Generalized modal analysis-based power system voltage disturbance determination method, device, equipment, medium and product

Abstract

The application discloses a power system voltage disturbance determination method and device based on generalized modal analysis, equipment, medium and product, relates to the field of power system stability control, and the method comprises the following steps: establishing an impedance model containing all power sources and network elements; constructing a transfer function of bus voltage of a power grid to power source voltage based on the impedance model containing all power sources and network elements; constructing a voltage disturbance margin index based on the transfer function; and determining the influence of disturbance at any point of the power grid on the power source voltage according to the voltage disturbance margin. The above scheme of the application can quantitatively evaluate the specific influence of disturbance of the power grid on the power source voltage.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system stability control, and particularly relates to a power system voltage disturbance determination method and device based on generalized modal analysis, equipment, medium and product. BACKGROUND

[0002] In recent years, the sustained growth of environmental energy generation demand has promoted the development of large-scale renewable energy generation. The penetration rate of converter-interfaced generation (CIG) in the power system has been significantly improved. Compared with synchronous generators (SG), CIG has poor robustness to interference. CIG often causes unstable oscillation, and the characteristics of such oscillation are significantly different from traditional SG-based power systems. CIG is mainly divided into grid-forming (GFM) converters and grid-following (GFL) converters due to different control modes. Unlike GFM, which can improve the support capacity of the grid, GFL will accelerate the spread of oscillation in the power system. How to quantitatively analyze the interaction of converters through the grid has always been an important problem, which requires the development of a new analysis framework to overcome the complexity of the actual model.

[0003] Modal analysis based on the state-space model (MASS) has attracted much attention due to its ability to evaluate system stability and response characteristics using linear algebra. MASS quantifies the contribution of each state variable to a specific mode through participation factors, which helps to identify key influencing factors and potential improvements in the system. A technique that combines automatic excitation technology and an intrinsic system implementation algorithm is applied in power system modal analysis, which successfully estimates modal parameters such as damping ratio and frequency. The method based on selective modal analysis can effectively calculate the degree of coupling between synchronous generators. The peak selection method of modal analysis not only identifies the resonance frequency and quality factor from the Nyquist plot, but also emphasizes the importance of analyzing modal impedance for predicting damping. However, although related research can identify system damping, they still have deficiencies in determining the most influential elements of the system.

[0004] Impedance modeling is widely used in stability analysis of power systems with high penetration of CIG. Some studies have discussed the use of impedance models to identify the key factors affecting system oscillations. Harmonic resonance modal analysis techniques identify the buses with the highest degree of participation in oscillations based on the singularity of the network admittance matrix. The sensitivity of eigenvalues to network element parameters can be used to determine the network elements that affect certain specific oscillation modes. In addition, a harmonic modal analysis alternative formula based on a real symmetric node matrix simplifies the calculation of eigenvalue sensitivity. Eigenvalue trajectories are used to assess harmonic instability caused by controller parameters. The zeros of the loop impedance matrix or node admittance matrix can determine the oscillation modes, and the loop participation factors and node participation factors can be used to understand the origin of oscillations in depth.

[0005] Existing studies mainly determine the key modes affecting the system based on the correlation participation factor analysis results, and adjust the relevant control parameters of the key modes to guide the stable operation of the system. However, the participation factor is essentially the sensitivity of the mode to the state matrix, and reflects the relationship between the mode and the state variable, and cannot quantitatively evaluate the specific impact of the power supply voltage when the power grid is disturbed. Therefore, there is still a gap in the actual description of the strength of the coupling relationship by MASS. SUMMARY

[0006] The purpose of the present application is to provide a power system voltage disturbance method, device, equipment, medium and product based on generalized modal analysis, which can quantitatively evaluate the specific impact of the power supply voltage when the power grid is disturbed.

[0007] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0008] In a first aspect, the present application provides a power system voltage disturbance determination method based on generalized modal analysis, which comprises:

[0009] establishing an impedance model containing all power sources and network elements;

[0010] constructing a transfer function of bus voltage to power supply voltage based on the impedance model containing all power sources and network elements;

[0011] constructing a voltage disturbance margin index based on the transfer function;

[0012] determining the impact of disturbance at any point in the power grid on the power supply voltage according to the voltage disturbance margin.

[0013] Optionally, the establishment of the impedance model containing all power sources and network elements specifically adopts the following formula:

[0014] Z=(I+Z N Y G ) -1 ZN = (Y G + Y N ) -1 = Y -1

[0015] where Z and Y are the system-wide nodal impedance matrix and the system-wide nodal admittance matrix considering the impedance characteristics of the power source, is the nodal impedance matrix of the network, I represents the identity matrix, Y N is the nodal admittance matrix of the network, Y G is the admittance matrix of the power source.

[0016] Optionally, the expression of the transfer function of the grid bus voltage to the power source voltage is as follows:

[0017]

[0018] where ΔU G represents the change value of the power source voltage, Y G is the admittance matrix of the power source, Z and Y are the system-wide nodal impedance matrix and the system-wide nodal admittance matrix considering the impedance characteristics of the power source, and ΔU represents the change value of the grid bus voltage.

[0019] Optionally, the expression of the voltage disturbance margin index is as follows:

[0020]

[0021] where VDM ij (λ i ) represents the voltage disturbance margin index of the power source connected to bus i to bus j, σ i represents the real part of the eigenvalue λ i , Y Gi represents the admittance of the power source connected to bus i, λ i represents the i-th eigenvalue of the system, represents the real part of the eigenvalue λ i , Z ji (s) represents the mutual impedance element of bus j and i in the system-wide nodal impedance matrix, T represents the transpose of the matrix, and |·| F represents the Frobenius norm.

[0022] Optionally, the power system voltage disturbance determination method based on generalized modal analysis further comprises, after the step of "determining the influence of the disturbance of any point of the grid on the power source voltage according to the voltage disturbance margin":

[0023] Parameter setting is performed on the key power source based on the voltage disturbance margin.

[0024] In a second aspect, the present application provides a generalized modal analysis based power system voltage disturbance determination device, comprising:

[0025] An impedance model establishing module is configured to establish an impedance model containing all power sources and network elements;

[0026] A transfer function constructing module is configured to construct a transfer function of grid bus voltage to power source voltage based on the impedance model containing all power sources and network elements;

[0027] A voltage disturbance margin index constructing module is configured to construct a voltage disturbance margin index based on the transfer function;

[0028] An arbitrary point disturbance to power source voltage influence determining module is configured to determine an influence of grid arbitrary point disturbance to power source voltage according to the voltage disturbance margin.

[0029] Optionally, the generalized modal analysis based power system voltage disturbance determination device further comprises:

[0030] A parameter setting module is configured to set parameters of key power sources based on the voltage disturbance margin.

[0031] In a third aspect, the present application provides a computer device, comprising a memory, a processor, a computer program stored in the memory and executable on the processor, and the processor executes the computer program to implement steps of the generalized modal analysis based power system voltage disturbance determination method in any one of the above.

[0032] In a fourth aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement steps of the generalized modal analysis based power system voltage disturbance determination method in any one of the above.

[0033] In a fifth aspect, the present application provides a computer program product, comprising a computer program, and the computer program is executed by a processor to implement steps of the generalized modal analysis based power system voltage disturbance determination method in any one of the above.

[0034] According to the embodiments of the present application, the following technical effects are achieved:

[0035] The application provides a power system voltage disturbance determination method and device based on generalized modal analysis, a medium, equipment and product, which comprises the following steps: establishing an impedance model containing all power sources and network elements; constructing a transfer function of bus voltage to power source voltage based on the impedance model containing all power sources and network elements; constructing a voltage disturbance margin index based on the transfer function; and determining the influence of disturbance at any point of the power grid on the power source voltage according to the voltage disturbance margin. It can be seen that the above method breaks the traditional viewpoint of relying on electrical distance elements to evaluate the influence of the power grid on the power source, effectively solves the quantitative evaluation problem of the influence of power grid disturbance on the power source voltage considering the dynamic characteristics of all power sources and network elements in the power system, fully captures the complex interaction of the converter through the power grid, and verifies the theoretical analysis through numerical calculation results. The research results have certain guiding significance for the current power system with a high proportion of converter interface power sources. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 A flow chart of a power system voltage disturbance determination method based on generalized modal analysis in an embodiment of the present application;

[0038] Figure 2 A system element impedance modeling structure diagram in an embodiment of the present application;

[0039] Figure 3 A power source equivalent circuit transformation diagram in an embodiment of the present application;

[0040] Figure 4 A 14 bus system diagram in an embodiment of the present application;

[0041] Figure 5 A modal voltage sensitivity factor MVSF in an embodiment of the present application ij Thermal map;

[0042] Figure 6 Part (a), part (b) and part (c) of A6 voltage ring are Bode plots of Zdd11-6, Zdd12-6 and Zdd13-6 at 300, 240 and 360 Hz, respectively, part (d), part (e) and part (f) of A6 voltage ring are voltage amplitude change diagrams of power source A6 when the active loads of buses 11, 12 and 13 are increased by 1 p.u. at t=0.1 s at 300, 240 and 360 Hz, respectively.

[0043] Figure 7 Fig. 6 shows a schematic diagram of the voltage amplitude variation of the power supply A6 at any point of the line 13-14 in an embodiment of the present application when the active load of the line 13-14 at different points increases by 1 p.u. at t=0.1 s; ij schematic diagram;

[0044] Figure 8 Fig. 6 shows a schematic diagram of the voltage amplitude variation of the power supply A6 at any point of the line 13-14 in an embodiment of the present application when the active load of the line 13-14 at different points increases by 1 p.u. at t=0.1 s;

[0045] Figure 9 Fig. 7 shows a schematic diagram of the structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0047] The above-mentioned purposes, features and advantages of the present application can be more obvious and easy to understand. The present application will be described in further detail below with reference to the drawings and specific embodiments.

[0048] Referring to Figure 1 , the present application provides a voltage disturbance determination method for a power system based on generalized modal analysis, specifically comprising:

[0049] Step 1: Establish an impedance model containing all power supplies and network elements.

[0050] Figure 2 An impedance modeling of an interconnected power system is shown. The power network elements constitute a network node admittance matrix Y N . The power supply is modeled as a current source in parallel with an admittance, and the power supply admittance matrix is Y G . Y N + Y G constitutes a system node admittance matrix Y, which contains the dynamic characteristics of all elements in the system. Where ΔI Gi is the equivalent injected current of the power supply connected to bus i, ΔU i is the voltage variation value of bus i, Y Gi is the equivalent admittance of the power supply i.

[0051] Specifically, the following steps are included:

[0052] A small-signal model of a heterogeneous power supply power system is established, and impedance modeling is performed on the power supply and the power network thereof, respectively.

[0053] The small-signal model of a power source can be derived from the state equations or measured. It is worth noting that in the impedance modeling of a multi-machine power system, the impedance models of all power sources derived from the state equations need to ensure that the coordinate systems of all power sources are aligned. Gi Y

[0054]

[0055] where Z Gi is the impedance model of the power source connected to bus i, and are the corresponding elements of the dq rotating coordinate system. If there is no power source at bus i, Y Gi = 0.

[0056] The power source admittance matrix of the system can be obtained from the impedance models of each power source, as follows:

[0057]

[0058] where Y G ∈ 2n x 2n represents the admittance matrix of the system power sources, and n is the number of system nodes.

[0059] The network node admittance matrix Y N of the power network is established as follows:

[0060]

[0061] where Y Nij represents the mutual admittance element between buses i and j, and Y Nii represents the self-admittance element of bus i.

[0062] Consider taking the disturbance value of the injected current at each bus in the network as input:

[0063] Δu = [ΔI G1 … ΔI Gi … ΔI Gn ] T (4)

[0064] where ΔI Gi is the disturbance value of the injected current at bus i.

[0065] Take the voltage change value at each bus of the network as output:

[0066] Δy = [ΔU1… ΔU i … ΔU n ] T (5)

[0067] where ΔU i is the injected current disturbance value of bus i.

[0068] The input-output transfer function matrix can be obtained by using the closed-loop formula:

[0069] Δy = (I + Z N Y G ) -1 Z N Δx (6)

[0070] where, is the node impedance matrix of the network, and I represents the unit matrix.

[0071] Thus, the transfer function matrix of the entire system is:

[0072] Z = (I + Z N Y G ) -1 Z N = (Y G + Y N ) -1 = Y -1 (7)

[0073] where Z and Y are the full-system node impedance matrix and the full-system node admittance matrix considering the impedance characteristics of the power sources.

[0074] Step 2: Construct the transfer function of the bus voltage to the power source voltage based on the impedance model containing all power sources and network elements.

[0075] Figure 3 The equivalent change result of the power source connected to bus i is shown. The equivalent circuit of the power source is transformed from a current source in parallel with an admittance to a voltage source in series with an admittance. Where ΔU Gi is the voltage value of the voltage source. The voltage value of the voltage source and the equivalent injected current of the current source satisfy ΔU Gi = (Y Gi ) -1 ΔI Gi .

[0076] ΔU Gi = (Y Gi ) -1 ΔI Gi represents the voltage change amount of power source i. If bus i is not connected to an actual power source, then:

[0077] Y Gi = diag(ε,ε) (8)

[0078] where ε represents a very small number, which ensures that Y Gi is invertible. Equation (8) can be written in matrix form:

[0079] ΔU G = (Y G ) -1 ΔI G (9)

[0080] where ΔU G represents the source voltage vector, ΔI G represents the source current vector. Since ΔI G = YΔU, ΔU is the network bus voltage vector in equation (5). Then we have:

[0081]

[0082] Therefore, equation (10) describes the influence of the network bus voltage on the source voltage. Gij(s) represents the transfer function of bus j voltage to source i voltage, which is a 2-dimensional square matrix.

[0083] Step 3: Construct the voltage disturbance margin index based on the transfer function.

[0084] For the determinant H D (s) of any square matrix H(s), it is expanded by the lth column:

[0085]

[0086] where C kl is the algebraic cofactor of the element H kl in the kth row and lth column of H(s).

[0087] Then we have: If λ is the solution of H D (λ) = 0, when H kl is disturbed, and the value of the disturbance is ΔH kl , then we have:

[0088] H D (λ + Δλ, H kl + ΔH kl ) = 0 (13)

[0089] where Δλ is the change value of the equation solution.

[0090] Taylor expand equation (13) and ignore the high-order infinitesimal terms:

[0091]

[0092] Substitute equation (12) and equation (13) into equation (14) to get

[0093]

[0094] Then we have:

[0095]

[0096] where, is the sensitivity matrix of λ to H(λ), * denotes the adjoint matrix.

[0097] The matrix G(s) is the inverse matrix of H(s), and the determinant of G(s) at λ is:

[0098]

[0099] Combining equation (17) and equation (18), we have:

[0100]

[0101] Therefore, the sensitivity of λ to H(λ) is equal to G(s) T The negative value of the determinant at λ.

[0102] In general, if the input and output ports of interest are selected to form the input vector Δu1 and the output vector Δy1, and their dimensions are both m. That is, the input matrix B selects the corresponding columns to form B1 and the output matrix C selects the corresponding columns to form C1, and the feedforward matrix is modified to D1. At this time, the system transfer function matrix is:

[0103]

[0104] where A is the system state matrix.

[0105] If G(s) is invertible and its inverse matrix is H(s), H(s) is an m-order square matrix, and the determinant of H(s) is the inverse of the determinant of G(s), that is:

[0106]

[0107] Substituting ΦΨ = I and A = ΦΛΨ into equation (21), we get:

[0108]

[0109] where,

[0110] Therefore, equation (22) can be simplified as:

[0111]

[0112] where s is the Laplace operator, φ j is the jth column vector of matrix Φ, and ψ j is the jth row vector of matrix Ψ.

[0113] When s = λ i , formula (24) is simplified as:

[0114]

[0115] When the ith mode is controllable and observable, there is ψ i B1≠0 and C1φ i ≠0, so formula (25) is simplified as:

[0116]

[0117] At this time, there is:

[0118] rank(C1φ i ψ i B1)≤rank(φ i ψ i )≤rank(φ i ) = 1 (27)

[0119] Where, rank() represents the rank of the matrix.

[0120] Because C1φ i ≠0 and ψ i B1≠0, there is:

[0121] 1≤rank(C1φ i ψ i B1) (28)

[0122] Therefore, rank(C1φ i ψ i B1) = 1, then |C1φ i ψ i B1| has m-1 zero roots and one non-zero root η:

[0123] |C1φ i ψ i B1| = η·0 m-1 (29)

[0124] Substitute formula (29) into formula (26), there is:

[0125]

[0126] When the ith mode is uncontrollable or unobservable, there is ψ i B1=0 or C1φ i =0, so there is:

[0127] rank(C1φ i ψ i B1)≤min{rank(C1φ),rank(ψi B1)} = 0 (31)

[0128] where min{} means taking the minimum value.

[0129] Note that |D1| is not equal to infinity, in this case, equation (25) can be simplified as:

[0130]

[0131] In summary, |H(λ i )| = 0 if and only if the ith mode is controllable and observable.

[0132] When the ith mode is controllable and observable, |H(λ i )| = 0, combining equation (25) gives:

[0133]

[0134] From equation (24), when s≠λ i , there exists H(s)≠0, in this case, H(s) and G(s) are invertible.

[0135] In summary, equation (33) is essentially a modal analysis, and it is defined as a generalized modal analysis. The state-space modal analysis is exactly the case that B1 and C1 are identity matrices in the generalized modal analysis. Here, the generalized modal analysis is applied to the voltage port.

[0136] Note that Z is the transfer function of the whole system in equation (7), thus |Y(λ i )| = 0:

[0137]

[0138] Therefore, equation (34) satisfies the condition of the generalized modal analysis application, thus:

[0139]

[0140] Therefore, equation (35) describes the sensitivity of the mode λ i to . Expanding equation (35) gives:

[0141]

[0142] where Z ji (s) is the mutual impedance between bus j and bus i in equation (7).

[0143] It is worth noting that if bus i is not connected to an actual power source, then equation (36) is 0. λ i to The sensitivity of the bus voltage to the source current is zero, so the assumption of equation (8) does not affect the calculation.

[0144] From the above discussion, equation (36) specifically demonstrates an application of generalized modal analysis. However, equation (36) is a two-dimensional matrix and is not convenient to describe, so the modal voltage sensitivity factor (MVSF) is defined to comprehensively measure this relationship. Specifically, the Frobenius norm of equation (36) is This is used to represent the modal voltage sensitivity of bus j to source i:

[0145]

[0146] Equation (37) represents a sensitivity, so we have:

[0147]

[0148] For the sake of conservatism, take |Δλ i | F The maximum value is -σ i , σ i is the real part of λ i = σ i +jω i .

[0149] The voltage disturbance margin (VDM) of bus j to source i is defined as

[0150]

[0151] And the analysis object is extended from the bus to the line j-k. Let f be a point in the line, z jk represents the line impedance between bus j and bus k, and l is the percentage of the distance from point f to bus j in the overall distance. In order to extend the application of VDM, it is necessary to calculate the From equation (39), we only need to get Z fi . We can regenerate the full system node impedance matrix with the added node f. However, this will result in a large amount of calculation, and we need to regenerate it for different points on the line. The process of directly generating Z fi from the original full system node impedance matrix Z is given below.

[0152] Write the KVL equation as:

[0153]

[0154] where, U f, U j and U k are the voltages at nodes f, j and k, respectively. jk and y jk are the line impedance and admittance, respectively. jk is the current between lines jk.

[0155] Only when bus i injects current I i , which is defined according to the nodal impedance matrix:

[0156] Z fi = (1 - l)Z ji + lZ ki (41)

[0157] Therefore is:

[0158]

[0159] When l equals 0 or 1, equation (42) is and Thus the VDM of any point to the power source is completely established.

[0160] Step 4: Determine the influence of the disturbance of any point of the power grid on the voltage of the power source according to the voltage disturbance margin.

[0161] The VDM and GS are indexes of the multi-infeed power system. The interaction relationship of each power source through the power grid is naturally reflected in the indexes. As can be seen from equation (39), the VDM ij (λ i ) is composed of the real part of the system eigenvalue, the admittance of the power source and the element of the nodal impedance matrix of the whole system. The system eigenvalue is obtained by solving the determinant of the nodal admittance matrix of the whole system being equal to 0, and the nodal impedance matrix of the whole system and the nodal admittance matrix of the whole system are inverse matrices of each other. The nodal admittance matrix of the whole system is composed of the dynamic admittance of all elements of the system. The poles of the system are reflected in the denominator of the nodal impedance matrix of the whole system, and thus the interaction relationship of the power sources is naturally reflected in the indexes.

[0162] The VDM is a local small-signal index. Its positive and negative indicate whether the system is small-signal stable, and its size indicates the size of the stability margin. Specifically, the value of the VDM ij indicates the degree of tolerance of the power source i to the disturbance of bus j at the oscillation frequency. The larger the VDM is, the lower the sensitivity of the power source to the disturbance is, and the stronger the power grid is.

[0163] Step 5: Select the key power source of the system to perform parameter setting to enhance the small-signal stability of the system

[0164] If the VDM values of most buses to a certain power source are generally low, it means that most bus disturbances will have a great impact on the voltage of the power source. Therefore, it can be determined that the power source is a key power source in the system, which has a dominant influence on the stability of the system. Therefore, in a large system, the selection range of the key power source affecting the stability of the system can be narrowed according to the value of VDM. If the value of VDM increases after parameter setting of the key power source, it means that the robustness of the power source to the disturbance of the power grid has been improved, thereby guiding the enhancement of the small signal stability of the power system.

[0165] The method of the application will be described in detail below in combination with specific examples:

[0166] As shown in Figure 4 , it is a 14-bus system. SG connects buses 1, 2, 3 and 8. GFM connects bus 6. GFL connects buses 11, 12 and 13. A11, A12 and A13 are the same in the rest of the control parameters except for the current loop bandwidth. Table 1 gives the current loop control parameters of the three GFLs, the impedance of the line connected with GFM and the calculated value of VDM when the eigenvalue is -4.09+30.06i. ij The impedance of line 6-12 is the largest and the impedance of line 6-13 is the smallest, which indicates that the electrical distance from A6 to A12 is the farthest and the electrical distance from A6 to A13 is the closest. Naturally, it can be considered that the disturbance of bus 12 has the smallest impact on A6 and the disturbance of bus 13 has the largest impact on A6.

[0167] Table 1 Line impedance, current loop bandwidth and VDM value ij

[0168] A11 A12 A13 Line impedance to A6 / p.u. 0.09498+0.1989i 0.12291+0.25581i 0.06615+0.13027i Current loop bandwidth / Hz 400 300 350

[0169] When the voltage loop bandwidth of A6 is 300 Hz, the modal voltage sensitivity factor MVSF is obtained according to formula (41). ij The results are shown in the heat map of Figure 5 . It is obvious that the sensitivity of bus 12 to A6 is the highest. Figure 6 The frequency spectrum peak of Z in part (a) of dd12-6 is the highest at 30.06 Hz, which implies that bus 12 has the largest impact on A6. The VDM 6-12 , VDM 6-11 and VDM 6-13 in Table 2 are 0.249, 0.365 and 0.291 respectively. Therefore, the disturbance of bus 12 has the highest impact on A6, which is just opposite to the conclusion of the analysis of the electrical distance. Figure 5 ​part (d) of FIG. 6 shows the voltage amplitude variation of source A6 when bus 11, 12 and 13 have a 1 p.u. active load increase at 0.1 s, respectively. The oscillation peak in the figure shows that bus 12 has the most influence on A6, while bus 11 has the least influence on A6. The simulation results are the same as the VDM ij characterization results.

[0170] VDM of different A6 voltage loop bandwidths in Table 2 ij values

[0171] Voltage loop bandwidth / Hz VDM 6-11 ]]> VDM 6-12 ]]> VDM 6-13 ]]> 300 0.365 0.249 0.291 240 0.259 0.208 0.221 360 0.479 0.364 0.394

[0172] To reflect the interaction of GFM and GFL again, the voltage loop bandwidth of A6 is changed to 240 Hz and 360 Hz, respectively. The frequency spectrum of the partial elements of the system node impedance matrix is shown in Figure 6 part (b) of FIG. 6 and Figure 6 part (c) of FIG. 6. Compared with Figure 6 part (a) of FIG. 6, Figure 6 the frequency peak of part (b) of FIG. 6 increases, while Figure 6 the frequency peak of part (c) of FIG. 6 decreases. This implies that the oscillation peak of A6 increases and decreases, respectively, after the disturbance. With the same disturbance, Figure 6 part (e) of FIG. 6 and Figure 6 part (f) of FIG. 6 show that the oscillation peak increases and decreases, respectively, compared with Figure 6 part (d) of FIG. 6. The VDM ij of the three groups of experiments is shown in Table 2, and the simulation results prove the effectiveness of the VDM ij in describing the influence of the grid on the source.

[0173] The interaction of the converter through the grid is well reflected by the VDM ij , which breaks the traditional view of evaluating the disturbance propagation according to the distance.

[0174] In addition, the VDM ij of line 13-14 at different positions is calculated by formula (42) as shown in Figure 7 . Figure 7 The horizontal coordinate represents the percentage distance of any point in line 13-14 from bus 13. The VDM ij of line 13-14 at different positions monotonically changes with the increase of the distance percentage. With the disturbance set at four different positions of line 13-14, Figure 8 the voltage amplitude variation results of A6 are consistent with the calculation results of Figure 7 .

[0175] Based on the same inventive concept, the embodiments of the present application also provide a generalized modal analysis based power system voltage disturbance determination device for implementing the generalized modal analysis based power system voltage disturbance determination method described above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more embodiments of the generalized modal analysis based power system voltage disturbance determination device provided below can be referred to the limitations of the generalized modal analysis based power system voltage disturbance determination method described above, and will not be described here.

[0176] In an exemplary embodiment, a generalized modal analysis based power system voltage disturbance determination device is provided, comprising:

[0177] An impedance model establishing module is configured to establish an impedance model containing all power sources and network elements.

[0178] A transfer function constructing module is configured to construct a transfer function of grid bus voltage to power source voltage based on the impedance model containing all power sources and network elements.

[0179] A voltage disturbance margin index constructing module is configured to construct a voltage disturbance margin index based on the transfer function.

[0180] An arbitrary point disturbance influence on power source voltage determining module is configured to determine the influence of grid arbitrary point disturbance on power source voltage according to the voltage disturbance margin.

[0181] A parameter setting module is configured to set parameters of key power sources based on the voltage disturbance margin.

[0182] In an exemplary embodiment, a computer device can be a server or a terminal, and its internal structure diagram can be as shown in Figure 9As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through the system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capability. The memory of the computer device includes a non-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 database of the computer device is used to store the processing data of the power system voltage disturbance determination method based on generalized modal analysis. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with the terminal outside through the network connection. The computer program is executed by the processor to realize a power system voltage disturbance determination method based on generalized modal analysis.

[0183] Those skilled in the art can understand that, Figure 9 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0184] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to realize the steps in each of the method embodiments described above.

[0185] In one exemplary embodiment, a computer readable storage medium is provided, storing a computer program, which is executed by a processor to realize the steps in each of the method embodiments described above.

[0186] In one exemplary embodiment, a computer program product is provided, including a computer program, which is executed by a processor to realize the steps in each of the method embodiments described above.

[0187] It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of related data need to comply with relevant regulations.

[0188] 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. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, databases or other media used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0189] The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a blockchain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0190] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0191] The principles and implementation modes of the present application are described by applying specific examples in the present application. The above-mentioned embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the present application should not be understood as a limitation.

Claims

1. A method for determining voltage disturbance in a power system based on generalized modal analysis, characterized in that, The power system voltage disturbance determination method based on generalized modal analysis comprises: establishing an impedance model containing all power sources and network elements, ensuring that the coordinate systems of the impedance models of the power sources in the multi-machine power system are aligned; constructing a transfer function of the bus voltage of the power grid to the power source voltage based on the impedance model containing all power sources and network elements; constructing a voltage disturbance margin index based on the transfer function; the expression of the voltage disturbance margin index is as follows: wherein denotes the bus i connected power supply j voltage disturbance margin index, denotes the real part of the eigenvalue , denotes the bus i connected power supply admittance, denotes the system i th eigenvalue, denotes the real part of the eigenvalue at the ji ( s ) denotes the mutual impedance element of the bus j and i in the system-wide node impedance matrix, T denotes taking the transpose of a matrix, denotes taking the Frobenius norm; The impact of a disturbance at any point in the power grid on the power supply voltage is determined based on the voltage disturbance margin; the percentage of the node impedance at any point in the power grid line through the distance from that point to the busbars at both ends of the line is also considered. l calculate, ; l For any point f to bus j The percentage of distance relative to the total route distance. For any point f With busbar i The node impedance between them busbar j With busbar i Impedance between; based on arbitrary points f node impedance any point on the line f busbar i Voltage disturbance margin index of the connected power supply The expression is: ； The power system voltage disturbance determination method based on generalized modal analysis further comprises, after the step of determining the influence of the disturbance at any point of the power grid on the power source voltage according to the voltage disturbance margin: performing parameter setting on the key power sources based on the voltage disturbance margin; the key power sources are defined as the power sources whose bus has a low VDM value, i.e., the bus disturbance has an influence on the voltage of the power sources.

2. The method of claim 1, wherein, The impedance model containing all power sources and network elements is established by using the following formula: wherein and is the full system node impedance matrix and the full system node admittance matrix taking into account the power supply impedance characteristics, is the node impedance matrix of the network, I denotes the identity matrix, is the network node admittance matrix, Y G is the power supply admittance matrix.

3. The method of claim 1, wherein, The expression of the transfer function of the bus voltage of the power grid to the power source voltage is as follows: wherein denotes the power supply voltage variation, Y G is the power supply admittance matrix, and are the full system node impedance matrix and the full system node admittance matrix taking into account the power supply impedance characteristics, denotes the grid bus voltage variation.

4. A generalized modal analysis based power system voltage disturbance determination apparatus, characterized by, The method for implementing any one of claims 1-3 comprises: an impedance model establishing module for establishing an impedance model containing all power sources and network elements; a transfer function constructing module for constructing a transfer function of the bus voltage of the power grid to the power source voltage based on the impedance model containing all power sources and network elements; a voltage disturbance margin index constructing module for constructing a voltage disturbance margin index based on the transfer function; an influence determining module for determining the influence of the disturbance at any point of the power grid on the power source voltage according to the voltage disturbance margin.

5. The generalized modal analysis based power system voltage disturbance determination apparatus according to claim 4, wherein, The power system voltage disturbance determination device based on generalized modal analysis further comprises: a parameter setting module for performing parameter setting on the key power sources based on the voltage disturbance margin.

6. A computer device comprising: A memory and a processor for storing a computer program stored on the memory and executable on the processor, characterized in that the processor executes the computer program to implement the steps of the power system voltage disturbance determination method based on generalized modal analysis according to any one of claims 1-3.

7. A computer readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the steps of the power system voltage disturbance determination method based on generalized modal analysis according to any one of claims 1-3.

8. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method according to any one of claims 1-3.

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