is ​​often used to analyze the resonant stability problem of power systems. The determinant of the complex frequency domain admittance matrix is ​​solved at zero and the system stability is judged according to the positive and negative real part of the characteristic root. The parameters of traditional equipment such as conductors and transformers are easy to know, but the specific parameters of new energy power generation system equipment are difficult to know due to the confidentiality of the internal control structure and parameters of the equipment by the supplier, which brings difficulties to the establishment of the complex frequency domain admittance matrix.

[0003] At present, the methods for establishing the complex frequency domain admittance matrix include two strategies: directly establishing it according to the topological structure and establishing it according to the state space equation deduction. The direct establishment of the complex frequency domain admittance matrix is ​​based on the complex frequency domain admittance matrix construction theory when the system topology and various parameters are clear; the state space equation derivation method also requires clarifying the system parameters, constructing the state space equation in the time domain and then converting it into the complex frequency domain admittance matrix. However, both strategies currently need to be applied when the parameters and topological structure of each device in the system are clear. They are no longer applicable to new energy equipment when the internal control structure and parameters of the equipment are unclear. Summary of the invention

[0004] In view of this, an object of the present invention is to provide an industrial park complex frequency domain admittance matrix modeling method based on vector fitting technology, so as to solve or at least partially solve the above-mentioned problems existing in the prior art.

[0005] To achieve the above object, the present invention provides a method for modeling an industrial park complex frequency domain admittance matrix based on vector fitting technology, the method comprising the following steps: S101. Use the grid-connected point disturbance method to measure the real-time amplitude-frequency and phase-frequency characteristic curves of each new energy unit in the grid-connected operation state of the industrial park, and obtain the impedance amplitude and phase frequency points of each new energy unit; S102, based on the frequency points of the impedance amplitude and phase of each new energy unit, obtaining the peak number of each new energy unit, determining the order of the complex frequency domain impedance of the new energy unit according to the peak number of each new energy unit, and then determining the order of vector fitting; S103, based on the order of vector fitting, using vector fitting technology to segmentally identify the complex frequency domain impedance model of each new energy unit, and obtain segmented accurate parameters of the complex frequency domain impedance model; S104. Based on the complex frequency domain impedance model of each new energy unit, combined with the line topology information and line parameters in the industrial park, a complex frequency domain admittance matrix of the industrial park is established.

[0006] Furthermore, the step S101 specifically includes the following steps: S11. Collect the three-phase voltage and current operation data of each new energy unit, use a feedforward neural network to fit the three-phase voltage and current operation data of each new energy unit, and establish a digital twin model; S12. Apply disturbance frequencies of different frequency points to each renewable energy unit at the grid connection point The small signal voltage disturbance is is the frequency, For the frequency points; S13. Calculate the difference between the digital twin model and the grid-connected current of each renewable energy unit after the small signal voltage disturbance to obtain the small signal current response, and perform Fourier analysis on it to obtain the current response of each renewable energy unit under the voltage disturbance in the complex frequency domain, which is expressed as follows:

[0007] in, is the frequency domain signal, For discrete Fourier analysis, is the function for Fourier analysis, i.e., the small signal current response, is the sampling point number, is the number of sampling points, is the natural logarithm, is an imaginary unit, is a natural number; S14. Calculate the disturbance frequency based on Fourier analysis results The ratio of the small signal current response and the small signal voltage disturbance intensity at , and the corresponding complex frequency domain impedance ; S15. Modify the disturbance frequency , and obtain the amplitude-frequency and phase-frequency characteristic curves of the impedance Z of the new energy unit; S16. When each new energy unit is running, inject small signal voltage disturbance in real time to obtain complex frequency domain impedance , and according to the complex frequency domain impedance The data is used to determine whether to update the impedance Z of the new energy unit.

[0008] Furthermore, the step S102 includes: drawing a Bode diagram for each frequency point obtained in step S101, and determining the order of fitting to be selected according to the number of peaks of the Bode diagram. .

[0009] Furthermore, the step S103 specifically includes the following steps: S31, segmenting the transfer function of the complex frequency domain impedance of each new energy unit; S32. Definition The transfer function form of the complex frequency domain impedance of the new energy unit in the frequency band is used, and vector fitting is performed based on the transfer function form of the complex frequency domain impedance of the new energy unit, which is expressed as follows:

[0010] in, is the transfer function of the complex frequency domain impedance of the new energy unit, is the order of each segment in the piecewise fitting, For the A point, , , , are the parameters to be determined through vector fitting, is the independent variable; S33, based on the vector fitting results, integration The transfer function of the complex frequency domain impedance of the new energy unit in each frequency band is obtained, and the piecewise transfer function of the complex frequency domain impedance of the new energy unit is obtained as follows: , which is expressed as follows:

[0011] in, , They are the first and second segments after vector fitting. The transfer function of the segment, is the transfer function of the complex frequency domain impedance of the new energy unit, is the frequency, and is the complex frequency domain impedance Bode plot and The frequency corresponding to the peak value; S34. In the case of no segmentation, repeat step S32 to obtain the entire segment transfer function of the complex frequency domain impedance of the new energy unit: , weight the piecewise transfer function and the whole-segment transfer function, and obtain the final transfer function of the complex frequency domain impedance of each new energy unit: , which is expressed as follows:

[0012] in, and are weight coefficients respectively.

[0013] Furthermore, the vector fitting is performed based on the transfer function form of the complex frequency domain impedance of the new energy unit, specifically including the following steps: S3.1, uniformly select from the fitting frequency band N Initial Pole , define an unknown function , which satisfies the multiplication of the fitting transfer function with have the same poles, expressed as follows:

[0014] in, To fit the transfer function, for The conjugate value of S3.2, the frequency points in step S101 are brought in to solve the vector fitting linear equations formula, which is expressed as follows:

[0015]

[0016]

[0017]

[0018] in, is the coefficient matrix in the vector fitting algorithm, is the number of frequency sampling points, is the unknown vector of the vector fitting equation, is the right-hand side term of the vector fitting algorithm, is a complex frequency variable, is the frequency response value of the objective function, For the The residual of the extreme point, For the The conjugate value of the residual at the extreme point, To perform a transpose operation on a matrix; S3.3. Based on steps S3.1 and S3.2, the fitting transfer function is obtained, which is expressed as follows:

[0019] in, To fit the transfer function, and They are and The zero point, Zero point To fit the poles of the transfer function, we can obtain ; S3.4. Repeat the calculation process of steps S3.2-S3.3 to gradually obtain more accurate vector fitting results.

[0020] Furthermore, the complex frequency domain admittance matrix of the industrial park includes: According to the topological structure of the industrial park, multiple nodes are established, and the diagonal elements of each node is the algebraic sum of the complex frequency domain admittances of all components connected to the node; Off-Diagonal Elements Represents the negative value of the complex frequency domain admittance between two nodes; The elements of the complex frequency domain admittance matrix are symmetric about the main diagonal, that is, = .

[0021] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes a complex frequency domain admittance matrix modeling method for an industrial park based on vector fitting technology. By measuring the real-time amplitude-frequency and phase-frequency characteristic curves of each new energy unit in the grid-connected operation state of the industrial park, the order of the complex frequency domain impedance of the new energy unit is determined, and then the order of vector fitting is determined. The complex frequency domain impedance model of each new energy unit is segmentedly identified using vector fitting technology, and the complex frequency domain admittance matrix of the industrial park is established, which effectively solves the "gray box" and "black box" problems of the converter caused by manufacturer confidentiality reasons, and obtains a specific and accurate complex frequency domain admittance model of the AC converter to analyze the grid-connected stability problem of the AC converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic diagram of a flow chart of a complex frequency domain admittance matrix modeling method provided by an embodiment of the present invention; Figure 2 A topological diagram of a four-node industrial park provided in an embodiment of the present invention; Figure 3 A schematic diagram of the energy storage side control structure of a photovoltaic power generation device provided by an embodiment of the present invention; Figure 4 This is a Bode diagram of the vector fitting results of the photovoltaic power generation equipment provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The enumerated embodiments are only used to explain the present invention but not to limit the scope of the present invention.

[0025] Reference Figure 1 This embodiment provides a method for modeling an industrial park complex frequency domain admittance matrix based on vector fitting technology, and the method includes the following steps: S101, using the grid-connected point disturbance method to measure the real-time amplitude-frequency and phase-frequency characteristic curves of each new energy unit in the grid-connected operation state of the industrial park, and obtaining the impedance amplitude and phase frequency points of each new energy unit, specifically including the following steps: S11. Collect the three-phase voltage and current operation data of each new energy unit, use the feedforward neural network to fit the three-phase voltage and current operation data of each new energy unit, and establish a digital twin model.

[0026] S12, the disturbance frequency imposed on each renewable energy unit at the grid connection point is Small signal voltage disturbance ,in 1~4000, corresponding to 1~4000Hz.

[0027] S13. Calculate the difference between the digital twin model and the grid-connected current of each new energy unit after the small signal voltage disturbance to obtain the small signal current response , and Fourier analysis is performed on it to obtain the current response of each new energy unit under voltage disturbance in the complex frequency domain, which is expressed as follows: (1) in, is the frequency domain signal, For discrete Fourier analysis, is the function for Fourier analysis, i.e., the small signal current response , is the sampling point number, is the number of sampling points, is the natural logarithm, is an imaginary unit, is a natural number.

[0028] S14. Calculate the disturbance frequency based on Fourier analysis results The ratio of the small signal current response and the small signal voltage disturbance intensity at , and the corresponding complex frequency domain impedance .

[0029] S15. Modify the disturbance frequency , and the amplitude-frequency and phase-frequency characteristic curves of the impedance Z of the new energy unit in the range of 1~4000Hz are obtained.

[0030] S16: When each new energy unit is running, frequency disturbance is injected in real time and cyclically Obtain complex frequency domain impedance for small signal voltage disturbances from 1 to 4000 Hz , and according to the complex frequency domain impedance The data is used to determine whether to update the impedance Z of the new energy unit; the disturbance frequency For example, for 1< <4000, if , then update for Otherwise, keep Keep unchanged and continue to inject disturbance at the next frequency point, where is the frequency.

[0031] S102, based on the frequency points of the impedance amplitude and phase of each new energy unit, obtaining the peak number of each new energy unit, determining the order of the complex frequency domain impedance of the new energy unit according to the peak number of each new energy unit, and then determining the order of the vector fitting, specifically including: Draw a Bode diagram for each frequency point obtained in step S101, observe its peak value based on the impedance part in the Bode diagram, and determine the order of fitting to be selected based on the number of Bode diagram peaks. , among which The frequency at which the peak occurs is .

[0032] S103, based on the order of vector fitting, using vector fitting technology to segmentally identify the complex frequency domain impedance model of each new energy unit, and obtain segmented accurate parameters of the complex frequency domain impedance model, specifically including the following steps: S31. Divide the transfer function of the complex frequency domain impedance of each new energy unit into segments. If the order of fitting is =1, no segmentation; if >1, then the first segment is , No. Duan Wei , No. Duan Wei ,in, The Bode plot of the complex frequency domain impedance curve is The frequency corresponding to the peak value is is the vector fitting order.

[0033] S32. Definition The transfer function form of the complex frequency domain impedance of the new energy unit in the frequency band is used, and vector fitting is performed based on the transfer function form of the complex frequency domain impedance of the new energy unit, which is expressed as follows: (2) in, is the transfer function of the complex frequency domain impedance of the new energy unit, is the order of each segment in the piecewise fitting (its value is generally selected as 1), For the A point, , , , are the parameters to be determined through vector fitting, is the independent variable.

[0034] The vector fitting is performed based on the transfer function form of the complex frequency domain impedance of the new energy unit, and specifically includes the following steps: S3.1, uniformly select from the fitting frequency band N Initial Pole , define an unknown function , which satisfies the multiplication of the fitting transfer function with have the same poles, expressed as follows: (3) in, To fit the transfer function, for The conjugate value of; Compare the second line of formula on the right side of formula (3) with Multiplying together, it is expressed as follows: (4) in, is the frequency domain sampling point, , a, b, are the unknown substitution parameters respectively.

[0035] S3.2, the frequency points in step S101 are brought in to solve the vector fitting linear equations formula, which is expressed as follows: (5)

[0036]

[0037]

[0038] in, is the coefficient matrix in the vector fitting algorithm, is the number of frequency sampling points, is the unknown vector of the vector fitting equation, is the right-hand side term of the vector fitting algorithm, is a complex frequency variable, is the frequency response value of the objective function, For the The residual of the extreme point, For the The conjugate value of the residual at the extreme point, To perform a transpose operation on a matrix.

[0039] S3.3, based on steps S3.1 and S3.2, in solving , a, b, After the parameters are calculated, the fitting transfer function is obtained according to formula (3): The expression is as follows: (6) in, and They are and The zero point of , formula (6) can be expressed as: (7) in, Zero point To fit the transfer function The extreme points of can be obtained by solving the eigenvalue method , which is expressed as follows: (8) in, is a Matlab command (used to obtain the matrix ), is a diagonal matrix whose diagonal elements are the initial poles ; is a column vector whose elements are all 1; To include remainder The row vector of .

[0040] S3.4. Repeat the calculation process of formula (5) to formula (8) in steps S3.2-S3.3 to gradually obtain more accurate vector fitting results.

[0041] S33, based on the vector fitting results, integration The transfer function of the complex frequency domain impedance of the new energy unit in each frequency band is obtained, and the piecewise transfer function of the complex frequency domain impedance of the new energy unit is obtained as follows: , which is expressed as follows:

[0042] in, , They are the first and second segments after vector fitting. The transfer function of the segment, is the transfer function of the complex frequency domain impedance of the new energy unit, is the frequency, and is the complex frequency domain impedance Bode plot and The frequency corresponding to the peak.

[0043] S34. In the case of no segmentation, repeat step S32 to obtain the entire segment transfer function of the complex frequency domain impedance of the new energy unit: , the piecewise transfer function And the entire transfer function After weighting, the final transfer function of the complex frequency domain impedance of each new energy unit is obtained as follows: , which is expressed as follows:

[0044] in, and are weight coefficients, which are generally taken as 0.5.

[0045] S104. Based on the complex frequency domain impedance model of each new energy unit, combined with the line topology information and line parameters in the industrial park, a complex frequency domain admittance matrix of the industrial park is established, which specifically includes the following: Establish multiple nodes according to the topological structure of the industrial park; For the diagonal elements , the diagonal elements of each node are the algebraic sum of the complex frequency domain admittances of all components connected to the node; For off-diagonal elements , the off-diagonal elements represent the negative values ​​of the complex frequency domain admittance between two nodes; Symmetry, the elements of the complex frequency domain admittance matrix are symmetric about the main diagonal, that is, = ; Based on the above characteristics of the complex frequency domain admittance matrix of the industrial park, the four-node complex frequency domain admittance matrix is ​​expressed as follows:

[0046] If a node is connected in parallel with a grounded branch , the complex frequency domain admittance matrix can be transformed into:

[0047] The topology of the four-node industrial park is as follows Figure 2 As shown, it includes photovoltaic power generation equipment, wind power generation equipment, hydrogen production equipment, infinite power supply and connecting wires; the wind power generation capacity is 500kW, the photovoltaic power generation capacity is 10kW, the hydrogen production equipment capacity is 10kW, and the specific parameters of the wires and generators are shown in Table 1 below: Table 1

[0048] The energy storage side control structure of the photovoltaic power generation equipment is as follows: Figure 3 As shown in the figure, is the DC side voltage, , , The filter is composed of is passive damping, For infinite power, is the inverter output current, , For a given output current, is the system angular frequency, usually taken as ; is the PWM modulation signal, , They are current sampling delay and voltage sampling delay respectively. is the frequency domain expression of the delay, is the sampling delay, expressed as follows:

[0049] is the phase-locked loop transfer function, expressed as follows:

[0050] in, and They are the proportional control coefficient and integral control coefficient of the phase-locked loop respectively; the controller voltage loop first samples the grid voltage, and after a sampling delay, the result is sent to the phase-locked loop, and the phase-locked loop outputs phase angle information to the current loop; The current loop is the control link of the system output. The sampled current is sent to the control system after sampling delay. The current information is converted to coordinate system; at the same time, the control signal is also converted to In the coordinate system, the error is obtained by comparing with the sampling signal difference. The error is corrected by the PR controller and then undergoes an inverse Clark transform, and finally used as a PWM modulator signal to control the PWM output.

[0051] like Figure 4 As shown in the figure, the vector fitting results of the photovoltaic power generation equipment are displayed. The disturbance injection frequency point is selected according to 1:5:1000, and the fitting order is set to 8. The scattered points in the figure are the actual measured data, and the solid line is the vector fitting result. It can be seen that the vector fitting result is consistent with the actual result.

[0052] Based on the complex frequency domain impedance model of each new energy unit, this embodiment combines the line topology information and line parameters in the four-node industrial park, and establishes the complex frequency domain admittance matrix of the four-node industrial park according to the four-node complex frequency domain admittance matrix, which specifically includes the following steps: S41, respectively collecting and analyzing the complex frequency domain impedance information of the photovoltaic power generation equipment, the wind power generation equipment, and the hydrogen production equipment at the corresponding disturbance frequency points; S42, drawing a Bode plot according to the complex frequency domain impedance information, and determining the order of fitting to be selected according to the number of peaks of the Bode plot; S43, performing vector fitting on the four-node industrial park according to the order of fitting to be selected to obtain impedance results; The impedance results of various equipment in the four-node industrial park can be expressed as: Photovoltaic power generation equipment: (1820063171227027 / 35184372088832 - 3247379264791407i / 281474976710656) / (s + (2919633481258255 / 140737488355328 - 2249213456603405i / 140737488355328)) + (1820063171227027 / 35184372088832 + 3247379264791407i / 281474976710656) / (s + (2919633481258255 / 140737488355328 + 2249213456603405i / 140737488355328)) + 1968152767294939 / (70368744177664*(s - 6329008279353853 / 1125899906842624)) + 4311938400802685 / (8796093022208*(s - 8524990996596231 / 35184372088832)) - (2642684564939107 / 274877906944 + 5340351738696959i / 1099511627776) / (s + (6620793037775075 / 8796093022208 - 8308519720416377i / 17592186044416)) - (2642684564939107 / 274877906944 - 5340351738696959i / 1099511627776) / (s + (6620793037775075 / 8796093022208 + 8308519720416377i / 17592186044416)) + (8362356439062255 / 549755813888 - 3159139800790623i / 549755813888) / (s + (2082175259461917 / 4398046511104 - 6421300226697625i / 1099511627776)) + (8362356439062255 / 549755813888 + 3159139800790623i / 549755813888) / (s + (2082175259461917 / 4398046511104 +6421300226697625i / 1099511627776)) + 4721327007789329 / 18014398509481984 Hydrogen production equipment: 2803409786950655 / (8796093022208*(s - 5919311367852555 / 70368744177664)) - (2662951035825651 / 274877906944 - 8274656406909023i / 1099511627776) / (s + (6390597773090793 / 8796093022208 + 3437403568279981i / 8796093022208)) - (2662951035825651 / 274877906944 + 8274656406909023i / 1099511627776) / (s + (6390597773090793 / 8796093022208 - 3437403568279981i / 8796093022208)) + 5764726097722303 / (140737488355328*(s + 4315188373007271 / 562949953421312)) + (8381884063123789 / 549755813888 - 6457246162570513i / 1099511627776) / (s + (1043763906397199 / 2199023255552 - 1606099629524209i / 274877906944)) + (8381884063123789 / 549755813888 + 6457246162570513i / 1099511627776) / (s + (1043763906397199 / 2199023255552 + 1606099629524209i / 274877906944)) + 3187544514323967 / 18014398509481984 Wind power generation equipment: 4224399476078235 / (17592186044416*(s + 8204319024818089 / 140737488355328)) + (7117966373798719 / 35184372088832 - 5325168461125201i / 140737488355328) / (s + (2443071200439595 / 17592186044416 - 3023421061775005i / 8796093022208)) + (7117966373798719 / 35184372088832 + 5325168461125201i / 140737488355328) / (s + (2443071200439595 / 17592186044416 + 3023421061775005i / 8796093022208)) + 4503261624015589 / (281474976710656*(s - 5956685792391061 / 4503599627370496)) + 2613785018373549 / (4398046511104*(s - 6021643760586325 / 8796093022208)) + (8300149847756637 / 549755813888 - 6260927296545137i / 1099511627776) / (s + (2071349039847839 / 4398046511104 - 802539422664075i / 137438953472)) + (8300149847756637 / 549755813888 + 6260927296545137i / 1099511627776) / (s + (2071349039847839 / 4398046511104 + 802539422664075i / 137438953472)) + 5730719476778187 / (35184372088832*(s - 5406623362818137 / 70368744177664)) - (2763423522391657 / 274877906944 + 2536174117970495i / 549755813888) / (s + (433264647378109 / 549755813888 -243797366785953i / 549755813888)) - (2763423522391657 / 274877906944 - 2536174117970495i / 549755813888) / (s + (433264647378109 / 549755813888 + 243797366785953i / 549755813888)) + 7786431676834377 / 18014398509481984 S44, based on step S43, first establish a complex frequency domain admittance matrix without adding new energy units, and obtain a four-node complex frequency domain admittance matrix. Each row of the four-node complex frequency domain admittance matrix is ​​expressed as follows: First line: [1 / ((17*s) / (25000*pi) + 1 / 100) + 1 / ((23*s) / (25000*pi) + 17 / 1000) + 1 / ((161*s) / (100000*pi) + 4 / 125) + 1 / ((3617*s) / (1000000*pi) + 319 / 5000) + s / (625*pi),-1 / ((17*s) / (25000*pi)+1 / 100),-1 / ((23*s) / (25000*pi)+17 / 1000),-1 / ((161*s) / (100000*pi) + 4 / 125)] Second line: [-1 / ((17*s) / (25000*pi) + 1 / 100), 1 / ((17*s) / (25000*pi) + 1 / 100) + (11*s) / (25000*pi),0,0] Third line: [-1 / ((23*s) / (25000*pi)+17 / 1000),0,1 / ((23*s) / (25000*pi)+17 / 1000)+ (79*s) / (200000*pi),0] Fourth row: [-1 / ((161*s) / (100000*pi)+4 / 125),0,0, 1 / ((161*s) / (100000*pi) + 4 / 125)+ (153*s) / (200000*pi)] Then, the complex frequency domain admittance matrix after adding the new energy unit is established. The second line of the diagonal elements is the photovoltaic power generation equipment, the third line is the hydrogen production equipment, and the fourth line is the wind power generation equipment. The specific expression is: First line: [1 / ((17*s) / (25000*pi) + 1 / 100) + 1 / ((23*s) / (25000*pi) + 17 / 1000) + 1 / ((161*s) / (100000*pi) + 4 / 125) + 1 / ((3617*s) / (1000000*pi) + 319 / 5000) + s / (625*pi),-1 / ((17*s) / (25000*pi)+1 / 100),-1 / ((23*s) / (25000*pi)+17 / 1000),-1 / ((161*s) / (100000*pi) + 4 / 125)] The second line: <h2 style=";text-align:left;direction:ltr">- 3247379264791407i / 281474976710656) / (s + (2919633481258255 / 140737488355328 - 2249213456603405i / 140737488355328)) (1820063171227027 / 35184372088832 + 3247379264791407i / 281474976710656) / (s + (2919633481258255 / 140737488355328 + 2249213456603405i / 140737488355328)) + 1968152767294939 / (70368744177664*(s - 6329008279353853 / 1125899906842624)) + 4311938400802685 / (8796093022208*(s - 8524990996596231 / 35184372088832)) - (2642684564939107 / 274877906944 + 5340351738696959i / 1099511627776) / (s + (6620793037775075 / 8796093022208 - 8308519720416377i / 17592186044416)) - (2642684564939107 / 274877906944 - 5340351738696959i / 1099511627776) / (s + (6620793037775075 / 8796093022208 + 8308519720416377i / 17592186044416)) + (8362356439062255 / 549755813888 - 3159139800790623i / 549755813888) / (s + (2082175259461917 / 4398046511104) - 6421300226697625i / 1099511627776)) + (+8362356439062255 / 5497558138883159139800790623i / 549755813888) / (s + (2082175259461917 / 4398046511104 + 6421300226697625i / 1099511627776)) + 4721327007789329 / 18014398509481984,0,0] Third line: [-1 / ((23*s) / (25000*pi)+17 / 1000),0, 1 / ((23*s) / (25000*pi)+17 / 1000)+(79*s) / (200000*pi)+2803409786950655 / (8796093022208*(s - 5919311367852555 / 70368744177664)) - (2662951035825651 / 274877906944 - 8274656406909023i / 1099511627776) / (s + (6390597773090793 / 8796093022208 + 3437403568279981i / 8796093022208)) - (2662951035825651 / 274877906944 + 8274656406909023i / 1099511627776) / (s + (6390597773090793 / 8796093022208 - 3437403568279981i / 8796093022208)) + 5764726097722303 / (140737488355328*(s + 4315188373007271 / 562949953421312)) + (8381884063123789 / 549755813888 - 6457246162570513i / 1099511627776) / (s + (1043763906397199 / 2199023255552 - 1606099629524209i / 274877906944)) + (8381884063123789 / 549755813888 + 6457246162570513i / 1099511627776) / (s + (1043763906397199 / 2199023255552 + 1606099629524209i / 274877906944)) + 3187544514323967 / 18014398509481984,0] Fourth row: [-1 / ((161*s) / (100000*pi)+4 / 125),0,0, 1 / ((161*s) / (100000*pi) + 4 / 125)+ (153*s) / (200000*pi)+ 4224399476078235 / (17592186044416*(s +8204319024818089 / 140737488355328)) + (7117966373798719 / 35184372088832 -5325168461125201i / 140737488355328) / (s + (2443071200439595 / 17592186044416 -3023421061775005i / 8796093022208)) + (7117966373798719 / 35184372088832 +5325168461125201i / 140737488355328) / (s + (2443071200439595 / 17592186044416 +3023421061775005i / 8796093022208)) + 4503261624015589 / (281474976710656*(s -5956685792391061 / 4503599627370496)) + 2613785018373549 / (4398046511104*(s -6021643760586325 / 8796093022208)) + (8300149847756637 / 549755813888 -6260927296545137i / 1099511627776) / (s + (2071349039847839 / 4398046511104 -802539422664075i / 137438953472)) + (8300149847756637 / 549755813888 +6260927296545137i / 1099511627776) / (s + (2071349039847839 / 4398046511104 +802539422664075i / 137438953472)) + 5730719476778187 / (35184372088832*(s -5406623362818137 / 70368744177664)) - (2763423522391657 / 274877906944+2536174117970495i / 549755813888) / (s + (433264647378109 / 549755813888 -243797366785953i / 549755813888)) - (2763423522391657 / 274877906944 -2536174117970495i / 549755813888) / (s + (433264647378109 / 549755813888 +243797366785953i / 549755813888)) + 7786431676834377 / 18014398509481984] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The complex frequency domain admittance matrix modeling method of industrial parks based on vector fitting technology is characterized by: The method comprises the following steps: S101. Use the grid-connected point disturbance method to measure the real-time amplitude-frequency and phase-frequency characteristic curves of each new energy unit in the grid-connected operation state of the industrial park, and obtain the frequency points of the impedance amplitude and phase of each new energy unit; S102, based on the frequency points of the impedance amplitude and phase of each new energy unit, obtaining the peak number of each new energy unit, determining the order of the complex frequency domain impedance of the new energy unit according to the peak number of each new energy unit, and then determining the order of vector fitting; S103, based on the order of vector fitting, using vector fitting technology to segmentally identify the complex frequency domain impedance model of each new energy unit, and obtain segmented accurate parameters of the complex frequency domain impedance model; S104. Based on the complex frequency domain impedance model of each new energy unit, combined with the line topology information and line parameters in the industrial park, a complex frequency domain admittance matrix of the industrial park is established.

2. The industrial park complex frequency domain admittance matrix modeling method based on vector fitting technology according to claim 1 is characterized in that: The step S101 specifically includes the following steps: S11. Collect the three-phase voltage and current operation data of each new energy unit, use a feedforward neural network to fit the three-phase voltage and current operation data of each new energy unit, and establish a digital twin model; S12. Apply disturbance frequencies of different frequency points to each renewable energy unit at the grid connection point The small signal voltage disturbance is is the frequency, For the frequency points; S13. Calculate the difference between the digital twin model and the grid-connected current of each renewable energy unit after the small signal voltage disturbance to obtain the small signal current response, and perform Fourier analysis on it to obtain the current response of each renewable energy unit under the voltage disturbance in the complex frequency domain, which is expressed as follows: in, is the frequency domain signal, For discrete Fourier analysis, is the function for Fourier analysis, i.e., the small signal current response, is the sampling point number, is the number of sampling points, is the natural logarithm, is an imaginary unit, is a natural number; S14. Calculate the disturbance frequency based on Fourier analysis results The ratio of the small signal current response and the small signal voltage disturbance intensity at , and the corresponding complex frequency domain impedance ; S15. Modify the disturbance frequency , and obtain the amplitude-frequency and phase-frequency characteristic curves of the impedance Z of the new energy unit; S16. When each new energy unit is running, inject small signal voltage disturbance in real time to obtain complex frequency domain impedance , and according to the complex frequency domain impedance The data is used to determine whether to update the impedance of the new energy unit Z .

3. The industrial park complex frequency domain admittance matrix modeling method based on vector fitting technology according to claim 1 is characterized in that: The step S102 includes: drawing a Bode diagram for each frequency point obtained in step S101, and determining the order of fitting to be selected according to the number of peaks of the Bode diagram. .

4. The method for modeling the industrial park complex frequency domain admittance matrix based on vector fitting technology according to claim 1 is characterized in that: The step S103 specifically includes the following steps: S31, segmenting the transfer function of the complex frequency domain impedance of each new energy unit; S32. Definition The transfer function form of the complex frequency domain impedance of the new energy unit in the frequency band is used, and vector fitting is performed based on the transfer function form of the complex frequency domain impedance of the new energy unit, which is expressed as follows: in, is the transfer function of the complex frequency domain impedance of the new energy unit, is the order of each segment in the piecewise fitting, For the A point, , , , are the parameters to be determined through vector fitting, is the independent variable; S33, based on the vector fitting results, integration The transfer function of the complex frequency domain impedance of the new energy unit in each frequency band is obtained, and the piecewise transfer function of the complex frequency domain impedance of the new energy unit is obtained as follows: , which is expressed as follows: in, , They are the first and second segments after vector fitting. The transfer function of the segment, is the transfer function of the complex frequency domain impedance of the new energy unit, is the frequency, and is the complex frequency domain impedance Bode plot and The frequency corresponding to the peak value; S34. In the case of no segmentation, repeat step S32 to obtain the entire segment transfer function of the complex frequency domain impedance of the new energy unit: , weight the piecewise transfer function and the whole-segment transfer function, and obtain the final transfer function of the complex frequency domain impedance of each new energy unit: , which is expressed as follows: in, and are weight coefficients respectively.

5. The method for modeling the industrial park complex frequency domain admittance matrix based on vector fitting technology according to claim 4 is characterized in that: The vector fitting is performed based on the transfer function form of the complex frequency domain impedance of the new energy unit, and specifically includes the following steps: S3.1, uniformly select from the fitting frequency band N Initial Pole , define an unknown function , which satisfies the multiplication of the fitting transfer function with have the same poles, expressed as follows: in, To fit the transfer function, for The conjugate value of S3.2, bring in the frequency points in step S101, and solve the vector fitting linear equations formula, which is expressed as follows: in, is the coefficient matrix in the vector fitting algorithm, is the number of frequency sampling points, is the unknown vector of the vector fitting equation, is the right-hand side term of the vector fitting algorithm, is a complex frequency variable, is the frequency response value of the objective function, For the The residual of the extreme point, For the The conjugate value of the residual at the extreme point, To perform a transpose operation on a matrix; S3.

3. Based on steps S3.1 and S3.2, the fitting transfer function is obtained, which is expressed as follows: in, To fit the transfer function, and They are and The zero point, Zero point To fit the poles of the transfer function, we can obtain ; S3.

4. Repeat the calculation process of steps S3.2-S3.3 to gradually obtain more accurate vector fitting results.

6. The method for modeling the industrial park complex frequency domain admittance matrix based on vector fitting technology according to claim 1 is characterized in that: The complex frequency domain admittance matrix of the industrial park includes: According to the topological structure of the industrial park, multiple nodes are established, and the diagonal elements of each node is the algebraic sum of the complex frequency domain admittances of all components connected to the node; Off-Diagonal Elements Represents the negative value of the complex frequency domain admittance between two nodes; The elements of the complex frequency domain admittance matrix are symmetric about the main diagonal, that is, = .

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