Evaluation method and device for effectiveness of alternating current power distribution network resonance suppression scheme and storage medium

Abstract

The application provides an evaluation method for the effectiveness of a resonance suppression scheme for an alternating current power distribution network, which comprises the following steps: establishing a frequency domain node admittance matrix of the power distribution network, and drawing a single frequency resonance suppression safety domain; drawing resonance suppression safety domains in a frequency band of interest, and analyzing the distribution characteristics of the safety domains in the frequency band; comparing the obtained resonance suppression safety domains with the distribution of the resonance suppression strategy admittance change in the safety domain, demonstrating the effectiveness of the resonance suppression strategy, and giving suggestions for resonance suppression strategy selection and parameter optimization. The application also provides corresponding devices and storage media. By implementing the application, matrix inversion operation can be avoided, the resonance suppression strategy has good universality for different types, and can be applied to various scenes.

Description

Technical Field

[0001] This invention relates to the field of resonance analysis technology, and in particular to a method, apparatus and storage medium for evaluating the effectiveness of resonance suppression schemes in AC distribution networks. Background Technology

[0002] During the operation of power distribution networks, resonance suppression is necessary to improve network stability. Existing technologies can achieve resonance suppression through methods such as improving control methods, installing resonance suppression equipment, and changing system parameters. However, current research on resonance suppression strategies typically focuses on specific scenarios, paying less attention to their applicability in different scenarios, and lacking corresponding methods for analyzing the effectiveness of resonance suppression strategies.

[0003] Due to the diverse equipment types, complex topologies, and intricate interactions within AC distribution networks, the causes and characteristics of resonance also exhibit diverse features. The same resonance suppression method can produce significantly different results in different scenarios. Therefore, inappropriate methods may reduce equipment performance and operating efficiency, failing to guarantee effective resonance suppression. Furthermore, the coupling of the resonance suppression component with the mathematical models of other parts of the system makes targeted adjustments and optimizations even more difficult.

[0004] Therefore, it is necessary to analyze the effectiveness of resonance suppression methods in different scenarios to help promote the application and optimization of existing resonance suppression methods. However, in the current technology, no universal evaluation method has been found for the effectiveness of AC distribution network resonance suppression schemes in different scenarios. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to propose an evaluation method and device for the effectiveness of resonance suppression schemes in AC distribution networks, so as to solve the problems of limited application scenarios and incompatibility between resonance scenarios and resonance suppression methods.

[0006] The technical solution adopted in this invention is to provide a method for evaluating the effectiveness of AC distribution network resonance suppression schemes, comprising the following steps:

[0007] Step S1: Establish the frequency domain node admittance matrix of the distribution network, and at least obtain the node impedance amplitude-frequency distribution and the information of the active node;

[0008] Step S2: Determine the general evaluation index for the effectiveness of resonance suppression based on nodal admittance. All general evaluation indices are used to determine the effectiveness of the resonance suppression method.

[0009] Step S3 is used to determine the safe region, dangerous region, and critical boundary of resonance suppression at a single frequency.

[0010] Step S4: Based on the distribution of the node impedance resonant peaks, identify the frequency band of interest for resonance suppression, and evaluate the conservative safety domain for resonance suppression based on the frequency band of interest.

[0011] Step S5: Evaluate the ideal safe domain for resonance suppression, and evaluate the effectiveness of the admittance change of the actual suppression strategy based on the proposed safe domain boundary and conservative safe domain.

[0012] Preferably, step S2 further includes:

[0013] In an AC system along the dq axis, let the reshaping admittances of the d and q axes be δ. d δ q The node admittance and impedance matrix after resonance suppression are respectively Y δdq Z δdq ;

[0014] For the d-axis self-impedance of the node, the following general evaluation index for resonance suppression effectiveness based on nodal admittance is determined:

[0015] |Y * δdq,f (p d ,p d )| 2 |det(Y 0,f )| 2 -|det(Y δdq,f )| 2 |Y * 0,f (p d ,p d )| 2 <0 (3)

[0016] When the above equation is satisfied, it is determined that the resonance energy can be effectively suppressed, where det(Y) 0,f ) is the determinant of the matrix that suppresses the admittance of the preceding node, and det(Y) δ,f Y is the determinant of the matrix for suppressing the nodal admittance. * δdq,f (p d ,p d ) represents the changes in d-axis and q-axis admittance, respectively δ d δ q At frequency f, the nodal admittance matrix has self-admittance along the d-axis at node p; Y * 0,f (p d ,p d When the changes in d-axis and q-axis admittance are 0, the nodal admittance matrix at frequency f is self-admitted along the d-axis at node p.

[0017] Preferably, step S3 further includes:

[0018] Let det(Y) 0,f ) = Y 0,r +jY 0,i ,Y*0,f(p d ,p d The following formula, y*d,r + jy*d,i, is used to determine the criteria for judging the resonance suppression safety region of the admittance change:

[0019]

[0020] in:

[0021]

[0022] From equation 4), it can be seen that when the real part δ of the reshaped admittance is used... d,r δ d,i When the variable is used, the boundary of its resonance suppression region is a circle centered at (-Q2 / Q1, -Q3 / Q1). A circle with radius is defined, and its boundary always passes through the origin. The region outside the circle is defined as the resonance suppression safe region, and the region inside the circle is defined as the resonance amplification region, i.e., the resonance suppression danger region. The boundary between the safe region and the danger region is the boundary between the resonance suppression safe region and the suppression danger region.

[0023] Preferably, in step S4, the frequency band of interest is determined with 30% of the resonant peak impedance as the boundary, the range and frequency interval of the resonant frequency band of interest are set, and the resonant suppression safety domain within each frequency band is plotted one by one.

[0024] Preferably, step S5 further includes: defining the convex region in the obtained relative safe region as the ideal safe region by taking the tangent of the relative safe region boundary at the origin as the boundary; and judging the effectiveness of the resonance suppression strategy by comparing the overlap between the admittance change distribution under different resonance suppression strategies and parameters and the conservative safe region of the frequency band.

[0025] Preferably, the method further includes: based on the effectiveness analysis conclusion of the resonance suppression strategy obtained in step S5, and combined with the degree of overlap between the resonance suppression strategy and the ideal safe domain, obtaining suggestions for the selection of resonance suppression strategy and parameter optimization.

[0026] Accordingly, another aspect of the present invention also provides a computing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0027] Accordingly, another aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps of the method as described above.

[0028] Implementing the embodiments of the present invention has the following beneficial effects:

[0029] This invention provides a method, device, and storage medium for evaluating the effectiveness of resonance suppression schemes in AC distribution networks. By deriving the resonance suppression region of AC subnetwork admittance changes from a numerical perspective based on the node admittance matrix, a resonance suppression safety region is defined. This allows for efficient determination of the effectiveness of resonance suppression strategies under different resonance scenarios, avoiding matrix inversion operations. It exhibits good applicability to different types of resonance suppression strategies and is of great significance in addressing the limitations of current resonance suppression methods in terms of application scenarios and incompatibility between resonance scenarios and methods. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the main flow of an embodiment of an evaluation method for the effectiveness of AC distribution network resonance suppression schemes provided by the present invention;

[0032] Figure 2 This is a schematic diagram of the security domain distribution involved in a specific embodiment of the present invention;

[0033] Figure 3 This is a simplified AC power distribution network structure diagram involved in a specific embodiment of the present invention;

[0034] Figure 4 This is the Z(1d,1d) node impedance Bode diagram involved in a specific embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of security domain boundary verification involved in a specific embodiment of the present invention;

[0036] Figure 6 a-6d represents the distribution of existing resonance suppression methods in the d- and q-axis safe regions in a specific embodiment of the present invention;

[0037] Figure 7 a-7b are the node impedance Bode diagrams before and after the resonance suppression strategy is applied in a specific embodiment of the present invention;

[0038] Figure 8 a-8b is a schematic diagram of the original resonant frequency resonance suppression effect in a specific embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the resonant amplification phenomenon of passive damping access involved in an example of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0041] like Figure 1 The diagram shows the main flow of an embodiment of a method for evaluating the effectiveness of AC distribution network resonance suppression schemes provided by the present invention. In this embodiment, the method includes at least the following steps:

[0042] Step S1: Establish the frequency domain node admittance matrix of the distribution network, and at least obtain the node impedance amplitude-frequency distribution and the information of the active node;

[0043] Step S2: Determine the general evaluation index for the effectiveness of resonance suppression based on nodal admittance. All general evaluation indices are used to determine the effectiveness of the resonance suppression method.

[0044] Step S3 is used to determine the safe region, dangerous region, and critical boundary of resonance suppression at a single frequency.

[0045] Step S4: Based on the distribution of the node impedance resonant peaks, identify the frequency band of interest for resonance suppression, and evaluate the conservative safety domain for resonance suppression based on the frequency band of interest.

[0046] Step S5: Evaluate the ideal safe domain for resonance suppression, and evaluate the effectiveness of the admittance change of the actual suppression strategy based on the proposed safe domain boundary and conservative safe domain.

[0047] It is understood that the purpose of this invention is to propose an evaluation method for the effectiveness of AC distribution network resonance suppression schemes, in order to solve the problems of limited application scenarios and mismatch between resonance scenarios and methods in current resonance suppression methods.

[0048] Specifically, in one embodiment, in the evaluation method for the effectiveness of AC distribution network resonance suppression schemes provided by the present invention, step S1 further includes:

[0049] Step S1 further includes:

[0050] Establish the frequency domain node admittance matrix of the distribution network to obtain information such as the amplitude-frequency distribution of node impedance and the active node;

[0051] Based on the frequency domain impedance model of each device in the distribution network under small disturbances, the system node admittance matrix is ​​established.

[0052] In step S2, a general evaluation index for the effectiveness of resonance suppression based on nodal admittance is proposed, specifically including:

[0053] Taking an AC system along the d and q axes as an example, the change in admittance of the resonance suppression strategy simultaneously affects the d-axis and q-axis admittances of the nodal admittance matrix, resulting in a more complex judgment expression. Let the reshaping admittances along the d and q axes be δ... d δ q The node admittance / impedance matrix after resonance suppression is Y δdq Z δdq Taking the d-axis self-impedance of the node as an example, when resonance is suppressed, it is reflected in the node impedance as follows:

[0054] |Z δdq,f (p d ,p d )|-|Z 0,f (p d ,p d )|<0 (1)

[0055] The criterion (1) is equivalent to: |Z δdq,f (p d ,p q )| 2 -|Z 0,f (p d ,p q )| 2 <0, expanding it yields:

[0056]

[0057] Because |det(Y δdq,f )| 2 *|det(Y 0,f )| 2 >0, equation (1) is equivalent to:

[0058] |Y * δdq,f (p d ,p d )| 2 |det(Y 0,f )| 2 -|det(Y δdq,f )| 2 |Y * 0,f (p d ,p d )| 2 <0 (3)

[0059] Among them, det(Y 0,f ) is the determinant of the matrix that suppresses the admittance of the preceding node, and det(Y) δ,f () is the determinant of the matrix for suppressing post-node admittance;

[0060] It can be seen that Equation (3) is the necessary and sufficient condition for the resonance to be suppressed. That is, Equation (3) is a general evaluation index of the effectiveness of resonance suppression based on nodal admittance. When Equation (4) is satisfied, it can be judged that the resonance can be effectively suppressed.

[0061] In step S3, the safe region, dangerous region, and critical boundary for resonance suppression are determined at a single frequency, specifically including:

[0062] Define Y 0,f Remove p d p q The matrix containing the next row and column is Y. 0,f,N-2 , where N is matrix Y 0,f Dimension can be expressed as: det(Y) 0,f,N-2 ) = Y 0,N-2,r +jY 0,N-2,i δ d =δ d,r +jδ d,i δ q =δ q,r +jδ q,i ,det(Y 0,f ) = Y 0,r +jY 0,i Where j is the imaginary sign, Y * ,f(pd,pd) =y * d,r +jy * d,i Y* 0,f(pq,pq) =y* q,r +jy * q,i and Y * δdq,f (p d ,p d Expanding on this, we get:

[0063]

[0064] det(Y) δdq,f Expanding, we get:

[0065]

[0066] Substituting equations (4) and (5) into equation (3), we get:

[0067]

[0068] make:

[0069]

[0070] Substituting equation (7) into equation (6), we get:

[0071]

[0072] Since Q1>0, equation (8) is equivalent to:

[0073]

[0074] From equation (9), it can be seen that when the real part δ of the reshaped admittance is used... d,r δ d,i When the variable is used, the boundary of its resonance suppression region is a circle centered at (-Q2 / Q1, -Q3 / Q1). The circle has a radius of , and the region outside the circle is the resonance suppression region. Similar to a single variable, the boundary of the circle always passes through the origin.

[0075] Similarly, the q-axis impedance resonance suppression region when the independent variable is on the d-axis is:

[0076]

[0077] in,

[0078]

[0079] The d-axis impedance resonance suppression region when the independent variable is on the q-axis is:

[0080]

[0081] in,

[0082]

[0083] The q-axis impedance resonance suppression region when the independent variable is on the q-axis is:

[0084]

[0085] in,

[0086]

[0087] Equations (9) to (15) can be used to determine the resonance suppression region of the node impedances on the d and q axes when the independent variables are located on the d and q axes respectively.

[0088] When the real and imaginary parts of the admittance change are taken as independent variables, the boundaries of the d-axis and q-axis admittance changes of the AC subnet still appear as a circle that always passes through the origin. When the admittance change is located outside the circle, resonance is suppressed; this region is called the resonance suppression safe region. The region inside the circle is the resonance amplification region, called the resonance suppression danger region. The boundaries of the safe region / danger region are the boundaries of the resonance suppression safe region and the suppression danger region. The obtained criterion, by judging the resonance suppression / amplification effect of the admittance change at the corresponding frequency, can be used to evaluate the effectiveness of the resonance suppression method. The calculation process is simple and the effect is intuitive, avoiding the complex calculation process of solving the node impedance matrix one by one after different resonance suppression strategies are implemented.

[0089] In step S4, based on the distribution of the node impedance resonant peaks, a frequency band of interest for resonant suppression is constructed, specifically including:

[0090] The main purpose of resonance suppression is to reduce the resonance response caused by excessive impedance. Its disturbance current emission should meet the harmonic current injection standard of the public power grid node. The harmonic voltage response after resonance suppression should meet the harmonic voltage content limit. Based on this, the impedance limit of the resonance to be suppressed is determined, and the frequency band of concern for resonance suppression is further clarified. This patent uses 30% of the resonance peak impedance as the boundary to determine the frequency band of concern.

[0091] In step S4, based on the frequency band of interest, the conservative safety domain for resonance suppression is evaluated, specifically including:

[0092] Given that the frequency domain impedance of a resonance typically manifests as a resonant peak, and that the frequency bands surrounding the resonant frequency also exhibit significant impedance distributions, resonance suppression should consider not only the safe domain distribution at the resonant frequency but also the frequency bands surrounding it. Therefore, the range and frequency spacing of the resonant frequency bands of interest should be defined, and the safe domain for resonance suppression within each band should be plotted. The frequency bands of interest should be designed according to the analysis and suppression requirements under different scenarios and resonance characteristics.

[0093] In step S5, the ideal safe region for resonance suppression is evaluated, specifically including:

[0094] The application of resonance suppression strategies can affect the operating state of systems or equipment to some extent, potentially leading to reduced equipment performance and increased losses. These issues become increasingly pronounced as the change in admittance increases. Therefore, resonance suppression strategies should minimize the change in admittance while ensuring suppression effectiveness. As derived earlier, the circular boundary of the safe region always passes through the origin. That is, when the phase change at the center of the circle within the frequency band is less than 180°, a conservative safe region for resonance suppression exists around the origin, infinitely close to it. Compared to other regions with similar suppression effects, the admittance change within this region is smaller, resulting in a more ideal resonance suppression effect. Therefore, using the tangent of the conservative safe region boundary at the origin as the boundary, the convex region within the conservative safe region is defined as the ideal safe region. Any reshaped admittance with any phase within this region can effectively suppress resonance while minimizing the admittance change, thus achieving high resonance suppression efficiency.

[0095] In step S5, the effectiveness of the actual suppression strategy admittance change is evaluated based on the proposed security domain boundary and conservative security domain, specifically including:

[0096] Existing resonance suppression strategies mainly include improving control methods, adding resonance suppression equipment, and changing system parameters. The impact of implementing a resonance suppression strategy on the system's operating state can be reflected by the change in admittance in the node admittance matrix Y. For example, for a parallel capacitor C directly connected to the resonant node p... p The change in admittance ΔY before and after its connection f (p,p)=Y δ (p,p)-Y0(p,p)=sC p Let s be the independent variable of the transfer function; for a strategy to suppress resonance in a converter connected in parallel at node p, let the equivalent admittances of the converter before and after resonance suppression be y. sh0 y shδ Then △Y f (p,p)=Y δ (p,p)-Y0(p,p)=y shδ -y sh0 The effectiveness of the resonance suppression strategy can be determined by comparing the overlap between the admittance change distribution and the conservative safety domain of the frequency band under different resonance suppression strategies and parameters.

[0097] More specifically, the method of the present invention further includes: step S6, taking into account the effectiveness analysis conclusion of the resonance suppression strategy in step S5, and combining the degree of overlap between the resonance suppression strategy and the ideal safe domain, providing suggestions for the selection of resonance suppression strategy and parameter optimization.

[0098] To provide a deeper understanding of the present invention, the technical effects of the invention are illustrated below through a specific embodiment. (In conjunction with...) Figures 2 to 9 As shown.

[0099] To verify the effectiveness of the proposed resonance suppression strategy, an analytical method was developed. Figure 3 The model in the table is the object of analysis, and its parameter settings are shown in Table 1 below:

[0100] Table 1 Parameter Setting Table

[0101] <![CDATA[L1]]> 0.154H <![CDATA[P1 (distributed generator at node 4)]]> 30kW <![CDATA[C1]]> 100μF <![CDATA[P2 (load converter of node 3)]]> 20kW <![CDATA[L 2-3 ]]> 0.7mH <![CDATA[P3 (ILC between node 1)]]> 20kW <![CDATA[C3]]> 100μF <![CDATA[P4 (system injection power of node 2)]]> 18kW <![CDATA[L 1-4 ]]> 1mH <![CDATA[U ref_AC (Exchange side) 380V AC <![CDATA[C4]]> 200μF Transformer turns ratio 10kV / 380V Fundamental frequency 50Hz Leakage resistance 0.1Ω Transformer capacity 20kW

[0102] make Figure 3 The nodal admittance matrix of the mathematical model is Y, and the nodal impedance matrix is ​​Z. The modeling process is omitted here. Through analysis of the nodal impedances one by one, it is found that... Figure 3 The system shown has two resonant frequencies, 1029.9 Hz and 1126.8 Hz, and their distribution in the node impedance matrix is ​​shown in Table 2.

[0103] Table 2. Nodal Impedance Matrix and Traditional Resonance Distribution

[0104]

[0105] As shown in Table 2, the maximum amplitude of the resonance at 1029.9Hz and 1126.8Hz both occurs within the self-impedance of node 1. Therefore, the suppression effect of the resonance suppression method on both resonance points needs to be demonstrated. The Bode plot is shown below. Figure 4 As shown.

[0106] Taking the 1029.9Hz resonant point as an example, the change in self-admittance δ d The real and imaginary parts are the coordinate axes, δ d The resonance suppression amplitude of the self-impedance at 1029.9Hz under different values ​​is as follows: Figure 5 As shown in the figure, the blank area in the middle is the resonant amplification region.

[0107] Depend on Figure 5 As can be seen, the resonant amplification region is a circle with its boundary passing through the origin. The resonant suppression amplitude is uniformly distributed around the resonant amplification region and gradually increases with the distance from the center of the circle. The black curve at the boundary of the circle in the figure is the derived boundary of the resonant suppression safety region, which is consistent with the resonant suppression / amplification boundary of the node impedance, and the derivation result is correct. The derived resonant suppression safety region criterion can be used to analyze the effectiveness of existing resonant suppression methods and optimize them. Taking the virtual conductance as an example, let the d-axis and q-axis equivalent admittances of the converter before and after its addition be y, respectively. d0 y d1 and y q0 y q1 When the converter is connected in parallel at node p, the change in d-axis admittance of the virtual conductance control method is δ. d =y d1 -yd0 The change in q-axis admittance is δ q =y q1 -y q0 The self-admittance acting on node p, and the manifestation of the admittance change, are also applicable to other types of resonance suppression strategies.

[0108] Analyzing the effectiveness of resonance suppression strategies requires considering not only the suppression effect of the resonant peak impedance but also the impedance changes in the surrounding frequency bands. Some resonance suppression strategies may cause a resonant frequency shift and further amplify the resonant peak at the new resonant frequency. The obtained resonance suppression safety domain criterion can also reflect this phenomenon. Taking two resonance suppression methods—virtual conductance and passive damping with resistor-capacitor series—as examples, for the resonant points of 1029.9Hz and 1126.8Hz in this paper, taking 30% of the resonant peak impedance as an example, the resonant frequency bands are 956Hz-1069 Hz and 1100Hz-1184 Hz. Figure 6 The admittance changes were plotted for two scenarios: virtual conductance of 20S-100S, virtual capacitance of 10μF-50μF, and virtual resistance of 0.01Ω-0.05Ω. These changes were compared with the resonance suppression safe region boundary for this frequency band. The black curve in the figure represents the resonance suppression safe region boundary of the resonance peak. Figure 5 The results obtained.

[0109] Depend on Figure 6 As can be seen, with the conductance increasing from 20S to 100S, the change in admittance of the virtual conductance remains within the ideal safe region of resonance, and the distance from the danger region gradually increases with the increase of virtual conductance, meaning that the larger the virtual conductance, the better the resonance suppression effect. The change in admittance of passive damping, however, remains within the danger region of some frequency bands. This means that the addition of passive damping will lead to resonance amplification at some frequencies within the resonant frequency band, and may even lead to amplification of the resonance peak when the parameter is small. Figure 7 Taking a virtual conductance of 34S and a passive damped resistor of 0.01Ω and a capacitor of 10μF as examples, the node impedances before and after connection are plotted. It can be seen that the addition of passive damping causes a shift in the resonant frequency and results in further resonant amplification, while the addition of virtual conductance effectively reduces the impedance within the frequency band. Figure 6 The analysis results are consistent.

[0110] To verify the above phenomenon, a 1A disturbance current was injected into node 2 at 0.4s, and a virtual conductance of 34s and a passive damper with a resistance of 0.01Ω and a capacitance of 10μF were connected at 0.8s. The d-axis and q-axis harmonic voltage responses of node 1 were as follows: Figure 8 , Figure 9 As shown. Figure 8(a) and (b) are the node voltage sweep waveforms at 1029.9Hz and 1126.8Hz, respectively. It can be seen that after the virtual conductance and passive damping are connected, the d-axis and q-axis harmonic voltages are significantly reduced, which suppresses the original resonance peak. Figure 9 After passive damping is connected Figure 7 The new resonant peak value appears in the harmonic voltage sweep waveform at the frequency (1091.2Hz). After the passive damper is connected, significant harmonic amplification appears in the figure, thus verifying that... Figure 7 The analysis results are as follows.

[0111] Since passive damping and virtual conductance are both common resonance suppression methods and have been widely used in existing research, their resonance suppression effects varied significantly in the aforementioned cases. Therefore, it is necessary to evaluate the applicability of resonance suppression methods in different scenarios. This applicability analysis is crucial in... Figure 6 and Figure 7 This can be reflected in both, but Figure 7 Drawing the Bode plot of the mid-node impedance requires substituting the mathematical model of the resonance suppression method into the admittance matrix one by one and then inverting it, which involves a large amount of computation. Figure 6 The safety domain analysis focuses solely on the change in admittance. By analyzing the distribution of the change in admittance within the safety domain, the rationality of the resonance suppression method can be directly determined, and parameter tuning suggestions can be provided. The analysis results are more efficient and direct.

[0112] As can be seen from the above description, the general evaluation method provided by this invention can efficiently determine the effectiveness of resonance suppression strategies in different resonance scenarios, avoid matrix inversion operations, and has good applicability to different types of resonance suppression strategies. It is of great significance for solving the problems of limited application scenarios and incompatibility between resonance scenarios and methods in current resonance suppression methods.

[0113] In another aspect, the present invention provides a computing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements as follows: Figures 1 to 9 The steps described above. For more details, please refer to and combine with the foregoing explanation. Figures 1 to 9 The description of that will not be repeated here.

[0114] In one aspect, the present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements as follows: Figures 1 to 9 The steps described above. For more details, please refer to and combine with the foregoing explanation. Figures 1 to 9 The description of that will not be repeated here.

[0115] Implementing the embodiments of the present invention has the following beneficial effects:

[0116] This invention provides a method and apparatus for evaluating the effectiveness of resonance suppression schemes in AC distribution networks. By deriving the resonance suppression region of AC subnetwork admittance change from a numerical perspective based on the node admittance matrix, a resonance suppression safety region is defined. It can efficiently determine the effectiveness of resonance suppression strategies under different resonance scenarios, avoid matrix inversion operations, and has good applicability to different types of resonance suppression strategies. It is of great significance for solving the problems of limited application scenarios and incompatibility between resonance scenarios and methods in current resonance suppression methods.

[0117] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0118] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device for specifying modules in one or more boxes.

[0119] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the effectiveness of a resonance suppression scheme for an alternating current distribution network, characterized in that, Includes the following steps: Step S1: Establish the frequency domain node admittance matrix of the distribution network and obtain the amplitude-frequency distribution of node impedance and information of the active node; Step S2: Determine the general evaluation index for the effectiveness of resonance suppression based on nodal admittance. All general evaluation indices are used to determine the effectiveness of the resonance suppression method. Step S3: Determine the safe region, dangerous region, and critical boundary for resonance suppression at a single frequency. Step S4: Based on the distribution of the node impedance resonant peaks, identify the frequency band of interest for resonance suppression, and evaluate the conservative safety domain for resonance suppression based on the frequency band of interest. Step S5: Evaluate the ideal safe region for resonance suppression, and evaluate the effectiveness of the admittance change of the actual suppression strategy based on the proposed safe region boundary and conservative safe region. Step S2 further includes: In dq The AC system on the shaft, let d , q The shaft remodeling admittance is δ d , δ q The node admittance and impedance matrix after resonance suppression are Y δdq , Z δdq ; to the node in which it is located d axis self-impedance, determining a general evaluation index of the resonance suppression effectiveness based on the node admittance as follows: (3) When the above equation is satisfied, it is determined that the resonance energy can be effectively suppressed, where det(Y) 0,f ) is the determinant of the matrix suppressing the admittance of the preceding node; while det(Y) δdq,f () is the determinant of the matrix for suppressing post-node admittance; for d , q The remodeled admittances obtained after the change in axis admittance are respectively δ d , δ q At that time, at the frequency f The admittance matrix at the next node p of d Axis self-admittance; for d , q The changes in axis admittance are respectively 0 At that time, at the frequency f The admittance matrix at the next node p of d Axis self-admittance; Step S3 further includes: Let det( Y 0,f )= Y 0,r +j Y 0,i , Y 0,f(pq,pq) = y q,r +j y q,i The following formula is used to determine the criteria for judging the resonance suppression safety region of the admittance change: (4) As can be seen from equation (4), when the real part of the reshaped admittance is used... δ d,r virtual part δ d,i When the variable is used, the boundary of its resonance suppression region is defined by (- Q 2 / Q 1,- Q 3 / Q 1) is the center of the circle. A circle with radius is defined, and the boundary of the circle always passes through the origin. The region outside the circle is defined as the resonance suppression safe region, and the region inside the circle is defined as the resonance amplification region, i.e., the resonance suppression danger region. The boundary between the safe region and the danger region is the boundary between the resonance suppression safe region and the suppression danger region.

2. The method according to claim 1, characterized in that, In step S4, the frequency band of interest is determined with 30% of the resonant peak impedance as the boundary, and the range and frequency interval of the resonant frequency band of interest are set. The resonance suppression safety domain within each frequency band is plotted one by one.

3. The method according to claim 2, characterized in that, Step S5 further includes: Using the tangent of the relative safe region boundary at the origin as the boundary, the convex region in the obtained relative safe region is defined as the ideal safe region. The effectiveness of the resonance suppression strategy is judged by comparing the overlap between the admittance change distribution and the conservative safe region of the frequency band under different resonance suppression strategies and parameters.

4. The method according to claim 3, characterized in that, Further includes: Based on the effectiveness analysis conclusions of the resonance suppression strategy obtained in step S5, and combined with the degree of overlap between the resonance suppression strategy and the ideal safe domain, suggestions for the selection of resonance suppression strategy and parameter optimization are obtained.

5. A computing device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 4.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 4.

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